FINAL

Site Inspection Report 

Martindale Army Aviation 

Support Facility

San Antonio, Texas

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 

September 2023 

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED

Site Inspection Report

Martindale AASF, San Antonio, Texas

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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 ...............................................................................................2-1

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

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

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 ...............................................................................................2-3

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

3.1 AOI 1 Grass Fire Near Flight Line...........................................................................3-1

3.2 AOI 2 Area East of the Maintenance Hangar..........................................................3-1

3.3 AOI 3 Wash Rack ...................................................................................................3-1

3.4 Adjacent Sources....................................................................................................3-1

3.4.1 Republic Services Landfill ............................................................................3-1

3.4.2 Flint Hills Resources Gas Storage Facility ...................................................3-2

3.4.3 AZZ Galvanizing San Antonio.......................................................................3-2

3.4.4 Blue Beacon Truck Wash .............................................................................3-2

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

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

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........................................................................................6-3

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

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 ............................................................................7-2

7.2.1 AOI 1, AOI 2, and AOI 3 ...............................................................................7-3

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

7.3.1 AOI 1, AOI 2, AOI 3 ......................................................................................7-3

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. Nonconformance and Corrective Action Reports

B5. 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, April 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 and AOI 3

Figure 7-2 Conceptual Site Model, AOI 2

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 Deep Subsurface Soil

Table 6-5 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

AASF Army Aviation Support Facility

AECOM AECOM Technical Services, Inc.

AFFF aqueous film-forming foam

AOI Area of Interest

ARNG Army National Guard

ASTM American Society for Testing and Materials

bgs below ground surface 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CoC chain of custody

CSM conceptual site model

DA Department of the Army

DoD Department of Defense

DOT Department of Transportation

DPT direct push technology

DQO data quality objective

DUA data usability assessment

EIS extraction internal standards

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

FedEx Federal Express

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

MS matrix spike

MSD matrix spike duplicate

NELAP National Environmental Laboratory Accreditation Program

ng/L nanograms per liter

OMS Organizational Maintenance Shop

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

RI Remedial Investigation

SI Site Inspection

SL screening level

SOP standard operating procedure

TBWE Texas Board of Water Engineers

TOC total organic carbon

TPP Technical Project Planning

UFP Uniform Federal Policy

US United States

USACE United States Army Corps of Engineers

USACHPPM US Army Center for Health Promotion and Preventive Medicine

USCS Unified Soil Classification System

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service
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Martindale AASF, San Antonio, Texas

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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. 

A PA was completed at Martindale Army Aviation Support Facility (AASF) that 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 Martindale AASF in San Antonio, Texas and determined further evaluation 

under the Comprehensive, Environmental Response, and Liability Act (CERCLA) is warranted for 

each of the three AOIs. The Martindale AASF will also be referred to as the “facility” throughout 

this document.

Martindale AASF is located within the San Antonio city limits, southeast of the intersection of 

Interstate 10 and Interstate 410. The facility comprises approximately 220 acres of mostly 

grassland, as well as a storage hangar, maintenance hangar, armory, and flight lines. The facility 

was opened by the United States Air Force in 1943 for the purpose of training and was restricted 

to take offs and landings. The property deed was transferred from the United States Air Force to 

the ARNG in 1954.

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 (RI) for each of the three AOIs.

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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Martindale AASF, San Antonio, Texas

AECOM ES-2

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

Grass Fire 

Near Flight 

Line

Proceed to RI 

2

Area East of 

the 

Maintenance 

Hangar

N/A Proceed to RI

3 Wash Rack Proceed to RI

Legend:

N/A = not applicable 

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected

1 
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Martindale AASF, San Antonio, Texas

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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 Martindale Army 

Aviation Support Facility (AASF) in San Antonio, Texas. The Martindale AASF is also 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 Martindale AASF (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

Martindale AASF is located within the San Antonio city limits, southeast of the intersection of 

Interstate 10 and Interstate 410. The facility is located 7 miles east of downtown San Antonio 

(Figure 2-1). The facility comprises approximately 220 acres of mostly grassland, as well as a 

storage hangar, maintenance hangar, armory, and flight lines (US Army Center for Health 

Promotion and Preventive Medicine [USACHPPM], January 1997). The facility was opened by 

the US Air Force in 1943 for the purpose of training and was restricted to take offs and landings. 

The property deed was transferred from the US Air Force to the ARNG in 1954. Most of the 

buildings were constructed in the early 1960s except for the current Organizational Maintenance 

Shop (OMS) built in 1991, the Storage Hangar built in 2004, and additional facility support 

buildings built from 2010 to 2012. 

2.2 Facility Environmental Setting

Martindale AASF is located in Bexar County, south-central Texas, approximately 140 miles 

northwest of the Gulf of Mexico. The facility is about 10 miles northwest of Calaveras Lake and 

less than 1 mile west of Rosillo Creek. The 220-acre facility is located within the San Antonio city 

limits, east of the city center (Figure 2-2). Industrial/commercial properties lie to the north, with 

Interstate 10 beyond. West and southwest of the facility are predominately single-family homes, 

with Interstate 410 beyond. East of the facility, in the area stretching between Interstate 10 and E 

Houston Street, a planned industrial park is currently under construction. South of the facility is 

mostly undeveloped property and industrial industries including a cemetery, recycling center, and 

a galvanizing company; E. Houston Street lies beyond these properties. Some nearby industrial 

facilities represent potential PFAS sources. 

2.2.1 Geology

The facility is underlain by fluviatile terrace deposits of the Quaternary period consisting of gravel, 

sand, silt and clay. The fluviatile terrace deposits are underlain by the Midway Group consisting 

of clay and sand deposited in the Tertiary period (Figure 2-3) (USACHPPM, 1997). The Edwards 

Limestone outcrops about 10 miles to the north-northwest of the facility, on the upward shifted 

side of significant northeast–southwest trending normal faults (Bureau of Economic Geology, 

1982). The facility lies on the downward-shifted side of this fault zone and therefore has several 

hundred feet of younger Quaternary, Tertiary and Upper Cretaceous geologic units overlying the 

Edwards Limestone (Texas Board of Water Engineers [TBWE], 1959). 

During the SI, lean clay was observed as the dominant lithology of the unconsolidated sediments 

below the Martindale AASF. The borings were completed at depths between 20 and 33.5 feet 

below ground surface (bgs). Isolated layers of sand and silt were also observed in the borings 

with thicknesses ranging from a few inches to 5 feet. The facility observations are consistent with 

the reported depositional environment of the region. Boring logs are presented in Appendix E.

2.2.2 Hydrogeology

The Edwards Limestone is the sole-source aquifer for the San Antonio area, and San Antonio 

obtains its entire water supply from this aquifer. The presence of a fault zone coupled with the 

high degree of fracturing in the limestone results in a complex flow pattern. The top of the Edwards 

aquifer is bounded by an upper confining layer that results in artesian conditions. The nearest 

water supply well is approximately 1.5 miles north of the facility. The well is reported as 1,139 feet 
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deep and supplies the City of Kirby. Shallower water-bearing zones are most likely discontinuous 

perched lenses and not used as a drinking water supply in the San Antonio area (USACHPPM, 

1997). Shallow unconfined groundwater would normally follow the local topography, which is to 

the southeast, towards Rosillo Creek. 

No wells exist at the facility. An exploratory boring was drilled on 8 July 1988 to provide information 

to bidders on a contract to construct the OMS building. The borehole extended to a depth of 20.5 

feet, and it remained open for at least 3 days, at which time the groundwater level was measured 

at 15.8 feet bgs. There are no data available on the behavior of this uppermost water-bearing 

zone at the facility. The shallow groundwater is not used as a drinking water supply in the San 

Antonio area and is probably a discontinuous perched lens with little or no interconnection with 

the Edwards aquifer (USACHPPM, 1997). The general groundwater flow in the Edwards aquifer 

in San Antonio is to the southeast (TBWE, 1954).

A query of the Texas Water Development Board’s Interactive Groundwater Data Viewer identified 

71 monitoring wells and 92 environmental soil boring records within a 1-mile radius of the center 

of the facility (Figure 2-3). The monitoring wells directly north of the facility are owned by Travel 

Centers of America, and NuStar Logistics LP owns 13 monitoring wells approximately 0.8 miles 

northeast of the facility. Midtex Oil, LP and CCC Group own 18 monitoring wells approximately 

0.8 miles north-northeast of the facility. Other monitoring wells located within a 1-mile radius of 

the facility are owned by LIT Industrial Texas, LP, Southwest Galvanizing, Summit Truck Group, 

and York International Corp., among others. The facility’s drinking water is supplied by the City of 

San Antonio. 

Depths to water measured in April 2022 during the SI ranged from 9.12 to 25.62 feet bgs. 

Groundwater elevation contours from the SI are presented on Figure 2-4 and indicate the 

groundwater flow direction within the shallow aquifer at Martindale AASF is generally to the southsoutheast. Locations AOI02-04 and AOI03-02 were excluded from contouring as discussed in 

Section 5.8.

2.2.3 Hydrology

Surface water at the facility flows through ditches around the perimeter of the flight line to the 

southeast and settles in a retention pond in the southeast corner of the facility. The retention pond 

is less than 2,000 feet from Rosillo Creek, so it is likely that surface water flows from the retention 

pond to the creek under heavy rain conditions. 

Wastewater that collects in the wash rack flows to an oil-water separator (OWS) and then, 

depending on the position of a diverter valve, either travels through underground piping to the 

sanitary sewer, or goes through a series of manholes before discharging to Rosillo Creek and 

then Salado Creek. Surface water features are presented on Figure 2-5.

2.2.4 Climate

The San Antonio climate is humid subtropical, with long, hot summers and warm to cool winters. 

Cold fronts from the north occasionally descend during the winters and affect the weather 

conditions. The average high temperature is around 96 degrees Fahrenheit (°F) in the peak of 

August (National Weather Service Forecast Office, 2022). Winters range from mild to cool, with 

the average daily highs rarely dropping below 60 °F. The spring and autumn months tend to be 

warm and wet. The average humidity in San Antonio is around 67 percent (%). San Antonio is 

usually sunny, with average annual precipitation around 32 inches. May, September, and October 

tend to be the rainiest months. Snowfall is rare in San Antonio, but the area occasionally

experiences sleet and freezing rain. Floods occur regularly, and tornados occasionally occur in 

the region (Weather Atlas, 2022). 
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2.2.5 Current and Future Land Use

The Martindale AASF currently includes temporary and permanent storage buildings, an OMS 

building, two hangars, and an armory used for administration. Current land use in the direct vicinity 

of the facility includes undeveloped/agricultural land to the east, residential land to the west, and 

commercial/industrial land to the north and south. Historically, undeveloped land surrounding the 

facility was leased to a farmer who grew corn until sometime between 2016 and 2017. No future 

changes to the current use were noted during personnel interviews.

2.2.6 Sensitive Habitat and Threatened/ Endangered Species 

The following arachnids, birds, crustaceans, fishes, plants, insects, and mammals are federally

endangered, threatened, proposed, and/ or are listed as candidate species in Bexar County, 

Texas (US Fish and Wildlife Service [USFWS], 2022). 

• Arachnids: Government Canyon Bat Cave spider, Tayshaneta microps (endangered); 

Madla Cave Meshweaver, Cicurina madla (endangered); Robber Baron Cave Meshweaver, 

Cicurina baronia (endangered); Cokendolpher Cave Harvestman, Texella cokendolpheri

(endangered); Government Canyon Bat Cave meshweaver, Cicurina vespera (endangered)

• Birds: Whooping crane, Grus americana (endangered); Red knot, Calidris canutus rufa 

(threatened); Golden-cheeked warbler, Setophaga chrysoparia (endangered); Piping 

Plover, Charadrius melodus (threatened); 

• Crustaceans: Peck's cave amphipod, Stygobromus (=Stygonectes) pecki (endangered)

• Fishes: Fountain darter, Etheostoma fonticola (endangered)

• Flowering Plants: Black lace cactus, Echinocereus reichenbachii var. albertii

(endangered); Texas wild-rice, Zizania texana (endangered); Bracted twistflower, 

Streptanthus bracteatus (proposed threatened)

• Insects: Monarch butterfly, Danaus plexippus (candidate); Comal Springs riffle beetle, 

Heterelmis comalensis (endangered); [no common name] Beetle, Rhadine exilis

(endangered); Helotes mold beetle, Batrisodes venyivi (endangered); Comal Springs 

dryopid beetle, Stygoparnus comalensis (endangered); [no common name] Beetle, Rhadine 

infernalis (endangered)

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

2.3 History of PFAS Use

Three AOIs were identified in the PA where AFFF may have been used, stored, disposed, or 

released historically at the Martindale AASF (AECOM, 2020). Sometime between 1999 and 2014, 

AFFF was used to put out a grass fire near the flightline. Additionally, AFFF may have historically 

been released at the facility during Tri-MaxTM maintenance events and incidental spills due to 

storage of a firetruck. The potential release areas were grouped into three AOIs based on 

preliminary data and presumed groundwater flow directions. A description of each AOI is 

presented in Section 3.
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PROJECT Site Inspection at Martindale AASF, TX

1:63,360

1/20/2023 ­ Figure 2-1 PM CM 1/20/2023

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 Boundary

0 0.5 1 2

Miles

^_

Martindale AASF

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PROJECT Site Inspection at Martindale AASF, TX

1:12,000

3/2/2023 ­ Figure 2-2 PM CM 3/2/2023

12420 Milestone Center Drive

Germantown, MD 20876

Facility Topography

Base Map: USGS The National Map: National

Boundaries Dataset, 3DEP Elevation Program,

Legend

Facility Boundary

0 500 1,000 2,000

Feet

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AECOM 3-1

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, four potential release areas were

identified at Martindale AASF and grouped into three AOIs (AECOM, 2020). The potential release

areas are shown on Figure 3-1.

3.1 AOI 1 Grass Fire Near Flight Line

AFFF was used to put out a grass fire near the southwest end of the flight line during one event 

that took place between 1999 and 2014. An unknown quantity of AFFF was released during this 

emergency firefighting response. Releases at the grassy areas on either side of the flight line 

would impact surface soil and potentially infiltrate to the subsurface and groundwater via rainwater 

leaching.

3.2 AOI 2 Area East of the Maintenance Hangar

AFFF was potentially released at the area east of the Maintenance Hangar during Tri-MaxTM

maintenance events performed by an outside contractor. The AFFF fluids stored in the Tri-MaxTM

units were disposed of during these maintenance events. Additionally, a firetruck, which was 

historically stored further east of the Maintenance Hangar, likely contained AFFF tanks, and AFFF 

could have leaked on to the gravel surface beneath the truck. 

Releases at the area east of the Maintenance Hangar may have infiltrated into surrounding grassy 

areas when washed off the concrete surface, and potential releases at the firetruck may have 

infiltrated into the gravel and soil beneath it. Releases in either area have the potential to leach

into the subsurface and shallow groundwater during precipitation events.

3.3 AOI 3 Wash Rack

AFFF was potentially released at the wash rack during Tri-MaxTM maintenance events performed 

by an outside contractor. The AFFF fluids stored in the Tri-MaxTM units would have been disposed 

of during these maintenance events when old AFFF was replaced with new AFFF in the units. 

Releases at the wash rack would have traveled to the OWS and then, depending on the position 

of a diverter valve, either traveled through underground piping to the sanitary sewer, or traveled 

through a series of manholes before discharging to Rosillo Creek and then to Salado Creek. 

Releases at the wash rack have the potential to infiltrate into soil and further into the subsurface 

via leaks in underground piping.

3.4 Adjacent Sources

Four off-facility potential sources were identified adjacent to the Martindale AASF during the PA 

and are not associated with ARNG activities. The adjacent potential sources are shown on Figure 

3-1 and described in the following sections for informational purposes only and were not 

investigated as part of this SI.

3.4.1 Republic Services Landfill

The Republic Services Landfill is located about 2 miles east of the facility. This landfill could be a 

potential source of PFAS, but it is located cross-gradient of the facility. Landfills are not usually a 

primary release area of PFAS, but materials disposed in landfills may create a secondary source 
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AECOM 3-2

of contamination. Such materials may include sludge from a wastewater treatment plant that 

processes PFAS-laden water, used AFFF storage containers, or products associated with 

waterproofing such as uniforms or boots.

3.4.2 Flint Hills Resources Gas Storage Facility

Flint Hills Resources gas storage facility is located cross-gradient, approximately 5,000 feet 

southwest of the Martindale AASF. A gas storage facility may have and use AFFF on-site because 

of the need to have effective firefighting capabilities at facilities with large quantities of bulk fuel. 

3.4.3 AZZ Galvanizing San Antonio

AZZ Galvanizing is located downgradient, approximately 1,040 feet south-southeast of the facility. 

AZZ Galvanizing is a large quantity generator as defined by USEPA, meaning that it generates 

over 1,000 kilograms of hazardous waste, or over 1 kilogram of acutely hazardous waste per 

month. A hazardous waste summary for AZZ Galvanizing describes it as having ignitable waste, 

corrosive waste, arsenic, cadmium, chromium, lead, and selenium waste. The processes 

conducted at AZZ Galvanizing are described as metal coating and allied services. The process of 

metal plating and etching is known to use PFAS for corrosion prevention, mechanical wear 

reduction, aesthetic enhancement, surfactant, wetting agent/fume suppressant for chrome, 

copper, nickel, and tin electroplating, and post-plating cleaner (Interstate Technology Regulatory 

Council [ITRC], 2017). It is possible that the processes conducted at AZZ Galvanizing include the 

use of PFAS. 

3.4.4 Blue Beacon Truck Wash

Blue Beacon Truck Wash of San Antonio is located at 1112 Ackerman Road in San Antonio, 

upgradient and directly north of the facility. The Truck Wash shares the northern boundary of the 

facility. A chemical inventory of the Truck Wash indicated that hydrogen fluoride, in an average 

daily amount of 1,000 to 9,999 pounds, was used at the site in 2010. Although the processes that 

occur at the truck wash are unknown, it is possible that PFAS are used in the buffing and waterproofing process. PFAS use has been linked to car wash facilities in various locations around the 

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AECOM 4-1

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, 2022b), 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 Martindale AASF (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, 2022b); 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 spring season, which was the earliest available 

time field resources were available to complete 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, 2022b).

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 

whether the collected data are of the right type, quality, and quantity to support the decisionmaking (DoD, 2019a; DoD, 2019b; USEPA, 2017).
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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, 2022b). 
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AECOM 5-1

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, Martindale Army Aviation Support Facility, San 

Antonio, Texas dated July 2020 (AECOM, 2020);

• Final Site Safety and Health Plan, Martindale Army Air Field, San Antonio, Texas dated 

March 2022 (AECOM, 2022a); and

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

Martindale Army Air Field, San Antonio, Texas dated April 2022 (AECOM, 2022b).

The SI field activities were conducted from 4 to 8 April 2022 and consisted of utility clearance, direct 

push boring, soil sample collection, temporary monitoring well installation, grab groundwater sample 

collection, and land surveying. Field activities were conducted in accordance with the SI QAPP 

Addendum (AECOM, 2022b), except as noted in Section 5.8.

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:

• Twenty-four (24) soil samples from six boring locations and eight hand auger locations;

• Five grab groundwater samples from five temporary wells; 

• Fourteen (14) 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, Nonconformance and Corrective Action Reports are provided in Appendix B4,

and investigation-derived waste (IDW) polygons are provided in Appendix B5. 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 
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AECOM 5-2

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

address the AOIs identified in the PA. 

A combined TPP Meeting 1 and 2 was held on 21 September 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, Texas ARNG, USACE, and Texas Commission on 

Environmental Quality. 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, 

2022b).

A TPP Meeting 3 was held on 26 July 2023, after the field event to discuss the results of the SI.

Meeting minutes for TPP 3 are 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 Texas 811 utility clearance provider to notify them of intrusive 

work on 28 March 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 4 April 2022 with input from the AECOM field team 

and Martindale AASF 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 spigot at Martindale AASF was sampled on 3 March 2022 to assess 

usability for decontamination of drilling equipment. Water from the spigot was transferred to a tote 

to allow for decontamination staging in an alternate area. Water from the tote was sampled on 7 

April 2022. Results of the samples collected from the spigot (MARTINDALEAAF-PW-01) and the 

tote (MDF-PW-01) confirmed this source and container to be acceptable for use in this 

investigation; therefore, they were used throughout the field activities. Specifically, the samples

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

decontamination water samples associated with the spigot source and tote 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, 2022b). 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

Soil samples were collected via direct push technology (DPT), in accordance with the SI QAPP 

Addendum (AECOM, 2022b). 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 5 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 in Table 5-1.
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At hand auger locations, one surface soil sample was collected from 0 to 2 feet bgs. At temporary 

well locations, 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 1-foot above the interpreted top of the groundwater table at the time of 

drilling, and one subsurface soil sample at the mid-point between the surface and the groundwater 

table. However, due to low recovery at AOI02-04, only two samples were collected, one surface 

soil sample (0 to 2 feet bgs) and one subsurface soil sample (9 to 12.5 feet bgs).

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 found lean clay as the dominant lithology of the 

unconsolidated sediments below the Martindale AASF. The borings were completed at depths 

between 20 and 33.5 feet bgs. Isolated layers of sand and silt were also observed in the borings 

with thicknesses ranging from a few inches to 5 feet. These observations are consistent with the 

understood depositional environment of the region.

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, 2022b).

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, 2022b) using bentonite chips at completion 

of sampling activities. Borings were installed in grass areas to avoid disturbing concrete or asphalt 

surfaces.

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 10-foot

section of 1-inch Schedule 40 poly-vinyl chloride (PVC) screen with sufficient casing to reach 

ground surface. The temporary well was set in an open hole without filter pack and 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 
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AECOM 5-4

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 

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, 2022b).

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.

Groundwater was slow to recharge at temporary wells AOI01-04 and MDF-02. As a result, the 

field duplicate sample and MS/MSD samples from AOI01-04 were not collected immediately 

following the collection of the primary sample, but approximately 4 to 20 hours later, following 

periods of recharge. Sample dates and times are presented on Table 5-1. Due to low 

groundwater volume, only one container was able to be collected from MDF-02. At the laboratory, 

the sample MDF-02-GW was not spiked with extraction internal standards (EIS) because there 

was only one container to extract. Analysis of this sample was cancelled, as the data would not 

usable due to insufficient volume. 

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

accordance with the SI QAPP Addendum (AECOM, 2022) by removing the PVC and backfilling 

the hole with bentonite chips.

5.4 Water Level Measurements

Groundwater gauging was performed between 6 April 2022 and 7 April 2022. Due to very slow 

recovery of water in some wells, stable water levels were not obtainable on a single day and a 

synoptic event was not possible. See Section 5.8 for an explanation of this deviation. Water level 

measurements were taken from the northern side of each 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 Texas-licensed land surveyors following 

guidelines provided in the SOPs provided in the SI QAPP Addendum (AECOM, 2022b). Survey 

data from the newly installed wells on the facility were collected on 7 April 2022 in the applicable 

Universal Transverse Mercator zone projection with North American Datum 1983 (NAD83 [2011])

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, 2022b) and with the DAGuidance for Addressing Releases of PFAS, Q18 (DA, 

2018).
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Soil IDW generated at hand augured locations were left in place at the point of source. 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.

Soil IDW (i.e., soil cuttings) generated during drilling activities were containerized in properly 

labeled, 55-gallon Department of Transportation (DOT)-approved steel drums and left onsite in a 

designated waste storage area. The soil IDW was not sampled and assumes the characteristics 

of the associated soil samples collected from that source location. ARNG will coordinate waste 

profiling, transportation, and disposal of the solid IDW. 

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

decontamination fluids) were contained in labeled, 55-gallon DOT-approved steel drums, and left 

onsite in a designated waste storage area. The liquid IDW was not sampled and assumes the 

characteristics of the associated groundwater samples collected from that source location. Based 

on laboratory results, containerized liquid IDW will be managed and disposed by ARNG under a 

separate contract for Treating Liquid Investigation-Derived Material (Purge water, drilling water, and 

decontamination fluids) (EA Engineering, Science, and Technology, Inc., 2021).

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

Five deviations from the SI QAPP Addendum were identified during review of the field 

documentation. The deviations are noted below and documented in Nonconformance and 

Corrective Action Reports (Appendix B4): 

• During the installation of temporary monitoring wells, a mid-point sample was not collected 

from boring AOI02-04 because the deepest interval sample required all the available soil 

volume to collect the parent sample, duplicate sample, and the MS/MSD. Additionally, upon 

review of field documentation, it was discovered that sample AOI02-04-SB-9-12.5 (including 

its field duplicate and matrix spike/matrix duplicate) was inadvertently shipped to the 

laboratory but not logged in during sample check-in and, therefore, not analyzed. Thus, only 

one soil sample was analyzed for AOI02-04, rather than three samples. As a result, the 

other soil and groundwater samples collected at AOI 2 were collectively used to determine 

whether further investigation of the AOI is needed in an RI. This action was documented in 

a nonconformance and corrective action report provided in Appendix B4.

• During groundwater sampling of temporary monitoring wells, groundwater was slow to 

recharge at MDF-02. As a result, there was only enough volume to fill one sample container. 

At the laboratory, the sample MDF-02-GW was not spiked with EIS since there was only 

one container to extract. Due to insufficient sample volume, analysis for this sample was 

cancelled, as the data would not be usable. This action was documented in a 

nonconformance and corrective action report provided in Appendix B4.
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 5-6

• Per the SI QAPP addendum, field duplicate soil samples are to be collected at a rate of 

10%. During soil sampling, field duplicates were collected at a rate of 10% (3 for 25 

samples). However, soil sample AOI02-04-SB-9-12.5, its field duplicate (AOI02-04-SB-9-

12.5-D), and matrix spike/matrix duplicate samples (AOI02-04-SB-9-12.5-MS, AOI02-04-

SB-9-12.5-MSD) were shipped to the laboratory but not logged in during sample check in 

due to confusion with the chain of custody. Therefore, these samples were not analyzed, 

resulting in a field duplicate rate of approximately 8% (2 for 24 samples). This action was 

documented in a nonconformance and corrective action report provided in Appendix B4.

• Per the SI QAPP addendum, a synoptic water level measurements were to be collected 

from the newly installed temporary monitoring wells. During the field event, all wells were 

intended to be gauged on the same day prior to well abandonment. However, wells AOI02-

04 and AOI03-02 were pumped dry and not recharging at a fast enough rate to give accurate 

water level measurements. As a result, a synoptic gauging event was not possible in order 

to achieve field schedule. Wells AOI02-04 and AOI03-02 were excluded from contouring 

since stable static water level measurements could not be obtained due to inadequate 

recharge. The groundwater levels measured prior to sampling at all other wells were used 

to generate the facility contour map (Figure 2-4). This action was documented in a 

nonconformance and corrective action report provided in Appendix B4. 

• Due to a laboratory error, the grain size samples collected at AOI01-04 and AOI03-02 could 

not be analyzed. This deviation was documented in a nonconformance and corrective action 

report provided in Appendix B4.
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Martindale AASF, Texas

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs) LC/MS/MS compliant with QSM 5.3 Table B-15 TOC (USEPA Method 9060A) pH (USEPA Method 9045D) Grain Size (ASTM D-422) Comments

AOI01-01-SB-00-02 4/4/2022 14:15 0 - 2 x

AOI01-02-SB-00-02 4/4/2022 14:55 0 - 2 x

AOI01-03-SB-00-02 4/4/2022 13:30 0 - 2 x

AOI01-04-SB-00-02 4/4/2022 15:10 0 - 2 x x x

AOI01-04-SB-13-15 4/4/2022 16:45 13 - 15 x x

AOI01-04-SB-31.5-33.5 4/4/2022 16:50 31.5 - 33.5 x

AOI02-01-SB-00-02 4/5/2022 10:20 0 - 2 x

AOI02-02-SB-00-02 4/5/2022 9:40 0 - 2 x x x

AOI02-03-SB-00-02 4/5/2022 8:30 0 - 2 x

AOI02-04-SB-00-02 4/5/2022 11:45 0 - 2 x

AOI02-04-SB-00-02-D 4/5/2022 11:45 0 - 2 x FD

AOI02-04-SB-00-02-MS 4/5/2022 11:45 0 - 2 x MS

AOI02-04-SB-00-02-MSD 4/5/2022 11:45 0 - 2 x MSD

AOI03-01-SB-00-02 4/5/2022 10:55 0 - 2 x

AOI03-02-SB-00-02 4/6/2022 15:50 0 - 2 x

AOI03-02-SB-06-08 4/6/2022 17:35 6 - 8 x

AOI03-02-SB-12.5-15 4/6/2022 17:20 12.5 - 15 x x

AOI03-02-SB-12.5-15-D 4/6/2022 17:20 12.5 - 15 x x x FD

AOI03-02-SB-12.5-15-MS 4/6/2022 17:20 12.5 - 15 x MS

AOI03-02-SB-12.5-15-MSD 4/6/2022 17:20 12.5 - 15 x MSD

AOI03-03-SB-00-02 4/5/2022 11:58 0 - 2 x x x

MDF-01-SB-00-02 4/5/2022 16:55 0 - 2 x

MDF-01-SB-08-10 4/6/2022 10:40 8 - 10 x

MDF-01-SB-14-15.5 4/6/2022 10:35 14 - 15.5 x

MDF-02-SB-00-02 4/5/2022 13:35 0 - 2 x

MDF-02-SB-04-06 4/5/2022 15:55 4 - 6 x

MDF-02-SB-08-10 4/5/2022 15:58 8 - 10 x

MDF-03-SB-00-02 4/5/2022 12:25 0 - 2 x

MDF-03-SB-05-07 4/5/2022 12:30 5 - 7 x

MDF-03-SB-10-12 4/5/2022 12:35 10 - 12 x

AOI01-04-GW 4/7/2022 12:25 NA x

AOI01-04-GW-D 4/7/2022 16:45 NA x FD

AOI01-04-GW-MS 4/8/2022 7:45 NA x MS

AOI01-04-GW-MSD 4/7/2022 16:45 NA x MSD

AOI02-04-GW 4/7/2022 11:45 NA x

AOI03-02-GW 4/7/2022 5:45 NA x

MDF-01-GW 4/7/2022 8:00 NA x

MDF-03-GW 4/6/2022 14:00 NA x

Soil Samples

Groundwater Samples

AECOM 5-7 
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Martindale AASF, Texas

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs) LC/MS/MS compliant with QSM 5.3 Table B-15 TOC (USEPA Method 9060A) pH (USEPA Method 9045D) Grain Size (ASTM D-422) Comments

MARTINDALEAAF-PW-01 3/3/2022 9:45 NA x

spigot used for 

decon source 

water

MDF-FRB-01 4/7/2022 7:35 NA x

MDF-ERB-01 4/7/2022 7:30 NA x pump

MDF-ERB-02 4/6/2022 15:45 NA x hand auger

MDF-PW-01 4/7/2022 10:46 NA x

tote with decon 

source water

Notes:

AASF = Army Aviation Support Facility

AOI = Area of Interest

ASTM = American Society for Testing and Materials

bgs = below ground surface

ERB = equipment rinsate blank

FD = field duplicate

FRB = field reagent blank

GW = groundwater

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MDF = Martindale Facility

MS/MSD = matrix spike/ matrix spike duplicate

PW = potable water

QSM = Quality Systems Manual

SB = soil boring

TOC = total organic carbon

USEPA = United States Environmental Protection Agency

Quality Control Samples

AECOM 5-8 
Table 5-2

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

Site Inspection Report, Martindale AASF, Texas

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)

Depth to 

Water

(feet bgs)

Groundwater 

Elevation

(feet NAVD88)

AOI01-04 33.5 23.5 - 33.51 671.04 670.70 16.1 15.76 654.94

MDF-03 27.5 17.5 - 27.51 667.14 666.95 10.54 10.35 656.60

AOI02-04 22 12 - 22 675.30 674.62 17.49 16.81 657.81

MDF-02 20 10 - 20 675.55 675.56 12.89 12.90 662.66

AOI03-02 30 20 - 30 675.04 674.68 25.98 25.62 649.06

MDF-01 31.9 21.9 - 31.91 674.36 673.96 9.52 9.12 664.84

Notes:

1

 Temporary well screen set above total depth to capture groundwater interface

AASF = Army Aviation Support Facility

AOI = Area of Interest

bgs = below ground surface

btoc = below top of casing

MDF = Martindale Facility

NA = not applicable

NAVD88 = North American Vertical Datum 1988

1

2

3

AECOM 5-9 
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 5-10

THIS PAGE INTENTIONALLY BLANK
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"S

"S

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"S

"S

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AOI01-02

AOI01-04

AOI02-03

AOI03-02

MDF-01 MDF-02

AOI02-02

AOI02-01

AOI02-04

AOI03-03

AOI01-03

AOI03-01

AOI01-01

MDF-03

Rosillo

Cree

AOI 1 k

AOI 3

AOI 2

0 205 410 820

Feet

Legend

?! DPT Temporary Well

"S Surface Soil Sample

Area of Interest

Facility Boundary

Water Body

River/Stream

Surface Water Flow Direction

Groundwater Flow Direction ­ Figure 5-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

3/20/2023

3/20/2023

3/20/2023

MS

MB

CM

GIS BY

CHK BY

PM

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

3/20/2023

1:4,922

Site Inspection Sample Locations

12420 Milestone Center Drive

Germantown, MD 20876

AECOM 5-11
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 5-12

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Martindale AASF, San Antonio, Texas

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 6-5 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 to 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

Martindale AASF, San Antonio, Texas

AECOM 6-2

6.2 Soil Physicochemical Analyses

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

size, 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 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: Grass Fire Near Flight Line. The soil and groundwater results are summarized on Table 

6-2 through Table 6-5. Soil and groundwater results are presented on Figure 6-1 through Figure 

6-7.

6.3.1 AOI 1 Soil Analytical Results

Surface soil was sampled from 0 to 2 feet bgs at boring locations AOI01-01 through AOI01-04, 

and MDF-03. Subsurface soil was also sampled from MDF-03 at depths of 5 to 7 feet bgs and 10 

to 12 feet bgs, and from AOI01-04 at depths of 13 to 15 feet bgs and 31.5 to 33.5 feet bgs. Figure 

6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 through Table 6-4

summarize the soil results, which are highlighted below.

• PFOS was detected below the SL in surface soil at locations AOI01-03 and MDF-03, 

with a maximum concentration of 0.353 J micrograms per kilogram (μg/kg). PFOA, 

PFHxS, PFNA, and PFBS were not detected in surface soil. 

• PFOS and PFHxS were detected below their SLs in shallow subsurface soil at location 

MDF-03, with concentrations of 0.628 J μg/kg and 0.045 J μg/kg, respectively. PFOA, 

PFNA, and PFBS were not detected in shallow subsurface soil.

• PFOA, PFOS, PFHxS, PFNA, and PFBS were not detected in deep subsurface soil.

6.3.2 AOI 1 Groundwater Analytical Results

Figure 6-6 and Figure 6-7 present the ranges of detections in groundwater. Table 6-5

summarizes the groundwater results.

Groundwater was sampled from temporary monitoring wells AOI01-04 and MDF-03. PFOA was 

detected above the SL of 6 nanograms per liter (ng/L) in one well, with a maximum concentration 

of 12.2 J ng/L in the field duplicate sample AOI01-04-GW-D. PFOS was detected in temporary 

monitoring well MDF-03 above the SL of 4 ng/L, with a concentration of 25.9 ng/L. PFHxS, and 

PFBS were detected below their SLs, with maximum concentrations of 5.83 ng/L and 3.07 J+ 

ng/L, respectively. PFNA was not detected in groundwater at AOI 1. 
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 6-3

6.3.3 AOI 1 Conclusions

Based on the results of the SI, PFOS was detected below the SL in surface soil; PFOS and PFHxS 

were detected below their SLs in subsurface soil. PFOA and PFOS were detected in groundwater,

at concentrations above their SLs, PFHxS and PFBS were detected below their SLs in 

groundwater, and PFNA was not detected in groundwater. 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: Area East of the Maintenance Hangar. The results in soil and groundwater are summarized 

on Table 6-2 through Table 6-5. Soil and groundwater results are presented on Figure 6-1

through Figure 6-7.

6.4.1 AOI 2 Soil Analytical Results

Surface soil was sampled from 0 to 2 feet bgs at boring locations AOI02-01 through AOI02-04, 

and MDF-02. Subsurface soil was also sampled from boring location MDF-02 at depths of 4 to 6 

feet bgs and 8 to 10 feet bgs. Figure 6-1 through Figure 6-5 present the ranges of detections in 

soil. Table 6-2 and Table 6-3 summarize the soil results.

PFOA, PFOS, PFHxS, and PFNA were detected below their SLs, with the following maximum 

concentrations: PFOA at 0.184 J μg/kg, PFOS at 2.61 μg/kg, PFHxS at 0.538 J μg/kg, and PFNA 

at 0.155 J μg/kg. PFBS was not detected in surface soil. PFOA, PFOS, PFHxS, PFNA, and PFBS 

were not detected in shallow subsurface soil. 

6.4.2 AOI 2 Groundwater Analytical Results

Figure 6-6 and Figure 6-7 present the ranges of detections in groundwater. Table 6-5

summarizes the groundwater results.

Groundwater was sampled from temporary monitoring well AOI02-04. PFOS was detected above 

the SL of 4 ng/L, with a concentration of 35.3 ng/L. PFOA, PFHxS, and PFBS were detected 

below their SLs, with concentrations of 2.22 J ng/L, 21.3 ng/L, and 6.59 ng/L, respectively. PFNA 

was not detected in groundwater at AOI02-04. 

6.4.3 AOI 2 Conclusions

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

concentrations below their SLs. PFBS was not detected in surface soil. PFOA, PFOS, PFHxS, 

PFNA, and PFBS were not detected in shallow subsurface soil. PFOS was detected in 

groundwater, at a concentration above the SL. PFOA, PFHxS, and PFBS were detected below 

their SLs in groundwater. PFNA was not detected in groundwater. Based on the exceedance of 

the SL 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: Wash Rack. The results in soil and groundwater are presented in Table 6-2 through Table 

6-5. Soil and groundwater results are presented on Figure 6-1 through Figure 6-7.
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 6-4

6.5.1 AOI 3 Soil Analytical Results

Surface soil was sampled from 0 to 2 feet bgs at boring locations AOI03-01 through AOI03-03, 

and MDF-01. Subsurface soil was also sampled from AOI03-02 at depths of 6 to 8 feet bgs and 

12.5 to 15 feet bgs, and from MDF-01 at depths of 8 to 10 feet bgs and 14 to 15.5 feet bgs. Figure 

6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 and Table 6-3

summarize the soil results, which are highlighted below.

• PFOA, PFOS, PFHxS, PFNA, and PFBS were detected below their SLs in at least two

surface soil locations, with the following maximum concentrations: PFOA at 0.375 J 

μg/kg, PFOS at 5.18 μg/kg, PFHxS at 4.77 μg/kg, PFNA at 0.127 J μg/kg, and PFBS at 

0.044 J μg/kg.

• PFOS, PFHxS, and PFBS were detected below their SLs in shallow subsurface soil, 

with the following maximum concentrations: PFOS at 0.070 J μg/kg, PFHxS at 0.760 J 

μg/kg, and PFBS at 0.167 J μg/kg.

• PFOA and PFNA were not detected in shallow subsurface soil. 

6.5.2 AOI 3 Groundwater Analytical Results

Figure 6-6 and Figure 6-7 present the ranges of detections in groundwater. Table 6-5

summarizes the groundwater results.

Groundwater was sampled from temporary monitoring wells AOI03-02 and MDF-01. PFOS was 

detected above the SL of 4 ng/L at AOI03-02, with a concentration of 23.4 ng/L. PFOA, PFHxS, 

PFNA, and PFBS were detected below their SLs, with the following maximum concentrations: 

PFOA at 2.95 J ng/L, PFHxS at 28.9 ng/L, PFNA at 1.42 J ng/L, and PFBS at 7.05 ng/L. 

6.5.3 AOI 3 Conclusions

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

soil, at concentrations below their SLs. PFOS, PFHxS, and PFBS were detected in subsurface 

soil at concentrations below their SLs. PFOA and PFNA were not detected in subsurface soil. 

PFOS was detected in groundwater, at a concentration above the SL. PFOA, PFHxS, PFNA, and 

PFBS were detected below their SLs in groundwater. Based on the exceedance of the SL 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, Martinsdale AASF

Analyte OSD Screening 

Level a

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

PFBS 1900 ND U ND U ND U ND U ND U ND U ND U ND U ND U ND U

PFHxS 130 ND U ND U ND U ND U ND U ND U 0.538 J ND U 0.143 J 0.065 J

PFNA 19 ND U ND U ND U ND U ND U 0.026 J 0.136 J 0.155 J 0.061 J 0.070 J

PFOA 19 ND U ND U ND U ND U ND U ND U 0.184 J 0.104 J 0.176 J 0.138 J

PFOS 13 ND U ND U 0.064 J ND U 0.353 J 0.122 J 2.61 0.279 J 0.522 J 0.274 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS perfluorobutanesulfonic acid

References PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Interpreted Qualifiers Acronyms and Abbreviations

J = Estimated concentration AASF Army Aviation Support Facility

U = The analyte was not detected at a level greater than or equal to the adjusted DL AOI Area of Interest

D duplicate

Notes DL detection limit

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. ft feet

HQ hazard quotient

ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

ND analyte not detected above the LOD

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

AOI02

MDF-03-SB-00-02

04/05/2022

0-2 ft

AOI01

AOI01-02-SB-00-02

04/04/2022

0-2 ft

AOI01-03-SB-00-02

04/04/2022

0-2 ft 0-2 ft

AOI02-03-SB-00-02

04/05/2022

0-2 ft

AOI01-04-SB-00-02

Area of Interest

Sample ID

Sample Date

Depth

AOI01-01-SB-00-02

04/04/2022

0-2 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 residential scenario for incidental ingestion of contaminated soil.

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

AOI02-04-SB-00-02

04/05/2022

0-2 ft

AOI02-04-SB-00-02-D

04/05/2022

0-2 ft

AOI02-02-SB-00-02

04/04/2022 04/05/2022

0-2 ft

AOI02-01-SB-00-02

04/05/2022

0-2 ft

AECOM 6-5 
Table 6-2

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

Site Inspection Report, Martinsdale AASF

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual

PFBS 1900 ND U 0.029 J 0.044 J 0.022 J ND U

PFHxS 130 ND U 0.290 J 4.77 0.136 J ND U

PFNA 19 0.033 J 0.126 J ND U 0.127 J ND U

PFOA 19 ND U 0.166 J 0.375 J 0.285 J ND U

PFOS 13 0.087 J 4.30 4.09 5.18 0.219 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS perfluorobutanesulfonic acid

References PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Interpreted Qualifiers Acronyms and Abbreviations

J = Estimated concentration AASF Army Aviation Support Facility

U = The analyte was not detected at a level greater than or equal to the adjusted DL AOI Area of Interest

D duplicate

Notes DL detection limit

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. ft feet

HQ hazard quotient

ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

ND analyte not detected above the LOD

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

Area of Interest

Sample ID

Sample Date

Depth

AOI03-02-SB-00-02

04/06/2022

0-2 ft

AOI03 AOI03

AOI03-01-SB-00-02

04/05/2022

0-2 ft

MDF-02-SB-00-02

04/05/2022

0-2 ft

AOI02

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.

AOI03-03-SB-00-02

04/05/2022

0-2 ft

MDF-01-SB-00-02

04/05/2022

0-2 ft

AECOM 6-6
Table 6-3

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

Site Inspection Report, Martinsdale AASF

Analyte OSD Screening 

Level a

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

PFBS 25000 ND U ND U ND U ND U ND U 0.167 J 0.059 J 0.114 J ND U ND U

PFHxS 1600 ND U 0.045 J ND U ND U ND U 0.760 J 0.039 J 0.037 J ND U ND U

PFNA 250 ND U ND U ND U ND U ND U ND U ND U ND U ND U ND U

PFOA 250 ND U ND U ND U ND U ND U ND U ND U ND U ND U ND U

PFOS 160 ND U 0.628 J ND U ND U ND U 0.070 J ND U ND U ND U ND U

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS perfluorobutanesulfonic acid

References PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Interpreted Qualifiers Acronyms and Abbreviations

J = Estimated concentration AASF Army Aviation Support Facility

U = The analyte was not detected at a level greater than or equal to the adjusted DL AOI Area of Interest

D duplicate

Notes DL detection limit

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. ft feet

HQ hazard quotient

ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

MDF Martinsdale Army Air Field

ND analyte not detected above the LOD

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

12.5-15 ft

MDF-01-SB-08-10

04/06/2022

8-10 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)

MDF-01-SB-14-15.5

04/06/2022

4-6 ft 8-10 ft 6-8 ft 12.5-15 ft 14-15.5 ft

Area of Interest

Sample ID

Sample Date

Depth

AOI01-04-SB-13-15

04/04/2022

13-15 ft

AOI01

MDF-03-SB-05-07 MDF-03-SB-10-12

04/05/2022 04/05/2022

5-7 ft 10-12 ft

AOI02 AOI03

MDF-02-SB-04-06 MDF-02-SB-08-10

04/05/2022 04/05/2022

AOI03-02-SB-06-08

04/06/2022

AOI03-02-SB-12.5-15

04/06/2022

AOI03-02-SB-12.5-15-D

04/06/2022

AECOM 6-7
Table 6-4

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

Site Inspection Report, Martinsdale AASF

Area of Interest

Sample ID

Sample Date

Depth

Analyte Result Qual

PFBS ND U

PFHxS ND U

PFNA ND U

PFOA ND U

PFOS ND U

Interpreted Qualifiers Chemical Abbreviations

U = The analyte was not detected at a level greater than or equal to the adjusted DL PFBS perfluorobutanesulfonic acid

PFHxS perfluorohexanesulfonic acid

Notes PFNA perfluorononanoic acid

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Acronyms and Abbreviations

AASF Army Aviation Support Facility

AOI Area of Interest

DL detection limit

ft feet

ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

ND analyte not detected above the LOD

QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

μg/kg micrograms per kilogram

AOI01

AOI01-04-SB-31.5-33.5

04/04/2022

31.5-33.5 ft

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

AECOM 6-8
Table 6-5

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

Site Inspection Report, Martinsdale AASF

Analyte OSD Screening 

Level a

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

PFBS 601 2.19 J 3.07 J+ 2.08 J 6.59 7.05 2.36 J

PFHxS 39 3.37 J 4.56 J 5.83 21.3 28.9 2.04 J

PFNA 6 ND U ND UJ ND U ND U 1.42 J ND U

PFOA 6 10.4 12.2 J ND U 2.22 J 2.95 J 1.59 J

PFOS 4 2.50 J 3.11 J+ 25.9 35.3 23.4 3.72 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS perfluorobutanesulfonic acid

References PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Interpreted Qualifiers Acronyms and Abbreviations

J = Estimated concentration AASF Army Aviation Support Facility

J+ = Estimated concentration, biased high AOI Area of Interest

U = The analyte was not detected at a level greater than or equal to the adjusted DL D duplicate

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. DL detection limit

GW groundwater

Notes HQ hazard quotient

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

MDF Martinsdale Army Air Field

ND analyte not detected above the LOD

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual interpreted qualifier

USEPA United States Environmental Protection Agency

ng/l nanogram per liter

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.

AOI03-02-GW

04/07/2022

MDF-01-GW

04/07/2022

AOI01-04-GW-D

04/07/2022

AOI02-04-GW

04/07/2022

Sample ID

Sample Date

AOI01-04-GW

04/07/2022

MDF-03-GW

04/06/2022

AOI01 AOI03

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

Area of Interest AOI02

AECOM 6-9
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 6-10

THIS PAGE INTENTIONALLY BLANK
AOI01-02

AOI01-04

AOI02-03

AOI03-02

MDF-01 MDF-02

AOI02-02

AOI02-01

AOI02-04

AOI03-03

AOI01-03

AOI03-01

AOI01-01

MDF-03

Facility Boundary

Water Body

River/Stream ­ Figure 6-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

1/20/2023

1/20/2023

1/20/2023

MS

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CM

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CHK BY

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1:7,800

PFOA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

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

0 325 650 1,300

Feet

AECOM 6-11
AOI01-02

AOI01-04

AOI02-03

AOI03-02

MDF-01 MDF-02

AOI02-02

AOI02-01

AOI02-04

AOI03-03

AOI01-03

AOI03-01

AOI01-01

MDF-03

Facility Boundary

Water Body

River/Stream ­ Figure 6-2

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

1/20/2023

1/20/2023

1/20/2023

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PFOS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

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.

0 325 650 1,300

Feet

PFOS Results (μg/Kg)

ND

>ND - 13

>13 - 160

>160 - 1,600

>1,600

AECOM 6-12
AOI01-02

AOI01-04

AOI02-03

AOI03-02

MDF-01 MDF-02

AOI02-02

AOI02-01

AOI02-04

AOI03-03

AOI01-03

AOI03-01

AOI01-01

MDF-03

Facility Boundary

Water Body

River/Stream ­ Figure 6-3

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

1/20/2023

1/20/2023

1/20/2023

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PFBS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

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.

0 325 650 1,300

Feet

PFBS Results (μg/Kg)

ND

>ND - 10

>10 - 1,900

>1,900 - 25,000

>25,000

AECOM 6-13
AOI01-02

AOI01-04

AOI02-03

AOI03-02

MDF-01 MDF-02

AOI02-02

AOI02-01

AOI02-04

AOI03-03

AOI01-03

AOI03-01

AOI01-01

MDF-03

Facility Boundary

Water Body

River/Stream ­ Figure 6-4

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

1/20/2023

1/20/2023

1/20/2023

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PFHxS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

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.

0 325 650 1,300

Feet

PFHxS Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

AECOM 6-14
AOI01-02

AOI01-04

AOI02-03

AOI03-02

MDF-01 MDF-02

AOI02-02

AOI02-01

AOI02-04

AOI03-03

AOI01-03

AOI03-01

AOI01-01

MDF-03

Facility Boundary

Water Body

River/Stream ­ Figure 6-5

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

1/20/2023

1/20/2023

1/20/2023

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PFNA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

AOI01-04

AOI03-02

MDF-01 MDF-02

MDF-03

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.

0 325 650 1,300

Feet

PFNA Results (μg/Kg)

ND

>ND - 19

>19 - 250

>250 - 2,500

>2,500

AECOM 6-15
AOI01-04

AOI03-02

MDF-01

AOI02-04

MDF-03

Facility Boundary

Water Body

River/Stream

Groundwater Flow Direction ­ Figure 6-6

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

3/20/2023

3/20/2023

3/20/2023

MS

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CM

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PFOA, PFOS, and PFBS Detections in Groundwater

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01

AOI02-04

MDF-03

AOI01-04

AOI03-02

MDF-01

AOI02-04

MDF-03

PFOA PFOS PFBS

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

0 325 650 1,300

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 6-16
AOI01-04

AOI03-02

MDF-01

AOI02-04

MDF-03

Facility Boundary

Water Body

River/Stream

Groundwater Flow Direction ­ Figure 6-7

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Martindale AASF, TX

3/20/2023

3/20/2023

3/20/2023

MS

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CM

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PFHxS and PFNA Detections in Groundwater

12420 Milestone Center Drive

Germantown, MD 20876

AOI01-04

AOI03-02

MDF-01

AOI02-04

MDF-03

PFHxS PFNA

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

0 225 450 900

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 6-17
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 6-18

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 7-1

7. Exposure Pathways

The CSMs for each AOI, revised based on the SI findings, are presented on Figure 7-1 and

Figure 7-2. 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 and the other four elements are satisfied, 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 the area where AFFF was used to put out a grass fire near the southwest end of the flight 

line. PFOS was detected two orders of magnitude below the SL in surface soil at AOI 1, with a 

maximum concentration of 0.353 J ug/kg. Site workers and construction workers could contact 

constituents in surface soil via incidental ingestion and inhalation of dust. Therefore, the surface 

soil exposure pathway for site workers and future construction workers are potentially complete. 
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 7-2

Residential properties exist adjacent to the facility, along the western and southwestern 

boundaries. However, AOI 1 is over 0.2 miles from the nearest residential property. Therefore, the 

surface soil exposure pathway for residents via incidental inhalation of dust is considered 

incomplete. The relevant compounds were detected below their SLs in shallow subsurface soil at 

AOI 1. Construction workers could contact constituents in subsurface soil via incidental ingestion;

therefore, the subsurface soil exposure pathway for future construction workers is potentially 

complete. There are no recreational areas immediately adjacent to the facility. Additionally, the 

facility is secured against trespassers; therefore, the soil exposure pathways are incomplete to 

recreational users/trespassers. The CSM for AOI 1 is presented on Figure 7-1. 

7.1.2 AOI 2

AOI 2 is the area east of the Maintenance Hangar where AFFF fluids stored in Tri-MaxTM units 

were disposed of during maintenance events. A firetruck that likely contained AFFF was also 

stored in this area. 

The relevant compounds were detected in surface soil at AOI 2. Site workers and construction 

workers could contact constituents in surface soil via incidental ingestion and inhalation of dust. 

Therefore, the surface soil exposure pathway for site workers and future construction workers are 

potentially complete. Residential properties exist adjacent to the facility, along the western and 

southwestern boundaries. However, AOI 2 over 0.2 miles the nearest residential property. 

Therefore, the surface soil exposure pathway for residents via incidental inhalation of dust is 

considered incomplete. The relevant compounds were not detected in subsurface soil at AOI 2; 

therefore, all exposure pathways are considered incomplete. There are no recreational areas 

immediately adjacent to the facility. Additionally, the facility is secured against trespassers; 

therefore, the soil exposure pathways are incomplete to recreational users/trespassers. The CSM

for AOI 2 is presented on Figure 7-2. 

7.1.3 AOI 3

AOI 3 is the wash rack where AFFF fluids stored in Tri-MaxTM units would have been disposed of

during maintenance events when old AFFF was replaced with new AFFF in the units. 

The relevant compounds were detected in surface soil and subsurface soil at AOI 3. Site workers 

and construction workers could contact constituents in surface soil via incidental ingestion and 

inhalation of dust. Therefore, the surface soil exposure pathway for site workers and future 

construction workers are potentially complete. Residential properties exist adjacent to the facility, 

along the western and southwestern boundaries. However, AOI 3 is at least 0.2 mile from the 

nearest residential property. Therefore, the surface soil exposure pathway for residents via 

incidental inhalation of dust is considered incomplete. The relevant compounds were detected 

below their SLs in shallow subsurface soil at AOI 3. Therefore, construction workers could contact 

constituents in subsurface soil via incidental ingestion and the subsurface soil exposure pathway 

for future construction workers is potentially complete. There are no recreational areas 

immediately adjacent to the facility. Additionally, the facility is secured against trespassers; 

therefore, the soil exposure pathways are incomplete to recreational users/trespassers. The CSM

for AOI 3 is presented on Figure 7-1.

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.
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 7-3

7.2.1 AOI 1, AOI 2, and AOI 3

PFOA and/or PFOS were detected above their SLs in groundwater at AOI 1, AOI 2, and AOI 3. 

Depth to water measured in April 2022 during the SI ranged from 9.12 to 25.62 feet bgs. 

Therefore, construction workers could reasonably come in contact with shallow groundwater

during construction activities, and the exposure pathway via incidental ingestion for future 

construction workers is considered potentially complete. There are no downgradient drinking 

water wells within 3 miles of the facility. The nearest water supply well is located upgradient, 

approximately 1.5 miles north of the facility and is over 1,000 feet deep. Additionally, the shallow 

aquifer is not used as drinking water in the San Antonio area and is a discontinuous perched lens 

with little or no interconnection with the Edwards aquifer. Therefore, the pathway for exposure to 

off-facility residents via ingestion of groundwater is considered incomplete. Drinking water at the 

facility is provided by the City of San Antonio; therefore, the pathway for exposure to site workers 

via ingestion of groundwater is also considered incomplete. The CSMs are presented on Figure 

7-1 and Figure 7-2. 

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.

7.3.1 AOI 1, AOI 2, AOI 3

PFAS are water soluble and can migrate readily from soil to surface water via leaching and runoff. Because the relevant compounds were detected in soil at the AOIs, it is possible that those 

compounds may have migrated from soil to surface water in drainage ditches and the retention 

pond. Therefore, the surface water and sediment ingestion exposure pathway for site workers

and future construction workers is considered potentially complete. It is likely that surface water 

flows from the retention pond to Rosillo Creek, which discharges to Salado Creek, under heavy 

rain conditions. Additionally, depending on the position of the diverter valve at the OWS,

wastewater that collects in the wash rack could discharge to Rosillo Creek. Due to potential 

recreation use of Rosillo Creek and Salado Creek, the surface water and sediment ingestion 

exposure pathway for recreational users is also considered potentially complete. The CSM for 

AOIs 1 and 3 is presented on Figure 7-1 and Figure 7-2.
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 7-4

THIS PAGE INTENTIONALLY BLANK
Media

SOURCE PATHWAY RECEPTOR

AOI 1

AOI 3

Firefighting, 

Tri-MaxTM 

Maintenance

Surface soil

Human 

activities

Precipitation/ 

run-off

Leaching/ 

infiltration

Airborne soil 

particulate

Surface soil 

at AOI

Surface 

water/ 

sediment

Subsurface 

soil

Shallow 

groundwater4

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

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Potentially Complete Pathway 

with Exceedance of SL

/ / / /

Site Worker Construction Worker3 Resident1,2 Trespasser/ Recreational User1

Site Worker Construction Worker3 Resident1,2

/ / / /

/ / / /

/ / / /

/ / / /

LEGEND

Figure 7-1

Conceptual Site Model, AOI 1 and AOI 3

Martindale AASF

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

Trespasser/ Recreational User1

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.

4. The shallow aquifer is not used for drinking

water. However, construction workers could be

exposed via incidental ingestion during construction

activities.

Notes:

AECOM 7-5 
Media

SOURCE PATHWAY RECEPTOR

AOI 2 Tri-MaxTM 

Maintenance Surface soil

Human 

activities

Precipitation/ 

run-off

Leaching/ 

infiltration

Airborne soil 

particulate

Surface soil 

at AOI

Surface 

water/ 

sediment

Subsurface 

soil

Shallow 

groundwater4

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

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Potentially Complete Pathway 

with Exceedance of SL

/ / / /

Site Worker Construction Worker3 Resident1,2 Trespasser/ Recreational User1

Site Worker Construction Worker3 Resident1,2

/ / / /

/ / / /

/ / / /

/ / / /

LEGEND

Figure 7-2

Conceptual Site Model, AOI 2

Martindale AASF

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

Trespasser/ Recreational User1

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.

4. The shallow aquifer is not used for drinking

water. However, construction workers could be

exposed via incidental ingestion during construction

activities.

Notes:

AECOM 7-6
Site Inspection Report

Martindale AASF, San Antonio, Texas

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 4 to 8 April 2022 and consisted of utility clearance, direct 

push boring, soil sample collection, temporary monitoring well installation, grab groundwater sample 

collection, and land surveying. Field activities were conducted in accordance with the SI QAPP 

Addendum (AECOM, 2022b), except as previously noted in Section 5.8. 

To fulfill the project DQOs set forth in the approved SI QAPP Addendum (AECOM, 2022b), 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. 

• Twenty-four (24) soil samples from six boring locations and eight hand auger locations; 

• Five grab groundwater samples from five temporary wells; 

• Fourteen (14) 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 CSMs were 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 under CERCLA is warranted in an RI for each 

of the three AOIs (see Table 8-1). Based on the CSMs developed and revised in light of the SI 

findings, exposure to drinking water receptors from the AOIs from sources on the facility resulting 

from historical DoD activities is considered incomplete. Sample analytical concentrations 

collected during the SI were compared to 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 the relevant compounds in soil at AOI 1 were below 

their SLs. 

• PFOA in groundwater exceeded the SL of 6 ng/L, with a maximum concentration of 

12.2 J ng/L in the field duplicate sample AOI01-04-GW-D. PFOS in groundwater 

exceeded the SL of 4 ng/L, with a concentration of 25.9 ng/L at MDF-03. The detected 

concentrations of the other relevant compounds in groundwater were below their

SLs. 

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

warranted in an RI. 
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Martindale AASF, San Antonio, Texas

AECOM 8-2

• At AOI 2:

• The detected concentrations of the relevant compounds in soil at AOI 2 were below 

their SLs. 

• PFOS in groundwater exceeded the SL of 4 ng/L, with a concentration of 35.3 ng/L 

at location AOI02-04. The detected concentrations of the other relevant compounds

in groundwater were below their SLs. 

• Based on the exceedance of the SL in groundwater, further evaluation at AOI 2 is 

warranted in an RI. 

• At AOI 3:

• The detected concentrations of the relevant compounds in soil at AOI 3 were below 

their SLs. 

• PFOS in groundwater exceeded the SL of 4 ng/L, with a concentration of 23.4 ng/L 

at location AOI03-02. The detected concentrations of the other relevant compounds

in groundwater were below their SLs. 

• Based on the exceedance of the SL in groundwater, further evaluation at AOI 3 is 

warranted in an RI. 

The purpose of facility boundary well MDF-02 was to determine if potential offsite migration is 

occurring. However, due to a laboratory error, MDF-02 groundwater results could not be obtained. 

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. 
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 8-3

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 

Grass Fire 

Near Flight 

Line

Proceed to RI 

2 

Area East of 

the 

Maintenance 

Hangar

N/A Proceed to RI

3 Wash Rack 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 8-4

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AECOM 9-1

9. References

AECOM. 2018a. Final Site Inspection Programmatic Uniform Federal Policy-Quality Assurance 

Project Plan, Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA) 

Impacted Sites ARNG Installations, Nationwide Contract No. W912DR-12-D-0014/

W912DR17F0192. 9 March.

AECOM. 2018b. Final Programmatic Accident Prevention Plan, Perfluorooctane Sulfonic Acid 

(PFOS) and Perfluorooctanoic Acid (PFOA) Impacted Sites ARNG Installations, Nationwide 

Contract No. W912DR-12-D-0014/W912DR17F0192. July.

AECOM. 2020. Final Preliminary Assessment Report, Martindale Army Aviation Support Facility, 

San Antonio, Texas. July. 

AECOM. 2022a. Final Site Safety and Health Plan, Martindale Army Air Field, San Antonio, Texas, 

Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA) Impacted Sites 

ARNG Installations, Nationwide. March. 

AECOM. 2022b. Final Site Inspection Uniform Federal Policy-Quality Assurance Project Plan 

Addendum, Martindale Army Air Field, San Antonio, Texas, Perfluorooctane Sulfonic Acid 

(PFOS) and Perfluorooctanoic Acid (PFOA) Impacted Sites ARNG Installations, Nationwide. 

April. 

Assistant Secretary of Defense. 2022. Investigation Per- and Polyfluoroalkyl Substances within 

the Department of Defense Cleanup Program. United States Department of Defense. 

6 July. 

Bureau of Economic Geology, University of Texas at Austin, 1982. Geologic Atlas of Texas, San 

Antonio Sheet, https://www.twdb.texas.gov/groundwater/aquifer/GAT/san-antonio.htm, 

Accessed 14 January 2020.

DA. 2018. Army Guidance for Addressing Releases of Per- and Polyfluoroalkyl Substances. 

4 September.

DoD. 2019a. Department of Defense (DoD), Department of Energy (DOE) Consolidated Quality 

Systems Manual (QSM) for Environmental Laboratories, Version 5.3. 

DoD. 2019b. General Data Validation Guidelines. Environmental Data Quality Workgroup. 

4 November.

EA Engineering, Science, and Technology, Inc. 2021. Standard Operating Procedure No. 042A

for Treating Liquid Investigation-Derived Material (Purge water, drilling water, and

decontamination fluids). Revision 1. March.

Guelfo, J.L. and Higgins, C.P. 2013. Subsurface Transport Potential of Perfluoroalkyl Acids at 

Aqueous Film-Forming Foam (AFFF)-Impacted Sites. Environmental Science and Technology 

47(9): 4164-71.

Higgins, C.P., and Luthy, R.G. 2006. Sorption of perfluorinated surfactants on 

sediments. Environmental Science and Technology 40 (23): 7251-7256.

ITRC. November 2017. History and Use of Per- and Polyfluoroalkyl Substances (PFAS).

https://pfas-1.itrcweb.org/wpcontent/uploads/2017/11/pfas_fact_sheet_history_and_use__11_13_17.pdf. Accessed 12 

December 2019.

ITRC. 2018. Environmental Fate and Transport for Per- and Polyfluoroalkyl Substances. March. 
Site Inspection Report

Martindale AASF, San Antonio, Texas

AECOM 9-2

National Weather Service. 2022. Monthly Climate Normals (1991-2020) - San Antonio Area, TX. 

https://www.weather.gov/wrh/Climate?wfo=ewx. Accessed 1 November 2022. 

Texas Board of Water Engineers (TBWE). August 1954. Ground-water Resources of the San 

Antonio Area, Texas, A Progress Report of Current Studies, by Joe W. Lang, Geologist, 

United States Geological Survey. 

http://www.twdb.texas.gov/publications/reports/bulletins/doc/B5412.pdf. Accessed 11 

September 2019. 

TBWE, 1959. Bulletin 5911: Ground-Water Geology of Bexar County, Texas. 

http://www.twdb.texas.gov/publications/reports/bulletins/doc/B5911/B5911.pdf. Accessed 14 

January 2020.

USACE. 2016. Technical Project Planning Process, EM-200-1-2. 26 February.

US Army Center for Health Promotion and Preventive Medicine (USACHPPM). January 1997. 

Site Assessment Survey No. 38-EH-5684-97. Texas Army National Guard. Martindale Army 

Aviation Support Facility. San Antonio, Texas.

USEPA. 1980. Comprehensive Environmental Response, Compensation, and Liability Act 

(CERCLA). 

USEPA. 1994. National Oil and Hazardous Substances Pollution Contingency Plan (Final Rule). 

40 CFR Part 300; 59 Federal Register 47384. September.

USEPA. 2001. Risk Assessment Guidance for Superfund, Volume I: Human Health Evaluation 

Manual (Part D, Standardized Planning, Reporting, and Review of Superfund Risk 

Assessments). December.

USEPA. 2017. National Functional Guidelines for Organic Superfund Data Review. OLEM 

9355.0-136, EPA-540-R-2017-002. Office of Superfund Remediation and Technology 

Innovation. January.

USFWS. 2022. Species by County Report, County: Bexar, Texas. Environmental Conservation 

Online System. Accessed 19 October 2022 at https://ecos.fws.gov/ecp/report/specieslistings-by-current-range-county?fips=48029. 

Weather Atlas. 2022. San Antonio, TX – Detailed climate information and monthly weather 

forecast. The climate of San Antonio. https://www.weather-us.com/en/texas-usa/san-antonioclimate. Accessed 1 November 2022. 

Xiao, F., Simcik, M. F., Halbach, T. R., and Gulliver, J. S. 2015, Perfluorooctane sulfonate (PFOS) 

and perfluorooctanoate (PFOA) in soils and groundwater of a U.S. metropolitan area: 

Migration and implications for human exposure. Water Research 72: 64-74.