S A JV 2024a 2023 Annual Report Main Post.pdf

United States Army Corps of Engineers

New England District

2023 Annual Operations, Maintenance, and Monitoring

Report Main Post

Former Fort Devens Army Installation

Devens, Massachusetts

Contract No. W912WJ-19-D-0014

Contract Delivery Order No. W912WJ-23-F-0055

July 2024

2023 Annual Operations, Maintenance, and Monitoring Report

Main Post, Former Fort Devens Army Installation i

2023 Annual Operations, Maintenance, and

Monitoring Report

Main Post

Former Fort Devens Army Installation

Devens, Massachusetts

July 2024

Prepared By: Prepared For:

SERES-Arcadis 8(a) JV 2, LLC United States Army Corps of Engineers, 669 Marina Drive, Suite B-7 New England District

Charleston, SC 29492

Tel 843 216 8531

CERTIFICATION

I hereby certify that the enclosed Report, shown and marked in this submittal, is that proposed to be incorporated with Contract Number W912WJ-19-D-0014. This document was prepared in accordance with the United States Army Corps of Engineers (USACE) Scope of Work and is hereby submitted for

Government approval.

Reviewed By:

Andy Vitolins, PG

Project Manager

Heather Levesque, PMP

Deputy Project Manager

Received By:

Penelope Reddy

USACE Project Manager

NOTICE

The United States Department of Defense, Department of Army, funded wholly or in part the preparation of this document and work described herein under Contract No.

W912WJ-19-D-0014. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

ii

Contents Acronyms and Abbreviations ............................................................................................................................... vii

1 Introduction

1.1 Long-Term Monitoring Program Background

1.2 Site Description and History

1.3 Groundwater Hydrology

1.4 2023 Long-Term Monitoring Activities

1.4.1 Groundwater Sampling

1.4.2 Laboratory Testing

1.4.3 Data Validation

1.4.4 Data Evaluation

2 Area of Contamination 57

2.1 Site Background

2.2 Groundwater Hydrology

2.3 Groundwater and Surface Water Sampling

2.3.1 Spring 2023 Data Summary

2.3.2 Water Quality Parameters

2.4 Land-Use Controls, Interviews, and Inspection

2.5 Conclusions and Recommendations

3 Area of Contamination 69W

3.1 Site Background

3.2 Groundwater Hydrology

3.3 Groundwater Sampling

3.3.1 Fall 2023 Data Summary

3.3.2 Water Quality Parameters

3.3.3 Land-Use Controls, Interviews, and Inspection

3.4 Conclusions and Recommendations

4 Area of Contamination 43G

4.1 Site Background

4.2 Groundwater Hydrology

4.3 Groundwater Sampling

4.3.1 Fall 2023 Data Summary

iii

4.3.2 Water Quality Parameters

4.4 Land-Use Controls, Interview, and Inspection

4.5 Conclusions and Recommendations

5 Areas of Contamination 32 and 43A

5.1 Site Background

5.2 Groundwater Hydrology

5.3 Groundwater Sampling

5.3.1 Spring 2023 Data Summary

5.3.2 Water Quality Parameters

5.4 Land-Use Controls, Interviews, and Inspection

5.5 Conclusions and Recommendations

6 Devens Consolidation Landfill

6.1 Site Background

6.2 Groundwater Hydrology

6.3 Groundwater Sampling

6.3.1 2023 Long-Term Monitoring Data Summary

6.3.2 Water Quality Parameters

6.4 Leachate System Monitoring

6.5 Landfill Inspection and Gas Monitoring

6.6 Land-Use Controls, Interviews, and Inspection

6.7 Conclusions and Recommendations

7 Housing Areas and 37-Millimeter Impact Area

7.1 Site Background

7.2 Land-Use Controls

7.2.1 37-Millimeter Impact Area

7.2.2 Restricted Area

7.2.3 Unrestricted/Residential Use Area

7.3 Conclusions and Recommendations

8 Areas of Contamination 44 and 52

8.1 Site Background

8.2 Land-Use Controls, Interviews, and Inspection

9 Study Area 71

9.1 Site Background

iv

9.2 Land-Use Controls, Interviews, and Inspection

10 References

Exhibits (in text) Exhibit 2-1 AOC 57 Area 3 Contaminant of Concern CG Exceedances, Spring 2023

Exhibit 3-1 AOC 69W Contaminant of Concern CG Exceedances, Fall 2023

Exhibit 4-1 AOC 43G Contaminant of Concern CG Exceedances, Fall 2023

Exhibit 5-1 AOC 32/43A Vertical Gradients, Spring 2023

Exhibit 5-2 AOC 32/43A Contaminant of Concern CG Exceedances, Spring 2023

Exhibit 6-1 Water Level Readings for Select DCL Monitoring Wells, Spring and Fall 2023 LTM

Tables

Table 1 Groundwater Elevations Spring 2023 LTM Event

Table 2 Groundwater Elevations Fall 2023 LTM Event

Table 3 Monthly Precipitation Data

Table 4 Analytical Methods, Containers, Holding Times, and Preservatives

Table 5 Monitoring Wells and Surface Water Locations Selected for Long-Term Monitoring

Table 6 AOC-Specific Action Levels

Table 7 DCL Leachate Discharge Permit No. 17 Limits

Table 8 AOC 57 Area 3 Groundwater Analytical Results, Spring 2023

Table 9 AOC 57 Area 3 Surface Water Analytical Results, Spring 2023

Table 10 AOC 69W Groundwater Analytical Results, Fall 2023

Table 11 AOC 43G Groundwater Analytical Results, Fall 2023

Table 12 AOC 32/43A Groundwater Analytical Results, Spring 2023

Table 13 DCL Groundwater Analytical Results, Spring 2023

Table 14 DCL Groundwater Analytical Results, Fall 2023

Table 15 DCL Leachate Analytical Results, Fall 2023

Table 16 DCL Leachate Annual Discharge Quantities v

Figures Figure 1 Site Location, Former Fort Devens Army Installation

Figure 2 Site Layout, AOC 57 – Areas 1, 2, & 3

Figure 3 Site Layout, AOC 57 – Area 2

Figure 4 Site Layout, AOC 57 – Area 3

Figure 5 Groundwater Elevation Contour Map, AOC 57 – Areas 2 & 3, Spring 2023

Figure 6 Metals Concentrations in Groundwater and Surface Water, AOC 57 – Area 3, Spring 2023

Figure 7 Site Layout, AOC 69W

Figure 8 Groundwater Elevation Contour Map, AOC 69W, Fall 2023

Figure 9 Metals Concentrations in Groundwater, AOC 69W, Fall 2023

Figure 10 Site Layout, AOC 43G

Figure 11 Groundwater Elevation Contour Map, AOC 43G, Fall 2023

Figure 12 VPH and Metals Concentrations in Groundwater, AOC 43G, Fall 2023

Figure 13 Site Layout, AOC 32/43A

Figure 14 Groundwater Elevation Contour Map, Overburden Wells, AOC 32/43A, Spring 2023

Figure 15 Groundwater Elevation Contour Map, Bedrock Wells, AOC 32/43A, Spring 2023

Figure 16 VOCs, VPH, and Metals Concentrations in Groundwater, AOC 32/43A, Spring 2023

Figure 17 Site Layout, Devens Consolidated Landfill

Figure 18 Groundwater Elevation Contour Map, Bedrock Wells, Devens Consolidated Landfill, Spring 2023

Figure 19 Groundwater Elevation Contour Map, Bedrock Wells, Devens Consolidated Landfill, Fall

Figure 20 Site Location, Grant Housing Area/Oak and Maple Housing Area/37-mm Impact Area

Figure 21 Site Location, AOCs 44 and 52 – Barnum Road Maintenance Yards

Figure 22 Site Location, SA 71 – Former Railroad Roundhouse

Appendices

Appendix A Groundwater Field Forms

Appendix B Laboratory Analytical Reports

Appendix C Summary of Quality Control Exceedances and Data Validation Reports

Appendix D Summary of Historical Groundwater Sampling Results

Appendix E Mann-Kendall Data Trend Analyses

Appendix F Annual Land Use Control Documentation vi

Appendix G DCL Inspection Report

Appendix H Response to Comments vii

Acronyms and Abbreviations µg/L microgram per liter

AAFES Army Air Force Exchange Service

AOC area of contamination

Army United States Army

BRAC Base Realignment and Closure

BTEX benzene, toluene, ethylbenzene, and xylenes

CCV continuing calibration verification

CFS Commonwealth Fusion Systems

CG cleanup goal

COC contaminant of concern

COD chemical oxygen demand

CSM conceptual site model

DCB dichlorobenzene

DCL Fort Devens Consolidation Landfill

DO dissolved oxygen

DoD Department of Defense

ELAP Environmental Laboratory Accreditation Program

EPH extractable petroleum hydrocarbon

ESMA Excavated Soils Management Area

Eurofins Eurofins TestAmerica Laboratories, Inc.

Fort Devens former Fort Devens Army Installation

FS feasibility study ft/ft foot per foot

HA Housing Area

Harding Harding Environmental Science & Engineering, Inc.

HGL HydroGeoLogic, Inc.

HLA Harding Lawson Associates, Inc.

Horne Horne Engineering Services, Inc.

J estimated concentration

KGS KOMAN Government Solutions, LLC

LCS laboratory control sample

LCSD laboratory control sample duplicate

LDC Laboratory Data Consultants, Inc.

LTM long-term monitoring viii

LTM Plan Long-Term Monitoring Plan

LTMMP Long-Term Monitoring and Maintenance Plan

LTM Report 2022 Annual Long-Term Monitoring Report

LUC land-use control

LUCIP Land-Use Control Implementation Plan

LUCIP Addendum Land-Use Control Implementation Plan Addendum

MassDEP Massachusetts Department of Environmental Protection

MassDevelopment Massachusetts Development and Finance Agency

MCL maximum contaminant level

MEC munitions and explosives of concern mg/L milligram per liter mm millimeter

MNA monitored natural attenuation

MPE measuring point elevation

MS matrix spike

MSD matrix spike duplicate mV millivolt

NAUL Notice of Activity and Use Limitation

NAVD88 North American Vertical Datum of 1988

ORP oxidation-reduction potential

RTN Release Tracking Number

PAH polycyclic aromatic hydrocarbon

PCB polychlorinated biphenyl

QAPP Quality Assurance Project Plan for the Annual Long-Term Monitoring and Maintenance

Program

QC quality control

RI remedial investigation

ROD Record of Decision

SA Study Area

S-A JV SERES-Arcadis 8(a) Joint Venture 2, LLC

SVOC semivolatile organic compound

TDS total dissolved solids

UJ/J estimated

USAEC United States Army Environmental Command

USACE United States Army Corps of Engineers

USEPA United States Environmental Protection Agency ix

UST underground storage tank

UXO unexploded ordnance

VOC volatile organic compound

VPH volatile petroleum hydrocarbons

Weston Weston Solutions, Inc.

yd3 cubic yard

1 Introduction This 2023 Annual Long-Term Monitoring Report (LTM Report) details the performance of ongoing long-term monitoring (LTM) activities at the former Fort Devens Army Installation (Fort Devens) Main Post, located in

Devens, Massachusetts (Figure 1). LTM activities were performed in accordance with the Long-Term Monitoring and Maintenance Plan (LTMMP; Sovereign/HydroGeoLogic, Inc. [HGL] 2015) and the Quality Assurance Project

Plan for the Annual Long-Term Monitoring and Maintenance Program (QAPP; SERES-Arcadis 8(a) Joint Venture

2, LLC [S-A JV] 2020. S-A JV prepared this LTM Report on behalf of the United States Army Corps of Engineers

(USACE) – New England District, under Contract Number W912WJ-19-D-0014.

1.1 Long-Term Monitoring Program Background

The LTM program instituted at Fort Devens is a result of the individual Records of Decision (RODs) issued for each area of contamination (AOC) and study area (SA) discussed in this LTM Report. These AOCs consist of:

AOC 57: Building 3713 Fuel Oil Spill:

2001 ROD by Harding Environmental Science & Engineering, Inc. (Harding [2001])

AOC 69W: Fort Devens Elementary School (Building 215) Fuel Oil Spill Site:

1999 ROD by Harding Lawson Associates, Inc. (HLA [1999a])

AOC 43G: Historical Gas Station G:

1996 ROD by United States Environmental Protection Agency (USEPA [1996])

AOCs 32 and 43A: Defense Reutilization and Marketing Office Yard and former Petroleum, Oils, and

Lubricants Storage Area:

1998 ROD by Horne Engineering Services, Inc. (Horne [1998])

The Fort Devens Consolidation Landfill (DCL):

1999 ROD by HLA (HLA 1999b)

Grant Housing Area (HA) and 37-millimeter (mm) Impact Area:

2009 ROD by Weston Solutions, Inc. (Weston [2009])

AOC 44-52: Barnum Road Maintenance Yards

1995 ROD by United States Army Environmental Center (USAEC [1995])

SA 71: Former Railroad Round House

2015 ROD by Sovereign Consulting, Inc. (Sovereign [2015])

The RODs established site-specific remedial actions for each AOC and SA, as well as the LTM program and land-use controls (LUCs). The effectiveness of the remedial actions is reviewed periodically in Five-Year Review

Reports (HLA 2000; Nobis Engineering, Inc. 2005; HGL 2010; H&S Environmental, Inc. 2015; KOMAN

Government Solutions, LLC [KGS] 2021).

LTM activities in 2023 were conducted at each of the above AOCs in accordance with the LTMMP (Sovereign/

HGL 2015) and included the following:

AOC 57. Annual water level measurements at 19 locations at Areas 2 and 3, and groundwater sampling at

Area 3, were conducted during the spring LTM event. Groundwater samples were analyzed for total metals

(arsenic, iron, and manganese) at two Area 3 monitoring wells. One surface water location was also sampled during the spring 2023 LTM event and the samples were analyzed for dissolved metals (arsenic, iron, and manganese). Additional water level gauging, groundwater sampling, and surface water sampling work was completed in 2023 as part of a Post-Record of Decision Supplemental Remedial Investigation Work Plan

(Post-ROD SRI Work Plan), approved by the USEPA and submitted in June 2023 (S-A JV, 2023a). The results of the SRI will be discussed in the Post-ROD SRI Report, scheduled for submittal in 2024.

AOC 69W. Annual water level measurements at 17 locations and groundwater sampling at eight monitoring wells and two well points were conducted during the fall LTM event. Samples from eight wells were analyzed for extractable petroleum hydrocarbons (EPHs) and target analyte polycyclic aromatic hydrocarbons (PAHs).

Samples from each of the eight monitoring wells and two well points were also analyzed for dissolved metals

(arsenic, iron, and/or manganese). Additional monitoring well installation, water level gauging, and groundwater sampling work was completed in 2023 as part of a Post-Record of Decision Supplemental

Remedial Investigation Work Plan (Post-ROD SRI Work Plan), approved by the USEPA and submitted in

June 2023 (S-A JV, 2023b). The results of the SRI will be discussed in the Post-ROD SRI Report, scheduled for submittal in 2024.

AOC 43G. Annual water level measurements at 11 monitoring wells and groundwater sampling at five wells were conducted during the fall LTM event. Groundwater samples were analyzed for volatile petroleum hydrocarbons (VPHs); including target analytes: benzene, toluene, ethylbenzene, and xylenes (BTEX) and naphthalene; alkalinity; and total metals (iron and/or manganese). Additional monitoring well installation, water level gauging, and groundwater sampling work was completed in 2023, as part of a Post-Record of

Decision Supplemental Remedial Investigation Work Plan (Post-ROD SRI Work Plan) approved by the

USEPA and submitted in June 2023 (S-A JV, 2023c). The results of the SRI will be discussed in the Post-

ROD SRI Report, scheduled for submittal in 2024.

AOC 32/43A. Annual water level measurements at 26 locations and groundwater sampling at four monitoring wells were conducted during the spring LTM event. One well location was observed to be dry (well 32M-01-

11XBR). Groundwater samples were analyzed for volatile organic compounds (VOCs), VPHs including target analytes BTEX/naphthalene, and total metals (arsenic and manganese).

DCL. Annual landfill gas vent monitoring, monthly operation and maintenance of the leachate pump station, annual sampling of the leachate, and an annual landfill cap inspection were conducted. The DCL leachate sampling consists of collecting one sample and analyzing the sample for VOCs, semivolatile organic compounds (SVOCs), pesticides/polychlorinated biphenyls (PCBs), total petroleum hydrocarbons, total metals (select list), total suspended solids, pH, total phenolics, and total cyanide. Semiannual water level measurements at seven locations, and semiannual groundwater sampling at four locations were conducted during the spring and fall LTM events. Groundwater samples were analyzed for VPHs including target analytes BTEX/naphthalene, EPHs including target PAHs, pesticides, total metals (select list), total dissolved solids (TDS), anions (chloride and sulfate), nitrate and nitrite, alkalinity, total cyanide, and chemical oxygen demand (COD).

Grant HA and 37 mm Impact Area. Annual screening for unexploded ordnance (UXO) in the 37 mm Impact

Area, performed by sweeping 10% of the site with a metal detector.

In addition to the above activities, annual LUC inspections and interviews were conducted at each of the above

AOCs. LUC inspections and interview were also conducted at AOC 44-52 and SA 71 in accordance with LUCIPs prepared in 2023 (S-A JV, 2023d; S-A JV, 2023e). LUC inspections and interviews were also conducted at the former Oak and Maple HAs, as discussed in Section 7.2.

1.2 Site Description and History

The former Fort Devens Army Installation is located in the towns of Ayer and Shirley in Middlesex County, and

Harvard and Lancaster in Worcester County, Massachusetts, approximately 35 miles northwest of Boston, Massachusetts. The installation occupied approximately 9,260 acres and was composed of the North, Main, and

South Posts (Figure 1). Route 2 divides the South Post from the Main and North Posts. The Nashua River runs through the North, Main, and South Posts. The area surrounding Fort Devens is largely residential.

The area around Fort Devens was occupied by residential homes and farmland until 1917, when Camp Devens was established as a temporary training area for soldiers during World War I and was used for a variety of training missions until 1990. In 1932, the site was named Fort Devens and made a permanent installation with the primary mission of commanding, training, and providing logistical support for non-divisional troop units. The installation also supported the United States Army (Army) Readiness Regional and National Guard units in the New England area. Pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act, as amended by the Superfund Amendments and Reauthorization Act of 1986, Fort Devens was placed on the National Priorities

List on November 21, 1989, because of identified environmental contamination at several sites.

Devens was identified for cessation of operations and closure under Public Law 101-510, the Defense Base

Realignment and Closure (BRAC) Act of 1990, and officially closed in March 1996. As part of the Fort Devens

BRAC program, portions of the property formerly occupied by Fort Devens were retained by the Army for reserve forces training and renamed the Devens Reserve Forces Training Area. Areas not retained as part of the Devens

Reserve Forces Training Area have been either transferred or are in the process of being transferred to the

Massachusetts Development and Finance Agency (MassDevelopment) for reuse and redevelopment, and to other federal agencies as noted below.

1.3 Groundwater Hydrology

Depth to groundwater was measured prior to sampling all wells at the AOCs within a 24-hour period. Plotting the synoptic groundwater elevation data allows for determination of groundwater flow direction and gradient, essential in understanding contaminant migration and evaluating the effectiveness of the monitoring well network.

Groundwater and surface water elevations for the spring and fall 2023 LTM events are presented in Tables 1 and 2, respectively. The 2023 groundwater gradients are expressed in feet per foot (ft/ft) and AOC-specific groundwater elevation data are presented in sections specific to each AOC.

Annual precipitation data for 2004 through 2023, as reported from the Fitchburg Municipal Airport weather station, are presented in Table 3. The data indicate that precipitation across the area in February, May, October, and

November was less than average for the period of record; April and December were near average (within one-half inch) for the period of record; and January, March, June, July, August, and September were greater than average for the period of record. The overall precipitation in 2023 (60.84 inches) was higher than the average of 43.96 inches for the period of record.

1.4 2023 Long-Term Monitoring Activities

1.4.1 Groundwater Sampling

Sampling activities were coordinated with the USACE – New England District, BRAC Environmental Coordinator office, contracted analytical laboratory, and stakeholders for each respective site. The laboratory provided sampling supplies (sample containers, packing material, custody seals, and coolers) to the sampling team per the specific sample requirements presented in Table 4. Sampling equipment consisted of water quality meters, turbidity meters, bladder pumps, peristaltic pumps, and water levels meters that were tested before use. Well construction details (Table 5) were maintained on site during the sampling events to confirm well screen interval information as needed. The condition of the monitoring well network at each LTM site was inspected during the

2023 sampling events. Observations, if noted, are contained within the field sampling logs provided in Appendix

A. Monitoring wells were found to be in good overall condition, and well locks were replaced if needed.

Monitoring wells were purged and sampled in accordance with Low Stress (low flow) Purging and Sampling

Procedure for the Collection of Groundwater Samples from Monitoring Wells (USEPA 2017b). Low-flow bladder or peristaltic pumps were used, as described in the LTMMP (Sovereign/HGL 2015). Samples submitted for dissolved metals analyses were field filtered through 0.45-micron filters directly into preserved sample bottles.

Non-dedicated sampling and monitoring equipment was decontaminated in accordance with the QAPP (S-A JV

2020). Field duplicate samples were collected during sampling events at each AOC, at the rate of 10% (i.e., one per 10 samples), to evaluate field precision. Matrix spike (MS)/matrix spike duplicate (MSD) pairs (one set per

AOC) were also submitted to evaluate matrix effects on field and analytical precision and accuracy.

The field instruments used to measure water quality parameters (temperature, dissolved oxygen [DO], pH, oxidation-reduction potential [ORP], specific conductance, and turbidity) were calibrated twice daily (before and after field use) in accordance with the manufacturer’s instructions and the Calibration of Field Instruments

Standard Operating Procedure (USEPA 2017a). Equipment calibration log forms are provided in Appendix A. No instrument error was noted during the spring or fall LTM events.

Investigation-derived waste was not generated during the 2023 LTM activities. Purge water from wells was returned to the ground near sample collection locations in accordance with the LTMMP (Sovereign/HGL 2015).

1.4.2 Laboratory Testing

Eurofins TestAmerica Laboratories, Inc. Savannah (Eurofins) was the primary contract laboratory for the analysis of water samples for the spring and fall 2023 LTM events. Eurofins is compliant with the Quality Systems Manual for Environmental Laboratories, Version 5.4 (Department of Defense [DoD] 2021) under the DoD Environmental

Laboratory Accreditation Program (ELAP) and holds current accreditation in accordance with the National ELAP for all applicable analytical methods.

For the Fall 2023 LTM event, Eurofins subcontracted all VPH samples to Katahdin Analytical Services, located in

Westbrook, Maine, which were analyzed using the Massachusetts Department of Environmental Protection

(MassDEP) analytical methods. Katahdin Analytical Services holds the MassDEP certification and DoD ELAP accreditation for these analyses.

Laboratory analytical results for water samples collected during the 2023 LTM events are discussed in Sections 2 through 6. Laboratory analytical reports are provided in Appendix B.

1.4.3 Data Validation

Quality assurance and quality control (QC) samples were collected and analyzed during the spring and fall 2023 groundwater sampling events to evaluate sample collection, transportation, and analysis procedures. Field duplicate samples were collected from monitoring wells 57M-96-11X (AOC 57, spring 2023), ZVM-99-22X (AOC

69W, fall 2023), XGM-97-12X (AOC 43G, fall 2023), 32M-01-18XBR (AOC 32/43A, spring 2023), and LFM-99-

05A (DCL, spring and fall 2023).

Data validation was completed on all laboratory deliverables by Laboratory Data Consultants, Inc. (LDC), located in Carlsbad, California. Analytical results from the 2023 LTM events were evaluated for data acceptability in accordance with the Environmental Data Review Program Guidance (USEPA 2018), the Quality Systems Manual for Environmental Laboratories, Version 5.4 (DoD 2021), and the laboratory’s defined acceptance limits. The method requirements for the USEPA SW-846 QC guidance and the MassDEP VPH and EPH methods were also used as supplemental information. The data validation reports are provided in Appendix C; a summary of quality control exceedances noted during data validation is also included in Appendix C.

LDC reviewed and updated the database with appropriate data qualifiers as needed. Laboratory analyses were confirmed to have been performed in general compliance with the precision, accuracy, representativeness, completeness, comparability, and sensitivity requirements listed in the QAPP (S-A JV 2020). Sample results that were qualified as estimated (UJ/J) due to quality control exceedances are usable with caution. The nitrate-nitrite as N result in sample LFM-99-02B-FAL23 was qualified as rejected (R) due to matrix spike/matrix spike duplicate

(MS/MSD) recoveries less than 30%; the result is not usable. Analytical results reported for the spring and fall

2023 LTM samples were deemed valid and usable for intended purposes with the exception of the nitrate-nitrite as N result in sample LFM-99-02B-FAL23 that was rejected.

1.4.4 Data Evaluation

The analytical results for each AOC were compared to the respective monitoring criteria or cleanup goals (CGs) established in the applicable ROD. Arsenic results in groundwater were compared to the 10 micrograms per liter

(µg/L) maximum contaminant level (MCL) that was promulgated in 2006, which is lower than the cleanup standard that was previously established in the site-specific RODs. Results are discussed in the AOC-specific sections that follow. Table 6 presents the site-specific contaminants of concern (COCs) and the associated CGs or comparison criteria for each AOC. Table 7 presents the DCL leachate discharge limits set by MassDevelopment in accordance with the Industrial Discharge Permit.

2 Area of Contamination 57

2.1 Site Background

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 Harvard, Massachusetts (Figure 1). AOC 57 is located within a Zone II aquifer protection area for the Town of Ayer Grove Pond public water supply wells. The area that includes AOC 57 was used primarily for storage and maintenance of military vehicles. AOC 57 consists of three subareas (Areas 1, 2, and 3) located south to southeast of Building 3713 and former Buildings 3756, 3757, and 3758 (Figure 2). Each subarea includes an upland area that slopes downward to a delineated wetland area bordering Cold Spring

Brook. The subareas received stormwater runoff and waste from vehicle maintenance at former vehicle storage yards related to former Buildings 3713, 3757, and 3758.

A No Further Action ROD was completed for Area 1 (Harding 2001) following the removal of PAH-contaminated soil in 1997. The associated investigation revealed contaminated groundwater, soil, and sediment in Area 2. The

Army completed a limited soil removal action at Area 2 in 1994, and it was discovered that contamination extended beyond the limits originally estimated. Approximately 1,300 cubic yards (yd3) of soil were removed, and the site was transferred to the remedial investigation (RI)/feasibility study (FS) process. During spring 1999, a soil removal action focusing on PCBs and EPH in soil was performed at Area 3 based on data obtained from the RI.

Areas 2 and 3 are shown on Figures 3 and 4, respectively. In June 2000, the Army completed an RI at AOC 57

Areas 2 and 3 that revealed the presence of residual contamination at both sites. A ROD for Areas 2 and 3 was issued in September 2001 and selected excavation (for possible future use) and LUCs for Area 2, and excavation

(to accelerate groundwater cleanup) and LUCs for Area 3. The excavations and product recovery activities are discussed in the Interim Removal Action Completion Report – AOC 57 (Conti Environmental, Inc. 2004). The data collected during the RI activities prompted an Explanation of Significant Differences in March 2004 to add EPH as a COC for Area 2.

Construction of a solar panel manufacturing facility between Areas 2 and 3 and Barnum Road (112 Barnum Road;

Figure 2) was completed in 2009. The current occupant (Jabil, Inc.) produces healthcare products.

An active irrigation well is located adjacent to the building at 78 Barnum Road (Figure 2). The well is 505 feet deep and is believed to be an open borehole bedrock well. The property manager has indicated that the well is used for lawn care for the property from spring to fall and there is no flow meter to record the daily flow rate or volume of water used.

In March 2019, multiple debris areas were identified at AOC 57 between Areas 2 and 3, southeast of the walking path located behind 112 Barnum Road (Figure 2). Debris included rusted vehicle parts (metal debris, tires, and bumpers) and other smaller piles of rusted scrap metal (empty drums and containers). Large concrete slabs were also found. In November and December 2021, debris was removed from AOC 57 in accordance with the Debris

Removal Workplan (S-A JV 2021); additional information is presented in the Final Debris Removal Activities

Summary Report submitted to the USEPA in May 2022 (S-A JV 2022a).

2.2 Groundwater Hydrology

During spring 2023 LTM, water levels were collected at a total of 19 wells and piezometers prior to groundwater sampling, as presented in Table 1. A groundwater elevation contour map is shown on Figure 5 (Areas 2 and 3).

Data indicate that shallow groundwater flows toward Cold Spring Brook to the south/southeast, consistent with historical groundwater flow observations.

The groundwater hydraulic gradients for shallow groundwater within Areas 2 and 3 in spring 2023 were approximately 0.013 ft/ft (between upgradient well 57M-03-01X and downgradient well 57M-03-03X) and

0.026 ft/ft (between upgradient well 57M-95-03X and downgradient well 57M-96-11X), respectively (Figure 5).

The calculated hydraulic gradients and depicted flow directions are consistent with those for previous years.

2.3 Groundwater and Surface Water Sampling

Groundwater and surface water in Area 3 was sampled historically on a semiannual basis from 2003 to 2007, and on an annual basis in the spring since 2008. The sampling program was modified in the LTMMP (Sovereign/HGL

2015) during 2015 to suspend sampling at Area 2; the LTMMP was finalized in accordance with provisions of the

1991 Devens FFA Section 7.8 and released without USEPA comment. Groundwater at AOC 57 is sampled annually in the spring. The spring 2023 LTM event consisted of collecting groundwater samples from two Area 3 monitoring wells (57M-95-03X and 57M-96-11X). Groundwater samples were analyzed for total metals (arsenic, iron, and manganese). One surface water location was also sampled during the spring 2023 LTM event (57-SW1) and was analyzed for dissolved metals (arsenic, iron, and manganese). The spring 2023 groundwater and surface water analytical results for Area 3 are presented in Tables 8 and 9, respectively.

2.3.1 Spring 2023 Data Summary

Exhibit 2-1, below, summarizes the analytes detected in groundwater samples collected from AOC 57 in spring

2023 that exceed the CG specified in the ROD (Harding 2001). Appendix D provides the data for 2003 through

2023, and Appendix E provides the Mann-Kendall trend analyses.

Exhibit 2-1 AOC 57 Area 3 Contaminant of Concern CG Exceedances, Spring 2023

Well Identification

Analyte Groundwater CG

(µg/L)1 Detected Result

(µg/L)

57M-95-03X Arsenic (total) 10 13 J

57M-96-11X Arsenic (total) 10 20

Notes:

1 The CG for arsenic in groundwater is the MCL standard.

J = estimated concentration

Total arsenic concentrations in well 57M-95-03X have been relatively stable, at or less than 60 µg/L with an average of 31 µg/L since the fall 2004 event. Total arsenic concentrations in well 57M-96-11X have varied more broadly through time, fluctuating between 20 and 470 µg/L from 2004 through 2023 (average of 194 µg/L). There is not a statistically significant trend for arsenic at either location.

One surface water sample was collected from location 57-SW1; the dissolved iron concentration (4,900 µg/L) exceeded the surface water benchmark. This is consistent with historical results, which have ranged from 240 to

21,000 µg/L historically and show variability from year to year.

Results of additional analytes screened against groundwater monitoring criteria and surface water benchmarks are presented in Tables 8 and 9, respectively. Figure 6 shows exceedances of the groundwater CG and surface water results compared to the surface water benchmarks for analyses required per the LTMMP (Sovereign/HGL

2015).

2.3.2 Water Quality Parameters

General water quality chemistry parameters (pH, temperature, specific conductivity, ORP, DO, and turbidity) were measured at each well while sampling and were used to determine groundwater stabilization prior to sampling.

Final readings prior to collection of each sample are presented in Table 8.

ORP and DO data can be used to determine whether reducing or oxidizing conditions are present in groundwater.

Low ORP values (less than 50 millivolts [mV]) and DO concentrations less than 1 milligram per liter (mg/L) are generally associated with reducing conditions. Reducing conditions are a typical byproduct of the biodegradation of fuel products and may result in solubilizing of naturally occurring arsenic (and other oxidation-reduction-sensitive metals such as iron and manganese) from native soils to groundwater. This results in elevated concentrations of these metals in groundwater at some locations, while some subsurface zones contain naturally occurring concentrations which are greater than their respective CGs. DO and ORP at well 57M-96-11X (ORP of

9.0 mV and DO of 0.17 mg/L) and well 57M-95-03X (ORP of -106 mV and DO of 0.13 mg/L) indicate that groundwater in these wells is generally reducing or moderately reducing. These locations are hydraulically downgradient of the Area 3 source area.

2.4 Land-Use Controls, Interviews, and Inspection

AOC 57 is owned by the Army but is leased to MassDevelopment per a Lease in Furtherance of Conveyance agreement. Under the Lease in Furtherance of Conveyance agreement, MassDevelopment must comply with the

LUCs of the ROD (Harding 2001) to limit the potential exposure to the residual contaminated soil and groundwater under both existing and future site conditions. The LUCs ensure that exposure to any remaining contaminated soils beneath the site is controlled and prohibit groundwater extraction for industrial or potable water supply use. The initial site-specific annual LUC checklist, including physical on-site inspection and interview components, was developed in 2007 for use during LUC verification activities to ensure control requirements are being met. The checklist was updated in 2023 and included in a LUCIP prepared for AOC 57 (S-A JV, 2023f).

Appendix F contains the completed checklist.

An annual LUC inspection was completed on November 29, 2023, which confirmed the following (Appendix F):

No signs of increased exposure potential to the public from groundwater and/or surface water contaminants.

No damage to on-site monitoring wells

No evidence that groundwater extraction wells are present.

Access to the site is sufficient for monitoring. Some minor vegetation clearance is needed adjacent to a subset of monitoring wells.

No evidence of site use changes or increased exposure potential.

The S-A JV and Army conducted an interview on January 29, 2024 with Neil Angus (Devens Enterprise

Commission), Anne-Marie Dowd (MassDevelopment), and Meg Delorier (MassDevelopment) which confirmed the following (Appendix F):

The interviewees are familiar with the LUCs imposed on the property and documentation of these controls.

No groundwater extraction wells are present.

No proposed plans for property sale, future redevelopment and construction, or demolition activities at the site.

No issues with site access for monitoring.

2.5 Conclusions and Recommendations

After removal of the source area in soil, natural attenuation processes have effectively reduced the remaining concentrations of site COCs (tetrachloroethene, cadmium, 1,4 dichlorobenzene, PCBs, and EPH C11-C22 aromatic carbon range) to less than their respective remediation goals (Sovereign/HGL 2015).

The 2023 LTM results at AOC 57 are consistent with the conceptual site model (CSM; HGL 2008). Total arsenic was detected at concentrations greater than the CG in wells 57M-95-03X and 57M-96-11X, which is consistent with historical observations. There is not a statistically significant trend for arsenic at either location. Groundwater at AOC 57 flows towards Cold Spring Brook; surface water samples collected from location 57-SW-1, adjacent to

Area 3, have not identified arsenic concentrations at levels greater than the USEPA Water Quality Criterion

(monitoring benchmark) of 150 µg/L since long-term monitoring started in 2003. Dissolved iron concentrations at

57-SW-1 have exceeded the monitoring benchmark of 1,000 µg/L in 16 of 20 sampling events completed since

2006, including the spring 2023 LTM event.

The remedial action selected in the ROD included the implementation of LUCs to limit potential exposure to contaminated soil and groundwater under both existing and future site use (Harding 2001). The 2023 LUC inspections and interviews indicate that the LUCs continue to be in place and in effect.

The following recommendations are included for AOC 57:

Continue annual sampling and LUC inspections in accordance with the LTMMP and LUCIP.

Complete vegetation removal to maintain access to monitoring wells in wooded areas.

Update the LTMMP to optimize the monitoring program.

3 Area of Contamination 69W

3.1 Site Background

AOC 69W is located by the northeast corner of the intersection of Jackson Road and Antietam Street on the northern portion of what was formerly the Main Post at Fort Devens (Figure 1), within the Zone II area associated with the MacPherson Well (Figure 7). It is currently being used for the Francis W. Parker Charter Essential School

(former Devens Elementary School [Building 215]), its associated parking lot, and the adjacent lawn extending approximately 300 feet northwest to Willow Brook (Figure 7).

Historical impacts at AOC 69W are attributed to two separate releases of No. 2 heating oil in 1972 and 1978. The

1972 release occurred during the installation of a new 10,000-gallon underground storage tank (UST). The 1978 release resulted from a failed piping joint in the oil pipes that led to the old boiler. Actions, including installation of an oil recovery system, were performed to recover released fuel and oily water from each release (HLA 1999a). A removal action was performed in 1998 for soils and to remove the oil recovery system. The soil removal action was limited by the presence of the building.

The ROD (HLA 1999a) issued for AOC 69W in June 1999 selected limited action as the remedy for subsurface soils and groundwater, and included LTM, LUCs, and five-year reviews. LTM was developed to monitor for off-site migration of contaminants and verify that concentrations decreased through time. The ROD (HLA 1999a) listed arsenic and VPH/EPH to be analyzed. Sampling for VPH was discontinued in 2014; concentrations were less than criteria from 2009 through 2013. Well point 69WP-13-01 was installed in 2013 to monitor for potential migration of manganese based on manganese detected at 69WP-08-01 in 2008.

3.2 Groundwater Hydrology

During the fall 2023 LTM event, water levels were collected from a total of 17 wells and piezometers (Table 2). A water table elevation contour map is shown on Figure 8. Data from the fall 2023 LTM event indicates that groundwater flows in a north-northwest direction, and a groundwater gradient of 0.007 ft/ft was calculated between upgradient monitoring well ZWM-95-17X and downgradient well ZWM-95-18X (Figure 8). The hydraulic gradients and depicted flow directions are generally consistent with those for previous years.

3.3 Groundwater Sampling

Groundwater at AOC 69W is sampled annually in the fall. The fall 2023 LTM event consisted of collecting groundwater samples from eight monitoring wells and two well points (Table 10). In accordance with the LTMMP

(Sovereign/ HGL 2015), the groundwater samples were analyzed for EPH and associated target analyte list

PAHs, and/or dissolved metals (arsenic, iron, and/or manganese).

3.3.1 Fall 2023 Data Summary

Exhibit 3-1, below, summarizes the analytes detected in groundwater samples collected from AOC 69W in fall

2023 that exceed the CG specified in the ROD (HLA 1999a). Results of additional analytes screened against monitoring criteria are presented in Table 10. As shown in Table 10, neither EPH nor PAHs were detected above their respective monitoring criteria in the fall 2023 groundwater samples collected at AOC 69W. Figure 9 shows exceedances of the CG and monitoring criteria for analyses required per the LTMMP (Sovereign/HGL 2015).

Historical data at AOC 69W from 2000 through 2023 are provided in Appendix D. Mann-Kendall trend analyses are provided in Appendix E.

Exhibit 3-1 AOC 69W Contaminant of Concern CG Exceedances, Fall 2023

Well

Identification Analyte

Groundwater CG

(µg/L)1

Detected Result

(µg/L)

ZWM-99-22X Arsenic (dissolved) 10 110

ZWM-99-23X Arsenic (dissolved) 10 23

Note:

1 The CG for arsenic in groundwater is the MCL standard.

Each of the above dissolved arsenic detections greater than the CG are consistent with historical observations.

Out of the four wells (69W-94-13, ZWM-95-15X, ZWM-99-22X, and ZWM-99-23X) evaluated using Mann-Kendall analysis two wells (69W-94-13 and ZWM-99-23X) exhibit a statistically significant decreasing trend for dissolved arsenic.

3.3.2 Water Quality Parameters

Table 10 presents the readings for final field measured general water quality chemistry parameters (pH, temperatures, specific conductivity, ORP, DO, and turbidity) taken before collection of each groundwater sample.

At AOC 69W, as described in Section 2.3.2 for AOC 57, low DO and ORP, indicating reducing conditions in groundwater, generally correlate with increased detected concentrations of metals. Monitoring well ZWM-99-22X, for example, had relatively low ORP and DO concentrations (-29.2 mV and 0.46 mg/L, respectively) and the highest concentration of arsenic detected (110 µg/L; 120 µg/L in duplicate sample) in fall 2023.

3.3.3 Land-Use Controls, Interviews, and Inspection

Ownership of AOC 69W was transferred from the Army to MassDevelopment in August 2007. MassDevelopment later transferred ownership of AOC 69W to the Francis W. Parker Charter Essential School, the current owner.

LUCs were implemented to limit potential exposure to contaminated soil and groundwater under existing and future site conditions, per the ROD (HLA 1999a) and a subsequent deed (Army and MassDevelopment 2007).

LUCs ensure that the remaining contaminated soils beneath and adjacent to the building are not excavated and prohibit groundwater extraction from the site for industrial or potable water supply use. Land use is evaluated as part of the five-year review process to ensure control requirements are being met. A site-specific annual LUC checklist (Appendix F), including physical on-site inspection and interview components, was initially developed in

2007 for use during LUC verification activities. The checklist was updated in 2023 and included in a LUCIP prepared for AOC 69W (S-A JV, 2023g). Appendix F contains the completed checklist.

An annual LUC inspection was performed on November 28, 2023, which confirmed the following (Appendix F):

No evidence (repaved cut marks or penetrations in the pavement) within the Excavated Soils Management

Area (ESMA) that have not been otherwise identified and properly documented by the property owner.

No evidence of damage to the remedy or change to the area overlying the ESMA.

No evidence that groundwater extraction wells are present.

Access to the site is sufficient for monitoring. The S-A JV completed a vegetation removal event in October

2023 to improve access to monitoring wells in the wooded area north of the ESMA; the work was coordinated with MassDevelopment and the property owner.

No signs of increased exposure potential.

An interview was conducted on January 29, 2024 with Neil Angus (Devens Enterprise Commission), Anne-Marie

Dowd (MassDevelopment), and Meg Delorier (MassDevelopment). In addition, Michelle McKenna (Business

Manager of Francis W. Parker Charter Essential School) was contacted via email on January 11, 2024. The interviews confirmed the following (Appendix F):

The interviewees are familiar with the LUCs imposed on the property and documentation of these controls.

No groundwater extraction wells are present.

No proposed plans for property sale, future redevelopment, and construction or demolition activities at the site.

No excavations (planned or emergency) north of the school were conducted within the ESMA.

No issues with site access for monitoring.

Michelle McKenna indicated that a retaining wall/sidewalk project (previously on hold) is anticipated to be completed in 2024. The MassDEP, USEPA and USACE approved a soil management plan and health and safety plan for this project on January 11, 2024.

3.4 Conclusions and Recommendations

The 2023 LTM results are consistent with the CSM (HGL 2008). The LTM dataset indicate that arsenic concentrations have either remained table or exhibited a decreasing trend since 2009, VPH is no longer sampled due to being less than criteria, and EPH results have been less than monitoring criteria since the fall 2019 LTM event. The detected dissolved metal concentrations fluctuate in response to oxidation-reduction conditions in the shallow groundwater.

The ROD (HLA 1999a) remedy includes LUCs to limit potential exposure to contaminated soil and groundwater under both existing and future site use. 2023 LUC inspections and interviews indicate the LUCs continue to be in place and in effect.

The following recommendations are included for AOC 69W:

Continue annual groundwater sampling and LUC inspections in accordance with the LTMMP and LUCIP.

Continue annual vegetation removal events to maintain access to monitoring wells in wooded areas.

4 Area of Contamination 43G

4.1 Site Background

AOC 43G is in the central portion of the former Main Post of Fort Devens (Figure 1), at the southwestern corner of

Pine Road and Queenstown Street, as shown on Figure 10. AOC 43G consists of the former Army Air Force

Exchange Service (AAFES) gas station (Areas 2 and 3) and historical Gas Station G (Area 1) and has been the subject of RIs associated with petroleum contamination resulting from past operations. The former gas station was used as a motor pool fueling station during the World War II era. USTs identified at AOC 43G were removed.

In October 1996, the Army conducted an FS to evaluate potential remedial alternatives and signed a ROD

(USEPA 1996) to document the selected remedy. The selected remedial action includes intrinsic bioremediation, groundwater and contaminant modeling, and long-term groundwater monitoring. Intrinsic bioremediation is a remedial approach that relies on natural attenuation processes to remediate contaminants in the subsurface.

Components of the selected remedy include assessment, data collection, groundwater modeling, LTM, annual reporting to the USEPA and MassDEP, and performing five-year reviews.

4.2 Groundwater Hydrology

During fall 2023 LTM, water level measurements were performed at a total of 11 wells at AOC 43G. Table 2 presents the groundwater elevations and Figure 11 shows a groundwater elevation contour map. The groundwater flow direction is to the east/southeast consistent with the local topography, eventually discharging to surface water via an unnamed tributary to Robbins Pond and to Robbins Pond itself. The calculated hydraulic gradient (0.051 ft/ft between upgradient well XGM-97-12X and downgradient well AAFES-7; Figure 11) and depicted flow direction are generally consistent with those for previous years.

4.3 Groundwater Sampling

Groundwater at AOC 43G is sampled annually in the fall. Fall 2023 LTM at AOC 43G consisted of collecting groundwater samples from five monitoring wells (Table 11). In accordance with the LTMMP (Sovereign/HGL

2015), the groundwater samples were analyzed for VPH and target analyte VOCs, alkalinity, and total metals (iron and/or manganese).

4.3.1 Fall 2023 Data Summary

Exhibit 4-1, below, presents the analytes detected in groundwater samples collected from AOC 43G in fall 2023 that exceed the CGs specified in the ROD (USEPA 1996). Results of additional analytes screened against monitoring criteria are presented in Table 11. Figure 12 shows exceedances of the CGs and monitoring criteria for analyses required per the LTMMP (Sovereign/HGL 2015). Appendix D contains the AOC 43G historical data from

1999 through 2023, while Appendix E presents the Mann-Kendall statistical trend analyses of selected wells.

Exhibit 4-1 AOC 43G Contaminant of Concern CG Exceedances, Fall 2023

Well

Identification Analyte

Groundwater

CG (µg/L)1

Detected Result

(µg/L)

AAFES-2

Iron (total) 9,100 16,000

Manganese (total) 375 4,400

XGM-93-02X Manganese (total) 375 940

XGM-94-04X Manganese (total) 375 440

XGM-97-12X

Iron (total) 9,100 37,000

Manganese (total) 375 2,000

Benzene 5 6.3

Note:

1 The CG for iron is the background level. The CG for manganese is a site-specific goal established as part of the Long-Term Monitoring Plan (LTM Plan; HGL 2008).

Total manganese exceeded the 375 µg/L CG in four of five sampled wells. Concentrations were observed to be consistent with historical data. Of the wells evaluated using Mann-Kendall, three of five wells, AAFES-2, XGM-93-

02X, and XGM 97-12X had statistically significant decreasing trends for total manganese. There was not a statistically significant trend at well XGM-94-04X or well AAFES-7.

Total iron exceeded the 9,100 µg/L CG in two of four sampled wells. Out of the three wells, AAFES-2, XGM-93-

02X, and XGM 97-12X evaluated using Mann-Kendall, two wells AAFES-2 and XGM-93-02X had statistically significant decreasing trend in total iron concentrations.

Total benzene exceeded the 5 µg/L CG in one of four sampled wells (XGM-97-12X).