S A JV 2024d 2023 Annual Report AOC A7 Sudbury.pdf

FINAL

United States Army Corps of Engineers

New England District

2023 Annual Long-Term

Monitoring and Maintenance

Report Area of Contamination A7

Former Sudbury Training Annex

Sudbury, Massachusetts

Contract No. W912WJ-19-D-0014

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

July 2024

FINAL 2023 Annual Long-Term Monitoring and Maintenance Report

Area of Contamination A7, Former Sudbury Training Annex i

2023 Annual Long-Term

Monitoring and Maintenance Report

Area of Contamination A7

Former Sudbury Training Annex

Sudbury, 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, South Carolina 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 ................................................................................................................................ iv

1 Introduction

1.1 Site Background

2 Long-Term Groundwater Monitoring Activities

2.1 Groundwater Sampling

2.2 Equipment Decontamination

2.3 Investigation-Derived Waste

2.4 Groundwater Elevation Measurements

3 Groundwater Monitoring Results

3.1 Analyses

3.2 Analytical Results

4 Quality Assurance/Quality Control

5 Landfill Maintenance and Inspection Activities

5.1 Summary of Maintenance Activity and Findings

5.2 Summary of Recommendations

6 Institutional Controls

6.1 Document Reviews

6.2 Institutional Control Interviews

6.3 Physical On-Site Inspections

6.4 Institutional Control Summary

7 Conclusions

8 References iii

Tables

Table 1 Sample Analysis Methods, Containers, Holding Times, and Preservatives

Table 2 AOC A7 Groundwater Monitoring Locations

Table 3 AOC A7 Groundwater Elevations, Fall 2023

Table 4 AOC A7 Groundwater Analytical Results, Fall 2023

Figures

Figure 1 Site Location, Former Sudbury Training Annex

Figure 2 Site Layout, AOC A7

Figure 3 Site Layout, AOC P31 and AOC P58

Figure 4 Interpretive Water Table Elevation, Sudbury Annex – AOC A7, Fall 2023

Appendices

Appendix A Groundwater Field Sampling Forms

Appendix B Laboratory Analytical Report

Appendix C Summary of Historical Groundwater Target Compounds at AOC A7, 1996 – 2022

Appendix D Data Validation Report

Appendix E 2023 Geotechnical Engineering Annual Inspection Report

Appendix F Annual Land Use Control Checklist and Interviews

Appendix G Land Transfer Agreements iv

Acronyms and Abbreviations

1995 SC ROD Record of Decision – Source Control Operable Unit, AOC A7, the Old Gravel Pit

Landfill, AOC A9, the POL Burn Area

2023 Annual Report 2023 Annual Long-Term Monitoring and Maintenance Report

4,4’-DDD 4,4’-Dichlorodiphenyldichloroethane

4,4’-DDE 4,4’-Dichlorodiphenyldichloroethylene

AOC area of contamination

ARAR Applicable or Relevant and Appropriate Requirement

Army United States Army

BHC Hexachlorocyclohexane

CCV continuing calibration verification

COC contaminant of concern

COD chemical oxygen demand

DoD Department of Defense

DOE Department of Energy

FEMA Federal Emergency Management Agency ft/ft foot per foot

IC institutional control

KGS KOMAN Government Solutions, LLC

LOD limit of detection

LTM long-term monitoring

LTMM long-term monitoring and maintenance

LTMMP Long-Term Monitoring and Maintenance Plan

LUC land use control

MassDEP Massachusetts Department of Environmental Protection

MCP Massachusetts Contingency Plan mg/L milligram per liter

MS matrix spike

MSD matrix spike duplicate

OU Operable Unit

QC quality control

Quality Systems Manual Department of Defense (DoD) and Department of Energy (DOE) Consolidated

Quality Systems Manual for Environmental Laboratories, Version 5.4

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

SC Source Control

Sudbury Annex former United States Army Sudbury Training Annex

USACE United States Army Corps of Engineers

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service

VOC volatile organic compound

1 Introduction

SERES-Arcadis 8(a) JV 2, LLC (hereafter referred to as the S-A JV) prepared this 2023 Annual Long-Term

Monitoring and Maintenance Report (2023 Annual Report) to present results of the long-term monitoring and maintenance (LTMM) activities conducted in 2023 for Area of Contamination (AOC) A7, known as the Old Gravel

Pit Landfill, located at the former United States Army (Army) Sudbury Training Annex (Sudbury Annex). The report also presents inspection activities conducted at AOCs P31 and P58 (together termed the Sudbury Road

Dump). The S-A JV prepared this report on behalf of the United States Army Corps of Engineers (USACE) – New

England District, under Contract Number W912WJ-19-D-0014.

The activities discussed in this 2023 Annual Report were conducted in accordance with the Long-Term Monitoring and Maintenance Plan (LTMMP; KOMAN Government Solutions, LLC [KGS] 2020). The LTMM activities were conducted to fulfill the requirements of the Record of Decision – Source Control Operable Unit: AOC A7, the Old

Gravel Pit Landfill; AOC A9: the Petroleum, Oil and Lubricants Burn Area (1995 SC ROD; O.H. Materials

Remediation Services Corporation 1995). This 2023 Annual Report also includes Institutional Control (IC) verification activities for AOCs P31 and P58.

1.1 Site Background

The Sudbury Annex was listed as a National Priorities List site from February 1990 through January 2002 under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended by the

Superfund Amendments and Reauthorization Act of 1986. The former training annex occupies approximately

4.3 square miles (2,752 acres) in the Massachusetts towns of Hudson, Marlborough, Maynard, Stow, and

Sudbury. A site location map indicating the general site location and physical setting is presented as Figure 1.

Hudson Road/Sudbury Road divides the installation into a larger northern section and a smaller southern section.

The Sudbury Annex became part of the United States Army Garrison Fort Devens in 1982.

The Sudbury Annex was removed from the National Priorities List in January 2002. At that time, 2,205 acres were transferred to the United States Fish & Wildlife Service (USFWS), 4.1 acres were transferred to the United States

Air Force, and 71.4 acres were transferred to the United States Department of Homeland Security Federal

Emergency Management Agency (FEMA).

AOC A7, the Old Gravel Pit Landfill, is a 10-acre landfill located between Patrol Road and the Assabet River along the northern installation boundary (Figure 2). Access to the AOC A7 landfill is from Patrol Road or the

Assabet River Rail Trail via locked gates. The northern edge of the landfill is less than 100 feet from the Assabet

River at its closest point. The landfill is located on the northern lower slope and toe of a hill that slopes downward to the Assabet River.

The 1995 SC ROD for the source control (SC) of the operable unit (OU) at AOC A7 (O.H. Materials Remediation

Services Corporation 1995) was signed by the Army and the United States Environmental Protection Agency

(USEPA) in September 1995. The Massachusetts Department of Environmental Protection (MassDEP) concurred with the 1995 SC ROD. The groundwater at AOC A7 was addressed via a management of migration OU ROD for groundwater at AOCs A7 and A9 (O.H. Materials Remediation Services Corporation 1997), which specified no further action including no land use controls (LUCs).

The selected source remedy included:

Removal and off-site disposal of chemical waste debris in the laboratory dump area

Construction of a Resource Conservation and Recovery Act of 1976 Subtitle C landfill cap to contain the remaining site contaminants of concern (COCs)

Operation and maintenance

Institutional controls and land use restrictions to limit future use of land at AOC A7

Long-term groundwater monitoring

Five-year reviews to assess whether the remedy remains protective of human health and the environment.

The 1995 SC ROD (O.H. Materials Remediation Services Corporation 1995) required LUCs to limit future use of

AOC A7. The LUCs for AOC A7 include a perimeter fence around the landfill cap area and the prohibition of use of groundwater as drinking water, which eliminate ingestion of groundwater exposure pathways. The LUCs required by the 1995 SC ROD are described in the Memorandum of Agreement (MOA) between the Army and the current property owner, the USFWS, dated September 28, 2000. Additional information is provided in Section 6.4.

An addendum to the MOA prepared in 1999 included ICs at AOCs P31 and P58. These two AOCs comprise a section of land on the northeast side of Sudbury Road (Figure 3) where dumping occurred at some time before the closure of the Sudbury Annex, possibly even before the land became Army property. The portion known as

AOC P31 was the subject of a No Further Action decision in April 1999 following the conclusion of a March 1999 supplementary site investigation that documented sampling and metal debris removal actions (USACE 2001).

AOC P58, located northwest of AOC P31, was monitored by the Army through May 2001 for arsenic in groundwater at four wells. Sampling was discontinued at AOC P58 in 2002 and the monitoring wells were decommissioned.

The 1995 SC ROD does not include groundwater remedial action objectives, Applicable or Relevant and

Appropriate Requirements (ARARs), or specific cleanup levels. However, the remedial action objectives include eliminating potential risk to human health and the environment associated with exposure to impacted wastes and minimizing off-site migration. The current monitoring program at AOC A7 consists of the following:

Annual groundwater monitoring for COCs at monitoring well SUDA7-19-01, which was installed in September

2019 as a replacement for abandoned well point SUDWP-A07-01 (KGS 2020)

Biennial sampling at three wells (OHM-A7-08, SUD-A07-014, and SUD-A07-065) for COCs in even years

(2022, 2024, 2026, etc.)

Annual hydraulic gauging at 13 monitoring wells and two staff gauges

Annual visual inspection of the landfill cap and surrounding area

Landfill gas vent monitoring every 5 years, before the 5-year review (in 2025, 2030, etc.)

Annual mowing of the landfill and maintenance.

2 Long-Term Groundwater Monitoring Activities

This section describes the long-term groundwater monitoring activities conducted at AOC A7 in 2023. The 2023 long-term monitoring (LTM) sampling event at AOC A7 is described in Sections 2.1 through 2.3, and the groundwater gauging event is discussed in Section 2.4. In accordance with the LTMMP (KGS 2020), only one well (SUDA7-19-01) was sampled during the 2023 LTM sampling event.

2.1 Groundwater Sampling

Groundwater sampling activities at AOC A7 were performed with a peristaltic pump and dedicated tubing in accordance with the low-flow procedures documented in Low Stress (low flow) Purging and Sampling Procedure for the Collection of Groundwater Samples from Monitoring Wells (USEPA 2017b). Water quality parameters

(temperature, dissolved oxygen, pH, oxidation-reduction potential, specific conductance, and turbidity) were measured during purging and sampling via a water quality meter. The field instruments used to measure water quality parameters were calibrated daily in accordance with the manufacturer’s instructions and in accordance with USEPA’s Standard Operating Procedure – Calibration of Field Instruments (USEPA 2017a). Details on analytical sample containers and preservation requirements are presented in Table 1. Completed groundwater low-flow sampling forms and equipment calibration records are presented in Appendix A.

Descriptions of the locations, depths, screened intervals, and sampling frequencies at AOC A7 are included in

Table 2. Quality control (QC) samples were collected as discussed in Section 4.

2.2 Equipment Decontamination

Non-dedicated sampling and monitoring equipment (limited to water level meters) were decontaminated before and after use. Decontamination was performed in accordance with the LTMMP (KGS 2020).

2.3 Investigation-Derived Waste

Investigation-derived waste generated during groundwater sampling activities consisted of purge water from well sampling, equipment decontamination water, and disposable supplies such as nitrile gloves and paper towels.

Purge water and equipment decontamination water were discharged back to the ground at the site of generation after sampling was completed, in accordance with the LTMMP (KGS 2020). Used disposable supplies were bagged and disposed of as general solid waste.

2.4 Groundwater Elevation Measurements

Depth to water was gauged and recorded for the 13 monitoring wells and two staff gauges listed in the LTMMP

(KGS 2020) on November 8, 2023. The depth to water was measured at each of the gauged monitoring wells and staff gauges within a 24-hour period. The water level measurements and the corresponding water elevation data

(based on surveyed reference elevations) are presented in Table 3. Groundwater elevations and potentiometric surface for the 2023 LTM event are presented on Figure 4.

Figure 4 shows groundwater generally flowing north toward the Assabet River, with the top of the unconfined saturated zone remaining near the surface following site topology. This is consistent with historical groundwater flow observations. The groundwater elevations across AOC A7 yielded a groundwater gradient between 0.07 to

0.08 foot per foot (ft/ft) horizontally. This is steeper than the previously observed gradient of approximately

0.05 ft/ft in 2022.

A 0.15 ft/ft vertical gradient was observed around the OHM-A7-11 and OHM-A7-10 well pair. This vertical gradient indicates upward flow potential (possibly due to the proximity of Assabet River) and is consistent with historical gradients measured from this well pair. It is unknown whether upward gradients are present throughout the site as a whole, as OHM-A7-10 and OHM-A7-11 are the only shallow/deep overburden well pair. The overall groundwater flow direction at AOC A7 has remained generally consistent throughout the 27 years of monitoring performed to date.

3 Groundwater Monitoring Results

This section describes the methods used for sample analysis and provides results of the laboratory testing and analysis. The laboratory analytical reports are provided in Appendix B.

3.1 Analyses

Per the LTMMP, one well (SUDA7-19-01) was sampled during this event. Two samples were collected from the well: one parent sample and one field duplicate sample for QC purposes.

These samples were submitted to Eurofins TestAmerica of Savannah, Georgia, for analysis for volatile organic compounds (VOCs), organochlorine pesticides, and total cyanide. The chemical oxygen demand (COD) analysis was conducted at Eurofins TestAmerica of Arvada, Colorado. The two Eurofins TestAmerica laboratories are compliant with the United States Department of Defense (DoD) and Department of Energy (DOE) Consolidated

Quality Systems Manual for Environmental Laboratories, Version 5.4 (Quality Systems Manual; DoD and DOE

2021) under the DoD Environmental Laboratory Accreditation Program (ELAP) (Savannah, Georgia certification

#L2463, expires September 22, 2024; Arvada, Colorado certification #2907.01, expires October 31, 2024) and hold current accreditation for all applicable analytical methods. The analytical methods and procedures used for the groundwater samples collected at AOC A7 are presented in Table 1.

3.2 Analytical Results

The results of the sample analyses from well SUDA7-19-01 are shown in Table 4. As discussed in Section 1.1, no cleanup concentration requirements are stipulated in the 1995 SC ROD (O.H. Materials Remediation Services

Corporation 1995). For comparative purposes and in accordance with the LTMMP (KGS 2020), groundwater analytical results are compared to project action levels, which are derived from the USEPA maximum contaminant levels (MCLs) and the Massachusetts Contingency Plan (MCP) GW-1 and GW-3 standards. Historical results for targeted analytes (defined as analytes with historical detections above the MCLs and/or MCP GW-1 standards

[1,1,2,2 trichloroethane, tetrachloroethene, trichloroethene, gamma-BHC (Lindane) and 4,4’-

Dichlorodiphenyldichloroethane (4,4’-DDD)] are presented in Appendix C. As described in the LTMMP (KGS

2020), it should be noted that groundwater is not used as a source of drinking water at AOC A7 and groundwater discharges to the Assabet River.

A summary of the 2023 analytical results for the parent and duplicate sample collected from well SUDA7-19-01 is provided below:

No analytes were detected above laboratory limits of detection (LODs), with the exception of total cyanide in the parent sample at a concentration of 0.0025 J (estimated) milligrams per liter (mg/L). The total cyanide detection is well below the MCP GW-1 and MCP GW-3 standards of 0.20 and 0.030 mg/L, respectively.

No targeted analyte has been detected at a concentration above MCP GW-3 standards in any monitoring events conducted at AOC A7 since October 2001.

4 Quality Assurance/Quality Control

Eurofins Savannah of Savannah, Georgia, was the primary contract laboratory used for the analysis of groundwater samples for the 2023 monitoring event. This laboratory is compliant with the United States

Department of Defense (DoD) and Department of Energy (DOE) Consolidated Quality Systems Manual for

Environmental Laboratories, Version 5.4 (Quality Systems Manual; DoD and DOE 2021) under the DoD National

Environmental Laboratory Accreditation Program (certification #L2463, expires September 22, 2024) and holds current National Environmental Laboratory Accreditation Program accreditation for all applicable analytical methods.

As a part of the 2023 monitoring event, quality assurance and QC samples were collected and analyzed to evaluate sample collection, transportation, and analysis procedures. A field duplicate sample was collected from well SUDA7-19-01 and analyzed at the laboratory for VOCs, organochlorine pesticides, total cyanide, and COD.

The analytical results for this field duplicate sample are shown in Table 4.

Data validation was completed on all laboratory deliverables by Laboratory Data Consultants, Inc. of Carlsbad, California. The analytical results from the 2023 monitoring event were reviewed and evaluated for data acceptability in accordance with the USEPA Region 1 Environmental Data Review Program Guidance (USEPA

2018), the Quality Assurance Project Plan (S-A JV 2020), and the DoD General Data Validation Guidelines (DoD

2019). The method requirements from the Quality Systems Manual Version 5.4 (DoD and DOE 2021) and the

USEPA Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846 (USEPA 2014) were also used as supplemental information.

The data validation report for the 2023 monitoring event is presented in Appendix D; QC exceedances noted during data validation are noted below:

Recoveries of the pesticides aldrin, alpha-Hexachlorocyclohexane (BHC), alpha-endosulfan, dieldrin, endosulfan sulfate, endrin, gamma-BHC, heptachlor epoxide, and 4,4’-Dichlorodiphenyldichloroethylene

(4,4’-DDE) were less than the control limit in the laboratory control sample analyzed in association with the analysis of sample SUDA7-19-01-FAL23 and field duplicate sample SUD-DUP01-FAL23. In addition, the matrix spike (MS) and/or matrix spike duplicate (MSD) analysis performed on sample SUDA7-19-01-FAL23 exhibited recoveries of aldrin, alpha-BHC, alpha-endosulfan, dieldrin, endosulfan sulfate, endrin, gamma-

BHC, heptachlor, heptachlor epoxide, 4,4’-DDD, and 4,4’-DDE less than the lower control limits. The associated non-detect results were qualified as estimated (UJ) with a potential for low bias in samples

SUDA7-19-01-FAL23 and SUD-DUP01-FAL23.

Recovery of the pesticides surrogate compound 2,4,5,6-tetrachloro-meta-xylene was greater than the control limit in field duplicate sample SUD-DUP01-FAL23. The results for all pesticides reported in sample SUD-

DUP01-FAL23 were qualified as estimated (UJ) with a potential for low bias in the reported results.

The continuing calibration verification (CCV) associated with VOC analysis exhibited results for bromomethane and chloroethane less than the acceptance criteria. In addition, the closing CCV was less than the acceptance criteria for bromomethane. The non-detect results for bromomethane and chloroethane in sample SUDA7-19-01-FAL23 and field duplicate sample SUD-DUP01-FAL23 were qualified as estimated

(UJ).

The MS and/or MSD analysis performed on sample SUDA7-19-01-FAL23 exhibited recoveries of the VOCs

1,2-dichlorobenzene and bromomethane less than the lower control limits. The associated non-detect results were qualified as estimated (UJ) with a potential for low bias in samples SUDA7-19-01-FAL23 and SUD-

DUP01-FAL23.

The MS/MSD analysis performed on sample SUDA7-19-01-FAL23 exhibited recoveries of cyanide less than the lower control limits. The cyanide results were qualified as estimated (J/UJ) with a potential for low bias in samples SUDA7-19-01-FAL23 and SUD-DUP01-FAL23.

Appropriate qualifiers, if needed, have been added to the 2023 analytical data in the project database and are included in Table 4 and Appendix D. Some values were J-qualified (analyte detected at estimated concentration) or UJ-qualified (analyte not detected, laboratory reporting limit is estimated) due to quality control exceedances.

Sample results that were qualified as estimated (UJ/J) are usable with caution. The data from the 2023 monitoring event are acceptable for use with no data being rejected.

5 Landfill Maintenance and Inspection Activities

This section summarizes the landfill maintenance and inspection activities performed at AOC A7 in 2023.

A detailed discussion of the 2023 landfill inspection and recommendations is presented in the Geotechnical

Engineering Annual Inspection Report (Appendix E).

5.1 Summary of Maintenance Activity and Findings

The following maintenance activity was conducted at AOC A7 during 2023:

The cap and adjacent area vegetation were mowed from October 17 to 26, 2023, by Tantara Corporation

(Tantara) of Worcester, Massachusetts.

The following is a summary of findings regarding the vegetative cover, vegetation types, erosion, settlement, and general condition of the various landfill features (based on an inspection completed on November 3, 2023):

The landfill cap was in good condition with no significant erosion or settlement. In general, the cap vegetation appears healthy, dense, and provides good coverage of the landfill cap, with grass and clover predominating.

Minimal/superficial rutting was observed adjacent to one of the monitoring wells (OHM-A7-08) located at the cap.

No encroachment of wetland species on the cap was observed.

The security perimeter fence is in good overall condition. Some branches have fallen on the eastern portion of the fence, but no damage to the fence was observed. Most of the trees were removed by hand and the remaining branches will be removed during the next landfill mowing event.

The cap drainage system was in good condition. Drainage channels are free of sediment and debris. The grass on drainage channel bottoms was in good condition and the vegetation on the side slopes was healthy and dense.

The toe drain appeared to be functioning properly, and no slope stability or erosion problems were observed.

Sections of geotextile that were repaired in 2017 remain in good condition.

The culvert pipe at the southeast corner of the landfill (under the fence line by the road) appeared to be in good working condition.

The gas vent system is in good condition. Each of the four vent pipes was intact, properly identified, and appeared to be functioning as intended. The installed bird/insect screens remain in good condition. As described in the 2020 inspection report (S-A JV 2021), three of the four gas vents are slightly tilted. It is unclear whether the tilts are due to settlement of the landfill, or if they were present at their original construction. The slight tilts are not expected to affect the functioning of the gas vents and no other indications of settlement or erosion were observed; therefore, no action is required at this time.

The stormwater culverts along the western/southwestern cap line appear to be in good condition.

The groundwater monitoring wells were in generally good condition.

5.2 Summary of Recommendations

The following is a summary of recommendations for future maintenance of the landfill:

Continue mowing the landfill cap annually to control vegetative growth, as well as the adjacent fields to prevent woody and wetland plant species from encroaching onto the cap. Mowing should not take place until

September when ground-nesting songbirds are mature enough to avoid being harmed.

Continue annual inspections of the landfill cap components. The inspection should continue to be performed in the fall, soon after mowing (i.e., within 1 to 2 weeks), and preferably within 48 hours after a precipitation event to aid in inspecting the effectiveness of surface runoff in the drainage swales.

Continue general landfill maintenance, such as clearing moss and debris from toe drain areas and clearing large/woody vegetative growth from the cap and drainage channels. Also continue to clear vegetation from the fence line during the annual monitoring and maintenance program to prevent damage to the fence and gates.

Continue to monitor the angle of tilt of the gas vents as part of the annual inspection to check for possible settlement over time.

Since the cap was installed in 1996, post-closure inspection and monitoring have been performed for more than 27 years. In accordance with Resource Conservation and Recovery Act of 1976 Subtitle C landfill cap regulations for post-closure monitoring periods of performance, planning will commence to reduce long-term monitoring and sampling activities (or to perform them at a reduced frequency) after 30 years of monitoring has been completed.

6 Institutional Controls

The 1995 SC ROD (O.H. Materials Remediation Services Corporation 1995) included ICs in the selected remedy for AOC A7 to restrict changes in land use at that AOC. The LTMMP (KGS 2020) includes IC inspection criteria to be performed annually at AOCs A7, P31, and P58 to monitor for significant changes in site use and increases in exposure potential. The IC criteria are described below and include document reviews, interviews, and physical on-site inspections, each to be completed and reported with checklists.

6.1 Document Reviews

The following documents were reviewed in accordance with the LTMMP (KGS 2020):

2020 Final Annual Operations, Maintenance, and Monitoring Report, AOC A7, Former Sudbury Training

Annex, Sudbury, Massachusetts (S-A JV 2021)

Protectiveness Assessment for AOC P31/P58, Former Sudbury Training Annex, Stow, Massachusetts, Concord, Massachusetts (USACE 2007).

In accordance with the LTMMP (KGS 2020), a “Checklist for Review of Sudbury Annex (AOC A7) Annual Report” was prepared to illustrate how the documents were used to evaluate the ICs at AOCs A7, P31, and P58; the results of the completed review of this 2023 Annual Report are summarized in Appendix F.

6.2 Institutional Control Interviews

IC interviews are conducted annually to monitor the status of ICs at AOC A7. Property owners contacted are the

USFWS (for the Assabet River National Wildlife Refuge, the layout of which is shown on Appendix F, Figure F.1) and FEMA (which owns six small parcels of the former training annex in close proximity to AOC A7).

An interview was conducted by email with representatives from the USFWS who are familiar with day-to-day activities. The interview included discussions of the following (Appendix F):

Status of past redevelopment or other construction or demolition activities

Review of approved conditional exemptions, amendments, and/or releases

Review of any unauthorized uses and activities

Review of corrective action to resolve unauthorized uses and activities

Overall effectiveness of the ICs

Status of anticipated future redevelopment or other construction or demolition activities.

Summaries of the USFWS and FEMA interviews are presented in Appendix F. The IC interviews indicated that no significant changes in site use or evidence of increased exposure potential were apparent for the 2023 reporting period at AOC A7.

6.3 Physical On-Site Inspections

Annual physical on-site inspections are conducted at AOCs A7, P31, and P58 in accordance with the LTMMP

(KGS 2020). The physical on-site inspections address the following items:

Land use conditions (presence of buildings and level of recreational use)

Evidence of any changes to the use of AOCs A7, P31, or P58

Evidence of any disturbance to the integrity of the landfill containment system or to the function of the monitoring system in place at AOC A7

Evidence of any significant excavation or surface or subsurface soil disturbance at AOC A7

Evidence of any activities that have disrupted or otherwise negatively impacted the subsurface soil at the

AOCs A7, P31, or P58 below the depth of 4 feet

Other such conditions that the Army, USEPA, and MassDEP Project Managers may deem necessary to evaluate to continue the protectiveness of the ICs. The party conducting the inspection notes all observations, including observation of any known or suspected violations, on an inspection checklist.

Inspections of the AOC A7 landfill and the surrounding area were conducted by the S-A JV and USACE on

November 3, 2023. The landfill cap, drainage features, and surrounding area were found to be in good condition, and there was no evidence of excavation or damage. A summary of the inspection findings is presented in

Section 5, and specific details of the inspections and future planned activities are included in Appendix E.

Inspections of AOCs P31 and P58 were conducted on November 27, 2023, and indicated no evidence of changes to the use of these AOCs. The sites were observed to be vegetated and there was no evidence of dumping or excavation. An inspection checklist is included in Appendix F.

6.4 Institutional Control Summary

The LUCs required by the 1995 SC ROD (O.H. Materials Remediation Services Corporation 1995) are described in the MOA between the Army and the current property owner, the USFWS, dated September 28, 2000

(Appendix G). Document reviews, IC interviews, and physical on-site inspections completed during the 2023 reporting period revealed no significant changes in site use or evidence of increased exposure potential for

AOCs A7, P31, and P58. Land transfer agreements with the USFWS, FEMA, and United States Air Force are also provided in Appendix G. Interviews with USFWS and FEMA who currently use, own, and maintain the land are included in Appendix G.

7 Conclusions

One well (SUDA7-19-01) was sampled during the fall 2023 monitoring event conducted on November 8, 2023. No analytes were detected above LODs, with the exception of total cyanide detected at a trace level of

0.0025 J mg/L. No analytes were detected above the MCP GW-1 or MCP GW-3 comparison criteria.

The groundwater elevation contours were consistent with historical gauging events, with a slightly steeper gradient (0.07 to 0.08 ft/ft) than previously observed in 2022 (0.05 ft/ft).

The AOC A7 landfill cap remains in good condition based on the November 3, 2023, inspection. The drainage system and gas vent monitoring system are in good condition and functioning as intended. The fence is in good overall condition and no damage was observed.

No significant changes in site use or evidence of increased exposure potential were observed at AOCs A7, P31, and P58 based on document reviews, the IC interviews, and on-site inspections.

The next Annual Report, which will present the results of fall 2024 monitoring and maintenance activities, will be submitted for regulatory agency review in May 2025.

Based on the results of the fall 2023 groundwater sampling event at the site and the interviews and inspections conducted, the current monitoring and inspection schedule is appropriate for maintaining protectiveness. The Army is planning to request reduction of sampling in the next Annual Report. As indicated above, the cap is 27 years old and monitoring has been completed for the past 27 years and concentrations over the period of the biennially sampling remain the same (as shown in Appendix C).

8 References

DoD. 2019. General Data Validation Guidelines. November. Available online at:

https://denix.osd.mil/edqw/documents/documents/gen-data-validation-rev1/.

DoD and DOE. 2021. Department of Defense (DoD) and Department of Energy (DOE) Consolidated Quality

Systems Manual for Analytical Laboratories, Version 5.4. October. Available online at:

https://www.denix.osd.mil/edqw/denix-files/sites/43/2021/10/QSM-Version-5.4-FINAL.pdf.

KGS. 2020. Long-Term Monitoring and Maintenance Plan for Area of Contamination A7. Former Sudbury Training

Annex, Sudbury, Massachusetts. July.

O.H. Materials Remediation Services Corporation. 1995. Record of Decision – Source Control Operable Unit, AOC A7, the Old Gravel Pit Landfill, AOC A9, the POL Burn Area, Fort Devens Sudbury Training Annex, Sudbury, Massachusetts. September.

O.H. Materials Remediation Services Corporation. 1997. Record of Decision – Area of Contamination A4 and

Areas of Contamination A7 and A9, Management of Migration Operable Units, U.S. Army Sudbury Annex, Middlesex County, Massachusetts. September.

S-A JV. 2020. Quality Assurance Project Plan Annual Long-Term Monitoring and Maintenance Program, Environmental Services at Former Fort Devens Army Installation – BRAC Legacy Sites, Devens, Massachusetts. October.

S-A JV. 2021. 2020 Final Annual Operations, Maintenance, and Monitoring Report, Former Sudbury Training

Annex, Sudbury, Massachusetts. August.

USACE. 2001. New England District. First Five-Year Review Report for Sudbury Training Annex, Sudbury, Massachusetts. September.

USACE. 2007. New England District. Protectiveness Assessment for AOC P31/P58, Former Sudbury Training

Annex, Stow, Massachusetts, Concord, Massachusetts. April.

USEPA. 2014. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846, Fifth Edition, Update V. Office of Solid Waste and Emergency Response. July. Available online at: www.epa.gpv/hw-sw846/sw-846-compendium.

USEPA. 2017a. Region 1. Standard Operating Procedure - Calibration of Field Instruments (temperature, pH, dissolved oxygen, conductivity/specific conductance, oxidation/reduction potential [ORP], and turbidity).

March 23. Available online at: https://www.epa.gov/sites/default/files/2017-11/documents/eqasop-fieldcalibrat3.pdf.

USEPA. 2017b. Region 1. Low Stress (low-flow) Purging and Sampling Procedure for the Collection of

Groundwater Samples from Monitoring Wells (EQASOP-GW4). September 19. Available online at:

https://www.epa.gov/sites/production/files/2017-10/documents/eqasop-gw4.pdf.

USEPA. 2018. Region 1 – EPA New England Environmental Data Review Program Guidance. June. Available online at: https://www.epa.gov/sites/production/files/2018-06/documents/r1-dr-program-guidance-june-

2018.pdf.

https://www.epa.gov/sites/production/files/2018-06/documents/r1-dr-program-guidance-june-2018.pdf https://www.epa.gov/sites/production/files/2018-06/documents/r1-dr-program-guidance-june-2018.pdf

Tables

Table 1 Sample Analysis Methods, Containers, Holding Times, and Preservatives Former Sudbury Training Annex Sudbury, Massachusetts

Parameter Analysis

Method1 Sample Container2 Preservative Holding Time

VOCs SW8260C 3 x 40 mL vials with

Teflon septa screw caps

Hydrochloric acid (HCl) to pH < 2 (no headspace);

4 ± 2°C 14 days

Pesticides SW8081B 2 x 1-liter amber glass 4 ± 2°C 7 days to extract;

40 days to analyze

COD E410.4 1 x 500 mL amber glass Sulfuric acid (H2SO4) to pH < 2;

4 ± 2°C 28 days

Cyanide SW9012B 1 x 250 mL HDPE Sodium hydroxide (NaOH) to pH > 12;

4 ± 2°C

14 days

Notes:

2 Additional sample containers/volume are required for matrix quality control samples.

Acronyms and Abbreviations:

°C = degrees Celsius COD = chemical oxygen demand

HDPE = high-density polyethylene mL = milliliter USEPA = United States Environmental Protection Agency

VOC = volatile organic compound

1 “Methods for Chemical Analysis of Water and Wastes,” Cincinnati, OH. July 2014, EPA 600-4-79-020. “Test Methods for Evaluating Solid Waste, Physical and Chemical Methods,” USEPA SW-846, 5th Edition.

Table 2 AOC A7 Groundwater Monitoring Locations Former Sudbury Training Annex Sudbury, Massachusetts

Elevation (ft NAVD88)

Ground Surface

Top of PVC Riser

Top of Well Screen

Bottom of Well Screen

Monitoring Wells

JO-A07-M61 N/A - gauged only 2977583.8535 660885.7957 5 1.0 - 6.0 180.43 180.10 179.10 174.10

OHM-A7-08 Biennial 2977358.2301 661043.0108 15 20.6 - 35.6 216.65 219.04 198.44 183.44

OHM-A7-09 N/A - gauged only 2977602.8875 661129.0809 8 6.9 - 14.9 183.41 185.41 178.51 170.51

OHM-A7-10 N/A - gauged only 2977679.1663 661269.0955 8 3.6 - 11.6 178.84 180.40 176.80 168.80

OHM-A7-11 N/A - gauged only 2977674.7354 661261.5028 10 20.9 - 30.9 179.04 180.93 160.03 150.03

OHM-A7-12 N/A - gauged only 2977663.4705 661392.2324 15 5.8 - 20.8 184.29 186.29 180.49 165.49

OHM-A7-45 N/A - gauged only 2977318.0231 660886.6097 15 7.2 - 22.2 207.24 209.21 202.01 187.01

OHM-A7-46 N/A - gauged only 2977307.2923 660974.2810 6.5 13.1 - 19.6 215.25 217.07 203.97 197.47

OHM-A7-51 N/A - gauged only 2977531.2001 660976.5204 15 7.6 - 22.6 186.60 188.42 180.82 165.82

OHM-A7-52 N/A - gauged only 2977492.1060 660885.5278 15 6.7 - 21.7 186.66 187.31 180.61 165.61

SUD-A07-014 Biennial 2977122.6180 661162.4454 10 12.0 - 22.0 222.56 225.57 213.57 203.57

SUD-A07-065 Biennial 2977656.2636 660955.3573 5 4.5 - 9.5 177.79 177.82 173.32 168.32

SUDA7-19-01 Annual 2977653.700 661047.7000 10 2.0 - 10.0 181.30 180.79 179.30 171.30

Staff Gauges

Northern Staff Gauge N/A - gauged only 2977741.548 661027.2003 N/A N/A 176.54 179.52(1) N/A N/A

Eastern Staff Gauge N/A - gauged only 2977696.924 661513.0199 N/A N/A 175.64 181.99(2) N/A N/A

Notes:

Horizontal datum is Massachusetts State Plane Coordinate System (Mainland 2001), North America Datum of 1983 (NAD83).

Vertical elevation datum is National Geodetic Vertical Datum of 1929 (NGVD29) converted to North American Vertical Datum of 1988 (NAVD88) in 2019.

Depth and screened interval are in feet below the top of casing (e.g., the top of the PVC riser) based on the November 2006 survey.

(1) Surveyed elevation of nail in the tree.

(2) Surveyed elevation of 180-foot mark on the Eastern Staff Gauge.

Acronyms and Abbreviations:

AOC = Area of Contamination ft = feet

N/A = not applicable

PVC = polyvinyl chloride TOC = top of casing

Location Current

Sampling Frequency

Northing (ft NAD83)

Easting (ft NAD83)

Screen Length

(ft)

Screened Interval Depth (ft below TOC)

Table 3 AOC A7 Groundwater Elevations, Fall 2023 Former Sudbury Training Annex Sudbury, Massachusetts

Location Date Depth to Water

(ft bmp)

Measuring Point Elevation

(ft NAVD88)

Water Table Elevation

(ft NAVD88)

Monitoring Wells

JO-A07-M61 11/08/2023 1.97 180.10 178.13

OHM-A7-08 11/08/2023 24.01 219.04 195.03

OHM-A7-09 11/08/2023 7.66 185.41 177.75

OHM-A7-10 11/08/2023 3.31 180.40 177.09

OHM-A7-11 11/08/2023 1.13 180.93 179.80

OHM-A7-12 11/08/2023 8.58 186.29 177.71

OHM-A7-45 11/08/2023 13.18 209.21 196.03

OHM-A7-46 11/08/2023 15.33 217.07 201.74

OHM-A7-51 11/08/2023 8.26 188.42 180.16

OHM-A7-52 11/08/2023 4.08 187.31 183.23

SUD-A07-014 11/08/2023 7.58 225.57 217.99

SUD-A07-065 11/08/2023 1.91 177.82 175.91

SUDA7-19-01 11/08/2023 4.51 180.79 176.28

Staff Gauges Northern Staff Gauge 11/08/2023 6.25 179.52(1) 173.27

Eastern Staff Gauge 11/08/2023 5.29 181.99(2) 176.70

Notes:

(1) Surveyed elevation of nail in the tree.

(2) Surveyed elevation of 180-foot mark on the Eastern Staff Gauge.

Acronyms and Abbreviations:

AOC = Area of Contamination bmp = below measuring point ft = feet

Vertical elevation datum is National Geodetic Vertical Datum of 1929 (NGVD29) converted to North American Vertical Datum of 1988 (NAVD88) in 2019.

Table 4 AOC A7 Groundwater Analytical Results, Fall 2023 Former Sudbury Training Annex Sudbury, Massachusetts

Location

Sample ID

Date

Analyte/Method Unit MCP GW-1 MCP GW-3

Volatile Organic Compounds 1,1,1,2-Tetrachloroethane µg/L 5.0 50,000 1 U 1 U 1,1,1-Trichloroethane µg/L 200 20,000 0.5 U 0.5 U 1,1,2,2-Tetrachloroethane µg/L 2.0 50,000 1 U 1 U 1,1,2-Trichloroethane µg/L 5.0 50,000 1 U 1 U 1,1-Dichloroethane µg/L 70 20,000 1 U 1 U 1,1-Dichloroethene µg/L 7.0 30,000 1 U 1 U 1,1-Dichloropropene µg/L -- -- 1 U 1 U 1,2,3-Trichlorobenzene µg/L -- -- 2 U 2 U 1,2,3-Trichloropropane µg/L -- -- 1 U 1 U 1,2,4-Trichlorobenzene µg/L 70 50,000 2 U 2 U 1,2,4-Trimethylbenzene µg/L -- -- 1 U 1 U 1,2-Dibromo-3-chloropropane µg/L -- -- 5 U 5 U 1,2-Dibromoethane (EDB) µg/L 0.02 50,000 1 U 1 U 1,2-Dichlorobenzene µg/L -- -- 1 UJ 1 UJ 1,2-Dichloroethane µg/L 5.0 20,000 1 U 1 U 1,2-Dichloroethene µg/L -- -- 1 U 1 U 1,2-Dichloropropane µg/L 5.0 50,000 0.5 U 0.5 U 1,3,5-Trimethylbenzene µg/L -- -- 1 U 1 U 1,3-Dichlorobenzene µg/L 100 50,000 1 U 1 U 1,3-Dichloropropane µg/L -- -- 1 U 1 U 1,4-Dichlorobenzene µg/L 5.0 8,000 1 U 1 U 2,2-Dichloropropane µg/L -- -- 1 U 1 U 2-Butanone (MEK) µg/L 4,000 50,000 20 U 20 U 2-Chlorotoluene µg/L -- -- 0.5 U 0.5 U 2-Hexanone µg/L -- -- 10 U 10 U 4-Chlorotoluene µg/L -- -- 1 U 1 U 4-Methyl-2-pentanone (MIBK) µg/L 350 50,000 10 U 10 U Acetone µg/L 6,300 50,000 10 U 10 U Benzene µg/L 5.0 10,000 1 U 1 U Bromobenzene µg/L -- -- 0.5 U 0.5 U Bromochloromethane µg/L -- -- 1 U 1 U Bromodichloromethane µg/L -- -- 1 U 1 U Bromoform µg/L 4.0 50,000 2 U 2 U Bromomethane µg/L 10 800 10 UJ 10 UJ Carbon disulfide µg/L -- -- 1 U 1 U Carbon Tetrachloride µg/L 5.0 5,000 1 U 1 U Chlorobenzene µg/L 100 1,000 0.5 U 0.5 U Chloroethane µg/L -- -- 10 UJ 10 UJ Chloroform µg/L 70 20,000 1 U 1 U Chloromethane µg/L -- -- 2 U 2 U cis-1,2-Dichloroethene µg/L 70 50,000 1 U 1 U cis-1,3-Dichloropropene µg/L 0.40 200 1 U 1 U Cumene µg/L -- -- 1 U 1 U Dibromochloromethane µg/L 2.0 50,000 1 U 1 U Dibromomethane µg/L -- -- 1 U 1 U Dichlorodifluoromethane µg/L -- -- 1 U 1 U Ethylbenzene µg/L 700 5,000 0.5 U 0.5 U Hexachlorobutadiene µg/L 0.6 3,000 1 U 1 U m,p-Xylene µg/L 10,000 5,000 1 U 1 U Methyl tert-butyl ether (MTBE) µg/L 70 50,000 2 U 2 U Methylene chloride µg/L -- -- 10 U 10 U n-Butylbenzene µg/L -- -- 2 U 2 U n-Propylbenzene µg/L -- -- 1 U 1 U Naphthalene µg/L 140 20,000 5 U 5 U o-Xylene µg/L 10,000 5,000 1 U 1 U p-Cymene (p-Isopropyltoluene) µg/L -- -- 1 U 1 U sec-Butylbenzene µg/L -- -- 2 U 2 U Styrene µg/L 100 6,000 1 U 1 U tert-Butylbenzene µg/L -- -- 1 U 1 U Tetrachloroethene (PCE) µg/L 5.0 30,000 1 U 1 U Toluene µg/L 1,000 40,000 1 U 1 U trans-1,2-Dichloroethene µg/L 100 5,000 1 U 1 U trans-1,3-Dichloropropene µg/L -- -- 1 U 1 U Trichloroethene (TCE) µg/L 5.0 5,000 0.5 U 0.5 U Trichlorofluoromethane µg/L -- -- 1 U 1 U Vinyl acetate µg/L -- -- 2 U 2 U Vinyl chloride µg/L 2.0 50,000 1 U 1 U Xylenes, Total µg/L -- -- 1 U 1 U

11/8/2023

SUDA7-19-01

SUDA7-19-01-FAL23 SUD-DUP01-FAL23

11/8/2023

Table 4 AOC A7 Groundwater Analytical Results, Fall 2023 Former Sudbury Training Annex Sudbury, Massachusetts

Location

Sample ID

Date

Analyte/Method Unit MCP GW-1 MCP GW-3

11/8/2023

SUDA7-19-01

SUDA7-19-01-FAL23 SUD-DUP01-FAL23

11/8/2023

Pesticides 4,4'-DDD (4,4'-Dichlorodiphenyldichloroethane) µg/L 0.20 50 0.0042 UJ 0.0042 UJ 4,4'-DDE (4,4'-Dichlorodiphenyldichloroethylene) µg/L 0.05 400 0.0042 UJ 0.0042 UJ 4,4'-DDT (4,4'-Dichlorodiphenyltrichloroethane) µg/L 0.30 1.0 0.0042 U 0.0042 UJ Aldrin µg/L 0.50 30 0.0042 UJ 0.0042 UJ alpha-BHC (alpha-Hexachlorocyclohexane) µg/L -- -- 0.0042 UJ 0.0042 UJ alpha-Endosulfan µg/L 10 2.0 0.0042 UJ 0.0042 UJ beta-BHC (beta-Hexachlorocyclohexane) µg/L -- -- 0.0042 U 0.0042 UJ beta-Endosulfan µg/L 10 2.0 0.0042 U 0.0042 UJ Chlordane µg/L 2.0 2.0 0.42 U 0.42 UJ delta-BHC (delta-Hexachlorocyclohexane) µg/L -- -- 0.0042 U 0.0042 UJ Dieldrin µg/L 0.10 0.5 0.0042 UJ 0.0042 UJ Endosulfan sulfate µg/L -- -- 0.0042 UJ 0.0042 UJ Endrin µg/L 2.0 5.0 0.0042 UJ 0.0042 UJ Endrin aldehyde µg/L -- -- 0.017 U 0.017 UJ Endrin ketone µg/L -- -- 0.017 U 0.017 UJ gamma-BHC (Lindane) µg/L 0.20 4.0 0.0042 UJ 0.0042 UJ Heptachlor µg/L 0.40 1.0 0.0042 UJ 0.0042 UJ Heptachlor epoxide µg/L 0.20 2.0 0.0042 UJ 0.0042 UJ Methoxychlor µg/L 40 10 0.0042 U 0.0042 UJ Toxaphene µg/L -- -- 0.84 U 0.85 UJ Other Chemical Oxygen Demand mg/L -- -- 20 U 20 U Cyanide, Total mg/L 0.20 0.030 0.0025 J 0.005 UJ Field Parameters pH SU -- -- 5.02 --- Specific Conductance mS/cm -- -- 0.04 --- Turbidity NTU -- -- 0.64 --- Dissolved Oxygen mg/L -- -- 1.49 --- Temperature ° C -- -- 12.6 --- ORP mV -- -- 220 ---

Notes:

1. -- = not available/not analyzed

Abbreviations:

°C = degrees Celsius µg/L = microgram per liter

AOC = Area of Contamination

FD = field duplicate

J = estimated concentration

MCP GW = Massachusetts Contingency Plan Method 1 groundwater standard mg/L = milligram per liter

UJ = The analyte was not detected above the limit of detection. However, the associated numerical value is approximate.

2. Target compounds in this table are compounds that have been detected above MCP GW-1 standards historically; no cleanup concentration requirements are stipulated for the site and MCP GW standards are included for comparative purposes.

U = The analyte was not detected above the limit of detection.

Figures

Former Sudbury Training Annex

Former Sudbury Training Annex

AOC P31 & AOC P58

AOC A7

Willis Lake

Puffer Pond

Maynard

Assabet River

Lake Boon

White Pond

Pine Lake

Pine Rest

Sudbury

Bru en

Rd

State R d

Sudbury Rd

Waltham St

M aynard R d

D ut to n

R d

P arker S t

Main St

Great Rd

Hudson Rd

Moore Rd

F or t M ea do w

B ro ok

Taylor B rook

A ssabet

R iver

Elizabeth Brook

Hop B ro ok

Assabet River

R un B rook

Eliz ab et h

Bro ok Legend

Former Sudbury Training Annex

Area of Contamination (AOC)

Area of Contamination Perimeter

Major Road

Federal Emergency Management Agency (FEMA) Parcel

Assabet River National Wildlife Refuge Boundary

River/Stream

Water Body

2023 Annual Long-Term Monitoring and Maintenance Report Area of Contamination A7

Former Sudbury Training Annex Sudbury, Massachusetts

Site Location Former Sudbury Training Annex

Figure

0 0.5 1

Miles

Massachusetts

Former Sudbury Training Annex

Aerial Source:

ESRI, ArcGIS Online, Aerial Imagery

³

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

#0

#0

!A

!A

!A

!A

Assabet River

Patro l R oad

Assabet Road Trail

Gate

Gate

Replicated Wetland

A7-3

A7-2

A7-1

A7-4

OHM-A7-12

OHM-A7-10

OHM-A7-52

OHM-A7-45

OHM-A7-11

OHM-A7-09

OHM-A7-51

OHM-A7-08

OHM-A7-46

JO-A07-M61

SUD-A07-014

SUD-A07-065

Eastern Staff Gauge

Northern Staff Gauge

SUDA7-19-01

Lab Waste Disposal Area

Lab Waste Disposal Area

AOC A7

Legend

Area of Contamination (AOC)

Stump Pile Area

AAAAAA

AAAAAA

AAAAAA

AAAAAA

Rip Rap

Lab Waste Disposal Area

Approximate Areas of Soil Removal

&< LTM Sample Well*

&< LTM Well - Gauge Only

#0 Staff Gauge

!A Gas Vent

[ Fence

Road

Topographic Contour (ft AMSL)

File: Devens_AR2023_SUD.aprx

2023 Annual Long-Term Monitoring and Maintenance Report Area of Contamination A7

Former Sudbury Training Annex Sudbury, Massachusetts

Site Layout

AOC A7

Figure

0 100 200

Feet

³

Aerial Source:

Google Earth, 2018

P at h:

T

E

N V

\D ev en s_

R F

TA

\S ee d_

Ta sk

_O rd er \M

X D s\ A

R

S U

D \2

4-

-0

5\ D ev en s_ A

R

_S

U D

.a pr x U se r

: m si

D at e:

/5

/2

Notes:

ft AMSL = feet above mean sea level LTM = long-term monitoring

* Annual sampling is conducted at well SUDA7-19-01. Biennial sampling is conducted at wells OHM-A7-08, SUD-A07-014, and SUD-A07-065 in even years (2022, 2024, 2026, etc.). Only SUDA7-19-01 was sampled in 2023.

Lake Boon

Lake Boon

S udbury R oad

AOC P31

AOC P58

Legend

Area of Concern

Former Sudbury Training Annex

Road

Trail

Surface Water Body

File: Devens_AR2023_SUD.aprx

2023 Annual Long-Term Monitoring and Maintenance Report Area of Contamination A7

Former Sudbury Training Annex Sudbury, Massachusetts

Site Layout AOC P31 and AOC P58

Figure

0 100 200

Feet

Aerial Source:

ESRI, ArcGIS Online, Aerial Imagery

Aerial Source:

ESRI, ArcGIS Online, Aerial Imagery

³ P at h:

T

E N

V \D ev en s_ R

F

TA

\S ee d_ Ta sk _O rd er

\M X

D s\

A R

S

U D

\2

4-

-0 5\

D ev en s_

A R

_S U

D .a pr x

U se r : m si

D at e:

/5 /2

Note: Figure base map, including the trail and surface water bodiies are from the Town of Stow WebGIS database (https://experience.arcgis.com/experience/8fa6b097404d4de286f4fc6c2d4 2fa1f/page/Public-WebGIS/)

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAAA

#0

#0

!A

!A

!A

!A

Assabet River

Patro l R oad

Assabet Road Trail

Gate

Gate

Replicated Wetland

Lab Waste Disposal Area

Lab Waste Disposal Area

SUD-A07-014

OHM-A7-46

OHM-A7-08

OHM-A7-51

OHM-A7-09SUD-A07-065

OHM-A7-11

OHM-A7-45

OHM-A7-52

JO-A07-M61

OHM-A7-10

OHM-A7-12

Eastern Staff Gauge

Northern Staff Gauge

SUDA7-19-01

A7-4

A7-1

A7-2

A7-3

(217.99)

(201.74)

(195.03)

(180.16)

(177.75) (175.91)

(179.80**)

(196.03)

(183.23)

(178.13)

(177.09)

(177.71) (176.70)

(173.27)

(176.28)

210215

AOC A7

Legend

Area of Contamination (AOC)

Stump Pile Area

AAAAAA

AAAAAA

AAAAAA

Rip Rap

Lab Waste Disposal Area

Approximate Areas of Soil Removal

&< LTM Sample Well*

&< LTM…