FINAL

Site Inspection Report 

Aviation Classification Repair 

Activity Depot 

Gulfport, Mississippi 

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 

August 2023

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
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Table of Contents

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

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

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

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

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

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

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

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

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

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

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

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

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

2.3 History of PFAS Use ...............................................................................................2-3

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

3.1 AOI 1 Release Area A.............................................................................................3-1

3.2 AOI 2 Release Area B.............................................................................................3-1

3.3 AOI 3 Release Area C ............................................................................................3-1

3.4 AOI 4 Release Areas D & E....................................................................................3-2

3.5 Adjacent Sources....................................................................................................3-2

3.5.1 Release Area #1...........................................................................................3-2

3.5.2 Release Area #2...........................................................................................3-2

3.5.3 Release Area #3...........................................................................................3-2

3.5.4 Release Area #4...........................................................................................3-3

3.5.5 Release Area #5...........................................................................................3-3

3.5.6 Release Area #6...........................................................................................3-3

3.5.7 Release Area #7...........................................................................................3-3

3.5.8 Gulfport-Biloxi International Airport...............................................................3-3

3.5.9 Gulfport South WWTP..................................................................................3-4

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

6.5.3 AOI 3 Conclusions........................................................................................6-5

6.6 AOI 4.......................................................................................................................6-5

6.6.1 AOI 4 Soil Analytical Results .......................................................................6-5

6.6.2 AOI 4 Groundwater Analytical Results .........................................................6-5

6.6.3 AOI 4 Conclusions........................................................................................6-5

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

7.1.4 AOI 4 ............................................................................................................7-3

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

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

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

7.2.3 AOI 3 ............................................................................................................7-4

7.2.4 AOI 4 ............................................................................................................7-4

7.3 Surface Water and Sediment Exposure Pathway...................................................7-4

7.3.1 AOI 1 ............................................................................................................7-4

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

7.3.3 AOI 3 ............................................................................................................7-5

7.3.4 AOI 4 ............................................................................................................7-5

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. Field Change Requests

B4. Nonconformance and Corrective Action Reports

B5. Survey Data

Appendix C Photographic Log

Appendix D TPP Meeting Minutes

Appendix E Boring Logs

Appendix F Analytical Results

Appendix G Laboratory Reports

Figures

Figure 2-1 Facility Location

Figure 2-2 Facility Topography

Figure 2-3 Groundwater Features

Figure 2-4 Groundwater Elevations, May 2022

Figure 2-5 Surface Water Features

Figure 3-1 Areas of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOA Detections in Soil

Figure 6-2 PFOS Detections in Soil

Figure 6-3 PFBS Detections in Soil

Figure 6-4 PFHxS Detections in Soil

Figure 6-5 PFNA Detections in Soil

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

Figure 6-7 PFHxS and PFNA Detections in Groundwater

Figure 7-1 Conceptual Site Model, AOI 1

Figure 7-2 Conceptual Site Model, AOI 2

Figure 7-3 Conceptual Site Model, AOI 3

Figure 7-4 Conceptual Site Model, AOI 4

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

amsl above mean sea level

ANG Air National Guard

AOI Area of Interest

ARNG Army National Guard

AVCRAD Aviation Classification Repair Activity Depot

bgs below ground surface 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CoC chain of custody

CRTC Combat Readiness Training Center

DA Department of the Army

DoD Department of Defense

DPT direct push technology

DQO data quality objective

DUA data usability assessment

EDRTM Environmental Data Resources, Inc.TM

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

FedEx Federal Express

FTA Fire Training Area

GPS Global positioning system

GPRS Ground Penetrating Radar Systems, LLC

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

MSANG Mississippi Air National Guard

MSARNG Mississippi Army National Guard

NELAP National Environmental Laboratory Accreditation Program

ng/L nanograms per liter

OSD Office of the Secretary of Defense

OWS oil/water separator

PA Preliminary Assessment

PFAS per- and polyfluoroalkyl substances

PFBS perfluorobutanesulfonic acid
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PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PID photoionization detector

PQAPP Programmatic UFP-QAPP

PVC polyvinyl chloride

QA quality assurance

QAPP Quality Assurance Project Plan

QC quality control

QSM Quality Systems Manual

SI Site Inspection

SL screening level

SOP standard operating procedure

TOC total organic carbon

TPP Technical Project Planning

UFP Uniform Federal Policy

US United States

USACE United States Army Corps of Engineers

USCS Unified Soil Classification System

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service

VSI Visual Site Inspection

WWTP Waste Water Treatment Plant
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Executive Summary

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

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

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

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

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

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

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

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

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

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

used, stored, disposed, or released historically (see Table ES-2). 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 Gulfport Aviation Classification Repair Activity Depot (AVCRAD) in Gulfport, 

Mississippi and determined further evaluation under the Comprehensive Environmental 

Response, Compensation, and Liability Act (CERCLA) is warranted for AOI 1, AOI 2, AOI 3, and 

AOI 4. The Gulfport AVCRAD will also be referred to as the “facility” throughout this document.

The AVCRAD is located within the City of Gulfport, Harrison County, on the coast of Mississippi.

Located on Gulfport-Biloxi International Airport property, the AVCRAD facility is co-located with 

the Air National Guard Combat Readiness Training Center (CRTC). The AVCRAD and the CRTC 

are tenants under lease from Gulfport-Biloxi Regional Airport Authority until June 2066. At present, 

AVCRAD includes approximately 33 acres of land and operates as a full Army aviation 

maintenance depot facility. 

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

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 AOI 1, AOI 2, AOI 3, and AOI 4.

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

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

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

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

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

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

Analyteb

Residential

(Soil)

(μg/kg)a 

0-2 feet bgs

Industrial/ Commercial 

Composite Worker

(Soil)

(μg/kg)a 

2-15 feet bgs

Tap Water

(Groundwater) 

(ng/L)a

PFOA 19 250 6 

PFOS 13 160 4 

PFBS 1,900 25,000 601 

PFHxS 130 1,600 39

PFNA 19 250 6 

Notes:

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

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

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

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

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

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

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

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

AOI Potential 

Release Area

Soil –

Source 

Area

Groundwater – 

Source Area

Future 

Action

1 New Paint Hangar Proceed to 

RI 

2 Main Hangar and Tank 

Room

Proceed to 

RI 

3 Mississippi ANG 

Aircraft Parking Ramp

Proceed to 

RI

4 Old Aircraft Staging 

Ramp

Proceed to 

RI 

Notes: ANG = Air National Guard; AOI = Area of Interest; N/A = not applicable; RI = Remedial Investigation

Legend:

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected
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1. Introduction

1.1 Project Authorization

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

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

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

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

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

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

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

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

acid (PFBS) at ARNG facilities nationwide. The ARNG performed this SI at the Aviation 

Classification Repair Activity Depot (AVCRAD) in Gulfport, Mississippi. The AVCRAD 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 the AVCRAD (AECOM Technical Services, Inc. [AECOM], 2022) that

identified four 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

The AVCRAD is located within the City of Gulfport, Harrison County, on the coast of Mississippi 

(Figure 2-1). Located on Gulfport-Biloxi International Airport property, the AVCRAD facility is colocated with the Air National Guard (ANG) Combat Readiness Training Center (CRTC). The 

AVCRAD and the ANG CRTC are tenants under lease from Gulfport-Biloxi Regional Airport 

Authority until June 2066. At present, AVCRAD includes approximately 33 acres of land and 

operates as a full Army aviation maintenance depot facility. The Mississippi ARNG (MSARNG)

has been occupying the present location since 1989. Prior to 1989, the MSARNG occupied an

army aviation support facility (AASF) on the south end of the taxiway. The former AASF property 

is still used by the MSARNG, and the buildings are used as a facility maintenance shop and 

armory.

2.2 Facility Environmental Setting

The AVCRAD is located within the Gulf Coastal Plain, less than 3 miles from the Gulf Coast of 

Mississippi. The Coastal Plain is a gently sloping area of unconsolidated fluvial and deltaic 

sediments. The topography at the facility is generally flat (Figure 2-2), and elevations at the facility 

range from approximately 22 to 26 feet above mean sea level (amsl). 

2.2.1 Geology

The facility is underlain by the unconsolidated sediments of the Gulf Coast Plain, which were 

deposited during the transgressive late Pleistocene Sangamonian Interglacial Stage. At the 

beginning of the coastal transgression, sea level stood at a much lower elevation than it does 

today. The facility is directly underlain by the late Pleistocene-aged Prairie Formation and is 

characterized as a 14.7 to 39 feet-thick wedge of alluvial deposits. The Prairie Formation 

(previously described as the Pamlico Sand Formation) interfingers with the Biloxi Formation, 

which was deposited during sea level rise. The Biloxi Formation consists of muddy and sandy 

marine and estuarine sediments that range up to 33 feet in thickness. The Gulfport Formation 

barrier island progradation coincided with a coalescing of Prairie Formation floodplains, which 

created an interfingering of the two units. The sea level eventually exceeded modern levels before 

it fell again approximately 122,000 to 125,000 years ago. During this time, barrier strandplains 

built out seaward from the edge of the Prairie Coastal Plain. Below the Sangamonian sediments 

lie undifferentiated alluvium and Neogene fluvial siliclastic sediments. The Prairie and Biloxi 

formations are underlain by the Citronelle, Graham Ferry, and Pascagoula formations (Otvos, 

2001). The geologic units are depicted on Figure 2-3.

Direct push soil borings were completed during the SI at depths ranging between 8 to 24 feet 

below ground surface (bgs). The soil borings generally encountered silts, clays, and sands in the 

unconsolidated sediments. Observed sands were generally fine- to very-fined grained with 

varying amounts of fines (silts and clays). Silts were observed in all boreholes and contained 

varying amounts of clay and sand. Clay was observed in all borings, except AOI03-01, at depths 

ranging from 2 to 14 feet bgs and ranging in thickness from 2 to 19 feet. The clay contained 

varying amounts of sand and silt.

Samples for grain size analyses were collected at location AOI03-01 and analyzed via American 

Society for Testing and Materials (ASTM) Method D-422. The results indicate that the soil 

samples are comprised primarily of clay (32.85 percent [%]), silt (37.19%), and fine sand 

(29.41%). These results and facility observations are consistent with the reported depositional 
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environment of the region. Boring logs are presented in Appendix E and grain size results are 

presented in Appendix F.

2.2.2 Hydrogeology

Two major aquifer systems, the Mississippi embayment and the coastal lowlands aquifer systems, 

occur in the Gulf Coast of Mississippi. The coastal lowlands aquifer is present in the southern 

third of the state, which includes AVCRAD. In southern Mississippi, the coastal lowlands aquifer 

system is more than 5,000 feet-thick and is composed of several individual aquifers and confining 

units. The base of the coastal lowlands aquifer system is a thick sequence of marine clays of the 

Jackson and Vicksburg Groups, which outcrop across the middle of Mississippi. The facility is 

located to the south of a principle regional recharge area and just to the east of a principle regional 

discharge area that is related to the flow of the Mississippi River (Grubb, 1986).

The individual primary aquifers in the Gulfport area are (from youngest to oldest) the Citronelle,

Graham Ferry, Pascagoula, Hattiesburg, and Catahoula aquifers, which consist of thick, lenticular 

beds of sand or gravel that are not continuous over large areas. The groundwater is primarily 

sourced from the Graham Ferry and the Pascagoula aquifers and are used for domestic, 

industrial, and public water supply in the area. The Graham Ferry and Pascagoula aquifers include 

confining clay layers and contain well fields operated by the City of Gulfport for water supply to 

the facility and surrounding areas (BB&E, 2016; Leidos, 2019). The Citronelle aquifer was not 

identified in the previous studies at the ANG CRTC and may be absent in the vicinity of AVCRAD 

(Leidos, 2019). 

The water table aquifer underlying the facility (also referred to as the Pamlico aquifer) ranges from 

0 to 75 feet in thickness. Historically, the aquifer was locally used for irrigation and limited water 

supply; however, it has become contaminated with sewage and other contaminants from various 

sources in the general Gulfport area, making it unsuitable for drinking water (Brown et al., 1944; 

Leidos, 2019). During a 2019 SI at the adjacent ANG CRTC facility, groundwater levels were 

measured at depths of 1.95 feet bgs to 6.25 feet bgs. The groundwater flow direction is generally 

north-northwest towards Bayou Bernard (Leidos, 2019).

Drinking water for AVCRAD is drawn from a city municipal supply, and the Environmental Data 

Resources, Inc.TM (EDRTM) report lists two City of Gulfport public supply wells approximately 

1,400 feet east-southeast of the southern part of the facility screened within the Graham Ferry 

aquifer with depths of 645 and 740 feet. There are multiple domestic drinking water wells listed 

within 1 mile to the north of the facility boundary. These wells are generally drilled at depths of 

170 to 220 feet bgs (EDRTM, 2019). Additionally, several wells of unknown use are located within 

4 miles of the facility and are screened at depths of less than 75 feet bgs (Mississippi Automated 

Resource Information System, 2009).

Depths to water measured in July 2021 during the SI ranged from 0.88 to 5.13 feet bgs. 

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

groundwater flow direction at the facility is primarily to the northwest.

2.2.3 Hydrology

The AVCRAD lies within the Bernard Bayou-Big Lake Watershed. Two drainage ditches direct 

surface water and stormwater off-site to the north via Outfalls 002 and 003. Stormwater in the 

eastern portion of the facility is conveyed to the eastern facility boundary near Washington Avenue 

via Outfall 001. There is a pond in the northeast corner of the facility that is potentially used for 

stormwater and does not appear to be a permanent feature. The hangar floor drains flow to an 

oil/water separator (OWS) prior to discharging to the sanitary sewer. The sanitary sewer flows to 

the Gulfport South Wastewater Treatment Plant (WWTP). The AVCRAD does not use reclaimed 

water for irrigation or biosolids/biosolid derived fertilizer at the facility.
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The primary drainage in the area is Bayou Bernard, about 0.5 miles to the north. The bayou drains 

east to Big Lake and eventually to the Mississippi Sound and the Gulf of Mexico. The upgradient 

Brickyard Bayou flows towards the east about 1 mile south of the facility and joins with Bayou 

Bernard before entering into Big Lake. Bayou Bernard, Big Lake, and Brickyard Bayou are all 

used recreationally for fishing. Surface water features are presented on Figure 2-5.

2.2.4 Climate

The Gulfport, Mississippi climate is humid and subtropical, and the annual mean temperature is 

68.25 degrees Fahrenheit (°F). The average high temperature in Gulfport, Mississippi is 77.1°F,

and the average low temperature is 59.4°F; the mean annual precipitation is 65.19 inches of rain 

(WorldClimate, 2022). 

2.2.5 Current and Future Land Use

At present, the AVCRAD has a total land area of approximately 33 acres. The primary mission of 

the facility is to provide aircraft maintenance, component rebuilding, and painting. The facility 

buildings provide space for the main operations and storage. Land use surrounding the facility is 

a mixture of residential and industrial and includes the co-located ANG CRTC and Gulfport-Biloxi 

International Airport. The northern tip of the facility is used as a golf driving range and is fenced 

off from the rest of the facility. Reasonably anticipated future land use is not expected to change 

from the current land use.

2.2.6 Sensitive Habitat and Threatened/ Endangered Species 

A wildlife survey has not occurred at the facility, and the facility does not have any significant areas 

of habitat. The following species have not been identified at the facility but may be present in the 

surrounding area. The following amphibians, birds, fish, insects, mammals, and reptiles are

federally endangered, threatened, proposed, and/ or are listed as candidate species in Harrison 

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

• Amphibians: Dusky gopher frog, Rana sevosa (endangered)

• Birds: Red knot, Calidris canutus rufa (threatened); Red-cockaded woodpecker, Picoides 

borealis (endangered); Eastern Black rail, Laterallus jamaicensis (threatened); Piping 

Plover, Charadrius melodus (threatened)

• Fishes: Gulf sturgeon, Acipenser oxyrinchus (threatened)

• Insects: Monarch butterfly, Danaus plexippus (candidate)

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

Myotis lucifugus (under review); West Indian Manatee, Trichechus manatus (threatened)

• Reptiles: Kemp's ridley sea turtle, Lepidochelys kempii (endangered); Loggerhead sea 

turtle, Caretta caretta (threatened); Alabama red-bellied turtle, Pseudemys alabamensis

(endangered); Leatherback sea turtle, Dermochelys coriacea (endangered); Gopher 

tortoise, Gopherus polyphemus (threatened); Hawksbill sea turtle, Eretmochelys imbricata

(endangered); Black pinesnake, Pituophis melanoleucus lodingi (threatened)

2.3 History of PFAS Use

Five potential release areas were identified in the PA where AFFF may have been used, stored, 

disposed, or released historically at AVCRAD (AECOM, 2020). PFAS-containing materials were 

potentially released to surface soil within the boundary of the facility and to the sanitary sewer
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AVCRAD, Gulfport, Mississippi

AECOM 2-4

through fire suppression system testing, accidental leaks and spills, nozzle testing, and any 

potential undocumented releases. The potential release areas were grouped into four AOIs based 

on proximity to one another and presumed groundwater flow. Descriptions of each AOI are further 

presented in Section 3.
Mississippi 

Sound

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

JH

10/3/2022

10/3/2022

Site Inspection at Gulfport AVCRAD, MS

1:126,720

10/3/2022 ­ Figure 2-1 PM CM 10/3/2022

12420 Milestone Center Drive

Germantown, MD 20876

Facility Location

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

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

^_

Gulfport AVCRAD

PROJECT

0 1 2 4

Miles

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AECOM 2-5
CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

JH

1/4/2023

1/4/2023

Site Inspection at Gulfport AVCRAD, MS

-

1/4/2023

1:24,000 Figure 2-2 PM CM 1/4/2023

12420 Milestone Center Drive

Germantown, MD 20876

Facility Topography

Base Map: USGS The National Map: National

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PROJECT

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Bayou Bernard

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Turkey Creek

0 0.5 1 2

Miles

Legend

Facility Boundary

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Direction

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Figure 2-3

CLIENT

REVISED

SCALE

10/3/2022 MS

JH

10/3/2022

10/3/2022

ARNG

GIS BY

CHK BY

Site Inspection at Gulfport AVCRAD, MS

PM CM 10/3/2022

1:63,360 ­ 12420 Milestone Center Drive

Germantown, MD 20876

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri

Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

PROJECT

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THIS PAGE INTENTIONALLY BLANK

COM 2-8
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CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

JH

4/4/2023

4/4/2023

Site Inspection at Gulfport AVCRAD, MS

4/4/2023

1:5,400 ­ Figure 2-4 PM CM 4/4/2023

12420 Milestone Center Drive

Germantown, MD 20876

Groundwater Elevations,

May 2022

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

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

PROJECT

Groundwater elevations in ft NAVD88.

*not used in contouring.

AECOM 2-9
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 2-10

THIS PAGE INTENTIONALLY BLANK
Mississippi Sound

Big Lake

Fritz Creek-Biloxi

River Watershed

Flat Branch-Bernard

Bayou Watershed

Bernard

Bayou-Big Lake

Watershed

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Pass-Mississippi

Sound Watershed

B iloxi River

Turkey Creek

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0 0.5 1 2

Miles

Legend

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Location

Facility Boundary

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Direction

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Figure 2-5

CLIENT

REVISED

SCALE

12/22/2022 MS

JH

12/22/2022

12/22/2022

ARNG

GIS BY

CHK BY

PROJECT Site Inspection at Gulfport AVCRAD, MS

PM CM 12/22/2022

1:63,360 ­ 12420 Milestone Center Drive

Germantown, MD 20876

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri

Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

!@

!@

!@

Pond

Outfall

001

Outfall 002

Outfall 003

AECOM 2-11
THIS PAGE INTENTIONALLY BLANK

COM 2-12
Site Inspection Report

AVCRAD, Gulfport, Mississippi

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, five potential release areas were 

identified at the AVCRAD and grouped into four AOIs (AECOM, 2020). The potential release areas 

are shown on Figure 3-1.

3.1 AOI 1 Release Area A

AOI 1 Release Area A encompasses the New Paint Hangar, where a large release of Jet-X 

occurred in 2018 during a full test of the fire suppression system. It was reported that the Jet-X 

foam did not escape the hangar and was drained through the floor drains to the OWS, which is 

located behind the Main Hangar on the northeastern side of the New Paint Hangar. The OWS 

subsequently drains to the Gulfport South WWTP via the city sanitary sewer system. Given the 

uncertainty of the chemical composition of Jet-X, relevant compounds may have infiltrated to the 

subsurface via leaks in drains, the OWS, underground wastewater conveyance piping beneath 

the hangar, or along such piping from the facility to the municipal WWTP.

3.2 AOI 2 Release Area B

AOI 2 Release Area B encompasses the Main Hangar and Tank Room. The Main Hangar houses 

a fire suppression system equipped with a 900-gallon Chemguard AFFF tank. During the Visual 

Site Inspection (VSI), staining and corrosion were noted on the exterior of the AFFF tank and the 

floor of the tank room, which feeds to the Main Hangar AFFF suppression system. These 

observations indicate potential AFFF release during the Fall 2018 bladder change. There are 

multiple uncertainties regarding the bladder change process. It is unknown who conducted the 

bladder change, how the AFFF was managed during the change, and whether any AFFF were 

spilled or otherwise discharged during the process. Due to these uncertainties and the visual 

evidence of AFFF released inside the tank room, there is the potential that AFFF has been 

released to the environment. Additionally, a 55-gallon drum of Chemguard AFFF was also 

observed in the tank room at the time of the VSI. 

In October 2020, high winds from Hurricane Zeta caused significant damage to the roof of the 

Main Hangar. The AFFF fire suppression system in the Main Hangar was also damaged. 

Significant impacts to the roof and fire suppression system piping caused AFFF to be released 

into the surrounding environment; however, the majority of AFFF was discharged inside the 

building and captured by floor drains, which lead to the OWS. Although an unknown amount of 

AFFF was released to the environment outside of the building, precipitation and wind continued 

to impact the area in the wake of the hurricane, leaving no visible evidence of AFFF releases.

Immediately following the post-hurricane clean-up of the facility, a contractor pumped and cleaned 

the OWS pit of AFFF and disposed of the foam offsite. 

3.3 AOI 3 Release Area C

AOI 3 Release Area C encompasses the MSANG Aircraft Parking Ramp. The northern portion of 

the MSANG Parking Ramp is bisected by the MSANG-MSARNG property line (approximately at

the central trench drain) that runs northeast to southwest down the middle of the ramp. Therefore, 

the northwestern half of the ramp is situated on the MSARNG property (AOI 3 Release Area C), 

while the southeastern half is situated on the MSANG property (MSANG Release Area 5). In the 

1990s, nozzle testing with AFFF was conducted by MSANG CRTC personnel and is known to 

have occurred on both sides of the Aircraft Parking Ramp (Leidos, 2019).
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The AFFF released on the Aircraft Parking Ramp would have been left to dissipate or enter the 

trench drains on the ramp. Some AFFF may have directly contacted surface soil adjacent to the 

ramp. The northeast to southwest-trending drain leads to an off-facility detention pond and the 

off-facility MSANG Outfall 003. The off-facility detention pond is located approximately 600 feet 

east of AOI 3, and MSANG Outfall 003 is located to the northeast of the facility. During the 2019 

MSANG PFAS SI, relevant compounds were detected in soil, groundwater, sediment, and surface 

water samples collected at MSANG Outfall 003. PFOA and PFOS were detected above the 

groundwater SLs but below the soil SLs (Leidos, 2019). These compounds may have also 

infiltrated through potential cracks and seams in the Aircraft Parking Ramp and into the 

subsurface soil or shallow groundwater. 

3.4 AOI 4 Release Areas D & E

AOI 4 Release Areas D and E encompasses the Old Aircraft Staging Ramp; Tri-MaxTM extinguisher 

units were historically staged in this area. Given a lack of information prior to 1991 and uncertainty 

regarding the maintenance of these units, there is the potential for PFAS to have been released 

into the environment. 

3.5 Adjacent Sources

Nine off-facility, potential sources not under control of the MSARNG were identified adjacent to 

the AVCRAD during the PA. These sources include release areas identified in a Mississippi Air 

National Guard (MSANG) SI Report for the Gulfport CRTC (Leidos, 2019). The adjacent potential 

sources are shown on Figure 3-1 and described in the following sections for informational 

purposes only and will not be investigated as part of this SI.

3.5.1 Release Area #1

The MSANG Building 75 (Aircraft Hangar) is located to the south and approximately 80 feet 

upgradient of the AVCRAD facility boundary. An AFFF suppression system was installed in the 

hangar in 2002. The suppression system consists of a 1,200-gallon AFFF tank and additional 

AFFF storage containers. A release of AFFF was reported to likely have occurred during testing 

of the system after installation. Additionally, a 2009 aircraft crash into the hangar triggered an 

AFFF release of unknown quantity. Lastly, a small release of AFFF was reported during pipeline 

maintenance in 2013. During the MSANG SI, PFOA, PFOS, PFHxS, and PFNA exceeded the 

SLs in groundwater (Leidos, 2019).

3.5.2 Release Area #2

MSANG Building 77 was built in 1957 and operated as the CRTC Fire Station until it was 

demolished in 2008, and it is located upgradient and approximately 820 feet south of the AVCRAD

facility boundary. During its operation, Building 77 stored AFFF on trucks and in drums. The 2019 

SI reported that on one occasion, a drum of AFFF ruptured outside of the building. No other known 

releases of AFFF occurred at Building 77 (Leidos, 2019).

During the MSANG SI, groundwater and soil samples for Release Area #2 were co-located with 

Release Area #3. In groundwater, PFOA, PFOS, PFHxS, PFNA, and PFBS exceeded their SLs. 

Additionally, PFOS in soil exceeded the SL (Leidos, 2019).

3.5.3 Release Area #3

The MSANG Building W-1 (Former Warehouse) is located approximately 1,000 feet upgradient 

of the AVCRAD facility boundary, to the south. Building W-1 was built in 1957, and surplus AFFF 
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was likely stored at the building before the building was demolished in 2007. The MSANG SI at 

the CRTC evaluated Release Area #3 with Release Area #2 (Leidos, 2019). See Section 3.5.2

for results from the MSANG SI.

3.5.4 Release Area #4

MSANG Building 66 was built in 2008 to replace Building 77 as the Fire Station, and it is located 

south and approximately 0.25-mile upgradient of the AVCRAD facility boundary. Historically and 

presently, multiple firetrucks hold AFFF at the station, in addition to three 500-gallon AFFF tanks 

that supply a gravity-fed refill system for the trucks. AFFF drips slowly into secondary containment 

from these tanks. Vehicles that hold AFFF are washed in the parking bays or outside on the west 

side of the building. During the MSANG SI, PFOA, PFOS, PFHxS, and PFNA exceeded the SLs 

in groundwater. (Leidos, 2019).

3.5.5 Release Area #5

The MSANG Aircraft Parking Ramp is located along the southeast boundary of the facility, 

upgradient from the majority of the remaining AVCRAD land. Ownership of the northeast trending 

segment of the ramp is split between the MSANG and the MSARNG. Section 3.3 details the 

nozzle testing that occurred at Release Area C.

Additionally, line purging of Aircraft Rescue and Firefighting (ARFF) vehicles that carried AFFF 

was performed on the Aircraft Parking Ramp in the area of MSANG Building 77 (Former Fire 

Station) and Building W-1 (Former Warehouse), as discussed above. Foam expended on the 

MSANG Aircraft Parking Ramp by CRTC personnel would have been left to dissipate or drain into 

the trench drain in the middle of the ramp. This trench drain leads to a detention pond and an 

outfall off-site to the northeast of the AVCRAD facility boundary. During the MSANG SI at the 

CRTC in 2019, PFOA, PFOS, and PFHxS exceeded their SLs in groundwater near this outfall 

(Leidos, 2019).

3.5.6 Release Area #6

The former AASF was in operation from 1974 to the mid-1990s and consisted of multiple hangars 

off the south end of the taxiway. The property is still used by the MSARNG as a facility 

maintenance shop and armory. No information was obtained during the PA regarding the potential 

use, storage, or management of AFFF at this facility. 

3.5.7 Release Area #7

The former and current MSANG fire training areas (FTAs) (used from 1972 to 1988 and since 

1999, respectively) are located approximately 0.8-miles to the west of AVCRAD. During the 

MSANG SI, PFOA, PFOS, PFHxS, and PFNA exceeded their SLs in groundwater (Leidos, 2019). 

Additionally, PFOS exceeded the SL in surface soil.

3.5.8 Gulfport-Biloxi International Airport

The AVCRAD is located along the northeast corner of the Gulfport-Biloxi International Airport. 

Airport personnel were not interviewed during the PA because the focus of the assessment was 

to evaluate potential releases related to activities and sources at the MSARNG properties, not 

formally assess adjacent sources. Therefore, it is not known if AFFF is used or stored at the airport 

currently or historically. Because the presence of AFFF at the airport cannot be confirmed, 

Gulfport-Biloxi International Airport has been identified as a potential off-site source area.
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3.5.9 Gulfport South WWTP

The Gulfport South WWTP is located immediately to the north of the facility. WWTPs can be 

secondary sources depending on the areas that they serve. WWTP biosolids have specifically 

been found to be secondary sources of contamination. Because WWTP personnel were not 

interviewed during the VSI, it is unknown where and how the biosolids from the WWTP are treated 

or disposed of. It is known that the WWTP discharges effluent to local streams. As such, the 

WWTP could be a potential adjacent source.
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4. Project Data Quality Objectives

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

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

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

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

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

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

AOIs.

4.1 Problem Statement

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

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

SLs are presented in Section 6.1 of this report.

4.2 Information Inputs

Primary information inputs included:

• The PA for AVCRAD, Gulfport, Mississippi (AECOM, 2020);

• The PA for the adjacent MSANG CRTC in Gulfport, Mississippi (BB&E, 2016);

• Analytical data from samples collected as part of the SI at the adjacent MSANG CRTC in 

Gulfport, Mississippi (Leidos, 2019);

• 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, 2022a); 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 laterally 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). The scope of the SI was vertically bounded by the top of groundwater. Field activities were 

conducted in the springtime, before the start of hurricane season.

4.4 Analytical Approach

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

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

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

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

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

4.5 Data Usability Assessment

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

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

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, 2022a).
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5. Site Inspection Activities

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

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

in accordance with the following approved documents:

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

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

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

• Final Preliminary Assessment Report, 1108th Theatre Aviation Sustainment Maintenance 

Group (TASMG), Gulfport, Mississippi dated September 2020 (AECOM, 2020);

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

Aviation Classification Repair Activity Depot, Gulfport, Mississippi dated May 2022

(AECOM, 2022a); and

• Final Site Safety and Health Plan, Aviation Classification Repair Activity Depot, Gulfport, 

Mississippi dated May 2022 (AECOM, 2022b).

The SI field activities were conducted from 23 May 2022 to 25 May 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, 2021a), 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-five (25) soil samples from 13 boring locations;

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

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

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

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

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

in Appendix B1. Sampling forms are provided in Appendix B2, a Field Change Request form is 

provided in Appendix B3, a Nonconformance and Corrective Action Report is provided in 

Appendix B4, and land survey data 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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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 22 April 2022, 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, MSARNG, USACE, Mississippi Department of

Environmental Quality (MDEQ), and representatives familiar with the facility, the regulations, and 

the community. 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, 2022a).

A TPP Meeting 3 will be held [date to be determined] to discuss the results of the SI. Meeting 

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

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

5.1.2 Utility Clearance

Both AECOM and their drilling subcontractor, Walker-Hill Environmental, placed a ticket with the 

Mississippi 811 “Call Before You Dig” utility clearance contractor to notify them of intrusive work 

on 17 May 2022. Because Mississippi 811 locators do not locate private utilities, such as those 

belonging to the AVCRAD, AECOM contracted Ground Penetrating Radar Systems, LLC (GPRS), 

a private utility location service, to perform utility clearance. GPRS performed utility clearance of 

the proposed boring locations on 23 May 2022 with input from the AECOM field team and 

AVCRAD 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

Two potable water sources at the AVCRAD were sampled on 24 February 2022 to assess usability 

for decontamination of drilling equipment. Samples were collected from a spigot on the northeast 

side of the Main Hangar (GUL-DECON-01) and from the southwest side of Building #3 (GULDECON-02). Results of the sample collected at the spigot at Building #3 (GUL-DECON-02) 

confirmed this source to be acceptable for use in this investigation; therefore, the spigot was 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 sample associated with the 

wash rack spigot source used during the SI are provided in Appendix F. A discussion of the 

results is presented in the DUA (Appendix A).

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

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

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

(AECOM, 2022a). Prior to the start of field work each day, a Sampling Checklist was completed 

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

member regarding the allowable materials within the sampling environment.

5.2 Soil Borings and Soil Sampling

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

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

SI QAPP Addendum (AECOM, 2022a). A GeoProbe® 7822DT macrocore sampling system was 

used to collect continuous soil cores to the target depth. A hand auger was used to collect soil 
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from the top five feet of the boring, in accordance with AECOM utility clearance procedures. The 

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

Soil borings advanced using DPT were sampled in three discrete intervals within the vadose zone 

for chemical analysis: one surface soil sample (0 to 2 feet bgs), one subsurface soil sample 

approximately 2 feet above the groundwater table, and one subsurface soil sample at the midpoint between the surface and the groundwater table. However, at multiple locations shallow 

groundwater was encountered and only two discrete soil samples were collected: one surface soil 

sample (0 to 2 feet bgs) and one subsurface soil sample approximately 2 feet above the 

groundwater table. This field change is further discussed in Section 5.8. Additionally, five surface 

soil samples (0 to 2 feet bgs) were collected using a hand auger.

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.

Direct push soil borings were completed during the SI at depths ranging between 8 to 24 feet bgs. 

The soil borings generally encountered silts, clays, and sands in the unconsolidated sediments. 

Observed sands were generally fine- to very-fined grained with varying amounts of fines (silts and 

clays). Silts were observed in all boreholes and contained varying amounts of clay and sand. Clay 

was observed in all borings, except AOI03-01, at depths ranging from 2 to 14 feet bgs and ranging 

in thickness from 2 to 19 feet. The clay contained varying amounts of sand and silt.

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), pH (USEPA Method 9045D), and grain size (ASTM 

Method D-422) in accordance with the SI QAPP Addendum (AECOM, 2022a).

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, 2022a) using bentonite chips at completion 

of sampling activities.

5.3 Temporary Well Installation and Groundwater Grab Sampling

Temporary wells were installed using a GeoProbe® 7822DT macrocore sampling system. Once 

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

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

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

locations. The screen intervals for the temporary wells are provided in Table 5-2.
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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 bladder pump with PFAS-free HDPE tubing.

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

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

dissolved oxygen, turbidity, 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, 2022a).

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

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

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

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

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

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

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

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

location was patched to match existing surrounding conditions.

5.4 Synoptic Water Level Measurements

A synoptic groundwater gauging event was performed on 25 May 2022. Groundwater elevation 

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

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

map is provided in Figure 2-4. The groundwater elevation collected at GUL-04 was not used in 

constructing the groundwater contours, as the groundwater elevation was much lower than the 

nearby wells. Groundwater elevation data are provided in Table 5-2.

5.5 Surveying

The northern side of seven out of the eleven well casings were surveyed by Mississippi-licensed 

land surveyors following guidelines provided in the SOPs provided in the SI QAPP Addendum 

(AECOM, 2022a). Survey data from the newly installed wells on the facility were collected on 25

May 2022 in the applicable Universal Transverse Mercator zone projection World Geodetic 

System 84 datum (horizontal) and North American Vertical Datum 1988 (vertical). The surveyed 

well data are provided in Appendix B5. Four wells, GUL-01, GUL-02, GUL-03, and AOI02-02, 

were pulled in error prior to the survey team arriving at the locations; this is further described in 

Section 5.8 and in a Nonconformance and Corrective Action Report in Appendix B4.

5.6 Investigation-Derived Waste

As of the date of this report, the disposal of investigation-derived waste (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, 2022a) and with the DA Guidance for 

Addressing Releases of PFAS, Q18 (DA, 2018).
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Soil IDW (i.e., soil cuttings) generated during the SI activities were containerized in labeled, 55-

gallon Department of Transportation (DOT)-approved steel drums and left onsite, northeast of the

Main Hanger. ARNG will further manage soil IDW in accordance with the DA Guidance for

Addressing Releases of PFAS, Q18 (DA, 2018). ARNG will coordinate profiling, transportation,

and disposal of the soil IDW under a separate contract.

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

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

left onsite, next to the soil IDW drums. ARNG will further manage liquid IDW in accordance with

the DA Guidance for Addressing Releases of PFAS, Q18 (DA, 2018). Containerized liquid IDW

will be characterized, managed, and disposed of by ARNG (either by offsite disposal or onsite

disposal with treatment, as appropriate) under a separate contract. 

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

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

documentation. The deviations are noted below and are documented in Field Change Request 

Forms (Appendix B3) and Nonconformance and Corrective Action Reports (Appendix B4): 

• According to the SI QAPP Addendum, three soil samples were planned to be collected from 

each soil boring that was converted to a temporary well. All samples were supposed to target 

the soil above the water table in the vadose zone. However, due to shallow groundwater 

encountered at the facility, only two samples could be collected from multiple boreholes. 

This action is documented in a Field Change Request form provided in Appendix B3.

• While the subcontracted licensed surveyors were surveying the temporary wells, a 

miscommunication occurred in which the subcontracted drilling crew started abandoning 

wells prior to them being surveyed. This resulted in four wells not having top of casings 

measured by the survey crew. These wells include: GUL-01, GUL-02, GUL-03, and AOI02-

02. The remaining seven wells were appropriately surveyed, and the measured water level 

data were used to develop the groundwater elevation contour. The groundwater flow 

direction DQO was met using this data and suggests a northwesterly flow direction. This 

action was documented in a Nonconformance and Corrective Action Report provided in 

Appendix B4.

• Two soil samples that were submitted for analysis were not analyzed by the laboratory. 

Sample AOI02-03-SB-02-04 was not analyzed for PFAS or for pH/TOC, and sample AOI03-

01-SB-00-02 was not analyzed for pH/TOC but was analyzed for PFAS. These deviations 

are documented in a Nonconformance and Corrective Action Report provided in Appendix 

B4.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 5-6

THIS PAGE INTENTIONALLY BLANK
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Aviation Classification Repair Activity Depot, Gulfport, Mississippi

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

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

Comments

AOI01-01-SB-00-02 5/24/2022 13:10 0 - 2 x x x

AOI01-01-SB-02-3.5 5/24/2022 13:18 2 - 3.5 x

AOI02-01-SB-00-02 5/24/2022 15:40 0 - 2 x

AOI02-01-SB-02-04 5/24/2022 16:10 2 - 4 x

AOI02-01-SB-04-06 5/24/2022 15:53 4 - 6 x

AOI02-02-SB-00-02 5/23/2022 15:32 0 - 2 x

AOI02-02-SB-02-04 5/24/2022 9:05 2 - 4 x

AOI02-02-SB-02-04-D 5/24/2022 9:05 2 - 4 x FD

AOI02-02-SB-5.5-7.5 5/23/2022 16:32 5.5 - 7.5 x

AOI02-03-SB-00-02 5/24/2022 14:18 0 - 2 x

AOI02-03-SB-02-04 5/24/2022 14:21 2 - 4 x x x Sample lost by the lab*

AOI02-04-SB-00-02 5/25/2022 9:15 0 - 2 x

AOI03-01-SB-00-02 5/23/2022 11:05 0 - 2 x x x pH/TOC not analyzed*

AOI03-01-SB-02-04 5/23/2022 11:08 2 - 4 x

AOI03-01-SB-14-16 5/23/2022 12:10 14 - 16 x

AOI04-01-SB-00-02 5/25/2022 9:03 0 - 2 x

AOI04-01-SB-00-02-MS 5/25/2022 9:03 0 - 2 x MS

AOI04-01-SB-00-02-MSD 5/25/2022 9:03 0 - 2 x MSD

AOI04-01-SB-02-04 5/25/2022 9:10 2 - 4 x x x

AOI04-01-SB-02-04-D 5/25/2022 9:10 2 - 4 x x FD

AOI04-01-SB-02-04-MS 5/25/2022 9:10 2 - 4 x x MS

AOI04-01-SB-02-04-MSD 5/25/2022 9:10 2 - 4 x x MSD

GUL-01-SB-00-02 5/24/2022 11:30 0 - 2 x

GUL-02-SB-00-02 5/24/2022 10:05 0 - 2 x

GUL-02-SB-00-02-D 5/24/2022 10:05 0 - 2 x FD

GUL-02-SB-02-04 5/24/2022 10:10 2 - 4 x

GUL-03-SB-00-02 5/24/2022 9:30 0 - 2 x

GUL-03-SB-00-02-D 5/24/2022 9:30 0 - 2 x FD

GUL-03-SB-00-02-MS 5/24/2022 9:30 0 - 2 x MS

GUL-03-SB-00-02-MSD 5/24/2022 9:30 0 - 2 x MSD

GUL-04-SB-00-02 5/23/2022 13:15 0 - 2 x

GUL-04-SB-13-15 5/23/2022 13:58 13 - 15 x

GUL-04-SB-18-20 5/23/2022 14:25 18 - 20 x

GUL-05-SB-00-02 5/25/2022 10:24 0 - 2 x

GUL-05-SB-02-03 5/25/2022 10:28 2 - 3 x

GUL-06-SB-00-02 5/25/2022 10:48 0 - 2 x

Soil Samples

AECOM 5-7 
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Aviation Classification Repair Activity Depot, Gulfport, Mississippi

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

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

Comments

AOI01-01-GW 5/24/2022 15:05 NA x

AOI01-01-GW-D 5/24/2022 15:05 NA x FD

AOI02-01-GW 5/25/2022 9:30 NA x

AOI02-02-GW 5/24/2022 10:40 NA x

AOI02-03-GW 5/24/2022 16:20 NA x

AOI03-01-GW 5/23/2022 14:35 NA x

AOI03-01-GW-D 5/23/2022 14:35 NA x FD

AOI03-01-GW-MS 5/23/2022 14:35 NA x MS

AOI03-01-GW-MSD 5/23/2022 14:35 NA x MSD

AOI04-01-GW 5/25/2022 10:22 NA x

GUL-01-GW 5/24/2022 13:50 NA x

GUL-02-GW 5/24/2022 12:50 NA x

GUL-03-GW 5/24/2022 11:36 NA x

GUL-04-GW 5/23/2022 15:45 NA x

GUL-05-GW 5/25/2022 11:50 NA x

GUL-05-GW-D 5/25/2022 11:50 NA x FD

GUL-FRB-01 5/23/2022 16:24 NA x

GUL-ERB-01 5/24/2022 13:56 NA x Off rig shoe

GUL-ERB-02 5/24/2022 13:45 NA x Off driller's hand auger

GUL-ERB-03 5/25/2022 8:00 NA x Off AECOM hand auger

GUL-DECON-01 2/24/2022 9:55 NA x From spigot at hangar

GUL-DECON-02 2/24/2022 10:40 NA x From spigot at Bldg #3

GUL-DECON-03 5/25/2022 11:25 NA x From rig tank

Notes:

*Samples AOI02-03-SB-02-04 (PFAS and pH/TOC) and AOI03-01-SB-00-02 (pH/TOC) were not analyzed by the laboratory as described in Section 5.8.

ASTM = American Society for Testing and Materials

bgs = below ground surface

ERB = equipment rinsate blank

FD = field duplicate

FRB = field reagent blank

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MS/MSD = matrix spike/ matrix spike duplicate

PFAS = per- and polyfluoroalkyl substances

QSM = Quality Systems Manual

TOC = total organic carbon

USEPA = United States Environmental Protection Agency

Quality Control Samples

Groundwater Samples

AECOM 5-8 
Table 5-2

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

Site Inspection Report, Aviation Classification Repair Activity Depot, Gulfport, Mississippi

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)

1 AOI01-011 12 1 - 11 23.08 18.66 5.30 0.88 17.78

AOI02-011 16 3 - 13 26.99 24.85 7.27 5.13 19.72

AOI02-021,2 16 5 - 15 N/A 18.54 0.35 N/A N/A

AOI02-03 12 2 - 12 24.46 21.11 5.19 1.84 19.27

3 AOI03-011 16 2 - 12 28.43 25.23 4.69 1.49 23.74

4 AOI04-01 12 2 - 12 26.26 23.02 7.15 3.91 19.11

GUL-011,2 8 2 - 7 N/A 13.10 3.59 N/A N/A

GUL-021,2 13 0 - 5 N/A 13.36 1.23 N/A N/A

GUL-031,2 8 1 - 6 N/A 16.88 4.48 N/A N/A

GUL-041 24 5 - 15 19.42 17.10 3.29 0.97 16.13

GUL-05 8 0 - 8 25.66 24.12 3.70 2.16 21.96

Notes:

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

2. Well was abandoned prior to surveying top of casing as described in Section 5.8.

bgs = below ground surface

btoc = below top of casing

NA = not applicable

NAVD88 = North American Vertical Datum 1988

2

Facilitywide

AECOM 5-9 
AECOM 5-10

THIS PAGE INTENTIONALLY BLANK

COM 5-10
?!

?! ?!

?!

?!

"S

?!

?!

?!

?!

?!

?!

"S

AOI 1

AOI 3

AOI 2

AOI 4

GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

GUL-06

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

AOI02-04

0 225 450 900

Feet

Legend

?! Soil Boring/Temporary Monitoring Well

"S Surface Soil Sample

Area of Interest

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

Surface Water Flow Direction

Groundwater Flow Direction

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

JH

4/4/2023

4/4/2023

Site Inspection at Gulfport AVCRAD, MS

4/4/2023

1:5,400 ­ Figure 5-1 PM CM 4/4/2023

12420 Milestone Center Drive

Germantown, MD 20876

Site Inspection

Sample Locations

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

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

PROJECT

AECOM 5-11
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 5-12

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Site Inspection Report

AVCRAD, Gulfport, Mississippi

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 6.6. 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

AVCRAD, Gulfport, Mississippi

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, pH, and grain size sampling.

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

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

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

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

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

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

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

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

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

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

6.3 AOI 1

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

AOI 1: Release Area A. 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

Soil was sampled from surface soil (0 to 2 feet bgs) from boring location AOI01-01 and the 

downgradient borings GUL-01 and GUL-02. Shallow subsurface soil (between 2 to 4 feet bgs)

was sampled from AOI01-01 and GUL-02. Deep subsurface soil was not sampled at AOI 1 due 

to shallow groundwater. 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. 

PFOS, PFHxS, and PFNA were detected in surface soil at all three locations at concentrations 

more than one order of magnitude below the SLs. The maximum detected concentration was 

PFOS at 0.973 J micrograms per kilogram (μg/kg). PFOA and PFBS were not detected in any of 

the surface soil samples.

In subsurface soil, PFOS, PFHxS, and PFNA were detected at concentrations a least two orders 

of magnitude below their SLs at AOI01-01. PFBS and PFOA were not detected at AOI01-01. None 

of the relevant compounds were detected in the downgradient boring GUL-02.

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 well

AOI01-01 and the downgradient facility boundary temporary wells GUL-01 and GUL-02. The 

following exceedances of the SLs were measured:

• PFOA was detected above the SL of 6 nanograms per liter (ng/L), at a concentration of 

48.2 J ng/L.

• PFOS was detected above the SL of 4 ng/L, at concentrations of 368 J ng/L and 10.5 

ng/L at AOI01-01 and GUL-01, respectively.

• PFHxS was detected above the SL of 39 ng/L, at a concentration of 90.9 J ng/L at 

AOI01-01.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 6-3

• PFNA was detected above the SL of 6 ng/L, at a concentration of 22.2 ng/L at AOI01-01.

PFBS was detected below the SL at all locations, with a maximum concentration of 11.6 ng/L at 

AOI01-01. No exceedances of the SLs were detected at GUL-02.

6.3.3 AOI 1 Conclusions

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

PFOA, PFOS, PFHxS, and PFNA were detected in groundwater, at concentrations above their

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

warranted.

6.4 AOI 2

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

AOI 2: Release Area B. 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

Soil was sampled from surface soil (0 to 2 feet bgs) from boring locations AOI02-01 through 

AOI02-04 and the downgradient location GUL-03. Soil was also sampled from the shallow 

subsurface interval (2-foot intervals between from 2 and 7.5 feet bgs) from borings AOI02-01 and 

AOI02-03, although the sample from AOI02-03 was not analyzed by the laboratory (see Section 

5.8) Deep subsurface soil was not sampled at AOI 2 location due to shallow groundwater. 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.

PFOS and PFNA were detected in all five surface soil locations, with concentrations ranging 

between 0.026 J μg/kg to 2.36 μg/kg. PFOA and PFHxS were also detected in surface soil below 

the SLs at four of the five locations, with concentrations ranging from 0.061 J μg/kg to 0.770 J 

μg/kg. PFBS was detected in surface soil several orders of magnitude below the SL at location 

AOI02-04. 

In subsurface soil, PFOS and PFNA were detected in shallow subsurface soil samples at boring 

AOI02-01, with concentrations several orders of magnitude below the SLs. PFOA, PFBS and

PFHxS were not detected in subsurface soil at AOI 2.

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 wells 

AOI02-01 through AOI02-03 and GUL-03. The following exceedances of the SLs were measured:

• PFOA was detected above the SL of 6 ng/L in all four temporary wells at concentrations 

ranging from 11.9 ng/L at AOI02-02 to 59.7 ng/L at AOI02-03. 

• PFOS was detected above the SL of 4 ng/L in three temporary wells at concentrations 

ranging from 5.94 J ng/L at GUL-03 to 41.2 ng/L at AOI02-01.

• PFNA was detected above the SL of 6 ng/L at AOI02-01, with a concentration of 

6.15 ng/L. 

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

maximum concentrations of 11.6 ng/L and 37.3 ng/L detected at AOI02-03.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 6-4

6.4.3 AOI 2 Conclusions

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

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

their SLs. Based on the exceedances of the SLs in groundwater, further evaluation at AOI 2 is 

warranted.

6.5 AOI 3

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

AOI 3: Release Area C. 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.

6.5.1 AOI 3 Soil Analytical Results

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

6-4 summarize the soil results. Soil was sampled from surface soil (0 to 2 feet bgs) from boring 

locations AOI03-01, GUL-04 (located at Outfall 001), and GUL-05. Shallow subsurface soil was 

also sampled from 2 to 4 feet bgs at AOI03-01, from 2 to 3 feet bgs at GUL-05, and from 13 to 15 

feet bgs at GUL-04. Deep subsurface soil (18 to 20 feet bgs) was sampled from boring GUL-04. 

PFOA, PFOS, PFHxS, and PFNA were detected in surface soil, at locations AOI03-01 and 

GUL-05, at concentrations ranging from 0.147 J μg/kg to 5.37 μg/kg. PFHxS was the only relevant 

compound detected at GUL-04.

In shallow subsurface soil, PFOA, PFOS, PFHxS, and PFNA were detected below their SLs, with

concentrations ranging from 0.053 J μg/kg to 1.21 μg/kg. PFBS was not detected in shallow 

subsurface soil at any of the three borings. No relevant compounds were detected in shallow 

subsurface soil at GUL-04. None of the relevant compounds were detected in the deep 

subsurface soil at GUL-04.

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 

AOI03-01, GUL-04, and GUL-05. Temporary well GUL-04 is located near Outfall 001, which 

receives storm water from areas near AOIs 2 and 3. The following exceedances of the SLs were 

measured: 

• PFOA was detected above the SL of 6 ng/L in two wells, at concentrations of 71.9 J 

ng/L and 97.1 J ng/L. 

• PFOS was detected above the SL of 4 ng/L in two wells, at concentrations of 707 J ng/L 

and 2,090 ng/L. 

• PFHxS was detected above the SL of 39 ng/L in two wells, at concentrations of 183 J

ng/L and 229 J ng/L. 

• PFNA was detected above the SL of 6 ng/L in two wells, at concentrations of 17.9 ng/L

and 99.6 J ng/L.

PFBS was detected in all three wells, at concentrations over an order of magnitude below the SL. 

No exceedances of the relevant compounds were observed at GUL-04.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 6-5

6.5.3 AOI 3 Conclusions

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

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

their SLs. Based on the exceedances of the SLs in groundwater, further evaluation at AOI 3 is 

warranted.

6.6 AOI 4

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

AOI 4: Release Areas D & E. 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.

6.6.1 AOI 4 Soil Analytical Results

Soil was sampled from the surface (0 to 2 feet bgs) and shallow subsurface (2 to 4 feet bgs)

intervals at boring location AOI04-01. Deep subsurface soil was not sampled from any AOI 4

location due to shallow groundwater. 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. 

PFOS and PFHxS were detected in surface soil, at concentrations more than one order of 

magnitude below their SLs, with a maximum concentration of 0.134 J- g/kg. In shallow subsurface 

soil, PFOS and PFBS were detected at concentrations several orders of magnitude below the 

SLs. PFOA and PFNA were not detected in either surface or shallow subsurface soil.

6.6.2 AOI 4 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

AOI04-01. The following exceedances of the SLs were observed:

• PFOA was detected in above the SL of 6 ng/L, at a concentration of 7.07 ng/L.

• PFOS was detected above the SL of 4 ng/L, at a concentration of 7.07 ng/L. 

PFBS and PFHxS were detected at concentrations below their SLs. PFNA was not detected in 

groundwater at AOI 4.

6.6.3 AOI 4 Conclusions

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

PFOA and PFOS were detected in groundwater, at concentrations above their SLs. Based on the 

exceedances of the SLs in groundwater, further evaluation at AOI 4 is warranted.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 6-6

THIS PAGE IS INTENTIONALLY BLANK
Table 6-2

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

Site Inspection Report, Gulfport

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 0.022 J ND U ND U ND U ND U ND U

PFHxS 130 0.089 J 0.087 J 0.061 J 0.075 J 0.274 J 0.767 J 0.056 J 0.049 J 0.060 J 0.044 J

PFNA 19 0.021 J 0.171 J 0.105 J 0.271 J 0.213 J 0.147 J ND U ND U 0.026 J ND UJ

PFOA 19 ND U 0.222 J 0.131 J 0.491 J 0.770 J 0.182 J ND U 0.101 J ND U ND U

PFOS 13 0.973 J 2.36 0.071 J 0.267 J 1.20 5.37 0.134 J- 0.333 J 0.155 J 0.131 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

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. D duplicate

DL detection limit

Notes ft feet

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. GUL Gulfport

HQ hazard quotient

ID identification

Limit of Detection (LOD) ranges for relevant compounds: LCMSMS liquid chromatography with tandem mass spectrometry

PFBS: 0.050-0.062 μg/kg LOD limit of detection

PFHxS: 0.100-0.123 μg/kg ND analyte not detected above the LOD

PFNA: 0.050-0.062 μg/kg OSD Office of the Secretary of Defense

PFOA: 0.200-0.246 μg/kg QSM Quality Systems Manual

PFOS: 0.200-0.246 μg/kg 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

AOI01

AOI01-01-SB-00-02

05/24/2022

0-2 ft

AOI02-01-SB-00-02

05/24/2022

0-2 ft

AOI02-02-SB-00-02

05/23/2022

0-2 ft

AOI02-03-SB-00-02

05/24/2022

0-2 ft

AOI02-04-SB-00-02

05/25/2022

0-2 ft 0-2 ft

AOI04

AOI04-01-SB-00-02

05/25/2022

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.

AOI02 Sitewide

GUL-02-SB-00-02-D

05/24/2022

0-2 ft

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

GUL-01-SB-00-02

05/24/2022

0-2 ft

GUL-02-SB-00-02

05/24/2022

0-2 ft

AOI03

AOI03-01-SB-00-02

05/23/2022

AECOM 6-7 
Table 6-2

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

Site Inspection Report, Gulfport

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual

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

PFHxS 130 ND U ND U 0.033 J 0.230 J 0.199 J

PFNA 19 0.026 J 0.025 J ND U 1.23 0.022 J

PFOA 19 ND U ND U ND U 1.34 0.162 J

PFOS 13 0.073 J ND UJ ND U 1.56 0.305 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

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. D duplicate

DL detection limit

Notes ft feet

ND = Analyte not detected above the LOD. LOD values are presented in Appendix F. GUL Gulfport

HQ hazard quotient

ID identification

Limit of Detection (LOD) ranges for relevant compounds: LCMSMS liquid chromatography with tandem mass spectrometry

PFBS: 0.050-0.062 μg/kg LOD limit of detection

PFHxS: 0.100-0.123 μg/kg ND analyte not detected above the LOD

PFNA: 0.050-0.062 μg/kg OSD Office of the Secretary of Defense

PFOA: 0.200-0.246 μg/kg QSM Quality Systems Manual

PFOS: 0.200-0.246 μg/kg Qual interpreted qualifier

SB soil boring

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

Sample ID

Sample Date

Depth

GUL-03-SB-00-02

05/24/2022

0-2 ft

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.

Sitewide

GUL-05-SB-00-02

05/25/2022

0-2 ft

GUL-06-SB-00-02

05/25/2022

0-2 ft

GUL-03-SB-00-02-D

05/24/2022

0-2 ft

GUL-04-SB-00-02

05/23/2022

0-2 ft

Area of Interest

AECOM 6-8
Table 6-3

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

Site Inspection Report, Gulfport

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 ND U ND U 0.030 J ND U ND U

PFHxS 1600 0.066 J ND U ND U ND U ND U ND U 0.108 J ND U ND U ND U

PFNA 250 0.053 J 0.038 J ND U ND U ND U ND U 0.053 J 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 1.49 0.429 J 0.085 J ND U ND U ND U 1.21 0.112 J 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

GUL Gulfport

HQ hazard quotient

Limit of Detection (LOD) ranges for relevant compounds: ID identification

PFBS: 0.053-0.066 μg/kg LCMSMS liquid chromatography with tandem mass spectrometry

PFHxS: 0.105-0.132 μg/kg LOD limit of detection

PFNA: 0.053-0.066 μg/kg ND analyte not detected above the LOD

PFOA: 0.210-0.265 μg/kg OSD Office of the Secretary of Defense

PFOS: 0.210-0.265 μg/kg QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s

Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of

contaminated soil.

AOI02 Sitewide

GUL-04-SB-13-15

05/23/2022

13-15 ft

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

AOI04

AOI04-01-SB-02-04

05/25/2022

2-4 ft

GUL-02-SB-02-04

05/24/2022

2-4 ft

AOI02-02-SB-5.5-7.5

05/23/2022

5.5-7.5 ft

AOI03

AOI03-01-SB-02-04

05/23/2022

2-4 ft

AOI02-02-SB-02-04

05/24/2022

2-4 ft

AOI02-02-SB-02-04-D

05/24/2022

2-4 ft

AOI02-01-SB-02-04

05/24/2022

2-4 ft

AOI02-01-SB-04-06

05/24/2022

4-6 ft

Area of Interest

Sample ID

Sample Date

Depth

AOI01

AOI01-01-SB-02-3.5

05/24/2022

2-3.5 ft

AECOM 6-9
Table 6-3

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

Site Inspection Report, Gulfport

Analyte OSD Screening 

Level a

Result Qual

PFBS 25000 ND U

PFHxS 1600 0.057 J

PFNA 250 0.145 J

PFOA 250 0.109 J

PFOS 160 0.566 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

GUL Gulfport

HQ hazard quotient

Limit of Detection (LOD) ranges for relevant compounds: ID identification

PFBS: 0.053-0.066 μg/kg LCMSMS liquid chromatography with tandem mass spectrometry

PFHxS: 0.105-0.132 μg/kg LOD limit of detection

PFNA: 0.053-0.066 μg/kg ND analyte not detected above the LOD

PFOA: 0.210-0.265 μg/kg OSD Office of the Secretary of Defense

PFOS: 0.210-0.265 μg/kg QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

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

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s

Regional Screening Level Calculator. HQ=0.1, May 2022. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of

contaminated soil.

Area of Interest

Sample ID

Sample Date

Depth

Sitewide

GUL-05-SB-02-03

05/25/2022

2-3 ft

AECOM 6-10
Table 6-4

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

Site Inspection Report, Gulfport

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

Limits of Detection (LODs) for relevant compounds: Acronyms and Abbreviations

PFBS: 0.057 μg/kg AASF Army Aviation Support Facility

PFHxS: 0.114 μg/kg AOI Area of Interest

PFNA: 0.057 μg/kg D duplicate

PFOA: 0.229 μg/kg DL detection limit

PFOS: 0.229 μg/kg ft feet

GUL Gulfport

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

Sitewide

GUL-04-SB-18-20

05/23/2022

18-20 ft

Soil, LCMSMS compliant with QSM 5.3 Table B

AECOM 6-11
Table 6-5

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

Site Inspection Report, Gulfport

Analyte OSD Screening 

Level a

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

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

PFBS 601 11.6 6.74 4.59 2.94 J 11.6 14.2 5.57 3.80 J 2.62 J

PFHxS 39 90.9 J 53.6 J 26.1 13.0 37.3 183 J 72.4 8.70 3.96 J

PFNA 6 22.2 14.6 6.15 2.46 J 4.99 17.9 J 9.16 ND U ND U

PFOA 6 48.2 J 29.6 J 16.0 11.9 59.7 97.1 J 39.2 7.07 3.11 J

PFOS 4 368 J 248 J 41.2 1.96 J 35.2 707 J 500 7.07 10.5

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 AOI Area of Interest

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

DL detection limit

GUL Gulfport

Limit of Detection (LOD) ranges for relevant compounds: GW groundwater

PFBS: 1.91-10.0 ng/L HQ hazard quotient

PFHxS: 2.86-15.0 ng/L ID identification

PFNA: 1.91-10.0 ng/L LCMSMS liquid chromatography with tandem mass spectrometry

PFOA: 1.91-10.0 ng/L LOD limit of detection

PFOS: 1.91-10.0 ng/L ND analyte not detected above the LOD. LOD values are presented in Appendix F.

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual interpreted qualifier

RE re-extracted

USEPA United States Environmental Protection Agency

ng/l nanogram per liter

Sample ID

Sample Date

AOI03-01-GW (RE)

05/23/2022

Sitewide

GUL-01-GW

05/24/2022

AOI02-03-GW

05/24/2022

AOI03-01-GW-D

05/23/2022

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using

USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022 Groundwater screening levels based on residential scenario for direct ingestion of groundwater.

AOI01 AOI02 AOI03 AOI04

AOI04-01-GW

05/25/2022

AOI02-01-GW

05/25/2022

AOI02-02-GW

05/24/2022

AOI01-01-GW

05/24/2022

AOI01-01-GW-D

05/24/2022

Area of Interest

AECOM 6-12
Table 6-5

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

Site Inspection Report, Gulfport

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual

PFBS 601 1.70 J 3.74 J 5.41 10.1 2.69 J

PFHxS 39 1.31 J 11.5 J 25.6 229 J 48.8 J

PFNA 6 ND U ND U ND U 99.6 J 22.9 J

PFOA 6 ND U 40.7 3.64 J 71.9 J 16.4 J

PFOS 4 ND U 5.94 J 1.35 J 2090 J 467 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 AOI Area of Interest

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

DL detection limit

GUL Gulfport

Limit of Detection (LOD) ranges for relevant compounds: GW groundwater

PFBS: 1.91-10.0 ng/L HQ hazard quotient

PFHxS: 2.86-15.0 ng/L ID identification

PFNA: 1.91-10.0 ng/L LCMSMS liquid chromatography with tandem mass spectrometry

PFOA: 1.91-10.0 ng/L LOD limit of detection

PFOS: 1.91-10.0 ng/L ND analyte not detected above the LOD. LOD values are presented in Appendix F.

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual interpreted qualifier

RE re-extracted

USEPA United States Environmental Protection Agency

ng/l nanogram per liter

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

a. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using

USEPA’s Regional Screening Level Calculator. HQ=0.1, May 2022 Groundwater screening levels based on residential scenario for direct ingestion of groundwater.

Sitewide

GUL-05-GW

05/25/2022

GUL-05-GW-D

05/25/2022

GUL-03-GW

05/24/2022

GUL-04-GW

05/23/2022

Area of Interest

Sample ID

Sample Date

GUL-02-GW

05/24/2022

AECOM 6-13
THIS PAGE IS INTENTIONALLY BLANK
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

GUL-06

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

AOI02-04

AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-01

GUL-04

AOI02-02

0 225 450 900

Feet

Shallow Intermediate Deep

-

Figure 6-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

1/4/2023

1/4/2023

1/4/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

1/4/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

PFOA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

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

AECOM 6-15
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

GUL-06

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

AOI02-04

AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-01

GUL-04

AOI02-02

0 225 450 900

Feet

Shallow Intermediate Deep

-

Figure 6-2

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

1/4/2023

1/4/2023

1/4/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

1/4/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

PFOS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

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

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

PFOS Results (μg/Kg)

ND

>ND - 13

>13 - 160

>160 - 1,600

>1,600

AECOM 6-16
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

GUL-06

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

AOI02-04

AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-01

GUL-04

AOI02-02

0 225 450 900

Feet

Shallow Intermediate Deep

-

Figure 6-3

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

1/4/2023

1/4/2023

1/4/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

1/4/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

PFBS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

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

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

PFBS Results (μg/Kg)

ND

>ND - 10

>10 - 1,900

>1,900 - 25,000

>25,000

AECOM 6-17
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

GUL-06

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

AOI02-04

AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-01

GUL-04

AOI02-02

0 225 450 900

Feet

Shallow Intermediate Deep

-

Figure 6-4

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

1/4/2023

1/4/2023

1/4/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

1/4/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

PFHxS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

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

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

PFHxS Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

AECOM 6-18
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

GUL-06

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

AOI02-04

AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-01

GUL-04

AOI02-02

0 225 450 900

Feet

Shallow Intermediate Deep

-

Figure 6-5

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

1/4/2023

1/4/2023

1/4/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

1/4/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

PFNA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

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

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

PFNA Results (μg/Kg)

ND

>ND - 19

>19 - 250

>250 - 2,500

>2,500

AECOM 6-19
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

0 225 450 900

Feet

PFOA Results (ng/L)

ND

>ND - 6

>6 - 40

>40 - 70

>70

PFOA PFOS PFBS

Figure 6-6

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

3/31/2023

3/31/2023

3/31/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

3/31/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

Groundwater Flow Direction

PFOA, PFOS, and PFBS Detections in Groundwater

12420 Milestone Center Drive

Germantown, MD 20876

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

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 6-20
GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

GUL-01

GUL-03 AOI01-01

AOI02-01

GUL-02

AOI04-01

GUL-05

AOI03-01

GUL-04

AOI02-02

AOI02-03

0 225 450 900

Feet

PFHxS Results (ng/L)

ND

>ND - 39

>39 - 100

>100 - 1,000

>1,000

PFHxS PFNA

/ Figure 6-7

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Gulfport AVCRAD, MS

3/31/2023

3/31/2023

3/31/2023

MS

JH

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

3/31/2023

1:5,400

Facility Boundary

River/Stream

Canal/Ditch

Pipeline

Groundwater Flow Direction

PFHxS and PFNA Detections in Groundwater

12420 Milestone Center Drive

Germantown, MD 20876

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

PFNA Results (ng/L)

ND

>ND - 6

>6 - 100

>100 - 1,000

>1,000

AECOM 6-21
6-22

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 7-1

7. Exposure Pathways

The conceptual site models (CSMs) for each AOI, revised based on the SI findings, are presented 

on Figure 7-1 through Figure 7-4. Please note that while the CSM discussion assists in 

determining if a receptor may be impacted, the decision to move from SI to RI or interim action is 

determined based upon exceedances of the SLs for the relevant compounds and whether the 

release is more than likely attributable to the DoD. A CSM presents the current understanding of 

the site conditions with respect to known and suspected sources, potential transport mechanisms 

and migration pathways, and potentially exposed human receptors. A human exposure pathway 

is considered potentially complete when the following conditions are present:

1. Contaminant source;

2. Environmental fate and transport;

3. Exposure point;

4. Exposure route; and

5. Potentially exposed populations.

If any of these elements are missing, the pathway is incomplete. The CSM figures use an empty 

circle symbol to represent an incomplete exposure pathway. Areas with an incomplete pathway 

generally warrant no further action. However, the pathway is considered potentially complete if the 

relevant compounds are detected, in which case the CSM figure uses a half-filled circle symbol to 

represent a potentially complete exposure pathway. Additionally, a completely filled circle symbol is 

used to indicate when a potentially complete exposure pathway has detections of relevant 

compounds above the SLs. Areas with an identified potentially complete pathway that have 

detections of the relevant compounds above the SLs may warrant further investigation. Although 

the CSMs indicate whether potentially complete exposure pathways may exist, the 

recommendation for future study in an RI or no action at this time is based on the comparison of 

the SI analytical results for the relevant compounds to the SLs. 

In general, the potential routes of exposure to the relevant compounds are ingestion and 

inhalation. Human exposure via the dermal contact pathway may occur, and current risk practice 

suggests it is an insignificant pathway compared to ingestion; however, exposure data for dermal 

pathways are sparse and continue to be the subject of toxicological study. The receptors 

evaluated are consistent with those listed in USEPA guidance for risk screening (USEPA, 2001). 

Receptors at the facility include site workers (e.g., facility staff and visiting soldiers), construction 

workers, trespassers (though unlikely due to restricted access), residents outside the facility 

boundary, and recreational users outside of the facility boundary. 

7.1 Soil Exposure Pathway 

The SI results in soil were used to determine whether a potentially complete pathway exists 

between the source and potential receptors at AOI 1, AOI 2, AOI 3, and AOI 4 based on the 

aforementioned criteria. 

7.1.1 AOI 1

A large release of Jet-X at AOI 1 occurred in 2018 during a full test of the fire suppression system. 

The release was drained through the floor drains to the OWS, which discharges to the city sanitary 

sewer system. 
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 7-2

PFOS, PFHxS, and PFNA were detected in surface soil at AOI 1. Site workers, construction 

workers, and trespassers could contact constituents in surface soil via incidental ingestion of soil 

and inhalation of dust. No ongoing construction was observed at the facility. Therefore, the surface 

soil exposure pathways for site workers, future construction workers, and trespassers are 

potentially complete. PFOS, PFHxS and PFNA were detected in subsurface soil at AOI 1. 

Construction workers could contact constituents in subsurface soil during future construction 

activities via incidental ingestion; therefore, the subsurface soil exposure pathway for future 

construction workers is potentially complete. The on-facility golf driving range is located 

approximately 500 feet northwest from AOI 1, while the off-facility golf course is located 

approximately 500 feet to the northeast. Therefore, the on- and off-facility recreational user 

exposure pathway via inhalation of dust is potentially complete. There are no nearby residents to 

AOI 1. Consequently, the exposure pathways for residents are considered incomplete. The CSM

for AOI 1 is presented on Figure 7-1. 

7.1.2 AOI 2

AOI 2 houses a fire suppression system equipped with a 900-gallon AFFF tank, which was 

observed to be stained and corroded on the exterior and throughout the fire suppression system, 

indicating a potential release during the 2018 bladder change. Additionally, hurricane damage to 

the hanger in 2020 resulted in damage to the fire suppression system and caused a release of 

AFFF. The majority of the release was contained to the hangar and was drained through the floor 

drains to the OWS, which discharges to the city sanitary sewer system.

PFOA, PFOS, PFBS, PFHxS, and PFNA were detected in surface soil at AOI 2 and at the 

downgradient facility boundary location GUL-03. Site workers, construction workers, and 

trespassers could contact constituents in surface soil via incidental ingestion of soil and inhalation 

of dust. Therefore, the surface soil exposure pathways for site workers, future construction 

workers, and trespassers are potentially complete. PFOS and PFNA were detected in subsurface 

soil at AOI 2. Construction workers could contact constituents in subsurface soil during future 

construction activities via incidental ingestion; therefore, the subsurface soil exposure pathway 

for future construction workers is potentially complete. The golf course is located approximately 

500 feet to the northeast of AOI 2. Therefore, the off-facility recreational user exposure pathway 

via incidental inhalation of dust is potentially complete for AOI 2. There are no nearby residents 

to AOI 1. Consequently, the exposure pathways for residents are considered incomplete. The 

CSM for AOI 2 is presented on Figure 7-2. 

7.1.3 AOI 3

In the 1990s, nozzle testing with AFFF was conducted by MSANG personnel at AOI 3 and is 

known to have occurred on both sides of the Aircraft Parking Ramp. The AFFF released on the 

Aircraft Parking Ramp may have directly contacted surface soil adjacent to the ramp, entered the 

trench drains on the ramp, or infiltrated the cracks and seams in the ramp directly to the 

subsurface soil or shallow groundwater. The northeast to southwest-trending drain leads to an 

off-facility detention pond and the MSANG Outfall 003.

PFOA, PFOS, PFHxS, and PFNA were detected in surface soil at AOI 3 and at the downgradient 

location GUL-05. PFHxS was detected at side-gradient location GUL-04. Site workers,

construction workers, and trespassers could contact constituents in surface soil via incidental 

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

future construction workers, and trespassers are potentially complete. PFOA, PFOS, PFHxS, and 

PFNA were detected in subsurface soil at AOI 3 and GUL-05. Construction workers could contact 

constituents in subsurface soil during future construction activities via incidental ingestion; 

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

complete. AOI 3 is located more than 800 feet away from off-facility residents and recreational 
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 7-3

users. Therefore, the exposure pathways for these receptors are considered incomplete. The 

CSM for AOI 3 is presented on Figure 7-3.

7.1.4 AOI 4

Tri-MaxTM extinguisher units were historically staged at AOI 4. PFOS and PFHxS were detected in 

surface soil at AOI 4. Site workers, construction workers, and trespassers could contact 

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

surface soil exposure pathways for site workers, future construction workers, and trespassers are 

potentially complete. PFBS and PFOS were detected in subsurface soil at AOI 4. Construction

workers could contact constituents in subsurface soil during future construction activities via 

incidental ingestion; therefore, the subsurface soil exposure pathway for future construction 

workers is potentially complete. There are no nearby off-facility residents and recreational users; 

therefore, the exposure pathways for these receptors are considered incomplete. The CSM for 

AOI 4 is presented on Figure 7-4. 

7.2 Groundwater Exposure Pathway

The SI results in groundwater were used to determine whether a potentially complete pathway 

exists between the source and potential receptors based on the aforementioned criteria.

7.2.1 AOI 1

PFOA, PFOS, PFHxS, and PFNA were detected in groundwater above their SLs at AOI 1. PFOS 

and PFHxS were detected in groundwater above their SLs at the downgradient facility boundary 

location GUL-01. There are multiple downgradient domestic drinking water wells within 4 miles to 

the north of the facility boundary. These wells are generally drilled at depths of 170 to 220 feet 

bgs. Additionally, there are multiple wells of unknown use that are screened at much shallower 

depths (less than 75 feet bgs). Due to the uncertainty of well use, the ingestion exposure pathway 

for off-facility residents is conservatively considered potentially complete. The facility sources its 

drinking water from supply wells within the Graham Ferry aquifer; therefore, the drinking water 

pathway via groundwater to site workers and trespassers is incomplete. At AOI 1, groundwater 

was observed at a depth of 0.88 feet bgs. The construction worker exposure scenario assumes 

excavation occurs at depths at or above 15 feet bgs. Additionally, site workers may encounter 

shallow groundwater at depths above 2 feet bgs. Therefore, the incidental ingestion exposure 

pathway is considered potentially complete for future construction workers and site workers. The 

CSM for AOI 1 is presented on Figure 7-1.

7.2.2 AOI 2

PFOA, PFOS, and PFNA were detected in groundwater above their SLs at AOI 2 and at the 

downgradient facility boundary location GUL-03. There are multiple downgradient domestic 

drinking water wells within 4 miles to the north of the facility boundary screened at depths of 170 

to 220 feet bgs. There are also multiple wells of unknown use screened at depths less than 75 

feet bgs. Due to the uncertainty of well use, the ingestion exposure pathway for off facility 

residents is considered potentially complete. The facility sources its drinking water from supply 

wells within the Graham Ferry aquifer; therefore, the drinking water pathway via groundwater to 

site workers and trespassers is incomplete. At AOI 2, groundwater was observed at depths 

ranging between 1.84 and 5.13 feet bgs. Therefore, the incidental ingestion exposure pathway is 

considered potentially complete for future construction workers and current/future site workers. 

The CSM for AOI 2 is presented on Figure 7-2.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 7-4

7.2.3 AOI 3

PFOA, PFOS, PFHxS, and PFNA were detected in groundwater above their SLs at AOI 3 and at 

the downgradient location GUL-05. There are multiple downgradient domestic drinking water 

wells within 4 miles to the north of the facility boundary screened at depths of 170 to 220 feet bgs.

There are also multiple wells of unknown use screened at depths less than 75 feet bgs. Due to 

the uncertainty of well use, the ingestion exposure pathway for off facility residents is considered 

potentially complete. The facility sources its drinking water from supply wells within the Graham 

Ferry aquifer; therefore, the drinking water pathway via groundwater to site workers and 

trespassers is incomplete. At AOI 2, groundwater was observed at depths ranging between 0.97

and 2.16 feet bgs. Therefore, the incidental ingestion exposure pathway is considered potentially 

complete for future construction workers and current/future site workers. The CSM for AOI 3 is 

presented on Figure 7-3.

7.2.4 AOI 4

PFOA and PFOS were detected in groundwater above their SLs at AOI 4. There are multiple 

downgradient domestic drinking water wells listed within 4 miles to the north of the facility

boundary screened at depths of 170 to 220 feet bgs. There are also multiple wells of unknown 

use screened at depths less than 75 feet bgs. Due to the uncertainty of well use, the ingestion 

exposure pathway for off facility residents is considered potentially complete. The facility sources 

its drinking water from supply wells within the Graham Ferry aquifer; therefore, the drinking water 

pathway via groundwater to site workers and trespassers is incomplete. At AOI 2, groundwater 

was observed at a depth of 3.91 feet bgs. During wet periods, the water level may rise to depths 

shallower than 2 feet bgs. Therefore, the incidental ingestion exposure pathway is considered 

potentially complete for future site workers and future construction workers. The CSM for AOI 4

is presented on Figure 7-4.

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

Releases within the New Paint Hangar were drained via floor drains to the OWS. Any releases 

that potentially escaped the hangar may have flowed via drainage ditches to Outfall 002. 

Therefore, the surface water and sediment exposure pathways for site workers, future 

construction workers, and trespassers via the incidental ingestion exposure pathway are 

potentially complete. PFAS are water soluble and can migrate readily from soil to surface water 

via runoff and leaching. PFOS, PFHxS, and PFNA were detected in soil, and PFOA, PFOS, PFBS, 

PFHxS, and PFNA were detected in groundwater at AOI 1; therefore, it is possible that these 

compounds may have migrated to nearby surface water bodies, such as Bayou Bernard. Bayou

Bernard is not sourced for drinking water but is recreationally used. Therefore, the exposure 

pathway to offsite residents is incomplete and the exposure pathway to recreational users is 

considered potentially complete. The CSM for AOI 1 is presented on Figure 7-1.

7.3.2 AOI 2

Releases within the Main Hangar were drained via floor drains to the OWS. Releases that 

escaped the confines of the hangar may have been conveyed to Outfalls 001 or 002 or the onsite 

pond. Therefore, the surface water and sediment exposure pathways for site workers, future 
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 7-5

construction workers, and trespassers via the incidental ingestion exposure pathway are 

potentially complete. PFOS, PFHxS, and PFNA were detected in soil, and PFOA, PFOS, PFBS, 

PFHxS, and PFNA were detected in groundwater at AOI 2; therefore, it is possible that these 

compounds may have migrated to Bayou Bernard. Therefore, the exposure pathway to offsite 

residents is incomplete, and the exposure pathway to recreational users is considered potentially

complete. The CSM for AOI 2 is presented on Figure 7-2.

7.3.3 AOI 3

Releases on the pavement at AOI 3 would have primarily drained northeastward to the off-facility

MSANG Outfall 003, and then to the off-facility detention pond. Any releases on the grassy areas 

of the facility would have been conveyed to the northwest to Outfall 003, which daylights off the 

facility property. Therefore, the surface water and sediment exposure pathway for future 

construction workers via the incidental ingestion is potentially complete, whereas the exposure 

pathways for site workers and trespassers in exposure pathway are considered incomplete.

PFOA, PFOS, PFHxS, and PFNA were detected in soil, and PFOA, PFOS, PFBS, PFHxS, and 

PFNA were detected in groundwater at AOI 3. Consequently, it is possible that these compounds 

may have migrated to Bayou Bernard. Therefore, the exposure pathway to offsite residents is 

incomplete and the exposure pathway to recreational users is considered potentially complete. 

The CSM for AOI 3 is presented on Figure 7-3.

7.3.4 AOI 4

Releases at AOI 4 would have primarily drained to Outfall 003, which daylights off the facility 

property. Therefore, the surface water and sediment exposure pathway for future construction 

workers via the incidental ingestion is potentially complete, whereas the exposure pathways for 

site workers and trespassers in exposure pathway are considered incomplete. PFOS, PFBS and 

PFHxS were detected in soil, and PFOA, PFOS, PFBS, and PFHxS detected in groundwater at 

AOI 4. Consequently, it is possible that these compounds may have migrated to Bayou Bernard. 

Therefore, the exposure pathway to offsite residents is incomplete and the exposure pathway to 

recreational users is considered potentially complete. The CSM for AOI 4 is presented on 

Figure 7-4.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 7-6

THIS PAGE INTENTIONALLY BLANK
Media

SOURCE PATHWAY RECEPTOR

AOI 1

2018 Release of

Jet-X to New

Paint Hangar

Surface soil

Human

activities

Precipitation/

run-off

Leaching/

infiltration

Airborne soil

particulate

Surface soil

at AOI

Surface

water/

sediment

Subsurface

soil

Shallow

groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

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 Trespasser/Recreational User2

Site

Worker

Construction

Worker3 Resident1

/ / /

/ / / /

/ / / /

/ / / /

LEGEND

Figure 7-1

Conceptual Site Model, AOI 1

Gulfport AVCRAD

Potential

Off-Facility

Source Not

under

Control of

ARNG

Trespasser/

Recreational User2

1. Resident refer to off-site receptors.

2. Recreational Users refer to on- and off-facility

receptors.

3. No current active construction at the facility.

Notes:

/

/

AECOM 7-7 
Media

SOURCE PATHWAY RECEPTOR

AOI 2

Release of AFFF

at Main Hangar

due to Hurricane

Damage

Surface soil

Human

activities

Precipitation/

run-off

Leaching/

infiltration

Airborne soil

particulate

Surface soil

at AOI

Surface

water/

sediment

Subsurface

soil

Shallow

groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

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 Trespasser/Recreational User2

Site

Worker

Construction

Worker3 Resident1

/ / /

/ / / /

/ / / /

/ / / /

LEGEND

Figure 7-2

Conceptual Site Model, AOI 2

Gulfport AVCRAD

Potential

Off-Facility

Source Not

under

Control of

ARNG

Trespasser/

Recreational User2

Notes:

/

/

1. Resident refer to off-site receptors.

2. Recreational Users refer to on- and off-facility

receptors.

3. No current active construction at the facility.

AECOM 7-8
Media

SOURCE PATHWAY RECEPTOR

AOI 3

Nozzle Testing

on Aircraft

Parking Ramp

Surface soil

Human

activities

Precipitation/

run-off

Leaching/

infiltration

Airborne soil

particulate

Surface soil

at AOI

Surface

water/

sediment

Subsurface

soil

Shallow

groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

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 Trespasser/Recreational User2

Site

Worker

Construction

Worker3 Resident1

/ / / /

/ /

/ / / /

/ / / /

LEGEND

Figure 7-3

Conceptual Site Model, AOI 3

Gulfport AVCRAD

Potential

Off-Facility

Source Not

under

Control of

ARNG

Trespasser/

Recreational User2

Notes:

1. Resident refer to off-site receptors.

2. Recreational Users refer to on- and off-facility

receptors.

3. No current active construction at the facility.

/ /

AECOM 7-9
Media

SOURCE PATHWAY RECEPTOR

AOI 4 Historic Staging

of Tri-MaxTM units Surface soil

Human

activities

Precipitation/

run-off

Leaching/

infiltration

Airborne soil

particulate

Surface soil

at AOI

Surface

water/

sediment

Subsurface

soil

Shallow

groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

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 Trespasser/Recreational User2

Site

Worker

Construction

Worker3 Resident1

/ / / /

/ /

/ / / /

/ / / /

LEGEND

Figure 7-4

Conceptual Site Model, AOI 4

Gulfport AVCRAD

Potential

Off-Facility

Source Not

under

Control of

ARNG

Trespasser/

Recreational User2

Notes:

1. Resident refer to off-site receptors.

2. Recreational Users refer to on- and off-facility

receptors.

3. No current active construction at the facility.

/ /

AECOM 7-10
Site Inspection Report

AVCRAD, Gulfport, Mississippi

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 23 to 25 May 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, 2022a), except as previously noted in Section 5.8. 

To fulfill the project DQOs set forth in the approved SI QAPP Addendum (AECOM, 2022a), 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-five (25) soil samples from 13 boring locations; 

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

• Nineteen (19) 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 AOI 1, 

AOI 2, AOI 3, and AOI 4 (see Table 8-1). Based on the CSMs developed and revised in light of 

the SI findings, there is potential for exposure to drinking water receptors from all AOIs from 

sources on the facility resulting from historical DoD activities. 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 PFOA, PFOS, PFHxS, PFNA, and PFBS in soil at 

AOI 1 were below their SLs. 

• PFOA, PFOS, PFHxS, and PFNA in groundwater exceeded their SLs. PFOA 

exceeded the SL of 6 ng/L, at a concentration of 48.2 ng/L at location AOI01-01. 

PFOS exceeded the SL of 4 ng/L, with a maximum concentration of 368 ng/L at 

location AOI01-01. PFHxS exceeded the SL of 39 ng/L, at a concentration of 90.9 

ng/L at location AOI01-01. PFNA exceeded the SL of 6 ng/L, at a concentration of 

22.2 ng/L at location AOI01-01. Based on the results of the SI, further evaluation of 

AOI 1 is warranted in an RI.
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 8-2

• At AOI 2:

• The detected concentrations of PFOA, PFOS, PFHxS, PFNA, and PFBS in soil at 

AOI 2 were below their SLs. 

• PFOA, PFOS, and PFNA in groundwater exceeded their SLs. PFOA exceeded the 

SL of 6 ng/L at all four wells, with a maximum concentration of 59.7 ng/L at AOI02-03. 

PFOS exceeded the SL of 4 ng/L, with a maximum concentration of 41.2 ng/L at 

location AOI02-01. PFNA exceeded the SL of 6 ng/L, at a concentration of 6.15 ng/L 

at location AOI02-01. Based on the results of the SI, further evaluation of AOI 1 is 

warranted in an RI.

• At AOI 3:

• The detected concentrations of PFOA, PFOS, PFHxS, and PFNA in soil at AOI 3

were below their SLs. 

• PFOA, PFOS, PFHxS, and PFNA in groundwater exceeded their SLs. PFOA 

exceeded the SL of 6 ng/L, with a maximum concentration of 97.1 J ng/L at location 

AOI03-01. PFOS exceeded the SL of 4 ng/L, with a maximum concentration of 2,090

ng/L at GUL-05. PFHxS exceeded the SL of 39 ng/L, with a maximum concentration 

of 229 ng/L at location GUL-05. PFNA exceeded the SL of 6 ng/L, with a maximum 

concentration of 99.6 ng/L at location GUL-05. Based on the results of the SI, further 

evaluation of AOI 3 is warranted in an RI.

• At AOI 4: 

• The detected concentrations of PFOS, PFHxS, and PFBS in soil at AOI 4 were below 

their SLs. 

• PFOA and PFOS in groundwater exceeded their SLs. PFOA exceeded the SL of 6 

ng/L, at a concentration of 7.07 ng/L at location AOI04-01. PFOS exceeded the SL 

of 4 ng/L, at a concentration of 7.07 ng/L at location AOI04-01. Based on the results 

of the SI, further evaluation of AOI 3 is warranted in an RI. 

Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA 

(commonly referred to as GenX) was not included as an analyte at the time of this SI. Based on 

the CSM developed during the PA and revised based on SI findings, the presence of HFPO-DA 

is not anticipated at the facility because HFPO-DA is generally not a component of MIL-SPEC 

AFFF and based on its history including distribution limitations that restricted use of GenX, it is 

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

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

Table 8-1 summarizes the SI results for soil and groundwater used to determine if an AOI should 

be considered for further investigation under CERCLA and undergo an RI. 
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 8-3

Table 8-1: Summary of Site Inspection Findings and Recommendations

AOI Potential 

Release Area

Soil –

Source 

Area

Groundwater – 

Source Area

Future 

Action

1 New Paint Hangar Proceed to 

RI 

2 Main Hangar and Tank 

Room

Proceed to 

RI 

3 Mississippi ANG 

Aircraft Parking Ramp

Proceed to 

RI

4 Old Aircraft Staging 

Ramp

Proceed to 

RI 

Notes: ANG = Air National Guard; AOI = Area of Interest; N/A = not applicable; RI = Remedial Investigation

Legend:

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected
Site Inspection Report

AVCRAD, Gulfport, Mississippi

AECOM 8-4

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Site Inspection Report

AVCRAD, Gulfport, Mississippi

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, 1108th Theatre Aviation Sustainment 

Maintenance Group (TASMG), Gulfport, Mississippi. September. 

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

Addendum, Aviation Classification Repair Activity Depot, Gulfport, Mississippi, 

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

ARNG Installations, Nationwide. May. 

AECOM. 2022b. Final Site Safety and Health Plan, Aviation Classification Repair Activity Depot, 

Gulfport, Mississippi, Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid 

(PFOA) Impacted Sites ARNG Installations, Nationwide. May. 

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

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