SDMS DocID 257133

FEASIBILITY STUDY

FOR

McKIN COMPANY HAZARDOUS WASTE SITE

GRAY MAINE

MARCH 1985

Prepared For

State of Maine Department of Environmental Protection Augusta Maine (Funded Through Co-operative Agreement with the US EPA)

By

Camp Dresser amp McKee Inc Boston Massachusetts

TABLE OF CONTENTS

CHAPTER PAGE

1 EXECUTIVE SUMMARY

11 Site Background 1-1 12 Nature and Extent of Problems 1-4 13 Contaminant Sources 1-14 14 Remedial Action Objectives 1-14 15 Remedial Response Criteria 1-22 16 Screening Procedure 1-23 17 Risk Assessment 1-24 18 Recommended Remedial Alternatives 1-25

2 CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

21 Cost 2-1 22 Reliability 2-2 23 ImplemeiXtability 2-2 24 Operation and Maintenance Requirements 2-2 25 Environmental Considerations 2-3 26 Safety Requirements 2-3 27 Future Land Use Restrictions 2-3

3 INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction 3-1 32 Remedial Action Alternatives 3-1 33 Closure Activities Common to All Alternatives 3-2 34 Source Control Remedial Alternatives 3-3 35 Off-Site Control Remedial Alternatives 3-22 36 Summary of Alternatives 3-35

4 ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction 4-1 42 Non-Cost Analysis 4-1 43 Cost Analysis 4-1 44 Summary of Screening 4-23 45 Risk Assessment 4-23

5 PRESENT WORTH COST ANLAYSIS

51 Cost Analysis 5-1

TABLE OF CONTENTS (Contd)

CHAPTER PAGE

6 RECOMMENDED REMEDIAL ACTIONS

61 Final Analysis of Alternatives 6-1

62 Summary of Recommendations 6-11

1

i LIST OF TABLES

TABLE PAGE

1-1 Summary of Significant Contaminated Soil Areas 1-16

1-2 Laboratory Analytical ResultsQuality Monitoring

of On-Site Soil 1-17

3-1 Laboratory Analytical ResultsMonitoring

of Groundwater Quality 3-30

3-2 Estimated Air Stripping Air Emission Concentration 3-31

3-3 Sunmary of Remedial Alternatives 3-36

4-1 Source Control shy Summary of Non-Cost Analysis 4-2

4-2 Off-Si Control shy Summary of Non-Cost Analysis 4-4

4-3 Costs Associated with Source Control Alternative 1 shy No Action with Monitoring 4-5

4-4 Cost Associated with Source Control Alternative 2Capping Hot Spots with Synthetic Membrane

shy 4-7

4-5 Costs Associated with Source Control Alternative 3A shyLimited Excavation with Off-Site Disposal at Landfill 4-8

4-6 Costs Associated with Source Control AlternativeLimited Excavation with Off-Site Incineration and Disposal

3B shy

4-9

4-7 Costs Associated with Source Control Alternative 4Limited Excavation with On-Site Incineration and Disposal

shy

4-10

4-8 Costs Associated with Source Control Alternative 5A shyLimited Excavation with On-Site Aeration and Disposal 4-11

4-9 Costs Associated with Source Control Alternative 5B shyLimited Excavation with Off-Site Aeration and Disposal 4-12

4-9A Costs Associated with Source Control AlternativeOn-Site Aeration and Capping Combination

5C shy 4-13

4-10 Costs Associated with Off-Site Control Alternative 6No Action with Monitoring

shy 4-14

LIST OF TABLES (Contd)

TABLE PAGE

4-11 Costs Associated with Off-Site Control Alternative 7A shyWithdrawal and Treatment of Groundwater at One Location 4-15

4-12 Costs Associated with Off-Site Control Alternative 7B shyWithdrawalWithdrawal

and Treatment Locations

of Groundwater Using Two 4-17

4-13 Costs Associated with Off-Site Control Alternative 7C shyWithdrawal and Treatment of Groundwater Using Three Locations 4-19

4-14 Costs Associated with Off-Site Control Alternative 8 shyRestriction on Future Development 4-21

4-15 Summary of Alternative Costs 4-22

4-16 Current Groundwater Contamination Levels at Well B-3 4-27

4-17 Cancer Risk Estimates for Chemicals Found in McKin Site Area Groundwater 4-27

4-18 Projected Drinking Water Contaminant Concentrations 4-29

4-19 Lifetime Cancer Risk Under Three Drinking Water Consumption Scenarios 4-30

4-20 Comparison of Air Monitoring Results to Exsting Regulations and Guidelines 4-34

4-21 On-Site Source Strength (Contaminant Mass) 4-37

4-22 Remedial Control Alternatives Risk Reduction Matrix 4-44

5-1 Summary of Present Worth Analysis 5-2

6-1 Location and Disposition of Buried Drums 6-9

6-2 Common Closure Actions Cost Summary 6-12

6-3 Summary of Recommended Remedial Actions Costs 6-14

1 I FIGURE

i 1-1

1-2

bull 1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

3-1

3-1A

3-2i

3-2A

3-3

3-4

3-4Ai

3-5

3-6

4-1

6-1

LIST OF FIGURES

PAGE

McKin Site Aerial Photograph 1-2

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Surficial Aquifer 1-7

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Bedrock Aquifer 1-8

Location of Off-Site Monitoring Wells 1-10

Steady State Surficial Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-12

Steady State Bedrock Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-13

Primary Areas of Shallow Soil Contamination 1-15

McKin Op-Site Soil Boring Locations (March 1984) 1-18 s

Locations of Hand Auger Borings (April 1984) 1-19

Test Pit Locations for Exploratory Excavation Program 1-20

Locations of On-Site Monitoring Wells 3-4

Bedrock Aquifer Plume with 2000 Buffer Zone 3-6

Areas of Contaminated Soils Suitable for Excavation 3-8

Proposed Hot Spot Cap Location 3-9

Cross Sections of Capping Alternatives 3-11

Inferred Surficial Aquifer Plume from Gerber (1984) 3-24

Subsurface Cross-Section A-A from Site to Royal River 3-26

Groundwater Withdrawal Well Locations Superimposed on Inferred 111-Trichloroethane Surficial Aquifer Plume 3-28

Public Water System in Vicinity of Site as of January 1984 3-33

Inferred 111-Trichloroethane Distribution in Surficial Aquifer 15 Years after Capping Site 4-31

Location of Known Buried Drums and Tank 6-10

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

TABLE OF CONTENTS

CHAPTER PAGE

1 EXECUTIVE SUMMARY

11 Site Background 1-1 12 Nature and Extent of Problems 1-4 13 Contaminant Sources 1-14 14 Remedial Action Objectives 1-14 15 Remedial Response Criteria 1-22 16 Screening Procedure 1-23 17 Risk Assessment 1-24 18 Recommended Remedial Alternatives 1-25

2 CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

21 Cost 2-1 22 Reliability 2-2 23 ImplemeiXtability 2-2 24 Operation and Maintenance Requirements 2-2 25 Environmental Considerations 2-3 26 Safety Requirements 2-3 27 Future Land Use Restrictions 2-3

3 INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction 3-1 32 Remedial Action Alternatives 3-1 33 Closure Activities Common to All Alternatives 3-2 34 Source Control Remedial Alternatives 3-3 35 Off-Site Control Remedial Alternatives 3-22 36 Summary of Alternatives 3-35

4 ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction 4-1 42 Non-Cost Analysis 4-1 43 Cost Analysis 4-1 44 Summary of Screening 4-23 45 Risk Assessment 4-23

5 PRESENT WORTH COST ANLAYSIS

51 Cost Analysis 5-1

TABLE OF CONTENTS (Contd)

CHAPTER PAGE

6 RECOMMENDED REMEDIAL ACTIONS

61 Final Analysis of Alternatives 6-1

62 Summary of Recommendations 6-11

1

i LIST OF TABLES

TABLE PAGE

1-1 Summary of Significant Contaminated Soil Areas 1-16

1-2 Laboratory Analytical ResultsQuality Monitoring

of On-Site Soil 1-17

3-1 Laboratory Analytical ResultsMonitoring

of Groundwater Quality 3-30

3-2 Estimated Air Stripping Air Emission Concentration 3-31

3-3 Sunmary of Remedial Alternatives 3-36

4-1 Source Control shy Summary of Non-Cost Analysis 4-2

4-2 Off-Si Control shy Summary of Non-Cost Analysis 4-4

4-3 Costs Associated with Source Control Alternative 1 shy No Action with Monitoring 4-5

4-4 Cost Associated with Source Control Alternative 2Capping Hot Spots with Synthetic Membrane

shy 4-7

4-5 Costs Associated with Source Control Alternative 3A shyLimited Excavation with Off-Site Disposal at Landfill 4-8

4-6 Costs Associated with Source Control AlternativeLimited Excavation with Off-Site Incineration and Disposal

3B shy

4-9

4-7 Costs Associated with Source Control Alternative 4Limited Excavation with On-Site Incineration and Disposal

shy

4-10

4-8 Costs Associated with Source Control Alternative 5A shyLimited Excavation with On-Site Aeration and Disposal 4-11

4-9 Costs Associated with Source Control Alternative 5B shyLimited Excavation with Off-Site Aeration and Disposal 4-12

4-9A Costs Associated with Source Control AlternativeOn-Site Aeration and Capping Combination

5C shy 4-13

4-10 Costs Associated with Off-Site Control Alternative 6No Action with Monitoring

shy 4-14

LIST OF TABLES (Contd)

TABLE PAGE

4-11 Costs Associated with Off-Site Control Alternative 7A shyWithdrawal and Treatment of Groundwater at One Location 4-15

4-12 Costs Associated with Off-Site Control Alternative 7B shyWithdrawalWithdrawal

and Treatment Locations

of Groundwater Using Two 4-17

4-13 Costs Associated with Off-Site Control Alternative 7C shyWithdrawal and Treatment of Groundwater Using Three Locations 4-19

4-14 Costs Associated with Off-Site Control Alternative 8 shyRestriction on Future Development 4-21

4-15 Summary of Alternative Costs 4-22

4-16 Current Groundwater Contamination Levels at Well B-3 4-27

4-17 Cancer Risk Estimates for Chemicals Found in McKin Site Area Groundwater 4-27

4-18 Projected Drinking Water Contaminant Concentrations 4-29

4-19 Lifetime Cancer Risk Under Three Drinking Water Consumption Scenarios 4-30

4-20 Comparison of Air Monitoring Results to Exsting Regulations and Guidelines 4-34

4-21 On-Site Source Strength (Contaminant Mass) 4-37

4-22 Remedial Control Alternatives Risk Reduction Matrix 4-44

5-1 Summary of Present Worth Analysis 5-2

6-1 Location and Disposition of Buried Drums 6-9

6-2 Common Closure Actions Cost Summary 6-12

6-3 Summary of Recommended Remedial Actions Costs 6-14

1 I FIGURE

i 1-1

1-2

bull 1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

3-1

3-1A

3-2i

3-2A

3-3

3-4

3-4Ai

3-5

3-6

4-1

6-1

LIST OF FIGURES

PAGE

McKin Site Aerial Photograph 1-2

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Surficial Aquifer 1-7

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Bedrock Aquifer 1-8

Location of Off-Site Monitoring Wells 1-10

Steady State Surficial Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-12

Steady State Bedrock Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-13

Primary Areas of Shallow Soil Contamination 1-15

McKin Op-Site Soil Boring Locations (March 1984) 1-18 s

Locations of Hand Auger Borings (April 1984) 1-19

Test Pit Locations for Exploratory Excavation Program 1-20

Locations of On-Site Monitoring Wells 3-4

Bedrock Aquifer Plume with 2000 Buffer Zone 3-6

Areas of Contaminated Soils Suitable for Excavation 3-8

Proposed Hot Spot Cap Location 3-9

Cross Sections of Capping Alternatives 3-11

Inferred Surficial Aquifer Plume from Gerber (1984) 3-24

Subsurface Cross-Section A-A from Site to Royal River 3-26

Groundwater Withdrawal Well Locations Superimposed on Inferred 111-Trichloroethane Surficial Aquifer Plume 3-28

Public Water System in Vicinity of Site as of January 1984 3-33

Inferred 111-Trichloroethane Distribution in Surficial Aquifer 15 Years after Capping Site 4-31

Location of Known Buried Drums and Tank 6-10

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

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o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

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34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

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-

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|

I

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I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

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i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

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t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

TABLE OF CONTENTS (Contd)

CHAPTER PAGE

6 RECOMMENDED REMEDIAL ACTIONS

61 Final Analysis of Alternatives 6-1

62 Summary of Recommendations 6-11

1

i LIST OF TABLES

TABLE PAGE

1-1 Summary of Significant Contaminated Soil Areas 1-16

1-2 Laboratory Analytical ResultsQuality Monitoring

of On-Site Soil 1-17

3-1 Laboratory Analytical ResultsMonitoring

of Groundwater Quality 3-30

3-2 Estimated Air Stripping Air Emission Concentration 3-31

3-3 Sunmary of Remedial Alternatives 3-36

4-1 Source Control shy Summary of Non-Cost Analysis 4-2

4-2 Off-Si Control shy Summary of Non-Cost Analysis 4-4

4-3 Costs Associated with Source Control Alternative 1 shy No Action with Monitoring 4-5

4-4 Cost Associated with Source Control Alternative 2Capping Hot Spots with Synthetic Membrane

shy 4-7

4-5 Costs Associated with Source Control Alternative 3A shyLimited Excavation with Off-Site Disposal at Landfill 4-8

4-6 Costs Associated with Source Control AlternativeLimited Excavation with Off-Site Incineration and Disposal

3B shy

4-9

4-7 Costs Associated with Source Control Alternative 4Limited Excavation with On-Site Incineration and Disposal

shy

4-10

4-8 Costs Associated with Source Control Alternative 5A shyLimited Excavation with On-Site Aeration and Disposal 4-11

4-9 Costs Associated with Source Control Alternative 5B shyLimited Excavation with Off-Site Aeration and Disposal 4-12

4-9A Costs Associated with Source Control AlternativeOn-Site Aeration and Capping Combination

5C shy 4-13

4-10 Costs Associated with Off-Site Control Alternative 6No Action with Monitoring

shy 4-14

LIST OF TABLES (Contd)

TABLE PAGE

4-11 Costs Associated with Off-Site Control Alternative 7A shyWithdrawal and Treatment of Groundwater at One Location 4-15

4-12 Costs Associated with Off-Site Control Alternative 7B shyWithdrawalWithdrawal

and Treatment Locations

of Groundwater Using Two 4-17

4-13 Costs Associated with Off-Site Control Alternative 7C shyWithdrawal and Treatment of Groundwater Using Three Locations 4-19

4-14 Costs Associated with Off-Site Control Alternative 8 shyRestriction on Future Development 4-21

4-15 Summary of Alternative Costs 4-22

4-16 Current Groundwater Contamination Levels at Well B-3 4-27

4-17 Cancer Risk Estimates for Chemicals Found in McKin Site Area Groundwater 4-27

4-18 Projected Drinking Water Contaminant Concentrations 4-29

4-19 Lifetime Cancer Risk Under Three Drinking Water Consumption Scenarios 4-30

4-20 Comparison of Air Monitoring Results to Exsting Regulations and Guidelines 4-34

4-21 On-Site Source Strength (Contaminant Mass) 4-37

4-22 Remedial Control Alternatives Risk Reduction Matrix 4-44

5-1 Summary of Present Worth Analysis 5-2

6-1 Location and Disposition of Buried Drums 6-9

6-2 Common Closure Actions Cost Summary 6-12

6-3 Summary of Recommended Remedial Actions Costs 6-14

1 I FIGURE

i 1-1

1-2

bull 1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

3-1

3-1A

3-2i

3-2A

3-3

3-4

3-4Ai

3-5

3-6

4-1

6-1

LIST OF FIGURES

PAGE

McKin Site Aerial Photograph 1-2

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Surficial Aquifer 1-7

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Bedrock Aquifer 1-8

Location of Off-Site Monitoring Wells 1-10

Steady State Surficial Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-12

Steady State Bedrock Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-13

Primary Areas of Shallow Soil Contamination 1-15

McKin Op-Site Soil Boring Locations (March 1984) 1-18 s

Locations of Hand Auger Borings (April 1984) 1-19

Test Pit Locations for Exploratory Excavation Program 1-20

Locations of On-Site Monitoring Wells 3-4

Bedrock Aquifer Plume with 2000 Buffer Zone 3-6

Areas of Contaminated Soils Suitable for Excavation 3-8

Proposed Hot Spot Cap Location 3-9

Cross Sections of Capping Alternatives 3-11

Inferred Surficial Aquifer Plume from Gerber (1984) 3-24

Subsurface Cross-Section A-A from Site to Royal River 3-26

Groundwater Withdrawal Well Locations Superimposed on Inferred 111-Trichloroethane Surficial Aquifer Plume 3-28

Public Water System in Vicinity of Site as of January 1984 3-33

Inferred 111-Trichloroethane Distribution in Surficial Aquifer 15 Years after Capping Site 4-31

Location of Known Buried Drums and Tank 6-10

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

1

i LIST OF TABLES

TABLE PAGE

1-1 Summary of Significant Contaminated Soil Areas 1-16

1-2 Laboratory Analytical ResultsQuality Monitoring

of On-Site Soil 1-17

3-1 Laboratory Analytical ResultsMonitoring

of Groundwater Quality 3-30

3-2 Estimated Air Stripping Air Emission Concentration 3-31

3-3 Sunmary of Remedial Alternatives 3-36

4-1 Source Control shy Summary of Non-Cost Analysis 4-2

4-2 Off-Si Control shy Summary of Non-Cost Analysis 4-4

4-3 Costs Associated with Source Control Alternative 1 shy No Action with Monitoring 4-5

4-4 Cost Associated with Source Control Alternative 2Capping Hot Spots with Synthetic Membrane

shy 4-7

4-5 Costs Associated with Source Control Alternative 3A shyLimited Excavation with Off-Site Disposal at Landfill 4-8

4-6 Costs Associated with Source Control AlternativeLimited Excavation with Off-Site Incineration and Disposal

3B shy

4-9

4-7 Costs Associated with Source Control Alternative 4Limited Excavation with On-Site Incineration and Disposal

shy

4-10

4-8 Costs Associated with Source Control Alternative 5A shyLimited Excavation with On-Site Aeration and Disposal 4-11

4-9 Costs Associated with Source Control Alternative 5B shyLimited Excavation with Off-Site Aeration and Disposal 4-12

4-9A Costs Associated with Source Control AlternativeOn-Site Aeration and Capping Combination

5C shy 4-13

4-10 Costs Associated with Off-Site Control Alternative 6No Action with Monitoring

shy 4-14

LIST OF TABLES (Contd)

TABLE PAGE

4-11 Costs Associated with Off-Site Control Alternative 7A shyWithdrawal and Treatment of Groundwater at One Location 4-15

4-12 Costs Associated with Off-Site Control Alternative 7B shyWithdrawalWithdrawal

and Treatment Locations

of Groundwater Using Two 4-17

4-13 Costs Associated with Off-Site Control Alternative 7C shyWithdrawal and Treatment of Groundwater Using Three Locations 4-19

4-14 Costs Associated with Off-Site Control Alternative 8 shyRestriction on Future Development 4-21

4-15 Summary of Alternative Costs 4-22

4-16 Current Groundwater Contamination Levels at Well B-3 4-27

4-17 Cancer Risk Estimates for Chemicals Found in McKin Site Area Groundwater 4-27

4-18 Projected Drinking Water Contaminant Concentrations 4-29

4-19 Lifetime Cancer Risk Under Three Drinking Water Consumption Scenarios 4-30

4-20 Comparison of Air Monitoring Results to Exsting Regulations and Guidelines 4-34

4-21 On-Site Source Strength (Contaminant Mass) 4-37

4-22 Remedial Control Alternatives Risk Reduction Matrix 4-44

5-1 Summary of Present Worth Analysis 5-2

6-1 Location and Disposition of Buried Drums 6-9

6-2 Common Closure Actions Cost Summary 6-12

6-3 Summary of Recommended Remedial Actions Costs 6-14

1 I FIGURE

i 1-1

1-2

bull 1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

3-1

3-1A

3-2i

3-2A

3-3

3-4

3-4Ai

3-5

3-6

4-1

6-1

LIST OF FIGURES

PAGE

McKin Site Aerial Photograph 1-2

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Surficial Aquifer 1-7

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Bedrock Aquifer 1-8

Location of Off-Site Monitoring Wells 1-10

Steady State Surficial Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-12

Steady State Bedrock Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-13

Primary Areas of Shallow Soil Contamination 1-15

McKin Op-Site Soil Boring Locations (March 1984) 1-18 s

Locations of Hand Auger Borings (April 1984) 1-19

Test Pit Locations for Exploratory Excavation Program 1-20

Locations of On-Site Monitoring Wells 3-4

Bedrock Aquifer Plume with 2000 Buffer Zone 3-6

Areas of Contaminated Soils Suitable for Excavation 3-8

Proposed Hot Spot Cap Location 3-9

Cross Sections of Capping Alternatives 3-11

Inferred Surficial Aquifer Plume from Gerber (1984) 3-24

Subsurface Cross-Section A-A from Site to Royal River 3-26

Groundwater Withdrawal Well Locations Superimposed on Inferred 111-Trichloroethane Surficial Aquifer Plume 3-28

Public Water System in Vicinity of Site as of January 1984 3-33

Inferred 111-Trichloroethane Distribution in Surficial Aquifer 15 Years after Capping Site 4-31

Location of Known Buried Drums and Tank 6-10

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

LIST OF TABLES (Contd)

TABLE PAGE

4-11 Costs Associated with Off-Site Control Alternative 7A shyWithdrawal and Treatment of Groundwater at One Location 4-15

4-12 Costs Associated with Off-Site Control Alternative 7B shyWithdrawalWithdrawal

and Treatment Locations

of Groundwater Using Two 4-17

4-13 Costs Associated with Off-Site Control Alternative 7C shyWithdrawal and Treatment of Groundwater Using Three Locations 4-19

4-14 Costs Associated with Off-Site Control Alternative 8 shyRestriction on Future Development 4-21

4-15 Summary of Alternative Costs 4-22

4-16 Current Groundwater Contamination Levels at Well B-3 4-27

4-17 Cancer Risk Estimates for Chemicals Found in McKin Site Area Groundwater 4-27

4-18 Projected Drinking Water Contaminant Concentrations 4-29

4-19 Lifetime Cancer Risk Under Three Drinking Water Consumption Scenarios 4-30

4-20 Comparison of Air Monitoring Results to Exsting Regulations and Guidelines 4-34

4-21 On-Site Source Strength (Contaminant Mass) 4-37

4-22 Remedial Control Alternatives Risk Reduction Matrix 4-44

5-1 Summary of Present Worth Analysis 5-2

6-1 Location and Disposition of Buried Drums 6-9

6-2 Common Closure Actions Cost Summary 6-12

6-3 Summary of Recommended Remedial Actions Costs 6-14

1 I FIGURE

i 1-1

1-2

bull 1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

3-1

3-1A

3-2i

3-2A

3-3

3-4

3-4Ai

3-5

3-6

4-1

6-1

LIST OF FIGURES

PAGE

McKin Site Aerial Photograph 1-2

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Surficial Aquifer 1-7

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Bedrock Aquifer 1-8

Location of Off-Site Monitoring Wells 1-10

Steady State Surficial Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-12

Steady State Bedrock Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-13

Primary Areas of Shallow Soil Contamination 1-15

McKin Op-Site Soil Boring Locations (March 1984) 1-18 s

Locations of Hand Auger Borings (April 1984) 1-19

Test Pit Locations for Exploratory Excavation Program 1-20

Locations of On-Site Monitoring Wells 3-4

Bedrock Aquifer Plume with 2000 Buffer Zone 3-6

Areas of Contaminated Soils Suitable for Excavation 3-8

Proposed Hot Spot Cap Location 3-9

Cross Sections of Capping Alternatives 3-11

Inferred Surficial Aquifer Plume from Gerber (1984) 3-24

Subsurface Cross-Section A-A from Site to Royal River 3-26

Groundwater Withdrawal Well Locations Superimposed on Inferred 111-Trichloroethane Surficial Aquifer Plume 3-28

Public Water System in Vicinity of Site as of January 1984 3-33

Inferred 111-Trichloroethane Distribution in Surficial Aquifer 15 Years after Capping Site 4-31

Location of Known Buried Drums and Tank 6-10

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

1 I FIGURE

i 1-1

1-2

bull 1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

3-1

3-1A

3-2i

3-2A

3-3

3-4

3-4Ai

3-5

3-6

4-1

6-1

LIST OF FIGURES

PAGE

McKin Site Aerial Photograph 1-2

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Surficial Aquifer 1-7

111 Trichloroethane Plume as Plotted by Gerber (1982) in the Bedrock Aquifer 1-8

Location of Off-Site Monitoring Wells 1-10

Steady State Surficial Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-12

Steady State Bedrock Aquifer (1984) 111 Trichloroethane Contaminant Plume 1-13

Primary Areas of Shallow Soil Contamination 1-15

McKin Op-Site Soil Boring Locations (March 1984) 1-18 s

Locations of Hand Auger Borings (April 1984) 1-19

Test Pit Locations for Exploratory Excavation Program 1-20

Locations of On-Site Monitoring Wells 3-4

Bedrock Aquifer Plume with 2000 Buffer Zone 3-6

Areas of Contaminated Soils Suitable for Excavation 3-8

Proposed Hot Spot Cap Location 3-9

Cross Sections of Capping Alternatives 3-11

Inferred Surficial Aquifer Plume from Gerber (1984) 3-24

Subsurface Cross-Section A-A from Site to Royal River 3-26

Groundwater Withdrawal Well Locations Superimposed on Inferred 111-Trichloroethane Surficial Aquifer Plume 3-28

Public Water System in Vicinity of Site as of January 1984 3-33

Inferred 111-Trichloroethane Distribution in Surficial Aquifer 15 Years after Capping Site 4-31

Location of Known Buried Drums and Tank 6-10

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

CHAPTER 1

EXECUTIVE SUMMARY

11 Site Background

The McKin facility was constructed in 1972 in an abandoned sand and gravel pit and presently consists of a fenced enclosure containing an incinerator a concrete block building and an asphalt lined lagoon The entire site is

approximately 7 acres with approximately 45 acres being cleared (see EPA Aerial Photograph - Figure 1-1) Prior to 1972 the sand and gravel pit was

allegedly used to store contaminated by-products from tank cleaning

The facility is located in a rural residential area with an estimated population of 300within a half mile radius of the site The closest

residence is 300 feet northeast of the site

The operation was originally constructed to accommodate waste generated from an oil spill The owner also accepted tank bottoms of 6 and 4 oil

septic tank wastes and industrial process wastes Approximately 100000 to 200000 gallons were received annually by the McKin facility between

1972 and 1977 while the facility was operated as a transfer station

As early as 1973 nearby residents of East Gray reported odors in well water and discoloration of laundry In response to these complaints Mr

Robert McNally Town of Gray Code Enforcement Officer collected samples from the affected private off-site wells and submitted them for laboratory

analysis Subsequent analyses showed the presence of 111-trichloroshyethane dimethyl sulfide trichloroethylene (TCE) acetone trimethylsishy

lanol xylene freon and alcohols in a private well (Sullivan property) five on-site tanks and in the site soils As a result of these findings an Emergency Health Ordinance was Issued by the Town of Gray placing a

moratorium on any new construction within about two miles of the site

1-1

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

Il IM

t__l in Jraquo

ltn f gt (raquo 410 8raquoijraquo

^ Vpoundlaquofe)fshy3S

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

In November 1977 Fred C Hart Associates a contractor to the US EPA

conducted a hydrogeologic assessment of the area Their results showed

that contamination had reached many of the local private wells On 12

December 1977 a Cleanup Order was Issued to the McKin Company In mid-

December 1977 16 contaminated private water supply wells were capped

bullemergency water supplies were brought in by truck to service the residents

and in 1978 the public water supply was extended to the affected area

During the summer of 1979 the Maine Department of Environmental Protection

(DEP) supervised the removal of liquid waste from the site however some

tank sludge not removable by pumping was left on-site Twelve monitoring

wells were installed by DEP in 1979 to assess groundwater contamination

During the spring and summer of 1980 DEP collected soil and groundwater

samples at the site and in the course of their investigation detected

possible buried drums of unknown contents and other cells of buried material and contaminated soil Concentrations in excess of 17000 ppb of

111-trichloroethane were reported

In 1982 DEP contracted Robert G Gerber Inc to conduct hydrogeologic

studies in the Gray area and to study the groundwater contamination problem

in East Gray including the development of a computer model of the

groundwater regime under and near the site The report estimated the exshy

tent of the contamination plume the time required for aquifer self-cleansshying and possfble means of accelerating aquifer cleansing

In April 1983 DEP contracted with Jetline Pollution Control of South

Portland Maine to perform the following tasks

- Rinse and crush approximately 150 drums and 40 other containers

- Collect and dispose of rinse solution

- Repair the site fence

- Clean and remove a 3000 gallon tank

- Examine the remaining tanks

In August 1983 Jetline conducted Initial Remedial Measure (IRM) work at the site including

1-3

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

2-2

25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

2-3

CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

3-1

o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

3-2

i

gt

]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

3-3

NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

3-10

bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

3-13

345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19

- 21 above ground tanks were cleaned gas-freed and removed from the site

- Approximately 10500 gallons of liquid (including rainwater rinse water and contaminated water from the tanks) were removed from the site and taken to Union Chemical South Hope Maine or Recycling

Industries in Braintree Massachusetts for disposal

- 18 yards (11 tons) of solid material along with the drums of solidishyfied sludge and solid material left during previous cleanup work

were shipped to SCA Chemical Service Model City New York

- A chainlink fence with a locking gate was installed across the front of the facility to prevent vehicular access

- The original chainlink fence surrounding the inner facility was

repaired

- Warnings signs were posted around the outside perimeter of the facishylity and along the inside fence warning that tb e facility contained

materials determined to be hazardous by DEP and EPA

In January 1984 Camp Dresser amp McKee Inc (COM) entered into a contract with DEP to conduct a Remedial Investigation and Feasibility Study (RIFS) for the site under a Cooperative Agreement signed with EPA Region I in June

1983

12 Nature and Extent of Problems

The field work for the Remedial Investigation (RI) for the McKin site

completed in August 1984 indicates that the site has been partially secured which should preclude additional dumping or waste disposal on-site

However areas of residual contamination remain in the on-site soils Natural infiltration of precipitation is causing these contaminants to

migrate down through the unsaturated zone into the groundwater The extent and degree of the groundwater contamination is described below

1-4

I 121 Groundwater Contamination

Robert G Gerber Inc has modelled the surficial and bedrock aquifer conshy

taminant plumes emanating from the McKin site Two models were used to

accurately characterize the contaminant plumes The first model

AQUIFEM-1 was used to depict groundwater movement away from the site The

second model the Konikow and Bredehoeft solute transport model was used

to simulate contaminant transport in the aquifers

AQUIFEM-1 (AQUIfer Hnite Element poundodel - 1-layer) was developed at

the Ralph M Parsons Laboratory for Water Resources and Hydrodynamics

located at the Massachusetts Institute of Technology The code is oriented

toward the most common situation encountered by the geohydrologist a

two-dimensional roughly horizontal aquifer of large area extent This

type of aquifer is Described by a mathematical equation called the tj

aquifer or hydraulic equation which is simulated numerically in AQUIFEM-1 using the Galerkin finite element technique Anisotropic heterogeneous phreatic or confined leaky or non-leaky aquifers under transient or steady state conditions can be modeled A change of aquifer status from phreatic to confined or vice-versa is also allowed Time varying boundary conditions may be used where specified heads or specified point lateral or areal recharge or discharge rates are given With the proper combinations of these boundary conditions the code can model pumping wells recharge wells constant drawdown flowing wells springs drains excavation dewatering groundwater discharge to surface depresshysions evapotranspiration the effects of geologic faults and the exchange of water between the aquifer and fully or partially penetrating surface water bodies AQUIFEM-1 can also be used to examine certain 2 dimensional vertical cross-sectional views of an aquifer

The Konikow and Bredehoeft model simulates solute transport in flowing groundwater The model is both general and flexible in that It can be applied to a wide range of problem types It is applicable to one- or two-dimensional problems involving changes in concentration over time caused by the processes of convective transport hydrodynamic dispersion and mixing (or dilution) from fluid sources The model assumes that the

1-5

solute is non-reactive and that gradients of fluid density viscosity and temperature do not affect the velocity distribution However the aquifer may be heterogeneous and (or) anisotropic

The model couples the groundwater flow equation with the solute-transport equation The digital computer program uses an alternating-direction

implicit procedure to solve a finite-difference approximation to the groundshywater flow equation and it uses the method of characteristics to solve the

solute-transport equation The latter uses a particle-tracking procedure to represent convective transport and a two-step explicit procedure to solve a

finite-difference equation that describes the effects of hydrodynamic dispersion fluid sources and sinks and divergence of velocity This

explicit procedure has several stability criteria but the consequent time-step limitations are automatically determined by the program

The November 1982 study determined that groundwater passing under the site in the surficial aquifer flows to the northwest initially until encountershying a coarse gravel deposit travelling east-west under the intersection of

Pownal and Maya1 Roads (see Figure 1-2) After entering the gravel deposit the contaminant plume flows eastward and surfaces in the vicinity

of Boiling Springs before being discharged to the Roy^l River The study stated that all groundwater which flowed under the McKin site ultimately

discharged to the Royal River

The 1982 study also suggested that the bedrock contaminant plume leaves the

site in a northerly direction but then spreads out diffusely due to the fractured bedrock (see Figure 1-3) The study suggests that the greater extent of the bedrock contamination is associated with the pumping of

residential bedrock wells in the area causing elevated levels of contashyminants to enter the bedrock aquifer These wells are no longer used but the initial contamination has occurred

It should be noted that there has never been any documentation to suggest that any contaminants exist east of the Royal River Isocons which project

beyond the river are the result of computer interpolation of the data and the physical layout of the river

1-6

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC 111 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER N

On Center Plaza (1982) IN THE SURFICIAL AQUIFER Boalon Massachusetts 02106 FIGURE 1-2

McKIN SITE QUAY MAINE CAMP DRESSER McKEC MC N 1 1 1 TRICHLOROETHANE PLUME AS PLOTTED BY GERBER On Claquonllaquor Plata

Boalon Massachusetts 02 1 06 (1982) IN THE BEDROCK AQUIFER FIGURE 1-3

The computer model applied in 1982 was calibrated using groundwater quality data collected in the area during that study The model predicted that contaminants entering the site groundwater would reach Boiling Springs after about five (5) years with the contaminant plume reaching a steady state condition or estimated peak concentrations in ten (10) years A

steady state plume is defined as a plume which remains unchanged in terms

of spatial extent and concentrations The steady state model assumes a continuing source of contaminants throughout the modelling period

111-trichloroethane was selected as a target contaminant for groundwater

modeling based upon the availability of historical data Data obtained at

Boiling Springs from July 1979 to March 1981 showed 111-trichloroethane concentrations ranging from 03 to 370 parts per billion (ppb) Gerber used an average contaminant level of 200 ppb at Boiling Springs and from this simulated the contaminant plume isocons as shown in Figure 1-2

During the Remedial Investigation (RI) ten monitoring wells were installed

at five locations B-l through B-5 (see Figure 1-4) and the water samples

obtained allowed the surficial and bedrock flow and contaminant transport

models developed previously by Gerber to be revised and recalibrated as part of this study The 1984 boring program determined that there were

three (3) major differences in conditions between the predictions of previous models and results based upon field borings These three

inconsistencies include

1) Under Mayall Road just west of Pownal Road 1984 boring B-5 found thick stratified fine sands where it was previously interpreted

to consist primarily of glacial till overlain by a small thickness of sand and gravel The observed water table in B-5 was much lower than previously predicted

2) The highly permeable surficial deposits thought to exist 1n the area of 1984 boring B-4 were not found however the relatively

low water table position observed in B-4 suggests that a highly permeable deposit does exist to the north of B-4

1-9

LEGEND

B-101 ^ through V deg

LLLgt B-104 J

^hrough

NUMBER OF WELL WELLS AT

LOCATION LOCATION

B-l 2

B-2 3

B-3 2

B-4 1

B-5 2 SCALE fneoo

McKIN SITE GRAY MAINE CAMP DMC8S0I McKCC MC N On Claquonllaquor Pllaquou

LOCATIONS OF OFF-SITE MONITORING WELLS Botlon MawachuMtU 02108 (BASE MAP FROM U3OS QRAY QUADRANGLE) FIG 1-4

3) Previous reports assumed that the areas of glaciomarine clay deshyposits were saturated from the phreatic surface in the clay

through to the bedrock aquifers The 1984 boring program did not confirm this The clay deposits have an entirely separate perched water table as found in boring B-4

Based on information obtained from the 1984 boring program Gerber recalishybrated his model and the path of groundwater travel was revised such that

the computer simulations show the groundwater is leaving the site in a north-northeasterly direction The groundwater is depicted as then

circling toward Boiling Springs and the Royal River (See Fig 1-5)

Information on groundwater flow piezometric heads and soil conditions obtained during the 1984 program has caused Gerber to speculate based on computer modeling that there is much more water flowing under the site than previously estimated Instead of a 21 (uncontaminated aquifer flow to site produced contaminated groundwater flow) dilution rate at the site as previously thought the revised model predicts a 101 dilution rate

The revised model also predicts a lower off-site dilution path than previously calculated The results from the computer modeling indicate

that following complete source or contaminant removal the aquifer will cleanse itself naturally to 111-trichloroethane contaminant levels less

than 10 ppb in 25 years

Figure 1-5 shows the surficial aquifer contaminant plume once it reaches a steady state condition The model predicts that the steady state condition

will be established approximately 13 years after the contaminants were Introduced to the groundwater As the contaminants were gradually added

from 1972 to 1977 it is assumed that the steady state (peak contaminant concentrations) condition will be attained during the 1985-1990 time

period

The projected steady state bedrock aquifer contaminant plume 1s shown in Figure 1-6 It is estimated that it will take a total of 15 years for the

bedrock aquifer to reach steady state conditions as compared to the 13 years for the surficial aquifer

1-11

McKIN SITE GRAY MAINE CAMP DME88CRA McKS INC N On Center Plaza STEADY STATE SURFICIAL AQUIFER (1984) Boclon MlaquoraquoMchuM(tlaquo 02 1 08

111-TRICHLOROETHANE CONTAMINANT PLUME FIGURE 1-5

0- SOD- vxxy 7

laquo00~ l9OCQflf tfamp

McKIN SITE GRAY MAINE CAMP DRESSER A MIcKOEINC NSTEADY STATE BEDROCK AQUIFER (1984) On Center Plaza

111-TRICHLOROETHANE CONTAMINANT PLUME Boston Massachusetts 02 1 06 FIGURE 1-6

The levels of observed on-site soil contamination are sufficient to act as a source of continuing groundwater contamination for several years if remedial actions are not initiated Isolation or removal of the contamishynants would reduce the groundwater contamination sources within the unsatushyrated zone The groundwater plume could be mitigated by either extraction and treatment or the natural processes of volatil ization biodegradation

absorption and neutralization

13 Contaminant Sources

During the RI six areas within the site which were contaminated due to oil solvents and other materials were identified It is estimated that these areas (see Figure 1-7) total approximately 19100 square feet Soil groundwater surface water and sediment samples were analysed for volati le

organics heavy metals extractable organics and PCB compounds Analyses of the groundwater have identified the presence of only two (2) contamishy

nants in the groundwater 111-trichloroethane and trichloroethylene An on-site soils investigation program including augering and test pit

excavation has determined that only a portion of the 19100 sq ft area is acting as a contaminant source which requires remedtal action (Tables

1-1 and 1-2 and Figures 1-8 through 1-10) The hand augering program consisted of using an HNu photoionizer in conjunction with a grid network to systematically define areas where an HNu volatile organic reading of greater than 5 ppm was encountered Auger borings were taken 5 feet apart until the edge of the contaminated area was located as signified by a less than 5 ppm HNu reading and then 25 feet intervals were used The vertical

limits of contamination were determined by monitoring every auger cutting with an HNu Once again soil which registered greater than 5 ppm on the

HNu was classified as contaminated Those areas determined to emit volatiles in excess of 5 ppm during the field screening process were

defined as contaminant sources requiring remedial action The same procedure was used during the test pit program in order to further define contaminated areas It should be noted that the field screening was validated with analytical analyses for volatile organics extractable

organics heavy metals and PCB compounds If analytical results did not validate the field screening the area was not considered a contaminant

1-14

NOTTS

AREA 16

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER A McKEE INC

PRIMARY AREAS OF SHALLOW SOIL CONTAMINATION Onlaquo Claquonllaquor Plata Boston Massachusetts 021 OB

FIGURE 1-7

TABLE 1-1

SUMMARY OF SIGNIFICANT CONTAMINATED SOIL AREAS

Estimated Dimensions

Description of Surface Area Contamination Area (sf) Depth(ft) Volume (cy)

Area IB Grey and black sludge 400 5 74 (see TP13A amp TP138 Lab Tests)

TPI 1A Soil Around Buried Drum (Area 6 ) (See Figure 6-1) 9 3 1

Area 3 See TP6A Lab Tests 1500 40 2222

Area 4 See SS01amp SS02 Lab Tests 3200 3 356

TP 15 See TP15 Lab Tests 100 2 8 (Area 5)

TOTAL 5209 2661

ESTIMATE 5200 sf ESTIMATE 2700 cy

NOTES

1 Areas 1A 1C and 2 were not determined to be significantly contaminated based on laboratory analysis and physical observations The major conshytaminants in these areas appear to be typical derivatives of petroleum refining and not covered under CERCLA

2 The estimated depth for Area IB is estimated as debris would not allow auger penetration The remaining depths are estimated based on physical visual field observations

Due to limitations of sampling device exact depth of contamination cannot be determined therefore the depth to groundwater was used as a conservashytive figure

See Table 1-2 for lab test results

1-16

1 TABLE 1-2

LABORATORY ANALYTICAL RESULTS OF ON-SITE SOIL QUALITY MONITORING (mgkg) bull (See Figures 1-81-9 and 1-10 For Locations)

- UJ z UJ ^ gtshy

z o o M

ETH

YLE

NE

C

HLO

RID

E

IRIC

HLO

RO

ETH

YLE

NE

111-

TR1C

HLO

RO

ETH

AN

E

UJ

Z Ul

UJ

_J Ul CD

_J

Z UJ mdash UJ X

YLE

NE

S

OIC

HLO

RO

BE

NZE

NE

TOLU

EN

E

AR

SE

NIC

sect

i CA

DM

IUM

CH

RO

MIU

M

gUJ

MER

CU

RY i

ec Z UJ jJ J UJ

uO

Smcle Location

Sample Numoer

Deptn (Feet)

SS01 SjJl SSJ1 SSU1 SSUl SSU2 SS03 5S03 SSOb 5S03 5S05J

SS05U2 SSJiD

1 2 3 4 b 1 1 i 1 Z 3 a 5

u-1 3

11-12 fgt-7

11-1Z 0-2 0-1 0-1 0-2 O-Z

10-11 14-15 14-15

ND ND ND ND

70 ND ND ND ND

NP NU

ND ND

-shyNO ND L

f -bull ND ND

ND

ND Nl

1500 ND TJD 240

17 52 29

NH ND ND ND

21 NDND ND ND ND ND

ND ND ND ND

50 ND ND 16 99 27 12

ND ND ND ND

24 ND TO 250 200 gt33 05

NO ND ND NT

21 NO ND 580 b70

gt67 HI

ND

ND ND

9 ND ND 30 87 13 17

90

15

ltZ5 ltZ5 75

75

ZO

10

lt01 25

3 ~gt

ltZ^)

SSib 5 SO SSU7 SSJS ssoe SiO^ SSOB SSDS S509

1 1 1 2 3 4 b 1

0-1 4-3 2-3 3-4 3-4 3-4

3 3 b

ND ND ND ND ND ND

ND

ND ND ND NO 005 fO

ND

ND ND ND ND ND NO

ND

ND NP ND ND ND ND

ND

ND ND ND ND ND ND

ND

ND ND ND NT 003 to

ND

ND ND ND ND ND ND

ND

10 I

lt25 lt5

lt25 ltZ5

75 95

22 ta

lt01 lt0 1

lt5 lt75

lt70 lt 0

SSIH SSI1 55G-) seoi Sbui

2 3 4

1 2

3-4 3-4

3 5-6

10-11

ND ND

ND ND

ND ND

ND ND

ND ND

NO ND

ND 004

ND 30Z

NJ 622

ND ND

NT ND

ND DIT

3tl ltZ5 ltZ5 3ff lt1 1) ltn i ltZ 5 ltzo

SB02 SB03 SD01

sooz

5 1

25-26 5-6

NO ND

ND ND

NO ND ND ND

NO ND

001 ND

ND ND

ND ND ND ND

ND 002 ND ND

NO 12 ND ND

TP4A TP4B TP6A TP9B IPl J TP13B TP15

1R 44 4B SA 9B

13A 136 15laquo

ltl ltl ltbull 49 lt lt lt

560 laquol lt 1

1400 ltl lt 1 ltl

03raquo lt1 ltl 45 ltl U4W

69

zznlaquo O ltl 10

lt i U4W

03 gt10

ISO ltl ltbull

a ltl i 05raquo gt^0 gt10

09 ltl ltl 06 ltl ltl 10 gt30

bull Approxlnately bullbull SMple Uken July 10 1984 bullntlyzed September 4 1984

flue to delay specific concentrations are unknown bull raquo tytene not analyzed for in this sanple NO bull Below Detection Liaits ft bull Held lUnk

Volatiles were analyzed on a wet weight basis Metals were analyzed on a dry weight basis

1-17

I I IL I I I I I NOUS

SCALE

KEY

BORING LOCATIONS

McKIN SITE QRAY MAINE NTRUE MC

McKIN ON-SITE SOIL BORING LOCATIONS (MARCH 1984)

On Center Ptaia bullMlon MMMChUMfe Oil Ot

FIGURE 1-8

NOTTS

nn nv utltlt air

bulllaquolaquo

I t-laquo VO

SCALE

McKIN SITE QRAY MAINE NTRUE CAMP DHttSBI McKEE IMC

On Claquonllaquor Ptau LOCATIONS OF HAND AUGER BORINGS (APRIL 1984) bullolon MlaquoMlaquochualaquo(traquo 02106

FIGURE 1-9

MOTES

MIH Plaquo bulllaquobull I

SCALE

MeKIM SITE GRAY MAINE TRWE CAMP OHC8SCR ft McKEE INC

TEST PIT LOCATIONS FOR EXPLORATORY On Claquontlaquor Plau

EXCAVATION PROGRAM FIGURE 1-10

source Other than the contaminated soils the only remaining known source of potential contamination is a buried 3000 gallon tank with approximately

350 gallons of fuel oil remaining in it

14 Remedial Action Objectives

The existing data and information on the nature and extent of on-site and off-site contamination at McKin was used to establish remedial response

objectives The objectives are

(1) To maintain adequate safe drinking water supply for the population that could be affected by groundwater contaminant migration

(2) To prevent direct local exposure via inhalation or dermal contact to contaminated material (soil sediments leachate)

(3) To protect State-designated Royal River surface water users from contaminant release

The Royal River is currently classified B-2 by the State of Maine which

means swimmable-fishable This classification 1s the desired quality of the river and corresponds to a target of 60 percent of the saturation dissolved oxygen limit but not less than 5 ppm Fecal col i forms should not exceed 200 in 100 ml and pH should be between 60 and 85

Regarding these objectives it should be noted that all private water supply wells that have been impacted by the plume to date have been replaced by a permanent public water supply system although one affected

resident has chosen not to connect to the public system The water supply

system has adequate capacity and pipelines such that it can be extended to cover any new residential development in the Town of Gray

High levels of contamination have been identified in on-s1te soils The

installed fencing has restricted access to the site thereby limiting any

Immediate hazards The surface water sediment analyses completed during the RI have not shown the presence of contamination and there was no

1-21

evidence of contaminated leachate impacting any potential receptors in any

of the surface water analyses completed during the RI

The Royal River and Col Iyer Brook have been sampled on several occasions

and no significant levels of contamination have been observed Some conshy

taminants were found in the Royal River in trace quantities in the past

but analyses completed April 1984 could not detect any contaminants at

either location

15 Remedial Response Criteria

The EPA has published both health advisories and Recommended Maximum

Contaminant Levels (RMCLs) for trichloroethylene and 111-trichloroeshy

thane which were the only contaminants found in the contaminant plume A

long-term health advisory is defined as a suggested no adverse response

level (SNARL) for a 10 kg infant drinking 1 liter per day of contaminated

water over a 70 year period The long-term health advisory for trichloshy

roethylene is 75 ppb and 1000 ppb for 111-trichloroethane The RMCLs

for trichloroethylene and 111-trichloroethane are 0 ppb and 200 ppb

respectively The State of Maine Bureau of Health (BOH-) has published

drinking water guidelines which are somewhat stricter than the EPA health

advisories for these two chemicals The Maine Maximum Exposure Guidelines

(MEGs) are 45 ppb for trichloroethylene and 330 ppb for 111-trichloroeshy

thane Also the EPA Ambient Water Quality Criteria for Freshwater Aquatic

Toxicity (18000 ppb for 111-trichloroethane and 45000 ppb for TCE) were

examined relative to potential impacts upon fish in the Royal River or

Collyer Brook These criteria were supplemented by the following criteria

which have been applied as an evaluation tool for comparison of remedial

action alternatives at other hazardous waste sites

(1) Any treatment of the contaminated groundwater plume will be conshy

tinued until the maximum concentration of combined TCE and 111shy

trichloroethane in the groundwater plume as determined at the exshy

traction well pump is 50 ppb This criterion which has been

used by EPA at other cleanup sites was used to reduce the levels

of contamination in the aquifer to below the Maine MEGs even

1-22

though there is no current use of the aquifer for drinking water

supplies

(2) Recharge to groundwater in a clean aquifer (one that meets drinkshy

ing water standards) is to be at or below 50 ppb combined TCE and 111-trichloroethane During remedial action and prior to achieving cleanup of the aquifer recharge for cleansing purposes can be at concentrations higher than 50 ppb provided such recharge is part of an overall treatment system plan and restricted geographically to an area that will ultimately be cleaned up to within the 50 ppb criterion

(3) Effluent from any groundwater treatment facility discharged to the

Royal River or Col Iyer Brook is not to exceed 50 ppb combined TCE

and 111-trichloroethane concentrations

16 Screening Procedure

The remedial alternatives evaluated during this study were screened at two separate points The initial screening eliminated those alternatives from further consideration which were technically infeasible or created no significant benefit over alternatives incurring less cost Alternatives evaluated but eliminated during the initial screening phase included

1 No action

2 Capping entire cleared area of the site 3 Using clay as the capping material 4 Installing a containment wall around the contaminated areas 5 On-site soil encapsulation 6 Discharging treated groundwater to the Royal River 7 Recovering contaminated groundwater from fractured bedrock

The remaining alternatives were then evaluated based on environmental and

technical concerns reliability Implementability operations and mainteshy

nance (0AM) requirements health and safety considerations and cost The

1-23

alternatives evaluated during the second screening were either on-site

source control or off-site control and included the following

1 On-Site Source Control

o Alt 1 - No Action with monitoring

o Alt 2 - Capping of contaminated soil areas with synthetic

membrane

o Alt 3A - Excavation of contaminated soil with off-site landfill

disposal

o Alt 3B - Excavation of contaminated soil with off-site

incineration

o Alt 4 - On-site incineration of contaminated soil with on-site

landfilling

o Alt 5A - On-site aeration (landfarming) and landfilling of

contaminated soil

o Alt 5B - Off-site areation (landfarming) and landfilling of

contaminated soil

o AJt 5C - On-site aeration and capping of contaminated soil

combination s

2 Off-Site Control f

o Alt 6 - No Action with monitoring

o At 7A 7B 7C - Withdrawal wells with groundwater treatment and on-site recharge

o Alt 8 - Restriction on future development

17 Risk Assessment

Three pathways of exposure to hazardous substances were evaluated during

the study ingestion of contaminated groundwater inhalation of volatile

organics and dermal contact with on-site contaminated soil The populashy

tions at risk evaluated were humans including adjacent residents on-site

workers and unauthorized persons gaining access to the site and aquatic

species in the Royal River

1-24

-4 A review of the findings indicates that there is a 362 x 10 lifetime

cancer risk associated with drinking the groundwater at its current levels of contamination Natural cleansing of the aquifer will reduce the risk level to approximately 483 x 10 in 25 years

Jhe risk assessment results indicate that the population at greatest risk due to inhalation of contaminated air is the on-site workers during the implementation of the remedial actions These workers should use respiratory protective equipment during on-site work Analysis has also determined that any excavation or on-site aeration of the contaminated soil will result in downgradient TCE concentrations which are 150 of the ambient levels represented as guidelines by the New York State Department of Environmental Conservation (NYSDEC) and EPA Multimedia Environmental

Goals and as currently under review by the Maine Bureau of Health Therefore off-site emissions of volatile organics is not considered a

problem at the Mckj site

The risks to aquatic species in the Royal River and to persons coming in dermal contact with contaminated soils were both evaluated and eliminated as insignificant in the risk assessment completed during this study

18 Recommended Remedial Alternatives

As a result of the final screening process two remedial action options or combinations of on-site and off-site controls are recommended for impleshy

mentation These include (1) Alternative 2 (capping the contaminated

areas) in combination with Alternative 7C (Withdrawal and treatment of goundwater at three locations) and (2) Alternative 5A (on-site aeration)

with Alternative 7C

Alternative 1 the No Action source control alternative was determined to be non-responsive to the groundwater contamination issue and was eliminated

as unacceptable from a health and safety perspective Alternative 3A the off-site landfilling of the contaminated soil was not recommended due to

the high transportation and disposal costs necessary to dispose of the soil at an approved facility as compared to the benefits realized The off-site

1-25

incineration alternative Alternative 4 was eliminated from consideration

due to the impractical handling and shipping constraints placed on the conshytaminated soil by the incineration facility Alternative 5B which

consists of the off-site aeration of the contaminated soil was not

recommended over the on-site aeration or capping alternatives due to the

unavailability of off-site locations Alternative 5C which would involve aerating five of the contaminated areas on-site and capping one area has the lowest capital cost associated with it but due to the contamination remaining under the cap a monitoring program would be required The monitoring costs create an alternative life-time or present worth cost greater than that of alternative 5A which upon implementation would

achieve the same remedial results Therefore Alternative 5C is not recommended over Alternative 5A

Implementing either Alternatives 2 or 5A would with relatively low total costs isolate or eliminate the groundwater contaminant source Alternashytive 5A would require excavating and aerating the soil on-site thus creating increased voTatilizatfon of organics which will create significant odors Alternative 5A would also require the DEP and EPA to establish treatment levels necessary for the aerated soil to be reclassified as

non-hazardous This would also necessitate that trea^tablity studies be completed during the design phase to verify that the treatment levels can

be attained Although the risk assessment results have determined that volatilization of organics poses a risk to on-site workers only (who will be protected during on-site work) Alternative 2 would achieve the same remedial end without disturbing the contaminated soil thereby reducing the health risks associated with volatilization of contaminated soil Therefore Alternative 2 is favored over Alternative 5A

Alternative 6 (No Action with Monitoring) was eliminated from consideration as being non-implementable due to institutional constraints It is estishymated that the implementation of Alternative 7A 7B or 7C which consist of

groundwater withdrawal at various points and on-site treatment and recharge would reduce the clean-up period from 10 years (Alternative 6) to approximately 5 years Although Alternative 7C would require significant expenditures of funds and would also require wells to be constructed on

1-26

private property the EPA has determined that Alternative 7C is the only off-site alternative evaluated which is in compliance with RCRA guidelines relative to contaminants leaving the site Therefore Alternative 7C is the recommended off-site remedial alternative

Alternative 8 the placing of restrictions on future development in the bullarea should be implemented as a non-structural option in combination with

Alternative 7C

1-27

CHAPTER 2

CRITERIA FOR EVALUATION OF REMEDIAL ACTION ALTERNATIVES

Alternatives identified as having the potential to meet the remedial resshyponse objectives for the McKin site were subjected to a two-step evaluation process The first step consisted of an initial screening of the candidate alternatives (see Chapters 3 and 4) based on relative present worth cost environmental impacts and engineering considerations Following the initial screening the narrowed list of remedial alternatives was evaluated further in order to identify the most cost-effective alternative This second evaluation step rates the alternatives according to six criteria cost reliability implementability operation and maintenance requirements

environmental impacts and safety requirements tj

f

21 Cost

Evaluation of alternatives by cost utilized the present worth (life-cycle) method with a 30-year planning period and a 10 percent discount rate

Useful life projections for major components of the alternatives were designated as follows structures (except containment walls)mdash50 years treatment units wells and containment wallsmdash25 years and mechanical equipmentmdash15 years These projections are for costing purposes only

Capital costs were estimated for the individual components of the altershynatives The estimated construction costs were based on September 1984 dollars and an Engineering News Record (ENR) cost index of 4175 An allowance for engineering and contingencies was included in the total capital cost as noted in the detailed cost estimates in Chapter 4

Annual operation and maintenance costs for the individual components include labor power chemicals maintenance and supplies Labor cost was based on the estimated number of hours required for the operation of the

facilities and includes allowances for fringe benefits sick leave and health insurance Power cost includes power for pumping operating equipshy

2-1

ment and other purposes Cost for maintenance and supplies includes routine equipment replacement parts and other miscellaneous items needed

for the daily operation of the facility Separate cost estimates for equipment and buildings were obtained for the treatment facilities Annual maintenance costs were assumed to be 10 percent of the capital cost

Major components were assumed to have no salvage value (100 percent depreshyciation) at the end of their useful lives

22 Reliability

A comparison and ranking of the alternatives was performed based on the

ability of the particular alternative to achieve long-term control of contaminant release and the potential for and consequences of failure of

any component of the remedial plan Factors influencing an alternatives reliability rating include time to achieve control level of control to be expected system complexity and degree of proven technology to be employed

23 Implementability

j s

For each alternative substantial constraints to rapnl implementation such as difficult permit requirements or complex construction phasing were

identified Also examined was whether options are available to segment the plans implementation Factors influencing the implementability ranking include off-site facility and pilot study requirements institutional

issues and public acceptability

24 Operation and Maintenance Requirements

The alternatives were compared in terms of system flexibility maintain- ability and operability Factors examined included staffing levels and special operator training requirements from both an operations standpoint

and a handling and disposal of hazardous materials standpoint plant and well monitoring frequency and levels and laboratory needs increased system

maintenance demands (due to the nature of the materials involved) and energy requirements

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25 Environmental Considerations

Each alternative was evaluated for potential impacts on the physical

biological and socioeconomic environment Within these three categories

the major environmental indicators of concern were surface water and

groundwater quality aquatic and terrestrial life and public health

26 Safety Requirements

Remedial action alternatives were evaluated with respect to 1) the require ment for plant personnel to handle hazardous substances or contaminated materials 2) the production of explosive gases that could endanger on-site workers or nearby residents 3) the potential for generation of toxic

airborne gases 4) off-site transportation of hazardous materials and 5) fire hazards

27 Future Land Use Restrictions

Although future land use is not an EPA sanctioned criteria for evaluating alternatives the remedial actions considered in the study were evaluated to the restriction their implementation would place on the site Some

alternatives may reduce restrictions on future use of the site by removing or decontaminating the contaminated soils By placing covers or caps over

the site other alternatives may restrict future excavation on-site which would be associate with building foundations baseball backstop supports o

underground utilities

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CHAPTER 3

INITIAL SCREENING OF REMEDIAL ACTION ALTERNATIVES

31 Introduction

The purpose of the initial alternative screening process is to identify the

most viable and feasible alternatives for remedial action at the McKin site In order to eliminate those alternatives which are either inapproshy

priate or not feasible screening criteria were established as follows

a Technical Feasibility b Environmental Impact

c Institutional Considerations

d Cost

Each of the alternatives was evaluated based on the above criteria

32 Remedial Action Alternatives

The remedial action alternatives considered in this analysis address the

two areas identified as potentially needing remedial action in the RI groundwater contamination and on-site soil contamination A list of

remedial action alternatives was compiled for on-site (source) remedial actions which will mitigate the contaminated soil impacts as well as

off-site remedial action technologies which will address the groundwater

issue The list of remedial actions evaluated during this study is not all Inclusive but 1s a 11st of alternatives which are commonly used to remediate problems similar to those found at McKin The alternatives evaluated Include

Source Control

o No action o No action with monitoring

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o Capping the site

o Installing a containment wall and capping

o Excavation and off-site disposal

o Excavation with on-site incineration and disposal

o Excavation with on-site renovation and disposal

o Excavation with off-site renovation and disposal

Off-Site Control

o No action

o No action with monitoring

o Pumping treating and reinjection of groundwater to contaminated

aquifer or discharge to Royal River

o Provision for public water supply

o Restriction on future development

33 Closure Activi t ies Common to All Alternatives

There are certain aspects associated with the McKin site cleanup and

closure which are common to all proposed remedial alternatives including

the No Action alternative and will not be addressee during the initial

screening of alternatives These include

o Disposal of all above ground on-site debris (ie hoses rags etc)

o Disposal of on-site metallic structures (ie incinerator conveyor

system piping tubing etc)

o Demolition and disposal of masonry block building o Filling of the existing asphalt lagoon

o Removal and disposal of known buried steel and fiber drums o Removal and disposal of buried 3000 gallon tank located south of-

masonry building

o Fencing of site

These closure activities will be discussed in greater detail as part of the

recommended remedial action

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i

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]

34 Source Control Remedial Action Alternatives

341 No Action

The No Action alternative is self-explanatory The adoption of this alternative would signify that the site as it exists today does not have any adverse impacts on the environment sufficient to warrant any action now or at any time in the future This type of determination requires that the site is accurately and exactly characterized and that there are no unknown or unanswered questions pertaining to the site its potential contaminants or future risks Due to the inherent assumptions used in the computer

modeling and interpreting the field data at McKin it is felt that the No Action alternative is not adequately responsive to warrant further consideration

J

342 No Action frith Monitoring

The No Action With Monitoring alternative would also allow the site to

remain in its present condition indefinitely Current physical processes now occurring on-site such as groundwater contamination would continue

unimpeded for at least 25 years The contaminated soils would continue to act as sources of groundwater contamination during the 25 year time period Groundwater monitoring will be established to determine if the contaminashytion leaving the site was increasing or decreasing Since the process of rainfall infiltration and migration is naturally cleansing the contaminated on-site soils presently at the expense of the local groundwater quality this alternative would use natural forces to remedy the soil contamination

This results in movement of the contaminants to the groundwater and in time (over 25 years) the contaminants would also be flushed naturally from the groundwater system

Monitoring would consist of sampling four on-site monitoring wells W-101

W-102 W-103 W-104 as shown on Figure 3-1 The analytical procedure would be to test the wells for contaminants annually for 30 years Also each

well would be tested quarterly for volatile organics for the first three years The volatile organic sampling frequency would decrease to semishy

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NDKS

00 I

gt

LEGEND

EXISTING WELL

PROPOSED WELL

LD WELL LOCATION (WELL REMOVED)

SCALE

McKIN SITE GRAY MAINE

LOCATIONS OF ON-SITE MONITORING WELLS

NTRUE CAMP DRESSER A MCKEC me On Claquonllaquor Plata Boston MaasachuMlU 02106

FIGURE 3-1

annually during the fourth and fifth years assuming earlier analyses showed a marked contaminant reduction It is estimated that a significant

i clean-up trend would be established after the five year period to eliminate j the need for volatile organic sampling after the first 5 years The

quantitative definition of significant trend would be determined by the results of the initial years of analyses The monitoring would allow DEP to determine the rate at which the natural precipitation flushing process

was decontaminating the on-site soil

The No Action With Monitoring alternative has potentially the most severe

environmental impact of all the remaining alternatives considered Under this alternative the existing groundwater contamination will continue

j However the public health impact of this contamination has been mitigated to a large extent as a public water supply has been made available to all affected adjacent hdtneowners

s

From an institutional point of view the implementation of this alternative would require continued availability of public water to any new development in the area above the contaminated aquifers indefinitely In order to be conservative on the side of safety 1t is recommended that a restriction on

installing drinking water wells be extended beyond the estimated limits of j the contaminant plume to the area shown in Figure 3-1A The cost

associated with the No Action With Monitoring alternative would consist of the post-closure groundwater monitoring program including sampling laboratory analyses and data evaluation

343 Capping the Site

f 1 There are two different capping alternatives as well as two different capping materials which could be utilized at the McKin site The first of

the two alternatives would cap the entire cleared area of the site or approximately 45 acres Due to the topography of the site 1n particular

the existing low areas of the site extensive regrading is required prior to the capping of the entire site Approximately 60000 cubic yards of

] fill would have to be brought to the site at a cost of approximately $600000 Otherwise the capping of the low spots would create ponding or

3-5

EXTENT OF INFERRED bullEDROCK PLUME

McKIN SITE

tOOO SUFFER ZONE AROMNO IHFlimiD CONTAMINATED bullEDROCK PLUME

AMcKKMC MoKIN SITE GRAY MAINE N INFERRED BEDROCK AQUIFER PLUME FROM GERBER (1984) On Center Ptou WITH 2000 BUFFER (RESTRICTION) ZONE BoMon fttasMChuMMs 02106

FIGURE 3-1A

1

j

-

i

|

I

|1

I

1

I

wet areas which are not desirable Based on the regrading required along with the observation that most of the site soils are not contaminated the

capping of the entire site was eliminated from further consideration

The second capping alternative consists of capping only those areas which field and laboratory test results show as being contaminated These areas of contaminated soil are shown on Figure 3-2 and total approximately 580 square yards The limits of the contaminated areas were defined based on an extensive hand augering program wherein auger holes were placed five feet on centers around a center area originally determined to be contamishy

nated by laboratory analysis of soil boring samples The auger holes were made out from the center until an HNu reading less than 5 ppm was found

This procedure defined the lateral extent of the contaminated areas Laboratory analyses were used to validate the field observations (see Table

1-2)shy

RCRA guidelines require that each closure cap have 4 monitoring wells (3 down-gradient and 1 up-gradient) dedicated solely to each cap Therefore it is impractical to incur the well installation and annual analytical costs required for capping each hot spot separately It is proposed to

Incorporate four hot spots (Areas IB 3 4 5) under one cap Due to the impractical ity of including Area 6 under the same cap it is proposed that

Area 6 be excavated and landfilled off-site as part of this alternative The closure cap for the four areas totals approximately 5600 square yards

(sy) (see Figure 3-2A) once allowances are taken into account for subsurface horizontal dispersion of the contaminants The estimated cost

to cap 5600 sy of area and install 4 wells is approximately $46000 The cost to cap each individual hot spot and install 15 wells 1s approximately

$63000 Therefore the 1 cap alternative is less expensive even without taking the potential Increased analytical costs associated with multiple

caps into account The benefits gained by each capping alternative are essentially equal

As capping the entire 45 acre open area is impractical from an engineering

point of view and capping tiraquo individual hot spots separately would incur greater capital and monitoring costs 1t is proposed that the capping

3-7 I

NOUS

CO

AREA

SCALE

McKIN SITE GRAY MAINE NTRUE CAMP DRESSER McKEE INC

AREAS OF CONTAMINATED SOILS On Center Plau Boston MMlaquochuM(U 02106 RECOMMENDED FOR EXCAVATION

FIGURE 3-2

Ul I

AREA 6

AREA 6

PROPOSED HOT SPOT CAP

SCALE

MoKIN SITE QRAY MAINE NTRUE CAMP DRESSER ft McKEE INC

On Claquonllaquor Plaza PROPOSED HOT SPOT CAP LOCATION BtMlon MaSMchuMM 021 OS FIGURE 3-2A

alternative to be considered further involves covering all of the hot

spots except Area 6 with one cap Area 6 would be excavated and disposed

of off-site

The alternative capping materials include an impervious clay and a synthetic membrane The two alternative impermeable layer cross sections

are shown in Figure 3-3

The clay cap consists of a 2 foot thick clay layer installed over the existing contaminated soil to act as a barrier to any infiltration of

rainfall into the contaminated soil The one foot thick sand layer which is placed over the clay acts as a drain for the vegetation supporting loam

layer It has been assumed that this one foot sand layer will be obtained from uncontaminated on-site sandy soils The synthetic membrane cap cross section is the same except a synthetic membrane is used as an impervious barrier to infiltration instead of the 2 foot clay layer The installation

of a synthetic membrane will require regrading of the on-site sandy soil to

insure that no rocks or debris will puncture the membrane

f The capping alternative chosen will have to meet the Resource Conservation

and Recovery Act (RCRA) requirements for site closure (40 CFR Part 264) The current RCRA policy states that any liner or cap placed over a site has

to be less permeable than the liner under the site In the case of McKin there is no liner under the site and both clay and synthetic membranes are

less permeable than the existing sandy soil The RCRA policy also requires a layer of soil on top of the cap which can support vegetation The one

foot loam layer meets this requirement for both alternatives All other conditions of RCRA compliance are met by either proposed capping altershy

native The synthetic membrane has the advantages of being approximately 30 cheaper than the clay and being less permeable The synthetic membrane

will create more limitations for future use of the site as any future excavation will compromise the integrity of the membrane by establishing

stress points which may tear or rip in the future Once a hole is put in the membrane for a building foundation it is difficult to produce an

effective seal around the foundation A clay cap has the advantage of

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bullmdash

iiniiHiiiiiiJIHiiiiinHiiniinii jffiifttntittiiiiiiintfnittiimi 111 tttn tttj j j j

Clay Cap

Surface Grade

1 Ft Loom Layer

1 FltSondLlaquo|laquor (from on-slte source)

2 Ft day Layer

Existing Contaminated So (aroded)

Surface Grode

vvXvXvXvX X X X 1 FtloomLoyer

1 Ft Sond Loyer bull bull bullbull -v bull v bullbull bullbullbullbull bullbull - (from on-site source)

40 ml Synthetic Membrone

1 Ft Sond Loyer (from on-fit sowoe)

ittttititinnttiiiiiinf SinHnSinHiifiinHii

Existing ContwiiHMJed Solaquo (graded)

j|mmjjrjifi|fmmjftjjmmnutttmiitimit

liiiiiiniiiiiiiiiniliiiniiiiiiniiliiiiiiiiiiiiiiiii

Synthetic Membrane Cap

McKIN SITE GRAY MAINE CAM DRESSER ft McKEE INC

CROSS SECTIONS OF CAPPING ALTERNATIVES On Center Plaza Boston Massachusetts 02108

FIGURE 3-3

being easier to reseal It should be noted that future use is not an issue which EPA considers relevant to alternative selection

It is mentioned here only to evaluate the entire impact the alternative would have on the environment

A review of the McKin site shows that those areas proposed to be capped are relatively flat or can be regraded easily Also the limitations that the use of the membrane will impose on future development of the site appear to be modest considering the sites potential future uses Therefore the use

of a clay layer will not receive any future consideration and the capping alternative being considered will consist of placing a synthetic membrane over the contaminated soils

The installation of the impermeable cap does not require accompanying soil excavation except for the 1 cubic yard of material which would be excavated in Area 6 The cap functions by minimizing infiltration and percolation of precipitation through the contaminated soils in the unsaturated zone The

net result is that future production of contaminated groundwater associated with contaminants in the unsaturated zoneis minimized

f

344 Installing a Containment Wall and Capping the Site

The instaTation of a containment wall in conjunction with capping the conshytaminated soil areas would be completed to prevent contaminated groundwater from migrating away from the site divert uncontaminated groundwater away from the contaminated soils at the water table and isolate the source materials in the unsaturated zone At the McKin site the groundwater is

approximately 30 feet below the contaminated soil and the proposed cap would prevent infiltrated water from coming into contact with the soil

contaminants Therefore the role of the containment wall is to prevent the further spread of groundwater contamination To accomplish this the

containment wall must extend either to an impervious subsurface layer below the groundwater table which in this case is bedrock or to a shallower

depth (hanging wall) with internal groundwater pumping to prevent additional vertical migration of contaminants

3-12

The bedrock in the vicinity of the McKin site has been found to be fracshytured such that installing a containment wall down to bedrock would not totally eliminate groundwater transport as fractures in the bedrock would continue to allow groundwater movement away from the site In order to

completely contain the groundwater pumping within the wall would still be required over at least the next 10 years to induce the vertical flow

gradients necessary to contain contaminants within the confines of the wall

It is estimated that a hanging containment wall must extend down a minimum

of 60 feet to intersect the groundwater table Due to the relatively small surficial size of the contaminated areas it is impractical to contain each area separately It is estimated that a 900 foot perimeter wall would encircle the entire contaminated area at the McKin site With an estimated construction cost jjr $7square foot the estimated cost to install the required containment wall is approximately $378000 This cost is signifishycantly higher than the estimated cost of $51460 to cap the contaminated soil It should be noted that the hanging wall would contain only the contaminated groundwater immediately underlying the contaminated site soils which are contained within the wall Capping would be required along with

the wall to minimize the infiltration of precipitation

The capping of the area above the contaminated soil will effectively remove the contaminated soil as a potential source of groundwater contamination The availability of a public water supply also mitigates the Impact of the groundwater contamination The need to or benefit gained by installing

containment walls around the areas of contaminated soil does not appear to warrant further consideration in light of the fact that the only advantage it presents over capping is containment of a very small portion of the contaminated groundwater plume In addition the lack of a well defined

and structurally sound bedrock layer would require internal pumping and long term treatment of pumped water Finally 1t is Important to recognize

that because of the depths of wall required it is less costly to excavate the shallow contaminated soil rather then contain the soil Therefore

containment walls are eliminated from further consideration

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345 Excavation and Off-Site Disposal

The second group of source control alternatives evaluated all involve excavation of the contaminated soil These alternatives consist of identishy

fying the areas of contamination excavating those areas and hauling the soil off-site by truck Due to the concentrations of trichloroethylene and

other chlorinated solvents in the soil the contaminated material must be transported out of state if it is to be disposed of without treatment as there are no permitted disposal sites in state which can accept soil with chlorinated solvent concentrations (TCE and 111-trichloroethane) greater than 500 ppm

Two off-site disposal processes were evaluated during this initial screening phase These were landfill ing and incineration The incineration alternashy

tive would consist of transporting the soil to the Rollins Environmental Services Inc incinerator in Bridgeport New Jersey with final post-incineration disposal in a municipal landfill The Rollins incinerator the only known incineration facility which will accept contaminated soil is designed to incinerate drums and not bulk material such as soil Therefore there are some severe restrictions regarding the packaging and handling of

the soil prior to incineration Rollins requires that all soil be burned in 40 gallon fiber drums and that the maximum filled weight of each drum be less

than 200 pounds Using an estimated density of 100 pounds per cubic foot for the contaminated on-site material results in the maximum volume of soil

or sand which can be shipped per 40 gallon drum being 15 gallons or 20 cubic feet A tractor trailer truck can carry approximately 40000 pounds in

weight or 3384 cubic feet in volume Each truck can therefore carry approximately 375 fiber drums by volume but only 200 drums by weight This

inefficiency leads to increased transport costs

The landfilling option consists of landfilling the contaminated soil at a secure hazardous waste landfill Due to the high chlorinated solvent (TCE)

Loose mixed grain sand unsaturated Foundation Engineering Ralph B Peck et al (1974)

3-14

concentrations the soil cannot be landfilled within the State There are several sites east of the Mississippi River the closest of which are located in Buffalo and Model City New York These sites have been periodically closed by the EPA for permit violations and therefore it cannot be guaranteed that they will be open when the McKin remedial work is initiated The next closest site is located in Emelle Alabama approximately 1700 miles from

Gray In order to obtain a conservative cost estimate it is assumed that the contaminated on-site soil will be trucked to Emelle Alabama for disposal

The excavation of the contaminated soil has both distinct advantages and hazards associated with it During excavation the on-site personnel and excavating equipment will be in contact with the contaminated soil Therefore procedures must be followed during excavation so as to protect the on-site personnel from exposure to the contaminants Also the equipment will haveto be decontaminated prior to leaving the site Excavation of thesoil will also serve to aerate the soil thereby

permitting the volatile organics to discharge to the atmosphere The possible extent or severity of the resulting air contamination is evaluated

during the final alternative screening phase

Excavation of contaminated soils will remove the source of contamination from the site This has an advantage over capping the site in that there would be no restrictions on the future use of the site and there would be no membrane or clay cap below the surface which could be affected by future excavation

The off-site disposal would also require several permits to be obtained by DEP The transportation of the contaminated soil by truck would require

that Department of Transportation regulations be met along with those of the states through which the truck will pass The disposal by landfill would require a chemical analysis of representative loads of soil to validate that the material can be accepted by permit at the receiving

hazardous waste disposal site The same chemical analysis would also have to be performed prior to incineration to insure compliance with the operating specifications for the permitted facility

3-15

The landfilling of the soil in a secure hazardous waste landfill essentshyially transfers the environmental impacts from an uncontrolled site to a secure and controlled disposal area Therefore the adverse impacts associated with the soil are minimized but not eliminated altogether

The use of an incinerator followed by landfilling for ultimate disposal

assumes that the incineration will allow the hazardous waste (contaminated soil) to be reclassified as non-hazardous and therefore acceptable to local

municipal landfills as cover material If the soil cannot be reclassified then incineration becomes an extraneous and costly step in the treatment

process The soil would still have to be landfilled as a hazardous material so incineration would not achieve any added benefit over landshyfilling without incineration Should reclassification become unattainable then the use of an incinerator for final disposal is not economically

acceptable and will not receive any further consideration Incineration has the effect of rendering the soil non-hazardous The burning of the soil would destroy the volatile organics At this time the Rollins incinerator is permitted to accept contaminated soil such as those soils

at the McKin site for incineration With the air scrubbers in place as required by permit the adverse environmental impacts^gtf incinerating the

soil would be mitigated

346 Excavation and On-Site Disposal

This alternative also involves excavation of the contaminated sand but instead of transporting it off-site the sand would be treated and disposed

of on-site Several on-site treatmentdisposal options were evaluated These included landfilling encapsulation on-site aeration or landfarming and incineration Landfilling the contaminated soil achieves no improvement over the existing situation unless the soil is either decontaminated prior to landfilling or it is encapsulated Due to its dependence on treatment options the on-site landfilling option will be reviewed in connection with

other treatment options discussed in subsequent sections On-site encapsulation requires that the soil be excavated and stockpiled A

synthetic liner would then be placed covering the bottom and sides of the excavation Once the soil is backfilled a clay or synthetic cap would be

3-16

placed on top of the contaminted soil totally Isolating the contaminated soil from the adjacent clean soil A review of the results achieved by

encapsulation shows that essentially the same reduction 1n contaminant transport can be gained by just capping the contaminated areas as discussed previously Therefore it is not cost-effective to expend the added cost to totally encapsulate the contaminated soil and therefore encapsulation will

not receive any further consideration

On-site incineration is similar to the off-site option discussed in the previous section The on-site incinerator has the advantage of eliminating

both the transport of the contaminated soil to an off-site location and the requirement of putting the soil in 40 gallon fiber drums The disadvantage shyassociated with this alternative when compared to the off-site disposal is that the temporary portable incinerator will have to have sufficient air

cleaning capacity yo comply with DEP air quality standards s

There are two types of portable incinerators currently available One would be a trailer mounted rotary kiln incinerator built by a private company The company would install the incinerator on-site operate it for the duration and then dismantle the incinerator for shipment off-site Companies that have stated that they have the resources to Incinerate the required amount of contaminated soil are Therm-All Inc in Peapack New Jersey Can-A-Van Technologies also in New Jersey and MAS Corporation in Connecticut These units are rotary kiln incinerators with a capacity range of 1500 to 3000 poundshour

Should the State and EPA decide to Initiate remedial action without responsible party assistance then a second portable incinerator option is available The EPA Research and Development Section in Edison New Jersey has a portable incinerator which consists of four trailers containing a rotary kiln Incinerator a combustion chamber a pollution control system and a monitoring system The EPA would Install the incinerator operate it and remove it for an estimated cost of $8000day (January 1985 quote from EPA-Edison) The incinerator would operate 24 hoursday and has a capacity of approximately 3000 pounds of soilhour

3-17

Although the EPA incinerator is significantly less expensive to operate (see Table 4-7 in Section 4) than the private units there are two associated concerns If the remedial clean-up is to be completed by the responsible parties then the EPA incinerator cannot be used Also the EPA incinerators schedule is established based on site priority It is uncertain at this time if McKins priority would allow the incinerator to

be dedicated to the site at the appropriate time

Once again this alternative will receive futher consideration only if the incinerated soil can be placed or landfilled back on-site as a contaminant

free soil RCRA regulations state that once the contaminated soil is reshymoved or excavated the repositioning of the soil on-site requires that the site be designated a secure hazardous waste landfill unless the treated soil can be reclassified as clean Therefore prior to landfilling the

excavated material back on-site it is proposed to incinerate the soil and designate the residue as being non-hazardous At this time discussions

with EPA-RCRA staff have established that the reclassifying of the soil will be based on mutually agreed upon action limits as established by the

EPA and the DEP Once the soils contaminant concentration is decreased to f

below the action limits by whatever treatment processthen the soil can be t

landfilled back on-site without violating RCRA regulations Therefore it would appear at this time that the on-site incineration alternative is

worthy of further consideration

347 Excavation and On-Site Renovation

The on-site aeration or landfarming alternative consists of decontaminating the soil in-place using relatively simple mechanical equipment The

procedure would be to skim off as much of the uncontaminated soil as possible It is proposed that an HNu reading less than 5 ppm or equal to

background levels whichever is lower would allow the soil to be classishyfied as clean The clean soil would be skimmed off or pushed out of the contaminated area The remaining contaminated soil surface would be rototilled with a tractor mounted rototiller in one foot lifts The

surface would be tilled once every 2 days until head space jar test monitoring showed a contaminant concentration less than the agreed upon

3-18

level in the tilled layer The decontaminated (aerated) soil (1 foot deep)

would be scraped off the surfaceand deposited out of the contaminated area The procedure would be continued until monitoring determined that the remaining soil contamination was below the action limit Once all of the soil had been treated the area would be backfilled to grade

Along with the aeration process it is also proposed that natural biological oxidation of the volatile organics be encouraged This landfarming procedure would consist of tilling in fertilizer during the aeration

process This would increase the organic content of the normally inorganic on-site sand to a point whereby natural bacteria would break the

contaminants down to non-hazardous compounds Due to the strength of the carbon-chlorine bonds in TCE and 111-trichloroethane the effectiveness of bacterial decomposition will be decreased but any degree of effectiveness will off-set the low fertilizer costs Therefore the aerationlandfilling alternative will involve aeration nutrient supplementation and mixing

s

Soil aeration was implemented at the Martys GMC site in Kingston

Massachusetts Analyses of the aerated soil showed a signficant reduction

(approximately 80) in volatile organics in the soil after 4 days of aeration Based on results realized at a Kingston New Hampshire site it

is estimated that two til lings will be required to reduce the volatile contaminants to acceptable levels although a treatability test would be

required during design to verify this estimate The other contaminants in the soil are heavy metals in low concentrations (2-15 ppm) as shown in Table 1-2 In order for this alternative to be in compliance with RCRA guidelines the soil must be decontaminated relative to both volatiles and heavy metals Although no action limits have been established by the EPA and the DEP to date it Is assumed that the heavy metals in the soil which would be unaffected by the aeration process must pass the EP Toxicity Test as regulated in RCRA Section 26124 Treatability tests would have to be

completed during the design phase to insure that the heavy metal concentrashytions were below EP Toxicity maximum concentrations However based on a comparison of other contaminated soils similar to those at McKin and their corresponding EP Toxicity concentrations it is felt that the resultant heavy metal concentrations at McKin would be below EP Toxicity levels and

3-19

that aerating the soil both on- and off-site would be in full compliance with RCRA guidelines It is recormended that treatability studies be

completed during the design phase in order to verify that adequate treatment levels can be attained

The primary adverse impact associated with this alternative is that during the on-site aeration the volatile organics are released to the atmosphere producing significant odors while also posing a potential public health

hazard to people in the vicinity of the site A continuous on-site and off-site monitoring program is required during the aeration program to

assess potential health effects The monitoring would utilize a portable gas chromatograph to provide real time monitoring of one indicator

compound such as TCE Should monitoring show concentrations greater than background levels at the nearest residence than aeration will be

temporarily stopped

The advantages of the on-site aeration are the low cost and the lack of sophisticated mechanical equipment required to implement

Due to sampling equipment limitations there is one arapof the site Area 3

(see Figure 3-2) at which the depth of contamination is uncertain It is known that the contamination exists in the first 15 feet under the ground

surface but below that contaminant levels are unknown In order to meet RCRA guidelines concerning acceptable levels of contaminants left on-site and to establish conservative cost estimates it was assumed that the contamination reached all the way down to the groundwater level or a

distance of approximately 40 feet Excavating or aerating down 40 feet in a loose sandy soil such as at McKin is a potentially expensive task

Therefore another alternative was considered which would consist of aerating or landfarming Areas IB 4 and 5 as described above but placinga

cap as described in Section 343 over Area 3 This alternative would achieve essentially the same remedial affects as the full aeration alternative but might save sufficient construction costs to make it an attractive alternative

3-20

i

348 Excavation and Off-Sfte Renovation

This alternative is similar to the on-site renovation alternative except t with this option the soil is excavated and trucked to a municipal landfill

_where it would be aerated to 5 ppb HNu levels and used for landfill cover material

The aeration would occur in a plastic lined excavated pit in order to contain any leachate which would be created from precipitation during the aeration process As with the on-site renovation a tractor mounted rototiller would be used to aerate the soil A one foot layer of sand will be placed over the plastic liner to protect the liner during the tilling

As with the on-site alternative it is anticipated that 2 till ings will be required before the contaminant concentrations decrease to below acceptable

limits Upon completion of the aeration the soil would be stockpiled for future use as cover material Should it rain during the aeration process

the soil would be allowed to dry before being removed from the lined pit thereby eliminating any need for leachate treatment

The odor produced and release of the volatile organics to the atmosphere during the aeration process are the primary adverse impacts associated with this alternative

These impacts can be mitigated by placing the off-site aeration location in

an area remote from populated areas This would allow the organics to disperse prior to migrating over inhabited areas Due to the political

concerns no acceptable off-site aeration and disposal site has been identified at this time For the purposes of cost comparison it is assumed

that one of the adjacent towns within a 20 mile radius will allow the aeration to occur at their municipal landfill site

As with the on-site aeration alternative the volatile emissions during

excavation and off-site aeration would be monitored Should action limits be exceeded the aeration process would be shut-down until safe levels were

reestablished

3-21

Once again the low cost and relatively simple mechanical equipment involved

are the main advantages of this alternative

35 Off-Site Control Remedial Alternatives

351 No Action

The No Action alternative if chosen as an off-site control would have the

same impact and ramifications as the source control No Action alternative (see Section 341) and therefore for the same reasons as outlined before

the No Action off-site alternative is eliminated from further

consideration

352 No Action With Monitoring

The off-site control alternatives are associated with the groundwater that flqws under the site and that has become contaminated due to precipitation leaching the volatile organics out of the soil and into the groundwater

The groundwater and surface water testing completed in the area has shown f

that the groundwater is contaminated only with TCE anl 11-trichloroeshy

thane up to 4500 feet away where the groundwater surfaces at Boiling

Springs The No Action alternative would allow the contaminated

groundwater to continue to travel from the site toward the Royal River which based on monitoring data does not contain any volatile organic

contamination The No Action With Monitoring alternative would require the

provision for the public water system to service both the adjacent homeowners and any new construction in the area

The main consideration in evaluating the No Action With Monitoring alternative is the fact that the contaminated groundwater has already

entered the bedrock aquifer Currently there are no feasible techniques for removing contaminated groundwater from fractured bedrock Therefore

regardless of which off-site control remedy is implemented natural cleansing of the bedrock aquifer is the only feasible contaminant removal

technique

3-22

t

|

Over the long term precipitation and uncontaminated groundwater from the

regional flow field will flush the contaminants and cleanse the aquifer system naturally assuming the source of contaminants is eliminated It

has been predicted by Gerber that once the contaminant source is eliminated

it will take approximately 25 years for the surficial aquifer to cleanse

-itself to less than 10 ppb 111-trichloroethane and within 6 years the bedrock contamination will be less than 1 ppb The required monitoring

would be equivalent to that proposed in that for the on-site control No Action With Monitoring alternative

In order for this alternative to be approved by the EPA for final impleshy

mentation it must be shown that this alternative is essentially in comshy

pliance with current RCRA regulations The pertinent RCRA regulations

state that no contaminated groundwater can leave the site boundaries unless

that contamination is less than EPA primary drinking water standards or an

alternate concentamption limit (ACL) has been established No EPA primary drinking water standard has been set for the specific groundwater contamishy

nants at the McKin site and realistically ACLs have been approved only where there is no feasible technical alternative available for clean-up

Therefore EPA acceptance of this alternative cannot be expected at the

McKin site

353 Pumping and Treating Groundwater

The proposed system is based upon the installation of interceptor or

withdrawal wells with the collected contaminated groundwater being treated and then discharged back to the soil surface directly on top of the

contaminated areas This process would accomplish two purposes First it would intercept the contaminant plume minimizing the transport of the

contaminants beyond the wells and thereby allowing the downgradient aquifer to cleanse itself Secondly the treated groundwater would also act as a

flushing agent that would hasten the natural cleanup of the contaminated

soil and aquifer This alternative should be viewed as the RCRA complying

off-site alternative as the level of treatment appears to meet RCRA requirements

3-23

imlaquoamwj

McKIN SITE GRAY MAINE CAMPOHeMEftAMcKKMC NINFERRED SURFICIAL AQUIFER PLUME FROM GERWER ( 1994 ) On Claquonllaquor Plu Boclon MaraquoMchuMltU 02 1 OS

FIGURE 3-4

The location of the withdrawal wells is a most important consideration with this remedial alternative Due to the extensive size of the contaminant plume (See Figure 3-4) there is no one well location which will meet all the desired results Figure 3-4A has been included to illustrate some of the factors involved in choosing withdrawal points If the withdrawal

wells are placed at the downgradient edge of the plume which 1n this case is in the vicinity of Boiling Springs then the withdrawal wells would be

extracting large quantities of slightly contaminated groundwater The groundwater would have to be treated and then disposed of probably to the

Royal River This would require a NPDES discharge permit Also it has been determined through Gerbers modeling that the contamination if

allowed to leave the site unchecked would very quickly enter the fractured bedrock adjacent to the site and essentially become unextractable and untreatable The nature of fractured bedrock establishes specific pathways or channels by which the contaminated groundwater disperses Therefore for any bedrock aquifer withdrawal well to successfully extract contaminated groimdwater the well and screen must be located exactly in the

desired fracture A deviation of even 1 foot could mean the trough is not intercepted and a dry well is produced There is no existing technology which can be assured of withdrawing groundwater from the contaminated

bedrock aquifer given the degree of accuracy required in well placement

Therefore once the contaminated groundwater reaches the fractured bedrock it is infeasible to attempt to extract it for treatment It should also be

noted that placing the withdrawal wells at the leading edge of the plume allows the contamination to enter the bedrock unchecked

If the point of withdrawal is moved up-gradient toward the site then the extracted groundwater would be more contaminated ie higher concentrashy

tions of contaminants This would make the treatment process more cost-effective but 1t would also allow the down-gradient plume to continue to migrate untreated Also the point of final discharge becomes a concern as you move away from the river

Realistically there are two locations where effluent disposal 1s feasible the Royal River and subsurface disposal on-site As the withdrawal

location is moved further from the river costs associated with disposing

3-25

LEGEND

3) - SOIL BORING LOCATION - WITHDRAWAL WELL LOCATION

- QROUNDWATEft LEVEL - APPROXIMATE TOP OF BEDROCK

WATER SAMPLE ND- BELOW DETECTABLE LEVELS _raquo_ -TAKEN AT DEPTH 1-aodeg 06 ppb 111-TRICHLOROETHANE

1800 ppb TCE

ROYAL RIVER

BOILING SPRINGS-

1000 2000 3000 FEET 4000 6000 6000

McKIN SITE GRAY MAINE CAMP MCSMR McKEE INC

SUBSURFACE CROSS-SECTION A-A FROM SITE TO ROYAL RIVER One Center Plazc Boston Massachusetts 02106

(see Figure 3-4 for Cross-Section Location) FIGURE 3-4A

AREA OF INFLUENCE OF WITHDRAWAL WELL

McKIN SITE GRAY MAINE CAMP MfSSOt McKK MC N GROUNDWATER WITHDRAWAL WELL LOCATIONS SUPERIMPOSED On Center PUu ON INFERRED 111-TRICHLOROETHANE SURFICIAL AQUIFER PLUME BiMton MlaquoraquoMCltuM(U 021 OS

FIQUIIE 3-6

1

of the effluent in the Royal River Increase due to increased pumping length I and associated construction and pumping costs As there is an elevation

difference of approximately 200 feet between the plateau where the site is located and the river valley it is also costly to pump the extracted

groundwater back up to the site for disposal due to pumping distances and elevation differences involved

If the withdrawal wells are located along the down-gradient or northern perimeter of the site then the contaminant plume would be intercepted prior

to the contaminated groundwater leaving the site and impacting upon residential development Also the plume would be intercepted prior to it

entering the bedrock aquifer The drawback to this location is that the majority of the contaminant plume is located down-gradient of the wells and

would be unaffected by the treatment process Being adjacent to the site also allows for the most cost-effective groundwater treatment and disposal

costs 1 s

The above evaluation of withdrawal well location has determined that the most feasible well location is along the sites northern perimeter Gerber

has determined that four wells as located in Figure 3-5 each pumping 5

gallons per minute (gpm) would intercept the surficial plume leaving the

site prior to it entering the bedrock aquifer RCRA officials have also determined that for this alternative to be in compliance with RCRA

guidelines groundwater pumping should also take place at 2 other locations along the plume These locations include an east-west string of wells across the plume at Well B-l and a north-south string of wells at well B-3 (see Figure 3-5)

The rationale behind the placement of the two additional sets of wells is

as follows The string at B-l will attempt to capture the highly contaminated groundwater which has left the site and is thus unextractable

by the first string of wells Also pumping the bedrock well at B-l will withdraw highly contaminated (see Table 3-1) bedrock groundwater The

string of wells at B-3 will attempt to capture the downgradient edge of the core of contamination as the shallow soil well at B-3 registered a TCE

level of 1800 ppb 1n March 1984 It is also suggested that the bedrock

3-27

well at B-3 also be used as a withdrawal well In order to hasten the

bedrock aquifer cleansing process

The withdrawal wells would have to be installed on private property In order to assure continuous access to the wells for maintenance and monitoring either the property must be purchased from the existing owners or permanent easements obtained

TCE and 111-trichloroethane which were the two groundwater contaminants found are readily removed by an air stripping treatment process Air stripping consists of allowing the contaminated groundwater to come into

contact with large quantities of air The air facilitates volatilizatiorij thereby removing the organics from the groundwater and introducing them to

the atmosphere The Gerber modeling has determined that the average 111-trichloroethane concentration in the groundwater plume at the proposed withdrawaiylocation is approximately 2500 ppb Using the same 40 to 1 TCE to llltrichloroethane ratio observed in samples obtained from monitoring well B-l (see Figure 1-4 and Table 3-1) the estimated TCE concentration is 100000 ppb at the withdrawal wells It is anticipated that the air stripping process with a 100 to 1 air to water ratio can remove 9995 of the TCE and 111-trichloroethane from the extracted

groundwater in order to meet the remedial response criteria of 50 ppb total

combined TCE and 111-trichloroethane concentration A treatability study

will be required during design to develop design criteria and establish effluent quality In addition a pump test will be required at each

pumping location to evaluate the potential for plume extraction

The ambient air exposure guidelines established by the State of Maine Bureau of Health see Table 3-2 require that the exhaust air be filtered prior to discharge to the atmosphere It Is proposed that a vapor phase carbon filter be used to obtain the required air emission quality Both

TCE and 111-trichloroethane are easier to filter out of air or vapor (hence vapor phase filters) than when in solution with groundwater (liquid

phase filters) The spent carbon filter will have to be disposed of off-site as a hazardous waste at a secure off-site landfill

3-29

TABLE 3-1

LABORATORY ANALYTICAL RESULTS OF GROUNDWATER QUALITY MONITORING

Location

B-l (shal low soil)

B-l (bedrock)

B-2 (shallow soil )

B-2 (deep soil)

B-2 (bedrock)

B-3 (shal low soil )

B-3 (bedrock)

B-4 (deep soil )

B-5 (deep soil )

B-5 (bedrock)

Date (1984)

321

321

322

322

322

320

320

321

320

316

111 Trichloroethane (ppb)

170 (230)

470 (500)

9

16

5

65

3

ND

ND (ND)

7 (8)

Trichloroethylene (TCE) (ppb)

16000

29000

91

160

56

1800

120

ND

ND (ND)

190 (177)

duplicate ND = not detected

These samples were diluted for the analysis of trichloroethylene The companion results in parentheses for 111-trichloroethane are for the undiluted sample

3-30

TABLE 3-2

Estimated Air Stripping Air Emission Concentrations

Estimated Air Stripping Expected Air

Emission Concentration Maine Ambient Concentration After Carbon Air Exposure

Contaminant Prior to Filter Filter1 Guidelines

111-trichloroethane 249-37 mgnT lt0001 mgnf 63 mgm

Trichloroethylene 9960-1474 mgm 004-0006 mgnf 092 mgm

Range is due to wnge in concentration of groundwater as a result of blending groundwater extracted at different points The high values are associated n^tti extracting groundwater at one point closest to the site The low values are associated with extracting groundwater at 3 locations

Based on 1300 Threshold Limit Value (TLV)

3-31

The air stripping creates a saturated air mist and therefore does not function well during freezing weather as the ice buildup makes the stripping column ineffective In order to eliminate that problem a heated enclosure can be constructed around the facility or the treatment facility can be operated seasonally during the non-freezing periods The seasonal option was eliminated due to possible extended periods of cold weather significantly affecting the effectiveness of the aquifer clean-up process

The facility enclosure along with the treatment facility should be temporary such that it can be dismantled and removed off-site at the end of the treatment period The enclosure should also contain sufficient

dehumidification equipment to allow for a moisture-free operating environment for the facilitys electrical and mechanical equipment

The groundwater treatment and recharge process would continue until the analyses of the groundwater withdrawn from the wells has contaminant levels below those levels established as remedial response criteria It is simulated by Gerber that the 111-trichloroethane concentration in the aquifer should decrease below 100 ppb within 5 years following site capping

and below 50 ppb after 10 years therefore it is anticipated that f

withdrawal pumping would hasten the cleanup process significantly For t

cost estimating purposes it is estimated that withdrawal pumping will

shorten the cleanup period to 5 years

353 Provision for Public Water Supply

In 1978 the Town of Gray extended its public water supply to service those

residents near the site whose wells were contaminated This proposed

alternative provides that public water would be supplied to all new

development which may be impacted by the contaminated groundwater plume as

shown in Figure 3-3 and that a Town regulation shall be established to

require connection to the public water supply in lieu of domestic wells for

these new homes within the contaminated area The costs incurred to extend

the water system would be borne by either the Town of Gray or the indivishy

dual developers or builders The extent of the public water system

currently in place is shown in Figure 3-6

3-32

EXISTING DUCTILE IRON WATER MAIN

FUTURE DEVELOPMENT

McKIN SITE GRAY MAINE CAMP DRESSER ft McKEC INC

V On Center Plaza PUBLIC WATER SYSTEM IN VICINITY OF SITE Boston Massachusetts 02 1 06 AS OF JANUARY 1984 FIGURE 3-6

In order to estimate the potential for future residential development in the contaminated groundwater area we contacted the Gray Town Assessor Mr

John Clark Mr Clark indicated that most of the additional development expected in the near future would occur as strip development along the

existing town roads This type of development would not require the construction of additional water mains but would require the installation

of water service connections

The Town Assessor further stated that several of the large parcels of land overlying the contaminated aquifer may be subdivided into residential

building lots within the next ten years Should this occur the existing Town water system would have to be extended by the Town or developer The

two potential subdivisions one located across Mayall Road from the site and the second located west of the Mayall Road-Depot Road intersection and north of the active gravel pit off Depot Road (see Figure 3-6) are estimated to require approximately 3300 feet of water main construction For the purposes of this analysis it is assumed that this potential development will occur ten years in the future

Off-site remedial pump and treat alternatives will resuft in 111shytrichloroethane levels of 10 ppb in the aquifer syste^i for up to 25 years This level of 111-trichloroethane contamination is also an indication of

trichloroethylene contamination as determined in the RI report (see Table 7-9 in the RI report) Analysis of the groundwater obtained from the monitoring wells located downgradient of the wells showed that the ratio of TCE to 111-trichloroethane concentrations varied for any given well sample from 101 to 701 with the average being approximately 351 Therefore a 111-trichloroethane level of 10 ppb would indicate a trichloroethane concentration in the groundwater of approximately 350 ppb This level of contamination is above the State of Maine Maximum Exposure

Guideline (MEG) for TCE which is 45 ppb

This level of contamination is unacceptable in domestic water supplies Therefore the provision for public water supplies is incorporated into

each off-site alternative with the exception of the Restriction of Future Development alternative

3-34

354 Restriction on Future Off-Site Development

This alternative does not involve any capital expenditures or the implementation of any remedial technologies This alternative requires the Town of Gray to restrict future development in any areas which would be affected by the contaminated groundwater plume It is proposed under this alternative that the restricted area be the area as shown in Figure 3-1A which was defined by a 2000 foot buffer or restricted zone around the inferred contaminated bedrock plume Restricting development would

preclude the need to provide public water to the new developments It would also eliminate the development of contaminated water supply wells in the area

This alternative would not hasten the cleansing of the contaminated aquifer The major impact would be to landowners in the contaminated area who could not realise the complete economic benefits of their property due to the restriction^ the land could only be sold as undevelopable property

and therefore significantly reduced in value The town would also be

impacted due to the loss of potential property tax revenue As stated above it is estimated that this restriction would have to remain in place

for approximately the next 25 years unless it was implemented along with other remedial actions It is suggested that 3 consecutive annual water samples taken at Wells B-l B-3 B-4 and B-5 resulting in each we l l s total volatile organic level being less than 50 ppb would be acceptable grounds for lifting the development restriction

36 Summary of Alternatives

The alternatives which will be considered during the second phase of the screening process have been separated into two groups (1) source control

remedial alternatives and (2) off-site control remedial alternatives These are listed for review in Table 3-3

3-35

TABLE 3-3

Summary of Remedial Alternatives

Source Control

1 No Action with monitoring

2 Capping of contaminated soil areas

3A Excavation of contaminated soil with off-site landfill disposal

3B Excavation of contaminated soil with off-site incineration

4 On-site incineration of contaminated soil with on-site landfill ing

5A On-site aeration and landfill ing of contaminated soil

5B Off-site aeration and landfill ing of contaminated soil

5C On-site aeration and capping of contaminated soil combination

Off-Site Control

6 No Action with monitoring

7 Withdrawal wells with groundwater treatment apd on-site recharge bull

8 Restriction on future development

3-36

CHAPTER 4

ANALYSIS OF REMEDIAL ACTION ALTERNATIVES

41 Introduction

The remedial alternatives were categorized into on-site or source control

remedial alternatives and off-site control remedial alternatives The purpose of this chapter is to evaluate the two groups of alternatives in order to determine which on-site and off-site control alternatives are most

cost effective Due to the impracticability of implementing off-site control

measures without first controlling on-site contamination it was assumed

during this analysis that each of the off-site control alternatives except shy

the No Action alternative would be accompanied by on-site source control

Alternatives 1 through 8 were evaluated against both cost and non-cost criteria The non-cost criteria as previously discussed include

a Reliability

b Implementability

c Operation and Maintenance Requirements

d Environmental Impacts

e Safety Requirements

The cost and non-cost analyses are presented in Sections 42 and 43

42 Non-Cost Analysis

Tables 4-1 and 4-2 were developed to summarize the findings of the non-cost

analysis

43 Cost Analysis

The costs both capital and OampM costs to Implement each alternative are

presented in Tables 4-3 through 4-14 Table 4-15 shows a summary of the

capital and 04M costs associated with each alternative

4-1

TABLE 4-1 SOURCE COHTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE

(SOURCE CONTROL)

1 It) Action wMonitoring

2 Cap Hot Spots with synthetic membrane

3A Limited Excashyvation with off-site disshyposal at landshyfill

(

ENVIRONMENTAL CONSIDERATIONS

Continued migrashytion of contamishynated ground shywater Indefishynite dependence on public water supply Will reach steady state by 1990

Groundwater 20shy30 below contamshyinated soil Grading and capshyping will have minimal impact on local environshyment Contamishynants In groundshywater would be reduced to less than 50 ppb after 10 years

Site would require regradlng after excavation Potential for contaminating environment during transshyportation

TECHNICAL CONCERNS

Groundwater monishytoring program would be adjustshyed as a result of on-going testshying

Boundary of conshytaminated soils must be accurateshyly defined Gradshying must insure against tearing of membrane Tight joints must be maintained 50 year 1 1 f e of membrane assumed

Boundary of conshytaminated soils must be accurshyately defined Each load of contaminated soil removed from site must be characterized

OPERATION AND HEALTH AND MAINTENANCE SAFETY

RELIABILITY IMPLEMENTABILITY REQUIREMENTS CONSIDERATIONS OTHER

Not Applicable Difficult due to Periodic (quar- Continued contam- Existence of public concern Would require off-site control

terly until modified) sampling of 4

ination of groundshywater by contamishynated soils reshy

public water reshyduces impact on existing home-

measures for at least 25

on-site moni- tor ing wells

maining on-site Current air emisshy

owners

years Lab analysis for volatile organics

sions do not meet Maine guidelines Emissions would conshytinue to occur

With proper In- Low level of Inspections to Groundwater stilt Temwrary noise stallation very reliable

technology reshyquired Would meet RCRA requireshyments No permits

assure cap Inshytegrity from burshyrowing animals or catastrophic

contaminated Significant short term exposure to workers during

Impacts during grading of soil Future use of site must take

required otherthan EPA and DEP

events mowingseeded area and

capping into account burshyled membrane

approval removing shrubs and seedlings

which will reshystrict excavation in areas of conshytamination

No dependence Low level of tech- Mowing seeded Eliminates genera- Temporary noise on mechanical nology required area and removing tion of future and traffic imshydevices other Would meet RCRA shrubs and seedshy on-s1te health pacts during ex-than excavation and hauling

requirements Ex-Xavated soil would

llngs concerns Groundshywater still conshy

cavation and reshygrading

equipment have to meet landshy taminated fills permit reshyquirements

Significant short term exposure to workers during excavation Potential for air contamination In vicinity of site during excavation Transfers health hazard to off-site area

Both on-site and background concentrations are above Maine Ambient Air Exposure Guidelines for TCE

TABLE laquo-l SOURCE CONTROL - SUMMARY OF NON-COST ANALYSIS (Contd)

OPERATION AND ENVIRONMENTAL TECHNICAL MAINTENANCE CONSIDERATIONS CONCERNS RELIABILITY IMPLEMENTS IL 1TV REQUIREMENTS

Same as Alt 3A Same as Alt 3A Must rely on In- Must be Able to 0 A M of Incinshyexcept that an cinerator to reclassify erator must main-EPA and state maintain permit- incinerator tain permitted permitted incin- ted status Re- residue is being status (MM erator must be maining process non-hazanious costs to be In-used reliable otherwise Alt d- fluded in dis-

faults to Alt lal capital 3A (see OTHER) costs

Same as Alt 3B Incinerator stack Same as Alt 3B Must be able to Temporary OHM emissions must reclasslfy associated with meet permitted incinerator portable Inclnshylevels Boundary resldue as being erator 0 M of contaminated non-hazardous costs to be In-soil must be ac- otherwise Alt eluded In portshycurately defined not economically able Inclnerashy

feaslble tor capital costs

Monitoring of Boundary of con- Sane as Alt 3A Low level of Same as Alt 3A aeration plume laminated soil mechanical required must be accur- technology re-Same contami- ately defined quired Wouldnant reduction Determination of require reclasslfyshyrate as with acceptable levels Ing soil AH Signi- of residual con- prior to backshyficant odors tamination so as filling Public produced to establish end concern would be

of aeration pro- high No other cess permits required

other than EPA and DEP approval

Saw as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 5A Same as Alt 3A with public conshycern being higher as aeration of soils will have to be accepted by public other than those adjashycent to site Public concern of adjacent homowners should be less Would require DEP ruling that aerated soil Is acceptable landfill cover nwtprial (See OTHER)

HEALTH AND SAFETY

CONSIDERATIONS

Same as Alt 3A plus potential for transferlng health hazard to off -site area in terms of air contamination

Sam as Alt 3A except final disposal poses no health risk

Grounowater still contaminated Significant short term exposure to workers during excavation and aeration Potenshytial hazard to residents duringaeration Addishytional analysisrequired

Same as Alt 5A except aerationwould occur in remote area with minimal Impact on adjacent resishydents

OTHER

Not practical to Implement due to rpstrictivepackaging reshyquirements and associated costs

Temporary noiseduring excavatingbackfilling and regrading

Bowl -shaped site surrounded by trees may require blowers and pipe stack to disperse aeration plumeTemporary noiseduring excavation backfilling and grading

Extremely difficult to Imshyplement due to political conshycerns In findingoff-site location Assumes remote area within 20 mile radius of Gray

3B

laquo

5A

i oo

5B

ALTERNATIVE

Limited exshycavation with off -site disposalat incinshyerator

Limited exshycavation with on-site Incinshyeration and disposal

Limited exshycavation with on-site aeration and disposal

Limited exshycavation withoff-site aeration and disposal

5C On-S1te Same as Alt 5A Same as Alts 2 Same as Alt 3A Same as Alts Same as Alt 2 Same as Alt 5A Combination of bull raquoH Kft Alt 2 and 5A

TABLE 4-2 OFF-SITE CONTROL - SUMMARY OF NON-COST ANALYSIS

ALTERNATIVE ENVIRONMENTAL CONSIDERATIONS

TECHNICAL CONCERNS RELIABILITY IMPLEMENTABILITY

OPERATION ANDMAINTENANCE

REQUIREMENTS

HEALTH AND SAFETY CONSIDERATIONS

(Off -site Control)

6 No action with monitorshy

Same as Alt 1 Same as Alt 1 Not applicable Same as Alt I Same as Alt 1 Same as Alt 1

i -p

7 Withdrawal wells treatshyment and inshyjection of treated groundwater 1n conjuncshytion with public water

Bedrock aquifer and downgradlent surficial aquifer remain contaminashyted Eliminashytion of contamshyinant source will allow natural cleans-of aquifer to occur

Location depth and pumping rate of wells must be accurate for maximum capture of contaminated groundwater Air emissions and effluent standards from water treatment must be estabshyllshed

Requires reliance on well pumps groundwater treatshyment processsubsurface leach-Ing field and municipal water system Permashynent access to wells on private property must be obtained

Treatment process must meet EPA and and DEP air emisshysions and effluent standards Public concern may be high due to air emissions and location of wells In residential area

Pumping of groundshywater to treatment facility Power labor and chemishycals to operate facility Pump-Ing of effluent to leaching field Anticipated facshyility will be In operation approx 5 years Reshyquires continushying water system 0 ft M

Groundwater will be decontaminated over approx 5 years Health Impacts of any emission plume from treatment system wi11 need further analysis

8 Restriction on future development

Same as Alt 1 None Not Applicable Difficult due to economic hardships placed on landshyowners

None Same as Alt 1

For analysis each off-site control alternative is assumed to be contained with a source control alternative which eliminates source of contamination

OTHER

Same as Alt 1

Implementation will lessen dependency of future development on public water supply Public water must be available prior to habitation of future residences until treatment completed

Value of affected land will decrease due to restricshytions on use

TABLE 4-3

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 1 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments)

Monitoring Well (4) Installation

$

S

0

14000

SUBTOTAL $ 14000

Engineering and Contingencies S 5700

TOTAL $ 19700

OampM COSTS

J TOTAL CAPITAL COST-ESTIMATE $ 30000

Laboratory Analysis of Groundwater Samples

Assumptions

- 4 Monitoring Wells to be sampled for contaminants

- Full Groundwater Monitoring Test Analysis $3000Analysis

- 1 Blank and 1 Duplicate Sampleyear

- Full Groundwater Analysis once per year for thirty (30) years

- Quarterly Volatile Organic Scans per well for 3 years

- Semi-annual Volatile Organic Scans per well for years 4 and 5

Based on projected development in area costs to be borne by developers

Includes preparation of construction bid package and 15 contingencies

For cost estimating purposes a practical RCRA Appendix VIII analysis was assumed

No separate volatile organic scans after first 5 year period

4-5

TABLE 4-3 (Cont d)

Annual Costs

Full groundwater analysis (4 wells) $3OOUanalysis $12000year

1 Blank and 1 Duplicate sampleyear

Labor Costs to sample wells (4) 2 daysyear

Subtotal Annual Full Analysis OampM Costs

Additional Volati le Organic Scanning Costs

Years 1-3 3 Add Samplings at $850sample Years 4amp5 1 Add Sampling at $8507sample Years 6-30 Assumed No Volati le Organic

Scan Necessary

COST SUMMARY

Capital Costs

OampM Costs (years 1-3) (years 4amp5) (years 6-30)

r

$ 6000year

$ 1 OOPyear

$19000year

$18300year $ 6100year

$ 0year

$20000year

$37300year $25000year$19000year

Includes labor QAQC samples and analysis to sample 4 wells

4-6

TABLE 4-4 COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 2 - CAPPING HOT SPOTS WITH SYNTHETIC MEMBRANE

j CAPITAL COSTS

Assumptions

i - Area of Contamination to Be Covered 5600 sy

t bull - 40 Mil Synthetic Membrane Covered by 1 Foot Sand Layer and 1 Foot

Loam Cost also includes seeding

- Soil at TP 1A (1 cy) shipped to Alabama at $360load-mile for disposal (conservative cost estimate other disposal alternatives may be less costly at time of cleanup)

Construction Costs

MonitoringWell (4) Installation = $ 14000 Capping 5y600 sy P $919sy = $ 51460 Learning 4 Seeding remaining cleared site (45 acres) - $ 56630 Excavate and dispose of 1 cy from TP 1A = $ 6120

i SUBTOTAL $128210

Engineering and Contingencies bull $ 26830

TOTAL $155040

TOTAL CAPITAL COST - ESTIMATE $155000

OampM COSTS

Groundwater Monitoring (same as Alt 1) 37300 to $19000year

Annual Maintenance (mowing 45 acresliner inspection) (4 timesyear) = $ 1600year

TOTAL ANNUAL 0M COSTS - $38900 to $20600year

Actual contaminated soil laquo 580 sy but covering all hot spots with one cap requires 5600 sy of coverage Soil at TP I1A to be excavated and landfilled off-site

Includes regrading on-site sand under membrane installing membrane regrading on-site sand over membrane placing loam and hydroseeding

Includes preparation of construction bid package final survey of site and 15 contingencies

4-7

TABLE 4-5

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3A - LIMITED EXCAVATION WITH OFF-SITE DISPOSAL AT LANDFILL

CAPITAL COSTS

Assumptions

- Closest Acceptable Landfill - Chemical Waste Management (Emelle Alabama)

- 1700 Miles Gray Me to Emelle Alabama

- $360load-mile

- Soil Density = 100 poundscubic foot

- Excavation requires removal of 12000 cy of uncontaminated soil along with 2700 cy of contaminated soil

- 20 Tons (148 cy) per truck load

Construction Cost

Excavation - 2700 cy $5cy 12000 cy at $ 250cy = $ 43500

Transport (Truck to Landfill) = $1113840

Disposal at Landfill - 3645 tons $100ton f = $ 364500

Loam and seed site s $ 76230 SUBTOTAL $1598070

Engineering and Contingencies 249110

TOTAL $1847180

TOTAL CAPITAL COST - ESTIMATE $1847000

0AM COSTS

Annual maintenance (mowing 4 timesyear) $l600year

TOTAL ANNUAL 0 amp M COSTS bull $1600year

Includes preparation of constructon bid package final survey of site and 15 contingencies

4-8

TABLE 4-6

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 3B - LIMITED EXCAVATION WITH OFF-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Rollins Environmental Services Incinerator Bridgeport NJ (450 Miles)

- Soil Must Be Packed in 40 Gallon Fiber Drums (200 - 40 gal drumstruck)

(Maximum Weight Per Drum = 200 Ibs Max Truck Load = 40000 Ibs)

- Soil Density = 100 Ibscubic foot

Construction euroost

Excavation (See Alt 3A) = $ 43500

Packing of Soil in 40 Gallon Drums = $ 430380

Transport(183 truck loads)to Incinerator $ 295250

Loam and seed site $ 76230

Incinerator Cost (Including Landfill ing of Residue) = $ 3645000

SUBTOTAL $ 4414130

Engineering and Contingencies 671520

TOTAL $ 5086650

TOTAL CAPITAL COSTS - ESTIMATE $ 5087000

OampM COSTS

Annual Mai ntenance( mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL 04M COSTS $ 1600yr

Includes preparation of construction bid package final survey of site and 15 contingencies

4-9

TABLE 4-7

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 4 - LIMITED EXCAVATION WITH ON-SITE INCINERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Mobile Rotary Kiln Incinerator

(Equal to Unit Supplied By M amp S Corporation Conn)

- Kiln Incineration will allow soil to be reclassified as non-hazardous by EPA and DEP

Construction Cost

Excavation - (see AH3A) = $ 43500

Incineration Cost (Including 6 Months OampM) = $13000001

On-Site Landfilling - 2700 cy $5cy = $ 13500

Loam and Seed Site = $ 76230

SUBTOTAL $1433230

Engineering amp Contingencies $ 231580 f

TOTAL $1664810

TOTAL CAPITAL COST - ESTIMATE $1665000

OampM COSTS

The Incineration OampM is included in the Incineration Capital Cost

Annual Maintenance (mowing 4 timesyear) $ 1600yr

TOTAL ANNUAL OampM COSTS $ 1600yr

Includes preparation of constructon bid package design of incinerator pad final survey of site and 15 contingencies

If the EPA Portable Incinerator is available the incineration cost is estimated to be $ 810000

4-10

TABLE 4-8

COSTS ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5A-LIMITED EXCAVATION WITH ON-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassified by EPA and DEP as a non-hazardous waste

- Aeration procedure shall include aerating and skinning off contaminated soils in one foot lifts until all contaminated soil is aerated to below action limits Head space jar analyses also included

- Once aeration is completed soil will be landfilled on-site

V Construction Cost

Air Monitoring Program = $ 10000

Aeration Cost (2 Aerations) $ 84760

Landfilling On-site = $ 6750

Loam and Seed Site bull $ 76230

SUBTOTAL $177740

Engineering and Contingencies $ 34260

TOTAL CAPITAL COST $212OOU

04M COSTS

Annual Maintenance (mowing 4 timesyear)

TOTAL ANNUAL OampM COSTS

Includes preparation of construction bid package final survey of site and 15 contingencies

4-11

TABLE 4-9

COSTS ASSOCIATED WITH SOURCE CONTROL ALTERNATIVE 5B - LIMITED EXCAVATION WITH OFF-SITE AERATION AND DISPOSAL

CAPITAL COSTS

Assumptions

- Aeration of soil will allow soil to be reclassif ied as a non-hazardous waste

- Aerated soil can be used as municipal landfill cover material at no additional incurred disposal cost

- Plastic lined aeration pit (approximately 100x 100 x 18 inches deep) shall be located off-site (assumed to be within 20 miles of McKin Site) and shall consist of a graded pitlined with 10 mil plastic and covered with one foot deep soil cover

Construction Costs

Excavation shy (See Alt 3A) = $ 43500

Transport (Truck) to Municipal Landfill = $ 13180

Plastic Lined Aeration Pit = $ 30240

Aeration Cost (2 Aerations) = $ 32400 Air Monitoring Program = $ 10000

Landfill ing (Assumed Part of Normal Municipal Landfill Operations Cost) f $ 0

Loam and Seed Site f = $ 76230 SUBTOTAL $ 205550

Engineering and Contingencies $ 40010

TOTAL $ 245560

TOTAL CAPITAL COST - ESTIMATE $ 246000

OampM COSTS

Annual Maintenance (mowing 4 timesyear) = $ 1600yr

Political concerns make off-site locations unavailable at this time but it is assumed that a site could be found within a 20 mile radius of the McKin Site

Includes head space jar analyses Aeration costs less than Alt 5A as soil is spread out all in one 18-inch layer

Includes survey of off-site location design of aeration pit preparashytion of construction bid package final survey and 15 contingencies

4-12

TABLE 4-9A

COST ASSOCIATED WITH SOURCE CONTROL

ALTERNATIVE 5C - ON-SITE AERATION AND CAPPING COMBINATION

CAPITAL COSTS

Assumptions

- Contaminated areas IB 4 5 and 6 will be aerated

- Contaminated area 3 will be capped with synthetic membrane

- Same capping assumptions as Alternative 2

- Same aeration assumptions as Alternative 5A

Construction Cost

Air Monitoring = $ 10000 laquof

Aeration Cost Z Aerations) laquo $ 10300

Landfill ing On-Site = $ 1200

Capping Area 3 (1600 sy) = $ 9100

Loam and Seed Site = $ 76230

SUBTOTAL = $106830

Engineering and contingencies $ 23620

TOTAL = $130450

TOTAL CAPITAL COST - ESTIMATE $130000

04M COSTS

Same as Alternative 2 (see Table 4-4)

TOTAL ANNUAL 0AM COSTS $38900 to 20600year

Includes head space jar analyses Includes soil beyond contaminated area to eliminate effects of

precipitation dispersion

4-13

0

TABLE4-10

COSTS ASSOCIATED WITH OFF-SITE CONTROL

ALTERNATIVE 6 - NO ACTION WITH MONITORING

CAPITAL COSTS

Water Main Construction Cost (for future developments) $

Installation of Monitoring Well (W-104)1 $3500

TOTAL CAPITAL COST - ESTIMATE $3500

0AM COSTS

Laboratory Analysis of Groundwater Samples - Same as Alt 1

COST SUMMARY

Capital Costs $ 3500

0AM Costs Years 1-3 - $37300year Years 4amp5 - $25100year Years 6-30- F $19000year

Based on projected development in area costs to be borne by developers

AssumeAssumess ususee of existing B-l B-2 and B-3 wells for downgradient monitoring

4-14

TABLE 4-11

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7A - WITHDRAWAL AND TREATMENT OF GROUNDWATER

AT ONE LOCATION

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- Well pumping rate 5 gpmwell (20 gpm Total)

- Average 1984 well concentrations

o TCE = 100000 ppb o 111-trichloroethane 2500 ppb

- Effluent to ground 50 ppb total combined TCE and 111-t^chloroethane concentration

y - Effluent standards require gt 9995 TCE removal

Construction Costs

Installation of wells (including pumps) =Construction of piping from wells shy 500 ft

at $2Uft to on-site treatment facility =

$ 44400

10000

Groundwater Treatment Facility

Air stripping tower =Vapor phase filters (2) Building (Incl Instrumentation Electrical

Piping and Site Work) Installation of subsurface injection system =

$ 17700 $ 21450

$ 28490 1000

SUBTOTAL $123040

Engineering and Contingencies (35) 43060

TOTAL $166100

TOTAL CAPITAL COST - ESTIMATE $166000

4-15

TABLE 4-11 (Contd)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 37300 Carbon (13200 Ibsyear at $ 350lb) = $ 46200 Power ($008kwhr) = $ 3000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 16600

TOTAL ESTIMATED ANNUAL COST = $163100

First year annual costs As contamination concentration decreases with time OampM costs will also decrease f

t

4-16

TABLE 4-12

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7B - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 2 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5)

- Well pumping rate = 5 gpmwell (40 gpm Total)

- Average 1984 well concentrations

o TCE = 65750 ppb o 111-trichloroethane = 1645 ppb

- Effluent to ground = 50 ppb total combined TCE and 1 1 1-trichloroethane concentration

- Effluent standards require gt 9992 TCE removal

- Easement costs are assumed to be $l000well

Construction Costs

Installation of wells (including pumps) = $ 88800

Construction of piping from wells - 2300 ft at $20ft to on-site treatment facility = $ 46000

Easements (access to wells) $ 4000

Groundwater Treatment Facility

Air stripping tower = $ 21200 Vapor phase filters (2) $ 32200 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 28490 Installation of subsurface Injection system = S 1000

SUBTOTAL $221 690

Engineering and Contingencies (35) 79190

TOTAL $300880

TOTAL CAPITAL COST - ESTIMATE $301 000

4-17

TABLE 4-12 (Cont d)

OampM COSTS

Assumptions

- Groundwater Monitoring required - Pumping to continue 5 years - Facility removed after 5 years - Operating Costs include labor power and carbon

Annual Costs

Groundwater Monitoring = $ 55600 Carbon (17200 Ibsyear at $ 350lb) = $ 60200 Power ($008kwhr) = $ 4000 Personnel (3-8 hr shifts at $20000yr) = $ 60000 Maintenance (10 of Capital Cost) = $ 29400

TOTAL ESTIMATED ANNUAL COST = $209200

First year annual costs As contamination concentration decreases with time OampM costs will also decrease

4-18

TABLE 4-13

COSTS ASSOCIATED WITH OFF-SITE CONTROL ALTERNATIVE 7C - WITHDRAWAL AND TREATMENT OF GROUNDWATER

USING 3 WITHDRAWAL LOCATIONS

CAPITAL COSTS

Assumptions

- 4 wells located across contaminated plume at northern edge of site (see Figure 3-5)

- 4 wells located east-west at B-l (see Figure 3-5) - 5 wells located north-south at B-3 (see Figure 3-b) - Well pumping rate = 5 gpmwell along edge of site and at B-l

100 gpmwell at B-3 Total pumping = 540 gpm - Average 1984 well concentrations

o TCE - 14870 ppb o 111-trichloroethane = 370 ppb

- Effluentto ground 50 ppb total combined TCE and llljrtrichloroethane concentration

- Effluent standards require gt 9967 TCE removal - Easement costs assumed to be $1000well

Construction Costs

Installation of wells (including pumps) = $144300

Construction of piping from wells - 4100 ft at $20ft to on-site treatment facility laquo $ 82000

Easements = $ 9000

Groundwater Treatment Facility

Air stripping tower $ 99500 Vapor phase filters (2) $ 92800 Building (Incl Instrumentation Electrical

Piping and Site Work) $ 45900 Installation of subsurface injection system = $ 2000

SUBTOTAL $475500

Engineering and Contingencies (35) 1163300

TOTAL $638800

TOTAL CAPITAL COST - ESTIMATE $639000

4-19