USEPA_2001_Record_of_Decision_Area_of_Contamination_57_Devens.pdf

EPA/ROD/R01-01/002

EPA Superfund

Record of Decision:

FORT DEVENS

EPA ID: MA7210025154

OU 09

FORT DEVENS, MA

09/28/2001

RECORD OF DECISION

AREA OF CONTAMINATION 57

DEVENS RESERVE FORCES TRAINING AREA

DEVENS, MASSACHUSETTS

IN ACCORDANCE WITH U.S. ARMY REGULATION 200-2,

THIS DOCUMENT IS INTENDED BY THE U.S. ARMY TO COMPLY WITH THE

NATIONAL ENVIRONMENTAL POLICY ACT OF 1969.

SEPTEMBER 2001

AREA OF CONTAMINATION 57

DEVENS RESERVE FORCES TRAINING AREA

DEVENS, MASSACHUSETTS

SEPTEMBER 2001

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TABLE OF CONTENTS

Section Title Page No.

DECLARATION FOR THE RECORD OF DECISION

1.0 SITE NAME, LOCATION, AND DESCRIPTION

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

2.1 LAND USE AND RESPONSE HISTORY

2.2 ENFORCEMENT HISTORY

3.0 COMMUNITY PARTICIPATION

4.0 SCOPE AND ROLE OF THE RESPONSE ACTION

5.0 SUMMARY OF SITE CHARACTERISTICS

5.1 AOC 57 AREA 2 CONTAMINANT CHARACTERIZATION

5.1.1 Area 2 Soil Characterization

5.1.2 Area 2 Groundwater Characterization

5.1.3 Area 2 Sediment Characterization

5.1.4 Area 2 Surface Water Characterization

5.2 AOC 57 AREA 3 CONTAMINANT CHARACTERIZATION

5.2.1 Area 3 Soil Characterization

5.2.2 Area 3 Groundwater Characterization

5.2.3 Area 3 Sediment Characterization

5.2.4 Area 3 Surface Water Characterization

5.3 CONCEPTUAL SITE MODEL

6.0 CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES

7.0 SUMMARY OF RISK ASSESSMENT

7.1 HUMAN-HEALTH RISK ASSESSMENT

7.2 ECOLOGICAL RISK ASSESSMENT SUMMARY

8.0 PRINCIPAL THREAT WASTES

9.0 GENERAL STATUTORY REQUIREMENTS AND REMEDIAL ACTION OBJECTIVES 26

9.1 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS

9.2 RESPONSE AND REMEDIAL ACTION OBJECTIVES

10.0 DESCRIPTION OF ALTERNATIVES

10.1 DESCRIPTION OF ALTERNATIVES FOR AOC 57 AREA 2

10.1.1 Alternative II-1: No Action

10.1.2 Alternative II-2: Limited Action

10.1.3 Alternative II-3: Excavation (For Possible Future Use) and Institutional Controls . 32

10.1.4 Alternative II-4: Excavation (For Unrestricted Use) And Institutional Controls . . 34

10.2 DESCRIPTION OF ALTERNATIVES FOR AOC 57 AREA 3

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Section Title Page No.

10.2.1 Alternative III-1: No Action

10.2.2 Alternative III-2: Limited Action

10.2.3 Alternative III-3: Excavation (For Unrestricted Use) and Institutional Controls . . 38

10.2.4 Alternative III-2a: Excavation (to Accelerate Groundwater Cleanup) and

Institutional Controls

11.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

11.1 SUMMARY COMPARISON OF AREA 2 ALTERNATIVES

11.1.1 Overall Protection of Human Health and the Environment

11.1.2 Compliance with Applicable or Relevant and Appropriate Requirements

11.1.3 Long-term Effectiveness and Permanence

11.1.4 Reduction of Toxicity, Mobility, or Volume Through Treatment

11.1.6 Implementability

11.1.7 Cost

11.1.8 State Acceptance

11.1.9 Community Acceptance

11.2 SUMMARY COMPARISON OF AREA 3 ALTERNATIVES

11.2.1 Overall Protection of Human Health and the Environment

11.2.2 Compliance with Applicable or Relevant and Appropriate Requirements

11.2.3 Long-term Effectiveness and Permanence

11.2.4 Reduction of Toxicity, Mobility, or Volume Through Treatment

11.2.5 Short-term Effectiveness

11.2.6 Implementability

11.2.7 Cost

11.2.8 State Acceptance

11.2.9 Community Acceptance

12.0 THE SELECTED REMEDY

12.1 DESCRIPTION OF REMEDY FOR AOC 57 AREA 2

12.1.1 Summary of the Rational for Selection of Alternative II-3

12.1.2 Description of Alternative II-3

12.1.3 Summary of Costs for Alternative II-3

12.1.4 Expected Outcome of Alternative II-3

12.2 DESCRIPTION OF REMEDY FOR AOC 57 AREA 3

12.2.1 Summary of the Rational for Selection of Alternative III-2a

12.2.2 Description of Alternative III-2a

12.2.3 Summary of Costs for Alternative III-2a

12.2.4 Expected Outcome of Alternative III-2a

13.0 STATUTORY DETERMINATIONS

13.1 STATUTORY DETERMINATIONS FOR ALTERNATIVE II-3

13.1.1 The Selected Remedy is Protective of Human Health and the Environment iii

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Section Title Page No.

13.1.2 The Selected Remedy Attains Applicable or Relevant and Appropriate Requirements

13.1.3 The Selected Remedial Action is Cost-Effective

13.1.4 The Selected Remedy Utilizes Permanent Solutions and Alternative Treatment or

Resource Recovery Technologies to the Maximum Extent Practicable

13.1.5 The Selected Remedy Does Not Satisfy the Preference for Treatment as a

Principal Element

13.1.6 Five-Year Review Requirements

13.2 STATUTORY DETERMINATIONS FOR ALTERNATIVE III-2A

13.2.1 The Selected Remedy is Protective of Human Health and the Environment

13.2.2 The Selected Remedy Attains Applicable or Relevant and Appropriate

Requirements

13.2.3 The Selected Remedial Action is Cost-Effective

13.2.4 The Selected Remedy Utilizes Permanent Solutions and Alternative Treatment or

Resource Recovery Technologies to the Maximum Extent Practicable

13.2.5 The Selected Remedy Satisfies the Preference for Treatment as a Principal

Element

13.2.6 Five-Year Review Requirements

14.0 DOCUMENTATION OF SIGNIFICANT CHANGES

15.0 STATE ROLE

GLOSSARY OF ACRONYMS AND ABBREVIATIONS

REFERENCES

APPENDICES

APPENDIX A - FIGURES

APPENDIX B - TABLES

APPENDIX C - RESPONSIVENESS SUMMARY

APPENDIX D - ADMINISTRATIVE RECORD INDEX

APPENDIX E - DECLARATION OF STATE CONCURRENCE

APPENDIX F - GLOSSARY OF ACRONYMS AND ABBREVIATIONS

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LIST OF FIGURES

Figures No. Title

1 Location of AOC 57

2 Location of Areas 1, 2, and 3

3 Areas 1, 2, and 3 Site Map

4 Area 2 Monitoring Well Locations

5 Area 3 Monitoring Well Locations

6 Conceptual site Model

7 Area 2 Soil Areas Exceeding PRGs

8 Area 3 Soil Area Exceeding Unrestricted Use PRGs

9 Alternative III-2a Estimated Soil Excavation Area

10 Alternative II-3 Soil Excavation Area vi

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LIST OF TABLES

Table No. Title

1 Summary of AOC 57 Areas 2 and 3 Risk Assessment Scenarios

2 Quantitative Human-Health Risk Summary

3 Comparison of Area 2 Human-health Risk Estimates To USEPA Criteria

4 Comparison of Area 3 Human-health Risk Estimates To USEPA Criteria

5 Area 2 Primary Risk Contributors

6 Area 3 Primary Risk Contributors

7 AOC 57 Soil Preliminary Remediation Goals

8 AOC 57 Groundwater Preliminary Remediation Goals

9 Summary of ARARs for AOC 57 Area 2

10 Summary of ARARs for AOC 57 Area 3

11 Cost Summary for Alternative II-3: Excavation (For Possible Future Use) and Institutional Controls

12 AOC 57 Cleanup Levels for Contaminants of Concern

13 Cost Summary for Alternative III-2a: Excavation (to Accelerate Groundwater Cleanup) and Institutional Controls

14 Synopsis of Federal and State Location-specific ARARs for Alternative II-3

15 Synopsis of Federal and State Chemical-specific ARARs for Alternative II-3

16 Synopsis of Federal and State Action-specific ARARs for Alternative II-3

17 Synopsis of Federal and State Location-specific ARARs for Alternative III-2a

18 Synopsis of Federal and State Chemical-specific ARARs for Alternative III-2a

19 Synopsis of Federal and State Action-specific ARARs for Alternative III-2a

DECLARATION

AOC 57 RECORD OF DECISION

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D-1

DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION

Area of Contamination 57 Devens Reserve Forces Training Area Devens, Massachusetts

CERCLIS ID MA7210025154

STATEMENT OF PURPOSE AND BASIS

This decision document presents the U. S. Army Devens Reserve Forces Training Area (RFTA) (formerly Fort Devens), Devens, Massachusetts. It was developed in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), 42 USC §§ 9601 et seq., as amended by the Superfund Amendments and Reauthorization Act of 1986, and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) 40 CFR Part 300, et seq., as amended. The Devens Base Realignment and Closure (BRAC) Environmental Coordinator and the Director of the Office of Site Remediation and Restoration, U.S. Environmental Protection Agency (USEPA) Region 1, have been delegated the authority to approve this Record of Decision. AOC 57 comprises three subareas:

Area 1, Area 2, and Area 3.

This decision is based on the Administrative Record that has been developed in accordance with Section 113(k) of CERCLA. The Administrative Record is available for public review at the Devens BRAC Environmental Office, Devens, Massachusetts, and at the Ayer Town Hall, Main Street, Ayer, Massachusetts. The Administrative Record Index (Appendix D of this Record of Decision) identifies each of the items considered during selection of the remedial action.

STATE CONCURRENCE

The Commonwealth of Massachusetts concurs with the selected remedies. Appendix E of this Record of Decision contains a copy of the Declaration of State Concurrence.

ASSESSMENT OF SITE

The response actions selected in this Record of Decision are necessary to protect public health or welfare or environment from actual or threatened releases of hazardous substances to the environment.

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DESCRIPTION OF THE SELECTED REMEDY

The selected remedies for AOC 57 are:

C Area 1- No Further Action C Area 2 - Alternative II-3: Excavation (For Possible Future Use) and Institutional Controls C Area 3 - Alternative III-2a; Excavation (to Accelerate Groundwater Cleanup) and Institutional

Controls

Area 1

Area 1 is a storm-drain outfall and drainage ditch that receives precipitation runoff from paved areas around Building 3713. The discharge to the storm drainage ditch eventually flows to Cold Spring Brook. An estimated 50 to 100-gallon spill of No. 4 fuel oil was discharged through the Area 1 outfall in 1977. Approximately 3,000 gallons of mixed oil and water were recovered through use of containment dikes and absorbent booms in 1977, and approximately 25 cubic yards (cy) of petroleum contaminated soil were removed in 1997. Review of available data indicates that contamination associated with the fuel oil spill has been removed, and a risk assessment indicates that there are no unacceptable risks for unrestricted use.

The selected remedy at Area 1 is No Further Action.

Area 2

At Area 2 the selected remedy is Alternative II-3: Excavation (For Possible Future Use) and Institutional Controls. This remedy is a comprehensive approach that addresses all current and potential future risks caused by soil and groundwater contamination. Area 2 is located adjacent to a former vehicle storage yard associated with motor repair shops at the former Fort Devens. Although the 1977 fuel oil spill at Building 3713 primarily affected Area 1, Area 2 was investigated because a portion of the spill was reported to have flowed to Area 2 via an eroded drainage ditch. Data gathered during the remedial investigation (RI) as well as preceding investigations suggests that Area 2 contamination is the result of the historical disposal of vehicle maintenance wastes along the break in slope between an upland and flood plain area. Removal of approximately 1,300 cy of contaminated soil from Area 2 in 1994 addressed what was considered a principal threat at Area 2. There are no principal threat wastes remaining at AOC 57 Area 2.

Subsequent investigations and risk assessment indicate human-health risks within or below the USEPA target cancer-risk range and noncancer threshold under current land use conditions, but indicate potential risks to construction workers exceeding the USEPA target risk threshold from exposure to soil under possible future use conditions. Further, under hypothetical unrestricted (i.e., residential) use conditions the risk assessment indicates potential risks to residents exceeding the USEPA target cancer-risk range and noncancer threshold for exposure to flood plain soil and groundwater.

The key components of the selected remedy at AOC 57 Area 2 consist of the following:

C Soil Excavation and treatment/disposal at an off-site treatment, storage, or disposal facility C Wetlands Protection C Institutional Controls

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D-3

B Existing zoning that prohibits residential use of Area 2 property and proposed deed restrictions that prohibit potable use of Area 2 groundwater and residential use of flood plain property

• Environmental Monitoring B Long-term groundwater monitoring B Long-term surface water monitoring

• Institutional Control Inspections

• Five-year Site Reviews

This remedy relies on excavation of soil exceeding cleanup levels to protect future use construction workers, and institutional controls in the form existing zoning and proposed deed restrictions to prevent potable use of groundwater. If future land use at AOC 57 is inconsistent with these institutional controls, then the site exposure scenarios for human health and the environment would be re-evaluated to assess whether this response action remains appropriate. To the extent practical, remedial activities will be performed with minimal alteration or disturbance of wetlands, and disturbed areas will be restored. Long-term environmental monitoring will be implemented to assess the success of restoration activities, maintenance of surface water quality, and to monitor for attainment of groundwater cleanup levels.

Area 3

At Area 3 the selected remedy is Alternative III-2a: Excavation (to Accelerate Groundwater Cleanup) and Institutional Controls. This remedy is a comprehensive approach that addresses all current and potential future risks caused by soil and groundwater contamination. Area 3 is located adjacent to a former vehicle storage yard associated with motor repair shops at the former Fort Devens. Data gathered during the RI, as well as preceding investigations, suggest that Area 3 contamination is the result of the historical disposal of vehicle maintenance wastes. Removal of approximately 1,800 cy of contaminated soil from Area 3 in 1999 addressed what was considered a principal threat at Area 3. There are no principal threat wastes remaining at AOC 57 Area 3.

Subsequent investigations and risk assessments indicate human-health risks within or below the USEPA target cancer risk range and noncancer threshold under current land use conditions, but indicate potential risks to commercial/industrial workers exceeding the USEPA target risk range from exposure to groundwater under possible future use conditions. Further, under hypothetical unrestricted (i.e., residential) use conditions, the risk assessment indicates potential risks to residents exceeding the USEPA target cancer risk range and noncancer threshold for exposure to soil and groundwater.

The key components of the selected remedy at AOC 57 Area 3 consist of the following:

• Soil Excavation and treatment/disposal at an off-site treatment, storage, or disposal facility

• Wetlands Protection

• Institutional Controls o Existing zoning that prohibits residential use of Area 3 property and proposed deed restrictions that prohibit potable use of Area 3 groundwater and residential use of flood plain property

• Environmental Monitoring o Long-term groundwater monitoring

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D-4 o Long-term surface water monitoring

• Institutional Control Inspections

• Five-year Site Reviews

This remedy relies on excavation of soil to accelerate restoration of aerobic (i.e., nonreducing) conditions to groundwater and reduce the release of naturally occurring arsenic from soil. Also included are institutional controls in the form of existing zoning and proposed deed restrictions to prohibit potable use of groundwater in both upland or flood plain areas. If future land use at AOC 57 is inconsistent with these institutional controls, then the site exposure scenarios for human health and the environment would be re-evaluated to assess whether this response action remains appropriate. Long-term environmental monitoring will be implemented to assess the success of restoration activities, maintenance of surface water quality, and to monitor for attainment of groundwater cleanup levels.

STATUTORY DETERMINATIONS

Area 1

The selected remedy for Area 1 is protective of human health and the environment, attains federal and state environmental and facility siting requirements that are applicable to the remedial action, is cost effective, and utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable.

Because the No Action remedy at Area 1 will not result in hazardous substances, pollutants, or contaminants remaining on site above concentrations that allow for unrestricted exposure, a five-year review will not be required for this portion of the site.

Area 2

The selected remedy for Area 2 is protective of human health and the environment, attains federal and state environmental and facility siting requirements that are applicable to the remedial action, is cost effective, and utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable. To the extent that the treatment, storage, or disposal facility that receives the soil excavated from Area 2 provides treatment, the selected remedy will satisfy the statutory preference for treatment as a principal element.

Removal/excavation of soil from Area 2 will reduce contaminant mobility in that environment and eliminate risk to future construction worker receptors.

Because the remedy for Area 2 will result in hazardous substances, pollutants, or contaminants remaining on site above concentrations that allow for unrestricted exposure and unlimited use, a statutory review will be performed within five years of initiation of remedial action to ensure that the remedy remains protective of human health and the environment. Subsequent five-year reviews will be performed as long as hazardous substances, pollutants, or contaminants remain on-site above concentrations that allow for unrestricted exposure and unlimited use.

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D-5

Area 3

The selected remedy for Area 3 is protective of human health and the environment, attains federal and state environmental and facility siting requirements that are applicable to the remedial action, is cost effective, and utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable. To the extent that the treatment, storage, or disposal facility that receives the soil excavated from Area 3 provides treatment, the selected remedy will satisfy the statutory preference for treatment as a principal element.

Previous removal actions have reduced the mobility of site contaminants.

Because the remedy for Area 3 will result in hazardous substances, pollutants, or contaminants remaining on site above concentrations that allow for unrestricted exposure and unlimited use, a statutory review will be performed within five years of initiation of remedial action to ensure that the remedy remains protective of human health and the environment. Subsequent five-year reviews will be performed as long as hazardous substances, pollutants, or contaminants remain on-site above concentrations that allow for unrestricted exposure and unlimited use.

DATA CERTIFICATION CHECKLIST

The following information is contained in the Decision Summary section of this Record of Decision. Additional information can be found in the Administrative Record file.

• Chemicals of concern and their respective concentrations

• Baseline risk represented by the chemicals of concern

• Cleanup levels established for chemicals of concern and the basis for those levels

• How source materials constituting principal threats are addressed

• Current and reasonably anticipated future land use assumptions and the current and potential future beneficial uses of groundwater used in the baseline risk assessment

• Potential land and groundwater use that will be available at the site as a result of the selected remedy

• Estimated capital, annual operation and maintenance, and total present worth costs; discount rate; and the number of years over which the remedy cost estimates are projected

• Key factors that led to selection of the remedy

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D-6

AUTHORIZING SIGNATURES

The foregoing represents the selection of a remedial action by the U.S. Department of the Army and the U.S.

Environmental Protection Agency, with the concurrence of the Commonwealth of Massachusetts Department of Environmental Protection.

Concur and recommend for immediate implementation:

U.S. DEPARTMENT OF THE ARMY

DECISION SUMMARY

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DECISION SUMMARY

1.0 SITE NAME, LOCATION, AND DESCRIPTION

This Record of Decision addresses past releases to soil and groundwater at Area of Contamination (AOC) 57 at Devens Reserve Forces Training Area (RFTA), Devens Massachusetts. The Devens RFTA, formerly Fort Devens, is located in the Towns of Ayer and Shirley (Middlesex County) and Harvard and Lancaster (Worcester County), approximately 35 miles northwest of Boston, Massachusetts. A Federal Facilities Agreement between the U.S. Department of the Army and the U.S. Environmental Protection Agency (USEPA) establishes the Army as the lead agency for developing, implementing, and monitoring response actions at Devens RFTA in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). Fort Devens is identified by the CERCLIS ID number MA7210025154.

AOC 57 is located between Barnum Road and Cold Spring Brook on the northeast side of what was formerly the Main Post of Fort Devens, in the town of Harvard, Massachusetts (Figure 1). It is in an area of the former Fort Devens that was used primarily for the storage and maintenance of military vehicles. AOC 57 was first investigated as Study Area (SA) 57 - Building 3713 Fuel Oil Spill.

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

This section provides a brief description of the historical land use at Devens RFTA, investigative and response history at AOC 57, and enforcement history.

2.1 LAND USE AND RESPONSE HISTORY

Fort Devens was established in 1917 as Camp Devens, a temporary training camp for soldiers from the New England area. In 1931, the camp became a permanent installation and was renamed Fort Devens. Throughout its history, Fort Devens served as a training and induction center for military personnel, and as a unit mobilization and demobilization site. All or portions of this function occurred during World Wars I and II, the Korean and Vietnam conflicts, and operations Desert Shield and Desert Storm. During World War II, more than 614,000 inductees were processed, and Fort Devens reached a peak population of 65,000.

The primary mission of Fort Devens was to command, train, and provide logistical support for nondivisional troop units and to support and execute Base Realignment and Closure (BRAC) activities. The installation also supported the Army Readiness Region and National Guard units in the New England area. Fort Devens was identified for cessation of operations and closure under Public Law 101-510, the Defense Base Realignment and Closure Act of 1990, and was officially closed in September 1996. Portions of the property formerly occupied by Fort Devens were retained by the Army for reserve forces training and renamed the Devens RFTA. Areas not retained as part of the Devens RFTA were, or are in the process of being, transferred to new owners for reuse and redevelopment.

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AOC 57 is located on the south side of Barnum Road in an area of the former Fort Devens that was used primarily for the storage and maintenance of military vehicles. In addition, areas north of Barnum Road have historically been, and continue to be, used as rail yards and for freight handling and storage. AOC 57 consists of three subareas (Area 1, Area 2, and Area 3) located south to southeast of Building 3713 and former buildings 3756, 3757 and 3758 (Figure 2). These subareas historically received stormwater runoff and wastes from vehicle maintenance at former vehicle storage yards associated with Building 3713 and former buildings 3757 and 3758. Former Building 3756 was a mess hall that was converted to a general storehouse. The vehicle storage yards were abandoned in 1998, and the pavement and fencing were removed. The former storage yards are now soil and grass-covered areas.

AOC 57 Areas 2 and 3 are located within Lease Parcel A6a that the Army plans to transfer to the Massachusetts Government Land Bank. This Record of Decision defines each area as an upland area (elevations greater than 228 feet (ft.) mean sea level [msl]) that slopes downward to a 100-year flood plain (elevations less than 228 ft. msl). This characterization more accurately describes AOC 57 than the Feasibility Study and Proposed Plan that used the term "wetland" to describe all areas at AOC 57 with an elevation less than 228 ft. msl. In fact, based on a 1993 wetland delineation, wetland conditions at Area 2 extend only up to approximately 222 ft. msl. This change in definition has not affected the selection of remedial actions at Areas 1, 2, or 3.

The upland area at AOC 57 is forested with trees and scrub brush. At Area 2 the flood plain boundary is located approximately 300 ft. from Cold Spring Brook, and at Area 3 the flood plain boundary is located approximately 400 ft. from Cold Spring Brook. The flood plain area is densely vegetated with brush and contains small areas of standing water. Based on a 1993 wetlands delineation, proposed remedial activities at Area 2 may extend into the Cold Spring Brook bordering vegetated wetland. The 1993 wetlands delineation did not include Area 3, but proposed remedial activities at Area 3 may also extend into the Cold Spring Brook bordering vegetated wetland. A portion of Area 1 is located outside of Lease Parcel A6a and outside of the 100-year flood plain (i.e., at an elevation greater than 228 ft. msl).

Lease Parcel A6a is located within 500 ft. of the Devens public water supply line that serves Barnum Road.

The parcel is also located approximately 2,500 ft. southwest of the Devens Grove Pond well field and 3,000

ft. southwest of the Town of Ayer water supply wells on the south shore of Grove Pond. It is outside the Zone II for both the Devens Grove Pond Wellfield and the Ayer Grove Pond wells (see Figure 2).

Groundwater elevation data indicate that the groundwater flow direction at AOC 57 is to the southeast and away from Grove Pond and the water supply wells.

According to Exhibit A of the Devens Zoning By-laws, Zoning District Parcel Maps (Vanasse Hangen Brustlin, 1994a), and the Devens Re-use Plan (Vanasse Hangen Brustlin, 1994b), land on the southeast side of Barnum Road is included either in Zoning District Parcel 17, which is zoned for Rail, Industrial, and Trade Related use, or in the Open Space and Recreation Zoning District. The narrative description accompanying the Zoning District Parcel Maps indicates that the boundary between these zones is the flood plain line. As shown on Figures 2 and 3, the 100-year flood plain crosses Lease Parcel A6a and bisects AOC 57 Areas 2 and 3. Therefore, Rail, Industrial, and Trade Related zoning applies to upland regions at AOC 57, while Open Space and Recreation zoning applies to flood plain regions.

Area 1. Area 1 consists of a stormwater outfall area and drainage ditch (Storm Drainage System 6 of the Storm Sewer System Evaluation [AREE 70] Report [ADL, 1994]) that receives precipitation collected from

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paved areas around Building 3713 (see Figure 3). The discharge to the storm drainage ditch eventually flows to Cold Spring Brook The following items summarize the history of Area 1 at AOC 57.

1977. On February 13, 1977, Fort Devens personnel at Building 3713 noticed No. 4 fuel oil flowing from an overfilled 30,000 gallon underground storage tank (UST) into a nearby storm drain (Biang et al., 1992; DFAE, 1977). The storm drain discharged the spilled No. 4 fuel oil to a drainage ditch at the Area 1 outfall. The released oil flowed down the ditch to Cold Spring Brook. There was no evidence on February 13 and 14 of more than 50 to 100 gallons of fuel oil in the potentially affected water courses. Nevertheless, containment dikes and absorbent booms were set up across Cold Spring Brook adjacent to Area 2, and approximately 3,000 gallons of mixed oil and water were recovered (DFAE,1977).

1992. Area 1 at AOC 57, then SA 57, was investigated as part of the Site Investigation (SI) of Groups 2 and 7 Historic Gas Stations (ABB-ES, 1995a). Surface soil, surface water, and sediment samples were collected, and analysis identified polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) in surface soil. A Preliminary Risk Evaluation (PRE) indicated no unacceptable risk for presumed commercial/industrial site reuse. The Army recommended further investigation of Area 1 as part of the installation-wide AREE 70 storm sewer study.

1994. The AREE 70 evaluation included AOC 57 Area 1 (Storm Drain System 6) (ADL, 1994). Analyses of surface water and sediment samples indicated elevated levels of arsenic, chromium, and lead in sediment and arsenic and lead in surface water. Semivolatile organic compounds (SVOCs) were also detected at a maximum total SVOC concentration of 59.8 micrograms per gram (µg/g). Results of the sampling were incorporated into the Lower Cold Spring Brook SI ecological PRE.

1994. The Lower Cold Spring Brook SI included sampling results from the AREE 70 report in its assessment of potential risks (ABB-ES, 1995b). The Lower Cold Spring Brook SI produced no evidence that surface water contaminants posed risks to aquatic receptors. Furthermore, no ecological risks were identified from exposure to contaminated media in several storm drain systems, including Storm Drain System 6 (AOC 57 Area 1). No further study was recommended for Area 1.

1997. Although there were no unacceptable risks, the Army performed a soil removal action at the Area 1 outfall area in response to newly promulgated Massachusetts Contingency Plan (MCP) standards to address soil contamination resulting from releases of petroleum (Weston, 1998). An approximate 22- by 22.5- ft. area was excavated to maximum depth of 3 ft. In all, approximately 25 cubic yards (cy) of contaminated soil were removed. Although some PAH contaminants at the limit of the excavation exceeded the MCP S-1/GW-1 standards, statistical review of the data indicated that remaining contamination was consistent with that expected from asphalt paved and traffic areas along Barnum Road. It was further concluded based on data review that fuel oil contamination had been successfully removed. The removal action report recommended no further action at Area 1 with the intent that the decision be formalized in the AOC 57 Record of Decision (Weston, 1998).

2000. An assessment of risks was performed as part of the AOC 57 Remedial Investigation (RI) to demonstrate Area 1 does not pose unacceptable risk for future unrestricted land use. The assessment indicates that there are no unacceptable risks for future unrestricted land use (Refer to Appendix N-1 of the RI report [HLA, 2000a]), and the RI report recommended no further action at AOC 57 Area l.

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Area 2. Area 2 is located approximately 700 ft. northeast of Area 1, and adjacent to a former vehicle storage yard associated with the motor repair shops located in former Buildings 3757 and 3758 (see Figure 3). The nearby former Building 3756 served as a mess hall and was later converted to a general storehouse. Area 2 was originally thought to have been contaminated by the Area 1 No. 4 fuel oil spill; however, area grading was such that overland flow to Area 2 would not have been possible. When initially investigated, this Area 2 consisted of an eroded drainage ditch created by periodic rainfall runoff from vehicle storage yards associated with Buildings 3757 and 3758. The area has since been regraded (following a soil removal action) and a permanent drainage swale has been installed. Runoff drains into the swale and discharges east to Cold Spring Brook. Portions of Area 2 are within the Cold Spring Brook 100-year flood plain (see Figures 2 and 3). Data gathered during the RI as well as preceding investigations suggests that Area 2 contamination is the result of the historical disposal of vehicle maintenance related wastes. Contaminant distributions indicate that the disposal occurred along the break in slope above the flood plain. The following items summarize the history of Area 2 at AOC 57.

1992. The drainage ditch at Area 2 was investigated as part of the SI for Groups 2 and 7 Historic Gas Stations (ABB-ES, I995a). Naphthalene and TPH were detected in surface soil. Fingerprint analysis of soil from Area 2 indicated that contaminants in the soil were most likely derived from lubricating oil, possibly vehicle crankcase oil, and not the 1977 release of No. 4 fuel oil. Results of human-health and ecological PREs indicated that the chemical hazards at Area 2 were not significant.

1994. The Army performed a soil removal action at Area 2 in 1994 in response to newly promulgated MCP standards (OHM, 1996). Based on available data and a cleanup level for TPH of 500 milligrams per kilogram (mg/kg), it was estimated that 350 tons of soil would need excavation. The removal action

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concluded that there was not a significant risk to ecological receptors. The RI report recommended that the Army perform a FS to evaluate alternatives to address risks to human health.

2000. The Army prepared a FS report to evaluate candidate remedial alternatives for control of risk from exposure to remaining contaminants at AOC 57 (Harding ESE, 2000).

2000. During December 2000, the Army collected additional soil samples at Area 2 from four locations at the southern end of the former excavation to further characterize the distribution of extractable petroleum hydrocarbons (EPH) (Harding ESE, 2001). Sampling locations were selected to correspond to historical locations with the highest EPH concentrations. EPH were detected in the December 2000 samples at concentrations that would not pose unacceptable risk to human health.

Area 3. Area 3 is located approximately 600 ft. to the northeast of Area 2, south of former vehicle maintenance motor pools. Portions of Area 3 are within the Cold Spring Brook 100-year flood plain (see Figure 3). The site is characterized by a historic garage and vehicle waste disposal area. The following items summarize the history of Area 3 at AOC 57.

1995. Four test-pits were excavated east of Area 2 where historical photos indicated soil staining. Sample analysis showed the presence of TPH and chlorinated VOCs. The area was designated AOC 57 Area 3.

1996 through 1998. RI field investigations were performed to better characterize the nature and extent of contamination (HLA, 2000a). RI activities included collection of 40 soil samples from eight test pits; 87 soil samples from 20 TerraProbe points, six soil borings, and one monitoring well boring; collecting five

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shows that the MCP S-2/GW-3 cleanup goals were met in sidewall samples except at the southern end of the excavation where exceedance of the volatile petroleum hydrocarbon (VPH), EPH, Aroclor-1260, and dieldrin goals occurred. Comparison to the risk-based cleanup goals showed exceedance (4.3 µg/g vs. 2µg/g) of the Aroclor-1260 goal. In total, 1,860 cy of material, comprising the majority of Area 3 soil contamination, were removed (HLA, 2000a).

2000. The Army prepared a FS report to evaluate candidate remedial alternatives for control of risk from exposure to remaining contaminants at AOC 57 (Harding ESE, 2000).

2000. In response to regulatory agency concerns, the Army installed two small–diameter groundwater screening points at Area 3 to further characterize the presence of chlorinated compounds in groundwater (HLA, 2000b; Harding ESE, 2000). Each point consisted of nominal ½-inch inside diameter pipe with a five-ft.

vertically slotted screen. The points were advanced and sampled at 10-ft. intervals beginning at the water table. Point 57N-00-01X was advanced to 58 ft. below ground surface (bgs) downgradient of the source area, and point 57N-00-02X was advanced to 79 ft. bgs upgradient of the source area. Groundwater samples were analyzed at an on-site laboratory for tetrachloroethene (PCE), trichloroethene (TCE), dichloroethene (DCE), 1,2-dichlorobenzene (1,2-DCB), and 1,4-dichlorobenzene (1,4-DCB). Massachusetts Department of Environmental Protection (MADEP) representatives collected split samples for off-site analysis of VOCs by USEPA Method 8260B.

Six samples were collected for on-site screening from the downgradient location 57N-00-01X. On-site analysis did not detect target compounds in any of these samples.

Seven samples were collected for on-site screening from 57N-00-02X located approximately 25 ft. upgradient of the previously excavated Area 3 source area. The only detection of PCE, 1 microgram per Liter (µg/L), was from the sample collected from 34 to 39 ft. bgs. TCE was detected at 12.4 µg/L in the sample collected at 54 to 59 ft. bgs. No other target compounds were detected. Based upon the depth of these detections and their upgradient location, these contaminants are not attributed to the Area 3 source area.

2001. On April 3, 2001, USEPA and MADEP collected groundwater samples from six Area 3 monitoring wells (57M-95-03X, 57M-96-09X, 57M-96-10X, 57M-96-11X, 57M-96-12X, and 57M-96-13X) to assess groundwater quality. The samples were analyzed for Target Analyte List VOCs and the inorganics arsenic, barium, cadmium, and zinc. The analytical results showed one exceedance of drinking water standards:

arsenic at 80 to 91 µg/L in the sample from 57M-96-11X.

2.2 ENFORCEMENT HISTORY

On December 21, 1989, Fort Devens was placed on the National Priorities List (NPL) under CERCLA as amended by the Superfund Amendments and Reauthorization Act (SARA) to evaluate and implement response actions to cleanup past releases of hazardous substances, pollutants, and contaminants. A Federal Facilities Agreement to establish a procedural framework for ensuring that appropriate response actions are implemented at Fort Devens was developed and signed by the Army and the USEPA Region I on May 13, 1991, and finalized on November 15, 1991. AOC 57 is considered a sub-site to the entire installation.

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In 1995, the Army initiated a RI for AOC 57. The RI report was issued in June 2000. The purpose of the RI was to determine the nature and extent of contamination at the AOC, assess human-health and ecological risks, and provide a basis for conducting a FS.

An FS that evaluates remedial action alternatives for cleanup of groundwater was issued in November 2000.

The FS identifies and screens remedial alternatives and provides a detailed analysis of seven of these remedial alternatives to allow decision-makers to select a remedy for cleanup of AOC 57.

The proposed plan detailing the Army's preferred remedial alternatives for Areas 2 and 3 at AOC 57 was issued in February 2001 for public comment. Technical comments presented during the public comment period are included in the Administrative Record. Appendix C of this Record of Decision, the Responsiveness Summary, contains a summary of these comments and the Army's responses, and describes how these comments affected the remedy selection.

3.0 COMMUNITY PARTICIPATION

The Army has held regular and frequent informational meetings, issued fact sheets and press releases, and held public meetings to keep the community and other interested parties informed of activities at AOC 57.

Community interest in AOC 57 was low throughout this process until issuance of the Proposed Plan. At that time, several community members and local groups expressed strong concerns about the Army's preferred alternatives and time frames to achieve groundwater cleanup goals.

In February 1992, the Army released, following public review, a community relations plan that outlined a program to address community concerns and keep citizens informed about and involved in remedial activities at Fort Devens. As part of this plan, the Army established a Technical Review Committee (TRC) in early 1992. The TRC, as required by SARA Section 211 and Army Regulation 200-1, included representatives from USEPA, U.S. Army Environmental Center, Devens RFTA, MADEP, local officials, and the community. Until January 1994, when it was replaced by the Restoration Advisory Board (RAB), the committee generally met quarterly to review and provide technical comments on schedules, work plans, work products, and proposed activities for the SAs and AOCs at Devens RFTA. The AREE, SI, RI, and FS reports, Proposed Plan, and other related support documents were all submitted to the TRC or RAB for their review and comment.

The Army, as part of its commitment to involve the affected communities, forms a RAB when an installation closure involves transfer of property to the community. The Fort Devens RAB was formed in February 1994 to add members of the Citizen's Advisory Committee (CAC) to the TRC. The CAC had been established previously to address Massachusetts Environmental Policy Act/Environmental Assessment issues concerning the reuse of property at Devens RFTA. The RAB consists of 28 members (15 original TRC members plus 13 new members) who are representatives from the Army, USEPA Region I, MADEP, local governments and citizens of the local communities. It meets monthly and provides advice to the installation and regulatory agencies on the Devens RFTA cleanup programs. Specific responsibilities include: addressing cleanup issues such as land use and cleanup goals, reviewing plans and documents, identifying proposed requirements and priorities, and conducting regular meetings that are open to the public.

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On February 23, 2001, the Army issued the Proposed Plan, to provide the public with a brief explanation of the Army's proposal for remedial action at AOC 57. The Proposed Plan also described the opportunities for public participation and provided details on the upcoming public comment period and public meeting.

On February 23, 2001, the Army published a public notice announcing the Proposed Plan, the date for a public informational meeting, and the start and end dates of a 31-day public comment period in the Leominster Fitchburg Sentinel & Enterprise, Worcester Telegram, Harvard Post, and papers of the Nashoba Publishing Company (Groton Landmark, Harvard Hillside, Pepperell Free Press, The Public Spirit, Shirley Oracle, and Townsend Times). The Public Notice was published in the Lowell Sun on February 26, 2001. The public notices were republished by the Leominster Fitchburg Sentinel & Enterprise, Lowell Sun, Worcester Telegram and Harvard Post on March 5, 2001, and by Nashoba Publishing Company on March 7, 2001.

Notice announcing a 30-day extension of the public comment was published in the Lowell Sun on March 28, 2001, Leominster Fitchburg Sentinel & Enterprise on March 28, 2001, Worcester Telegram on March 28, 2001, Harvard Post on March 30, 2001, and in the Groton Landmark, Harvard Hillside, Pepperell Free Press, The Public Spirit, Shirley Oracle, and Townsend Times on March 30, 2001. The Army also made the Proposed Plan available to the public at the public information repositories at the Ayer Public Library, the Hazen Memorial Library in Shirley, the Harvard Public Library, and the Lancaster Public Library, or by request from the Devens BRAC Environmental Office.

From February 23 through April 25, 2001, the Army held a 61-day public comment period to accept public comments on the Proposed Plan. On March 8, 2001, the Army held an informal public information meeting at Devens RFTA to present the Army's Proposed Plan to the public and to provide the opportunity for open discussion concerning the Proposed Plan. The Army also accepted formal verbal or written comments from the public during a public hearing held as part of the meeting. A transcript of this hearing, formal public comments, and the Army's response to comments are included in the attached Responsiveness Summary (see Appendix C).

All supporting documentation for the decision regarding AOC 57 is contained in the Administrative Record for review. The Administrative Record is a collection of all the documents considered by the Army in choosing the plan of action for AOC 57. On February 23, 2001, the Army made the Administrative Record available for public review at the Devens BRAC Environmental Office and at the Ayer Town Hall, Ayer, Massachusetts. An index to the Administrative Record is available at the USEPA Records Center, 90 Canal Street, Boston, Massachusetts and is provided as Appendix D of this Record of Decision.

4.0 SCOPE AND ROLE OF THE RESPONSE ACTION

This Record of Decision documents the selection of remedial actions proposed for control of site risks at Areas 2 and 3 of AOC 57. In addition, it formalizes the recommendations for No Further Action at Area 1 proposed in the Removal Action Report for Study Area 57, Area 1, Storm Drain System No. 6 Outfall (Weston, 1998) and in the final RI report (HLA, 2000a). There is no identified risk to human health or the environment at Area 1, and no further remedial action is required under CERCLA. Further, because the

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limited nature of remaining contamination at Area 1 is typical of contamination at stormwater outfalls in Massachusetts, it is exempt from MCP requirements.

Implementation of Alternative II-3 (Excavation [For Possible Future Use] and Institutional Controls) at Area 2 will protect possible future use construction workers from the threat of exposure to contaminated flood plain soil by removal of soil exceeding cleanup criteria. The presence of flood plain and wetland conditions and existing zoning currently prevent residential use of the area and potential residential exposure to contaminated soil and groundwater. In addition, Alternative II-3 will protect potential future area residents from the threat of direct contact exposure to flood plain soil and exposure to contaminated groundwater by establishing institutional controls that prohibit residential use of flood plain property and potable use of groundwater.

Implementation of Alternative III-2a at Area 3 will protect possible future commercial workers and unrestricted use residents from exposure to groundwater and protect future unrestricted use residents from exposure to contaminated flood-plain soil by establishing institutional controls that prohibit potable use of Area 3 groundwater and residential use of flood plain property. In addition, groundwater cleanup will be accelerated by excavation of soil containing contaminants that cause reducing conditions which result in release of naturally occurring arsenic from soil to groundwater. The presence of flood plain and wetland conditions and existing zoning currently prevent residential use of the area and potential residential exposure to contaminated soil. To protect future unrestricted use residents from exposure to contaminated flood-plain soil and groundwater in the event of future property transfer, the Army would include deed covenants to prohibit residential use of flood plain property and potable use of groundwater in flood plain.

Implementation of the selected remedial actions at Areas 2 and 3 will address all remaining identified threats at AOC 57.

5.0 SUMMARY OF SITE CHARACTERISTICS

The following subsections summarize the nature and distribution of contamination presented in the AOC 57 RI report (HLA, 2000). The discussion of soil contamination represents conditions following soil removal actions performed at Areas 2 and 3 in 1994 and 1999, respectively.

5.1 AOC 57 AREA 2 CONTAMINANT CHARACTERIZATION

Contaminated media at AOC 57 Area 2 include surface and subsurface soil, groundwater, sediment, and surface water. The nature and extent of contamination is described in detail in the final RI report and is summarized in the FS report and in the following subsections.

5.1.1 Area 2 Soil Characterization

Soil contamination at Area 2 can be divided into two types: 1) petroleum hydrocarbons found in surface and subsurface soil in both upland and flood plain area, and 2) VOCs, SVOCs, PCBs, and pesticides found along the southern portion of the 1994 soil removal excavation and within the floodplain.

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The most significant contamination encountered during the 1995 RI efforts was in five test pits (57E-95-07X, -12X, -15X, -16X, and -17X) located within the flood plain around the southern portion of the soil removal excavation from at depths ranging from the ground surface to the water table at 4 to 5 ft. bgs. Detected VOCs include toluene, ethylbenzene, and xylenes (TEX), 1,2-DCE (cis- and trans- isomers), TCE, and PCE.

The highest off-site laboratory concentrations of VOCs were observed in 57E-95-07X in the 4-ft.- bgs sample with 0.344 mg/kg of total TEX, 0.0039 mg/kg of 1,2-DCE, 0.011 mg/kg of TCE, and 0.0059 mg/kg of PCE.

The primary SVOCs encountered were naphthalene and methylnaphthalene. The 4-ft.-bgs sample from 57E-95-07X contained the highest concentration of total SVOCs at 12 mg/kg. Elevated concentrations of pesticides and PCBs were also observed. Detected pesticides included dieldrin at a maximum observed concentration of 0.032 mg/kg in the surficial sample from 57E-95-17X, 2,2 bis(para-chlorophenyl)- 1,1-dichloroethene (DDE) at 0.00928 mg/kg in the same sample, and Endosulfan I at 0.081 mg/kg in the 2-ft.-bgs sample from 57E-95-16X. Maximum observed concentrations of PCBs were 3.2 mg/kg of Aroclor-1248 and 12 mg/kg of Aroclor-1260, both from the 2-ft.-bgs sample from 57E-95-16X.