FINAL 

Site Inspection Report 

Army Aviation Support Facility No. 2 

Tupelo, 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 

May 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 Western Release Areas ................................................................................ 3-1

3.2 AOI 2 Bladder Rupture Release ............................................................................. 3-1

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 Permanent Well Installation and Groundwater Sampling ....................................... 5-3

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

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

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

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

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

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

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

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

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

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

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
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6.4.2 AOI 2 Groundwater Analytical Results ......................................................... 6-4

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

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

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

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

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

7.2 Groundwater Exposure Pathway ............................................................................ 7-2

7.2.1 AOI 1 ............................................................................................................ 7-2

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

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

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

7.3.2 AOI 2 ............................................................................................................ 7-3

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

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

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

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

Appendix A Data Usability Assessment and Validation Reports

Appendix B Field Documentation

B1. Log of Daily Notice of Field Activities

B2. Sampling Forms

B3. Survey Data 

B4. Field Change Request Forms

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, September 2021

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

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, Permanent Well Screen Intervals, and Groundwater 

Elevations

Table 6-1 Screening Levels (Soil and Groundwater)

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

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

Table 6-4 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Deep Subsurface Soil

Table 6-5 PFOA, PFOS, PFBS, PFNA, and PFHxS Results in Groundwater

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

% percent

°C degrees Celsius

°F degrees Fahrenheit

μg/kg micrograms per kilogram

AASF Army Aviation Support Facility

AECOM AECOM Technical Services, Inc.

AFFF aqueous film-forming foam

AOI Area of Interest

ARNG Army National Guard

bgs below ground surface 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CoC chain of custody

CSM conceptual site model 

DA Department of the Army

DoD Department of Defense

DQO data quality objective

DUA data usability assessment

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

FedEx Federal Express

FTA Fire Training Area

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

MDEQ Mississippi Department of Environmental Quality

MIL-SPEC military specification

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

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PID photoionization detector

PQAPP Programmatic UFP-QAPP
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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

USGS United States Geological Survey
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

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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 two 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 Tupelo Army Aviation Support Facility (AASF) #2 in Tupelo, Mississippi and 

determined further evaluation under the Comprehensive Environmental Response, 

Compensation, and Liability Act (CERCLA) is warranted for AOI 1 and AOI 2. The Tupelo AASF 

#2 will also be referred to as the “facility” throughout this document. 

The Tupelo AASF occupies 38.99 acres along West Jackson Street, on the eastern side of Tupelo 

Regional Airport in Tupelo, Mississippi. The mission of the facility is to support operations and use 

of ARNG aviation. The AASF houses multiple guard units and repairs and maintains aircraft. The 

building was designed to be a state emergency mobilization site for the State of Mississippi and 

operates in a dual role as an emergency center and AASF. 

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

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

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

for AOI 1 and AOI 2. 

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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Army Aviation Support Facility No. 2, Tupelo, Mississippi

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

Analyteb

Residential

(Soil)

(μg/kg)a 

0-2 feet bgs

Industrial/ Commercial 

Composite Worker

(Soil)

(μg/kg)a 

2-15 feet bgs

Tap Water

(Groundwater) 

(ng/L)a

PFOA 19 250 6 

PFOS 13 160 4 

PFBS 1,900 25,000 601 

PFHxS 130 1,600 39

PFNA 19 250 6 

Notes:

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

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

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

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

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

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

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

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

AOI

Potential 

Release 

Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater –

Facility 

Boundary

Future Action

1

Western 

Release 

Areas

Proceed to RI 

2

Bladder 

Rupture 

Release

Proceed to RI

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 Tupelo Army 

Aviation Support Facility (AASF) #2 in Tupelo, Mississippi. The Tupelo AASF #2 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 Tupelo AASF #2 (AECOM Technical Services, Inc. [AECOM], 2020) that

identified two 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 

Tupelo AASF #2 is located on the eastern side of Tupelo Regional Airport in Lee County, Tupelo, 

Mississippi (Figure 2-1). AASF #2 is situated approximately 1.5 miles south of McCullough 

Boulevard and 1 mile west of Natchez Trace Parkway. The latitude, longitude, and surface 

elevation at the main gate of the AASF #2 are 34°16’21.6” N; 88°45’52.5” W, and 321 feet above 

mean sea level, respectively. Construction of the current AASF was finished in 2011, and it 

encompasses 38.99 acres. According to leasing documents, the land has been leased to the 

State of Mississippi from the Tupelo Airport Authority since December 2007. The term of the lease 

is 40 years and is set to end on 10 December 2047. Prior to construction of the current facility, 

the Old AASF was operated by the Mississippi ARNG (MSARNG) from the 1960s to 2008 and 

was located at the southern end of the airport, approximately 0.5 miles south of its current location; 

the Old AASF is currently privately owned by an aviation salvage company.

The mission of the facility is to support operations and use of ARNG aviation. AASF #2 houses 

multiple guard units and repairs and maintains aircraft. The building was designed to be a state 

emergency mobilization site for the State of Mississippi and operates in a dual role as an 

emergency center and AASF. 

2.2 Facility Environmental Setting

Tupelo is in the Black Belt Prairie physiographic region, which is a crescent-shaped region 

approximately 25 miles wide that stretches from Alabama, through northeastern Mississippi, into 

southern Tennessee. The topography of the facility generally slopes to the east and north as 

shown on Figure 2-2. The Black Belt Prairie is characterized by its dark, fertile soil used primarily 

for farmland, and it is underlain by Cretaceous-aged geologic units (National Aeronautics and 

Space Administration, 2018). The facility sits at an elevation of about 330 to 350 feet above mean 

sea level. 

2.2.1 Geology

Tupelo is situated on top of the Cretaceous-aged Selma Group, with locally overlying yellowishorange alluvium deposits composed primarily of clay, silt, and sand. The Selma Group has three 

members: the Demopolis Chalk, the Coffee Sand, and the Mooreville Chalk. In the eastern section 

of the Tupelo 7.5-minute Quadrangle, Coffee Sand outcrops are present. In the western section, 

closer to the AASF, Demopolis Chalk outcrops are present (Mississippi Department of 

Environmental Quality [MDEQ], 2019a). 

As shown on Figure 2-3, AASF #2 is situated 1 mile west of the Coffee-Demopolis contact. The 

contact at this point is mapped at a ground surface elevation of approximately 300 feet. Bedrock 

in this area dips west about 30 feet per mile (Mississippi State Geological Survey, 1962) and the 

ground surface elevation of AASF #2 ranges from about 330 to 315 feet; the top of the Coffee 

Sand underlying AASF #2 may be encountered at a depth as shallow as 45 feet below ground 

surface (bgs).

The Selma Group overlies the Eutaw and Tuscaloosa formations. Mineral resources in Lee 

County include limestone, water, and rocks with sufficient calcium and aluminum silicates to 

manufacture mineral wool (Mississippi State Geological Survey, 1946).

Soil borings completed during the SI found silty clay and sandy clay as the dominant lithology of 

the unconsolidated sediments below the AASF #2. The borings were completed at depths 
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between 15.5 and 40 feet bgs. Isolated layers of sand to silty sand were also observed in the 

boring logs, at thicknesses ranging from 1.5 to 3.5 feet. Many of the logs also reported varying 

percentages of chalk fragments included in the sand packages before encountering the 

underlying chalk. Samples for grain size analyses were collected at two locations, AOI01-01 (from 

16.5-18.5 feet bgs) and AOI02-02 (from 38-40 feet bgs), and were analyzed via American Society 

for Testing and Materials Method D-422. The results indicate that the soil samples are comprised 

primarily of silt (57.12 percent [%] to 59.3%) and clay (29.86% to 34.89%). These facility 

observations are consistent with the understood depositional environment. Boring logs are 

presented in Appendix E, and grain size results are presented in Appendix F. 

2.2.2 Hydrogeology

AASF #2 sits atop the Coffee Sand, Eutaw-McShan, and Gordo (part of the Tuscaloosa formation) 

aquifers and may also overly the Paleozoic aquifer, although its lateral extent is not fully known 

(MDEQ, 2014; Strom and Mallory, 1995). The Paleozoic aquifer system consists of chert beds, 

sandstone, shale, and limestone, whereas the Gordo, Eutaw-McShan, and Coffee Sand aquifers 

consist mostly of clay, sand, and, in the case of the Coffee Sand aquifer, sandstone (O’Hara, 

1996). 

The Eutaw-McShan aquifer is confined by the Mooreville Chalk, which ranges in thickness from 

approximately 115 to 160 feet (MDEQ, 2019a). Various sources disagree with the latitude at which 

the Mooreville Chalk becomes absent. Boswell states that the Mooreville Chalk is absent at 

Tupelo and to the north of the city, meaning that the Coffee Sand and Eutaw-McShan aquifers 

are hydraulically connected (Boswell, 1976). However, Strom and Mallory state that the 

disappearance of the Mooreville Chalk occurs at a latitude close to the Union-Pontotoc county 

boundary, meaning the Eutaw-McShan aquifer is confined at Tupelo (Strom and Mallory, 1995). 

Additionally, the Tupelo 7.5-minute quadrangle map identified the Mooreville Chalk in Tupelo 

(MDEQ, 2019a), further suggesting the Eutaw-McShan is confined at the facility.

The 2014 MDEQ groundwater assessment surveyed a few wells within Lee County that were 

tapping into the Coffee Sand, Eutaw-McShan, and Gordo aquifers. The surveyed wells that collect 

water in the Coffee Sands aquifer were 147 and 200 feet bgs, 606 feet bgs in the Eutaw-McShan 

aquifer, and 669 feet bgs in the Gordo aquifer. 

No potable water wells are located within facility boundaries. Drinking water at AASF #2 and the

local area is supplied by the City of Tupelo, which purchases drinking water from the Northeast 

Mississippi Regional Water District, who obtains the water from the Tombigbee River, 

approximately 18 miles east of the facility. However, a domestic well exists approximately 400 feet 

east of the facility boundary (Figure 2-3) and is completed within the Eutaw-McShan aquifer at 

550 feet bgs. The US Geological Survey (USGS) National Ground Water Information System and 

the MDEQ Borehole Collection provide borehole data for wells around Tupelo (USGS, 2019; 

MDEQ, 2019b). No wells downgradient of AASF #2 that collect water at depths less than 400 feet 

bgs have been identified, suggesting that none of the identified wells are collecting water in the 

Coffee Sand aquifer. Based on the research presented above, these wells should be screened 

within the Eutaw-McShan aquifer.

Depths to water measured in September 2021 during the SI ranged from 4.94 to 11.29 feet bgs. 

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

groundwater flow direction is generally to the east. 

2.2.3 Hydrology

AASF #2 is situated within the eastern portion of Kings Creek-Town Creek Watershed; the Little 

Coonewah Creek-Coonewah Creek watershed is present to the west of the facility and bisects 

the Tupelo Regional Airport (Figure 2-5). Local surface water features include small, unnamed 
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ponds and tributaries that flow into Kings Creek. A drainage ditch associated with one of the 

unnamed tributaries runs along the eastern facility boundary and flows north. Stormwater at AASF 

#2 is directed towards one of two retention ponds located within the northeastern portion of the 

facility. These retention ponds overflow into the drainage ditch system that flows north before 

joining Kings Creek to the northeast and ultimately flows southeast through the City of Tupelo. 

2.2.4 Climate

The humid subtropical climate at Tupelo AASF #2 is characterized as having long, hot summers, 

and a relatively short, mild winter (Mississippi State Geological Survey, 1946). The average 

temperature is 73.4 degrees Fahrenheit (°F). Seasonally, temperatures vary from a summer 

average monthly high of 92 °F to a winter average monthly low of 32 °F. Average precipitation is 

55 inches (World Climate, 2022). 

2.2.5 Current and Future Land Use

AASF #2 is a controlled access facility and is located adjacent to the Tupelo Regional Airport. The 

Tupelo Regional Airport is owned and operated by the Tupelo Airport Authority. AASF #2 operates 

in a dual role as a state emergency center and AASF. Reasonably anticipated future land use is 

not expected to change from the current land use. 

2.2.6 Sensitive Habitat and Threatened/ Endangered Species 

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

threatened, proposed, and/ or are listed as candidate species in Lee County, Mississippi (US Fish 

and Wildlife Service [USFWS], 2022). 

• Insects: Monarch butterfly, Danaus plexippus (candidate)

• Birds: Wood stork, Mycteria americana (threatened)

• Flowering plants: Prices potato-bean, Apios priceana (threatened)

• Mammals: Northern long-eared bat, Myotis septentrionalis (threatened)

• Reptiles: Alligator snapping turtle, Macrochelys temminckii (proposed threatened)

2.3 History of PFAS Use 

Five potential release areas identified at the facility during the PA were grouped into two AOIs 

based on proximity to one another as well as groundwater flow direction (AECOM, 2020). AASF 

#2 includes one building that serves a dual role as an emergency center and AASF. The hangar 

is equipped with fire suppression systems that utilize AFFF. At the facility, there have been

documented releases from the fire suppression system by way of testing and system malfunction, 

and AFFF may also have been released at the facility during fire training activities. Descriptions 

of AOI 1 and AOI 2 are presented in Section 3. 
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Site Inspection at Tupelo AASF, MS

1:63,360

8/15/2022 ­ Figure 2-1 PM CM 8/15/2022

12420 Milestone Center Drive

Germantown, MD 20876

Facility Location

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

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

^_

Tupelo AASF

PROJECT

0 0.5 1 2

Miles

Legend

Facility Boundary

Tupelo Regional Airport

AECOM 2-5 
330

320

340

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

JH

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8/15/2022

Site Inspection at Tupelo AASF, MS

1:6,000

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12420 Milestone Center Drive

Germantown, MD 20876

Facility Topography

Base Map: USGS The National Map: National

Boundaries Dataset, 3DEP Elevation Program,

PROJECT

0 250 500 1,000

Feet

Legend

Facility Boundary

AECOM 2-6
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SCALE

9/9/2022 MS

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ARNG

GIS BY

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Site Inspection at Tupelo AASF, MS

PM CM 9/9/2022

1:95,040 ­ 12420 Milestone Center Drive

Germantown, MD 20876

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

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AECOM 2-7
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Site Inspection at Tupelo AASF, MS

10/20/2022

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Site Inspection at Tupelo AASF, MS

PM CM 9/9/2022

1:31,680 ­ 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

AECOM 2-9
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 2-10

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Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, 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 Tupelo AASF #2 and grouped into two AOIs (AECOM, 2020). The potential release 

areas are shown on Figure 3-1. Additional, adjacent potential release areas identified at the 

Tupelo Regional Airport and Old AASF Property and Hangar are also shown on Figure 3-1 for 

informational purposes and will not be evaluated as part of this SI. 

3.1 AOI 1 Western Release Areas

AOI 1 Western Release Areas encompasses Release Areas A, B, C, and E. During a training 

event, an unknown quantity of AFFF was discharged into the wash rack (Release Area A), which 

discharges to the oil/water separator (OWS) and, subsequently, the sanitary sewer. Additionally, 

during an initial test of the hangar suppression system, an unknown quantity of AFFF was pumped 

out and directed towards the trench drain at the hangar bay doors. The trench drain flows to the 

OWS; however, in the event of activation of the fire suppression system, a trigger lock bypasses 

the OWS, and the trench drains are discharged to a retention pond in the northern area of the 

facility. In this event, a manual valve on the retention pond is supposed to be closed in order to 

prevent the AFFF and water from leaving the property until the release can be cleaned up. Facility 

staff interviewed during the PA did not know if either the trigger lock or manual valve were 

activated during testing. Therefore, it is unknown if test water entered the OWS or were 

discharged directly to the retention pond. Foam may have also been discharged to stormwater 

drains on the apron during testing (collectively Release Area B). As a result, an unknown quantity 

of AFFF may have flowed directly into a retention pond to the north of AOI 1 (Release Area C) 

from either of these drains during testing. Lastly, out-of-date AFFF was stored in a hazardous 

waste storage area (Release Area E), although no spills or leaks were reported.

Although no permanent surface water bodies are present within AOI 1, facility stormwater flows 

into this retention pond (Release Area C) via a system of stormwater drains. Additionally, the 

retention pond receives drainage from the hangar whenever the fire suppression system is 

activated. The retention pond drains into an unnamed tributary of Kings Creek; therefore, both 

release events may have potentially impacted surface water, sediment, and surface soil at 

Release Area C. Potential releases may have migrated from surface soil to subsurface soil and 

groundwater via leaching.

3.2 AOI 2 Bladder Rupture Release

AOI 2 encompasses Release Area D and is located east of AOI 1. Due to a hardware malfunction 

from tank installation, approximately 800-gallons of AFFF were discharged inside the AASF 

building. The AFFF subsequently flowed out of the building, into the parking lot to the east, filled 

the eastern drainage ditches and retention pond, and eventually flowed out onto W Jackson 

Street; the foam was allowed to naturally dissipate.

The eastern drainage ditch and retention pond discharge into the same unnamed tributary as 

Release Area C in AOI 1. Consequently, there may have been a release to surface water, 

sediment, and surface soil. Additionally, foam that dissipated on the parking lot and W Jackson 

Street was likely transported by overland flow to surface soils and/or sediment. Depending on 

infiltration rates, potential releases may migrate from the surface soil to subsurface soil and 

groundwater via leaching and also infiltrate from the pond to groundwater. 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 3-2

THIS PAGE INTENTIONALLY BLANK
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Site Inspection at Tupelo AASF, MS

2/3/2023

2/3/2023

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

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12420 Milestone Center Drive

Germantown, MD 20876

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AECOM 3-3
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 3-4

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Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 4-1

4. Project Data Quality Objectives

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

Assurance Project Plan (QAPP) Addendum (AECOM, 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 Tupelo AASF #2 (AECOM, 2020);

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

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

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

parameters measured at the time of sampling.

4.3 Study Boundaries

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

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

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

owner(s). Temporal boundaries were limited to the summer season, which was the earliest available 

time that field resources were available to complete the study.

4.4 Analytical Approach

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

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

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

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

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

4.5 Data Usability Assessment 

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

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

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

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

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

whether the collected data are of the right type, quality, and quantity to support the decisionmaking (DoD, 2019a; DoD, 2019b; USEPA, 2017). 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 4-2

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

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

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

requirements of the SI QAPP Addendum (AECOM, 2021a). 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 5-1

5. Site Inspection Activities

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

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

in accordance with the following approved documents: 

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

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

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

• Final Preliminary Assessment Report, Tupelo Army Aviation Support Facility No. 2, Tupelo, 

Mississippi dated July 2020 (AECOM, 2020); 

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

Tupelo Army Aviation Support Facility No. 2, Tupelo, Mississippi dated August 2021

(AECOM, 2021a); and

• Final Site Safety and Health Plan, Tupelo Army Aviation Support Facility No. 2, Tupelo, 

Mississippi dated August 2021 (AECOM, 2021b). 

The SI field activities were conducted from 27 August to 8 September 2021 and consisted of utility 

clearance, sonic boring, soil sample collection, permanent monitoring well installation, 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-three (23) soil samples from 13 boring locations; 

• Four groundwater samples from four permanent monitoring wells; 

• Sixteen (16) quality assurance (QA)/quality control (QC) samples.

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

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

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

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

Appendix B3, and a Field Change Request form is provided in Appendix B4. Additionally, a 

photographic log of field activities is provided in Appendix C. 

5.1 Pre-Investigation Activities

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

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

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

5.1.1 Technical Project Planning

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

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

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

collection plan. The process encourages stakeholder involvement in the SI, beginning with 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 5-2

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

address the AOIs identified in the PA. 

A combined TPP Meeting 1 and 2 was held on 8 March 2021, prior to SI field activities. The 

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

stakeholders for this SI include the ARNG, MSARNG, USACE, 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, 2021a). 

A TPP Meeting 3 was held on 7 March 2023 to discuss the results of the SI. Meeting minutes for 

TPP 3 are included in Appendix D of this report. Future TPP meetings will provide an opportunity 

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

5.1.2 Utility Clearance

AECOM’s drilling subcontractor, Cascade Technical Services, LLC. placed a ticket with the 

Mississippi 811 utility clearance provider to notify them of intrusive work on 23 August 2021. 

However, because the AASF is a private facility, the participating “Call Before You Dig” locators 

did not clear utilities at the entire facility. Therefore, 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 27 August 2021 with input from 

the AECOM field team and Tupelo AASF facility staff. General locating services and groundpenetrating 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 the shallow subsurface where 

utilities would typically be encountered. 

5.1.3 Source Water and Sampling Equipment Acceptability

The potable water source used for decontamination of drilling equipment was confirmed to be 

acceptable for use in this investigation. A sample from a potable water source at Tupelo AASF 

was collected on 16 July 2021, prior to mobilization, and analyzed for LC/MS/MS compliant with 

QSM 5.3 Table B-15. The results of the decontamination water sample are provided in 

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

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

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

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

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

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

member regarding the allowable materials within the sampling environment. 

5.2 Soil Borings and Soil Sampling

Soil samples were collected via sonic methods, in accordance with the SI QAPP Addendum 

(AECOM, 2021a). A GeoProbe® 8140LC was used to collect continuous soil cores to the target 

depth. A hand auger was used to collect soil from the top five feet of the boring, in accordance 

with AECOM utility clearance procedures. The soil boring locations are shown on Figure 5-1 and 

depths are provided Table 5-2. In general, soil samples were collected for chemical analysis from 

the vadose zone of each boring drilled using the sonic rig, specifically three soil samples: one 

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

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

groundwater table. Additionally, one surface soil sample was collected from each of the eight 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 5-3

surface soil borings, which were advanced using a hand auger to depths ranging from 0.5 to 2 

feet bgs.

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

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

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

Observations and measurements were recorded on sampling forms (Appendix B2) and in a nontreated field logbook (i.e., composition notebook). Depth interval, recovery thickness, PID 

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

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

Soil borings completed during the SI found silty and sandy clay as the dominant lithology of the 

unconsolidated sediments below the AASF #2. The borings were completed at depths between 

15.5 and 40 feet bgs. Isolated layers of sand and silty sand were also observed in the boring logs 

at thicknesses ranging from 1 to 3.5 feet. These facility observations are consistent with the 

understood depositional environment. 

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, 2021a).

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

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

same parameters as the accompanying samples. 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.

Sonic borings were converted to permanent monitoring wells in accordance with the SI QAPP 

Addendum (AECOM, 2021a), with the exception of AOI02-02 (see Section 5.8 for more details). 

Borings were installed with a flush mount surface completion in grass areas to avoid disturbing 

concrete or asphalt surfaces.

5.3 Permanent Well Installation and Groundwater Sampling

During the SI, two permanent monitoring wells were installed within the potential source areas, 

and two permanent monitoring wells were installed upgradient and side-gradient of the potential 

source areas. The locations of the wells are shown on Figure 5-1. 

A GeoProbe® 8140LC drill rig was used to install four (4) 2-inch diameter monitoring wells. The 

monitoring wells were constructed with Schedule 40 poly-vinyl chloride (PVC), flush threaded 10-

foot sections of riser, 0.010-inch slotted well screen, and a threaded bottom cap. A filter pack of 

20/40 silica sand was installed in the annulus around the well screen to a minimum of 2 feet above 

the well screen.

A 2-foot-thick bentonite seal was placed above the filter sand and hydrated with distilled water. 

Bentonite grout was placed in the well annulus from the top of the bentonite seal to ground 

surface. The bentonite grout was allowed to set for 24 hours prior to well completion in accordance 

with the SI QAPP Addendum (AECOM, 2021a). All monitoring wells were completed with flush 

mount well vaults. The screen intervals of each of the groundwater monitoring wells are provided 

in Table 5-2. 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 5-4

Development and sampling of wells was completed in accordance with the SI QAPP Addendum 

(AECOM, 2021a). The newly installed monitoring wells were developed no sooner than 24 hours 

following installation by pumping and surging using a variable speed submersible pump. Samples 

were collected no sooner than 24 hours following development via low-flow sampling methods 

using a GeoTech® peristaltic pump with disposable PFAS-free, HDPE tubing. New tubing was 

used at each well. The wells were purged at a rate determined in the field to reduce draw down 

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

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

and recorded on the field sampling form (Appendix B2). Water levels were measured to the 

nearest 0.01 inch and recorded. 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 for LC/MS/MS compliant with QSM 5.3 

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

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

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

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

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

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

5.4 Synoptic Water Level Measurements

A synoptic groundwater gauging event was performed on 8 September 2021. Groundwater 

elevation measurements were collected from the four new permanent monitoring wells. Water 

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

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

5.5 Surveying 

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

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

Survey data from the newly installed wells on the facility were collected on 8 September 2021 in 

the applicable Universal Transverse Mercator zone projection with World Geodetic System 84 

datum (horizontal) and North American Vertical Datum 1988 (vertical). The surveyed well data are 

provided in Appendix B3.

5.6 Investigation-Derived Waste 

As of the date of this report, the disposal of 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, 2021a) and with the DA Guidance for 

Addressing Releases of PFAS, Q18 (DA, 2018). 

Soil IDW (i.e., soil cuttings) generated during the SI activities were containerized in three 55-

gallon drums and staged at the Wash Rack. ARNG will coordinate waste profiling, transportation, 

and disposal of the solid IDW under a separate contract. 

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

decontamination fluids) were containerized in seven 55-gallon drums totaling approximately 303 

gallons and staged at the Wash Rack. The containerized liquid IDW will be characterized,
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 5-5

managed, and disposed of by ARNG (either by offsite disposal or onsite disposal, with treatment 

as appropriate) under a separate contract in accordance with SOP No. 042A for Treating Liquid 

Investigation-Derived Material (Purge water, drilling water, and decontamination fluids) (EA 

Engineering, Science, and Technology, Inc., 2021). 

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

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

activities were disposed of at a licensed solid waste landfill via the AASF #2 waste disposal. 

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

One deviation from the SI QAPP Addendum is noted below. The change is documented in a Field 

Change Request Form (Appendix B4).

• During the installation of permanent monitoring wells, one boring (AOI02-02) was 

advanced up to 40 feet bgs without encountering groundwater. The borehole was 

allowed to remain open overnight to evaluate potential groundwater recharge into the 

borehole; however, dry conditions persisted. This location was at a similar ground 

surface elevation as the other soil borings, but sandy, water-bearing layers encountered 

in other borings were not observed in AOI02-02. Three subsurface soil samples were 

collected at AOI02-02 (0-2, 13-15, and 38-40 feet bgs). Because groundwater was not 

observed at AOI02-02, no groundwater sample was collected, and a permanent well 

was not installed at this location. 
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 5-6

THIS PAGE INTENTIONALLY BLANK
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Tupelo AASF #2, Mississippi

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

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

Comments

AOI01-01-SB-00-02 8/31/2021 1203 0-2 X X X

AOI01-01-SB-00-02-D 8/31/2021 1203 0-2 X FD

AOI01-01-SB-00-02-MS 8/31/2021 1203 0-2 X X MS

AOI01-01-SB-00-02-MSD 8/31/2021 1203 0-2 X X MSD

AOI01-01-SB-06-08 8/31/2021 1240 6-8 X

AOI01-01-SB-11-13 8/31/2021 1340 11-13 X

AOI01-01-SB-16.5-18.5 8/31/2021 1510 16.5-18.5 X

AOI01-02-SS-00-02 8/31/2021 1615 0-2 X

AOI01-03-SS-00-0.5 8/31/2021 1510 0-0.5 X

AOI01-04-SS-00-01 8/31/2021 1650 0-1 X

AOI02-01-SB-00-02 9/2/2021 1120 0-2 X

AOI02-01-SB-00-02-D 9/2/2021 1120 0-2 X FD

AOI02-01-SB-5.25-7.25 9/2/2021 1155 5.25-7.25 X

AOI02-01-SB-9.5-11.5 9/2/2021 1205 9.5-11.5 X

AOI02-02-SB-00-02 9/1/2021 1135 0-2 X X X

AOI02-02-SB-00-02-D 9/1/2021 1135 0-2 X X X FD

AOI02-02-SB-13-15 9/1/2021 1355 13-15 X

AOI02-02-SB-38-40 9/1/2021 1620 38-40 X X

AOI02-03-SS-00-02 9/1/2021 1545 0-2 X

AOI02-04-SS-00-02 9/1/2021 1345 0-2 X

AOI02-05-SS-00-02 9/1/2021 1620 0-2 X

AOI02-06-SS-00-02 9/1/2021 1430 0-2 X

AOI02-07-SS-00-01 9/1/2021 1510 0-1 X

TUP-01-SB-00-02 8/30/2021 1048 0-2 X X X

TUP-01-SB-00-02-MS 8/30/2021 1048 0-2 X MS

TUP-01-SB-00-02-MSD 8/30/2021 1048 0-2 X MSD

TUP-01-SB-02-04 8/30/2021 1053 2-4 X

TUP-01-SB-07-09 8/30/2021 1105 7-9 X

TUP-02-SB-00-02 9/1/2021 0845 0-2 X

TUP-02-SB-00-02-MS 9/1/2021 0845 0-2 X MS

TUP-02-SB-00-02-MSD 9/1/2021 0845 0-2 X MSD

TUP-02-SB-3.5-5.5 9/1/2021 0900 3.5-5.5 X

TUP-02-SB-06-08 9/1/2021 0910 6-8 X

AOI01-01-GW 9/3/2021 1040 NA x

AOI02-01-GW 9/8/2021 1255 NA x

TUP-01-GW 9/2/2021 1535 NA x

TUP-01-GW-D 9/2/2021 1535 NA x FD

TUP-01-GW-MS 9/2/2021 1535 NA x MS

TUP-01-GW-MSD 9/2/2021 1535 NA x MSD

TUP-02-GW 9/3/2021 0915 NA x

Soil Samples

Groundwater Samples

AECOM 5-7
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Tupelo AASF #2, Mississippi

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

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

Comments

TUP-FRB-01 8/30/2021 1300 NA x

TUP-ERB-01 8/31/2021 1150 NA x Hand Auger

TUP-ERB-02 8/31/2021 1200 NA x DPT Drill Shoe

TUP-ERB-03 9/2/2021 0715 NA x

Well 

Development 

Pump

TUP-PW-01 7/16/2021 1458 NA x

TUP-PW-02 9/2/2021 1045 NA x Pressure Washer

Notes:

AASF = Army Aviation Support Facility

AOI = area of interest

ASTM = American Society for Testing and Materials

bgs = below ground surface

DPT = direct push technology

ERB = equipment rinsate blank

FD = field duplicate

FRB = field reagent blank

GW = groundwater

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MS/MSD = matrix spike/ matrix spike duplicate

QSM = Quality Systems Manual

SB = soil boring

SS = surface soil

TOC = total organic carbon

USEPA = United States Environmental Protection Agency

Quality Control Samples

AECOM 5-8
Table 5-2

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

Site Inspection Report, Tupelo AASF #2, Mississippi

Area of 

Interest

Boring 

Location

Soil Boring 

Depth 

(feet bgs)

Permanent 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 AOI01-01 18.5 8.25 - 18.25 2 330.14 330.21 11.22 11.29 318.92

AOI02-01 15.5 5.5 - 15.5 317.99 318.20 4.73 4.94 313.26

AOI02-021 40 NA NA NA NA NA NA

TUP-01 37.5 4 - 14 2 334.1 334.19 7.7 7.79 326.40

TUP-02 15.5 5.5 - 15.5 330.52 330.69 10.78 10.95 319.74

Notes:

1

Groundwater was not encountered and no temporary well was installed.

2

Permanent well screen set above total depth to capture groundwater interface.

AASF = Army Aviation Support Facility

AOI = area of interest

bgs = below ground surface

btoc = below top of casing

NAVD88 = North American Vertical Datum 1988

Facilitywide

2

AECOM 5-9
AECOM 5-10

Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

THIS PAGE INTENTIONALLY BLANK
A!

A!

A!

A!

"J

"J

"J

"J

"J "J

"J

"J

?!

W Jackson Street Ext

AOI02-02

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI01-02

AOI01-03

AOI01-04

AOI02-03

AOI02-04

AOI02-05

AOI02-06

AOI02-07

AOI 1

AOI 2

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

SS

9/9/2022

9/9/2022

Site Inspection at Tupelo AASF, MS

9/9/2022

1:3,000 ­ Figure 5-1 PM CM 9/9/2022

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

Legend

A! Monitoring Well

?! Soil Boring

"J Suface Soil Sample

Area of Interest

Facility Boundary

Surface Water Flow Direction

Groundwater Flow Direction

0 125 250 500

Feet

AECOM 5-11
AECOM 5-12

Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, 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 and

Section 6.4. 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

Army Aviation Support Facility No. 2, Tupelo, 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: Western Release Areas. 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

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 AOI01-01 through 

AOI01-04. Soil was also sampled from shallow subsurface soil (6 to 8 feet bgs and 11 to 13 feet 

bgs) from boring location AOI01-01. No samples were collected from the deep subsurface soil 

(i.e., deeper than 15 feet bgs) at AOI 1. PFOA, PFOS, and PFNA were detected in surface soil at 

concentrations below their respective SLs. PFOA was detected at three of the four locations, with 

concentrations ranging from 0.113 J micrograms per kilogram (μg/kg) to 6.68 μg/kg. PFOS was 

only detected AOI01-03, with a concentration of 0.108 J μg/kg. PFNA was detected at three of 

four boring locations, with concentrations ranging from 0.069 J μg/kg to 9.18 μg/kg. The maximum 

concentrations for PFOA, PFOS, and PFNA in surface soil were detected at boring AOI01-03, 

which was located at the western end of Release Area E. PFHxS and PFBS were not detected in 

surface soil at AOI 1. PFOA, PFOS, PFHxS, PFBS, and PFNA were not detected in either of the 

shallow subsurface soil samples collected at boring AOI01-01. 

Soil samples were also collected from the upgradient facility boundary location TUP-01 and from 

the side-gradient location TUP-02. Soil from these two borings were collected from the surface (0 

to 2 feet bgs) and shallow subsurface (between 2 and 9 feet bgs) intervals. PFOA, PFOS, PFHxS, 

PFNA, and PFBS were not detected at either boring in the surface soil or shallow subsurface soil 

samples. 

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 permanent monitoring well AOI01-01. PFOA was detected above 

the SL of 6 nanograms per liter (ng/L), with a concentration of 7.75 ng/L. PFHxS was detected 
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 6-3

below the SL of 39 ng/L, with a concentration of 1.29 J ng/L. PFBS was detected below the SL of 

601 ng/L, with a concentration of 3.82 J ng/L. PFOS and PFNA were not detected in groundwater 

at AOI 1.

Groundwater was also sampled from the upgradient facility boundary monitoring well TUP-01 and 

the from the side-gradient location TUP-02. At the upgradient TUP-01, PFHxS was detected 

above the SL of 39 ng/L, with a concentration of 43.1 ng/L. PFOA, PFOS, and PFBS were 

detected and did not exceed their SLs at TUP-01, with concentrations of 2.61 J ng/L, 4.00 ng/L,

and 11.7 ng/L, respectively. PFNA was not detected at TUP-01. At the side-gradient location TUP02, PFOA and PFBS were detected below their SLs, with concentrations of 1.19 J ng/L and 1.39 

J ng/L, respectively. PFOS, PFHxS, and PFNA were not detected at TUP-02. 

6.3.3 AOI 1 Conclusions

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

respective SLs. PFOA was detected in groundwater at a concentration above the SL. Additionally, 

PFHxS was detected in groundwater above the SL at monitoring well TUP-01, which is located at 

the western facility boundary and upgradient of AOI 1. Based on the exceedance of the PFOA SL 

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: Bladder Rupture Release. 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

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 AOI02-01 through

AOI02-07. Soil was also sampled from shallow subsurface soil (5.25 to 7.25 feet bgs and 9.5 to 

11.5 feet bgs) at AOI02-01. AOI02-02 was additionally sampled for shallow subsurface soil (13 to 

15 feet bgs) and deep subsurface soil (38 to 40 feet bgs). PFOA, PFOS, and PFNA were detected 

in surface soil, at concentrations below their respective SLs. PFOA was detected in two of seven 

borings, with concentrations of 0.108 J μg/kg at AOI02-02 and 0.144 J μg/kg at AOI02-05. PFOS 

was detected six of seven borings, with detected concentrations ranging from 0.074 J μg/kg to 

0.181 J μg/kg. PFNA was detected in five of seven borings, with concentrations ranging from 

0.029 J μg/kg to 0.069 J μg/kg. The maximum concentrations of PFOS and PFNA in surface soil 

were observed at AOI02-07. PFHxS and PFBS were not detected in the surface soil at any of the 

seven borings. 

PFOA, PFOS, PFHxS, PFBS, and PFNA were not detected in the shallow subsurface soil 

samples collected at AOI 2. Similarly, PFOA, PFOS, PFHxS, PFBS, and PFNA were not detected 

in the deep subsurface soil sample at AOI02-02.

As discussed in Section 6.3.1, soil was also collected from the upgradient facility boundary 

location TUP-01. Soil was collected from the surface (0 to 2 feet bgs) and shallow subsurface (2 

to 4 feet bgs and 7 to 9 feet bgs) intervals. PFOA, PFOS, PFHxS, PFNA, and PFBS were not 

detected in either the surface soil or shallow subsurface soil samples. 
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 6-4

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 permanent monitoring well AOI02-01. PFOA was detected above 

the SL of 6 ng/L, with a concentration of 68.4 ng/L. PFNA was detected above the SL of 6 ng/L, 

with a concentration of 11.7 ng/L. PFOS, PFHxS, and PFBS were detected below their SLs, with 

concentrations of 1.61 J ng/L, 9.11 ng/L, and 3.11 J ng/L, respectively.

As discussed in Section 6.3.2, groundwater was also sampled from the upgradient facility 

boundary monitoring well TUP-01. At the upgradient TUP-01, PFHxS exceeded the SL of 39 ng/L, 

with a concentration of 43.1 ng/L. PFOA, PFOS, and PFBS were detected and did not exceed 

their SLs at TUP-01, with concentrations of 2.61 J ng/L, 4.00 ng/L, and 11.7 ng/L, respectively. 

PFNA was not detected at TUP-01. 

6.4.3 AOI 2 Conclusions

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

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

PFHxS was detected above the SL in groundwater at monitoring well TUP-01, which is located at 

the western facility boundary and upgradient of AOI 2. Based on the exceedances of the SLs in 

groundwater, further evaluation at AOI 2 is warranted. 
Table 6-2

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

Site Inspection Report, Tupelo AASF #2

Analyte OSD Screening 

Level a

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

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

PFHxS 130 ND U ND U ND U ND U ND U ND U ND U ND U ND U ND U

PFNA 19 ND U ND U 0.180 J 9.18 0.069 J ND U ND U 0.034 J 0.046 J 0.056 J

PFOA 19 ND U ND U 0.842 J 6.68 0.113 J ND U ND U 0.108 J ND UJ ND U

PFOS 13 ND U ND U ND U 0.108 J ND U ND UJ 0.074 J 0.087 J 0.111 J 0.126 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

Acronyms and Abbreviations

AASF Army Aviation Support Facility

AOI Area of Interest

D duplicate

DL detection limit

ft feet

HQ hazard quotient

ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

ND analyte not detected above the LOD

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

PFNA: 0.058-0.073 μg/kg Qual interpreted qualifier

PFOA: 0.231-0.292 μg/kg SB soil boring

PFOS: 0.231-0.292 μg/kg SS surface soil

TUP Tupelo

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

Area of Interest

Sample ID

Sample Date

Depth

AOI01-01-SB-00-02

08/31/2021

0-2 ft

AOI01-01-SB-00-02-D

08/31/2021

0-2 ft

AOI01-02-SS-00-02

08/31/2021

0-2 ft

AOI02-01-SB-00-02-D

09/02/2021

0-2 ft

AOI01-03-SS-00-0.5

08/31/2021

0-0.5 ft

AOI01-04-SS-00-01

08/31/2021

0-1 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.

Interpreted Qualifiers

J = Estimated concentration

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

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.

Notes

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

Sample IDs with "-SS-" indicate a dedicated surface soil location, whereas IDs with "-SB-" indicate a soil boring location.

Limit of Detection (LOD) ranges for relevant constiuents reported as not detected (ND):

PFBS: 0.058-0.073 μg/kg

PFHxS: 0.116-0.146 μg/kg

AOI01 AOI02

AOI02-03-SS-00-02

09/01/2021

0-2 ft

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

AOI02-02-SB-00-02

09/01/2021

0-2 ft

AOI02-02-SB-00-02-D

09/01/2021

0-2 ft

AOI02-01-SB-00-02

09/02/2021

0-2 ft

AECOM 6-5
Table 6-2

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

Site Inspection Report, Tupelo AASF #2

Analyte OSD Screening 

Level a

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

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

PFHxS 130 ND U ND U ND U ND U ND U ND U

PFNA 19 ND U 0.049 J 0.029 J 0.069 J ND U ND U

PFOA 19 ND U 0.144 J ND U ND U ND U ND U

PFOS 13 0.077 J 0.082 J ND U 0.181 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

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. HQ hazard quotient

Sample IDs with "-SS-" indicate a dedicated surface soil location, whereas IDs with "-SB-" indicate a soil boring location. ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

Limit of Detection (LOD) ranges for relevant constiuents reported as not detected (ND): ND analyte not detected above the LOD

PFBS: 0.058-0.073 μg/kg OSD Office of the Secretary of Defense

PFHxS: 0.116-0.146 μg/kg QSM Quality Systems Manual

PFNA: 0.058-0.073 μg/kg Qual interpreted qualifier

PFOA: 0.231-0.292 μg/kg SB soil boring

PFOS: 0.231-0.292 μg/kg SS surface soil

TUP Tupelo

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

AOI02-06-SS-00-02

09/01/2021

0-2 ft

Area of Interest

Sample ID

Sample Date

Depth

AOI02-04-SS-00-02

09/01/2021

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

TUP-02-SB-00-02

09/01/2021

0-2 ft

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

AOI02-07-SS-00-01

09/01/2021

0-1 ft

TUP-01-SB-00-02

08/30/2021

0-2 ft

AOI02-05-SS-00-02

09/01/2021

0-2 ft

AECOM 6-6
Table 6-3

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

Site Inspection Report, Tupelo AASF #2

Analyte OSD Screening 

Level a

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 ND U ND U

PFHxS 1600 ND U ND U ND U ND U ND U ND U ND U ND U ND U

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

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

PFOS 160 ND U ND U ND U ND U ND U ND U ND U ND U ND U

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS perfluorobutanesulfonic acid

References PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Interpreted Qualifiers Acronyms and Abbreviations

U = The analyte was not detected at a level greater than or equal to the adjusted DL AASF Army Aviation Support Facility

AOI Area of Interest

Notes DL detection limit

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

HQ hazard quotient

ID identification

Limit of Detection (LOD) ranges for relevant constiuents reported as not detected (ND): LCMSMS liquid chromatography with tandem mass spectrometry

PFBS: 0.056-0.063 μg/kg LOD limit of detection

PFHxS: 0.112-0.127 μg/kg ND analyte not detected above the LOD

PFNA: 0.056-0.063 μg/kg OSD Office of the Secretary of Defense

PFOA: 0.224-0.254 μg/kg QSM Quality Systems Manual

PFOS: 0.224-0.254 μg/kg Qual interpreted qualifier

SB soil boring

TUP Tupelo

USEPA United States Environmental Protection Agency

μg/kg micrograms per kilogram

Area of Interest

Sample ID

Sample Date

Depth

AOI01-01-SB-06-08

08/31/2021

6-8 ft

AOI01-01-SB-11-13

08/31/2021

11-13 ft

AOI02-01-SB-5.25-7.25

09/02/2021

5.25-7.25 ft 7-9 ft

AOI02-01-SB-9.5-11.5

09/02/2021

9.5-11.5 ft

AOI02-02-SB-13-15

09/01/2021

13-15 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 industrial/commercial composite worker scenario for incidental ingestion of 

contaminated soil.

AOI01 AOI02 Sitewide

TUP-02-SB-3.5-5.5

09/01/2021

3.5-5.5 ft

TUP-02-SB-06-08

09/01/2021

6-8 ft

TUP-01-SB-02-04

08/30/2021

2-4 ft

TUP-01-SB-07-09

08/30/2021

AECOM 6-7
Table 6-4

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

Site Inspection Report, Tupelo AASF #2

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. PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

Limit of Detection (LOD) for relevant constiuents reported as not detected (ND): Acronyms and Abbreviations

PFBS: 0.059 μg/kg AASF Army Aviation Support Facility

PFHxS: 0.117 μg/kg AOI Area of Interest

PFNA: 0.059 μg/kg D duplicate

PFOA: 0.235 μg/kg DL detection limit

PFOS: 0.235 μg/kg ft feet

ID identification

LCMSMS liquid chromatography with tandem mass spectrometry

LOD limit of detection

ND analyte not detected above the LOD

QSM Quality Systems Manual

Qual interpreted qualifier

SB soil boring

μg/kg micrograms per kilogram

AOI02

AOI02-02-SB-38-40

09/01/2021

38-40 ft

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

AECOM 6-8
Table 6-5

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

Site Inspection Report, Tupelo AASF #2

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual Result Qual Result Qual

PFBS 601 3.82 J 3.11 J 11.7 11.3 1.39 J

PFHxS 39 1.29 J 9.11 43.1 42.2 ND U

PFNA 6 ND U 11.7 ND U ND U ND U

PFOA 6 7.75 68.4 2.61 J 2.60 J 1.19 J

PFOS 4 ND U 1.61 J 3.74 J 4.00 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. GW groundwater

HQ hazard quotient

ID identification

Limit of Detection (LOD) for relevant constiuents reported as not detected (ND): LCMSMS liquid chromatography with tandem mass spectrometry

PFBS: 2.00 ng/L LOD limit of detection

PFHxS: 3.00 ng/L ND analyte not detected above the LOD

PFNA: 2.00 ng/L OSD Office of the Secretary of Defense

PFOA: 2.00 ng/L QSM Quality Systems Manual

PFOS: 2.00 ng/L Qual interpreted qualifier

TUP Tupelo

USEPA United States Environmental Protection Agency

ng/l nanogram per liter

AOI01

AOI01-01-GW

09/03/2021

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

TUP-01-GW-D

09/02/2021

TUP-02-GW

09/03/2021

AOI02

AOI02-01-GW

09/08/2021

TUP-01-GW

09/02/2021

Area of Interest

Sample ID

Sample Date

AECOM 6-9
AECOM 6-10

Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

THIS PAGE INTENTIONALLY BLANK
W Jackson Street Ext

AOI02-02

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI01-02

AOI01-03

AOI01-04

AOI02-03

AOI02-04

AOI02-05

AOI02-06

AOI02-07

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

Shallow Intermediate Deep

­ Figure 6-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

4/10/2023

4/10/2023

4/10/2023

MS

SS

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)

4/10/2023

1:3,000

Legend

Facility Boundary

River/Stream

PFOA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

0 125 250 500

Feet

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

The soil depth interval for each sample is presented on Table 5-1.

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 6-11
W Jackson Street Ext

AOI02-02

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI01-02

AOI01-03

AOI01-04

AOI02-03

AOI02-04

AOI02-05

AOI02-06

AOI02-07

0 125 250 500

Feet

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

Shallow Intermediate Deep

­ Figure 6-2

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

4/10/2023

4/10/2023

4/10/2023

MS

SS

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)

4/10/2023

1:3,000

Legend

Facility Boundary

River/Stream

PFOS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

PFOS Results (μg/Kg)

ND

>ND - 13

>13 - 160

>160 - 1,600

>1,600

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

The soil depth interval for each sample is presented on Table 5-1.

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

AECOM 6-12
W Jackson Street Ext

AOI02-02

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI01-02

AOI01-03

AOI01-04

AOI02-03

AOI02-04

AOI02-05

AOI02-06

AOI02-07

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

Shallow Intermediate Deep

­ Figure 6-3

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

4/10/2023

4/10/2023

4/10/2023

MS

SS

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)

4/10/2023

1:3,000

Legend

Facility Boundary

River/Stream

PFBS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

0 125 250 500

Feet

PFBS Results (μg/Kg)

ND

>ND - 10

>10 - 1,900

>1,900 - 25,000

>25,000

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

The soil depth interval for each sample is presented on Table 5-1.

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

AECOM 6-13
W Jackson Street Ext

AOI02-02

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI01-02

AOI01-03

AOI01-04

AOI02-03

AOI02-04

AOI02-05

AOI02-06

AOI02-07

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

Shallow Intermediate Deep

­ Figure 6-4

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

4/10/2023

4/10/2023

4/10/2023

MS

SS

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)

4/10/2023

1:3,000

Legend

Facility Boundary

River/Stream

PFHxS Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

0 125 250 500

Feet

PFHxS Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

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

The soil depth interval for each sample is presented on Table 5-1.

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

AECOM 6-14
W Jackson Street Ext

AOI02-02

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI01-02

AOI01-03

AOI01-04

AOI02-03

AOI02-04

AOI02-05

AOI02-06

AOI02-07

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

AOI02-02

Shallow Intermediate Deep

­ Figure 6-5

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

4/10/2023

4/10/2023

4/10/2023

MS

SS

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)

4/10/2023

1:3,000

Legend

Facility Boundary

River/Stream

PFNA Detections in Soil

12420 Milestone Center Drive

Germantown, MD 20876

0 125 250 500

Feet

PFNA Results (μg/Kg)

ND

>ND - 19

>19 - 250

>250 - 2,500

>2,500

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

The soil depth interval for each sample is presented on Table 5-1.

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

AECOM 6-15
W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

PFOA Results (ng/L)

ND

>ND - 6

>6 - 40

>40 - 70

>70

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

PFOA PFOS PFBS

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

0 125 250 500

Feet ­ Figure 6-6

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

10/5/2022

10/5/2022

10/5/2022

MS

SS

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)

10/5/2022

1:3,000

Legend

Facility Boundary

River/Stream

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.

AECOM 6-16
W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

PFHxS Results (ng/L)

ND

>ND - 39

>39 - 100

>100 - 1,000

>1,000

W Jackson Street Ext

AOI01-01

AOI02-01

TUP-01

TUP-02

PFHxS PFNA

PFNA Results (ng/L)

ND

>ND - 6

>6 - 100

>100 - 1,000

>1,000

0 125 250 500

Feet ­ Figure 6-7

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection at Tupelo AASF, MS

8/16/2022

8/16/2022

8/16/2022

MS

SS

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)

8/16/2022

1:3,000

Legend

Facility Boundary

River/Stream

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.

AECOM 6-17
AECOM 6-18

Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 7-1

7. Exposure Pathways

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

Figure 7-2. Please note that while the CSM discussion assists in determining if a receptor may 

be impacted, the decision to move from SI to Remedial Investigation (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 a 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 (although unlikely due to restricted access), residents outside the facility 

boundary, and recreational users outside of the facility boundary. On-facility residents are not 

anticipated in the foreseeable future.

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 and AOI 2 based on the aforementioned 

criteria. 

7.1.1 AOI 1

AFFF may have been released at AOI 1 during fire training activities and subsequent testing of 

the systems. AFFF was used at the Wash Rack during fire training, and mobile fire extinguishers 

containing AFFF were discharged to the apron stormwater drains. 
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 7-2

PFOA, PFOS, and PFNA were detected below their respective SLs in surface soil at AOI 1. Site 

workers, construction workers, and trespassers could contact constituents in surface soil via 

incidental ingestion and inhalation of dust. Therefore, the surface soil exposure pathway for site 

workers, construction workers, and trespassers are potentially complete. Additionally, nearby offfacility recreational users and off-facility residents may potentially be exposed to constituents via 

inhalation of dust. PFOA, PFOS, PFHxS, PFNA, and PFBS were not detected in subsurface soil 

at AOI 1. Therefore, all shallow subsurface pathways are considered incomplete. The CSM for 

AOI 1 is presented on Figure 7-1. 

7.1.2 AOI 2 

Due to a hardware malfunction approximately 800 gallons of AFFF were discharged at the AASF. 

The AFFF subsequently flowed out of the building, into the parking lot to the east, filled the eastern 

drainage ditches and retention pond, and eventually flowed out onto W Jackson Street; the foam 

was allowed to naturally dissipate. 

PFOA, PFOS, and PFNA were detected in surface soil at AOI 2. Site workers, construction 

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

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

workers, and trespassers are potentially complete. Additionally, nearby off-facility recreational 

users and off-facility residents may potentially be exposed to constituents via inhalation of dust.

PFOA, PFOS, PFHxS, PFNA, and PFBS were not detected in subsurface soil at AOI 2. Therefore, 

all shallow subsurface pathways are considered incomplete. The CSM for AOI 2 is presented on 

Figure 7-2. 

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.

No wells that collect water at depths less than 400 feet bgs have been identified downgradient of 

the AASF (MDEQQ, 2019b; USGS, 2019), suggesting that none of the identified downgradient 

wells are collecting water in the Coffee Sand aquifer. Drinking water at the AASF and the local 

area is supplied by the City of Tupelo, which purchases drinking water from the Northeast 

Mississippi Regional Water District, who obtains the water from the Tombigbee River, 

approximately 18 miles east of the facility. Therefore, the ingestion exposure pathway for offfacility residents and site workers is considered incomplete for both AOIs. Unique features of each 

AOI are presented below.

7.2.1 AOI 1

PFOA concentrations exceeded the groundwater SL in monitoring well AOI01-01. PFHxS and 

PFBS were detected in groundwater, at concentrations below SLs at AOI 1. Additionally, PFHxS 

and PFOS in groundwater exceeded their SLs at the upgradient, western facility boundary 

monitoring well TUP-01. Depths to water at the facility measured in September 2021 during the 

SI ranged from 4.94 to 11.29 feet bgs. Consequently, shallow groundwater may be encountered 

during future construction activities; therefore, the ingestion exposure pathway for construction 

workers is considered potentially complete. The CSM for AOI 1 is presented on Figure 7-1. 

7.2.2 AOI 2 

PFOA and PFNA exceeded their respective SLs in groundwater at monitoring well AOI02-01. 

PFOS, PFHxS, and PFBS were detected in groundwater, at concentrations below the SLs in 

AOI02-01. AOI 2 is also downgradient of AOI 1, and impacts at AOI 1 may potentially flow to AOI 
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 7-3

2. The ingestion exposure pathway for construction workers is considered potentially complete 

because water was encountered at shallow depths (less than 15 feet bgs) across the facility. The 

CSM for AOI 2 is presented on Figure 7-2. 

7.3 Surface Water and Sediment Exposure Pathway

The SI results in soil and groundwater, in combination with knowledge of the fate and transport 

properties of PFAS, were used to determine whether a potentially complete pathway exists 

between the source and potential receptors.

7.3.1 AOI 1

PFAS are water soluble and can migrate readily from soil to surface water via leaching and runoff. Because PFOA, PFOS, PFHxS, PFNA, and/or PFBS were detected in soil and groundwater 

at AOI 1, it is possible that those compounds may have migrated from soil and groundwater to 

on-facility drainage features and downgradient streams in the Kings Creek-Town Creek 

Watershed. Therefore, the surface water and sediment ingestion exposure pathways for site 

workers, construction workers, recreational users and trespassers are considered potentially 

complete. The CSM for AOI 1 is presented on Figure 7-1. 

7.3.2 AOI 2 

PFOA, PFOS, PFHxS, PFNA, and/or PFBS were detected in soil and groundwater at AOI 2; 

therefore, it is possible that those compounds may have migrated from soil and groundwater to 

on-facility drainage features and downgradient streams in the Kings Creek-Town Creek 

Watershed. Consequently, the surface water and sediment ingestion exposure pathways for site 

workers, construction workers, recreational users and trespassers are considered potentially 

complete. The CSM for AOI 2 is presented on Figure 7-2. 
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 7-4

 

THIS PAGE INTENTIONALLY BLANK
Media

SOURCE PATHWAY RECEPTOR

AOI 1

Fire Training

Areas and

Systems Testing

Surface Soil

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

Particulate

Surface Soil

at AOIs

Surface

Water/

Sediment

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

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

Worker Resident1 Trespasser/Recreational User1

Site

Worker

Construction

Worker Resident1 Trespasser/

Recreational User1

LEGEND

Figure 7-1

Conceptual Site Model, AOI 1

Western Release Areas

Potential

Off-Facility

Source Not

under

Control of

ARNG

/

/ /

Ingestion

/

/

/ / /

Notes:

1. The resident and recreational user

receptors refer to an off-site resident and

recreational user.

/ /

/

/

/

/ /

/

Subsurface

Soil

Shallow

Groundwater

/

/

/

/

7-5
Media

SOURCE PATHWAY RECEPTOR

AOI 2 Bladder Rupture Surface Soil

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

Particulate

Surface Soil

at AOIs

Surface

Water/

Sediment

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

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

Worker Resident1 Trespasser/Recreational User1

Site

Worker

Construction

Worker Resident1 Trespasser/

Recreational User1

LEGEND

Figure 7-2

Conceptual Site Model, AOI 2

Bladder Rupture Release

Potential

Off-Facility

Source Not

under

Control of

ARNG

/

/ /

Ingestion

/

/

/ / /

Notes:

1. The resident and recreational user

receptors refer to an off-site resident and

recreational user.

/

/

/ / /

/

/ /

Subsurface

Soil

Shallow

Groundwater

/

/

/

/

7-6
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, 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 27 August to 8 September 2021 and consisted of utility 

clearance, direct push boring, soil sample collection, permanent 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 previously noted in Section 5.8. 

To fulfill the project DQOs set forth in the approved SI QAPP Addendum (AECOM, 2021a), samples 

were collected and analyzed for a subset of 18 compounds by LC/MS/MS compliant with QSM 5.3 

Table B-15 as follows. 

• Twenty-three (23) soil samples from 13 boring locations;

• Four groundwater samples from four permanent monitoring wells;

• Sixteen (16) 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 is warranted in an RI for AOI 1 and AOI 2 (see 

Table 8-1). Based on the CSMs developed and revised in light of the SI findings, there is no

potential for exposure to drinking water receptors from AOI 1 and AOI 2 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:

• PFOA in groundwater exceeded the SL of 6 ng/L, with a concentration of 7.75 ng/L

at AOI01-01. PFHxS and PFBS were detected below their SLs in groundwater at AOI

1. PFHxS exceeded the SL of 39 ng/L at the upgradient facility boundary location

TUP-01, with a concentration of 43.1 ng/L. Based on the results of the SI, further

evaluation of AOI 1 is warranted in an RI.

• The detected concentrations of PFOA, PFOS, and PFNA in soil at AOI 1 were below

their respective SLs.

• At AOI 2:

• PFOA and PFNA were detected in groundwater above their SLs. PFOA exceeded

the SL of 6 ng/L, with a concentration of 68.4 ng/L. PFNA exceeded the SL of 6 ng/L,
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 8-2

with a concentration of 11.7 ng/L. PFOS, PFHxS, and PFBS were detected in 

groundwater below the SLs. Based on the results of the SI, further evaluation of AOI 

2 is warranted in an RI.

• The detected concentrations of PFOA, PFOS, and PFNA in soil at AOI 2 were below 

their SLs. 

Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA 

(commonly referred to as GenX) was not included as an analyte at the time of this SI. Based on the 

CSM developed during the PA and revised based on SI findings, the presence of HFPO-DA is not 

anticipated at the facility because HFPO-DA is generally not a component of MIL-SPEC AFFF and 

based on its history including distribution limitations that restricted use of GenX, it is generally not a 

component of other products the military used. In addition, it is unlikely that GenX would be an 

individual chemical of concern in the absence of other PFAS.

Table 8-1 summarizes the SI results for soil and groundwater used to determine if an AOI should 

be considered for further investigation under CERCLA and undergo an RI. 

Table 8-1: Summary of Site Inspection Findings and Recommendations

AOI

Potential 

Release 

Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater –

Facility 

Boundary

Future Action

1

Western 

Release 

Areas

Proceed to RI 

2

Bladder 

Rupture 

Release

Proceed to RI

Legend:

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected
Site Inspection Report

Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 9-1

9. References

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

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

W912DR17F0192. 9 March.

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

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

AECOM. 2020. Final Preliminary Assessment Report, Tupelo Army Aviation Support Facility No. 

2, Mississippi. July. 

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Addendum, Tupelo Army Aviation Support Facility No. 2, Tupelo, Mississippi, Perfluorooctane 

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

Nationwide. August.

AECOM. 2021b. Final Site Safety and Health Plan, Tupelo Army Aviation Support Facility No. 2, 

Tupelo, Mississippi, Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid 

(PFOA) Impacted Sites ARNG Installations, Nationwide. August.

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

6 July. 

Boswell, E.H. 1976. The Eutaw-McShan Aquifer in Mississippi: U.S. Geological Survey WaterWater Resources Investigations Open-File Report 76-134.

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

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EA Engineering Science and Technology, 2021. SOP No. 042A for Treating Liquid InvestigationDerived Material (Purge water, drilling water, and decontamination fluids).

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https://geology.deq.ms.gov/environmental/boreholes/. 
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Army Aviation Support Facility No. 2, Tupelo, Mississippi

AECOM 9-2

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Contamination in Mississippi: U.S. Geological Survey Hydrologic Investigations Atlas HA-739.

Strom, E.W., and Mallory, M.J. 1995. Hydrology and Simulation of Ground-water Flow in the 

Eutaw-McShan Aquifer and the Tuscaloosa Aquifer System in Northeastern Mississippi: U.S. 

Geological Survey Water-Resources Investigations Report 94-4223, 83 p.

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

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(CERCLA). 

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