Naval Industrial Reserve Ordnance Plant (NIROP) Fridley ... · EPIII'.' 291216 . Third Five-Year Review Report. Naval Industrial Reserve Ordnance Plant (NIROP) Fridley, Minnesota

EPIII'.' 291216

Third Five-Year Review Report

Naval Industrial Reserve Ordnance Plant (NIROP)

Fridley, Minnesota

=Midwest

Naval Facilities Engineering Command Midwest Contract Number N62467-04-0-0055

Contract Task Order 502

October 2008

THIRD FIVE YEAR REVIEW REPORT

NAVAL INDUSTRIAL RESERVE ORDNANCE PLANT (NIROP) FRIDLEY, MINNESOTA

COMPREHENSWELONG~ERM

ENVIRONMENTAL ACTION NAVY (CLEAN) CONTRACT

Submitted to: Naval Facilities Engineering Command Midwest

201 Decatur Avenue, Building 1A Great Lakes, Illinois 60088

Submitted by: Tetra Tech NUS, Inc.

234 Mall Boulevard, Suite 260 King of Prussia, Pennsylvania 19406

CONTRACT NUMBER N62467-o4-D-0055 CONTRACT TASK ORDER 0502

OCTOBER 2008

BUSINESS LINE COORDINATOR (BlC) I REGIONAL ENVIRONMENTAL DIRECTOR

DATE

NIROP Fridley Five-Year Review

Revisior: 1 Date: October 2008

Section: Table of Contents Page 1


Revision: 1 Date: October 2008

Section: Table of Contents Page 2 of4

'--II~

TABLE OF CONTENTS (Continued)

PAGE NO.

8.0 ISSUES 8-1. 8.1 OU1 ISSUES 8-1 8.2 OU2 AND OU3 ISSUES 8-2

9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS 9-1

10.0 PROTECTIVENESS STATEMENT.........................................................................................10-1 10.1 OU1 PROTECTIVENESS STATEMENT 10-1 10.2 OU~ PROTECTIVENESS STATEMENT 10-1 10.3 OU3 PROTECTIVENESS STATEMENT 10-1

11.0 NEXT REViEW 11-1

REFERENCES R-1

ATTACHMENTS

1 TCE ISOCONCENTRATION MAPS AND APPROXIMATE CAPTURE ZONE CONFIGURATIONS

2 TREATMENT PLANT REPORT 3 MONTHLY PUMPING WELL CAPACITY ANALYSIS

TABLES

4-1 Groundwater Chemicals and Target Cleanup Levels 4-2 Current Groundwater Treatment System Chemicals of Concern 4-3 Detected Concentrations of VOCs in Compliance Wells 4-4 Site-Specific Allowable Air Emission Rates and Groundwater Concentrations 6-1 Summary of Significant Periods of Interrupted Pumping Operations

FIGURES

NUMBER

3-1 Site Location Map 3-2 Site Plan 4-1 Groundwater Extraction and Treatment System

030810/P eTa 502

http:STATEMENT.............................................................................

."..

ACL

ACP

AER

AMR

ARAR

CAH

CERCLA

CERCLIS

CFR

COC

DCA

DCE

DaO

EPA

FFA

FS

GAC

gpm

GWTF

HRL

lAS

IR

ISCST3

LUC

MCES

MDH

MK

MPCA

MWW

NCP

NIROP

NPDES

NPL

030810/P

NIROP Friclley Five-Year Revew


Section: Table of Contents Page 3 of 4

ACRONYMS

alternative concentration limit

Anoka County Park

air emission rate

Annual Monitoring Report

Applicable or relevant and appropriate requirements

Chlorinated aliphatic hydrocarbons

Comprehensive Environmental Response, Compensation, and Liability Act

Comprehensive Environmental Response, Compensation, and Liability Information

System

Code of Federal Regulations

chemical of concern

dichloroethane

dichloroethene

data quality objective

United States Environmental Protection Agency

Federal Facility Agreement

Feasibility Study

granular activated carbon

gallons per minute

groundwater treatment facility

Health risk limits

Initial Assessment Study

Installation Restoration

Industrial Source Complex Short-Term, Version 3

Land use controls

Metropolitan Council Environmental Services

Minnesota Department of Health

Morrison-Knudsen

Minnesota Pollution Control Agency

Minneapolis Water Works

National Oil and Hazardous Substances Pollution Contingency Plan

Naval Industrial Reserve Ordnance Plant

National Pollutant Discharge Elimination System

National Priorities List

eTO 502

O&M

OU

PCE

PCJ

PFBA

PFC

PFOA

PFOS

PID

POTW

RAB

RAWP

RCRA

RI

RMT

ROD

SDS

SDWA

SU

SWMU

TBC

TCA

TCE

TRC

TtNUS

UDLP

USACE

USGS

VOC

WWTP

Operation and Maintenance

Operable Unit

tetrachloroethene

Prairie du Chiene I Jordan

perfluorobutanoic acid

perfluorochemicals

perfluorooctanic acid

perfluorooctane sulfate

photoionization detector

Publicly Owned Treatment Works

Restoration Advisory Board

Remedial Action Work Plan

Resource Conservation and Recovery Act

Remedial Investigation

RMT,lnc.

Record of Decision

State Disposal System

Safe Drinking Water Act

Standard Unit

Solid Waste Management Unit

To-be considered

trichloroethane

trichloroethene

Technical Review Committee

Tetra Tech NUS, Inc.

United Defense Limited Partnership

United States Army Corps of Engineers

United States Geological Society

Volatile Organic Compound

Wastewater Treatment Plan



Section: Table of Contents Page 4 of4

""-,,

_. 030810/P CTO 502

--.., mxmo c -t

I

NIROP Fridley Five Year Review

Revision: 0 Date: August 2008

Section: Executive Summary Page 1 of 2

EXECUTIVE SUMMARY

Three operable units (OUs) have been identified at NJROP Fridley. Groundwater is identified as

Operable Unit 1. The land outside of the main NIROP manufacturing building but within the le9al

boundaries of the facility, from ground surface down to groundwater elevation, has been identified as

OU2. The land underneath the main NIROP building, and soils at elevations below groundwater

elevation (the saturated zone) either under the building or outside the building, but within the le9al

boundaries of the facility has been designated as OU3. The Record of Decision (ROD) for OU1 was

signed in September 1990, and the first Five Year Review for OU1 was signed in September 1998. Tile

ROD for OU2 and OU3 is combined in a single document, and was signed in September, 2003. Tile

selected remedy for both OU2 and OU3 is Land Use Controls. Additional chronology details are provided

in Section 2 of this Five Year Review.

The groundwater remedy for Naval Industrial Reserve Ordnance Plant (NfROP) Fridley in Fridley,

Minnesota included installation and operation of ground water and recovery wells, with a two-phased plan

for disposal of the ground water from the system. The site achieved construction completion in August

1991. The trigger for this Third Five Year Review was the last signature date of the Second Five Year

1111".. ' Review on October 31, 2003.

The assessment of this Five Year Review found that the remedy was constructed in accordance with the

requirements of the OU 1 Record of Decision. The remedy at OU1 currently protects human health and

the environment because there are no known completed pathways to receptors. However, for the

remedy to be protective in the long-term, hydraulic containment must be maintained and optimal

performance of the extraction system must be achieved to ensure long-term protectiveness.

The previous Five Year Review identified that contaminated ground water conditions in Anoka County

Park were not dissipating as anticipated in the ROD which may allow for the continual migration of these

contaminants into the Mississippi River. To address this concern, the Navy completed a pilot study U"at

involved localized injection of vegetable oil into the ground water within the Anoka County Park in an

attempt to enhance the effectiveness of the OU 1 remedy. This study is complete, and Navy does not

believe that the technology is suitable for wide-scale implementation at this site. In addition, tile

effectiveness of the ground water capture system will continually be evaluated and upgraded as

necessary.

030810/P ES-1 eTO ~;02


Revision: a Date: August 2008

Section: Executive Summary Page 2 of 2

The ROD for OU2 and OU3, specifying Land Use Controls, was signed in September, 2003. This third

five year review evaluation of protectiveness of the OU2 and OU3 remedy indicates that the Land Use

Control remedies for these OUs are functioning as intended and remain protective.

030810/P ES-2 eTO 502

Five-Year Review Summary Form

SITE IDENTIFICATION

Site Name (from WasteLAN): Naval Industrial Reserve Ordnance Plant, Fridley

EPA 10 (from WasteLAN): MN3170022914

NPL status: [2] Final D Deleted D Other (specify)

Remediation status (choose all that apply): D Under Construction [2] Operating [2] Complete

Multiple OUs?* [2] YES D NO Construction completion date: 9/23/03

Has site been put into reuse? DYES [2] NO

REVIEW STATUS

Lead agency: D EPA D State DTribe [2] Other Federal Agency DODINavy

Author name: Naval Facilities Engineering Command Midwest

Author title: IAuthor affiliation: Lead Agency Review period:** 08/01/2008 to 10/31/2008

Date(s) of site inspection: 03/13/2008 and 05/05/2008

Type of review:

[2] Post-SARA D Pre-SARA D NPL-Removal only o Non-NPL Remedial Action Site o NPL-StatelTribe-lead o Regional Discretion Review number: o 1 (first) D 2 (second) [2] 3 (third) D Other (specify) Triggering action: o Actual RA Onsite Construction at OU # - o Actual RA Start at au # __ D Construction Completion [2] Previous Five-Year Review Report D Other (specify)

--Triggering action date (from WasteLAN): 10/31/2003

--Due Date (five years after triggering action date): 10/31/2008

*["OU" refers to operable unit.] **[Review period should correspond to the actual start and end states of the Five-Year Review in WasteLAN.]

F-1

Five-Year Review Summary Form, cont'd.

Issues:

See Section 8.0 of the document for discussion about:

Repeated occurrences of electrical device failure Routinely treating groundwater extraction wells to address biological iron fouling USGS capture analysis Vegetable oil pilot study

Recommendations and Follow-up Actions:

A summary table of follow-up actions was developed by Navy in consultation with US EPA and MPCA:

ISSUE RECOMMENDATION OR FOLLOW-UP ACTION

PARTY RESPONSIBLE MILESTONE DATE

1. Employ preventative maintenance practices.

Navy. 1 June 2009

2. Operate system within newly specified operating ranee.

Navy. 1 June 2009

3. Update procurement of O&M contractor.

Navy. 1 June 2009

4. Evaluate system capture in two years to address potential bvoass concerns.

Navy. 1 June 2011

5~ Add NAVFAC technical resources.

Navy, with EPA and MPCA SliPport.

Ongoing

6. Develop Exit Strategy. Navy, with EPA and MPCA support.

Ongoing

7. Track extraction system downtime to verify improvement by system and by well.

Navy. Ongoing

8. i Provide more detailed reporting on system performance.

Navy. Ongoing

9. Continue the Facilitated Partnerina Process.

Navy. Ongoing

10. Perform annual review of adequacy of spare parts inventory.

Navy. Ongoing

See Section 9.0 of the document for additional details.

Protectiveness Statement(s):

The remedy at OU1 currently protects human health and the environment because there are no known completed pathways to receptors. However, for the remedy to be protective in the long-term, hydraulic containment must be maintained and optimal performance of the extraction system must be achieved to ensure long-term protectiveness.

The remedy at OU2 is protective of human health and the environment and in the interim, exposure pathways that could result in unacceptable risks are being controlled.

The remedy at OU3 is protective of human health and the environment and in the interim, exposure pathways that could result in unacceptable risks are being controlled.

Other Comments: None.

F-2 l

Five-Year Review Site Inspection Checklist

-

Five-Year Review Site Inspection Checklist

I. SITE INFORMAnON

Site name: NIROP Fridley Date of inspection: 13 March 08; 05 May 08

Location and Region: Fridley MN Region 5 EPA In:

Weather/temperature: sunny,45;sunny,60F review: US NAVY - Lead Agency Agency, office, or company leading the five-year

Remedy Includes:

Groundwater containment Institutional controls Groundwater pump and treatment

Attachments: none.

U. INTERVIEWS (Check all that apply)

1. O&M site manager _ Paul Walz ___BayWest _05 May 08_ Name Title Date

Interviewed at site Problems, suggestions; Monthly reports are provided detailing status ofoperations and maintenance.

'.,.. 3. Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency response

office, police department, office of public health or environmental health, zoning office, recorder of deeds, or other city and county offices, etc.) Fill in all that apply.

Agency ___none participated in the site inspections.

ill. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)

1. O&M Documents O&Mmanual - Readily available + Up to date As-built drawings N/A (already available as part ofO&M Manual) Maintenance logs Readily available + Up to date Remarks

2. Site-Specific Health and Safety Plan Readily available + Up to date Contingency plan/emergency response plan N/A - critical elements are addressed in SSHASP

3. O&M and OSHA Training Records O&M training and OSHA training records were not evaluated

4.

5.

6.

7.

_.Permits and Service Agreements Air discharge permit N/A - not onsite Effluent discharge N/A - not onsite Waste disposal, POTW N/A - not applicable

Groundwater Monitoring Records Readily available + Up to date

Discharge Compliance Records Air N/A Water (effluent) Readily available Up to date

Daily Access/Security Logs N/A Remarks_Access to all points in the manufacturing plant are controlled at the main gate. The treatment

" area itself is located inside the plant fence and is locked.

IV. O&M COSTS

1. O&M Organization Contractor for PRP

2. O&M Cost Records Readily available Up to date Funding mechanism/agreement in place

COST RECORDS WERE NOT EVALUATED IN DETAIL DURING THE SITE INSPECTION. COSTS WERE ANALYZED IN THE FIVE YEAR REVIEW REPORT DOCUMENT.

3. Unanticipated or Unusually High O&M Costs During Review Period Describe costs and reasons: ___No unancticipated or unusually high costs during the review period

v. ACCESS AND INSTITUTIONAL CONTROLS Applicable A. Fencing

1. Fencing damaged N/A Remarks Fencing is present but is not part of the remedy. Fencing is maintained by the property manager. Fencing was in good condition at the time of the site inspection._

B. Other Access Restrictions

1. Signs and other security measures o Location shown" on site map ON/A Remarks__armed guard coverage at each of the two entrance locations through the fence perimeter

-- ---

C. Institutional Controls (ICs)

l. Implementation and enforcement Site conditions imply ICs properly implemented Yes Site conditions imply ICs being fully enforced Yes

Type of monitoring (e;g., self-reporting, drive by) __self-reporting; inspection visits. Frequency __inspection schedule is irregular, but these generally occur several times per year. _ Responsible party/agency Navy - Lead Agency_ Contact ___Howard Hickey RPM _05 May 08_ 847-688-2600

Name Title Date Phone no.

Reporting is up-to-date Yes Reports are verified by the lead agency Yes

Specific requirements in deed or decision documents have been met Yes Violations have been reported N/A Other problems or suggestions: 01_5/S

'1 "-. Adequacy ICs are adequate

D. General

l. Vandalism/trespassing No vandalism evident

'1.... Land use changes on site None. 3. Land use changes off site 01_5faPt

VI. GENERAL SITE CONDITIONS

A. Roads N/A

B. Other Site Conditions

Remarks The fonner NIROP facility is still engaged in manufacturing and within the context of an active manufacturing facility, there were no noteworthy site conditions.

IX. GROUNDWATER/SURFACE WATER REMEDIES

A. Groundwater Extraction Wells, Pumps, and Pipelines

l. Pumps, Wellhead Plumbing, and Electrical o Good condition o All required wells properly operating Remarks

'1.... Extraction System Pipelines, Valves, Valve Boxes, and Other Appurtenances Good condition

3. Spare Parts and Equipment Readily available; Good condition; ffipgrade in progress

-

C. Treatment System

1. Treatment Train (Check components that apply) Air stripping o Additive (e.g., chelation agent, flocculent) polymers are added to prevent dissolved metals in the groundwater from precipitating out of the ground water in process piping_

Sampling ports properly marked and functional Sampling/maintenance log displayed and up to date Equipment properly identified Quantity ofground,.vater treated annually:_varies - see AMR Remarks none

2. Electrical Enclosures and Panels (properly rated and functional) Good condition Remarks none

3. Tanks, Vaults, Storage Vessels Good condition Proper secondary containment Remarks none

4. Discharge Structure and Appurtenances N/A

5. Treatment Building(s) Good condition (esp. roof and doorways) Chemicals and equipment properly stored

6. Monitoring Wells (pump and treatment remedy) Properly secured/locked Functioning Routinely sampled Good condition

D. Monitoring Data

l. Monitoring Data Is routinely submitted on time Is of acceptable quality

2. Monitoring data suggests: Groundwater plume is effectively contained Contaminant concentrations are declining

XI. OVERALL OBSERVAnONS

A. Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and functioning as designed. Begin with a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume, minimize infiltration and gas emission, etc.).

The remedy requires containment ofa cont3.minant plume (OUI) and LUC (OU2 and OU3). Based on observations, the remedies are effective and functioning as designed.

B. Adequacy of O&M

Describe issues and observations related to the implementation and scope ofO&M procedures. In particular, discuss their relationship to the current and long-term protectiveness of the remedy.

Some minor leaks were observed. The leaking water was captured within secondary containment. The leaks are being addressed via O&M procedures. The leaks to not impact protectiveness.

C. Early Indicators of Potential Remedy Problems

Describe issues and observations such as unexpected changes in the cost or scope ofO&M or a high frequency of unscheduled repairs, that suggest that the protectiveness of the remedy may be compromised in the future.

No early indicators or potential remedy problems were identified during the site inspection. Prior to the site inspection, issues concerning the mechanical performance of the groundwater capture system had already been identified, and these are discussed in detail in the Five Year Review Report.

D. Opportunities for Optimization

Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.

, Opportunities for optimization were not developed during the site visit. These: are, however, discussed in detail in the Five Year Review Report.

--1


Revision: 1 Dale: October 2008

Sectior: 1 Page 1 of 3

'I ........ 1.0 INTRODUCTION

The United States Navy, Naval Facilities Engineering Command Midwest, has conducted a Five-Year

Review of the remedial actions implemented at all Operable Units (OU) at the Naval Industrial Reserve

Ordnance Plant (NIROP) Fridley site in Fridley, Minnesota. This Five-Year Review Report includes the

following:

Determination whether the remedies for OU1, OU2 and OU3 at NIROP Fridley remain protective of

human health and the environment.

Identification of methods and conclusions of reviews.

Identification of issues found during the review, if any, and identification of recommendations to

address them.

Any other information determined by the Navy to be important with regard to the assessment of

protectiveness.

The Navy (Lead Agency) is preparing this Five-Year Review Report pursuant to the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA) Section121 and the National Oil

and Hazardous Substances Pollution Contingency Plan (NCP). CERCLA Section121 states:

If the President selects a remedial action that results in any hazardous substances,

pollutants, or contaminants remaining at the site, the President shall review such

remedial action no less often than each five years after the initiation of such remedial

action to assure that human health and the environment are being protected by the

remedial action being implemented. In addition, if upon such review it is the judgment of

the President that action is appropriate as such site in accordance with section [104] or

[106], the President shall take or require such action. The President shall report to the

Congress a Jist of facilities for which such review is required, the results of all such

reviews, and any actions taken as a result of such reviews.

The United States Environmental Protection Agency (EPA) interpreted this requirement further in the

NCP, 40 Code of Federal Regulations (CFR) 300.430(f)(4)(ii), which states:

"'I ~" ..... '

030810/P 1-1 eTO !502



Section: 1 Page 2 of 3

If a remedial action is selected that results in hazardous substances, pollutants, or

contaminants remaining at the site above levels that allow for unlimited use and

unrestricted exposure; the lead agency shall review such action no less often than every

five years after the initiation of the selected remedial action.

This Five-Year Review is the third Five-Year Review to address OU1 (the groundwater operable unit), but

only the first to address OU2 and OU3 (soils operable units) at NIROP Fridley. This is due to the Record

of Decision (ROD) for OU2 and OU3 having been signed just prior to completion of the second Five-Year

Review Report. The triggering action for this review was the date of signature of the previous five-year

review. The initial triggering event was construction completion for the OU1 remedy. This Five-Year

Review is required due to the hazardous substances, pollutants, or contaminants remaining on site in

excess of levels that allow for unlimited use and unrestricted exposure.

This Five-Year Review was prepared in accordance with EPA's Comprehensive Five-Year Review

Guidance (2001).

The OU2/0U3 ROD was si~lned in September 2003. OU2 generally corresponds to soil outside the main

plant bUilding, and OU3 generally corresponds to soil underneath the main plant building, although the

specific definition is best understood by review of NIROP's 1991 Federal Facility Agreement (FFA). The

selected remedy for both OU2 and OU3 is Land Use Controls. There are no other OUs identified at

NIROP Fridley other than OU1, OU2, and OU3.

The 1991 FFA, primarily addressing OU1, between the United States Environmental Protection Agency

(EPA), Minnesota Pollution Control Agency, (MPCA) and United States Department of the Navy requires

that an Annual Monitoring Report (AMR) be submitted by the Navy to EPA and MPCA each year following

commencement of the groundwater remedial action at NIROP Fridley. The AMR includes summaries and

copies of operating, maintenance, and monitoring data for the groundwater extraction and treatment

system from the previous calendar year. In addition, the Remedial Action Work Plan (RAWP) requires an

annual evaluation of the performance of the extraction well system in achieving hydraulic containment of

contaminated groundwater. The RAWP is a primary document under the FFA which describes how the

Navy will implement the RODs. TheRAWP has been modified from time to time as necessary. Typically,

RAWP modifications are focused on the number and frequency of groundwater monitoring wells subject

to sampling for chemical parameters, in order to support the AMR process.

The cutoff date for data and information for this Five-Year Review is January 10, 2008. Because the

AMR for 2007 analytical and operational data had not yet been drafted and reviewed, the evaluation of

030810/P 1-2 eTa 502



Section: 1 Page 3 Df 3

i..... 2006 groundwater extraction and treatment system data is included in this report. However, based on recent trends the 2007 evaluation is not expected to vary significantly from the 2006 evaluation.

030810/P 1-3 eTa 502

--2

--3


Revision: 1 Date: October 2008 Section: 3

Page 1 Dt 4

3.0 BACKGROUND

NIROP Fridley is located in the northern portion of the Minneapolis/St. Paul Metropolitan Area in an

industrial/commercial area within the city limits of Fridley, Minnesota (see Figures 3-1 and 3-2). The site

is not adjacent to any residential areas. The site is not located in an environmentally sensitive area and is

not near any known environmentally sensitive areas.

Advanced naval weapons systems are designed and manufactured at the NIROP. The northern portion

of the facility was government owned and operated by a private contractor (UDLP - Armament Systems

Division), and the remainder of the facility was owned and operated independently by UDLP. Currently,

ELT Minneapolis, LLC owns the former NIROP property and leases space back to UDLP. The site owm~rs

and occupants are likely to change in the future, but land use is not expected to change. The formerly

government-owned portion of the facility constitutes what is referred to as the NIROP Fridley site.

The site comprises approximately 82.6 acres, most of which is covered with bUildings or pavement. The

site is situated on a broad, flat, glacial drift terrace that is approximately 30 feet above and 2,000 feet east

of the Mississippi River.

Adjacent land use is commercial and light industrial to the north, industrial to the south, recreational to the

west, and commercial/light industrial (including railroads) to the east. The projected land use is the same.

Natural resource use in the area consists of recreational activities in the Anoka County Riverfront

Regional Park (ACP), which is directly west of East River Road from the NIROP site and adjacent to the

Mississippi River. No federal or state freshwater wetlands are located within 1 mile of the site. No critical

habitats of endangered species or national wildlife refuges have been identified near the site. The

groundwater contamination does not limit the public's use of ACP.

The NIROP Fridley site is underlain by an unconsolidated sand and gravel aquifer that overlies a bedrock

aquifer. The water table is 20 to 25 feet below the ground surface in the unconsolidated aquifer, which

has a saturated thickness of approximately 100 feet. A discontinuous clayey glacial till layer is present at

various depths below the ground surface. The underlying bedrock consists of Prairie du Chien Dolomite

and Jordan Sandstone, which are referred to as the PCJ aquifer. The basal unit of the St. Peter

Sandstone that overlies the PCJ aquifer across the northern portion of the site acts as a confining layer

where it is present. Where it is absent, the unconsolidated aquifer is hydraulically connected to the PCJ

aquifer. Groundwater flow in the unconsolidated aquifer is generally from the northeast to the southWi~st

-

030810/P 3-1 CTO 502



Section: 3 Page 2 of4

across the site toward the Mississippi River. The groundwater containment and extraction system has

altered the groundwater flow characteristics.

The City of Minneapolis Water Treatment Plant intake, which draws water from the Mississippi River, is

located less than 1 mile downstream (south) from the NIROP site. Approximately 500,000 people are

served by this treatment plant.

Groundwater in portions of the unconsolidated aquifer beneath NIROP Fridley contains VOCs. The

VOCs typically detected are listed as follows (from greatest frequency detected to least detected): TCE,

cis-1,2-DCE, trans 1,2-DCE, 1,1-dichloroethane (1,1-DCA), 1,1 DCE, PCE, vinyl chloride, and 1,1,1 TCA.

The concentrations vary widely across the site; however, TCE has been detected more frequently and at

higher concentrations than any other VOC. TCE is therefore assumed to be the primary indicator

parameter for monitoring contamination and the remedial system at NIROP Fridley. Results of laboratory

analyses of samples collected from groundwater monitoring and extraction wells during each calendar

year are presented and discussed in the AMR issued for that year.

During the early 1970s, paint sludges and chlorinated solvents generated from ordnance manufacturing

processes were disposed in pits and trenches in the North 40 area, which is the undeveloped NIROP

owned area immediately north of the plant. Contaminant sources in the North 40 and beneath the NIROP

building wee not detected until December 1980, when MPCA received information concerning past waste

disposal practices at NIROP. Results from groundwater sampling in March and April 1981 indicated that

TCE was present at 200 IJg/L in two on-site NIROP water supply wells, and in December 1981, TCE was

detected in Mississippi River water at the City of Minneapolis water treatment plant intake at 1.2 IJg/L.

The intake is located less than half a mile downstream from NIROP. The Safe Drinking Water Act

(SDWA) Maximum Contaminant level (MCl) for TCE is 5.0 IJg/l. In April 1981, the NIROP water supply

wells were shut down and a municipal water supply was connected to the plant.

In May 1983, an lAS identified that drummed wastes were disposed of in the northern portion of the

NIROP (North 40). Groundwater monitoring wells were installed and sampled in the area to investigate

potential impacts from drum disposal. From November 1983 to March 1984, approximately 1,200 cubic

yards of contaminated soil and 43 drums were excavated and disposed. An RifFS was conducted from

June 1986 to May 1989. The NIROP site was listed on the NPl in November 1989. Following the RifFS,

a Proposed Plan to hydraulically contain TCE-contaminated groundwater was presented to the public.

Phase I treatment of extracted groundwater was to be conducted at a local PUblicly Owned Treatment

Works (POTW). Phase II treatment involved onsite treatment with discharge of treated water in

030810/P 3-2 eTa 502




'H"" accordance with an NPDES discharge permit to the Mississippi River. The ROD for OU1 addressing groundwater contamination through hydraulic containment and treatment was signed in September 1990.

The first Five-Year Review was drafted by EPA and signed by the Navy as lead agency in October 1998.

The first Five-Year Review determined that remedial action for OU1 continued to be protective of human

health and the environment. The residual groundwater contamination in ACP would be further evaluated

by the implementation of recommendations in the Five-Year Review report. These recommendations

were recounted in Section 5 of the Second Five-Year Review (reference), and are repeated in Section 5

of this Five-Year Review.

A risk assessment for OU2 was conducted in 1996. Following a revision of that risk assessment, it was

determined that risk in one subarea of OU2 was inordinately influenced by a single data point. Therefore,

during the summer of 2002, the Navy conducted a time-critical removal action to remove approximately

35 cubic yards of soil around this location with concentrations of VOC contaminants that exceeded

regUlator Clean-up levels. This removal was completed in June 2002 and addressed the only remaining

location with unacceptable risks for surface soil. A ROD was signed in September 2003 for OU2 and

OU3 requiring land use restrictions and ensuring the concrete pit floor located in the former Plating Shop

is not removed without prior regulatory approval to prevent unacceptable worker exposures.

A field stUdy consisting of the installation of injection and monitoring wells, baseline sampling, vegetable

oil injection, and follow-up monitoring was conducted from October 2001 to November 2005. A total of

3,600 gallons of refined soybean oil and 7,200 gallons of native groundwater were injected into three

injection wells in December 2001. Additional monitoring wells were installed and additional soil sampling

was conducted in March and April 2005 to improve tracking the pilot test performance.

The results of the pilot study indicated that the addition of the organic substrate was successful in

creating conditions conducive to reductive dechlorination of chlorinated volatile organic compounds. The

Vegetable Oil Pilot Project Report (Parsons, 2006) acknowledged that the induced "geochemical chan~les

(were) neither spatially uniform nor temporally consistent." Nevertheless, significant reductions in

chlorinated solvent concentrations were observed in the pilot test area. As a result, the Vegetable Oil

Pilot Project Report concluded that "the vegetable oil pilot test has been successful in enhancing the

destruction of chlorinated solvent mass in the subsurface and has thus been successful in reducing the

overall toxicity of the groundwater plume." The authors of the Vegetable Oil Pilot Project Report

recommended that "organic substrate addition in general and vegetable oil injection specifically be

considered as a future remedial option at this site." The authors of the report have also recommended

that the application of this technology be limited to "defined contaminant hot spots or source amas

030810/P 3-3 CTO 502




instead of attempting to treat large areas." The report also acknowledged that the decision to implement

the vegetable oil technology in ACP can only be made within the context of other factors, such as the

decreasing levels of contamination recently observed in ACP due presumably to recent upgrades in the

extraction system.

030810/P 3-4 eTO 502

1500 j

DRAWN BY

K.PEILA

DATE

9124102

o

~ Tetra Tech NUS, Inc.

N

CHECKED BY DATE

J. MAGILSON 9124102

SITE LOCATION MAPCOST/SCHEDULE-AREA NIROP FRIDLEY, MINNESOTA

AS NOTED

APPROVED BY

M. SLADIC

DATE

9/24/02

APPROVED BY DATE

DRAWING NO.

FIGURE 3-1 REV

o P:\GIS\NIROP_FRIOLEY\7842_AMR2000.APR\FACIUTY MAP LAYOUT 4/02108 55

f0-Ci:

t.... :::IE

_. 4

4.1




4.0 REMEDIAL ACTIONS

ESTABLISHMENT OF OUS

Three OUs have been identified at NIROP Fridley. Groundwater is identified as OU1. The land outside

of the main NIROP manufacturing building but within the legal boundaries of the facility, from the ground

surface to groundwater elevation (Le., the water table), has been identified as OU2. The land under the

main NIROP building, and soil at elevations below the water table elevation (the saturated zone) either

under the building or outside the building but within the legal boundaries of the facility has been

designated as OU3. The ROD for OU1 was signed in September 1990, and the first Five-Year Review

was signed in September 1998; the second Five-Year Review was signed in October 2003. The ROD for

OU2 and OU3 was signed in September 2003, and was therefore not addressed in significant detail in the

second Five-Year Review. Additional chronology details are provided in Section 2 of this Five-Year

Review.

4.2 OU1 REMEDIAL ACTIONS

The remedial action specified in the 1990 OU1 ROD was 'hydraulic containment and recovery of all future

4'11"" migration of contaminated groundwater from the NIROP and the recovery, to the extent feasible, of

groundwater contamination downgradient of the NIROP'. The selected remedy included installation and

operation of groundwater containment and extraction wells with a two-phased plan for disposal of

groundwater from the well system. Contaminated groundwater remains downgradient of the NIROP

facility in ACP. Although no time frame for dissipation was provided in the ROD, to date it is not apparent

that natural dissipation of this groundwater contamination is occurring as predicted in the ROD.

The failure of the contamination in Anoka County Park to fUlly dissipate as envisioned by the ROD may

be due to operational problems with the extraction system. There also remains some potential for

continued but limited contaminated groundwater to be bypassing the extraction system. However,

significant improvements in the groundwater quality in ACP have occurred after the 1995 and 2001

upgrades to the extraction system as the extraction system intercepts most of the site-related

contamination when it is fully operational. For example, maximum TCE concentrations over all aquifer

zones in ACP before 1996, between 1996 and 2001, and after 2001 were, respectively, 21500 IJg/L,

25000 IJg/L, and 5300 IJg/L. The increase in maximum TCE concentration from before 1996 and between

1996 and 2001 is due to the additional data from the new monitoring wells in probable source areas

installed between 1996 and 2001. Since the 2001 upgrade to the system, the maximum TeE

concentration in ACP has decreased by 79 percent.

030810/P 4-1 eTO 502

NIROP Fridley FiveYear Review



4.2.1 Phase I of OU1 Remedial Actions

During Phase I of the groundwater extraction remedy, groundwater from the extraction system was

discharged to an existing sanitary sewer system for treatment at the local Pig's Eye publicly owned -./

treatment work (POTW). During Phase II, a groundwater treatment system was constructed and is being

operated to provide longer-term groundwater treatment. Treated groundwater from the onsite treatment

facility is discharged to the Mississippi River through an NPDES/State Disposal System (SDS) permitted

outfall (Outfall 020).

The groundwater extraction system and pretreatment facilities began operating in September 1992.

Monitoring of these facilities and associated monitoring wells has been performed since startup according

to the procedures described in the 1995 RAWP for Groundwater Remediation as approved by EPA and

MPCA. The RAWP document has been subsequently revised, most recently in September 2005, to

refine the number and frequency of monitoring wells specified for sampling.

As required by the ROD, an evaluation of the effectiveness of the groundwater extraction system in

achieving hydraUlic containment of contaminated groundwater from the site during the initial 90-day

operating period was submitted to EPA and MPCA in December 1992 (RMT, 1992). The evaluation

concluded that additional groundwater extraction well(s) would be needed to achieve effective hydraulic

containment. A work plan for upgrading the original extraction system was prepared and approved by

EPA and MPCA (reference). Two additional extraction wells were installed and placed into operation in

June 1995. At that time, the combined groundwater extraction system consisted of six wells. With the

approval of the MCES. the, pretreatment system was shut down in March 1995, and the combined

discharge from the extraction wells has since been transferred directly to the sanitary sewer.

4.2.2 Phase II of OU1 Remedial Action

Construction of the Phase II onsite groundwater treatment facility began in September 1997 and was

completed and the facility began operation in December 1998. The discharge to the MCES sanitary

sewer system no longer occurs, and treated groundwater from this facility is now discharged to the

Mississippi River through Outfall 020 (NPDES/SDS Permit MN0000710).

The OU1 groundwater containment and extraction system currently consists of seven pumping wells and

related piping and appurtenances. A site plan showing the approximate locations of the extraction wells

and associated facilities is presented as Figure 3-2. The ROD does not list remedial action objectives;

030810/P 4-2 eTa 502



Section: 4. Page 3 of 10

'I~, ....I however, it states that the objective of the selected alternative is to address the principle threat posed by the site by providing hydraulic containment to prevent further migration of contaminated groundwater from

the NIROP and by recovering, to the extent feasible, contaminated groundwater beneath ACP. The ROD

further states that the initial goal of the selected alternative is to contain contaminated groundwater from

both the NIROP and, to the extent feasible, ACP, and that the ultimate goal is to restore groundwater

quality in the unconsolidated aquifer at the site to MCLs. The ROD also states that USEPA has

determined that MCLs are relevant and appropriate standards for ground water unless, under

circumstances at the site, more stringent standards must be applied to ensure protection of public health

and the environment.

The current extraction wells are identified as well numbers AT-3A, AT-SA, AT-SB, AT-7 AT-8, AT-9, and

AT-10. The wells are located and constructed to contain and extract contaminated groundwater along the

southwestern (downgradient) portion of the NIROP site.

A schematic diagram showing the components of the groundwater extraction and treatment facilities is

presented as Figure 4-1. The discharge from each of the seven extraction wells is routed via separate

forcemains to a Control House located near the security fence on the western side of the plant.

Instrumentation provided at the Control House includes a flow rate indicator and a flow volume totalizer

for each extraction well discharge. The combined discharge from the seven extraction wells flows via a

single pipe to a Treatment Building located near the Control House. Sampling ports are located on the

piping for each extraction well and on the combined discharge to the Treatment Building.

The major components of the current treatment system include a feed tank, air stripping units, and an

effluent system. The feed system consists of an equalization tank to collect groundwater pumped from

the extraction well system and feed pumps to convey the groundwater from the equalization tank to the

air strippers. Four low-profile, tray-type air strippers are operated in parallel. The effluent water flows by

gravity to the effluent sump, and the exhaust air is vented to the atmosphere. Effluent pumps convey the

treated water from the effluent sump to an existing 72-inch-diameter storm sewer that discharges to the

Mississippi River through NPDES/SDS Outfall 020.

There are no air emission controls for the air strippers. In 2001, the air emission rates (AERs) for the

groundwater treatment facility (GWTF) were updated. The Navy determined that the emission rates from

the GWTF operation were within the site-specific AERs. Site-specific AERs are emission rate limits that

ensure that maximum offsite ambient air impacts are less than regUlatory-defined allowable offsite

concentrations (Le., that would result in cancer risk to the potential offsite receptors of greater than 1 X

10-5). Site-specific AERs were calculated for carcinogenic compounds that could potentially be emitted

030810/P 4-3 GTO 502




from operation of the groundwater treatment facility. The approach involved using the EPA-approved

Industrial Source Complex Short-Term, Version 3 (ISCST3) (Revision 2) atmospheric dispersion model to

"back model" from the maximum allowable offsite impact to annual average site-specific AERs. The site

specific AERs and maximum groundwater production rate were then used to calculate maximum

allowable concentrations for groundwater entering the treatment facility. In this manner, groundwater

concentrations were used to predict air emissions so that measurement of air emissions was not required.

The conservatively estimated allowable groundwater contaminant concentrations were all significantly

greater than measured groundwater concentrations. Therefore, no emission control measures were

required for the GWTF. Actual samples of the air stripper influent and effluent were collected during start

up of the GWTF to confirm that site-specific AERs were met. Additional samples of groundwater influent

and effluent are collected to meet NPDES permit requirements. Based on these data, AERs have not

been exceeded in the 5-year period addressed by this Five-Year Review, or in the period addressed by

the second Five-Year Review.

4.2.3 OU1 Performance Measurement

Table 4-1 identifies OU1 groundwater chemicals of concern (COCs) and their respective MCLs pursuant

to the federal Safe Drinking Water Act (SDWA). This table also identifies the state Health Risk Limits for

these COCs.

Table 4-2 identifies the current OU1 groundwater treatment system COCs, their respective daily

maximum concentration limits as identified in the facility's NPDES/SDS Permit and the ranges of

concentrations of each cae detected during the last NPDES/SDS permit sampling event.

Table 4-3 identifies the current COCs for OU1. A subset of 17 monitoring wells located in ACP nearest

the bank of the Mississippi River have been agreed between Navy, EPA and MPCA to be used as

measurement points for compliance (compliance wells) for the purpose of identifying groundwater COC

concentrations potentially migrating into the river. This is due to the Navy, EPA and MPCA not being able

to concur on a representative sampling approach actually in the river or at the riverbank interface

including the Navy's desire to consider a mixing zone and MPCA's requirements for protecting surface

water. Table 4-3 identifies the respective To-Be-Considereds (TBCs). TBCs are the same as the surface

water treatment system COCs and their respective ARARs; however, the Minnesota TBCs for TCE

include the following: the drinking water and fish consumption criterion of 25 ~g/L; the acute maximum

aquatic life standard of 2,500 ~g/L; and the final acute aquatic life criterion of 5,000 ~g/L - see Attachment

I to the Five-Year Review, dated October 27, 1998); and the range of concentrations of each COC

~I'"

030810/P 4-4 eTO 502




~'f"..." detected during the last appropriate sampling event in the compliance monitoring wells used for

monitoring the discharge of contaminated groundwater to the river.

As stated by the ROD, "[t]he remedy will comply with the ARARs by meeting the MCl for TCE as the

target cleanup level for the site. The alternative [OU1 remedy] will reduce the toxicity, mobility, and

volume of TCE in the aquifer. By meeting the MCl for TCE, other VOCs will also be reduced

proportionately." The objectives of groundwater monitoring, as further interpreted in the September 2005

RAWP, are as follows:

Evaluate the ability of the groundwater extraction system to effectively contain downgradient

migration of contaminants and provide water quality improvement;

Assess the potential for contamination from onsite sources and upgradient (offsite) sources;

Evaluate air stripper emissions to the atmosphere;

Evaluate whether the remedy complies with the ROD;

Evaluate whether the remedy is protective of human health and the environment;

Evaluate the progress of the remedy in achieving the goals specified in the ROD;

Evaluate whether project permit requirements are met;

Evaluate the relative contaminant concentrations along the flow path in relation to the following:

upgradient groundwater conditions; known and potential source areas; capture and non-capture of

the groundwater contaminant plume; residual contamination beyond the effectiveness of the capture

of the remedial system and discharge to the river; and vertical head relationships and the potential

flow bf contaminants from one aquifer interval to another.

The objectives for the monitoring system were originally refined based on the data quality objectives

(DOOs) decision-making process that was executed by the NIROP Partnering Team. Meetings held on

March 19 to 23, 2001, July 17 to 19, 2001, and March 6 to 7, 2002 were used to better define the

objectives and formal decision-making process for the site. As determined at these meetings, "000

Problem C: Groundwater Monitoring for Overall Contamination at NIROP" defined six items that should be

030810/P 4-5 eTO 502




addressed, at least in part, by groundwater monitoring at this site. These items are generally defined as '"'-'

follows:

1. Determination of capture system performance.

2. Determination of contaminant concentrations at Mississippi River compliance wells.

3. Determination of chang'9s in the plume shape, size, and location.

4. Determination of contaminant concentrations relative to surface water and groundwater standards..

5. Determination of capture system performance, evaluation of system modifications, evaluation of

alternative approaches, evaluation of technical impracticability, and/or an alternative concentration

limit (ACL).

6. Determination of the practicability of the remedy and evaluation of an ACL.

4.2.4 OU1 Operations and Maintenance

Air stripper emissions to the atmosphere are evaluated using site-specific AERs established to ensure

that maximum offsite ambient air impacts are less than regulatory-defined allowable offsite

concentrations. Table 4-4 presents the allowable air concentrations, AERs, and allowable groundwater

concentrations. The allowable groundwater concentration is the level, determined based on modeling

that will not cause the allowable air concentration to be exceeded.

A trained operator oversees operation of the water treatment process. The current site O&M manual has

been converted to electronic: media for ease of access and future updates.

The Navy develops and maintains monthly Treatment System Reports detailing the wastewater treatment

plant (WWTP) O&M. These reports include a narrative overview, recap of scheduled maintenance,

summary of problems and solutions, and operating statistics. Operating statistics including monthly and

cumulative treated water volumes, electrical meter readings, and a calculated on-stream factor are

provided in tabular form and in graphical form. Monthly status reports are provided to EPA and MPCA.

Current annual O&M costs for treatment plant operation are approximately $400,000 but continue to vary

from year to year based on the occurrence of unexpected significant mechanical item replacement. For

fiscal years 2006 and 2007, the Navy has expended in excess of $150,000 more than routine O&M costs

for preventative maintenance and to replace aging components, buy and install new pumps, and stock

critical spare parts in order to minimize system downtime.

030810/P 4-6 GTO 502




~,,~_. It is not meaningful to compare current O&M costs to anticipated costs developed prior to the 1990

remedy selection for the following reasons:

The original design anticipated use of granular activated carbon (GAG) to treat the air from the

strippers. To date, based on groundwater contamination, resulting air emissions from the strippers

have not warranted the use of GAG. Therefore, costs have not been incurred for use and periodic

replacement of GAG.

Two new pumping wells, AT-SA and AT-5B, were added in 1995 to improve system performance.

The plant capacity has been increased to approximately 850 gallons per minute (gpm) from

approximately 600 gpm (from the 1990 design).

Biological iron fouling has resulted in significantly increased maintenance requirements for pumps

and well screens.

Mineral hardness fOUling of pipes and appurtenances has resulted in significantly increased

maintenance requirements for cleaning and replacement of these components. A food-grade

polymer addition system to prevent mineral deposits does mitigate this situation, somewhat, for

downstream units.

Recently, the system has experienced an increase in interruptions to flow rates, primarily caused by

fouling of wells or other equipment failure. The most significant disruption in pumping durations was

reported to be caused by fouling of the extraction wells. Other interruptions to individual components or

system-wide shutdowns were caused by mechanical and electrical problems. These interruptions have

necessitated the replacement of transducers, reprogramming of flow meters, and replacement of the air

flow sensor-pressure transducer tubing. Evaluation of the system is continuing by the Navy and by

manufacturer representatives to address these issues. There are no indications that these failures have

impaired the long-term performance of the system or resulted in any increased risk to human health or

the environment. However, the potential exists for these extraction rate reductions to limit capture during

periods when the system is malfunctioning. Evaluation of the impact of these failures on the long-term

performance of the system is continuing.

The ROD specifies that the Navy will control health risks in the future by implementation of a groundwater

treatment system or other appropriate measures if a water supply well system is installed in AGP. To

030810/P 4-7 CT0502

NIROP Fridley Five_Year Review



date, no additional water supply systems have been installed in ACP; therefore, this component of the

remedy has not been necessary.

4.2.5 OU1 Vegetable Oil Pilot Testing

A Vegetable Oil Pilot Study was initiated in December 2001 to determine whether a full-scale vegetable

oil injection remedy could re!mediate contaminated groundwater in the park. GroundWater monitoring was

conducted for approximately 1 year subsequent to the injection, and the results were summarized in the

Final Report for a Field Application to Enhance In-Situ Bioremediation of Chlorinated Solvents via

Vegetable Oil Injection at NIROP, MN (Parsons, 2006). The results of the monitoring indicated that the

pilot study was somewhat successful in accelerating biologically mediated reductive dechlorination of

chlorinated ethenes. However, it was also determined that vegetable oil-derived organic carbon was not

effectively distributed within the pilot test area and that complete reductive dechlorination was only

induced in a relatively small area.

4.3 OU2 AND OU3 REMEDIAL ACTIONS

The remedial action specified in the August 2003 ROD for NIROP's OU2 and OU3 was Land Use

Controls (LUC), consisting of both Engineering Controls and Institutional Controls. The LUC performance

objectives from the ROD are:

To restrict the use of the Property to industrial or restricted commercial use, until and unless EPA and

MPCA determine that concentrations of hazardous substances in the soils have been reduced to

levels that allow for a less restrictive use.

To prohibit the disturbance of soils deeper than 3 feet below ground surface in those Designated

Restricted Areas shown in Figure 2-5 or the removal of any soils excavated in those Areas from the

facility without the prior written approval of the U.S. EPA and MPCA.

To prohiqit the disturbance of soils beneath the Designated Restricted Area known as the concrete pit

foundations where metal-finishing operations previously occurred at the former Plating Shop within

the Main Manufacturing Building without the prior written approval of the US EPA and MPCA.

To ensure that the concrete pit floor (approximately 8 to 12 feet below grade floor) where metal

finishing operations previously occurred at the former Plating Shop within the Main Manufacturing

030810/P 4-8 eTO 502




Building is not removed without the prior written approval of U.S. EPA and MPCA. That floor will

serve as an Engineering Control.

The ROD states that the Property will be restricted to only industrial or restricted commercial uses.

Industrial property uses generally include, but are not limited to, the following types of uses: public utility

services, rail and freight services, raw storage facilities, refined material storage facilities, and

manufacturing facilities engaged in the mechanical or chemical transformation of materials or substances

into new products.

The ROD also states that restricted commercial use is defined as use where access or occupancy by

non-employees is less frequent or is restricted, including a wide variety of uses, ranging from non public

access and both outdoor and indoor activities (e.g., large scale warehouse operations), to limited public

access and indoor office worker activities (e.g., bank, dentist office). In general, restricted commercial

property use excludes uses such as day-care centers, churches, social centers, hospitals, elder care

facilities, and nursing homes. The resulting LUCs are incorporated into the deed, and these restrictions

run with the land such that any subsequent owner is bound by the same restrictions.

The risk assessment summary which necessitated remedial actions is provided as Table 4-5. COCs for

OU2 and OU3 are identified in the table. A LUC remedial design was finalized in March 2004, which

provided information on how the remedy would be implemented, maintained, and enforced, should any

breach of the remedy occur.

As of the cutoff date for data and information in this Five Year Review (January 10, 2008). the LUC for

OU2 and OU3 remain in force, and no breach of the remedy has occurred. The Navy has informally

confirmed OU2 and OU3 LUC compliance throughout the review period.

A formal inspection using a checklist based on an example in the EPA Five-Year Review gUidance was

conducted on March 13, 2008 for all three OUs. MPCA representatives accompanied Navy on the

inspection but did not assume a formal role in the inspection. No significant issues were identified during

the inspection. This was not unexpected by the Navy, since the OU1 groundwater extraction system

requires intense operator interface, which results in frequent communication between the O&M contractor

and the Navy. In other words, the system operators are already in regular communication with Navy to

address issues as they emerge. This was also not unexpected for OU2 and OU3 as Navy personnel

have had frequent opportunity to visit the facility throughout the review period and could plainly observe

that the LUC at OU2 and OU3 were being maintained and enforced.

'.030810/P 4-9 GTO 502



Page 10 of 10 Section: 4

A follow-up inspection was conducted on May 5,2008 for all three GUs by Navy and EPA. MPCA was

invited to participate but declined. Navy was represented by Howard Hickey, and EPA was lead by Tom

Smith, and both were supported by contractor personnel, No breaches of the remedy were identified,

030810/P 4-10 CTO 502

TABLE 4-1

GROUNDWATER CHEMICALS OF CONCERN AND TARGET CLEANUP LEVELS OU1 - OCTOBER 2006 SAMPLING 'EVENT

NAVAL INDUSTRIAL RESERVE ORDNANCE PLANT FRIDLEY, MINNESOTA

Parameter Maximum Contaminant Level (lJg/L)

Health Risk Limit (lJg/L)

1,1-Dichloroethane - 70 1,1-Dichloroethene 7 6(1)

cis-1,2-Dichloroethene 70 70

trabs-1,2-Dichloroethene 100 100

Tetrachloroethene 5 7

1,1,1-Trichloroethane 200 600

Trichloroethene 5 30(2)

Vinyl chloride 2 0.2

Maximum Contaminant levels (MCls) per 40 CFR 141. - MCl not available. Health Risk Limit (HRl) per Minnesota Rules 4717.7100-4717.7800. 1 - A value of 80 IJgll has been proposed for 1,1-dichloroethene. 2 - Although a HRl was promulgated for trichloroethene, due to research that has

become available since the HRls were promulgated, the Minnesota Department of Health no longer recommends the HRl value.

'I .....

TABLE 4-2

CURRENT GROUNDWATER TREATMENT SYSTEM CHEMICALS OF CONCERN OU1 - OCTOBER 2006 SAMPLING EVENT


PARAMETER NPDESISDS PERMIT LIMITS (",giL)

RANGE OF CONCENTRATIONS

Oct - Dec 2007 (pg/L)

7.7 - 8.3 SU

ND

ND

ND

NO

ND

ND

ND

ND

pH 6.0 - 9.0 SU

1,1,1-Trichlqroethane 200

1,1-Dichloroethane 70

1,1-Dichloroethene 6

trans-1,2-0ichloroethene 100

cis-1,2-Dichloroethene 70

Methylene Chloride 5

Tetrachloroethene 3.8

Trichloroethene 5

SU - Standard Units ND - Not Detected 1 J.Ig/L)

TABLE 4-3

DETECTED CONCENTRATIONS OF VOCs IN COMPLIANCE WELLS OU1 - OCTOBER 2006 SAMPLING EVENT


Volatile Or anic Compounds /IMN SW Criteria(1 ) (giL) TCE I ChloridePCEcis-1,2-DCE

0.173.8 2570Chronic Standard NA428 6,988NAMaximum Standard

857 13,976 NANAFinal Acute Value 5 25Domestic Consum tion

Wells in the Shallow Monitorin 27-S NO 0.07 J

MS-43S NO 0.11 J MS-44S NO NO MS-47S 0.71 NO MS-49S 0.57 NO USGS-5 NO

uifer

Wells in the Intermediate Monitorin 16-IS 2

MS-431 NO MS-441 NO MS-471 2.4 MS-491 2.3

Wells in the Dee Monitorin

.1-' 16-0

MS-430 NO

0.08 J MS-440 0.11 J MS-470 NO MS-49D NO

Wells in the PC Bedrock AquiferI MS-48PC 1.9 0.4 J 0.49 J 3.6 0.08 J 1. Minnesota Surface Water Criteria source: http://www.revisor.leg.state.mn.us/aruleI705010220.html.

Minnesota Rule 7050.0220. Specific Standards of Quality and Purity By Association Use of Classes Chronic Standard -

Maximum Standard -

Final Acute Value -

Domestic Consumption -NA - Not applicable NO - Not detected. NS - Not sampled. J - Estimated quantity.

The highest water concentration of a toxicant to which organisms can be exposed indefinitely without causing chronic toxicity. The highest concentration of a toxicant in water to which aquatic organisms can be exposed for a brief time with zero to slight mortality. An estimate of the concentration of a pollutant corresponding to the cumulative probability of 0.05 in the distribution of all the acute toxicity values for the genera or species from the acceptable acute toxicity tests conducted on a pollutant. Standard for domestic consumption of Class 1 drinking water.

Shaded results indicate an exceedance of Minnesota Surface Wafer Criteria.

http://www.revisor.leg.state.mn.us/arule/7050/0220.html

TABLE 4-4

SITE-SPECIFIC ALLOWABLE AIR EMISSION RATES AND GROUNDWATER CONCENTRATIONS NAVAL INDUSTRIAL RESERVE ORDNANCE PLANT

FRIDLEY, MINNESOTA

Parameter Allowable Air Concentrations

(J,Jg/m3)

Allowable Air Emission Rate

(J,Jg/sec)

Allowable Groundwater

Concentration (J,Jg/L)

1,1-Dichloroethane 500 1.35E+8 2,100,000

1,1-Dichloroethene 0.2 5.4E+4 850

Methylene chloride 20 5.4E+6 85,000

Tetrachloroethene 17.2 4.6E+6 73,000

Trichloroethene 5.9 1.6E+6 25,000

.. !

l i

ACAD: 7842GF02.dwo 09/04/02 HJB PIT

BY CHKO APPO REFERENCES ORA~ BY 1/./iTE

~ HJB 9 4 02 ~ ~,f

CHECKED BY DATE

t*~ GROUNDWA1ER EXTRACTION AND APPROVED BY DATE

TREAn.tENT SYSlEtof COST/SCHED-AREA NAVAL INDUSTRIAL RESERVE ORDNANCE PLANT APPROVED BY DATE

I I ~Jl! FRIDlEY. MINNIESOTA SCAlE 4-... ~ DRAYI1NG NO. IREtNOT TO SCALE J:lt7unutt-~ FIGURE 4-1

AIR STRIPPER

204

AIR STRIPPER

203

AIR STRIPPER

202

r-----------~-----__-TO STORM SEWER

[J(

EVACUATION SUMP S-301

AIR STRIPPER

201

EQUALIZATION TANK T-101

' "" u U ANTI-SCALE

POLYMER

( fllRH C:ADD NO. SDIV_BH.DIoIG REV 0 - 1/20/98

U EXTRACTION WEll

AT-3A

U EXTRACTION WELL

AT-:-5A

U EXTRACTION WELL

AT-58

U EXTRACTION WEll

AT-7

a : EXTRACTION WELL

AT-B

U EXTRACTION WELL

AT-9

U EXTRACTION WEll

AT-10

NO. DATE RE\IlSlONS

--~




5.0 PROGRESS SINCE THE LAST FIVE YEAR REVIEW

5.1 OU1 PROGRESS SINCE THE LAST FIVE YEAR REVIEW

The protectiveness statement from the previous Five-Year Review Report (signed by EPA on October 31,

2003) was as follows:

Overall the remedial action for Operational Unit 1 continues to be protective of human

health and the environment by preventing further migration of contaminated water off the

NIROP facility and continuing to restore ground water quality in the unconsolidated

aquifer at the site. Contaminated ground water remains downgradient of the NIROP

facility in Anoka County Park and it is not naturally dissipating as envisioned in the ROD.

As discussed in Section 9.0, a Vegetable Oil Pilot Study is currently underway to

determine whether or not a full-scale vegetable oil injection remedy can [be] implemented

to enhance the remedy regarding the contaminated ground water in the park.

The Second Five-Year Review Report included the following recommendations:

Extraction of Contaminated Groundwater: The pump and treat system must remain in

operation, as key groundwater contaminant concentrations continue to exceed Federal

MCLs.

Vegetable Oil Pilot Study: The Navy will continue the Vegetable Oil Pilot Study in Anoka

Park. Upon successful completion of the study, use of that technology may be

expanded. The Navy, EPA, and MPCA are in agreement on the DQOs that must be

satisfied to consider a successful completion to the study. In order to confirm favorable

treatment trends, the Navy has already extended the study schedule. At this time, the

final round of groundwater sampling for the study is scheduled for August. Several

months after the sampling, the Navy will provide EPA and MPCA with a summary report

with recommendations. Following the completion of the study, the Navy may recommend

extending the treatment zone, or may propose that an alternative technology be

considered for testing, or some other option.

USGS Groundwater Capture Evaluation: The Navy is providing EPA and MPCA with a

highly-technical groundwater capture evaluation prepared by USGS. Preliminary

',

030810/P 5-1 eTO 502



Section: 5 Page 2 of 7 _.

conclusions from the capture analysis include consensus that the evaluation did not

warrant additional pumping at this time; that the annual monitoring performed at the site

would be reviewed on a yearly basis and that trends in downgradient contaminant levels

would be used as another evaluation tool to monitor the effectiveness of capture (as

decided in the DQO process). In addition, field tests should proceed to resolve which

aquifer zones several monitoring wells should be assigned to. The Navy agreed to install

a nest of monitoring wells, including a shallow and intermediate well, downgradient of

AT-3A to serve as "sentinel" wells to monitor the downgradient impact of AT-3A. The

Navy will also continue to provide a capture evaluation discussion in each year's AMR,

ultimately incorporating the USGS work as appropriate.

The Navy will continue the following activities:

Operation, routine maintenance, and repair of the OU 1 remedy to meet ROD

objectives.

Operation of and monitoring the performance of the au 1 remedy according to the NPDES permit requirements to determine if surface water quality standards required

in the plant discharge have been met.

Calculation and reporting of site emission rates of airborne treatment system COCs

to ensure that the AERs are not being exceed~d.

Sampling and reporting data from surface water compliance wells and comparison of

the results to determine whether or not surface water TSCs for the Mississippi River

are met prior to plume discharge to the river.

Monitor hydraulic heads, ground water chemistry, chemical trends, and pumping

rates according to reporting requirements of the Annual Monitoring Reports.

If the Vegetable Oil Injection Pilot StUdy is not successful, the Navy will then reevaluate

the adequacy of the pilot study and/or evaluate alternative remedies.

In response to these recommendations, the Navy has continued operation and maintenance of the

groundwater treatment system.

030810/P 5-2 eTO 502




The following activities occurred to monitor and maintain protection from groundwater contamination in

ACP:

An expanded inventory of containment system spare parts is now being stocked on site.

Sampling has occurred at numerous wells. The groundwater monitoring plan has been expanded.

Site emission rates of airborne treatment system COCs were monitored to ensure that AERs were not

exceeded.

Chemical trends were analyzed using the EPA-recommended statistical method, the Mann-Kendall

Test for Trend.

Pumping rates were monitored and recorded. The cumulative amounts of TCE and total VOCs

removed by the system from 1992 through 2006 were approximately 30,900 pounds and

34,600 pounds, respectively, based on a cumulative pumping volume of approximately 3.2 billion

gallons.

MPCA previously determined that groundwater contamination exceeds surface water quality criteria,

although river samples have not been collected. Groundwater contaminant concentrations measured

at the agreed line of compliance wells nearest the river continue to exceed surface water quality

criteria since the previous Five-Year Review. However, intermittent, but sometimes long-lived,

mechanical and electrical operational issues with the groundwater extraction system have likely

worked against any mechanisms that would improve the groundwater quality in this area. Although

many of the mechanical and electrical operational issues identified in the Second Five Year Review

have been resolved, some remain and additional mechanical and electrical issues have occurred.

MPCA's surface water quality criteria are generally more stringent than Federal MCLs, and as such

until the groundwater is in compliance with MCLs it will remain out of compliance with the surface

water quality criteria.

An enhanced in-situ bioremediation pilot test using vegetable oil was initiated in December 2001 by

the Navy to evaluate the potential of this technology to remediate chlorinated aliphatic hydrocarbons

(CAHs) in groundwater in ACP. Groundwater monitoring was conducted for approximately 1 year

after injection of food-grade soybean oil and native groundwater into the aquifer, and the results were

-

030810/P 5-3 eTO 502



Section: 5 Page 4 of?

summarized in the Final Report for a Field Application to Enhance In-Situ Bioremediation of

Chlorinated Solvents via Vegetable Oil Injection at NIROP, MN (Parsons, 2006). The results of the

pilot study indicate that the addition of the organic substrate was successful in creating conditions

conducive to reductive dechlorination of chlorinated volatile organic compounds. The Vegetable Oil

Pilot Project Report acknowledged that the induced "geochemical changes (were) neither spatially

uniform nor temporally consistent." Nevertheless, significant reductions in chlorinated solvent

concentrations were observed in the pilot test area. As a result, the Vegetable Oil Pilot Project

Report concludes that "the vegetable oil pilot test has been successful in enhancing the destruction of

chlorinated solvent mass in the subsurface and has thus been successful in reducing the overall

toxicity of the groundwater plume." The authors of the Vegetable Oil Pilot Project Report

recommended that "organic substrate addition in general and vegetable oil injection specifically be

considered as a future remedial option at this site." The authors of the report have also

recommended that the application of this technology.be limited to "defined contaminant hot spots or

source areas instead of attempting to treat large areas." The report also acknowledges that the

decision to implement the vegetable oil technology in ACP can only be made within the context of

other factors, such as the decreasing levels of contamination .recently observed in ACP due

presumably to recent upgrades in the extraction system.

The USGS capture zone analysis and final report was completed in 2007 (USGS, 2007). The

following is a brief summary of the conclusions from the final report: The capture zone analysis

included the additional hydraulic testing identified in the second Five-Year Review. The purpose of

the USGS report was to determine if the containment system was preventing contaminated

groundwater from migrating offsite. The hydraulic testing and water level measurements collected for

the capture zone analysis indicated that shallow, intermediate, and deep flow zones were present in

the glacial drift aquifer. Groundwater level measurements showed a downward gradient across the

northern portion of the site and an upward gradient across the southern part of the site due to the

effect of the presence of shallow and intermediate clays. Where clay layers are absent a good

vertical connection exists between the different aquifer zones. Where intermediate clays are present,

the intermediate aqUifer flow zone does not exist. The shallow flow zone is hydraulically influenced

by the presence of a clay ridge, near which the potentiometric contours are closely spaced. East and

west of the clay ridge, the water table is relatively flat.

The USGS Report also indicated that shallow flow zone extraction wells AT-8 and AT-9 had

overlapping cones of depression, AT-7 had a more isolated cone of depression, and AT-SA had a

large broad cone of depression. Intermediate flow zone extraction well AT-3A had a broad cone of

depression extending to the intermediate clays that appeared to also draw water up from the deep

030810/P 5-4 eTO 502




zone, while AT-10 had a steep cone of depression, due to the low-permeability zone it was screened

in. Deep flow zone extraction well AT-58 had a broad cone of depression. Capture zone analysis

indicated that the combined contributing areas for shallow zone extraction wells AT-7, AT-8, and AT-9

capture the higher levels of TCE contamination. The contributing area for shallow zone extraction

well AT-5A captures the eastern portion of the highest levels of TCE contamination, however it

appears that not all of the highest-level TCE contamination is captured. The capture analysis for the

combined contributing areas for the intermediate zone extraction wells (AT-3A and AT-10) indicated

that the TCE contamination in the intermediate zone should be captured. However, some uncertainty

is noted for the intermediate extraction well capture zone for AT-3A due to small relief in the

potentiometric surface downgradient of AT-3A, resulting in difficulty delineating the groundwater

divide in this area, as well as because the exact position of the intermediate clay to the north of AT 3A

is unknown. The position of the intermediate clay to the north was better defined through the

installation of monitoring wells MS-551, MS-56S, and MS-561 and through associated borings. The

installation of these additional monitoring wells is also discussed earlier is Section 5 and in Section 7.

Deep zone extraction well AT-58 captures approximately one-third of the TCE contamination

(exceeding 100 parts per billion) in the deep zone that is moving off site. The USGS report also

acknowledged that extraction well AT-3A is probably capturing some water from the deep zone, but

could not quantify the amount.

Well clusters MS-54, MS-55 and MS-56 were installed as recommended in the Second Five-Year Review. Two wells were installed in the shallow zone (MS-54S and MS-56S) and three wells were

installed in the intermediate zone (MS-54I, MS-551, and MS-561). Groundwater quality and elevation

data were collected for all of these new wells in 2005, 2006 and 2007 over a total of four sampling

events. The groundwater quality data for both the shallow zone wells and the intermediate zone wells

show overall decreases in TCE concentration from 2005 to 2007 with the exception of MS-56S. TCE

concentrations in these five wells have decreased between 25 and 50 percent (comparing the 2007

data versus 2005 data) with the exception of MS-56S, which had an overall increase in TCE

concentration of 7 percent. MS-551 and MS-561 had steadily decreasing concentrations from 2005 to

2007, while a significant amount of variability was observed for MS-54S, MS-56S, and MS-541.

Though TCE concentrations in nearly all the wells have decreased significantly from 2005 to 2007,

TCE concentrations observed in MS-54S, MS-54I, MS-56S, and MS-561 have ranged between

130 ~gll and 670 ~gll, 295 ~g/I and 490 ~gll, 93 and 440 ~g/I, and 510 ~g/I and 740 ~g/I, respectively.

Groundwater elevations in the shallow zone at MS-54S and MS-56S have provided additional insight

on the groundwater flow directions in ACP in the area of the groundwater divide. The groundwater

elevation data has been consistent since the installation of these wells. The groundwater elevation

030810/P 5-5 GTO 502




data indicates that MS-54 appears to be located on the east side of the groundwater divide in ACP

(the portion of groundwater flow thought to flow back towards the extraction wells). However, these

water data suggest that MS-56S may be north of the reach of the extraction system and in an area

that migrates toward thl3 river. Groundwater elevations in the intermediate zone at MS-54I, MS-551,

and MS-561 are consistent with water level elevations in nearby intermediate zone wells. The

groundwater elevation clata indicate that intermediate-depth groundwater in the vicinity of MS-551 and

MS-561 is migrating towards the river. However, boring logs from wells from the intermediate zone

did assist in delineating the extent of intermediate clays west of East River Road and in confirming

the gap in the clays in the intermediate zone. Intermediate clays and till (described on the boring log

as stiff sandy clay/clayey sand) are present in the immediate area of MS-551 between 37 and 57 feet

below ground surface (Le., the gap in the intermediate clays extends to the northwest beyond MS-56

to MS-55.

Water level elevation and water quality information from 2005 to 2007 for the MS-54, -55, and -56

series wells assisted in the delineation of capture for the shallow and intermediate aquifer zones. The

following conclusions are preliminary and based on the limited dataset available for the MS-54, -55,

and -56 series wells and these conclusions will continue to be updated in the AMR as more data

becomes available.

The groundwater flow direction at MS-54S indicates that groundwater in this area is being captured,

and the significant decrease of 54 percent in TCE concentrations from 2005 to 2007 at this location

supports this 'preliminary conclusion, though TCE concentrations during this time period, as stated

above, are variable. The slight increase of 7 percent in TCE concentrations from 2005 to 2007 at

MS-56S seem to indicate that some minor bypass is occurring in this area, however, there is a

significant amount of fluctuation in TCE concentrations from 2005 to 2007 for this well. Bypass

occurring in the area of MS-56S may be more related to intermittent extraction system operation

rather than to a constant flux of bypass. Recent analysis of groundwater flow, including that provided

by the USGS (in the report titled Evaluation of the Contributing Area for Recovery Wells at the Naval

Industrial Reserve Ordnance Plan, NIROP, Fridley, Minnesota (2007) (USGS Report)), suggests that

although contamination may bypass the system immediately upgradient of MS-54S, this

contamination is likely captured subsequently by AT-5A.

Groundwater flow directions in the area of MS-541, MS-551, and MS-561 are to the southwest. The

USGS capture zone analysis (conducted in 2001) indicates that the capture zone of AT-3A extends to

the intermediate clays west of the extraction system (including the area that MS-551 and MS-561 were

later installed in), and to the capture zone of AT-10 (south of AT-3A). The consistent decrease in '....."

030810/P 5-6 eTO 502




TCE concentrations from 2005 to 2007 in MS-551 and MS-561 (37 and 31 percent decrease,

respectively), seem to support good capture in. this area, though some uncertainty exists in the

capture zone delineation for AT-3A. MS-541 is located downgradient between intermediate zone

extraction wells AT-3A and AT-10, and though overall there has been a decrease in TCE

concentrations of 24 percent for this well, there is some fluctuation in TCE concentrations from 2005

to 2007. Similar to MS-56S, this fluctuation may be related to intermittent extraction system operation

rather than to a constant flux of contaminated groundwater.

Significant improvements in the groundwater quality in ACP have occurred after the 2001 upgrade to the

extraction system, even though the groundwater extraction system performance has not been consistent

at all times. Maximum TCE concentrations over all aquifer zones in ACP between 1996 and 2001 and

after 2001 were, respectively, 25000 ug/L and 5300 ug/L. Since the 2001 upgrade to the system, the

maximum TCE concentration in ACP has decreased by 79 percent. The significant decrease in TCE

concentrations from 2001 to the present indicates that the groundwater extraction system intercepts the

bulk of contamination migrating towards ACP and the upgrades in 2001 have enhanced the positive

impact on the groundwater quality in ACP.

5.2 OU2 AND OU3 PROGRESS SINCE THE LAST FIVE YEAR REVIEW

For the OU2 and OU3 LUC remedy, no additional actions have been necessary or proposed. There were

no actions recommended in the Second Five Year Review.

030810/P 5-7 eTO 502

6

6.1




6.0 FIVE YEAR REVIEW PROCESS

COMMUNITY NOTIFICATION AND INVOLVEMENT

A pUblic notice that the Third Five-Year Review was being conducted was published on August 8 in the

Sun Focus newspaper, in Fridley, Minnesota.

The Draft Third Five-Year Review Report was provided to EPA and MPCA for review and comment on

April 9, 2008. EPA and MPCA provided comments and proposed revisions by June 12, 2008.

Comments from EPA and MPCA were then addressed and resolved.

The document has been available for pUblic review throughout the process. No public comments were

received. The Navy will sign the document in September 2008. The Navy, EPA, and MPCA may agree

to adjust some of the dates, provided that final signature is attained by October 31, 2008, 5 years after

the signature of the previous Five Yea