FINAL 

Site Inspection Report 

1109th TASMG-Groton 

Groton, Connecticut 

Site Inspection for Perfluorooctanoic acid (PFOA),

Perfluorooctanesulfonic acid (PFOS), Perfluorohexanesulfonic

acid (PFHxS), Perfluorononanoic acid (PFNA),

Hexafluoropropylene oxide dimer acid (HFPO-DA), and

Perfluorobutanesulfonic acid (PFBS) at ARNG Installations,

Nationwide 

July 2023 

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
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Table of Contents

Executive Summary ................................................................................................................ ES-1

1. Introduction .................................................................................................................... 1-1

1.1 Project Authorization............................................................................................... 1-1

1.2 SI Purpose .............................................................................................................. 1-1

2. Facility Background........................................................................................................ 2-1

2.1 Facility Location and Description ............................................................................ 2-1

2.2 Facility Environmental Setting................................................................................. 2-1

2.2.1 Geology ........................................................................................................ 2-1

2.2.2 Hydrogeology ............................................................................................... 2-2

2.2.3 Hydrology ..................................................................................................... 2-2

2.2.4 Climate ......................................................................................................... 2-3

2.2.5 Current and Future Land Use....................................................................... 2-3

2.2.6 Sensitive Habitat and Threatened/ Endangered Species............................. 2-3

2.3 History of PFAS Use ............................................................................................... 2-4

3. Summary of Areas of Interest......................................................................................... 3-1

3.1 AOI 1 Building 320 – Main Hangar ......................................................................... 3-1

3.2 AOI 2 Building 323 – Engine Shop ......................................................................... 3-1

3.3 AOI 3 Building 325 – State Equipment Storage Building........................................ 3-2

3.4 Adjacent Sources.................................................................................................... 3-2

3.4.1 Groton-New London Airport.......................................................................... 3-2

3.4.2 Groton-New London Airport Fire Department............................................... 3-3

4. Project Data Quality Objectives ..................................................................................... 4-1

4.1 Problem Statement ................................................................................................. 4-1

4.2 Information Inputs ................................................................................................... 4-1

4.3 Study Boundaries ................................................................................................... 4-1

4.4 Analytical Approach ................................................................................................ 4-1

4.5 Data Usability Assessment ..................................................................................... 4-1

5. Site Inspection Activities................................................................................................. 5-1

5.1 Pre-Investigation Activities...................................................................................... 5-1

5.1.1 Technical Project Planning ........................................................................... 5-1

5.1.2 Utility Clearance ........................................................................................... 5-2

5.1.3 Source Water and Sampling Equipment Acceptability.................................. 5-2

5.2 Soil Borings and Soil Sampling............................................................................... 5-2

5.3 Temporary Well Installation and Groundwater Grab Sampling ............................... 5-3

5.4 Synoptic Water Level Measurements ..................................................................... 5-4

5.5 Surveying................................................................................................................ 5-4

5.6 Investigation-Derived Waste ................................................................................... 5-4

5.7 Laboratory Analytical Methods................................................................................ 5-5

5.8 Deviations from SI QAPP Addendum ..................................................................... 5-5

6. Site Inspection Results................................................................................................... 6-1

6.1 Screening Levels .................................................................................................... 6-1

6.2 Soil Physicochemical Analyses............................................................................... 6-2

6.3 AOI 1....................................................................................................................... 6-2

6.3.1 AOI 1 Soil Analytical Results ........................................................................ 6-2
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6.3.2 AOI 1 Groundwater Analytical Results .........................................................6-2

6.3.3 AOI 1 Conclusions........................................................................................6-3

6.4 AOI 2.......................................................................................................................6-3

6.4.1 AOI 2 Soil Analytical Results ........................................................................6-3

6.4.2 AOI 2 Groundwater Analytical Results .........................................................6-3

6.4.3 AOI 2 Conclusions........................................................................................6-4

6.5 AOI 3.......................................................................................................................6-4

6.5.1 AOI 3 Soil Analytical Results ........................................................................6-4

6.5.2 AOI 3 Groundwater Analytical Results .........................................................6-4

6.5.3 AOI 3 Conclusions........................................................................................6-4

7. Exposure Pathways .......................................................................................................7-1

7.1 Soil Exposure Pathway...........................................................................................7-1

7.1.1 AOI 1 ............................................................................................................7-1

7.1.2 AOI 2 ............................................................................................................7-2

7.1.3 AOI 3 ............................................................................................................7-2

7.2 Groundwater Exposure Pathway ............................................................................7-3

7.2.1 AOI 1 ............................................................................................................7-3

7.2.2 AOI 2 ............................................................................................................7-3

7.2.3 AOI 3 ............................................................................................................7-3

7.3 Surface Water and Sediment Exposure Pathway...................................................7-3

7.3.1 AOI 1 ............................................................................................................7-3

7.3.2 AOI 2 ............................................................................................................7-4

7.3.3 AOI 3 ............................................................................................................7-4

8. Summary and Outcome .................................................................................................8-1

8.1 SI Activities .............................................................................................................8-1

8.2 Outcome .................................................................................................................8-1

9. References.....................................................................................................................9-1
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Appendices

Appendix A Data Usability Assessment and Validation Reports

Appendix B Field Documentation

B1. Log of Daily Notice of Field Activities

B2. Sampling Forms

B3. Survey Data

B4. Investigation-Derived Waste Polygons

Appendix C Photographic Log

Appendix D TPP Meeting Minutes

Appendix E Boring Logs

Appendix F Analytical Results

Appendix G Laboratory Reports

Figures

Figure 2-1 Facility Location

Figure 2-2 Facility Topography

Figure 2-3 Groundwater Features

Figure 2-4 Groundwater Elevations, May, 2022

Figure 2-5 Surface Water Features

Figure 3-1 Areas of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOA Detections in Soil

Figure 6-2 PFOS Detections in Soil

Figure 6-3 PFBS Detections in Soil

Figure 6-4 PFHxS Detections in Soil

Figure 6-5 PFNA Detections in Soil

Figure 6-6 PFOA, PFOS, and PFBS Detections in Groundwater

Figure 6-7 PFHxS and PFNA Detections in Groundwater

Figure 7-1 Conceptual Site Model, AOI 1

Tables

Table ES-1 Screening Levels (Soil and Groundwater)

Table ES-2 Summary of Site Inspection Findings and Recommendations

Table 5-1 Site Inspection Samples by Medium

Table 5-2 Soil Boring Depths, Temporary Well Screen Intervals, and Groundwater 

Elevations

Table 6-1 Screening Levels (Soil and Groundwater)

Table 6-2 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Surface Soil

Table 6-3 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Table 6-4 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater

Table 8-1 Summary of Site Inspection Findings and Recommendations
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Acronyms and Abbreviations

% percent

°C degrees Celsius

°F degrees Fahrenheit

μg/kg micrograms per kilogram

AECOM AECOM Technical Services, Inc.

AFFF aqueous film-forming foam

amsl above mean sea level

AOI Area of Interest

ARFF Aircraft rescue and firefighting 

ARNG Army National Guard

bgs below ground surface 

CAA Connecticut Airport Authority

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CoC chain of custody

CSM conceptual site model

CTARNG Connecticut Army National Guard

CTDEEP Connecticut Department of Energy and Environmental Protection

DA Department of the Army

DoD Department of Defense

DPT direct push technology

DQO data quality objective

DUA data usability assessment

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

FedEx Federal Express

gpm gallons per minute

GPS Global positioning system

GPRS Ground Penetrating Radar Systems

HDPE high-density polyethylene 

HFPO-DA hexafluoropropylene oxide dimer acid

IDW investigation-derived waste

ITRC Interstate Technology Regulatory Council

LC/MS/MS liquid chromatography with tandem mass spectrometry

MIL-SPEC military specification

NELAP National Environmental Laboratory Accreditation Program

ng/L nanograms per liter

NOAA National Oceanic and Atmospheric Administration

OSD Office of the Secretary of Defense

OWS oil-water separator

PA Preliminary Assessment

PFAS per- and polyfluoroalkyl substances

PFBS perfluorobutanesulfonic acid

PFHxS perfluorohexanesulfonic acid
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PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PID photoionization detector

PQAPP Programmatic UFP-QAPP

PVC polyvinyl chloride

QA quality assurance

QAPP Quality Assurance Project Plan

QC quality control

QSM Quality Systems Manual

SI Site Inspection

SL screening level

SOP standard operating procedure

TASMG Theatre Aviation Sustainment Management Group

TOC total organic carbon

TPP Technical Project Planning

UFP Uniform Federal Policy

US United States

USACE United States Army Corps of Engineers

USCS Unified Soil Classification System

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service

WPCF Water Pollution Control Facility
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Executive Summary

The Army National Guard (ARNG) G-9 is performing Preliminary Assessments (PAs) and Site 

Inspections (SIs) on the current or potential historical use of per- and polyfluoroalkyl substances 

(PFAS) with a focus on the six compounds presented in the memorandum from the Office of the 

Secretary of Defense (OSD) dated 6 July 2022 (Assistant Secretary of Defense, 2022). The six 

compounds listed in the OSD memorandum include perfluorooctanesulfonic acid (PFOS), 

perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid

(PFHxS), hexafluoropropylene oxide dimer acid (HFPO-DA)1, and perfluorobutanesulfonic acid 

(PFBS). These compounds are collectively referred to as “relevant compounds” throughout the 

document, and the applicable screening levels (SLs) are provided in Table ES-1. 

The PA identified three Areas of Interest (AOIs) where PFAS-containing materials may have been 

used, stored, disposed, or released historically (see Table ES-2 for AOI locations). The objective 

of the SI is to identify whether there has been a release to the environment from the AOIs identified 

in the PA and determine whether further investigation is warranted, a removal action is required 

to address immediate threats, or no further action is required based on SLs for relevant 

compounds. This SI was completed at the 1109th Theatre Aviation Sustainment Management 

Group (TASMG-Groton) in Groton, Connecticut and determined further evaluation under the 

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) is 

warranted for AOI 1, AOI 2, and AOI 3. TASMG-Groton will also be referred to as the “facility” 

throughout this document.

The facility is located on the Groton-New London Airport property, which is situated on a peninsula 

between the Poquonnock River, Baker Cove, Birch Plain Creek, and the Long Island Sound. 

TASMG-Groton comprises several buildings, including multiple hangars, office spaces, material 

storage areas, and a flight test ramp. The facility provides testing, repairs, and maintenance for 

Connecticut Army National Guard equipment and aircrafts. The facility also provides services to 

aircraft at the Groton-New London Airport and services ARNG operations in 14 northeastern 

states and the District of Columbia.

The PA identified three AOIs for investigation during the SI phase. SI sampling results from the 

three AOIs were compared to OSD SLs. Table ES-2 summarizes the SI results for each AOI.

Based on the results of this SI, further evaluation under CERCLA is warranted in a Remedial 

Investigation for AOI 1, AOI 2, and AOI 3.

1 Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to as GenX) was not 

included as an analyte at the time of this SI. Based on the conceptual site model (CSM) developed during the PA and revised based 

on SI findings, the presence of HFPO-DA is not anticipated at the facility because HFPO-DA is generally not a component of military 

specification (MIL-SPEC) aqueous film forming foam (AFFF) and based on its history including distribution limitations that restricted 

use of GenX, it is generally not a component of other products the military used. In addition, it is unlikely that GenX would be an 

individual chemical of concern in the absence of other PFAS.
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Table ES-1: Screening Levels (Soil and Groundwater) 

Analyteb

Residential

(Soil)

(μg/kg)a 

0-2 feet bgs

Industrial/ Commercial 

Composite Worker

(Soil)

(μg/kg)a 

2-15 feet bgs

Tap Water

(Groundwater) 

(ng/L)a

PFOA 19 250 6 

PFOS 13 160 4 

PFBS 1,900 25,000 601 

PFHxS 130 1,600 39

PFNA 19 250 6 

Notes:

bgs = below ground surface; μg/kg = micrograms per kilogram; ng/L = nanograms per liter

a.) Assistant Secretary of Defense, 2022. Risk Based Screening Levels in Groundwater and Soil using United States Environmental Protection 

Agency’s (USEPA’s) Regional Screening Level Calculator. Hazard Quotient (HQ) = 0.1. 6 July 2022. 

b.) Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to as GenX) was not included 

as an analyte at the time of this SI. Based on the CSM developed during the PA and revised based on SI findings, the presence of HFPODA is not anticipated at the facility because HFPO-DA is generally not a component of MIL-SPEC AFFF and based on its history including 

distribution limitations that restricted use of GenX, it is generally not a component of other products the military used. In addition, it is 

unlikely that GenX would be an individual chemical of concern in the absence of other PFAS. 

Table ES-2: Summary of Site Inspection Findings and Recommendations

AOI Potential 

Release Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater –

Facility 

Boundary

Future Action

1 Building 320 – 

Main Hangar N/A Proceed to RI 

2 Building 323 – 

Engine Shop Proceed to RI 

3

Building 325 – 

State Equipment 

Storage Building

N/A Proceed to RI

Legend:

N/A = not applicable 

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected
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1. Introduction

1.1 Project Authorization

The Army National Guard (ARNG) G-9 is the lead agency in performing Preliminary Assessments 

(PAs) and Site Inspections (SIs) on the current or potential historical use of per- and 

polyfluoroalkyl substances (PFAS) with a focus on the six compounds presented in the 

memorandum from the Office of the Secretary of Defense (OSD) dated 6 July 2022 (Assistant 

Secretary of Defense, 2022). The six compounds listed in the OSD memorandum will be referred 

to as “relevant compounds” throughout this document and include perfluorooctanoic acid (PFOA), 

perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic 

acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA)1, and perfluorobutanesulfonic 

acid (PFBS) at ARNG facilities nationwide. The ARNG performed this SI at the 1109th Theatre 

Aviation Sustainment Management Group (TASMG-Groton) in Groton, Connecticut. TASMGGroton will also be referred to as the “facility” throughout this document.

The SI project elements were performed in compliance with Comprehensive Environmental 

Response, Compensation, and Liability Act (CERCLA; United States [US] Environmental 

Protection Agency [USEPA], 1980), as amended, the National Oil and Hazardous Substances 

Pollution Contingency Plan (40 Code of Federal Regulations Part 300; USEPA, 1994), and in 

compliance with US Department of the Army (DA) requirements and guidance for field 

investigations.

1.2 SI Purpose

A PA was performed at TASMG-Groton (AECOM Technical Services, Inc. [AECOM], 2020) that

identified three Areas of Interest (AOIs) where PFAS-containing materials may have been used, 

stored, disposed, or released historically. The objective of the SI is to identify whether there has 

been a release to the environment from the AOIs identified in the PA and determine whether 

further investigation is warranted, a removal action is required to address immediate threats, or 

no further action is required based on screening levels (SLs) for the relevant compounds.

1 Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to as GenX) was not 

included as an analyte at the time of this SI. Based on the conceptual site model (CSM) developed during the PA and revised based 

on SI findings, the presence of HFPO-DA is not anticipated at the facility because HFPO-DA is generally not a component of military 

specification (MIL-SPEC) aqueous film forming foam (AFFF) and based on its history including distribution limitations that restricted 

use of GenX, it is generally not a component of other products the military used. In addition, it is unlikely that GenX would be an 

individual chemical of concern in the absence of other PFAS.
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2. Facility Background

2.1 Facility Location and Description

TASMG-Groton is located in the city of Groton, in New London County, Connecticut (Figure 2-1). 

The facility is located on the Groton-New London Airport property, which is situated on a peninsula 

between the Poquonnock River, Baker Cove, Birch Plain Creek, and the Long Island Sound. 

TASMG-Groton comprises several buildings, including multiple hangars, office spaces, material 

storage areas, and a flight test ramp. The facility provides testing, repairs, and maintenance for 

Connecticut ARNG (CTARNG) equipment and aircrafts. The facility also provides services to 

aircraft at the Groton-New London Airport and services ARNG operations in 14 northeastern 

states and the District of Columbia.

TASMG-Groton is located on state-owned property. The CTARNG established its presence on the 

property in the 1950s. The facility transitioned from an Aviation Classification and Repair Depot 

to the TASMG-Groton in 2012 and expanded upon its mission capabilities. TASMG-Groton 

occupies approximately 16 acres of the northwest corner of the airport. There are two guarded 

entranceways for vehicle traffic to access the facility. A chain link fence provides security along 

the north, east, and south sides of the facility. The southwest corner is open to the Groton-New 

London Airport, which maintains its own security for the area (CTARNG, 2019). 

Groton-New London Airport was established in 1929; it was designated as a major training center 

for pilots and aircrews during World War II and was later transferred for operation to the Navy. 

The State of Connecticut resumed airport ownership and operations in 1949. In 1984, the airport 

was approved to operate commercial air service. The Connecticut Airport Authority (CAA) 

maintains the Groton-New London Airport.

2.2 Facility Environmental Setting

TASMG-Groton and the larger Groton-New London Airport are located on a peninsula bordered 

by the Poquonnock River to the east, Baker Cove to the west, and Long Island Sound to the 

south. Bluff Point and Bushy Point Beach form a breakwater-like barrier, separating the facility 

and airport property from Long Island Sound. Topography across the facility is generally flat, and 

topography across the larger airport area generally slopes radially away on the edges of the 

peninsula towards the surrounding water bodies (Figure 2-2). The facility is zoned for 

industrial/commercial use and is surrounded by properties zoned for commercial, industrial, and 

residential use (CTARNG, 2019).

2.2.1 Geology

The facility and surrounding airport property are underlain by the Wisconsinan-aged Poquonnock 

River deposits, which were the result of sediment-dammed lakes. These deposits are icemarginal, fluviodeltaic sediments within the Long Island Sound Basin and are composed of silt, 

sand, and gravel (Goldsmith, 1962; Stone et al., 2005). Glacial sediments in the area are 

measured at thicknesses between 50-100 feet (Stone et al., 2005; Thomas, 2008). The bedrock 

in the New London area comprises schists and gneisses. The bedrock is mostly light-gray to 

medium-gray metasedimentary and metaigneous aluminous, felsic intermediate, and mafic rocks 

of Proterozoic to Devonian age (Stone et al., 2005). The Proterozoic-age New London Gneiss 

directly underlies the facility (Rodgers, 1985). The bedrock geology is shown on Figure 2-3. 

Virtually all areas at the Groton-New London airport are underlain with artificial fill. Perimeter soils 

on the edge of the peninsula are tidal and inland wetlands (DeCarlo & Doll, Inc., 1996).
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Borings completed as a part of this SI were drilled to depths between 10 and 15 feet below ground 

surface (bgs). The geological data collected from the boreholes indicate that the dominant 

lithology of the unconsolidated material underlying the facility is comprised of fine- to coarsegrained, well-graded sand. Boring logs showed varying percentages of fines (silt) and gravel. 

Fines in subsurface soil ranged from trace amounts to 45 percent (%). Gravel was also observed 

in borings varying from 5% to 45%. The soils observed at the facility have a relatively high 

hydraulic conductivity, with well-graded sands having the highest conductivity. No impermeable 

material layers were observed in SI borings. These site observations are consistent with the 

expected subsurface material conditions.

2.2.2 Hydrogeology

The majority of the Connecticut coastline, including the city of Groton, lies within the Long Island 

Sound Basin. This basin is principally drained by the Long Island Sound. In the southeastern 

coastal river basins of Connecticut, groundwater is sourced from three types of aquifers: stratified 

drift, till, and bedrock. At the facility, a surficial, coarse-grained stratified drift aquifer serves as the 

primary water-bearing unit (Thomas et al., 1968; Thomas, 2008). Coarse-grained stratified drift 

aquifers have the potential to yield large quantities of water (i.e., >100 gallons per minute [gpm]) 

and are the most productive of the three aquifer types. Groundwater in bedrock may occur 

beneath the facility in areas where the rock is heavily fractured. Domestic wells screened in 

bedrock in the southeastern coastal river basins have historically produced up to 150 gpm 

(Thomas et al., 1968). The bedrock is directly overlain by the stratified drift units; therefore, there 

is no confining unit between the two aquifers.

The groundwater underlying TASMG-Groton and the larger surrounding airport property is 

designated as “class GB” by the Connecticut Department of Energy and Environmental Protection 

(CTDEEP), which indicates that the area has a long history of urban or industrial activity. Class 

GB groundwater is assumed to be degraded due to likely pollution sources, and it is presumed 

not to be suitable for human consumption without treatment (CAA, 2013). Due to the groundwater 

designation as class GB, the airport property including TASMG-Groton is supplied water drinking 

water by the Groton Utilities Water Operations. Groton Utilities Water Operations sources its water 

from a variety of groundwater wells and surface water reservoirs, some of which are located within 

4 miles north and upgradient of the facility. Groundwater features at the facility are shown on 

Figure 2-3. There are currently no potable water wells at the facility.

Depths to water measured in May 2022 during the SI ranged from 1.12 to 9.52 feet bgs.

Groundwater was shallowest at temporary well location TMG-01 near a stormwater outlet pipe 

discharge point. Groundwater elevation contours from the SI are presented on Figure 2-4 and 

indicate groundwater flow direction is generally to the southwest.

2.2.3 Hydrology

There are no delineated surface water bodies on the TASMG-Groton property; however, there are 

several surface water bodies immediately surrounding the property, and the airport lies on a 

coastal peninsula (Figure 2-5). The airport is located within the Southeast Costal Drainage Basin 

(CAA, 2013) and falls within the 100-year floodplain of the town of Groton. The area is subject to 

occasional flooding events during hurricanes and major nor’easters. During these events, 

floodwaters may extend onto areas surrounding the southern end of the airport runway and 

taxiway edges. During heavy rainfall events, localized flooding may also occur on the airplane 

parking ramps (CAA, 2013). An off-facility freshwater pond and forested wetland are present 

approximately 0.1 miles northeast of the facility main gate (Figure 2-5) (US Fish and Wildlife 

Service [USFWS], 2019).
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A small intermittent stream borders the northwest boundary of the CTARNG property and flows 

southwest into Birch Creek, which confluences with Birch Plain Creek before entering Baker 

Cove. TASMG-Groton generally drains via surface drainage from east to west. Stormwater runoff 

is also collected by catch basins throughout the facility. These catch basins channel flow west 

towards two main outlets near the northwestern portion of the facility that discharge into the small 

intermittent stream. Runoff entering the stream discharges to Birch Creek, then Baker Cove, and 

ultimately into the Long Island Sound, directly south of the Groton-New London Airport. Any runoff 

entering the stormwater drainage system or the intermittent stream has the potential of migrating 

to the Long Island Sound and wetlands associated with the intermittent stream (CTARNG, 2019).

Additionally, discharge from a stormwater outlet pipe located behind Building 322 flows across a 

stretch of grass prior to entering an area filled with cattails and other vegetation associated with 

wetlands. This area, located along the fence line behind the building, has not been delineated or 

identified by the USFWS as a wetland (CTARNG, 2019). Several oil-water separators (OWSs) 

are also positioned throughout the facility. The OWSs connect to the municipal sanitary sewer 

system, which ultimately discharges to the Groton Water Pollution Control Facility (WPCF). All 

OWSs are permitted with CTDEEP under the General Permit for the Discharge of Wastewaters 

Associated with Vehicle Maintenance activities #GVM-000179 (CTARNG, 2019). Trench drains 

located outside main hangar doors also discharge to the municipal sanitary sewer system.

2.2.4 Climate

Data from Groton-New London Airport, Connecticut, indicate that the annual average temperature 

between 1991 and 2020 in was 51.4 degrees Fahrenheit (oF) (National Oceanic and Atmospheric 

Administration [NOAA], 2022). The warmest months are July and August, with normal daily 

average temperatures of 72.3 oF and 71.5 oF, respectively. January is the coldest month, with an 

average temperature of 30.8 oF. Average annual precipitation at the airport measured from 1991 

to 2020 was 39.31 inches. Average monthly precipitation ranges from 2.20 inches in February to 

3.83 inches in September. The average annual snowfall is approximately 24 inches, with January 

and February usually experiencing the most snow (NOAA, 2022).

2.2.5 Current and Future Land Use

TASMG-Groton currently supports ARNG operations, including aviation, across northeastern 

states and the District of Columbia, as well as the Groton-New London Airport. Future land use at 

TASMG-Groton and the surrounding airport property is anticipated to remain the same.

2.2.6 Sensitive Habitat and Threatened/ Endangered Species 

The following birds, insects, mammals, plants, and reptiles are federally endangered, threatened, 

proposed, and/ or are listed as candidate species in New London County, Connecticut (USFWS, 

2022).

• Birds: Roseate tern, Sterna dougallii dougallii (endangered); Red knot, Calidris canutus rufa

(threatened); Piping Plover, Charadrius melodus (threatened)

• Insects: Monarch butterfly, Danaus plexippus (candidate)

• Mammals: Tricolored bat, Perimyotis subflavus (proposed endangered); Little brown bat, 

Myotis lucifugus (under review); Northern long-eared bat, Myotis septentrionalis

(threatened)
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• Flowering plants: Small whorled pogonia, Isotria medeoloides (threatened)

• Reptiles: Hawksbill Sea turtle, Eretmochelys imbricata (endangered); Leatherback sea 

turtle, Dermochelys coriacea (endangered)

2.3 History of PFAS Use

Three potential release areas were identified at the TASMG-Groton facility during the PA where 

AFFF may have been used or released historically (AECOM, 2020). At TASMG-Groton, the Main 

Hangar (Building 320) and the Engine Shop (Building 323) both contain fire suppression systems 

that utilize AFFF and may have released AFFF to soil and groundwater via system maintenance 

and discharges. Additionally, the State Equipment and Storage Building (Building 325) serves as 

a temporary storage area for fire suppression system discharge water that may contain residual 

AFFF and as a result may have released AFFF constituents to the surrounding surface. The three 

buildings were identified as AOIs for this SI. Descriptions of the AOIs are presented in Section 3.
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PROJECT Site Inspection at TASMG Groton, CT

11/28/2022

1:31,680 ­ Figure 2-1 PM CM 11/28/2022

12420 Milestone Center Drive

Germantown, MD 20876

Facility Location

Base Map: Sources: Esri, HERE, Garmin, USGS,

Intermap, INCREMENT P, NRCan, Esri Japan, METI,

Legend

Facility Location

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Facility Topography

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Boundaries Dataset, 3DEP Elevation Program,

Legend

Facility Location

0 1,000 2,000 4,000

Feet

AECOM 2-6 
A!!

A!

A!

A!

A! A!

A!

A! A!

A!

A!

A!

Baker 

Cover

Groton

Reservoir

Pohegnut

Reservoir

Lake George

Smith

Lake

Long Island

Sound

Birch Plain

Creek Tidal

Marsh

The

Upper

Lagoon

Trails Pond

Beaverdam

Bro ok

Birc h Plai n Creek

H

a

ct

hi ng House

Brook

Briggs Brook

P oquonnock River

Hemps tea d Bro ok

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G rea t Br ook

Ecclest on Brook

Fort Hill Brook

Thames River

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12420 Milestone Center Drive

Germantown, MD 20876

Groundwater Features

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and the GIS User Community

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Water Body

Wetland

River/Stream

Groundwater Flow Direction

Geology

Westerly Granite

Potter Hill Granite Gneiss

Hope Valley Alaskite Gneiss

Rope Ferry Gneiss

New London Gneiss

Mamacoke Formation

Plainfield Formation

Plainfield Formation (quartzite unit)

Wells

A! USGS Monitoring Well

0 2,000 4,000 8,000

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TASMG Groton

A!

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AECOM 2-7 
!?

!?

!?

!?

!?

!?

!?

!?

!?

!?

!?

TMG-03

2.36

AOI1-02

1.99

AOI1-01

1.89

AOI1-03

2.07

TMG-02

1.58

AOI1-04

2.55

TMG-01

3.91

AOI2-01

2.22

AOI2-02

2.16

AOI2-03

2.18

AOI3-01

1.76

2.5

2.0

3.5

3.0

3.5

3.0

2.5

2.0

­ Figure 2-4

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Facility Location

Wetland

Groundwater Elevation Contour

Inferred Groundwater Elevation Contour

Groundwater Flow Direction

Groundwater Elevations, May 2022

12420 Milestone Center Drive

Germantown, MD 20876

0 75 150 300

Feet

Groundwater elevations in ft NAVD88.

AECOM 2-8 
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Cove

Poquonock

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Coastal drainages-Pawcatuck

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PointWatershed

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Reservoir

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Island

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Long Island

Sound

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Surface Water Features

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Water Body

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0 750 1,500 3,000

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3. Summary of Areas of Interest 

The PA evaluated areas where PFAS-containing materials may have been used, stored, 

disposed, or released historically. Based on the PA findings, three potential release areas were

identified at TASMG-Groton and grouped into three AOIs (AECOM, 2020). The potential release 

areas are shown on Figure 3-1.

3.1 AOI 1 Building 320 – Main Hangar

AOI 1 consists of Building 320, the Main Hangar, and the immediate vicinity where potentially 

AFFF-laden water has been released. Releases are suspected to have occurred during the AFFF 

fire suppression system test events between 2008 and the present. System tests involved the 

discharge of water, which may contain residual AFFF, through test ports located on the exterior 

building perimeter.

Potentially AFFF-laden water released from the test ports is collected in barrels that are 

transported and stored adjacent to Building 325, pending disposal off-site. It is also possible that 

water could be spilled during the many test events in the immediate vicinity of the test ports. Test 

ports are located over paved surfaces, but trench drains and catch basins are located near the 

test ports. The trench drains connect to the municipal sanitary sewer system and ultimately 

discharge to the WPCF, but the catch basins channel flow west to an outlet located in a wetland 

area that is associated with a small intermittent stream (Birch Creek) that flows to Baker Cove, 

which ultimately flows to the Long Island Sound. Additionally, surface runoff at the facility generally

drains from east to west, towards the wetland and intermittent stream. Although surface water 

catch basins are not located directly beneath the building test ports, some are very close to the 

test ports, and it is possible that AFFF-laden water could have entered the catch basins during 

testing. Runoff entering stormwater catch basins could have potentially been transported into the 

surface water bodies described. 

Landscaped areas exist adjacent to Building 320. Surface soil in the landscaped areas near 

Building 320 may have received surface water runoff containing AFFF constituents as a result of 

spillage at the test ports during system testing. AFFF releases at AOI 1 may also have infiltrated 

subsurface soil via cracks in pavement, joints between areas that are paved with different 

materials, and the nearby landscaped areas.

3.2 AOI 2 Building 323 – Engine Shop

AOI 2 consists of Building 323, the Engine Shop, and the area between its garage door and the 

perimeter fence, where known AFFF releases have occurred. Releases to the environment 

occurred during the AFFF fire suppression system discharges circa 2010-2012 and 2014. During 

the events, AFFF would have drained to the interior building floor drains that connect to an OWS 

and subsequently discharge to the municipal sanitary sewer system. Additionally, AFFF could 

have escaped the building through the garage door if left open or beneath entryway doors. During 

the PA site visit, the entryway doors appeared to have space between the floor and the bottom of 

the doors even when closed.

AFFF that was contained within the building during the releases drained via floor drains to an 

OWS. Although the OWS was emptied by a contractor following the releases, it is possible that 

AFFF migrated from the OWS to the municipal sanitary sewer system that eventually discharges 

to the WPCF. Surface runoff from the building potentially drained towards a wetland located 

approximately 180 feet northeast (along the northwestern border of the facility) or west towards 

Birch Creek. Birch Creek drains to Baker Cove and eventually the Long Island Sound.
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Landscaped and wooded areas exist adjacent to Building 323. Surface soil in these areas may 

have received AFFF that flowed outwardly from the building or surface water runoff that contained

AFFF as a result of the releases. AFFF releases at AOI 2 may also have infiltrated subsurface 

soil via cracks in pavement, joints between areas that are paved with different materials, and in 

the landscaped and wooded areas.

3.3 AOI 3 Building 325 – State Equipment Storage Building

AOI 3 consists of Building 325 and its adjacent storage area where potentially AFFF-laden water 

generated from the test ports at Building 320 is temporarily stored in barrels prior to disposal by 

a private contractor. Although the disposal of AFFF-laden water is performed in a controlled

manner, it is possible that spillage may occur. Additionally, the storage area is unsheltered, and 

barrels are subject to corrosion due to the elements. The disposal contractor reportedly pumps 

the water from the barrels into a tanker truck; therefore, spillage to the nearby ground surface is 

possible during these activities. 

According to the facility Spill Prevention, Control, and Countermeasure Plan, the barrels are 

stored on spill control pallets, and any liquid spilled is collected in the pallets. If any spills occur 

outside of the pallets, liquid will flow to the surrounding impervious surfaces. Surface runoff may 

flow southeast or northwest, depending on the location of the spill. Grassy surfaces surround the 

storage area to the south, west, and north, and precipitation may facilitate runoff of any spills to 

those areas. Surface runoff to the northwest may have traveled west towards Birch Creek. It is 

not expected that runoff travels to the wetland to the northeast (along the northwestern border of 

the facility).

Surface soil surrounding AOI 3 may have received surface water runoff containing residual AFFF. 

Releases at AOI 3 may have infiltrated subsurface soil through surface soil or via cracks in 

pavement and joints between areas that are paved with different materials.

3.4 Adjacent Sources

Numerous potential off-facility sources adjacent to the facility, not under the control of the 

CTARNG, have been identified. Descriptions of the potential adjacent sources are presented 

below, and the potential adjacent sources are shown on Figure 3-1. 

3.4.1 Groton-New London Airport

The Groton-New London Airport Fire Department responds to emergencies across the airport 

property. According to Groton-New London Fire Department staff, several areas of the airport 

have been used for fire training and nozzle checks by the fire department. One area near the 

north end of Runway 5/23, and one area near the south end of Runway 5/23, have been used for 

Federal Aviation Administration-required annual fire training that involved the discharge of AFFF. 

The events occurred circa 2011 and 2017 and involved the discharge of approximately 100-150 

gallons of 3% AFFF solution. Other annual training events used only water. These releases are 

side-gradient of the TASMG-Groton facility. 

Nozzle check testing that involves the release of AFFF has also occurred at the parking apron 

located west of Runway 15/33 and at the former shooting range colloquially referred to as the 

“Gun Butt”. Nozzle check testing occurs on various runway areas as well but usually involves the 

discharge of only water. The water is sprayed through the same equipment used to spray AFFF; 

therefore, it is possible that this water contains residual AFFF. Both nozzle check testing areas 

are considered downgradient of the TASMG-Groton facility. 
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Fire department staff also stated that the airport terminal is used for the storage of extra AFFF in 

5-gallon buckets and 55-gallon drums. The total volume stored at the terminal fluctuates, but 

approximately 500 gallons were stored at the terminal during PA interviews. The airport terminal 

is considered side-gradient of the TASMG-Groton facility.

3.4.2 Groton-New London Airport Fire Department

The Groton-New London Airport Fire Department is located adjacent to the TASMG-Groton facility 

to the northwest. Aircraft rescue and firefighting (ARFF) training is required under the current 

lease with the CTARNG, according to the airport Master Plan (CAA, 2013).

The fire department occupied another building within the airport property until the previous facility 

was damaged in a structure fire in 2011. The former fire department was located adjacent to the 

private aviation hangars next to Runway 5/23, approximately 1,000 feet east of TASMG-Groton. 

During the 2011 structure fire, the AFFF tank on a 1998 E One Titan 4x4 ARFF truck stored at the 

station was damaged and resulted in the release of 250 gallons of 3% AFFF concentrate. As a 

result, the former fire station location is considered a potential release area. The former fire station 

was repaired and is currently used for the storage of materials, including AFFF in 5-gallon buckets 

and in 55-gallon drums. 

The fire department currently stores two firefighting vehicles, one 2010 Ford Crash Rescue 

Equipment Services Renegade and one 1995 T-1500 Oshkosh ARFF Truck. The former stores 

40 gallons of AFFF 3% concentrate, which produces 1,200 gallons of foam solution, and the latter 

stores 208 gallons of 3% AFFF concentrate, which produces 6,000 gallons of foam solution. The 

two vehicles are typically kept at the current fire department location. The fire department also 

formerly stored the aforementioned 1998 E One Titan 4x4 ARFF truck, which stored 250 gallons 

of AFFF concentrate, and a 1990 Oshkosh T-300 ARFF Truck, which went out of service prior to 

2013 and stored 360 gallons of AFFF concentrate.

Nozzle check testing and fire training are performed by the fire department on airport property, 

but staff also confirmed that nozzle check testing is performed at the current fire station. Runoff 

from the fire station connects to sanitary sewers, which connects to the Groton WPCF. It is 

possible that residual AFFF has been released as a result of nozzle check testing at the current 

fire station. The current fire department location is considered a potential release area sidegradient of the TASMG-Groton facility. 
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Baker

Cove

Poqu onnock

RiverWatershed

Coastal drainag es-Paw catu ck

Point to Eastern

PointWatershed

Coastal drainag es-Paw catu ck

Point to Eastern

PointWatershed

AOI 2

AOI 1

AOI 3

Long

Island

Sound

Birch

Plain Creek

Tidal Marsh

Bu ilding

325 - State Equ ipment

Storag e Bu ilding

Bu ilding 320

- Main Hang ar

Fire Department

AFFF Training Area

 

Groton-New

London Airport

Fire Department

Fire Department

AFFF Training Area

Bu ilding 323 –

Eng ine Shop

Ru nw ay 5/23

Ru nw ay 15/33

Gu n Bu tt/Nozzle

Check Testing Area

Fire Department AFFF 

Nozzle Check Testing Area

Poquonnock River

Fort Hill Brook

Bir c h Plain Creek

B irch Creek

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4. Project Data Quality Objectives

As identified during the Data Quality Objective (DQO) process and outlined in the SI Quality 

Assurance Project Plan (QAPP) Addendum (AECOM, 2021a), the objective of the SI is to identify 

whether there has been a release to the environment at the AOIs identified in the PA. For each 

AOI, ARNG determines if further investigation is warranted, a removal action is required to 

address immediate threats, or whether no further action is warranted. This SI evaluated 

groundwater and soil for presence or absence of relevant compounds at each of the sampled 

AOIs.

4.1 Problem Statement

ARNG will recommend an AOI for Remedial Investigation (RI) if related soil and groundwater 

samples have concentrations of the relevant compounds above the OSD risk-based SLs. The 

SLs are presented in Section 6.1 of this report.

4.2 Information Inputs

Primary information inputs included:

• The PA for TASMG-Groton, Connecticut (AECOM, 2020);

• Analytical data from groundwater and soil samples collected as part of this SI in accordance 

with the site-specific Uniform Federal Policy (UFP)-QAPP Addendum (AECOM, 2021a); and

• Field data collected during the SI, including groundwater elevation and water quality 

parameters measured at the time of sampling.

4.3 Study Boundaries

The scope of the SI was bounded by the property limits of the facility (Figure 2-2). Off-facility sampling 

was not included in the scope of this SI. If future off-facility sampling is required, the proper 

stakeholders will be notified, and necessary rights of entry will be obtained by ARNG with property 

owner(s). Temporal boundaries were limited to the non-winter seasons. Spring was the earliest 

available time field resources were available and weather conditions allowed for completion of the 

study.

4.4 Analytical Approach

Samples were analyzed by Pace Analytical Gulf Coast, accredited under the Department of 

Defense (DoD) Environmental Laboratory Accreditation Program (ELAP; Accreditation Number 

74960) and the National Environmental Laboratory Accreditation Program (NELAP; Certificate

Number 01955). Data were compared to applicable SLs within this document and decision rules 

as defined in the SI QAPP Addendum (AECOM, 2021a).

4.5 Data Usability Assessment

The Data Usability Assessment (DUA), which is provided in Appendix A, is an evaluation at the 

conclusion of data collection activities that uses the results of both data verification and validation 

in the context of the overall project decisions or objectives. Using both quantitative and qualitative 

methods, the assessment determines whether project execution and the resulting data have met 

installation-specific DQOs. Both sampling and analytical activities are considered to assess 
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AECOM 4-2

whether the collected data are of the right type, quality, and quantity to support the decisionmaking (DoD, 2019a; DoD, 2019b; USEPA, 2017).

Based on the DUA, the environmental data collected during the SI were found to be acceptable 

and usable for this SI evaluation with the qualifications documented in the DUA and its associated 

data validation reports. These data are of sufficient quality to meet the objectives and 

requirements of the SI QAPP Addendum (AECOM, 2021a). 
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5. Site Inspection Activities

This section describes the environmental investigation and sampling activities that occurred as 

part of the SI. The SI sampling approach was based on the findings of the PA and implemented 

in accordance with the following approved documents:

• Final Site Inspection Programmatic Uniform Federal Policy-Quality Assurance Project Plan 

(PQAPP) dated March 2018 (AECOM, 2018a);

• Final Programmatic Accident Prevention Plan dated July 2018 (AECOM, 2018b); 

• Final Preliminary Assessment Report, 1109th TASMG-Groton, Groton, Connecticut dated 

June 2020 (AECOM, 2020);

• Final Site Inspection Uniform Federal Policy-Quality Assurance Project Plan Addendum, 

1109th TASMG-Groton, Groton, Connecticut dated September 2021 (AECOM, 2021a); and

• Final Site Safety and Health Plan, 1109th TASMG-Groton, Groton, Connecticut dated May 

2021 (AECOM, 2021b).

The SI field activities were conducted from 12 to 19 May 2022 and consisted of utility clearance,

direct push boring, soil sample collection, temporary monitoring well installation and subsequent 

abandonment, grab groundwater sample collection, and land surveying. Field activities were 

conducted in accordance with the SI QAPP Addendum (AECOM, 2021a).

The following samples were collected during the SI and analyzed for a subset of 18 compounds

by liquid chromatography with tandem mass spectrometry (LC/MS/MS) compliant with Quality 

Systems Manual (QSM) 5.3 Table B-15 to fulfill the project DQOs:

• Thirty-three (33) soil samples from 11 boring locations;

• Eleven (11) grab groundwater samples from 11 temporary well locations; 

• Nineteen (19) quality assurance (QA)/quality control (QC) samples.

Figure 5-1 provides the sample locations for all media across the facility. Table 5-1 presents the 

list of samples collected for each media. Field documentation is provided in Appendix B. A Log 

of Daily Notice of Field Activity was completed throughout the SI field activities, which is provided 

in Appendix B1. Sampling forms are provided in Appendix B2, land survey data are provided in 

Appendix B3, and investigation-derived waste (IDW) polygons are provided in Appendix B4.

Additionally, a photographic log of field activities is provided in Appendix C.

5.1 Pre-Investigation Activities

In preparation for the SI field activities, project team members participated in Technical Project 

Planning (TPP) meetings, performed utility clearance, and sampled decontamination source 

water. Details for each of these activities are presented below.

5.1.1 Technical Project Planning

The US Army Corps of Engineers (USACE) TPP Process, Engineer Manual (EM) 200-1-2 

(USACE, 2016) defines four phases to project planning: 1.) defining the project phase; 2.) 

determining data needs; 3.) developing data collection strategies; and 4.) finalizing the data 

collection plan. The process encourages stakeholder involvement in the SI, beginning with 

defining overall project objectives, including DQOs, and formulating a sampling approach to 

address the AOIs identified in the PA. 
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A combined TPP Meeting 1 and 2 was held on 28 June 2021, prior to SI field activities. The 

combined TPP Meeting 1 and 2 was conducted in general accordance with EM 200-1-2. The 

stakeholders for this SI include the ARNG, CTARNG, USACE, and CTDEEP. Stakeholders were 

provided the opportunity to make comments on the technical sampling approach and methods at 

the combined TPP Meeting 1 and 2. The outcome of the combined TPP Meeting 1 and 2 was 

memorialized in the SI QAPP Addendum (AECOM, 2021a).

A TPP Meeting 3 will be held after the field event to discuss the results of the SI. Meeting minutes 

for TPP 3 will be included in Appendix D of this report. Future TPP meetings will provide an 

opportunity to discuss the results and findings, and future actions, where warranted.

5.1.2 Utility Clearance

AECOM placed a ticket with the “Call Before You Dig” Connecticut utility clearance provider to 

notify them of intrusive work on 25 April 2022. Additionally, AECOM contracted Ground 

Penetrating Radar Systems (GPRS), a private utility location service, to perform utility clearance. 

GPRS performed utility clearance of the proposed boring locations on 12 May 2022 with input 

from the AECOM field team and TASMG-Groton facility staff. General locating services and 

ground-penetrating radar were used to complete the clearance. Additionally, the first 5 feet of each 

boring were pre-cleared using a hand auger to verify utility clearance in shallow subsurface where 

utilities would typically be encountered.

5.1.3 Source Water and Sampling Equipment Acceptability

A potable water source at TASMG-Groton was sampled on 28 October 2021 to assess usability 

for decontamination of drilling equipment. Results of the samples collected from the spigot in 

Building 324 (TMG-PW-01 and TMG-PW-02) confirmed this source to be acceptable for use in 

this investigation; therefore, it was used throughout the field activities. A third sample was 

collected from the drillers tote tank used to contain the potable water from the decontamination 

water sources (TMG-DECON-03). The results of the decontamination water sample collected 

from the drillers tote tank confirmed the tote to be acceptable for use in the investigation as well. 

The samples were analyzed by LC/MS/MS compliant with QSM 5.3 Table B-15. The results of the 

decontamination water sample associated with the wash rack spigot source used during the SI 

are provided in Appendix F. A discussion of the results is presented in the DUA (Appendix A).

Materials that were used within the sampling zone were confirmed as acceptable for use in the 

sampling environment. The checklist of acceptable materials for use in the sampling environment 

was provided in the Standard Operating Procedures (SOPs) appendix to the SI QAPP Addendum 

(AECOM, 2021a). Prior to the start of field work each day, a Sampling Checklist was completed 

as an additional layer of control. The checklist served as a daily reminder to each field team 

member regarding the allowable materials within the sampling environment.

5.2 Soil Borings and Soil Sampling

Borings were installed in grass areas where possible, to avoid disturbing concrete or asphalt 

surfaces; however, soil boring locations AOI02-01 and AOI02-03 were installed in paved areas to 

avoid overhead utilities. Soil samples were collected via direct push technology (DPT), in 

accordance with the SI QAPP Addendum (AECOM, 2021a). A GeoProbe® 7822DT dual-tube 

sampling system was used to collect continuous soil cores to the target depth. A hand auger was 

used to collect soil from the top five feet of the boring, in accordance with AECOM utility clearance 

procedures. The soil boring locations are shown on Figure 5-1, and depths are provided Table 

5-1. Several boring locations were adjusted within a 50-feet offset to allow for utility avoidance.
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Three discrete soil samples were collected from the vadose zone for chemical analysis from each 

soil boring: one surface soil sample (0 to 2 feet bgs), one subsurface soil sample approximately 

2 feet above the groundwater table, and one subsurface soil sample at the mid-point between the 

surface and the groundwater table. 

The soil cores were continuously logged for lithological descriptions by an AECOM field geologist 

using the Unified Soil Classification System (USCS). A photoionization detector (PID) was used 

to screen the breathing zone during boring activities as part of personal safety requirements. 

Observations and measurements were recorded on boring logs (Appendix E) and in a nontreated field logbook (i.e., composition notebook). Depth interval, recovery thickness, PID 

concentrations, moisture, relative density, color (using a Munsell soil color chart), and texture 

(using the USCS) were recorded. The boring logs are provided in Appendix E.

Soil borings completed during the SI were drilled to depths between 10 and 15 feet bgs and

indicate that the dominant lithology of the unconsolidated material underlying the facility is 

comprised of fine- to coarse-grained, well-graded sand. Boring logs showed varying percentages 

of fines (silt) and gravel. Fines in subsurface soil ranged from trace amounts to 45%. Gravel was 

also observed in borings varying from 5% to 45%. The soils observed at the facility have a 

relatively high hydraulic conductivity, with well-graded sands having the highest conductivity. No 

impermeable material layers were observed in SI borings. These site observations are consistent 

with the expected subsurface material conditions.

Each soil sample was collected into laboratory-supplied PFAS-free high-density polyethylene 

(HDPE) bottles and labeled using a PFAS-free marker or pen. Samples were packaged on ice 

and transported via Federal Express (FedEx) under standard chain of custody (CoC) procedures 

to the laboratory and analyzed by LC/MS/MS compliant with QSM 5.3 Table B-15, total organic 

carbon (TOC) (USEPA Method 9060A), and pH (USEPA Method 9045D) in accordance with the

SI QAPP Addendum (AECOM, 2021a).

Field duplicate samples were collected at a rate of 10% and analyzed for the same parameters 

as the accompanying samples. Matrix spike (MS)/MS duplicates (MSDs) were collected at a rate 

of 5% and analyzed for the same parameters as the accompanying samples. In instances when 

non-dedicated sampling equipment was used, such as a hand auger for the shallow soil samples, 

equipment rinsate blanks were collected at a rate of 5% and analyzed for the same parameters 

as the soil samples. A temperature blank was placed in each cooler to ensure that samples were 

preserved at or below 6 degrees Celsius (°C) during shipment.

DPT borings were converted to temporary wells, which were subsequently abandoned in 

accordance with the SI QAPP Addendum (AECOM, 2021a).

5.3 Temporary Well Installation and Groundwater Grab Sampling

Temporary wells were installed using a GeoProbe® 7822DT dual-tube sampling system. Once 

the borehole was advanced to the desired depth, a temporary well was constructed of a 5-foot

section of 2-inch Schedule 40 poly-vinyl chloride (PVC) screen with sufficient casing to reach 

ground surface. New PVC pipe and screen were used to avoid cross contamination between 

locations. The screen intervals for the temporary wells are provided in Table 5-2.

Groundwater samples were collected after a period of time following well installation to allow 

groundwater to infiltrate and recharge the temporary well screen intervals. After the recharge 

period, groundwater samples were collected using a peristaltic pump with PFAS-free HDPE 

tubing. The temporary wells were purged at a rate determined in the field to reduce turbidity and 

draw down prior to sampling. Water quality parameters (e.g., temperature, specific conductance, 

pH, dissolved oxygen, and oxidation-reduction potential) were measured using a water quality 

meter and recorded on the field sampling form (Appendix B2) before each grab sample was 
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AECOM 5-4

collected. Additionally, a subsample of each groundwater sample was collected in a separate 

container, and a shaker test was completed to identify if there were any foaming. No foaming was 

noted in any of the groundwater samples.

Each sample was collected into laboratory-supplied PFAS-free HDPE bottles and labeled using 

a PFAS-free marker or pen. Samples were packaged on ice and transported via FedEx under 

standard CoC procedures to the laboratory and analyzed by LC/MS/MS compliant with QSM 5.3

Table B-15 in accordance with the SI QAPP Addendum (AECOM, 2021a).

Field duplicate samples were collected at a rate of 10% and analyzed for the same parameters 

as the accompanying samples. MS/MSDs were collected at a rate of 5% and analyzed for the 

same parameters as the accompanying samples. One field reagent blank was collected in 

accordance with the PQAPP (AECOM, 2018a). A temperature blank was placed in each cooler to 

ensure that samples were preserved at or below 6°C during shipment.

Following well surveying (described below in Section 5.5), temporary wells were abandoned in 

accordance with the SI QAPP Addendum (AECOM, 2021a) by removing the PVC and backfilling 

the hole with bentonite chips. Upon completion of well abandonment, the ground surface at each 

location was patched to match existing surrounding conditions.

5.4 Synoptic Water Level Measurements

A synoptic groundwater gauging event was performed on 19 May 2022. Groundwater elevation 

measurements were collected from the 11 new temporary monitoring wells. Water level 

measurements were taken from the northern side of the well casing. A groundwater flow contour 

map is provided in Figure 2-4. Groundwater elevation data are provided in Table 5-2.

5.5 Surveying

The northern side of each well casing was surveyed by Connecticut-licensed land surveyors 

following guidelines provided in the SOPs provided in the SI QAPP Addendum (AECOM, 2021a). 

Survey data from the newly installed wells on the facility were collected on 19 May 2022 in the 

applicable Universal Transverse Mercator zone projection with World Geodetic System 1984

(WGS84) datum (horizontal) and North American Vertical Datum 1988 (vertical). The surveyed 

well data are provided in Appendix B3.

5.6 Investigation-Derived Waste

As of the date of this report, the disposal of IDW is not regulated federally. IDW generated during 

the SI is considered non-hazardous waste and was managed in accordance with the SI QAPP 

Addendum (AECOM, 2019a) and with the DAGuidance for Addressing Releases of PFAS, Q18 (DA, 

2018).

Soil IDW (i.e., soil cuttings) generated during the SI activities were left in place at the point of the 

source. The soil cuttings were distributed on the ground surface on the downgradient side of the 

boring. The soil IDW was not sampled and assumes the characteristics of the associated soil 

samples collected from that source location.

Liquid IDW generated during SI activities (i.e., purge water, development water, and 

decontamination fluids) were discharged directly to the ground at the source. The liquid IDW was 

not sampled and assumes the characteristics of the associated groundwater samples collected 

from that source location.
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 5-5

Geographic coordinates were collected using a global positioning system (GPS) around each 

location where IDW was placed (i.e., an IDW polygon). The IDW polygons are displayed on the 

figure in Appendix B4.

Other solids such as spent personal protective equipment, plastic sheeting, tubing, rope, unused 

monitoring well construction materials, and other environmental media generated during the field 

activities were disposed of at a licensed solid waste landfill.

5.7 Laboratory Analytical Methods

Samples were analyzed by LC/MS/MS compliant with QSM 5.3 Table B-15 at Pace Analytical Gulf 

Coast in Baton Rouge, Louisiana, a DoD ELAP and NELAP certified laboratory. Soil samples 

were also analyzed for TOC using USEPA Method 9060A and pH by USEPA Method 9045D.

5.8 Deviations from SI QAPP Addendum

No deviations from the SI QAPP Addendum were identified during SI field work or review of the 

field documentation.
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 5-6

THIS PAGE INTENTIONALLY BLANK
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, TASMG-Groton, Connecticut

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

LC/MS/MS compliant with QSM 5.3 Table B-15TOC(USEPA Method 9060A)

pH (USEPA Method 9045D)

Comments

AOI01-01-SB-00-02 5/16/2022 10:45 0 - 2 x x x

AOI01-01-SB-03-04 5/16/2022 12:00 3 - 4 x

AOI01-01-SB-04-06 5/16/2022 12:15 4 - 6 x

AOI01-02-SB-00-02 5/16/2022 14:00 0 - 2 x

AOI01-02-SB-04-05 5/16/2022 14:45 4 - 5 x

AOI01-02-SB-08-09 5/16/2022 14:55 8 - 9 x

AOI01-03-SB-00-02 5/17/2022 8:15 0 - 2 x

AOI01-03-SB-00-02-D 5/17/2022 8:15 0 - 2 x FD

AOI01-03-SB-03-05 5/17/2022 8:20 3 - 5 x

AOI01-03-SB-05-07 5/17/2022 8:50 5 - 7 x

AOI01-04-SB-00-02 5/19/2022 9:15 0 - 2 x

AOI01-04-SB-00-02-MS 5/19/2022 9:15 0 - 2 x MS

AOI01-04-SB-00-02-MSD 5/19/2022 9:15 0 - 2 x MSD

AOI01-04-SB-03-05 5/19/2022 9:20 3 - 5 x

AOI01-04-SB-03-05-D 5/19/2022 9:20 3 - 5 x FD

AOI01-04-SB-07-08 5/19/2022 9:30 7 - 8 x

AOI02-01-SB-00-02 5/18/2022 11:30 0 - 2 x

AOI02-01-SB-04-05 5/18/2022 11:40 4 - 5 x

AOI02-01-SB-05-06.5 5/18/2022 12:30 5 - 6.5 x

AOI02-01-SB-05-06.5-D 5/18/2022 12:30 5 - 6.5 x FD

AOI02-02-SB-00-02 5/17/2022 14:30 0 - 2 x x x

AOI02-02-SB-00-02-D 5/17/2022 14:30 0 - 2 x x FD

AOI02-02-SB-03-05 5/18/2022 8:05 3 - 5 x

AOI02-02-SB-05-07 5/18/2022 8:10 5 - 7 x

AOI02-03-SB-00-02 5/18/2022 9:40 0 - 2 x

AOI02-03-SB-04-06 5/18/2022 10:40 4 - 6 x

AOI02-03-SB-06-07 5/18/2022 10:45 6 - 7 x

AOI03-01-SB-00-02 5/17/2022 11:50 0 - 2 x x x

AOI03-01-SB-00-02-MS 5/17/2022 11:50 0 - 2 x x MS

AOI03-01-SB-00-02-MSD 5/17/2022 11:50 0 - 2 x x MSD

AOI03-01-SB-03-05 5/17/2022 12:00 3 - 5 x

AOI03-01-SB-05-07 5/17/2022 12:50 5 - 7 x x x

TMG-01-SB-00-02 5/18/2022 14:15 0 - 2 x x x

TMG-01-SB-02-04 5/18/2022 14:20 2 - 4 x

TMG-01-SB-04-05 5/18/2022 14:25 4 - 5 x

TMG-02-SB-00-02 5/17/2022 10:15 0 - 2 x

TMG-02-SB-00-02-MS 5/17/2022 10:15 0 - 2 x MS

TMG-02-SB-00-02-MSD 5/17/2022 10:15 0 - 2 x MSD

TMG-02-SB-02-04 5/17/2022 10:20 2 - 4 x

TMG-02-SB-05-07 5/17/2022 10:30 5 - 7 x

TMG-03-SB-00-02 5/16/2022 9:10 0 - 2 x

TMG-03-SB-00-02-D 5/16/2022 9:15 0 - 2 x FD

TMG-03-SB-03-04 5/16/2022 9:45 3 - 4 x

TMG-03-SB-06-07 5/16/2022 9:50 6 - 7 x

Soil Samples

AECOM 5-7 
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, TASMG-Groton, Connecticut

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

LC/MS/MS compliant with QSM 5.3 Table B-15TOC(USEPA Method 9060A)

pH (USEPA Method 9045D)

Comments

AOI01-01-GW 5/17/2022 10:50 NA x

AOI01-01-GW-D 5/17/2022 10:55 NA x FD

AOI01-02-GW 5/17/2022 11:55 NA x

AOI01-03-GW 5/17/2022 13:50 NA x

AOI01-03-GW-MS 5/17/2022 13:50 NA x MS

AOI01-03-GW-MSD 5/17/2022 13:50 NA x MSD

AOI01-04-GW 5/19/2022 12:30 NA x

AOI02-01-GW 5/19/2022 9:40 NA x

AOI02-02-GW 5/18/2022 11:00 NA x

AOI02-02-GW-D 5/18/2022 11:05 NA x FD

AOI02-03-GW 5/18/2022 12:25 NA x

AOI03-01-GW 5/18/2022 8:50 NA x

TMG-01-GW 5/19/2022 11:30 NA x

TMG-02-GW 5/17/2022 15:45 NA x

TMG-03-GW 5/17/2022 9:25 NA x

TMG-ERB-01 5/17/2022 15:30 NA x DPT shoe

TMG-ERB-02 5/18/2022 13:30 NA x Hand auger

TMG-ERB-03 5/19/2022 10:30 NA x Hand auger

TMG-FRB-01 5/19/2022 11:00 NA x NA

TMG-PW-01 10/28/2021 8:35 NA x Spigot

TMG-PW-02 10/28/2021 8:30 NA x Spigot

TMG-DECON-03 5/19/2022 11:30 NA x Water tank

Notes:

ASTM = American Society for Testing and Materials

bgs = below ground surface

ERB = equipment rinsate blank

FD = field duplicate

FRB = field reagent blank

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MS/MSD = matrix spike/ matrix spike duplicate

PFAS = per- and polyfluoroalkyl substances

QSM = Quality Systems Manual

TOC = total organic carbon

USEPA = United States Environmental Protection Agency

Quality Control Samples

Groundwater Samples

AECOM 5-8 
Table 5-2

Soil Boring Depths, Temporary Well Screen Intervals, and Groundwater Elevations

Site Inspection Report, TASMG-Groton, Connecticut

Area of 

Interest

Boring 

Location

Soil Boring 

Depth 

(feet bgs)

Temporary Well 

Screen Interval 

(feet bgs)

Top of Casing 

Elevation 

(feet NAVD88)

Ground Surface 

Elevation 

(feet NAVD88)

Depth to 

Water

(feet btoc)

Dept

Wa

(feet 

AOI01-01 15 7 - 121 13.9 11.02 12.01 9.

AOI01-02 15 9 - 141 12.08 10.44 10.09 8.4

AOI01-03 15 7 - 121 13.37 10.50 11.3 8.4AOI01-04 15 8 - 131 13.73 12.07 11.18 9.5

TMG-03 15 7 - 121 11.13 9.71 8.77 7.3

AOI02-01 15 7 - 121 11.83 10.41 9.61 8.

AOI02-02 15 7 - 121 12.01 10.20 9.85 8.0AOI02-03 15 7 - 121 11.11 10.28 8.93 8.

TMG-01 10 5 - 10 5.8 5.03 1.89 1.

TMG-02 15 7 - 121 10.81 9.17 9.23 7.5

3 AOI03-01 15 8 - 131 12.9 10.53 11.14 8.7

Notes:

1 Temporary well screen set above total depth to capture groundwater interface

bgs = below ground surfacebtoc = below top of casingNA = not applicableNAVD88 = North American Vertical Datum 1988

12

AECOM 
Site Inspection Report

1109th TASMG-Groton, Connecticut

THIS PAGE INTENTIONALLY BLANK

AECOM 5-10
!?

!?

!?

!?

!?

!?

!?

!?

!?

!?

!?

B irch

Creek

AOI 2

AOI 1

AOI 3

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 5-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/6/2022

12/6/2022

12/6/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/6/2022

1:1,800

Legend

!? Soil Boring/Groundwater Location

Area of Interest

Facility Location

Wetland

River/Stream

Surface Water Flow Direction

Groundwater Flow Direction

Site Inspection Sample Locations

12420 Milestone Center Drive

Germantown, MD 20876

0 75 150 300

Feet

AECOM 5-11
Site Inspection Report

1109th TASMG-Groton, Connecticut

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AECOM 5-12
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 6-1

6. Site Inspection Results

This section presents the analytical results of the SI. The SLs used in this evaluation are 

presented in Section 6.1. A discussion of the results for each AOI is provided in Section 6.3

through Section 6.5. Table 6-2 through Table 6-4 present results in soil or groundwater for the 

relevant compounds. Tables that contain all results are provided in Appendix F, and the 

laboratory reports are provided in Appendix G. 

6.1 Screening Levels 

The DoD has adopted a policy to retain facilities in the CERCLA process based on risk-based 

SLs for soil and groundwater, as described in a memorandum from the OSD dated 6 July 2022 

(Assistant Secretary of Defense, 2022). The ARNG program under which this SI was performed 

follows this DoD policy. Should the maximum site concentration for sampled media exceed the 

SLs established in the OSD memorandum, the AOI will proceed to the next phase under CERCLA. 

The SLs established in the OSD memorandum apply to the five compounds presented on Table 

6-1 below.

Table 6-1: Screening Levels (Soil and Groundwater)

Analyteb

Residential

(Soil)

(μg/kg)a 

0-2 feet bgs

Industrial/ 

Commercial 

Composite 

Worker 

(Soil)

(μg/kg)a 

2-15 feet bgs

Tap Water

(Groundwater) 

(ng/L)a

PFOA 19 250 6 

PFOS 13 160 4

PFBS 1,900 25,000 601 

PFHxS 130 1,600 39

PFNA 19 250 6 

Notes:

bgs = below ground surface; μg/kg = micrograms per kilogram; ng/L = nanograms per liter

a.) Assistant Secretary of Defense, 2022. Risk Based Screening Levels in Groundwater and Soil using United States Environmental Protection 

Agency’s (USEPA’s) Regional Screening Level Calculator. Hazard Quotient (HQ) = 0.1. 6 July 2022. 

b.) Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to as GenX) was not included 

as an analyte at the time of this SI. Based on the CSM developed during the PA and revised based on SI findings, the presence of HFPODA is not anticipated at the facility because HFPO-DA is generally not a component of MIL-SPEC AFFF and based on its history including 

distribution limitations that restricted use of GenX, it is generally not a component of other products the military used. In addition, it is 

unlikely that GenX would be an individual chemical of concern in the absence of other PFAS. 

The data in the subsequent sections are compared against the SLs presented in Table 6-1. The 

SLs for groundwater are based on direct ingestion. The SLs for soil are based on incidental 

ingestion and are applied to the depth intervals reasonably anticipated to be encountered by the 

receptors identified at the facility: the residential scenario is applied to surface soil results (0 to 2 

feet bgs), and the industrial/commercial worker scenario is applied to shallow subsurface soil 

results (2 to 15 feet bgs). The SLs are not applied to deep subsurface soil results (>15 feet bgs) 

because 15 feet is the anticipated limit of construction activities. 
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 6-2

6.2 Soil Physicochemical Analyses

To provide basic soil parameter information, soil samples were analyzed for TOC and pH, which 

are important for evaluating transport through the soil medium. Appendix F contains the results 

of the TOC and pH sampling. 

The data collected in this investigation will be used in subsequent investigations, where 

appropriate, to assess fate and transport. According to the Interstate Technology Regulatory 

Council (ITRC), several important partitioning mechanisms include hydrophobic and lipophobic 

effects, electrostatic interactions, and interfacial behaviors. At relevant environmental pH values, 

certain PFAS are present as organic anions and are therefore relatively mobile in groundwater 

(Xiao et al., 2015), but tend to associate with the organic carbon fraction that may be present in 

soil or sediment (Higgins and Luthy, 2006; Guelfo and Higgins, 2013). When sufficient organic 

carbon is present, organic carbon normalized distribution coefficients (Koc values) can help in 

evaluating transport potential, though other geochemical factors (for example, pH and presence 

of polyvalent cations) may also affect PFAS sorption to solid phases (ITRC, 2018).

6.3 AOI 1

This section presents the analytical results for soil and groundwater in comparison to SLs for 

AOI 1: Building 320 (Main Hangar). The soil and groundwater results are summarized on Table 

6-2 through Table 6-4. Soil and groundwater results are presented on Figure 6-1 through Figure 

6-7.

6.3.1 AOI 1 Soil Analytical Results

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 through Table 

6-3 summarize the soil results.

Soil was sampled from surface soil (0 to 2 feet bgs) and shallow subsurface soil (3 to 9 feet bgs) 

from boring locations AOI01-01 through AOI01-04. PFOA, PFOS, PFBS, PFHxS, and PFNA were 

detected in soil at concentrations below their respective SLs. All detected concentrations in 

surface soil were equal to or less than 0.596 J (estimated concentration) micrograms per kilogram 

(μg/kg).

PFOA, PFOS, PFBS, PFHxS, and PFNA were also detected in shallow subsurface soil at AOI 1. 

All constituents were detected at concentrations equal to or less than 0.180 J μg/kg. No analytes 

exceeded SLs in subsurface soil.

Soil was also sampled from surface soil (0 to 2 feet bgs) and shallow subsurface soil (3 to 7 feet 

bgs) at side-gradient location TMG-03. PFOA, PFOS, PFBS, PFHxS, and PFNA were detected 

in surface soil below the SLs, and PFOA, PFOS, and PFNA were detected below the SLs in 

shallow subsurface soil. PFBS and PFHxS were not detected in shallow subsurface soil at TMG03.

6.3.2 AOI 1 Groundwater Analytical Results

Figure 6-6 and Figure 6-7 present the ranges of detections in groundwater. Table 6-4 

summarizes the groundwater results.

Groundwater was sampled from temporary monitoring wells AOI01-01 through AOI01-04. The 

following exceedances of the SLs were measured:

• PFOA was detected above the SL of 6 nanograms per liter (ng/L) in one of the four 

wells, with a concentration of 8.20 ng/L at AOI01-04. 
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 6-3

• PFOS was detected above the SL of 4 ng/L at three of the four wells, with concentrations

ranging from of 6.96 ng/L to 53.8 ng/L.

• PFNA was detected above the SL of 6 ng/L at one of the four wells, with a concentration

of 6.89 ng/L at AOI01-04.

PFBS and PFHxS were detected below their SLs in all four wells, with their highest concentrations 

occurring at AOI01-04. 

Groundwater was also sampled from side-gradient location TMG-03. PFOS exceeded the SL, 

with a concentration of 9.91 ng/L. PFOA, PFBS, PFHxS, and PFNA were detected below their 

SLs at TMG-03. 

6.3.3 AOI 1 Conclusions

Based on the results of the SI, PFOA, PFOS, PFBS, PFHxS, and PFNA were detected in soil, 

below their SLs. PFOA, PFOS, and PFNA were detected in groundwater, at concentrations above 

their SLs. Based on the exceedances of the SLs in groundwater, further evaluation at AOI 1 is 

warranted. 

6.4 AOI 2 

This section presents the analytical results for soil and groundwater in comparison to SLs for

AOI 2: Building 323 (Engine Shop). The results in soil and groundwater are summarized on Table 

6-2 through Table 6-4. Soil and groundwater results are presented on Figure 6-1 through Figure

6-7.

6.4.1 AOI 2 Soil Analytical Results

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 through Table 

6-3 summarize the soil results.

Soil was sampled from surface soil (0 to 2 feet bgs) and shallow subsurface soil (3 to 7 feet bgs)

from boring locations AOI02-01 through AOI02-03. PFOA, PFOS, PFBS, and PFNA were 

detected in surface soil, at concentrations equal to or less than 1.25 μg/kg and below their SLs; 

PFHxS was not detected. PFOA, PFOS, PFBS, PFHxS, and PFNA were detected in shallow 

subsurface soil, at concentrations equal to or less than 0.835 J μg/kg. All detected concentrations 

in shallow subsurface soil were below the respective SLs. 

Soil was also sampled from surface soil (0 to 2 feet bgs) and shallow subsurface soil (2 to 7 feet 

bgs) at the potentially upgradient location TMG-01 and downgradient location TMG-02. PFOS 

and PFNA were detected in surface soil, below their SLs, at each location. PFOA, PFBS, and 

PFHxS were not detected in surface soil at TMG-01 or TMG-02. PFOA, PFOS, PFHxS, and PFNA 

were detected below their SLs in shallow subsurface soil at TMG-01, and PFOA, PFOS, and 

PFNA were detected below their SLs in shallow subsurface soil at TMG-02. PFHxS was not 

detected in shallow subsurface soil at TMG-02, and PFBS was not detected in shallow subsurface 

soil at either location. 

6.4.2 AOI 2 Groundwater Analytical Results

Figure 6-6 and Figure 6-7 present the ranges of detections in groundwater. Table 6-4 

summarizes the groundwater results. 

Groundwater was sampled from temporary monitoring wells AOI02-01 through AOI02-03. The 

following exceedances of the SLs were measured: 
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 6-4

• PFOA was detected above the SL of 6 ng/L in all three wells, with concentrations

ranging from 6.82 ng/L to 143 ng/L.

• PFOS was detected above the SL of 4 ng/L at two of the three wells, with concentrations

ranging from of 4.63 ng/L at AOI02-02 to 11.8 ng/L at AOI02-03.

• PFNA was detected above the SL of 6 ng/L at two of the three wells, with concentrations

ranging from of 8.57 ng/L at AOI02-03 to 18.5 ng/L at AOI02-02.

PFBS and PFHxS were detected below their SLs in all three wells.

Groundwater was also sampled from the potentially upgradient location TMG-01 and 

downgradient location TMG-02. PFOA, PFOS, PFBS, PFHxS, and PFNA were detected below 

their SLs at TMG-01. PFOA and PFOS were detected above their SLs at TMG-02, with 

concentrations of 10.8 ng/L and 15.0 ng/L, respectively. PFBS, PFHxS, and PFNA were detected 

below their SLs at TMG-02. 

6.4.3 AOI 2 Conclusions

Based on the results of the SI, PFOA, PFOS, PFBS, PFHxS, and PFNA were detected in soil 

below their respective SLs. PFOA, PFOS, and PFNA were detected in groundwater, at 

concentrations above their SLs. Based on the exceedances of the SLs in groundwater, further 

evaluation at AOI 2 is warranted.

6.5 AOI 3 

This section presents the analytical results for soil and groundwater in comparison to SLs for 

AOI 3: Building 325 (State Equipment Storage Building). The results in soil and groundwater are 

presented in Table 6-2 through Table 6-4. Soil and groundwater results are presented on Figure 

6-1 through Figure 6-7.

6.5.1 AOI 3 Soil Analytical Results

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 through Table 

6-3 summarize the soil results.

Soil was sampled from surface soil (0 to 2 feet bgs) and shallow subsurface soil (3 to 7 feet bgs) 

from boring location AOI03-01. PFOS and PFNA were detected below their SLs in surface and 

shallow subsurface soil, and no other relevant compounds were detected in soil at AOI03-01. 

6.5.2 AOI 3 Groundwater Analytical Results

Figure 6-6 and Figure 6-7 present the ranges of detections in groundwater. Table 6-4 

summarizes the groundwater results. 

Groundwater was sampled from temporary monitoring well AOI03-01. PFOS was detected above 

the SL of 4 ng/L, with a concentration of 9.89 ng/L. PFOA, PFBS, PFHxS, and PFNA were 

detected in groundwater, below their SLs, at concentrations equal to or less than 3.74 J ng/L. 

6.5.3 AOI 3 Conclusions

Based on the results of the SI, PFOS and PFNA were detected in soil below their respective SLs. 

PFOS was detected in groundwater, at a concentration above its SL. Based on the exceedance 

of the PFOS SLs in groundwater, further evaluation at AOI 3 is warranted.
Table 6-2

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Surface Soil

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result 

PFBS 1900 ND U ND U ND U ND U 0.032 J 0.030 J 0.030 J 0.024 J 0.044 J 0.020 JPFHxS 130 0.051 J ND U ND UJ 0.033 J 0.048 J 0.038 J 0.045 J ND U ND U ND UPFNA 19 0.041 J 0.047 J 0.064 J 0.076 J 0.229 J 0.102 J 0.089 J 0.022 J 1.17 ND U

PFOA 19 0.168 J 0.209 J ND UJ 0.096 J 0.140 J 0.224 J 0.218 J ND U 1.25 ND U

PFOS 13 0.186 J 0.234 J 0.182 J 0.228 J 0.596 J 0.453 J 0.411 J 0.100 J 0.462 J 0.077 J

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and AbbreviationsAASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicateJ = Estimated concentration DL detection limitU = The analyte was not detected at a level greater than or equal to the adjusted DL ft feet

HQ hazard quotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierSB soil boringTASMG Theater Aviation Support Maintenance GroupTMG TASMG-GrotonUSEPA United States Environmental Protection Agencyμg/kg micrograms per kilogram

Soil, LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on residential scenario for incidental ingestion of contaminated soil.

AOI02-03-SB

05/18/20

0-2 ft

AOI02-01-SB-00-02

05/18/2022

0-2 ft

AOI02-02-SB-00-02

05/18/2022

0-2 ft

AOI02

AOI01-03-SB-00-02-D

05/17/2022

0-2 ft

AOI01-04-SB-00-02

05/19/2022

0-2 ft

AOI01

TMG-03-SB-00-02 TMG-03-SB-00-02-D

05/16/2022 05/16/2022

0-2 ft 0-2 ft

AOI01-02-SB-00-02

05/16/2022

0-2 ft

AOI01-03-SB-00-02

05/17/2022

0-2 ft

Area of Interest

Sample ID

Sample Date

Depth

AOI01-01-SB-00-02

05/16/2022

0-2 ft

AECOM 6-5

AECOM 
Table 6-2

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Surface Soil

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual

PFBS 1900 ND U ND U ND UPFHxS 130 ND U ND U ND UPFNA 19 0.121 J 0.031 J 0.027 JPFOA 19 ND U ND U ND UPFOS 13 0.422 J 0.086 J 0.245 J

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and AbbreviationsAASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicate

J = Estimated concentration DL detection limitU = The analyte was not detected at a level greater than or equal to the adjusted DL ft feet

HQ hazard quotientID identificationLCMSMS liquid chromatography with tandem mLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierSB soil boringTASMG Theater Aviation Support MaintenancTMG TASMG-GrotonUSEPA United States Environmental Protectiμg/kg micrograms per kilogram

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on residential scenario for incidental ingestion of contaminated soil.

Soil, LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

AOI02

TMG-01-SB-00-02 TMG-02-SB-00-02

05/17/2022

0-2 ft

05/18/2022

0-2 ft

AOI03

AOI03-01-SB-00-02

05/17/2022

0-2 ft

Area of Interest

Sample ID

Sample Date

Depth

AECOM 
Table 6-3

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Resu

PFBS 25000 ND U ND U 0.046 J ND U ND U ND U ND U ND U ND PFHxS 1600 ND U ND U ND U ND U ND U ND U 0.030 J ND UJ ND PFNA 250 0.025 J ND U 0.026 J ND U 0.035 J ND U 0.073 J 0.074 J ND PFOA 250 0.091 J ND U ND U ND U ND U ND U 0.138 J 0.128 J ND PFOS 160 0.103 J ND U 0.137 J ND U 0.086 J ND U 0.180 J 0.176 J ND 

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and AbbreviationsAASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicate

J = Estimated concentration DL detection limitU = The analyte was not detected at a level greater than or equal to the adjusted DL ft feet

UJ = The analyte was not detected at a level greater than or equal to the adjusted DL. However, the reported adjusted DL is approximate and may be inaccurate or imprecise. HQ hazard quotient

ID identificationLCMSMS liquid chromatography with tandem mLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierSB soil boringTASMG Theater Aviation Support MaintenancTMG TASMG-GrptonUSEPA United States Environmental Protectiμg/kg micrograms per kilogram

Area of Interest

Sample ID

Sample Date

Depth

AOI01-01-SB-03-04

05/16/2022

3-4 ft

AOI01

AOI01-01-SB-04-06

05/16/2022

4-6 ft

AOI01-02-SB-04-05

05/16/2022

4-5 ft

AOI01-04-SB-03-05

05/16/2022 05/19/2022

8-9 ft

AOI01-03-SB-03-05

05/17/2022

3-5 ft

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of contaminated soil.

Soil, LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

AOI01-04-SB-03-05-D

05/19/2022

3-5 ft

AOI01

0

AOI01-03-SB-05-07

05/17/2022

5-7 ft 3-5 ft

AOI01-02-SB-08-09

AECOM 
Table 6-3

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Resu

PFBS 25000 ND U ND U ND U ND U 0.032 J 0.036 J ND U ND U ND PFHxS 1600 ND U 0.373 J 0.117 J 0.152 J ND U ND U ND U ND U 0.058 PFNA 250 ND U 0.029 J ND U ND U 0.488 J 0.430 J 0.089 J 0.069 J 0.208 PFOA 250 ND U 0.666 J ND U ND U 0.835 J 0.422 J ND U 0.141 J 0.180 PFOS 160 ND U 0.097 J ND U ND U 0.370 J 0.329 J 0.206 J 0.068 J 0.783 

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and AbbreviationsAASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicate

J = Estimated concentration DL detection limitU = The analyte was not detected at a level greater than or equal to the adjusted DL ft feet

UJ = The analyte was not detected at a level greater than or equal to the adjusted DL. However, the reported adjusted DL is approximate and may be inaccurate or imprecise. HQ hazard quotient

ID identificationLCMSMS liquid chromatography with tandem mLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierSB soil boringTASMG Theater Aviation Support MaintenancTMG TASMG-GrptonUSEPA United States Environmental Protectμg/kg micrograms per kilogram

Soil, LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of contaminated soil.

Area of Interest AOI02

Sample ID

Sample Date

Depth

AOI02-01-SB-05-06.5

05/18/2022

5-6.5 ft

AOI02-01-SB-04-05

05/18/2022

4-5 ft

TMG-03-SB-06-07

05/16/2022

6-7 ft

AOI01

AOI02-01-SB-05-06.5-D

05/18/2022

5-6.5 ft

AOI02-02-SB-03-05

05/18/2022

3-5 ft 6-7 ft

AOI02-02-SB-05-07

05/18/2022

5-7 ft

AOI02-03-SB-04-06

05/18/2022

4-6 ft

TMG

0

AOI02-03-SB-06-07

05/18/2022

AECOM 
Table 6-3

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Shallow Subsurface Soil

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual

PFBS 25000 ND U ND U ND U ND UPFHxS 1600 ND U ND U ND U ND UPFNA 250 0.025 J ND U 0.052 J 0.158 JPFOA 250 0.121 J ND U ND U ND UPFOS 160 0.059 J ND U 0.579 J 0.472 J

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and AbbreviationsAASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicate

J = Estimated concentration DL detection limitU = The analyte was not detected at a level greater than or equal to the adjusted DL ft feet

UJ = The analyte was not detected at a level greater than or equal to the adjusted DL. However, the reported adjusted DL is approximate and may be inaccurate or imprecise. HQ hazard quotient

ID identificationLCMSMS liquid chromatography with tandem mLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierSB soil boringTASMG Theater Aviation Support MaintenancTMG TASMG-GrptonUSEPA United States Environmental Protectiμg/kg micrograms per kilogram

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of contaminated soil.

AOI03-01-SB-05-07

05/17/2022

5-7 ft

Soil, LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)

TMG-02-SB-05-07

05/17/2022

5-7 ft

AOI03-01-SB-03-05

05/17/2022

Depth 2-4 ft 3-5 ft

Area of Interest AOI02 AOI03

Sample ID

Sample Date

TMG-02-SB-02-04

05/17/2022

AECOM 
Table 6-4

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Result Qual Resu

PFBS 601 0.813 J 0.974 J 1.52 J 7.68 8.29 7.76 20.2 J 28.6 J 90.2

PFHxS 39 1.55 J 1.78 J 3.42 J 19.5 31.0 9.48 6.48 9.83 3.23 

PFNA 6 3.07 J 3.61 J 2.37 J 1.15 J 6.89 3.76 J 13.9 18.5 8.57PFOA 6 1.46 J 1.63 J 3.83 J 4.88 8.20 143 58.3 J 82.9 J 6.82PFOS 4 1.99 J 2.44 J 6.96 21.5 53.8 1.60 J 4.63 6.57 11.8

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and Abbreviations

AASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicate

J = Estimated concentration DL detection limit

GW groundwaterHQ hazard quotientID identificationLCMSMS liquid chromatography with tandem mLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierTASMG Theater Aviation Support MaintenancTMG TASMG-GrotonUSEPA United States Environmental Protecting/l nanogram per liter

Water, LCMSMS compliant with QSM 5.3 Table B-15 (ng/l)

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022 Groundwater screening levels based on residential scenario for direct ingestion of groundwater.

AOI01 AOI02

AOI02-02-GW-D

05/18/2022

AO

0

AOI02-01-GW

05/19/2022

AOI02-02-GW

05/18/2022

AOI01-03-GW

05/17/2022

AOI01-04-GW

05/19/2022

AOI01-01-GW-D

05/17/2022

AOI01-02-GW

05/17/2022

Area of Interest

Sample ID

Sample Date

AOI01-01-GW

05/17/2022

AECOM 
Table 6-4

PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater

Site Inspection Report, TASMG-Groton

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual

PFBS 601 1.37 J 4.10 8.65 0.895 J

PFHxS 39 2.63 J 7.27 16.1 3.89 JPFNA 6 3.70 J 1.64 J 5.45 3.56 JPFOA 6 3.74 J 3.48 J 10.8 1.22 JPFOS 4 9.89 3.29 J 15.0 9.91

Notes: Chemical AbbreviationsND = Analyte not detected above the LOD PFBS perfluorobutanesulfonic acidLOD values are presented in Appendix F PFHxS perfluorohexanesulfonic acidGrey Fill Detected concentration exceeded OSD Screening Levels PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

References PFOS perfluorooctanesulfonic acid

Acronyms and Abbreviations

AASF Army Aviation Support FacilityAOI Area of Interest

Interpreted Qualifiers D duplicate

J = Estimated concentration DL detection limit

GW groundwaterHQ hazard quotientID identificationLCMSMS liquid chromatography with tandem mLOD limit of detectionND analyte not detected above the LODOSD Office of the Secretary of DefenseQSM Quality Systems ManualQual interpreted qualifierTASMG Theater Aviation Support MaintenancTMG TASMG-GrotonUSEPA United States Environmental Protecting/l nanogram per liter

TMG-03-GW

05/17/2022

Water, LCMSMS compliant with QSM 5.3 Table B-15 (ng/l)

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022 Groundwater screening levels based on residential scenario for direct ingestion of groundwater.

Sitewide

TMG-01-GW

05/19/2022

TMG-02-GW

05/17/2022

Area of Interest

Sample ID

Sample Date

AOI03

AOI03-01-GW

05/18/2022

AECOM 
Site Inspection Report

1109th TASMG-Groton, Connecticut

THIS PAGE INTENTIONALLY BLANK

AECOM 6-12
B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 6-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/15/2022

12/15/2022

12/15/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/15/2022

1:3,600

Facility Location

Water Body

Wetland

River/Stream

PFOA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

Shallow Intermediate Deep

Exceedances of the OSD SL are depicted with a yellow halo.

Depth intervals shown represent respective sampling position within a given soil boring location.

PFOA Results (μg/Kg)

ND

>ND - 19

>19 - 250

>250 - 2,500

>2,500

0 150 300 600

Feet

AECOM 6-13
B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 6-2

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/15/2022

12/15/2022

12/15/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/15/2022

1:3,600

Facility Location

Water Body

Wetland

River/Stream

PFOS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

Shallow Intermediate Deep

Exceedances of the OSD SL are depicted with a yellow halo.

Depth intervals shown represent respective sampling position within a given soil boring location.

PFOS Results (μg/Kg)

ND

>ND - 13

>13 - 160

>160 - 1,600

>1,600

0 150 300 600

Feet

AECOM 6-14
B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 6-3

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/15/2022

12/15/2022

12/15/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/15/2022

1:3,600

Facility Location

Water Body

Wetland

River/Stream

PFBS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

Shallow Intermediate Deep

Exceedances of the OSD SL are depicted with a yellow halo.

Depth intervals shown represent respective sampling position within a given soil boring location.

PFBS Results (μg/Kg)

ND

>ND - 10

>10 - 1,900

>1,900 - 25,000

>25,000

0 150 300 600

Feet

AECOM 6-15
B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 6-4

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/15/2022

12/15/2022

12/15/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/15/2022

1:3,600

Facility Location

Water Body

Wetland

River/Stream

PFHxS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

Shallow Intermediate Deep

Exceedances of the OSD SL are depicted with a yellow halo.

Depth intervals shown represent respective sampling position within a given soil boring location.

PFHxS Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

0 150 300 600

Feet

AECOM 6-16
B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 6-5

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/15/2022

12/15/2022

12/15/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/15/2022

1:3,600

Facility Location

Water Body

Wetland

River/Stream

PFNA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

Shallow Intermediate Deep

Exceedances of the OSD SL are depicted with a yellow halo.

Depth intervals shown represent respective sampling position within a given soil boring location.

PFNA Results (μg/Kg)

ND

>ND - 19

>19 - 250

>250 - 2,500

>2,500

0 150 300 600

Feet

AECOM 6-17
B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02 AOI02-03

AOI03-01

­ Figure 6-6

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

12/15/2022

12/15/2022

12/15/2022

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

12/15/2022

1:3,600

Facility Location

Water Body

Wetland

River/Stream

Groundwater Flow Direction

PFOA, PFOS, and PFBS Detections in Groundwater

12420 Milestone Center Drive

Germantown, MD 20876

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

B irch Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

PFOA PFOS PFBS

Exceedances of the OSD SL are depicted with a yellow halo.

0 150 300 600

Feet

PFOA Results (ng/L)

ND

>ND - 6

>6 - 40

>40 - 70

>70

PFOS Results (ng/L)

ND

>ND - 4

>4 - 40

>40 - 70

>70

PFBS Results (ng/L)

ND

>ND - 100

>100 - 601

>601 - 2,000

>2,000

AECOM 6-18
B irch

Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

­ Figure 6-7

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at TASMG Groton, CT

2/23/2023

2/23/2023

2/23/2023

MS

JW

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, Earthstar Geographics, and the GIS User Community

2/23/2023

1:3,600

Facility Location

Water Body

Wetland

River/Stream

Groundwater Flow Direction

PFHxS and PFNA Detections in Groundwater

12420 Milestone Center Drive

Germantown, MD 20876

B irch

Creek

TMG-03

AOI01-02

AOI01-01

AOI01-03

TMG-02

AOI01-04

TMG-01

AOI02-01

AOI02-02

AOI02-03

AOI03-01

PFHxS PFNA

Exceedances of the OSD SL are depicted with a yellow halo.

0 150 300 600

Feet

PFHxS Results (ng/L)

ND

>ND - 39

>39 - 100

>100 - 1,000

>1,000

PFNA Results (ng/L)

ND

>ND - 6

>6 - 100

>100 - 1,000

>1,000

AECOM 6-19
Site Inspection Report

1109th TASMG-Groton, Connecticut

THIS PAGE INTENTIONALLY BLANK

AECOM 6-20
Site Inspection Report

1109th TASMG-Groton, Connecticut

AECOM 7-1

7. Exposure Pathways

The CSM for each AOI, revised based on the SI findings, is presented on Figure 7-1. Please note 

that while the CSM discussion assists in determining if a receptor may be impacted, the decision 

to move from SI to RI or interim action is determined based upon exceedances of the SLs for the 

relevant compounds and whether the release is more than likely attributable to the DoD. A CSM 

presents the current understanding of the site conditions with respect to known and suspected 

sources, potential transport mechanisms and migration pathways, and potentially exposed human 

receptors. A human exposure pathway is considered potentially complete when the following 

conditions are present:

1. Contaminant source;

2. Environmental fate and transport;

3. Exposure point;

4. Exposure route; and

5. Potentially exposed populations.

If any of these elements are missing, the pathway is incomplete. The CSM figures use an empty 

circle symbol to represent an incomplete exposure pathway. Areas with an incomplete pathway 

generally warrant no further action. However, the pathway is considered potentially complete if the 

relevant compounds are detected, in which case the CSM figure uses a half-filled circle symbol to 

represent a potentially complete exposure pathway. Additionally, a completely filled circle symbol is 

used to indicate when a potentially complete exposure pathway has detections of relevant 

compounds above the SLs. Areas with an identified potentially complete pathway that have 

detections of the relevant compounds above the SLs may warrant further investigation. Although 

the CSMs indicate whether potentially complete exposure pathways may exist, the 

recommendation for future study in an RI or no action at this time is based on the comparison of 

the SI analytical results for the relevant compounds to the SLs.

In general, the potential routes of exposure to the relevant compounds are ingestion and 

inhalation. Human exposure via the dermal contact pathway may occur, and current risk practice 

suggests it is an insignificant pathway compared to ingestion; however, exposure data for dermal 

pathways are sparse and continue to be the subject of toxicological study. The receptors 

evaluated are consistent with those listed in USEPA guidance for risk screening (USEPA, 2001). 

Receptors at the facility include site workers (e.g., facility staff and visiting soldiers), construction 

workers, trespassers (though unlikely due to restricted access), residents outside the facility 

boundary, and recreational users outside of the facility boundary.

7.1 Soil Exposure Pathway

The SI results in soil were used to determine whether a potentially complete pathway exists 

between the source and potential receptors at AOI 1, AOI 2, and AOI 3 based on the 

aforementioned criteria.

7.1.1 AOI 1

AOI 1 is Building 320, the Main Hangar at TASMG-Groton where AFFF-laden water may have 

been released to the building perimeter during the AFFF fire suppression system test events 

between 2008 and the present. Landscaped areas exist adjacent to Building 320. Surface soil in 

the landscaped areas near Building 320 may have received surface water runoff containing AFFF 

constituents as a result of spillage at the test ports during system testing.
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AECOM 7-2

PFOA, PFOS, PFBS, PFHxS, and PFNA were detected in surface soil at AOI 1 as well as the 

side-gradient sample location TMG-03 below their respective SLs. Site workers, future 

construction workers, and trespassers could contact constituents in surface soil via incidental 

ingestion and inhalation of dust. There was no active construction occurring at the time of the SI. 

Therefore, the surface soil exposure pathway for site workers, future construction workers, and 

trespassers are potentially complete. Residential areas exist within 0.5 miles of the facility to the 

north, west, and southwest of the facility; therefore, the exposure pathway for off-facility residents 

via inhalation of dust is also considered potentially complete. PFOA, PFOS, PFBS, PFHxS, and 

PFNA were also detected in subsurface soil at AOI 1 below their respective SLs. Potential future 

construction workers could contact constituents in subsurface soil via incidental ingestion;

therefore, the subsurface soil exposure pathway for construction workers is potentially complete. 

The CSM for AOI 1 is presented on Figure 7-1. 

7.1.2 AOI 2

AOI 2 is Building 323, the Engine Shop, where AFFF releases occurred during fire suppression 

system discharges circa 2010-2012 and 2014. During the events, AFFF drained to the interior 

building floor drains that connect to an OWS but could have also escaped the building through 

the garage door or beneath entryway doors. Landscaped and wooded areas exist adjacent to 

Building 323. Surface soil in these may have received AFFF flowing outwardly from the building 

or surface water runoff containing AFFF as a result of the releases.

PFOA, PFOS, PFBS, and PFNA were detected in surface soil at AOI 2 below their respective 

SLs. PFOS and PFNA were also detected in surface soil at the potentially upgradient location 

TMG-01 and downgradient location TMG-02 below their respective SLs. Location TMG-01 is 

upgradient of groundwater flow from AOI 2; however, it may be downgradient of surface runoff 

from the AOI. Site workers and future construction workers could contact constituents in surface 

soil via incidental ingestion and inhalation of dust. Therefore, the surface soil exposure pathway 

for site workers, future construction workers, and trespassers are potentially complete. The 

exposure pathway for off-facility residents via inhalation of dust is also considered potentially 

complete, as described in Section 7.1.1. PFOA, PFOS, PFBS, PFHxS, and PFNA were also 

detected in shallow subsurface soil at AOI 2. Additionally, PFOA, PFOS, PFHxS, and PFNA were 

detected in shallow subsurface soil between TMG-01 and TMG-02. All detected concentrations 

were below the respective SLs. Potential future construction workers could contact constituents 

in subsurface soil via incidental ingestion, and therefore, the subsurface soil exposure pathway 

for construction workers is potentially complete. The CSM for AOI 2 is presented on Figure 7-1. 

7.1.3 AOI 3

AOI 3 consists of Building 325 and its adjacent storage area where potentially AFFF-laden water 

generated from the test ports at Building 320 is temporarily stored in barrels prior to disposal. The 

storage area is unsheltered, and barrels are subject to corrosion due to the elements. It is also 

possible that spillage may occur to the nearby grassy and paved surfaces.

PFOS and PFNA were detected in surface soil at AOI 3 below their respective SLs. Site workers 

and future construction workers could contact constituents in surface soil via incidental ingestion 

and inhalation of dust. Therefore, the surface soil exposure pathway for site workers, construction 

workers, and trespassers are potentially complete. The exposure pathway for off-facility residents 

via inhalation of dust is also considered potentially complete, as described in Section 7.1.1. PFOS 

and PFNA were detected in subsurface soil at AOI 3 below their respective SLs. Construction 

workers could contact constituents in subsurface soil via incidental ingestion, and therefore, the 

subsurface soil exposure pathway for construction workers is potentially complete. The CSM for 

AOI 3 is presented on Figure 7-1.
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AECOM 7-3

7.2 Groundwater Exposure Pathway

The SI results in groundwater were used to determine whether a potentially complete pathway 

exists between the source and potential receptors based on the aforementioned criteria.

7.2.1 AOI 1

PFOA, PFOS, and PFNA were detected above their SLs in groundwater samples collected at AOI 

1, and PFOS was detected above its SL at the side-gradient location TMG-03. The groundwater 

underlying TASMG-Groton and the larger surrounding airport area is designated as “class GB” by 

the CTDEEP, which indicates the groundwater is assumed to be degraded due to likely pollution 

sources, and it is not suitable for human consumption without treatment (CAA, 2013). Due to the 

groundwater designation as class GB, the pathway for exposure to off-facility residents via 

ingestion of groundwater is considered incomplete. The facility is supplied drinking water by the 

Groton Utilities Water Operations, and there are no potable water wells at the facility. Depths to 

water measured at AOI 1 in May 2022 during the SI ranged from 7.35 to 9.52 feet bgs. Therefore,

the ingestion exposure pathway for future construction workers is considered potentially 

complete. The CSM for AOI 1 is presented on Figure 7-1. 

7.2.2 AOI 2

PFOA, PFOS, and PFNA were detected above their SLs in groundwater samples collected at AOI 

2; and PFOA and PFOS were detected above their SLs in groundwater samples collected at the 

downgradient location TMG-02. No relevant compounds were detected above their SLs in 

groundwater at the upgradient location TMG-01. The pathway for exposure to off-facility residents 

and site workers via ingestion of groundwater is considered incomplete for the reasons described 

in Section 7.2.1. Depths to water measured in May 2022 during the SI ranged from 1.12 to 8.19

feet bgs. Therefore, the ingestion exposure pathway for future construction workers is considered 

potentially complete. The CSM for AOI 2 is presented on Figure 7-1. 

7.2.3 AOI 3

PFOS was detected above its SL in the groundwater sample collected at AOI 3. The pathway for 

exposure to off-facility residents and site workers via ingestion of groundwater is considered 

incomplete for the reasons described in Section 7.2.1. Depth to water measured in May 2022 

during the SI at AOI 3 was 8.77 feet bgs. Therefore, the ingestion exposure pathway for future 

construction workers is considered potentially complete. The CSM for AOI 3 is presented on 

Figure 7-1.

7.3 Surface Water and Sediment Exposure Pathway

The SI results in soil and groundwater, in combination with knowledge of the fate and transport 

properties of PFAS, were used to determine whether a potentially complete pathway exists 

between the source and potential receptors. No surface water or sediment samples were 

collected during the SI. 

7.3.1 AOI 1

Catch basins located near Building 320 channel surface runoff west to a wetland area that is 

associated with Birch Creek, which flows to Baker Cove and the Long Island Sound. In general, 

surface runoff at the facility drains west towards the Birch Creek. It is possible that AFFF-laden 

water could have entered the catch basins during fire suppression system testing at AOI 1. 

Additionally, a stormwater outlet pipe also conveys runoff to an area on the northwestern border 
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AECOM 7-4

of the facility filled with cattails and other vegetation associated with wetlands. PFAS are water 

soluble and can migrate readily from soil to surface water via leaching and run-off.

Because PFOA, PFOS, PFBS, PFHxS, and PFNA were detected in soil and groundwater at AOI 

1, it is possible that those compounds may have migrated via runoff from soil and groundwater to 

the wetland on the northwestern facility border and to the wetlands west of the facility. Therefore, 

the surface water and sediment ingestion exposure pathway for site workers, future construction 

workers, or trespassers is considered potentially complete. The surface water and sediment 

ingestion exposure pathway is also considered potentially complete for recreational users of the 

surface water bodies downgradient from AOI 1, such as Birch Creek and Baker Cove. The CSM 

for AOI 1 is presented on Figure 7-1. 

7.3.2 AOI 2 

During fire suppression system releases at AOI 2, AFFF could have migrated from the building 

towards the non-delineated wetland area located approximately 180 feet northeast (at the 

northwestern border of the facility) or west towards Birch Creek. Because PFOA, PFOS, PFBS, 

PFHxS, and PFNA were detected in soil and groundwater at AOI 2 and associated locations TMG01 and TMG-02, it is possible that those compounds may have migrated via runoff from soil and 

groundwater to the wetland on the northwestern facility border and to the wetlands west of the 

facility. Therefore, the surface water and sediment ingestion exposure pathway for site workers, 

future construction workers, or trespassers is considered potentially complete. The surface water 

and sediment ingestion exposure pathway is also considered potentially complete for recreational 

users of the surface water bodies downgradient from AOI 2. The CSM for AOI 2 is presented on 

Figure 7-1. 

7.3.3 AOI 3 

Surface runoff at AOI 3 may flow southeast or northwest if spillage occurs, and runoff to the 

northwest could reach Birch Creek or the wetland on the northwest border of the facility. Because

PFOS and PFNA were detected in soil, and PFOA, PFOS, PFBS, PFHxS, and PFNA were 

detected in groundwater at AOI 3, it is possible that those compounds may have migrated via 

runoff from soil and groundwater to the wetland on the northwestern facility border and to the 

wetlands west of the facility. Therefore, the surface water and sediment ingestion exposure 

pathway for site workers, future construction workers, or trespassers is considered potentially 

complete. The surface water and sediment ingestion exposure pathway is also considered 

potentially complete for recreational users of the surface water bodies downgradient from AOI 3. 

The CSM is presented on Figure 7-1. 
Media

SOURCE PATHWAY RECEPTOR

AOI 1 - AOI 3

Fire suppression 

system releases, 

and AFFF-laden

water storage

Surface 

Soil / Paved 

Surfaces

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ 

Infiltration

Airborne Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Source Release 

Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors: 

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Incomplete Pathway

Potentially Complete Pathway

Potentially Complete Pathway 

with Exceedance of SL

Site Worker Construction Worker3 Resident1,2

Site Worker Construction Worker3 Resident1,2

/ / / /

/ / / /

LEGEND

/ / / /

/ / / /

/ / / /

Figure 7-1

Conceptual Site Model, AOI 1 – AOI 3

TASMG-Groton, CT

Potential 

Off-Facility 

Source Not 

Under 

Control of 

ARNG

Tresspasser/ Recreational User1,2

Tresspasser/ Recreational User1,2 Flow-Chart Stops Notes:

1. The resident and recreational users refer to offsite receptors.

2. Inhalation of dust for off-site receptors is likely

insignificant.

3. No current active construction at the facility.

AECOM 7-5 
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AECOM 7-6

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AECOM 8-1

8. Summary and Outcome

This section summarizes SI activities and findings. The most significant findings are summarized 

in this section and are reproduced directly or abstracted from information contained in this report. 

The outcome provides general and comparative interpretations of the findings relative to the SLs.

8.1 SI Activities

The SI field activities were conducted from 12 to 19 May 2022 and consisted of utility clearance, 

direct push boring, soil sample collection, temporary monitoring well installation and subsequent 

abandonment, grab groundwater sample collection, and land surveying. Field activities were 

conducted in accordance with the SI QAPP Addendum (AECOM, 2021a). 

To fulfill the project DQOs set forth in the approved SI QAPP Addendum (AECOM, 2021a), samples 

were collected and analyzed for a subset of 18 compounds by LC/MS/MS compliant with QSM 5.3 

Table B-15 as follows. 

• Thirty-three (33) soil samples from 11 boring locations; 

• Eleven (11) grab groundwater samples from 11 temporary well locations; 

• Nineteen (19) quality assurance QA/QC samples.

An SI is conducted when the PA determines an AOI exists based on probable use, storage, and/or 

disposal of PFAS-containing materials. The SI includes multi-media sampling at AOIs to 

determine whether or not a release has occurred. The SI may conclude further investigation is 

warranted, a removal action is required to address immediate threats, or no further action is 

required. Additionally, the CSM was refined to assess whether a potentially complete pathway 

exists between the source and potential receptors for potential exposure at the AOIs, which are 

described in Section 7.

8.2 Outcome 

Based on the results of this SI, further evaluation is warranted in an RI for AOI 1, AOI 2, and AOI 

3. Based on the CSM developed and revised in light of the SI findings, there is no potential for 

exposure to drinking water receptors, aside from potential future construction workers, due to

historical DoD activities at the facility. Sample analytical concentrations collected during the SI 

were compared against the project SLs in soil and groundwater, as described in Table 6-1. A 

summary of the results of the SI data relative to the SLs is as follows:

• At AOI 1:

• The detected concentrations of PFOA, PFOS, PFBS, PFHxS, and PFNA in soil at 

AOI 1 and TMG-03 were below their SLs. 

• PFOA, PFOS, and PFNA in groundwater exceeded their SLs. PFOA exceeded the 

SL of 6 ng/L, with a maximum concentration of 8.20 ng/L at location AOI01-04. PFOS 

exceeded the SL of 4 ng/L, with a maximum concentration of 53.8 ng/L at location 

AOI01-04. PFNA exceeded the SL of 6 ng/L, with a maximum concentration of 6.89 

ng/L at location AOI01-04. Additionally, PFOS exceeded its SL at side-gradient 

location TMG-03, with a concentration of 9.91 ng/L. Based on the exceedances of 

SLs, further evaluation of AOI 1 is warranted in an RI.
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AECOM 8-2

• At AOI 2:

• The detected concentrations of PFOA, PFOS, PFBS, PFHxS, and PFNA in soil at

AOI 2, TMG-01 and TMG-02, were below their SLs.

• PFOA, PFOS, and PFNA in groundwater exceeded their SLs. PFOA exceeded the

SL of 6 ng/L, with a maximum concentration of 143 ng/L at location AOI02-01. PFOS

exceeded the SL of 4 ng/L, with a maximum concentration of 11.8 ng/L at location

AOI02-03. PFNA exceeded the SL of 6 ng/L, with a maximum concentration of 18.5

ng/L at location AOI02-02. Additionally, PFOA and PFOS exceeded their SLs at

downgradient location TMG-02, with concentrations of 10.58 ng/L and 15.0 ng/L,

respectively. No analytes exceeded SLs at upgradient location TMG-01. Based on

the exceedances of SLs, further evaluation of AOI 2 is warranted in an RI.

• At AOI 3:

• The detected concentrations of PFOS and PFNA in soil at AOI 3 were below their

SLs.

• PFOS in groundwater exceeded the SL of 4 ng/L, with a concentration of 9.89 ng/L

at AOI03-01. Based on the exceedance of SLs, further evaluation of AOI 3 is

warranted in an RI.

Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA 

(commonly referred to as GenX) was not included as an analyte at the time of this SI. Based on 

the CSM developed during the PA and revised based on SI findings, the presence of HFPO-DA 

is not anticipated at the facility because HFPO-DA is generally not a component of MIL-SPEC 

AFFF and based on its history including distribution limitations that restricted use of GenX, it is 

generally not a component of other products the military used. In addition, it is unlikely that GenX 

would be an individual chemical of concern in the absence of other PFAS. 

Table 8-1 summarizes the SI results for soil and groundwater used to determine if an AOI should 

be considered for further investigation under CERCLA and undergo an RI. 

Table 8-1: Summary of Site Inspection Findings and Recommendations

AOI Potential 

Release Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater –

Facility 

Boundary

Future Action

1 Building 320 – 

Main Hangar N/A Proceed to RI 

2 Building 323 – 

Engine Shop Proceed to RI 

3

Building 325 – 

State Equipment 

Storage Building

N/A Proceed to RI

Legend:

N/A = not applicable

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected
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AECOM 9-1

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