SULTRAC - REMEDIAL ALTERNATIVES … Assignment No. : ... TCH Thermal conduction heating ... Remedial Alternatives Screening Technical Memorandum Copley Square Plaza Site

REMEDIAL ALTERNATIVES SCREENING

TECHNICAL MEMORANDUM

FOR

COPLEY SQUARE PLAZA SITE – OPERABLE UNIT 2

COPLEY, SUMMIT COUNTY, OHIO

Prepared for

U.S. Environmental Protection Agency

Region 5

77 West Jackson

Chicago, Illinois 60604

Work Assignment No. : 157-RICO-05XW

Contract No. : EP-S5-06-02

Date Prepared : November 25, 2014

Prepared by : SulTRAC

SulTRAC Project Manager : Stan Lynn

Telephone No. : (513) 333-3667

EPA Work Assignment Manager : Margaret Gielniewski

Telephone No. : (312) 886-6244

Remedial Alternatives Screening Technical Memorandum Copley Square Plaza Site – Operable Unit 2 157-RICO-05XW November 2014

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CONTENTS

Section Page

ACRONYMS ............................................................................................................................................... v

1.0 INTRODUCTION ........................................................................................................................... 1

1.1 SITE BACKGROUND AND HISTORY ................................................................................................................ 2 1.1.1 Site Description ........................................................................................................................................ 2 1.1.2 Site History ............................................................................................................................................... 2

1.2 SITE REMEDIAL INVESTIGATION SUMMARY ................................................................................................ 3 1.2.1 Site Geology ............................................................................................................................................. 4 1.2.2 Site Hydrogeology .................................................................................................................................... 5

1.2.2.1 Groundwater Flow Direction/Horizontal Hydraulic Gradients ....................................................... 7

1.2.2.2 Vertical Hydraulic Gradients ........................................................................................................... 7

1.2.2.3 Groundwater Flow Velocity ............................................................................................................ 7

1.2.3 Nature and Extent of Contamination ....................................................................................................... 8 1.2.3.1 RI COCs Data – July 2012 to April 2013 ........................................................................................... 9

1.2.3.2 RI MNA Data – July 2012 to April 2013 ......................................................................................... 10

1.2.3.3 Supplemental RI Data – October 2013 .......................................................................................... 10

1.2.3.4 Supplemental RI Data – January 2014 .......................................................................................... 12

1.2.4 Human Health Risk Assessment ............................................................................................................. 13

1.3 REPORT ORGANIZATION ............................................................................................................................ 14

2.0 IDENTIFICATION OF RAOS, ARARS AND AREAS AND VOLUMES REQUIRING

REMEDIATION FOR OU#2 GROUNDWATER ................................................................................. 15

2.1 REMEDIAL ACTION OBJECTIVES ................................................................................................................. 15 2.1.1 RAOs for OU#2 Groundwater ................................................................................................................ 15

2.2 ARARs ......................................................................................................................................................... 16 2.2.1 Overview of ARARs ................................................................................................................................ 16 2.2.2 Chemical-Specific ARARs and TBCs ........................................................................................................ 19 2.2.3 Action-Specific ARARs ............................................................................................................................ 19 2.2.4 Location-Specific ARARs......................................................................................................................... 19

2.3 AREAS AND VOLUMES THAT REQUIRE REMEDIATION ............................................................................... 19 2.3.1 Groundwater ......................................................................................................................................... 19

2.4 ASSUMPTIONS ............................................................................................................................................ 20

3.0 GENERAL RESPONSE ACTIONS FOR OU#2 GROUNDWATER ..................................... 21

3.1 GRAs, TECHNOLOGY TYPES AND PROCESS OPTIONS FOR OU#2 GROUNDWATER .................................... 21 3.1.1 No Action ............................................................................................................................................... 21 3.1.2 Institutional Controls ............................................................................................................................. 21


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3.1.3 Containment .......................................................................................................................................... 22 3.1.4 Treatment .............................................................................................................................................. 22 3.1.5 Monitored Natural Attenuation............................................................................................................. 22

4.0 PRELIMINARY SCREENING OF REMEDIAL TECHNOLOGIES AND GRAs ............... 23

4.1 SCREENING CRITERIA.................................................................................................................................. 23 4.1.1 Effectiveness .......................................................................................................................................... 23 4.1.2 Implementability .................................................................................................................................... 23 4.1.3 Cost ........................................................................................................................................................ 24

4.2 EVALUATION OF GRAs AND PROCESS OPTIONS FOR OU#2 GROUNDWATER ............................................ 24 4.2.1 No Action ............................................................................................................................................... 24 4.2.2 Institutional Controls ............................................................................................................................. 24 4.2.3 Containment .......................................................................................................................................... 25 4.2.4 In Situ Groundwater Treatment ............................................................................................................ 27 4.2.5 Monitored Natural Attenuation............................................................................................................. 32

4.3 SUMMARY OF RETAINED PROCESS OPTIONS ............................................................................................. 33

5.0 DEVELOPMENT OF REMEDIAL ALTERNATIVES ........................................................... 34

5.1 DESCRIPTIONS OF ALTERNATIVES FOR OU#2 GROUNDWATER ................................................................. 35 5.1.1 Groundwater Alternative 1 – No Action ................................................................................................ 35 5.1.2 Groundwater Alternative 2 – Institutional Controls and MNA .............................................................. 36 5.1.3 Groundwater Alternative 3 – In Situ Treatment .................................................................................... 37

5.1.3.1 AS/B ............................................................................................................................................... 38

5.1.3.2 Chemical Reduction ...................................................................................................................... 39

5.1.3.3 Enhanced Bioremediation ............................................................................................................. 40

5.2 COMPARISON OF ALTERNATIVES TO NCP CRITERIA................................................................................... 42


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FIGURES

Figure

Figure 1 Site Location Map

Figure 2 Site Features Map

Figure 3 Quarterly PCE Isoconcentration Contour Maps

Figure 4 Quarterly TCE Isoconcentration Contour Maps

Figure 5 Quarterly Cis-1,2-DCE Isoconcentration Contour Maps

Figure 6 Quarterly VC Isoconcentration Contour Maps

Figure 7 3-Dimensional PCE Groundwater Plume

APPENDICES

Appendix

A Distribution of COCs Concentrations in Groundwater

B Summary of Potential ARARs

C Preliminary Screening of General Response Actions, Technology Types, and Process Options


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ACRONYMS

µg/L Micrograms per liter

ARAR Applicable or relevant and appropriate requirement

AS/B Air sparging/biosparging

bgs Below ground surface

CAA Clean Air Act

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

cm/s Centimeters per second

COC Contaminant of concern

CWA Clean Water Act

DNAPL Dense nonaqueous phase liquid

DCE Dichloroethene

DDC Danton Dry Cleaners

EPA U.S. Environmental Protection Agency

ESI Expanded site inspection

FS Feasibility study

ft/ft Feet per foot

GRA General response action

HHRA Human health risk assessment

MCL Maximum contaminant level

MNA Monitored natural attenuation

msl Mean sea level

NCP National Oil and Hazardous Substances Pollution Contingency Plan

NPL National Priorities List

Ohio EPA Ohio Environmental Protection Agency

O&M Operations and maintenance

ORP Oxidation/reduction potential

OU Operable unit

PCE Tetrachloroethene

PRG Preliminary remediation goal

RAC Response Action Contract

RAO Remedial action objective

RCRA Resource Conservation and Recovery Act

RI Remedial investigation

SDWA Safe Drinking Water Act

SI Site inspection

SL Screening level

SLERA Screening level ecological risk assessment

SVE Soil vapor extraction

TBC To be considered

TCH Thermal conduction heating

TEF Toxicity equivalency factor

TSCA Toxic Substances Control Act

USDA United States Department of Agriculture

VC Vinyl chloride

VOC Volatile organic compound

WA Work assignment

ZVI Zero-valent iron


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1.0 INTRODUCTION

SulTRAC prepared this remedial alternatives screening technical memorandum for the U.S.

Environmental Protection Agency (EPA) under the EPA Remedial Action Contract No. EP-S5-06-02

(RAC 2), Work Assignment No. 157-RICO-05XW. Under this work assignment, EPA tasked SulTRAC

to prepare a technical memorandum presenting the development and screening of potential remedial

alternatives for Operable Unit 2 (OU#2) of the Copley Square Plaza site in Summit County, Ohio.

Specifically, SulTRAC developed a list of potential remedial alternatives to address contaminants of

concern (COC) associated with the intermediate and deep groundwater zones (OU#2) at the site. It is

widely recognized that the distribution of dissolved contaminants in groundwater is complex and difficult

to predict, especially in fractured bedrock settings such as the OU#2 site. Research has shown that in-situ

groundwater treatment technologies can more broadly target dissolved contaminants, including dead-end

or reduced accessibility fractures and within the primary porosity of the rock (such as bioremediation or

chemical reduction) and are preferred over ex-situ treatment methods (CLU-IN.org 2014). Based on this

information, the focus of this memorandum is in-situ remediation techniques along with monitored

natural attenuation (MNA), which will be evaluated further after collection of additional groundwater

data. SulTRAC prepared this technical memorandum in accordance with applicable EPA guidance (EPA

1988).

The primary goals of the remedial alternative screening evaluation are to (1) establish site-specific

remedial action objectives (RAO) protective of human health and the environment for OU#2, (2) propose

general response actions for OU#2 by defining actions to satisfy RAOs, (3) screen remediation

technologies and process options to ensure only applicable technologies are considered, and (4) develop a

range of remedial alternatives in accordance with the National Oil and Hazardous Substances Pollution

Contingency Plan (NCP). SulTRAC will screen each alternative for effectiveness, implementability, and

cost. SulTRAC will also include an estimate of areas and volumes of contaminated media at OU#2, as

well as a preliminary identification of applicable or relevant and appropriate requirements (ARAR)

relative to OU#2.

The purpose of this technical memorandum is to establish RAOs, screen technologies and process

options, and develop a list of remedial alternatives that will undergo a full evaluation with respect to

EPA’s established evaluation criteria (EPA 1988). The intent is to reach a consensus with EPA and the

Ohio Environmental Protection Agency (Ohio EPA) on the range of remedial alternatives that will


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undergo full detailed evaluation in the feasibility study (FS) report prior to conducting the detailed

evaluation of alternatives.

1.1 SITE BACKGROUND AND HISTORY

The following sections provide a description of the Copley Square Plaza site and a summary of historical

activities that have been conducted at the site. More detailed information can be found in the remedial

investigation (RI) report for the site (SulTRAC 2014).

1.1.1 Site Description

The Copley Square Plaza Site is located at 2777 and 2799 Copley Road in Copley Township, Summit

County, Ohio (Figure 1). The site spans approximately 86 acres, including the Copley Square Plaza and

the estimated extent of groundwater contamination. The area surrounding the site is both commercial and

residential. The Copley Square Plaza is bordered to the north by a vacant lot and condominium complex,

to the east by undeveloped land and condominium complex, to the south by Copley Road and residential

land, and to the west by commercial businesses and residential land (Figure 2). Sampling of public and

private wells in the area (from 1990 to present) has indicated that local groundwater is contaminated by

VOCs.

1.1.2 Site History

Before it was developed in the late 1950s, the Copley Square Plaza property was an operating cattle farm.

Property cards state that the building located at 2777 Copley Road was built in 1963, and the building at

2799 Copley Road was built in 1965. The 2777 Copley Road building housed a dry cleaning business

from the 1960s until August 1994 under a number of owners, most recently Danton Dry Cleaners (DDC).

Initial identification of the site occurred in April 1990 when a complaint of a water odor was submitted to

Ohio EPA (Weston 2009).

In response to the April 1990 water odor complaint, Ohio EPA initiated sampling of two private

groundwater production wells immediately east of the dry cleaning building. Sample results from the

private wells indicated the presence of chlorinated VOCs, specifically tetrachloroethene (PCE),

trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE) and vinyl chloride (VC) above the Safe

Drinking Water Act Maximum Contaminant Levels (MCL). As a result, Ohio EPA directed the tenants

of the dry cleaners to cease use of the private wells, which were subsequently taken out of service. After


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the affected wells had been decommissioned, Ohio EPA continued investigating surrounding wells from

1991 to 1993, with sample results indicating no contamination attributable to the site.

Further investigation of the site by Ohio EPA in April 1994 revealed wastewater that contained VOCs in

concrete pits beneath the floor of the building. A resulting dye tracer test showed migration of the

wastewater to surface water and groundwater. Subsequently, Ohio EPA sampled nearby residential and

private groundwater wells, and VOC concentrations above MCLs were detected in nine wells. Ohio EPA

then requested removal action assistance from EPA.

In August 1994, Ohio EPA requested EPA to initiate a removal action designed to address any immediate

threats that the contamination posed to local residents. This removal action resulted in installation of

point-of-entry household water treatment systems designed to remove the contaminants from the well

water supplied to affected homes, closure of the eight wastewater tanks at the dry cleaning facility at

Copley Square Plaza, and installation of a shallow groundwater recovery trench and sump system at the

dry cleaning building.

On January 23, 2002, Ohio EPA recommended that the site be brought back into the federal system and

that a site inspection (SI) be completed to determine if an ongoing release of contamination to

groundwater was occurring. Ohio EPA performed the SI in September 2002 and also completed an

expanded site inspection (ESI) in August 2003. The site was listed on the National Priorities List (NPL)

in April 2005.

The site was listed on the NPL, and EPA divided the site into two OUs. Operable Unit 1 (OU#1) includes

soil, shallow groundwater, and vapor intrusion (VI) issues associated with the groundwater contaminant

plume. OU#2 includes the intermediate and deep (bedrock) groundwater contamination. On October 13,

2009, EPA issued a Record of Decision (ROD) for OU#1. The selected remedy for OU#1 consisted of

treating the soil and shallow groundwater using in-situ chemical reduction (ISCR), supplying local

residents on private wells with public water, and installing VI mitigation systems in local residences. The

RA work for OU#1 is ongoing.

1.2 SITE REMEDIAL INVESTIGATION SUMMARY

This section presents a summary of the site geology, hydrogeology, and the nature and extent of

contamination as presented in SulTRAC’s RI report (SulTRAC 2014).


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1.2.1 Site Geology

The site geology can be divided into two main categories: the unconsolidated glacial deposits and the

underlying bedrock. The underlying bedrock can be further categorized into the intermediate bedrock and

the deep bedrock zones, which is the focus of the remedial alternatives screening for OU#2.

The till overlying the bedrock (unconsolidated glacial deposits) in the area is approximately 10 to 20 feet

thick and generally consists of interbedded silt, sand, clay, and gravel. Thin sand layers, ranging in

composition from fine, silty sand to clean fine and medium sands, are interbedded within the till deposits.

These interbedded sands range in thickness from less than 1 foot to approximately 5 feet. Shale

fragments are typically present within the till directly above the bedrock surface (Weston 2008).

The Cuyahoga Group underlies the site, subcropping beneath glacial till. Drilling and geophysical logs

indicate that the Cuyahoga Group is composed of interbedded and interfingering shales, sandstones, and

siltstones. Shales are thinly bedded with horizontal and vertical fracturing, which provides hydraulic

interconnection among the various lithologies. The geophysical logs from the RI showed several

horizontal, vertical, and subvertical fracture intervals. The average depth of the fractures shown on the

logs was about 55.4 bgs, and the average dip angle from the horizontal was about 71.2 degrees. The logs

from the borings also showed moderate fracturing (SulTRAC 2014).

Based on site-specific boring logs, as well as private water well logs, the top of bedrock is encountered

between 10 and 19 feet bgs in the site vicinity. Farther to the east and northeast, along North Plainview

Road, bedrock is encountered from 23 to 65 feet bgs. Bedrock is encountered from 20 to 36 feet bgs in

the area of South Plainview, Appletree, and Greening Roads. The bedrock surface tends to dip toward the

east and southeast (Weston 2008).

The weathered bedrock ranges from approximately 5 to 7 feet thick at a depth of approximately 13 to 20

feet bgs. The bedrock becomes less fractured and more competent at depths of approximately 30 to 33

feet bgs (Weston 2008).

The intermediate bedrock zone is the area of fractured rock, which is typically encountered between the

weathered bedrock zone and deeper more competent bedrock. The intermediate bedrock is composed of a

gray fissile to fossiliferous shale with interbedded layers of micaceous siltstone and very fine sandstone of

the Cuyahoga Formation. Each lithology varies in thickness from less than 1 foot to approximately 6 feet.

Vertical and subvertical fracturing with ferric oxidation and some mineralization was noted throughout


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this zone. The fractures were wet and, in some zones, were filled with saturated silt or clay material

(SulTRAC 2014; Weston 2008).

The deep bedrock zone is the area of competent rock encountered beneath the weathered and fractured

intermediate bedrock. The boundary between the deep bedrock zone and the intermediate bedrock zone is

indistinct and cannot be identified based on the extent of fracturing. However, past geotechnical boring

logs have indicated that fracturing within the bedrock ends at a distinct and definitive lithological contact.

Fracturing readily occurs in upper bedrock lithological units composed primarily of shale with thin

interbedded sandstone. Conversely, the deep bedrock unit is composed of sandstone with interbedded

shale; this unit is more competent and less likely to fracture (SulTRAC 2014; Weston 2008).

1.2.2 Site Hydrogeology

The hydrogeology of the site area is characterized by the presence of three groundwater zones. The

shallow groundwater zone has been identified as potentially being a perched water table within the silty

clay unit (Weston 2008). The site geology can be divided into two main categories: the unconsolidated

glacial deposits and the underlying bedrock. The underlying bedrock can be further categorized into the

intermediate bedrock and the deep bedrock zones (OU#2). To further assess the site-specific

hydrogeological conditions at the OU#2 site, SulTRAC installed monitoring wells in the intermediate and

deep groundwater zones. Figure 2 shows the location of all monitoring wells at the site and surrounding

areas for each groundwater zone discussed below.

Shallow Groundwater Zone

Monitoring well screens were installed in lengths ranging from 9.3 to 22.5 feet bgs to monitor conditions

in the shallow groundwater zone. The saturated deposits are generally encountered just above the contact

between the unconsolidated glacial deposits and the weathered upper bedrock units (Weston 2006).

Hydraulic head within the unconsolidated deposits appears to be higher than the underlying Cuyahoga

Group indicating downward gradients and vertical movement of groundwater from unconsolidated

deposits to the bedrock units. The shallow groundwater zone (unconsolidated glacial deposits) overlying

the bedrock is approximately 10 to 20 feet thick, and generally consists of interbedded silt, sand, clay, and

gravel. Interbedded within the till deposits are thin sand layers that range in composition from fine, silty

sand to clean fine and medium sands. These interbedded sands range in thickness from less than 1 foot to

approximately 5 feet. A discontinuous sandy gravel layer is present southeast of the 2777 Copley Road

building at a depth of approximately 10 feet bgs, and a discontinuous silty sand layer is present directly


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beneath the building. Shale fragments are typically present within the till directly above the bedrock

surface. Shale is thinly bedded with vertical fracturing, which provides hydraulic interconnection.

Intermediate Groundwater Zone

An intermediate groundwater zone exists within the relatively higher fractured portion of the bedrock.

Monitoring wells were installed within the intermediate groundwater zone, with well screens installed at

depths ranging from 17.4 to 56 feet within the fractured bedrock. The intermediate bedrock zone is the

area of fractured rock typically encountered between the weathered bedrock zone and deeper, more

competent bedrock, and is comprised of a gray fissile to fossiliferous shale with interbedded layers of

micaceous siltstone and very fine sandstone of the Cuyahoga Formation. Each lithology varies in

thickness from less than 1 foot to approximately 6 feet. Vertical and subvertical fracturing with ferric

oxidation and some mineralization was noted throughout this zone. The fractures were wet and, in some

zones, were filled with saturated silt or clay material. The weathered bedrock ranges from approximately

5 to 7 feet thick at a depth of approximately 13 to 20 feet bgs. Typically, the intermediate groundwater

zone within the bedrock is moderately fractured, however, the shale and sandstone in the vicinity of

monitoring well MW-3I are less fractured and more competent than other intermediate zone locations.

Deep Groundwater Zone

A deep groundwater zone occurs within the shale and sandstone. Within the deep groundwater zone, well

screens were installed at depths ranging from 32 to 81 feet within the bedrock. The deep bedrock zone is

typically more competent and less fractured than the upper intermediate bedrock zone. The boundary

between the deep bedrock zone and the intermediate bedrock zone is indistinct and cannot be identified

solely on the extent of fracturing; however, geophysical logs and geotechnical boring logs have indicated

that fracturing within the bedrock ends at a distinct and definitive lithological contact (Weston 2008).

Fracturing occurs in upper bedrock lithological units composed primarily of shale with thin, interbedded

sandstone. Conversely, the deep bedrock unit is composed of sandstone with interbedded shale; this unit

is more competent and less likely to fracture.

The following discussion primarily focuses on the hydrogeologic properties of the OU#2 site including

the intermediate and deep bedrock zones.


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1.2.2.1 Groundwater Flow Direction/Horizontal Hydraulic Gradients

Historic and RI data indicate that groundwater flow remains fairly constant in an easterly-southeasterly

direction for the intermediate and deep groundwater zones at the site. In the vicinity of the former site

building, however, groundwater flow is to the southeast in the deep groundwater zone and remains

unchanged even during periods of seasonal variation (SulTRAC 2014).

Horizontal hydraulic gradients were calculated for the intermediate and deep monitoring well pairs during

the RI for OU#2. The horizontal hydraulic gradient for the intermediate groundwater zone is generally

higher than the deep groundwater zone. The average annual horizontal gradient for the intermediate

groundwater zone is 0.0275 feet per foot (ft/ft). The average annual horizontal gradient for the deep

groundwater zone is 0.01875 ft/ft (SulTRAC 2014).

1.2.2.2 Vertical Hydraulic Gradients

Vertical hydraulic gradients were calculated for each monitoring well pair during the RI for OU#2.

Downward vertical gradients were documented at all of the well clusters during the RI. However, upward

hydraulic gradients were also observed at well cluster MW-4 located on site and well clusters MW-19,

MW-20, and MW-22 located south-southeast of the site. An upward gradient was also documented at

well cluster MW-4 during the ESI completed by Ohio EPA in August 2003. The upward gradient

observed at well MW-20 is consistent with the geophysical survey completed during the RI that showed

vertical upward fluid flow (through acoustic televiewer logging) at this location (SulTRAC 2014).

1.2.2.3 Groundwater Flow Velocity

Slug tests were performed on select intermediate and deep monitoring wells to evaluate hydraulic

conductivity within the two bedrock groundwater zones; test results were determined to be consistent with

previous investigation data. The geometric mean of the hydraulic conductivities for the intermediate

monitoring wells is 5.1 x 10-4 centimeters per second (cm/sec). The geometric mean of the hydraulic

conductivities for the deep monitoring wells is 3.8 x 10-4 cm/sec (SulTRAC 2014).


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Using the geometric mean of the hydraulic conductivity and groundwater gradient data collected during

the RI and estimated porosity values, the average linear flow velocities for groundwater in the

intermediate and deep groundwater zones were estimated in accordance with Darcy's Law as follows:

V = Ki/ne

Where:

K = hydraulic conductivity, feet/day

i = hydraulic gradient, ft/ft

ne = effective porosity

Groundwater flow velocity is variable within OU#2, typical of fractured bedrock systems. An average

linear groundwater flow velocity of 73 feet per year was estimated for the intermediate groundwater zone.

This estimate was calculated using a hydraulic conductivity value of 5.1 x 10-4 cm/sec, an average annual

gradient of 0.0275 ft/ft, and an effective porosity value of 0.2 for shale with interbedded siltstone and very

fine sandstone that is fractured.

An average linear groundwater flow velocity of 29 feet per year was estimated for the deep groundwater

zone. This estimate was calculated using a hydraulic conductivity value of 3.8 x 10-4 cm/sec, an average

annual gradient of 0.01875 ft/ft, and an effective porosity value of 0.25 for sandstone with interbedded

shale.

1.2.3 Nature and Extent of Contamination

During the RI, groundwater samples were collected from on-site and off-site monitoring wells during four

quarterly sampling events from July 2012 to April 2013 and these data are summarized below (see

Appendix A). SulTRAC installed six additional monitoring wells (MW-32I, MW-32D, MW-33I, MW-

33D, MW-5I, and MW-7I), as part of a supplemental RI in May and June 2014 (see Figure 2). SulTRAC

also abandoned and replaced wells MW-3I, MW-5D, and MW-7D with 10-foot screens during the

supplemental RI. The supplemental RI data collected in October 2013 and January 2014 are summarized

below (see Appendix A). All data collected during the supplemental RI will be summarized in an

addendum to the FS report.

The groundwater samples were analyzed for target compound list (TCL) VOCs, geochemical parameters

(fixed gases [methane, ethane and ethane], total alkalinity, chloride and sulfate, nitrite nitrogen, nitrate

plus nitrite nitrogen, nitrate nitrogen, total organic carbon [TOC], sulfide, dissolved manganese, and

ferrous iron), and target analyte list (TAL) metals analysis (10 percent only). Analytical results for the

site COCs (including PCE, TCE, cis-1,2-DCE, and VC) in groundwater were compared with human


9

health risk assessment (HHRA) screening level criteria. Specifically, the COCs in groundwater were

compared with the EPA maximum contaminant levels (MCL) and EPA screening levels (SL) for tap

water; however, the MCLs are considered the most relevant screening level to delineate the nature and

extent of contamination. Geochemical parameters were also collected during the sampling events to

evaluate MNA as a sole or partial remedy for OU#2. MNA data will be re-evaluated following collection

of additional groundwater data collected during the quarterly monitoring events and will be summarized

in an addendum to the FS report.

The next four subsections provide summaries of analytical results of samples collected and analyzed

during four recent sampling events. The first sampling event was conducted in July 2012, the second

event in October 2012, the third event in January 2013, and the fourth event in April 2013. More detailed

results of the investigation can be found in the RI report for OU#2 (SulTRAC 2014).

1.2.3.1 RI COCs Data – July 2012 to April 2013

Monitoring well results showed site COCs (PCE, TCE, cis-1,2-DCE, and VC) were detected above

laboratory detection limits at 16 monitoring wells during the four sampling events. EPA MCLs and/or tap

water SLs were exceeded in the following: shallow wells MW-3S, MW-4S, MW-5S, and MW-14S;

intermediate wells MW-3I and MW-4I; and deep wells MW-3D, MW-4D, MW-5D, MW-15D, and MW-

17D during the sampling events. Monitoring well MW-14S consistently contained the highest

concentrations of site COCs, including the following: PCE – 35,000 µg/L (second event), TCE – 1,800

µg/L (fourth event), cis-1,2-DCE – 1,100 µg/L (second and fourth events), and VC – 53 µg/L (fourth

event).

The PCE plume dimensions within the groundwater zones were generally consistent during all four

sampling events (see Figures 3A through 6C). The PCE plume in the deep groundwater zone extends

southeast from the site to well MW-15D, near Meadow Run and Copley Road. The distribution of TCE

for the four sampling events generally remained the same and is similar to the distribution of PCE. The

TCE plume in the deep groundwater zone extends southeast to well MW-15D, near Meadow Run and

Copley Road. The cis-1,2-DCE plume extends beyond the footprint of PCE and TCE in the deep

groundwater zone, with detections found in wells MW-7D (south of Copley Road) and MW-17D (near

South Plainview and Appletree Roads). The dimensions of the VC plume in the shallow and intermediate

groundwater zones remained fairly consistent, with the exception of the fourth sampling event that

showed no detections in well MW-4I. During the first and second events, the VC plume in the deep zone


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extended further southeast to Meadow Run and Copley Road compared to the shallow and intermediate

zones. VC was also detected in well MW-17D located along Appletree Road during the second event.

1.2.3.2 RI MNA Data – July 2012 to April 2013

Biodegradation processes were evaluated for OU#2 in the RI report. The geochemical data will be

collected for four additional quarters to evaluate MNA as a sole or partial process option for OU#2

groundwater. Reductive dechlorination is the most important process for the natural biodegradation of

the more highly chlorinated organic compounds, and occurs under mildly reducing anaerobic conditions

(reduction of electron acceptors nitrate and ferric iron). Complete reductive dechlorination of the less-

chlorinated compounds (cis-1,2-DCE and VC) to ethane occurs under anaerobic sulfate-reducing and

methanogenic conditions. The measured dissolved oxygen and oxidation-reduction potential (ORP) data

revealed that the OU#2 bedrock conditions are more anaerobic compared to shallow groundwater zone at

the site. Negative ORP values were consistently observed in monitoring wells located in the source area

where high concentrations of PCE and TCE were detected. This may be an indicator of reducing

conditions that coincide with the natural biodegradation processes within the plume. The reducing

conditions are characterized by, at a minimum, iron reduction. Sulfate concentrations were consistently

high in most wells, which could limit anaerobic dechlorination.

Highly elevated concentrations of methane may indicate that the substrate is being consumed by

methanogens at the expense of dechlorinating organisms. During the sampling events, methane was

consistently detected at elevated levels in intermediate and deep monitoring wells where PCE and TCE

were detected in the source area, which may be an indicator of reducing conditions in OU#2 groundwater.

Elevated chloride concentrations within the source area wells indicate that dechlorination may be

occurring but other environmental factors could be interfering (such as, road salt). In summary, some

lines of evidence, in accordance with EPA guidelines, indicate that natural biodegradation could be

occurring at the site; however, further data will be collected to support a more definitive conclusion. This

additional data will be important to the evaluation of remedial alternatives that will be discussed further in

the FS report.

1.2.3.3 Supplemental RI Data – October 2013

The groundwater sampling event in October 2013 was the first event following ISCR and enhanced

bioremediation treatment of the shallow groundwater zone (OU#1). Laboratory analysis for the COCs in

shallow monitoring wells in the source area showed significant reductions in concentrations of PCE and


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TCE in wells MW-3S, MW-4S, MW-5S, MW-14S, MW-28S, MW-29S, and MW-30S during this event.

PCE and TCE concentrations decreased between 93 percent and 99 percent at each of these wells

compared to the RI pretreatment results. The PCE results for wells MW-3S and MW-5S were below the

EPA SL and MCL during this event. The TCE results for the same two wells were below the EPA MCL

during this event. Low concentrations of PCE were detected for the first time in downgradient wells

MW-16S (0.29 µg/L) and MW-17S (0.26 µ/L) during this sampling event. PCE may have migrated to

these wells during the treatment injection.

The daughter product, cis-1,2-DCE, decreased in concentration at well MW-3S and increased in

concentrations at wells MW-4S, MW-5S, MW-14S, MW-28S, MW-29S, and MW-30S. Cis-1,2-DCE

was detected for the first time in downgradient well MW-8S (0.34 µg/L) during this event. Cis-1,2-DCE

may have migrated to this well during the treatment injection. The daughter product, VC, showed

increasing concentrations at wells MW-3S, MW-4S, MW-5S, MW-14S, MW-28S, MW-29S, and MW-

30S during the October 2013 sampling event compared to the RI results. These trends indicate that

reductive dechlorination is occurring as a result of the treatment in the shallow groundwater zone, and

that the daughter compounds are being produced from the decay of the parent compounds, resulting in

decreasing levels of PCE and TCE, while the subsequent daughter products increased in concentration at

most wells. Eventually, the daughter products will decrease in concentration as microbial processes

accelerate.

The analytical results for intermediate well MW-4I showed a decrease in PCE (0.36 µg/L) concentration

and an increase in daughter products, cis-1,2-DCE (69 µg/L) and VC (47 µg/L) compared to the RI

results. The deep well MW-4D also showed slightly lower concentrations of PCE and TCE compared to

RI results. This indicates that the OU#1 treatment may be influencing the intermediate groundwater zone

near well cluster MW-4 and, to a lesser extent, the deep groundwater zone in this area. The

concentrations of PCE detected in wells MW-4I and MW-4D were below the EPA SL and MCL during

this event. TCE concentrations were below the EPA MCL for the same two wells during this event. Low

concentrations of PCE were detected in downgradient intermediate wells MW-22I (0.28 µg/L) and MW-

24I (0.27 µg/L) and deep wells MW-17D (0.32 µg/L) and MW-22D (0.35 µg/L) for the first time during

this sampling event. The presence of PCE at these wells may be a result of the treatment injection. The

October 2013 COC results for the remaining intermediate and deep wells were fairly consistent with the

RI results.


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1.2.3.4 Supplemental RI Data – January 2014

Further reductions in concentrations of parent compounds, PCE and TCE, were observed in the source

area during the January 2014 event, when compared to the October 2013 event. Concentrations of

daughter products, cis-1,2-DCE and VC, also decreased in parallel with the decrease in parent compounds

during this event. A substantial decrease in COC concentrations was observed in well MW-14S during

this event compared to October 2013:

PCE decreased from 660 µg/L to 0.82 µg/L (below the EPA SL and MCL)

TCE decreased from 90 µg/L to 1.3 µg/L (below the EPA MCL)

Cis-1,2-DCE decreased from 7,600 µg/L to 220 µg/L

VC decreased from 450 µg/L to 150 µg/L

A low concentration of cis-1,2-DCE (0.32 µg/L) was detected in downgradient well MW-8S, which is

consistent with the October 2013 results.

The analytical results for intermediate well MW-4I showed a decrease in the COC concentrations

including PCE (non-detect [ND]), TCE (1.8 µg/L), cis-1,2-DCE (11 µg/L), and VC (7.4 µg/L) compared

to the October 2013 results. This indicates that the OU#1 treatment may be influencing the intermediate

groundwater zone in this area. The COC concentrations at deep well MW-4D rebounded during this

event compared to the October 2013 event. A low concentration of cis-1,2-DCE was detected in

downgradient intermediate well MW-23I (0.33 µg/L) for the first time during this sampling event, which

may be a result of the treatment injection.

The COC results for intermediate well MW-3I remained consistent with the RI and October 2013 results.

However, the deep well MW-3D showed a decrease in the COC concentrations including PCE (70 µg/L),

TCE (33 µg/L), cis-1,2-DCE (190 µg/L), and VC (3.6 µg/L) compared to the RI and October 2013

results. The January 2014 COC results for the remaining intermediate and deep wells were fairly

consistent with the RI results.


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1.2.4 Human Health Risk Assessment

The risk assessment presented in the RI report for OU#2 is based on the COCs detected during four

quarterly groundwater sampling events (July 2012 through April 2013) (SulTRAC 2014). As discussed

in the HHRA for OU#2, historically a number of private groundwater production wells immediately and

nearby to the east of the Copley Square Plaza site obtained potable water from open boreholes that were

drawing groundwater from both OU#1 and OU#2. As a result of the detection of VOCs greater than

MCLs, affected private production wells were outfitted with point-of-entry household water treatment

systems. During the remedial action for OU#1 in 2013, residents and commercial operations were offered

the opportunity to receive municipal water (obtained from the Upper Cuyahoga River upgradient of the

site). Two commercial properties (2631 Copley Road [Lorantffy Care Center] and 2581 Copley Road

[church property]) remain on private groundwater production wells; however, VOCs have not been

detected at either of these properties. Therefore, the HHRA assumed that there are currently no receptors

utilizing affected areas of OU#2 (intermediate and deep groundwater) as a source of potable water.

The ongoing remedial action for OU#1 addresses soil, shallow groundwater, VI, and ecological risks.

Because OU#1 (shallow groundwater contamination) overlies the intermediate and deep groundwater

contamination (OU#2), VI was not evaluated as an exposure pathway for OU#2. Groundwater

contamination from the intermediate and deep bedrock aquifer (OU#2) is also too deep to present a

hazard to ecological receptors. An expanded screening level ecological risk assessment (SLERA) was

completed during the RI for OU#1 in 2008 (Weston 2008). Therefore, VI and a SLERA were not

evaluated as part of the risk assessment for OU#2.

The two objectives of the HHRA for OU#2 were to (1) evaluate whether the COCs detected in

groundwater pose unacceptable risks to potential current and future human receptors under conditions at

the time of the RI (unremediated conditions) and (2) to provide information to support decisions

regarding the need for further evaluation or action based on current and reasonably anticipated future land

use.

The OU#2 groundwater plume extends southeast from the Copley Square Plaza to the area near the

intersection of South Plainview Drive and Appletree Road, south of Copley Road, a distance of about

2,000 feet (a little less than 0.4 mile). However, the primary area of groundwater contamination extends

in a plume about 200 feet wide (southwest to northeast) from the Copley Square Plaza (near wells MW-3I

and MW-3D) about 600 feet southeast to the intersection of Copley Road and Meadow Run (near well


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MW-15D). Currently, no human receptors are located in the primary area of groundwater contamination

within OU#2 because there are no residences in this area. Potential human receptors include (1) future

residents located in the Meadow Run Condominiums located along the northeast side of the primary area

of groundwater contamination and residential areas located east of the condominiums and south of Copley

Road; and (2) future commercial/industrial workers including the Copley Meadows Condominium

Association, the automotive repair and car wash/detailing complex south of Copley Road, and additional

commercial/industrial properties that are located in the Copley Square Plaza, along Copley Road, and

east-southeast of the primary area of groundwater contamination, north of Copley Road.

Residential risks and hazards are driven by the following COCs: PCE, TCE, cis-1,2-DCE, and VC.

Risks for residents exceeded 1E-04 (the upper end of EPA’s risk range of 1E-06 to 1E-04), ranging from

5E-04 at the most downgradient end of the primary area of groundwater contamination (well MW-15D)

to 4E-03 at the most upgradient end of the primary area of groundwater contamination (wells MW-3I and

MW-3D) (SulTRAC 2014).

Risks and hazards for commercial/industrial workers are about 20-fold less than those for residents.

Commercial/industrial workers risks and hazards are driven by the following COCs: PCE (risks only),

TCE (risks and hazards), and VC (risks only). Risks for commercial/industrial workers are within EPA’s

risk range (1E-06 to 1E-04), ranging from 2E-05 at the most downgradient end of the primary area of

groundwater contamination (well MW-15D) to 1E-04 at the most upgradient end of the primary area of

groundwater contamination (wells MW-3I and MW-3D) (SulTRAC 2014).

1.3 REPORT ORGANIZATION

The report is organized into nine major sections. Section 1.0 provides a summary of historical activities

that have occurred at the Copley Square Plaza site. Section 2.0 discusses the identification of RAOs,

ARARs, and areas and volumes requiring remediation for OU#2 groundwater. Section 3.0 provides

general response actions (GRA) and process options for OU#2 groundwater. Section 4.0 provides a

screening of remedial technology types and process options for treating OU#2 groundwater. Section 5.0

provides the remedial alternatives for OU#2 groundwater. References are located in Section 6.0. Figures

are located after Section 6.0.


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2.0 IDENTIFICATION OF RAOS, ARARS AND AREAS AND VOLUMES REQUIRING REMEDIATION FOR OU#2 GROUNDWATER

Remedial technology and process option screening for the OU#2 site consists of the following six steps:

1. Development of RAOs and ARARs for OU#2 groundwater

2. Estimation of areas and volume of groundwater requiring remediation

3. Development of GRAs

4. Screening of remedial technology types and process options for each GRA to eliminate GRAs

that cannot be technically implemented at the site

5. Development of remedial alternatives

6. Detailed analysis of each alternative

This section identifies RAOs, preliminary ARARs, and estimated areas and volume of groundwater that

will require remediation for the OU#2 site. GRAs, screening of remedial technology types and process

options and developing remedial alternatives are discussed in Sections 3.0 through 5.0, respectively. This

technical memorandum does not include a detailed analysis of each alternative or a comparative

evaluation of the alternatives. That analysis will be presented in the FS report.

2.1 REMEDIAL ACTION OBJECTIVES

As specified in the NCP, RAOs should address (1) contaminants of concern (COC), (2) exposure routes

and receptors, and (3) preliminary remediation goals (PRG). RAOs for OU#2 groundwater are discussed

below.

2.1.1 RAOs for OU#2 Groundwater

COCs detected in groundwater at the OU#2 site include the following VOCs: PCE, TCE, cis-1,2-DCE,

and VC. Groundwater contamination for OU#2 is primarily present in the source area; however

groundwater contamination has also been detected south of Copley Road. Current and potential receptors

include future residents and future industrial/commercial workers. Receptors could be exposed to

contamination in groundwater through ingestion of or dermal contact with groundwater used as a source

of potable water. Potential ecological receptors to groundwater were addressed under OU#1.

The following RAOs have been developed for groundwater associated with the OU#2 site:

Prevent direct contact with or ingestion of groundwater containing PCE, TCE, cis-1,2-DCE, and

VC at concentrations that exceed EPA MCLs or Ohio EPA MCLs (if more stringent than EPA


16

MCLs) as presented in the table below. The MCLs presented in Table 2-1 are also considered

PRGs for OU#2 groundwater.

Cleanup Goals for OU#2 Groundwater

Contaminant MCL (µg/L)

PCE 5.0

TCE 5.0

Cis-1,2-DCE 70

VC 2.0

2.2 ARARs

The following sections present an overview of ARARs and identify ARARs and other chemical-, action-,

and location-specific criteria, advisories, guidance, and proposed standards to be considered (TBC).

2.2.1 Overview of ARARs

Section 121(d)(2)(a) of the Comprehensive Environmental Response, Compensation, and Liability Act

(CERCLA) states that on-site remedial actions must attain a level or standard of control that achieves any

standard, requirement, criterion, or limitation under any federal environmental law determined to be

legally applicable or relevant and appropriate, including, but not limited to, the Resource Conservation

and Recovery Act (RCRA); the Toxic Substances Control Act (TSCA); the Safe Drinking Water Act

(SDWA); the Clean Air Act (CAA); the Clean Water Act (CWA); the Marine Protection, Research, and

Sanctuaries Act; and the Solid Waste Disposal Act.

CERCLA also requires remedial actions to achieve a level or standard of control that meets any

promulgated standard, requirement, criterion, or limitation under a state environmental or facility citing

law that is more stringent than any federal standard, requirement, criterion, or limitation and is legally

applicable or relevant and appropriate.


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Section 121(d)(4) of CERCLA provides for waivers of ARARs under the following six types of

circumstances:

When the remedial action is an interim measure and when the final remedy will attain the ARAR

when it is completed

When compliance with an ARAR will result in a greater risk to human health and the

environment than other options

When compliance with an ARAR is technically impractical from an engineering perspective

When an alternative remedial action will attain the equivalent standard of performance of the

ARAR

When the ARAR is a state requirement that the state has not consistently applied (or when the

state has demonstrated the intent to apply consistently in similar circumstances)

For CERCLA Section 104 Superfund-financed remedial actions, when compliance with the

ARAR will not provide a balance between protecting human health and the environment and

Superfund money is available for response actions at other sites

CERCLA Section 121(e) states that no federal, state, or local permit shall be required for any portion of

any remedial action conducted entirely on site. “On site” is defined as the areal extent of contamination

and all suitable areas in close proximity to the contamination necessary for implementation of the

response action. This exemption applies only to the administrative requirements of the permit. On-site

actions must still comply with the substantive requirements that permits enforce. Substantive

requirements pertain directly to actions or conditions in the environment. Health- or risk-based

restrictions, such as MCLs, technology-based requirements (incinerator standards, and location

restrictions), and those that apply to wetlands are examples of substantive requirements.

Administrative requirements are mechanisms that facilitate implementation of the substantive

requirements of a statute or regulation. Examples of these requirements include approval and issuance of

permits, as well as reporting and recordkeeping requirements.


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The NCP identifies two categories of remedial action requirements: ARARs and TBCs. An ARAR can

be either applicable or relevant and appropriate to a remedial action and may include cleanup standards,

standards of control, and other substantive environmental protection requirements, criteria, or limitations

promulgated under federal or state law. These requirements specifically address a hazardous substance,

pollutant, contaminant, remedial action, location or other circumstance at a site.

TBCs include other federal and state criteria, advisories, guidance and proposed standards that are not

legally binding but may provide useful information or recommended procedures. For example, a TBC

can be used to set cleanup levels when no ARAR exists for a specific situation or when an existing ARAR

does not ensure protectiveness. TBCs generally fall within the following four categories:

Health effects information

Technical information

Policy requirements

Proposed rules and regulations

Potential federal and state ARARs for the OU#2 site are listed in Appendix B.

The ARARs are divided into the following three categories as defined in the revised NCP:

Chemical-specific requirements

Action-specific requirements

Location-specific requirements

Chemical-specific ARARs are usually health- or risk-based requirements, often expressed as numerical

values that, when applied to site-specific conditions, establish the acceptable amount of a chemical that

can be detected in or discharged to the ambient environment. Action-specific ARARs are usually

technology- or activity-based requirements triggered by the remedial activities selected to accomplish a

remedy, such as capping, incineration, air stripping or other remedies. Location-specific ARARs include

requirements that place restrictions on either the concentrations of hazardous substances or on the conduct

of activities solely because activities are in specific locations (such as wetlands, floodplains, historic

places and other locations).

Chemical-, action- and location-specific ARARs and TBCs are discussed individually below.


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2.2.2 Chemical-Specific ARARs and TBCs

Chemical-specific ARARs include state and federal requirements that regulate contaminant levels in

various media. TBCs include proposed regulations and policy or guidance documents. Summaries of

potential chemical-specific ARARs for OU#2 groundwater are presented in Appendix B.

2.2.3 Action-Specific ARARs

Action-specific ARARs are regulatory requirements that define acceptable treatment and disposal

procedures. The potential actions for OU#2 groundwater are summarized in Appendix B.

2.2.4 Location-Specific ARARs

Location-specific ARARs are requirements for contaminant concentrations or remedial activities resulting

from a site’s physical location. These ARARs are summarized in Appendix B.

2.3 AREAS AND VOLUMES THAT REQUIRE REMEDIATION

This section discusses the estimated areas and volume of groundwater that would require remediation.

Estimated areas and volume are based on data collected during the RI.

2.3.1 Groundwater

The area of greatest groundwater contamination (composed of the four COCs - PCE, TCE, cis-1,2-DCE,

and VC) is located between monitoring wells MW-4I and MW-4D in the northwest (near the northeast

corner of the Copley Square Plaza site) to monitoring well MW-15D to the southeast (near the corner of

Meadow Run and Copley Road, adjacent to commercial property owned by the Copley Meadows

Condominium Association) (see Figure 2), which is a total linear distance of about 600 feet. The plume

is about 200 feet across at the widest location (measured from monitoring wells MW-3I and MW-3D to

the southwest to monitoring well MW-30S to the northeast). Lower concentrations of PCE, cis-1,2-DCE,

and VC were detected south and southeast of well MW-15D and Copley Road in wells MW-17D, MW-

20D, MW-21D, MW-22I, MW-22D, MW-23I, MW-24I, and MW-24D. However, the maximum

detected concentration of these three COCs were detected in downgradient well locations MW-22D (PCE

– 0.35 µg/L) and MW-17D (cis-1,2-DCE – 4.4 µg/L and VC – 0.73 µg/L), which is below their respective

MCLs.


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2.4 ASSUMPTIONS

The following assumptions were made regarding the development of alternatives for OU#2 groundwater:

The use designation for the intermediate and deep groundwater zones (OU#2) was determined

using the Federal Groundwater Classification System (EPA 1984) because Ohio does not have a

Comprehensive State Groundwater Protection Program in place. Under the federal classification

system, the intermediate and deep groundwater zones that make up OU#2 would be classified as a

Class IIA aquifer, because the groundwater is considered a current source of drinking water with

the presence of operating drinking-water wells located at 2631 Copley Road (Lorantffy Care

Center) and 2581 Copley Road (church property) southeast of the Copley Square Plaza site.

Based on this classification the beneficial use for OU#2 groundwater is for drinking water

purposes and should be remediated to the National Primary Drinking Water Standards (40 CFR

Part 141).


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3.0 GENERAL RESPONSE ACTIONS FOR OU#2 GROUNDWATER

GRAs include broad categories of actions to potentially be taken at a site, such as containment,

institutional actions, collection, treatment, discharge, or a combination of these actions. Technology types

and specific process options exist under each GRA. GRAs satisfy RAOs for OU#2 groundwater and

achieve applicable cleanup criteria. The cleanup criteria for OU#2 groundwater are specified in Table 2-

1. COCs in OU#2 groundwater can potentially come into direct contact with or be ingested under current

and future land-use scenarios. GRAs, remedial technologies, and process options identified for OU#2

groundwater are summarized in Appendix C and are discussed below.

3.1 GRAs, TECHNOLOGY TYPES AND PROCESS OPTIONS FOR OU#2 GROUNDWATER

According to EPA’s “Guidance for Conducting Remedial Investigations and Feasibility Studies Under

CERCLA” (EPA 1988), the categories of GRAs for groundwater include the following: no action,

institutional controls, containment, in situ treatment, collection and ex situ treatment, and discharge.

GRAs are derived based on engineering judgment and experience with response actions proven successful

for the COCs in OU#2 groundwater. Process options and remedial technologies for OU#2 groundwater

are described in Appendix C. Each GRA and the associated process options potentially applicable to the

OU#2 groundwater are discussed below.

3.1.1 No Action

The no action GRA will be carried forward in the screening evaluation as a baseline that represents

current site conditions as required by the NCP.

3.1.2 Institutional Controls

Institutional controls are legal and administrative mechanisms to implement land use and access

restrictions to limit the exposure of hypothetical landowners or users of the property to site contamination.

Institutional controls can also be used to maintain the integrity of a response action. Monitoring and

inspections are conducted to ensure the land use restrictions are being followed and are effective.

Institutional controls include restrictive covenants, access restrictions, land use restrictions and

engineering controls.


22

Typical institutional control options for groundwater include access restrictions and groundwater

monitoring. Access restrictions would prohibit the consumption of groundwater by restricting installation

of water wells. Groundwater monitoring would be used in conjunction with these restrictions to evaluate

increasing or decreasing contaminant concentrations in groundwater over time. Groundwater monitoring

could conceivably verify that no further action is necessary or trigger another GRA, and is usually

conducted in conjunction with other groundwater GRAs.

3.1.3 Containment

Containment includes an engineering control, such as physical barriers (hydraulic control or vertical

barriers), used to reduce or eliminate the pathway for potential human exposure to contaminated

groundwater. Typically, containment is used in conjunction with some form of institutional control to

ensure proper monitoring and maintenance of the engineering control.

3.1.4 Treatment

Treatment includes in situ or ex situ treatment of groundwater to reduce contaminant toxicity, mobility, or

volume through treatment. In situ groundwater treatment consists of treating groundwater in place with

biological and physical/chemical process options. Ex situ groundwater treatment requires the collection

and treatment of groundwater to reduce contaminant concentrations to acceptable levels. Groundwater

collection may involve extraction wells or subsurface drains through interceptor trenches. Treatment

options for ex situ treatment include biological and physical/chemical treatment processes.

3.1.5 Monitored Natural Attenuation

This technology involves natural subsurface processes such as dilution, volatilization, biodegradation,

adsorption, and chemical reactions with subsurface materials that are allowed to reduce contaminant

concentrations to acceptable levels. Monitoring is required to confirm that the processes are reducing

contaminant concentrations.


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4.0 PRELIMINARY SCREENING OF REMEDIAL TECHNOLOGIES AND GRAs

This section presents the preliminary screening of technologies and process option in terms of three broad

screening criteria: effectiveness, implementability, and cost (EPA 1988). The range of remedial

technologies and process options were reduced with respect to technical practicability, site conditions,

waste characteristics, and chemical properties, as well as the ability of the technology to meet the

requirements of the NCP and the RAOs.

4.1 SCREENING CRITERIA

The screening process evaluates the various technologies that fall within each of the GRAs identified in

Section 3.1 for effectiveness, implementability, and cost. The three criteria are described below.

4.1.1 Effectiveness

The evaluation of effectiveness focused on (1) the ability of the technology to address COCs in OU#2

groundwater, (2) the ability of the technology to meet the remedial goals, and (3) the reliability of the

technology. Using a remediation time frame, a technology is classified as short term (achieving the

remedial goals after less than 3 years of implementation), medium term (achieving the remedial goals

after 3 to 10 years of implementation), or long term (requiring more than 10 years of implementation to

achieve the remedial goals) (FRTR 2010).

4.1.2 Implementability

The evaluation of implementability encompasses both the technical and the administrative feasibility of

implementing a remedial technology. Technical feasibility includes compatibility with site-specific

conditions; the availability of equipment; the ease of constructing the remediation system; the labor

intensiveness required by the system; and the availability of contractors or vendors that have the

capability to design, construct, and maintain the system. Administrative feasibility includes the ease of

obtaining approvals from other offices and agencies and the requirements for, and availability of, specific

equipment and technical specialists.


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4.1.3 Cost

The evaluation of cost addresses direct and indirect capital costs and annual operation and maintenance

(O&M) costs. The relative cost for each process option is described qualitatively as low, moderate, or

high. The cost ranges are based on a review of the literature, quotations, professional or engineering

judgment, or data prepared for other studies.

4.2 EVALUATION OF GRAs AND PROCESS OPTIONS FOR OU#2 GROUNDWATER

Potentially applicable GRAs identified for OU#2 groundwater consist of the following: (1) no action, (2)

institutional controls, (3) containment, (4) treatment, and (5) monitored natural attenuation (MNA). The

initial screening of process options for the remedial technology types for these groundwater GRAs is

shown in Appendix C. This table presents the various technology types, process options and screening

analysis results for each groundwater GRA. The rationale for those options eliminated and considered for

further evaluation is discussed below and is summarized in Appendix C.

4.2.1 No Action

The NCP requires that the no action alternative be carried through the detailed analysis of alternatives.

Under the no action response, no remedial action is taken and groundwater is left as is without

implementation of any institutional controls, containment, removal, treatment, or monitoring actions. The

no action response would not be an effective alternative that satisfies the RAOs or meets the requirements

of CERCLA, because groundwater at OU#2 may pose a risk to human health (see the HHRA). No cost is

associated with this option because no action is taken. The no action option will be retained for further

evaluation as a remedial alternative for comparison, as required under the NCP.

4.2.2 Institutional Controls

Institutional controls would be used to prevent contact with COCs in OU#2 groundwater. This would

include land use restrictions to restrict construction, agricultural or residential land use at the property as

well as groundwater restrictions to ensure no one uses the water for consumption. This also includes

engineering controls, such as barriers or signs, to prohibit the spread or exposure to COCs in OU#2

groundwater. Monitoring would be performed to evaluate if COCs in groundwater are decreasing due to

other remediation actions being taken at the site. Institutional controls are retained for further

consideration since they can be used in conjunction with other process options.


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4.2.3 Containment

The groundwater hydraulic control and two subsurface barrier process options associated with

containment of OU#2 groundwater are discussed below.

Hydraulic Control

Although pumping of groundwater does not destroy or treat contaminants, it controls off-site groundwater

migration and reduces the mass of contaminants in the aquifer. This method includes installation of

extraction wells downgradient of the OU#2 groundwater source area and construction of a treatment plant

or discharge to an off-site treatment facility. Submersible pumps are commonly used to collect

groundwater from extraction wells.

Pumping generally requires installation of several extraction wells at a site and pumping these wells at

specified rates to manipulate the natural hydraulic gradient and thereby containing groundwater and the

associated contaminant plume. The wells for OU#2 would be installed along a northeast-southwest line

across the east side of the OU#2 site to capture the groundwater source area impacts. The effectiveness of

pumping would depend on the design, and the number and placement of wells and specified pumping

rates. Key hydrological parameters that determine the size and shape of the capture zone formed during

groundwater extraction include aquifer thickness, hydraulic conductivity, and existing hydraulic gradient.

When aquifer parameters vary widely across a site, capture zones can differ for similarly constructed

wells pumping at similar rates.

The groundwater pump-and-treat remedy has proven to be an ineffective technology for the restoration of

aquifers to achieve RAOs. A nationwide optimization pump-and-treat evaluation of EPA Superfund sites

with groundwater pump and treat remedies, indicated that 65 percent (13 of 20) of the evaluated sites

should consider alternate technologies to replace pump and treat or should be supplemented with more

aggressive treatment (EPA 2003). Pump-and-treat systems are not consistently effective for achieving

hydraulic control. The effectiveness of extracting groundwater from heterogeneous bedrock formations is

variable. Effectiveness of containment can be maximized with adequate testing and design

considerations, including well testing design and analysis. Wells in sandstone formations are particularly

prone to fissure plugging, sand production, and casing failure (Driscoll 1986). Proper design of the sand

filter pack and well screen are important factors. As such, the influence of pumping wells cannot be

adequately determined, and effectiveness of containment is expected to be low based on the nature of the

fractured bedrock for OU#2.


26

The equipment, methods, and materials for the installation and operation of extraction wells are easily

obtainable. The construction and operation of a treatment plant would require the installation of common

treatment components and, as such, is implementable. An extensive piping network may also be required

if effluent is discharged off site. This technology includes a treatment plant, or off-site discharge, as well

as aggressive pumping and treatment and monitoring over an extended period. Therefore, the cost of this

technology is expected to be high relative to other alternatives.

Because of the nature of the hydrogeologic conditions at the OU#2 site, the expected high cost, and past

studies showing ineffectiveness of this remedy, this process option is not retained for further

consideration.

Slurry Wall

A slurry wall consists of a vertical barrier constructed of a clay/organo-clay mixture sometimes mixed

with native soil. Slurry walls are typically constructed perpendicular to groundwater flow and must be

keyed into a lower confining layer to be effective. The slurry wall would have to be keyed into bedrock

and the vertical fracturing present at the OU#2 site provides hydraulic interconnection among the various

lithologies so a good lower confining layer does not exist. Therefore, the effectiveness of a slurry wall

would be limited and difficult to implement. Slurry walls have moderate to high capital and monitoring

costs but low O&M costs. Because of the nature of the geologic and hydrogeologic conditions at the

OU#2 site, this process option is not retained for further consideration.

Sheet Piling

Sheet piling consists of a vertical barrier constructed by driving interlocking sections of steel into the

ground to create an impervious wall. Bentonite grout is often used at the joints as sealant to increase the

effectiveness of a sheet piling wall. Sheet piling walls are typically constructed perpendicular to

groundwater flow and must be keyed into a lower confining layer to be effective. As stated above for the

slurry wall, a good lower confining layer does not exist at the OU#2 site therefore this option would not

be effective. This process option has moderate to high capital and monitoring costs but low O&M costs.

Because of the nature of the geologic conditions at the OU#2 site, this process option is not retained for

further consideration.


27

4.2.4 In Situ Groundwater Treatment

In situ groundwater treatment involves the use of physical, chemical, biological or a combination of these

treatment processes to reduce the toxicity, mobility, or volume of groundwater in place. In situ treatment

process options were evaluated, including the following five options: air sparging/biosparging (AS/B),

chemical reduction using reactive iron, surfactant enhanced chemical oxidation, bioremediation, and

thermal conduction heating. Each of these process options is discussed below.

AS/B

Air sparging is a process where air is injected directly into the saturated subsurface to volatilize

contaminants from the liquid phase to the vapor phase for treatment and/or removal in the vadose zone.

Biosparging refers to a certain type of air sparging system with the intent of stimulating biodegradation

rather than volatilization, typically by using lower air injection rates of oxygen (DoD 2011). For AS/B, a

series of injection wells would inject air into groundwater, where dissolved and adsorbed contaminants

would be removed by air stripping. This process option would typically be used in conjunction with soil

vapor extraction (SVE). SVE wells would collect vapor-phase contaminants from groundwater as they

migrate upward into vadose or unsaturated zone soil.

The effectiveness of air sparging depends largely on site-specific physical characteristics. Air sparging is

generally more effective in homogeneous, coarse-grained (high permeability) soil. Low permeability

formations, such as bedrock and highly heterogeneous soil, can lead to slow mass transfer rates reducing

its effectiveness (DoD 2011). The effectiveness of air sparging can be increased by injecting large

volumes of air into groundwater. Higher air injection pressures, required to treat groundwater underlying

fine-grained soil, can cause the formation of significant subsurface gas pockets from bubble coalescence.

High air injection pressures can also fracture air sparging well annular seals or weaken joints in the soil,

resulting in a loss of system efficiency.

Air sparging equipment is fairly simple and consists of injection wells, an oil-free air compressor, a

vacuum blower, an air and water separator, piping, and valves and instrumentation. Startup and shutdown

can be accomplished fairly quickly. However, the slow mass transfer rates expected for the OU#2

fractured bedrock formation can lead to an extended period of operation and limited vapor recovery. This

process option has moderate capital, O&M and monitoring costs. O&M and monitoring costs could

increase if an extended period of operation is required.


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This process option has been retained for further consideration since it may be effective if used in

conjunction with an enhanced bioremediation system that is discussed further below.

Chemical Reduction

Injection of zero-valent iron (ZVI) has been proven highly effective at treating chlorinated compounds

and was selected as part of the alternative for OU#1. Nanoscale iron particles provide destruction of a

wide range of chemicals based on an oxidation-reduction process where the chemical serves as an

electron acceptor and ZVI as the electron donor. Chlorinated compounds, such as TCE can accept

electrons from ZVI and be reduced to nontoxic end products including ethene and ethane. ZVI particles

have been shown to be effective for a variety of compounds because of the surface area, subsurface

distribution potential, and contact times in low permeability zones (DoD 2011). The particles typically

range in size from 1-100 nanometers (nm) in diameter and are injected as a slurry with water. The 1-100

nm size particles should reach smaller aperture fractures in bedrock.

Treatment by ZVI has been shown to be immediately effective and sustained for an extended period.

Following treatment by ZVI, the groundwater will be in a reduced state, as dissolved oxygen will be

eliminated, ORP will be lowered, and pH will decrease. The reducing conditions created by ZVI

treatment are also favorable for stimulating the growth of anaerobic bacteria capable of degrading

compounds not treated directly by ZVI. If needed, this natural microbial degradation can be enhanced

through the addition of nutrients and an electron acceptor or energy source (such as sulfate, lactate,

emulsified oil, chitin or whey powder) referred to as enhanced biodegradation.

This technology is expected to have a high degree of effectiveness and past studies have shown the

capability of ZVI in treating chlorinated compounds in bedrock aquifers (EPA 2014). ZVI and

accelerated biological treatment (if needed) are also expected to enhance the natural attenuation of COC

impacts in the downgradient portion of the OU#2 groundwater plume. Because ZVI may be highly

effective, and enhanced biodegradation has the potential to be a complementary and long-term treatment

measure, this process option has been retained for further consideration.


29

Surfactant Enhanced Chemical Oxidation

Chemical oxidation uses chemicals (referred to as oxidants) to help change harmful compounds into less

toxic ones. Chemical oxidants (such as, hydrogen peroxide, Fenton’s reagent, ozone and permanganate)

would be injected into the subsurface through injection wells to destroy compounds by converting them to

innocuous compounds commonly found in nature. A commonly used chemical oxidant is Fenton’s

Reagent, which involves the application of hydrogen peroxide with an iron catalyst. When this

application is done, a hydroxyl radical is formed, which is a strong oxidizing agent and is capable of

oxidizing many complex organic compounds. Any residual hydrogen peroxide decomposes to water and

oxygen and remaining iron particles ultimately settle out in the subsurface. In order to use hydrogen

peroxide, it may be necessary to use stabilizers because of the compound’s volatility (EPA 2014).

Injection wells are typically installed at different depths in the source area to reach as much dissolved and

undissolved contamination as possible. Once the oxidant is pumped down the wells, it spreads into the

surrounding soil and groundwater where it mixes and reacts with contaminants. To improve mixing, the

groundwater and oxidants may be recirculated between wells which involves pumping oxidants down one

well and then pumping the groundwater mixed with oxidants out another well. After the mixture is

pumped out, more oxidant is added, and it is pumped back (recirculated) down the first well.

Recirculation helps treat a larger area faster. Another option is to inject and mix oxidants using

mechanical augers or excavation equipment. Delivery of chemical oxidants through injection is effective

in subsurface media with moderate to high hydraulic conductivity values and may be limited in bedrock.

Surfactants can also be added with chemical oxidants through co-injection or sequential injections of

surfactants and oxidants. Surfactants facilitate contaminant removal by enhancing the mobility of the

contaminant by reducing interfacial tension and increasing the contaminant solubility which creates

micro-emulsions. The emulsions increase the interface area between the contaminant and the oxidant,

which increases the efficiency of the chemical oxidant treatment (DoD 2008).

This technology has the ability to treat a wide variety of organic compounds. However, the effectiveness

is limited due to potential clogging concerns which could limit the delivery of the oxidants, and the

altered geochemistry which could adversely impact the beneficial natural attenuation processes present.

This process option is not retained for further consideration because of the expected high costs of multiple

treatments and well maintenance/replacement due to formation fouling; the negative impacts to the


30

existing natural attenuation processes; and clogging issues that could limit delivery of oxidants to deeper

portions of the OU#2 bedrock aquifer.

Enhanced Bioremediation

Enhanced bioremediation involves the injection of suitable substrate into the subsurface to stimulate the

existing microbial population through enhanced reductive dechlorination (anaerobic) or air/oxygen

sparging (aerobic). Microbial presence usually decreases through the vadose zone as nutrients decrease,

and then increases with the presence of water in the saturated zone. Microorganisms were once believed

to be nonexistent in bedrock fractures but laboratory-and field-scale studies indicate that microbial

activity is feasible. When contamination is introduced to a subsurface environment and conditions

permit, the native microbes may be able to metabolize the contaminants into water or carbon dioxide. In

some cases, the contamination can destroy or inhibit the microbes if the concentration is above the

microbes threshold; however, microbes tend to have the ability to adapt to their environment utilizing the

predominant compounds for energy. Microbes have the ability to use oxygen or carbon dioxide or

chlorinated compounds as an electron acceptor depending on the availability of each. Microbes under

conditions with no oxygen can use chlorinated compounds as a source of energy with dissolved hydrogen

as the electron acceptor. Other microbes can co-metabolize compounds when more than one substrate or

carbon source is available. This process involves the production of an enzyme by the microbe during the

metabolic process. The enzyme then breaks down the substrate or contaminant (EPA 2002).

An enhanced bioremediation system can be implemented alone if reducing conditions are present or in

conjunction with an AS/B or chemical reduction system. This alternative could be implemented utilizing

the same injection well network as chemical reduction or AS/B and could be used as a complementary

treatment following chemical reduction, in that the reducing conditions enhanced by ZVI are optimal for

the continued degradation of chlorinated compounds. To increase degradation, nutrients and/or

microorganisms can be injected as a substrate to produce optimum conditions for achieving

dechlorination.

Enhanced bioremediation is expected to have a moderate degree of effectiveness. The enhanced

biological treatment is also expected to enhance the natural attenuation of COC impacts in the

downgradient portions of the OU#2 plume area.


31

This technology is expected to have moderate to high costs due to multiple injections of substrates that

may be required to achieve cleanup levels, and gene probe techniques required to verify survival of

microorganisms.

Because enhanced bioremediation has the potential to be highly effective as a long-term treatment

measure, this process option has been retained for further consideration.

Thermal Conduction Heating

Thermal treatment systems have been applied to various chlorinated compound sites, using steam

injection, electrical resistance heating, and conductive heating. Each approach has advantages and

limitations. The most widely used approach is thermal conduction heating (TCH), which involves

placing electrical resistance heating elements through a target zone (EPA 2014). An electrical current is

passed through the resisters to generate heat that subsequently moves through the targeted groundwater

through conduction. Contaminants are either destroyed in situ through pyrolysis or recovered through

vapor or liquid recovery systems. The target can be in the vadose zone, in the groundwater zone, or a

combination of both. It is sometimes more difficult to treat the groundwater zone due to higher water

content and the potential for inflow of cool groundwater during treatment (DoD 2011).

TCH can perform extremely well for chlorinated compounds in unsaturated soils, and is also likely to be

very effective in treating DNAPL and compounds in low permeability zones, including bedrock (DoD

2011). Full-scale studies of TCH heating of fractured bedrock has shown that thermal treatment is

capable of achieving thorough heating of bedrock (matrix and fractures) and capture and removal of

contaminant mass from bedrock and unconsolidated deposits (EPA 2014).

This technology could be highly effective in treating the COCs in the fractured bedrock at OU#2;

however, the potential for further biodegradation may be reduced as high temperatures may inhibit

growth of or kill microorganisms due to high heat. This technology also requires a significant number of

vertical holes be placed throughout the target area to ensure complete heating. Incomplete heating, inflow

of low temperature groundwater, and missed portions of the source zone can lead to significant

contaminant mass remaining in the source zone. Due to the expected high cost of installation and energy

use for this process option, it is not retained for further consideration.


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4.2.5 Monitored Natural Attenuation

As mentioned in Section 1.2.3, the site characteristics will be further assessed to determine if they

naturally promote aerobic or anaerobic biodegradation. This process option would include MNA for

COC impacts in groundwater in the OU#2 plume. There is some evidence to suggest that natural

attenuation could be occurring. A general discussion of natural attenuation geochemical data collected

during the RI, and evaluation of existing conditions is provided in Section 1.2.3. This technology would

include the existing network of wells for monitoring of the OU#2 source area and downgradient plume

area over an extended period of time. The details of the monitoring program would be developed in

cooperation with EPA and Ohio EPA during design.

The COCs, field parameters, and geochemical parameters including dissolved oxygen, ORP, turbidity,

pH, temperature, specific conductance, methane, ethane, ethene, total organic carbon, alkalinity, nitrogen,

nitrate, nitrite, sulfate, sulfide, manganese, ferrous iron, and chloride would continue to be monitored to

evaluate the effectiveness of MNA. Water levels would also continue to be collected during each

sampling event to monitor groundwater flow and direction.

Data is not available currently to support a favorable effectiveness rating for this process option as a sole

remedy; however, when combined with another in situ treatment process (see Section 4.2.4) in the source

area of OU#2, MNA is expected to have a moderate to high effectiveness rating.

MNA is easy to implement because it relies on natural biochemical and physical processes that already

exist and that do not require enhancement. Low to moderate capital, maintenance, and monitoring costs

are associated with MNA; therefore, the costs for implementing MNA are lower compared to other

process options. Because MNA can be used by itself or in conjunction with other treatment technologies

it is retained for detailed analysis.


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4.3 SUMMARY OF RETAINED PROCESS OPTIONS

The various groundwater process options that have been retained for development of remedial alternatives

are presented in the table below.

Retained Groundwater Process Options

No Action

Institutional Controls

In Situ Air Sparging/Biosparging

In Situ Chemical Reduction

In Situ Enhanced Bioremediation

Monitored Natural Attenuation


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5.0 DEVELOPMENT OF REMEDIAL ALTERNATIVES

This section describes the development of remedial alternatives for OU#2 groundwater at the Copley

Square Plaza site. The alternatives include only remedial process options that merited further evaluation

after the initial screening discussed in Section 4.0. Each alternative was developed to address the RAOs

identified and to achieve the overall goal of protecting human health and the environment.

According to Section 4.1.2.1 of EPA’s “Guidance for Conducting Remedial Investigations and Feasibility

Studies under CERCLA,” (EPA 1988) the screening effort may be minimized or eliminated if the number

of viable or appropriate alternatives for addressing site problems is limited. The scope of the screening

effort can vary substantially, depending on the number and type of alternatives developed and the extent

of information necessary for conducting the detailed analysis.

This section also provides screening information for the alternatives developed. The purpose of the

alternative screening evaluation is to potentially reduce the number of alternatives that will undergo a

more thorough and extensive analysis. Based on EPA guidance (EPA 1988) and as presented in Section

4.1, the criteria used during alternative screening includes effectiveness, implementability, and cost.

Considerations of sustainability potentially reduces collateral impacts of the remediation process and

seeks to identify approaches to the site remediation that can also address community needs. Evaluation of

collateral impacts (particulate and greenhouse gas emissions, water consumption, waste generation, truck

traffic, and noise) related to each screened remediation alternative will be conducted. Results will be

reported in the FS report. A preliminary assessment of sustainability to screen the various remedial

alternatives for treating groundwater COCs has been evaluated based on the following criteria:

Reduces air pollutant emissions and greenhouse gas production

Minimizes impacts to water quality and water resources

Minimizes material use and waste production

Conserves natural resources and energy

Although sustainability is not one of the NCP criteria, SulTRAC is including it in accordance with the

EPA Region 5 Greener Cleanup Interim Policy (EPA 2009). A more detailed evaluation of the

sustainability of each alternative will be included in the FS report.


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5.1 DESCRIPTIONS OF ALTERNATIVES FOR OU#2 GROUNDWATER

Each of the groundwater alternatives is described below and was assembled to accommodate different

scenarios and to allow EPA flexibility. Uncertainties and limitations pertaining to groundwater

alternatives are also discussed.

The following alternatives are considered for OU#2 groundwater: (1) no action; (2) institutional controls

and MNA; and (3) in situ treatment.

5.1.1 Groundwater Alternative 1 – No Action

The no action alternative provides a baseline for comparison to other alternatives. Under Groundwater

Alternative 1, no action would be taken to remediate groundwater at the OU#2 site under a remedial

action. Under the no action alternative, no groundwater would be treated.

Effectiveness

The no action alternative would not reduce the toxicity, mobility, or volume of contaminated groundwater

at the OU#2 site, and therefore would not be protective of human health or the environment.

Implementability

Although this alternative would be easily implemented, the administrative feasibility of selecting this

alternative is very low. It is unlikely that EPA or Ohio EPA would approve of this alternative because it

would not provide a mechanism for ensuring adequate protection of human health and the environment.

Cost

No capital or O&M costs are associated with this alternative.

Sustainability

Sustainability is not a means of justifying a no action remedy or less remediation than necessary to

achieve the RAOs.


36

The tick (√) and check (×) marks against the sustainability criteria indicate affirmation or negative impact

with respect to the treatment alternative. NA indicates not applicable.

Ability to reduce air pollutant emissions and greenhouse gas production (NA)

Minimizes impacts to water quality and water resources (NA)

Minimizes material use and waste production (NA)

Conserves natural resources and energy (√)

Decision

The no action alternative will be retained for detailed analysis because the NCP requires that it be used as

a standard for evaluating the performance of other remedial alternatives.

5.1.2 Groundwater Alternative 2 – Institutional Controls and MNA

This alternative would require institutional controls to restrict the use of OU#2 groundwater at the site or

for drinking water, and would institute a monitoring program to evaluate the natural attenuation of the

groundwater contamination. If determined to be a viable alternative during the FS, this alternative would

allow for continued monitoring of OU#2 groundwater. The monitoring would continue to be evaluated to

determine if concentrations were decreasing in the source area and downgradient portions of the OU#2

plume as a result of the OU#1 chemical reduction treatment in the shallow groundwater zone and existing

natural attenuation processes or if additional remedial action would be required. The existing monitoring

well network would be used to the monitor groundwater COC concentrations and the geochemical

conditions to confirm that the OU#2 plume is maintaining a reducing environment for microbial processes

to occur.

Effectiveness

This alternative would be effective in restricting access and use of the groundwater and therefore

preventing direct contact with or ingestion of COCs in OU#2 groundwater; however, there is insufficient

data currently available to support a favorable effectiveness rating for MNA as a sole remedy. MNA

combined with an in situ treatment alternative is expected to be moderately to highly effective.


37

Implementability

This alternative is easy to implement, since it relies on natural biochemical and physical processes. The

services and materials required to implement this alternative are standard within the industry and readily

available. It would require the use of institutional controls to restrict access to and use of the

groundwater.

Cost

Depending on the frequency and number of wells requiring monitoring, the cost of MNA is expected to

be low to moderate. Costs include regular sampling of wells, laboratory chemical analyses, data

evaluation, and well maintenance costs.

Sustainability

Ability to reduce air pollutant emissions and greenhouse gas production (√)

Minimizes impacts to water quality and water resources (√)

Minimizes material use and waste production (√)


Decision

Because of the high potential for effectiveness and easy implementability, this alternative has been

retained for further consideration.

5.1.3 Groundwater Alternative 3 – In Situ Treatment

The following in situ treatment alternatives are considered for OU#2 groundwater: (1) air

sparging/biosparging, (2) chemical reduction, and (3) enhanced bioremediation. Treatability studies

would be completed for the in situ alternatives to determine the radius of influence, injection spacing,

injection rates, and efficacy of the reagents, substrates, microorganisms, or oxygen used in treating the

chlorinated compounds in OU#2 groundwater. Tracer testing may also be considered during treatability

testing to evaluate flow patterns and velocity through the OU#2 fractured bedrock aquifer.


38

5.1.3.1 AS/B

This alternative is comprised of an air sparging system operated in conjunction with an SVE system.

Both the air sparging and SVE wells would be strategically located in the area of highest contamination,

which is the source area for OU#2. The air sparging system forces air through the saturated zone where it

volatilizes contaminants in groundwater into the unsaturated zone. These vapors are collected through the

SVE system and routed to a system for treatment. Biosparging wells would move air horizontally and

vertically through the saturated and unsaturated zones to provide sufficient oxygen for the native

microbial population to promote biodegradation in the source area. A full description of the AS/B

technology is presented in Section 4.2.4.

Effectiveness

This alternative would not be effective in treating OU#2 groundwater because of the low permeability and

depth of the fractured bedrock aquifer. This would result in slow mass transfer rates from the bedrock

aquifer to the overlying unsaturated zone, which would reduce vapor recovery. However, if this

alternative was used in conjunction with an enhanced bioremediation technology, it could be moderately

effective for biodegradation of OU#2 groundwater. Pneumatic fracturing techniques may increase the

effectiveness of this alternative in getting oxygen to the deeper portions of the bedrock aquifer for OU#2.

Implementability

Installation of air sparging and SVE wells utilizes proven technology and is easily implementable.

Treatment of collected condensate and vapors uses proven technologies and could be easily implemented

at the site. The development of a monitoring plan to track contaminant levels is also easily implemented.

Cost

This alternative would have moderate capital costs and moderate to high O&M and monitoring costs,

dependent on the duration of operation.

Sustainability

Reduces air pollutant emissions and greenhouse gas production (×)





39

Decision

This alternative would be easy to implement and could be moderately effective if used with an enhanced

bioremediation alternative so it is retained for further consideration.

5.1.3.2 Chemical Reduction

Injection of ZVI is an alternative that has been shown to be highly effective in treating chlorinated

compounds through reduction pathways. ZVII is currently being used to treat the same COCs in OU#1

shallow groundwater zone at the Copley Square Plaza site. A full description of this technology is

presented in Section 4.2.4.

The ZVI slurry would be injected through wells strategically placed in the source area for OU#2.

Groundwater treatment by ZVI would result in reduction of the already low ORP observed at some well

locations to a highly reduced state. This geochemical condition will further stimulate the growth of

anaerobic bacteria capable of degrading COCs potentially not treated by the iron particles. As discussed

in Section 1.2.3, natural biodegradation processes may already be occurring slowly and the use of ZVI

will stimulate these existing processes. This microbial degradation can be accelerated (if necessary) by

addition of nutrients and an energy source. Treatability studies would be conducted to define design and

operational variables to determine ZVI slurry injection volumes and frequency. After the initial injection

period, consideration will be given to continuing with the ZVI injections and/or implementing enhanced

biological treatment injections, which may be a more effective long-term treatment measure. An

enhanced bioremediation system can be implemented utilizing the same injection well network and is a

complementary treatment following ZVI, in that the reducing conditions enhanced by ZVI could optimize

the continued degradation of the OU#2 COCs in groundwater. Both ZVI and enhanced biological

treatment are expected to enhance the natural attenuation of COC impacts in the downgradient portion of

the OU#2 groundwater plume.

Effectiveness

This technology is expected to have a high degree of effectiveness. Experience has shown the capability

of ZVI in effectively treating a large number of chlorinated compounds and has shown positive results to

date following application to OU#1 groundwater at the site.


40

Implementability

The implementability of this technology is considered to be moderately easy when compared to other

methods. Fracturing could provide more effective emplacement of ZVI in deeper portions of the OU#2

bedrock aquifer (Moreno et al. 2010).

Cost

The cost of this technology is expected to be moderate. Fracturing, if required, would increase the cost of

this alternative.

Sustainability

Reduces air pollutant emissions and greenhouse gas production (√)




Decision

Because ZVI has the potential to be highly and immediately effective, this alternative has been retained

for further consideration.

5.1.3.3 Enhanced Bioremediation

This alternative has been shown to be highly effective in complete dechlorination of the COCs found in

OU#2 groundwater by injecting suitable substrates (electron donors and nutrients) and/or supplying

microorganisms that have demonstrated the ability to completely dechlorinate the chlorinated compounds.

Enhanced bioremediation can also be complemented with an AS/B or chemical reduction system to

accelerate biological treatment. A full description of this technology is presented in Section 4.2.4.

Microcosm studies would need to be performed to identify appropriate substrates required and to

determine whether complete degradation of the COCs could be achieved through enhanced

bioremediation. The substrates would be injected through wells strategically placed in the source area for

OU#2. The system would be monitored using the existing monitoring well network to ensure

optimization of the biological system. If microorganisms are added, gene probe techniques may also be

required to verify initial and continued survival and propagation of the microorganisms.


41

Effectiveness

This alternative is expected to be moderately effective. Using this alternative in conjunction with an

AS/B or chemical reduction technology would increase the effectiveness of this method.

Implementability

The implementability of this technology is considered to be moderate. This alternative may require

fracturing for emplacement of substrates in deeper portions of the OU#2 bedrock aquifer.

Cost

The cost of this technology is expected to be moderate. Fracturing and/or gene probe techniques would

increase the cost of this alternative.

Sustainability

Reduces air pollutant emissions and greenhouse gas production (√)




Decision

Because this alternative has the potential to be highly effective especially when used with AS/B or

chemical reduction technologies, it has been retained for further consideration.

Below is a summary of the alternatives retained for consideration by EPA and Ohio EPA for the purposes

of preparing the FS report.

Media Alternative

Number

Alternative Title

Groundwater 1 No Action

2 Institutional Controls and Monitored Natural

Attenuation

3 In Situ Treatment – Air Sparging/Biosparging,

Chemical Reduction, and Enhanced Bioremediation


42

5.2 COMPARISON OF ALTERNATIVES TO NCP CRITERIA

The matrix below presents a rating of the remedial alternatives with respect to the following NCP

threshold criteria:

Overall Protection of Human Health and the Environment

Compliance with ARARs

and NCP balancing criteria:

Long-Term Effectiveness and Permanence

Reduction of Toxicity, Mobility, or Volume through Treatment

Short-Term Effectiveness

Implementability

Cost

The purpose of rating the criteria is to present basic advantages and disadvantages of each alternative

thereby providing a basis for remedy selection consistent with the NCP. A more detailed analysis of

NCP criteria will be presented in the FS report. Both qualitative and quantitative evaluations of the

screened alternatives are also shown in the matrix. The scorings are preliminary and based on a scale

of 0 to 10, with 10 being the strongest and 0 being the weakest. The overall rankings in the last

column provides the average score of the specific alternative based on the five NCP balancing

criteria.


43


44

6.0 REFERENCES

Department of Defense (DoD). 2005. “Bioaugmentation for Remediation of Chlorinated Solvents.”

Environmental Security Technology Certification Program (ESTCP). October.

DoD. 2008. “Development of Assessment Tools for Evaluation of the Benefits of DNAPL Source Zone

Treatment.” Strategic Environmental Research and Development Program (SERDP)

SERDP Project No. ER-1293. September.

DoD. 2011. “A Guide for Selecting Remedies for Subsurface Releases of Chlorinated Solvents.”

ESTCP Project No. ER-200530. March.

Federal Remediation Technologies Roundtable (FRTR). 2010. “FRTR Remediation Technologies

Screening Matrix and Reference Guide, Version 4.0.” Accessed November 4, 2014. On-line

Address: <http://www.frtr.gov>.

Moreno, J., Swift, D., Rothermel, J., Starr, R., Bures, G., Shetty, N., Zenker, M., McKeon, J., and D.

Knight. 2010. “Fracture Emplacement of a Micro-Iron/Carbon Amendment for TCE Reduction

in a Bedrock Aquifer.” 7th International Battelle Conference on Remediation of Chlorinated and

Recalcitrant Compounds. May.

SulTRAC. 2014. Remedial Investigation Report, Copley Square Plaza Operable Unit 2 Site, Copley

Township, Ohio. Prepared for EPA under Contract No. EP-S5-06-02. August 22.

U.S. Environmental Protection Agency (EPA). 1984. Guidelines for Ground-Water Classification Under

the EPA Ground-Water Protection Strategy. Final Draft. November 1986.

Driscoll, F. 1986. Groundwater and Wells, Second Edition. December.

EPA. 1988. Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA.

Interim Final. EPA/540/G-89/004. October.

EPA. 1998. “Evaluation of Subsurface Engineered Barriers at Waste Sites.” EPA 542-R-98-005. August.

EPA. 2000. The Office of Solid Waste and Emergency Response (OSWER) publication on Land Use

Controls. Online at: <http://www.epa.gov/oerrpage/superfund/action/ic/guide/index.htm>.

EPA, 2002. “Bioremediation of Chlorinated Solvents in Fractured Bedrock: Characterization and Case

Studies.” Prepared by National Network of Environmental Management Studies Fellow for

EPA OSWER. August.

EPA. 2003. “Improving Nationwide Effectiveness of Pump-and-Treat Remedies Requires Sustained and

Focused Action to Realize Benefits.” Report No. 2003-P-000006. March 27.

EPA. 2004. “Demonstration of Two Long-Term Groundwater Monitoring Optimization Approaches.”

OSWER 5102G. EPA 542-R-04-001b. September.

EPA. 2009. Region 5 Greener Cleanup Interim Policy. November 12.

http://www.esaa-events.com/remtech/2009/pdf/09-Bures.pdf

http://www.esaa-events.com/remtech/2009/pdf/09-Bures.pdf

http://www.epa.gov/oerrpage/superfund/action/ic/guide/index.htm


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EPA. 2014. CLU-IN – Fractured Rock Remediation, Technology Innovation and Field Services

Division. October. Accessed October 21, 2014. On-Line Address: http://www.clu-

in.org/contaminantfocus/default.focus/sec/Fractured_Rock/cat/Remediation/

Weston. 2008. Final Remedial Investigation Report, Revision 4, Copley Square Plaza Site, Copley

Township, Summit County, Ohio. July 28.

Weston. 2009. Draft Final Feasibility Study Report for Operable Unit #1 of the Copley Square Plaza

Site Copley, Summit County, Ohio. June 12.

http://www.clu-in.org/contaminantfocus/default.focus/sec/Fractured_Rock/cat/Remediation/

http://www.clu-in.org/contaminantfocus/default.focus/sec/Fractured_Rock/cat/Remediation/


FIGURES


APPENDIX A

DISTRIBUTION OF CONTAMINANTS OF CONCERN CONCENTRATIONS


APPENDIX B

APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS


APPENDIX C

PRELIMINARY SCREENING OF GENERAL RESPONSE ACTIONS,

TECHNOLOGY TYPES, AND PROCESS OPTIONS

Documents

SULTRAC - REMEDIAL ALTERNATIVES … Assignment No. : ... TCH Thermal conduction heating ... Remedial Alternatives Screening Technical Memorandum Copley Square Plaza Site