FINAL

Site Inspection Report 

Papago Park Military Reservation

Phoenix, Arizona 

Perfluorooctanesulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

November 2021

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
 

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM i

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

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............................. 2-4

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

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

3.1 AOI 1....................................................................................................................... 3-1

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

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

4.2 Goals of the Study .................................................................................................. 4-1

4.3 Information Inputs ................................................................................................... 4-2

4.4 Study Boundaries ................................................................................................... 4-2

4.5 Analytical Approach ................................................................................................ 4-2

4.6 Data Usability Assessment ..................................................................................... 4-3

4.6.1 Precision ....................................................................................................... 4-3

4.6.2 Accuracy....................................................................................................... 4-4

4.6.3 Representativeness...................................................................................... 4-4

4.6.4 Comparability................................................................................................ 4-5

4.6.5 Completeness............................................................................................... 4-5

4.6.6 Sensitivity ..................................................................................................... 4-6

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 PFAS Sampling Equipment Acceptability ....................... 5-2

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

5.3 Groundwater Sampling ........................................................................................... 5-3

5.4 Synoptic Water Level Measurements ..................................................................... 5-3

5.5 Investigation-Derived Waste ................................................................................... 5-3

5.6 Laboratory Analytical Methods................................................................................ 5-4

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

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

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

6.2 Soil Physicochemical Analyses............................................................................... 6-1

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

6.3.1 AOI 1 Soil Analytical Results ........................................................................ 6-2
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM ii

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

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

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

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

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

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

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

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

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

8.2 SI Goals Evaluation ................................................................................................ 8-1

8.3 Outcome ................................................................................................................. 8-2

9. References..................................................................................................................... 9-1
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM iii

Appendices

Appendix A Data Validation Reports

Appendix B Field Documentation

B1. Log of Daily Notice of Field Activities

B2. Groundwater Sampling Forms

B3. Investigation-Derived Waste Polygon Locations 

 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 Surface Water Features

Figure 3-1 Area of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOA Detections in Surface Soil

Figure 6-2 PFOS Detections in Surface Soil

Figure 6-3 PFBS Detections in Surface Soil

Figure 6-4 PFOA, PFOS, and PFBS Detections in Groundwater

Figure 7-1 Conceptual Site Model, AOI 1

Tables

Table ES-1 Screening Levels (Soil and Groundwater)

Table ES-2 Summary of Site Inspection Findings

Table ES-3 Site Inspection Recommendations

Table 5-1 Site Inspection Samples by Medium

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

Table 6-1 Screening Levels (Soil and Groundwater)

Table 6-2 PFAS Detections in Surface Soil

Table 6-3 PFAS Detections in Groundwater

Table 8-1 Summary of Site Inspection Findings

Table 8-2 Site Inspection Recommendations
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM iv

Acronyms and Abbreviations

% percent

°C degrees Celsius

°F degrees Fahrenheit

μg/kg micrograms per kilogram

6:2 FTS 6:2 Fluorotelomer sulfonic acid

8:2 FTS 8:2 Fluorotelomer sulfonic acid

AASF Army Aviation Support Facility

ADEQ Arizona Department of Environmental Quality

AECOM AECOM Technical Services, Inc.

AFFF aqueous film forming foam

AOI Area of Interest

ARNG Army National Guard

ASTM American Society for Testing and Materials

AZARNG Arizona Army National Guard

AZDEMA Arizona Department of Emergency and Military Affairs

bgs below ground surface 

btoc below top of casing

CAP Central Arizona Project

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

DQI data quality indicator

DQO data quality objective

DUA data usability assessment

DVR data validation report 

EDRTM Environmental Data Resources, Inc.

TM

EEC Engineering and Environmental Consultants

EIS extraction internal standards

ELAP Environmental Laboratory Accreditation Program 

EM Engineer Manual

ERB equipment rinsate blank

FedEx Federal Express

FRB Field Reagent Blank

GPRS Ground Penetrating Radar Systems, LLC

HA Health Advisory

HDPE high-density polyethylene 

IDW investigation-derived waste

IIS injection internal standards

ITRC Interstate Technology Regulatory Council

LC/MS/MS liquid chromatography with tandem mass spectrometry

LCS laboratory control spike
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM v

LCSD laboratory control spike duplicate

LOQ limit of quantitation

MDL method detection limit

mg/Kg milligram per kilogram

MS matrix spike 

MSD matrix spike duplicate

NELAP National Environmental Laboratory Accreditation Program

NEtFOSAA N-ethyl perfluorooctanesulfonamidoacetic acid

ng/L nanograms per liter

NMeFOSAA N-methyl perfluorooctanesulfonamidoacetic acid

NOAA National Oceanic and Atmospheric Administration

OSD Office of the Secretary of Defense

PA Preliminary Assessment

PFAS per- and polyfluoroalkyl substances

PFBA perfluorobutyrate

PFBS perfluorobutanesulfonic acid

PFDA perfluorodecanoic acid

PFDoA perfluorododecanoic acid

PFHpA perfluoroheptanoic acid

PFHxA perfluorohexanoic acid

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PFPeA perfluoropentanoic acid

PFTeDA perfluorotetradecanoic acid

PFTrDA perfluorotridecanoic acid

PFUdA perfluoroundecanoic acid

PID photoionization detector

PPMR Papago Park Military Reservation

PQAPP Programmatic UFP-QAPP

QAPP Quality Assurance Project Plan

QC quality control

QSM Quality Systems Manual

RI Remedial Investigation

RPD relative percent differences

SI Site Inspection

SL screening level

SOP standard operating procedure

SRP Salt River Project

TCRA time-critical removal action

TOC total organic carbon

TPP Technical Project Planning

UCMR3 Unregulated Contaminant Monitoring Rule 3

UFP Uniform Federal Policy
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM vi

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
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM ES-1

Executive Summary

The Army National Guard (ARNG) G9 is performing Preliminary Assessments (PAs) and Site 

Inspections (SIs) at per- and polyfluoroalkyl substances (PFAS)-impacted sites at ARNG facilities 

nationwide. The objective of the SI at each facility is to identify whether there has been a release 

to the environment from the Areas of Interest (AOIs) identified in the PA and determine the 

presence or absence of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and 

perfluorobutanesulfonic acid (PFBS) at or above screening levels (SLs). An SI was completed at 

Papago Park Military Reservation (PPMR) in Phoenix, Arizona. PPMR will be referred to as the 

“facility” throughout this document. 

PPMR occupies approximately 480 acres in the eastern portion of Maricopa County, Arizona, 

within the City of Phoenix. The PFAS PA identified four potential release areas which were 

grouped into one AOI and investigated during the SI. The SI field activities were conducted from 

19 April to 22 April 2021 and included surface soil sampling and groundwater sampling from 

existing monitoring wells. 

To fulfill the project Data Quality Objectives (DQOs) set forth in the approved SI Quality Assurance 

Project Plan (QAPP) Addendum (AECOM, 2021a), samples were collected and analyzed for a 

subset of 18 PFAS by liquid chromatography with tandem mass spectrometry (LC/MS/MS)

compliant with Quality Systems Manual (QSM) 5.3 Table B-15. The 18 PFAS analyzed as part of 

the ARNG SI program are specified in Section 5.7 of this Report. 

The Department of Defense (DoD) has adopted a policy to retain facilities in the Comprehensive 

Environmental Response, Compensation, and Liability Act (CERCLA) process based on riskbased SLs for soil and groundwater, as described in a memorandum from the Office of the 

Secretary of Defense (OSD) dated 15 September 2021 (Assistant Secretary of Defense, 2021). 

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 and there is a release identified that is likely attributed to ARNG activities, the AOI 

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

apply to three compounds: PFOS, PFOA, and PFBS.

The SLs are presented in Table ES-1 below. All other results presented in this report are 

considered informational in nature and serve as an indication as to whether soil and groundwater

contain or do not contain the 18 PFAS analyzed within the boundaries of the facility. 

Sample chemical analytical concentrations were compared against the project SLs as described 

in Table ES-1. A summary of the results of the SI data relative to the SLs is as follows: 

• PFOA and PFOS were detected in groundwater at AOI 1 and exceeded the individual SL 

of 40 nanograms per liter (ng/L), with maximum concentrations of 292 ng/L and 170 ng/L 

at locations MW-25 and MW-26, respectively. PFBS was also detected in groundwater at 

AOI 1, but it did not exceed the SL. Based on the results of the SI, further evaluation of 

AOI 1 is warranted in a Remedial Investigation (RI). 

• The detected concentrations of PFOA, PFOS, and PFBS in soil samples from the AOI 

were below the SLs.

Table ES-2 summarizes the SI results for soil and groundwater. Based on the conceptual site 

model (CSM) developed and revised in light of the SI findings, there is a potential for exposure to 

receptors caused by DoD activities at the facility.

Table ES-3 summarizes the rationale used to determine if an AOI should be considered for further 

investigation under CERCLA and undergo an RI. Based on the results of this SI, further evaluation 

is warranted in an RI for AOI 1.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM ES-2

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

Analyte

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 130 1,600 40

PFOS 130 1,600 40

PFBS 1,900 25,000 600

Notes:

a.) Assistant Secretary of Defense, 2021. Risk Based Screening Levels Calculated for PFOS, PFOA, PFBS in Groundwater and Soil using 

United States Environmental Protection Agency’s (USEPA’s) Regional Screening Level Calculator. Hazard Quotient (HQ) = 0.1. 15

September 2021. 

Notes: 

μg/kg = micrograms per kilogram

bgs = below ground surface

ng/L = nanograms per liter

Table ES-2: Summary of Site Inspection Findings

AOI Potential PFAS 

Release Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater –

Facility 

Boundary

1 

Army Aviation and 

Support Facility #1 and 

Vicinity

N/A

Legend:

N/A = Not applicable 

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected

Table ES-3: Site Inspection Recommendations

AOI Description Rationale Future Action

1 

Army Aviation and 

Support Facility #1 

and Vicinity

Exceedances of SLs in groundwater within 

permanent monitoring wells at the facility 

boundary. No exceedances of SLs in soil. 

Proceed to RI 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 1-1

1. Introduction

1.1 Project Authorization

The Army National Guard (ARNG) G9 is the lead agency in performing Preliminary Assessments 

(PAs) and Site Inspections (SIs) for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic 

acid (PFOA) at Impacted Sites, ARNG Installations, Nationwide. This work is supported by the 

United States (US) Army Corps of Engineers (USACE) Baltimore District and their contractor, 

AECOM Technical Services, Inc. (AECOM), under Contract Number W912DR-12-D-0014, Task 

Order W912DR17F0192, issued 11 August 2017. The ARNG performed this SI at Papago Park 

Military Reservation (PPMR) in Phoenix, Arizona. PPMR is 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; 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 including specific 

requirements for sampling for PFOA, PFOS, and perfluorobutanesulfonic acid (PFBS), and the 

group of related compounds known in the industry as per- and polyfluoroalkyl substances (PFAS). 

The term PFAS is used throughout this report to encompass all PFAS chemicals being evaluated, 

including PFOA, PFOS, and PFBS, which are the key components of the suspected releases 

being evaluated, and the other 15 related compounds listed in the task order. 

1.2 SI Purpose

A PA was performed at PPMR (AECOM, 2020) that identified four potential PFAS release areas 

and grouped them into one Area of Interest (AOI). The objective of the SI is to identify whether 

there has been a release to the environment from the AOI and determine the presence or absence 

of PFOA, PFOS, and PFBS at or above screening levels (SLs). 

As stated in the Federal Facilities Remedial Site Inspection Summary Guide (USEPA, 2005), an 

SI has five goals: 

1. Develop information to potentially eliminate a release from further consideration because 

it is determined that it poses no significant threat to human health or the environment;

2. Determine the potential need for a removal action;

3. Collect or develop data to evaluate potential release;

4. Collect data to better characterize the release for more effective and rapid initiation of a 

Remedial Investigation (RI), if determined necessary; and

5. Collect data to determine whether the release is more than likely the result of activities 

associated with the Department of Defense (DoD). 

In addition to the USEPA-identified goals of an SI, the ARNG SI also identifies whether there are 

potential off-facility PFAS sources. 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 1-2

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 2-1

2. Facility Background

2.1 Facility Location and Description 

PPMR occupies approximately 480 acres in the eastern portion of Maricopa County, about 7 miles 

east of downtown Phoenix and 1.5 miles from Phoenix Sky Harbor International Airport (Figure 

2-1). The properties south and east of PPMR are public parks and recreational areas owned by 

the City of Phoenix (Arizona Department of Environmental Quality [ADEQ], 2018). Residential 

properties are to the north and west of PPMR. 

PPMR has been an active military facility and rifle range since its congressional designation in 

1930. PPMR serves as the Joint Forces Headquarters for the Arizona ARNG (AZARNG) and also 

hosts operational National Guard units at the installation. The current and historical activities at 

the installation include training and administration, aircraft fueling and maintenance activities, 

motor vehicle fueling and maintenance activities, fuel and solvent storage areas, gunnery ranges, 

detonation areas, and bunkers. The AZARNG leases portions of the installation to the US Air 

Force for administrative and training purposes (ADEQ, 2018). Historical records indicate that two

runways existed at the installation. One runway was oriented 080°/260° and was 3,500 feet long, 

and the second runway was oriented 0°/180°. According to the Arizona Department of Emergency 

and Military Affairs (AZDEMA), the second runway is abandoned and has not been used by any 

fixed-wing aircraft for several decades. An active helicopter landing pad and taxiway have 

operated at PPMR since 1974.

2.2 Facility Environmental Setting

PPMR is located in the eastern portion of Maricopa County, Arizona and is approximately 1,242 

feet above sea level (Figure 2-2). Major geographic features near PPMR are the Barnes Buttes 

to the east, the Salt River, which flows westerly about 2.5 miles to the south, the Old 

Crosscut Canal, located along 46th Street, and the Grand Canal, which flows northwesterly 

through the area west of 40th Street and Van Buren Street. The majority of the installation is 

developed with buildings, concrete, and asphalt features, with the exception of an area to the 

east, which is undeveloped, and a retention basin that lies to the south-central portion of the 

installation.

2.2.1 Geology

PPMR is constructed on a Quaternary pediment (colluvium/alluvium) that originated from the 

western and southwestern flanks of Barnes Butte. The pediment is the erosional remnant of the 

upthrown fault block, which has been cut by several smaller northwest-trending faults 

(Engineering and Environmental Consultants [EEC], 2005). 

Bedrock in the area around and including PPMR is covered by a thin colluvium/alluvium veneer 

up to 30 feet thick in some areas. The bedrock is composed of calichified angular to subangular 

sediments and rock fragments. Tertiary sedimentary rocks exposed at PPMR indicate a variation 

of sediment sources and reflect separate lobes of alluvial fans that coalesce with and overlie each 

other. The older, proximal facies are members of the Camel’s Head Formation (Stadium Breccia, 

Barnes Butte Breccia, Zoo Breccia) and are typically very coarse and poorly stratified arkosic 

breccias, having originated as talus, mud flows, and debris flows. Mid-fan facies are represented 

by the Papago Park member and consist of water-laid deposits that were interbedded with debris 

flow deposits. Distal-facies are represented by the Tempe Beds, which are finer-grained, wellstratified, and well-sorted (TechLaw, 2004). 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 2-2

Basement rocks beneath PPMR consist of Proterozoic Porphyritic Camelback granite, which is 

characterized by large feldspar crystals, and metarhyolite. Metarhyolitic rocks consist of gray to 

pink, blocky, low-grade, metamorphosed rhyolite, which are common throughout the subsurface 

of PPMR (EEC, 2005).

The soils at PPMR are composed of fine- to medium-grained sands. Variable amounts of clay,

silt, and gravel are also present. Intervals of gravel or gravel and sand/silt mixtures are present at 

depths greater than 10 feet below ground surface (bgs). The content of the gravel and sand is 

indicative of weather and eroded material originating from proximal sources of exposed bedrock 

around the facility. The thickness of soil/alluvium varies across PPMR; however, thicker deposits 

are typically found in the western portions of the facility (TechLaw, 2004). 

In addition to the soil and alluvial material described above, many areas at PPMR have been 

overlain with variable amounts of backfill or artificial cover during the operational history of the 

installation. The types of artificial fill material found at PPMR range in content from pea gravel to 

aggregate base course (TechLaw, 2004).

2.2.2 Hydrogeology

PPMR lies within the West Salt River Valley area of the Phoenix Active Management Area. Since 

1947, groundwater extraction for irrigation has lowered groundwater levels and caused changes 

in regional and local flow directions. Despite these changes, groundwater movement is still 

primarily westward toward the Salt River and Gila Rivers, as seen in Figure 2-3 (ADEQ, 2017). 

PPMR is on a bedrock highland that is underlain by crystalline rock. Consequently, very little 

water, if any, is present beneath the facility. Water-saturated layers have been historically 

identified at points near the western margin of PPMR from 6 to 42 feet bgs; however, a continuous 

groundwater zone does not appear to exist beneath most of the facility. Based on lithologic logs 

from historical monitoring wells, the main occurrence of groundwater exists under unconfined 

conditions within fractured Precambrian Camelback granite and/or metarhyolite. In some portions 

of PPMR, locally perched groundwater layers are found in the artificial fill material and calichified 

pediment colluvium/alluvium (EEC, 2005). 

Water level measurements were collected from four existing monitoring wells during the SI. Depth 

to water readings ranged from 14.41 feet below top of casing (btoc) to 20.71 feet btoc. A 

groundwater flow contour map was drafted using groundwater elevations calculated from existing 

survey data and the synoptic gauging data; however, the limited number and spatial coverage of 

the monitoring wells gauged did not provide a representative understanding of groundwater flow 

across the area. As a result, no groundwater contour map is included in this SI Report.

According to data received from ADEQ and the Environmental Data Resources, Inc.TM (EDRTM) 

report for PPMR, several dozen wells are located within a 4-mile radius of the facility. The majority 

of these wells are classified as monitoring wells and are not screened within the target interval of 

this SI. Several wells are listed as exempt, non-exempt, or other type of wells. Records from the 

AZDEMA indicate that there are 25 monitoring wells, and no drinking water or irrigation wells are 

present at or downgradient of the facility. The State of Arizona describes exempt wells as small, 

non-irrigation wells typically used to provide water for domestic purposes and non-exempt wells 

as a well drilled within an Active Management Area pursuant to different groundwater rights. 

Based on the USEPA’s Unregulated Contaminant Monitoring Rule 3 (UCMR3) data, no PFAS 

were detected in a public water system above the Health Advisory (HA) within 20 miles of the 

facility (USEPA, 2017a). The HA is 70 nanograms per liter (ng/L) for PFOA and PFOS, individually 

or combined. PFAS analyses performed in 2016 had method detection limits (MDLs) that were 

higher than currently achievable. Thus, it is possible that low concentrations of PFAS were not 

detected during the UCMR3 but might be detected if analyzed today.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 2-3

2.2.3 Hydrology

The City of Phoenix water supply comes primarily from the Salt River Project (SRP), which brings 

water by canal and pipeline from the Salt and Verde Rivers, and the Central Arizona Project

(CAP), which transports Colorado River water. Approximately 3 percent (%) of the water supply 

comes from groundwater. The City of Phoenix also uses a portion of its reclaimed effluent to 

maintain parks and for recharging local groundwater aquifers. The surface water near PPMR 

flows generally northeast to southwest (TechLaw, 2004).

The Salt River is the principal drainage feature of the Phoenix Basin and is the nearest surface 

water body to the facility, approximately 2.5 miles south of PPMR. The Salt River is typically dry 

throughout the greater Phoenix metropolitan area due to flood control/water retention structures; 

however, the river occasionally flows after heavy rainfall events or controlled releases from 

upstream structures (GEC-SA&B, 2005). There are surface water features onsite at PPMR; 

however, there are no perennial surface water bodies. Surface water drainage at PPMR runs from 

the northern portion of the facility (north of East McDowell Road), through a culvert under East 

McDowell Road, to a retention basin on the southern part of the installation (south of East 

McDowell Road). Prior to 1987, the Water Retention Basin (84748) located on the southern part 

of the facility did not exist. Surface water from PPMR may have flowed southwest and flooded the 

Motorola complex during extreme or high precipitation events; however, in 1987, the retention 

basin was reconfigured to hold surface flow and stormwater coming from the northern portion of 

PPMR. Surface water and stormwater entering the retention basin from the northern portion of

PPMR either evaporates (due to the high rates of evapotranspiration in Arizona) or infiltrates. 

Surface water features near the facility are shown in Figure 2-4. 

2.2.4 Climate

PPMR is situated in central Arizona, and the climate is characterized as arid, with low annual 

rainfall and low relative humidity. Daytime temperatures are high through the summer months. 

Winters are mild, and temperatures can drop below freezing during winter months (Arizona State 

Climate Office, 2019). There are two rainfall seasons. The first rainfall season occurs during winter 

months, from November through March, when the area is subject to storms from the Pacific 

Ocean. The second rainfall season occurs during July and August, when Arizona is subject to 

thunderstorms whose moisture originates in the Gulf of Mexico, in the Pacific Ocean, off the west 

coast of Mexico, and the Gulf of California. Although these periods are classified as rainy seasons, 

there can be periods of a month or more in any season when zero to less than one inch of 

precipitation occurs. Although rare, light snow occurs in the higher mountains surrounding the Salt 

River Valley (Arizona State Climate Office, 2019). The maximum average monthly temperature in 

nearby Phoenix, Arizona occurs in July (106.1 degrees Fahrenheit [°F]), with an average 

maximum annual temperature of 86.6°F. The minimum average monthly temperature occurs in 

December (44.8 °F), with an average minimum annual temperature of 63.4°F. The average annual 

precipitation in Phoenix, Arizona from 1981-2010 was 8.03 inches (National Oceanic and 

Atmospheric Administration [NOAA], 2019).

2.2.5 Current and Future Land Use

PPMR is federally owned and operated by AZARNG and has been an active military installation 

and rifle range since its congressional designation in 1930. Currently, the facility is used for 

training and administration, aircraft fueling and maintenance activities, motor vehicle fueling and 

maintenance activities, fuel and solvent storage areas, gunnery ranges, detonation areas, and 

bunkers. The facility development includes numerous structures, open storage areas, and training 

areas, including two abandoned runways and active heliport. Land surrounding the facility is 

mostly a mix of residential, recreational, and light industrial use. According to the City of Phoenix 

Zoning Database, the facility is zoned for R1-6, single family residential; however, it is a military 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 2-4

industrial complex that will not be used for residential development. Reasonably anticipated future 

land use is not expected to change from the current land use, and the facility will continue to be 

used as a military industrial complex.

2.2.6 Sensitive Habitat and Threatened/ Endangered Species 

The following birds, reptiles, insects, and fish are federally endangered, threatened, proposed, 

and/ or are listed as candidate species likely to be found at PPMR (US Fish and Wildlife Service

[USFWS] IPCA, 2021). 

• Birds: 

• Yuma Ridgways (clapper) rail, Rallus obsoletus [longirostris] yumanensis

(endangered)

• Yellow-billed Cuckoo, Coccyzus americanus (threatened)

• Southwestern willow flycatcher, Empidonax traillii extimus (endangered)

• California least tern, Sterna antillarum browni (endangered)

• Reptiles: 

• Sonoran Desert Tortoise, Gopherus morafkai (candidate)

• Insects: 

• Monarch Butterfly, Danaus plexippus (candidate)

• Fish: 

• Roundtail Chub, Gila robusta (candidate)

2.3 History of PFAS Use 

Four potential release areas were identified where PFAS were potentially released to soil within 

the boundary of PPMR through fire training exercises and storm water conveyance (AECOM, 

2020). Fire training, equipment testing, and aqueous film forming foam (AFFF) storage occurred 

at PPMR from the 1970s to mid-2000s. Presently, AFFF is no longer stored at the facility, and 

current mobile fire extinguishers have been tested and do not contain AFFF. The four potential 

release areas were grouped into one AOI (AOI 1). A description of AOI 1 is presented in Section 

3. 
CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

AB

4/23/2020

4/23/2020

NOTES Site Inspection for PFAS at Papago Park Military Res, AZ

1

4/23/2020

:633,600 ­ Figure 2-1

PM RG 4/23/2020

12420 Milestone Center Drive

Germantown, MD 20876

Facility Location

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

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

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_QAPP\Fig_10-1_Papago_Facility_Location.mxd

^_

0 5 10 20

Miles

Legend

Facility Boundary

Papago Park Military Reservation

AECOM 2-5
CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

AB

6/24/2021

6/24/2021

NOTES Site Inspection for PFAS at Papago Park Military Res, AZ

1:10,200

6/24/2021 ­ Figure 2-2

PM CM 6/24/2021

12420 Milestone Center Drive

Germantown, MD 20876

Facility Topography

Base Map: USGS The National Map: National

Boundaries Dataset, 3DEP Elevation Program,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Fig_2-2_Papago_SI_Facility_Topo.mxd

0 300 600 1,200

Feet

Legend

Facility Boundary

AECOM 2-6
Legend

Facility Boundary

Inferred Groundwater

Flow Direction

Geology

Holocene Surficial

Deposits

Late and Middle

Pleistocene Surficial

Deposits

Middle Miocene to

Oligocene

Sedimentary Rocks

Proterozoic Granitic

Rocks

0 0.75 1.5 3

Miles

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Fig_2-3_Papago_SI_Geology_Groundwater.mxd

Geology and Groundwater Features

Figure 2-3 12420 Milestone Center Drive ­ Germantown, MD 20876

CLIENT

REVISED

SCALE

8/18/2021 MS

AB

8/18/2021

8/18/2021

ARNG

GIS BY

CHK BY

PROJECT Site Inspection for PFAS at Papago Park Military Res, AZ

PM CM 8/18/2021

1:95,040

Base Map: Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS,

USDA, USGS, AeroGRID, IGN, and the GIS User Community

AECOM 2-7
Culvert SW of 5201

Sediment Trap Culvert SE of 5201

Lower Indian

Bend Wash

Watershed

Tempe Town

Lake-Salt

River Watershed

City of

Phoenix-Salt

River Watershed

Grand Canal

Old

Cross Cut Canal

Arizona

Cross

Cut

Canal

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_QAPP\Fig_10-3_Papago_Surface_Water.mxd

0 0.25 0.5 1

Miles

Legend

Facility Boundary

Water Body

Canal/Ditch

Surface Water Flow Direction

Surface Water Features

12420 Milestone Center Drive ­ Germantown, MD 20876 Figure 2-4

CLIENT

REVISED

SCALE

4/23/2020 MS

AB

4/23/2020

4/23/2020

ARNG

GIS BY

CHK BY

PROJECT Site Inspection for PFAS at Papago Park Military Res, AZ

PM RG 4/23/2020

1:31,680

Base Map: Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS,

USDA, USGS, AeroGRID, IGN, and the GIS User Community

Salt River

AECOM 2-8
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 3-1

3. Summary of Areas of Interest 

This section presents a summary of each potential PFAS release area by AOI. Based on the PA 

findings, four potential PFAS release areas were identified at PPMR and were grouped into one

AOI. The potential PFAS release areas are shown on Figure 3-1. 

3.1 AOI 1 

AOI 1 encompasses the general location in which fire training, equipment testing, and AFFF 

storage occurred at PPMR. These activities all occurred in close enough proximity of each other 

to be considered a single AOI. The AOI includes the former fire truck bay, flight line/main ramp, 

former storage area, and fuel point station.

The Former Fire Truck Bay is located within Army Aviation Support Facility (AASF) #1 ( M5201). 

This building housed a single standard crash fire rescue truck and related equipment for the 

airfield from the time the building was constructed in 1973 until the mid-2000s, when it was

converted into a gym. According to personnel interviews, the former fire truck bay stored AFFF, 

but it is unclear what methods of storage or handling were used. No suspected discharge of AFFF 

has been recorded in historical documents related to this potential release area, but personnel 

interviewed indicated that a discharge had occurred on site (within the boundary of the defined 

AOI). 

From the 1970s to the mid-2000s, the nozzle on the crash fire rescue truck was tested weekly 

using AFFF. The testing occurred on the Runway (M5228) and Rotary Wing Parking Apron 

(M5204), which originally was exposed soil until it was paved in 1973. According to the 

interviewee, once the foam was deployed, it was allowed to dry on the exposed soil. The 

equipment was rinsed, and any water that did not infiltrate or evaporate flowed south towards 

East McDowell Road and a stormwater culvert (the stormwater culvert likely did not exist prior to 

1973). Water from this culvert flows underneath East McDowell Road and discharges into the 

retention basin on the south side of East McDowell Road. 

According to interviews, a second former storage area was located just outside of the AASF #1 (

M5201 Exterior). Notes from the PA identified this area as a current picnic area, and the area is 

labeled ‘ M5201 Exterior’ on Figure 3-1. In this area, bulk containers of AFFF were stored in a 

covered area on the ground surface. The area no longer contains these storage containers and 

is now an open patch of land. No suspected discharge of AFFF has been recorded in historical 

documents related to this potential release area, but personnel interviewed indicated that a 

release had occurred on site (within the boundary of the defined AOI).

In addition to training with the former fire truck, Tri-MaxTM mobile extinguishers were used at the 

AASF #1 for a number of years; however, the exact number of units is unknown. The units were 

reported to have been stored near the flight line/main ramp when in use. The mobile extinguishers 

were demilled before disposal at the adjacent vehicle maintenance area, but it is unknown if the 

contents of the units were captured and disposed or released to the ground surface.

The Fuel Point Station located on PPMR is used to refuel various vehicles and machinery. This 

area is labeled ‘Mobile Fire Extinguishers’ on Figure 3-1. Tri-MaxTM and other mobile fire 

extinguishers have historically been and are currently located at the fuel point. At the time of the 

PA, the mobile extinguishers were inspected and determined to be non-AFFF fire extinguishers. 

It is unknown if mobile extinguishers used in the past contained AFFF.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 3-2

THIS PAGE INTENTIONALLY BLANK
Stormwater Retention Basin

Building M5201

Building M5201 Exterior Sediment Trap

Culvert SW of 5201

Culvert SE of 5201

Mobile Fire Extinguishers

M5228 M5204

2nd St Superfund Site

AOI 1

Arizona

Cross Cut Canal

Old Cross Cut Canal

Lower Indian

Bend Wash

Watershed City of

Phoenix-Salt

River Watershed

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_QAPP\Fig_10-4_Papago_AOIs.mxd

0 0.125 0.25 0.5

Miles

Legend

Area of Interest

Potential PFAS Release

Facility Boundary

Water Body

Canal/Ditch

Surface Water Flow

Direction

Inferred Groundwater

Flow Direction

Area of Interest

12420 Milestone Center Drive Figure 3-1 ­ Germantown, MD 20876

CLIENT

REVISED

SCALE

2/3/2021 MS

AB

2/3/2021

2/3/2021

ARNG

GIS BY

CHK BY

PROJECT Site Inspection for PFAS at Papago Park Military Res, AZ

PM RG 2/3/2021

1:15,840

Base Map: Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS,

USDA, USGS, AeroGRID, IGN, and the GIS User Community

AECOM 3-3
AECOM 3-4

Site Inspection Report

Papago Park Military Reservation, Arizona 

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 4-1

4. Project Data Quality Objectives

Project Data Quality Objectives (DQOs) are qualitative and quantitative statements that specify 

the quality of data and define the level of certainty required to support the project decision-making

process. The specific DQOs established for this facility are described below. These DQOs were 

developed in accordance with the USEPA’s seven-step iterative process (USEPA, 2006). 

4.1 Problem Statement

The following problem statement was developed during project planning:

The presence of PFAS, which may pose a risk to human health or the environment, in 

environmental media at the facility is currently unknown. PFAS are classified as emerging 

environmental contaminants that are garnering increasing regulatory interest due to their potential 

risks to human health and the environment. The regulatory framework for managing PFAS at both 

the federal and state level continues to evolve. 

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 Office of the Secretary of 

Defense (OSD) dated 15 September 2021 (Assistant Secretary of Defense, 2021). 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 three compounds: PFOS, PFOA, and PFBS.

The following quotes from the DA policy documents form the basis for this project (DA, 2016; DA, 

2018): 

• “The Army will research and identify locations where PFOS- and/or PFOA-containing 

products, such as AFFF, are known or suspected to have been used. Installations shall 

coordinate with installation/facility fire response or training offices to identify AFFF use or 

storage locations. The Army will consider FTAs, AFFF storage locations, hangars/buildings 

with AFFF suppression systems, fire equipment maintenance areas, and areas where 

emergency response operations required AFFF use as possible source areas. In addition, 

metal plating operations, which used certain PFOS-containing mist suppressants, shall be 

considered possible source areas.” 

• “Based on a review of site records...determine whether a CERCLA PA is appropriate for 

identifying PFOS/PFOA release sites. If the PA determines a PFOS/PFOA release may 

have occurred, a CERCLA SI shall be conducted to determine presence/absence of 

contamination.” 

• “Identify sites where perfluorinated compounds are known or suspected to have been 

released, with the priority being those sites within 20 miles of the public systems that tested 

above USEPA HA levels.” (USEPA, 2016a; USEPA, 2016b).

4.2 Goals of the Study

The following goals were established for this SI:

1. Determine the presence or absence of PFOA, PFOS, and PFBS at or above SLs.

2. Develop information to potentially eliminate a release from further consideration because 

it is determined that it poses no significant threat to human health or the environment.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 4-2

3. Determine the potential need for a time-critical removal action (TCRA) (applies to drinking 

water only). The primary actions that will be considered include provision of alternative 

water supplies or wellhead treatment. 

4. Collect data to better characterize the release areas for more effective and rapid initiation 

of an RI (if determined necessary).

5. If PFOA, PFOS, and PFBS are determined to be present, aim to evaluate whether the 

concentrations can be attributed to on-facility or off-facility sources that were identified 

within 4 miles of the installation as part of the PA (e.g., fire stations, major manufacturers, 

other DoD facilities).

6. Determine whether a potentially complete pathway exists between the source and 

potential receptors and whether ARNG is the likely source of the contamination. 

4.3 Information Inputs

Primary information inputs included:

• The PA for PPMR, Arizona (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)-Quality Assurance Project Plan (QAPP) 

Addendum (AECOM, 2021a); and

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

parameters measured at the time of sampling. 

4.4 Study Boundaries

The scope of the SI was bounded by the property limits of the facility (Figure 2-1). 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).

4.5 Analytical Approach

Samples were analyzed by Pace Analytical Gulf Coast, accredited under the 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 and decision rules as defined in the SI QAPP Addendum (AECOM, 

2021a). These rules governed response actions based on the results of the SI sampling effort.

The decision rules described in the Worksheet #11 of the SI QAPP Addendum identify actions 

based on the following:

Groundwater:

• Is there a human receptor within 4 miles of the facility? 

• What is the concentration of PFOA, PFOS, and PFBS at the potential release areas? 

• What is the concentration of PFOA, PFOS, and PFBS at the facility boundary upgradient 

and downgradient of the potential release areas? 

• What does the conceptual site model (CSM) suggest in terms of source, pathway and 

receptor? 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 4-3

Soil:

• What is the concentration of PFOA, PFOS, and PFBS in shallow surface soil (0 to 2 feet 

bgs)? 

• What is the concentration of PFOA, PFOS, and PFBS in deep soil (i.e., capillary fringe)?

• What does the CSM suggest in terms of source, pathway, and receptor? 

Soil and groundwater samples were collected from each of the potential release areas. 

Groundwater was encountered in existing wells at approximately 14 to 21 feet bgs. 

4.6 Data Usability Assessment

The Data Usability Assessment (DUA) 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 facility-specific DQOs. Both 

field sampling and analytical activities are assessed to determine whether the collected data are 

of the right type, quality, and quantity to support the decision-making (DoD, 2019a; DoD, 2019b;

USEPA, 2017b). 

Data Quality Indicators (DQIs) (Precision, Accuracy, Representativeness, Comparability, 

Completeness and Sensitivity) are important components in assessing data usability. These DQIs 

were evaluated in the subsequent sections and demonstrate that the data presented in this SI 

report are of high quality. Although the SI data are considered reliable, some degree of uncertainty 

can be associated with the data collected. Specific factors that may contribute to the uncertainty 

of the data evaluation are described below. The Data Validation Report (DVR) (Appendix A) 

presents explanations for all qualified data in greater detail.

4.6.1 Precision

Precision is the degree of agreement among repeated measurements of the same characteristic 

on the same sample or on separate samples collected as close as possible in time and place. 

Field sampling precision is measured with the field duplicate relative percent differences (RPD); 

laboratory precision is measured with calibration verification, internal standard recoveries, 

laboratory control spike (LCS), and matrix spike (MS) duplicate RPD.

Extraction internal standards (EIS) were added by the laboratory during sample extraction to 

measure relative responses of target analytes and used to correct for bias associated with matrix 

interferences and sample preparation efficiencies, injection volume variances, mass spectrometry 

ionization efficiencies, and other associated preparation and analytical anomalies. The field 

sample results associated with EIS area counts less than the lower quality control (QC) limit were 

non-detect and were as estimated values with a negative bias. 

Injection internal standards (IIS) were added by the laboratory after sample extraction and prior 

to analysis as a requirement of DoD Quality Systems Manual (QSM) 5.3 to measure relative 

responses of target analytes. The IIS samples were within the project established precision limits 

presented in the QAPP Addendum (AECOM, 2021a). 

LCS/LCS duplicate (LCSD) pairs were prepared by addition of known concentrations of each 

analyte in a matrix-free media known to be free of target analytes. LCS/LCSD pairs were analyzed 

for every analytical batch to demonstrate the ability of the laboratory to detect similar 

concentrations of a known quantity in matrix-free media. The LCS/LCSD samples were within the 

project established precision limits presented in the QAPP Addendum (AECOM, 2021a). 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 4-4

MS/MS duplicate (MSD) samples were prepared, analyzed, and reported for all preparation 

batches. MS/MSD samples demonstrated that the analytical system was in control for the matrix 

being tested with limited exceptions. MS/MSD samples were submitted to the laboratory for 

analysis at a rate of 5%. One MS/MSD displayed an RPD greater than the QC limit of 20% for 

total organic carbon (TOC) at 26%. The parent sample result associated with the MS/MSD 

imprecision was qualified as an estimate value and should be considered usable as qualified.

Field duplicate samples were collected at a rate of 10% to assess the overall sampling and 

measurement precision for this sampling effort. The field duplicate samples were analyzed for 

PFAS and general chemistry parameters. A parent sample displayed a non-detect result for PFOA 

while the associated field sample duplicate displayed a positive result. The non-detect parent 

sample was qualified “UJ”, while the positive duplicate sample was qualified “J”. The parent and 

duplicate sample results should be considered usable as qualified as estimated values, the 

positive value was used to provide the most conservative value for this location.

4.6.2 Accuracy

Accuracy is a measure of confidence in a measurement. The smaller the difference between the 

measurement of a parameter and its "true" or expected value, the more accurate the 

measurement. The more precise or reproducible the result, the more reliable or accurate the 

result. Accuracy is measured through percent recoveries in the LCS/LCSD, MS/MSD, and 

surrogates.

LCS/LCSD samples were prepared by addition of known concentrations of each analyte in a 

matrix free media known to be free of target analytes. LCS/LCSD samples were analyzed for 

every analytical batch and demonstrated that the analytical system was in control during sample 

preparation and analysis. The LCS/LCSD samples were within the project established accuracy 

limits presented in the QAPP Addendum (AECOM, 2021a). 

MS/MSD samples were prepared, analyzed, and reported at a rate of 5%. MS/MSD samples 

demonstrated that the analytical system was in control for the matrix being tested, with one 

exception. One parent sample displayed MS/MSD percent recoveries greater than the upper QC 

limit of 136% for PFOS at 381% in the MS and 465% in the MSD. The native soil sample result 

was greater than 4 times the spike concentration; no data qualifying action was required and the 

associated field sample result should be considered usable as reported. 

Calibration verifications were performed routinely to ensure that instrument responses for all 

calibrated analytes were within established QC criteria. The calibration verifications performed 

during the laboratory analyses were within the project established precision limits presented in 

the QAPP Addendum (AECOM, 2021a), with limited exceptions. Two calibration verifications 

displayed a percent recovery slightly above the upper QC limit of 130% for perfluorotetradecanoic 

acid (PFTeDA) at 131% in one and PFBS at 136% in the other. PFTeDA and PFBS were not target 

analytes in the associated analytical batches; no data qualifying action was required. 

4.6.3 Representativeness

Representativeness qualitatively expresses the degree to which data accurately reflect site 

conditions. Factors that affect the representativeness of analytical data include appropriate 

sample population definitions, proper sample collection and preservation techniques, analytical 

holding times, use of standard analytical methods, and determination of matrix or analyte 

interferences. 

The laboratory followed the standard analytical techniques “PFAS by liquid chromatography with 

tandem mass spectrometry (LC/MS/MS) Compliant with QSM 5.3 Table B-15.” The method 

includes preparation requirements (i.e. ENVI-Carb or equivalent), mass calibration, spectra, 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 4-5

monitoring ion transitions, standards for both branch and linear isomers as available, and 

isotopically labeled standards.

Field QC samples were collected to assess the representativeness of the data collected. The 

laboratory met the field QC sample collection frequency: field duplicates were collected at a rate 

of 10% for all field samples and MS/MSD samples were collected at a rate of 5%. All preservation 

techniques were followed by the field staff, and all technical and analytical holding times were met 

by the laboratory. The laboratory used approved standard methods in accordance with the QAPP 

Addendum (AECOM, 2021a) for all analyses.

Blanks are collected to ensure the positive results are representative of site conditions instead of 

introduced by the sampling or analytical processes. Equipment blanks and field blanks were 

negative controls collected in the field to assess if cross-contamination was introduced during 

decontamination or ambient conditions. Equipment blanks and field blanks were also collected 

for groundwater and soil samples. Several equipment and field blanks displayed detections of 

multiple target analytes greater than the detection limit. The associated field sample results were 

either non-detect or displayed concentrations greater than 5X the blank detection. No data 

qualifying action was required and the associated field sample results should be considered 

usable as reported.

Laboratory blanks were prepared and analyzed as negative controls to assess if crosscontamination was introduced at the preparation (method blanks) or analytical (Instrument blanks) 

steps. Several instrument blanks displayed detections of multiple target analytes greater than the 

detection limit. The associated field sample results were either non-detect or displayed 

concentrations greater than 5X the blank detection. No data qualifying action was required and 

the associated field sample results should be considered usable as reported.

Field samples were extracted and analyzed within the appropriate holding time in order to 

qualitatively express the degree to which data accurately reflect site conditions with limited 

exceptions. The holding time for pH analysis is “immediate”; all field samples analyzed for pH 

were qualified “J” and should be considered usable as estimated values.

Overall, the data are usable for evaluating the presence or absence of PFAS at the facility. 

Sufficient usable data were obtained to meet the objectives of the SI. 

4.6.4 Comparability

Comparability is the extent to which data from one study can be compared directly to either past 

data from the current project or data from another study. Using standardized sampling and 

analytical methods, units of reporting, and site selection procedures help ensure comparability. 

Standard field sampling and typical laboratory protocols were used during the SI and are 

considered comparable to ongoing investigations.

4.6.5 Completeness

Completeness is a measure of the amount of valid data obtained from a measurement system 

compared to the amount of data expected under normal conditions. The laboratory provided data 

meeting system QC acceptance criteria for all samples tested. Project completeness was 

determined by evaluating the planned versus actual quantities of data. Percent completeness per 

parameter is as follows and reflects the exclusion of ‘X”-flagged data, if applicable: 

• PFAS in groundwater by USEPA Method 537 Modified at 100%

• PFAS in soil by USEPA Method 537 Modified at 100%

• pH in soil by USEPA Method 9045D at 100%
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 4-6

• TOC by USEPA Method 9060 at 100%

4.6.6 Sensitivity

Sensitivity is the capability of a test method or instrument to discriminate between measurement 

responses representing different levels (e.g., concentrations) of a variable of interest. Examples 

of QC measures for determining sensitivity include laboratory fortified blanks, an MDL study, and 

calibration standards at the limit of quantitation (LOQ). In order to meet the needs of the data 

users, project data must meet the measurement performance criteria for sensitivity and project 

LOQs specified in the QAPP Addendum (AECOM, 2021a). The laboratory provided the requested 

MDL studies and provided applicable calibration standards at the LOQ. In order to achieve the 

DQOs for sensitivity outlined in the QAPP Addendum (AECOM, 2021a), the laboratory reported 

all field sample results at the lowest possible dilution. Additionally, any analytes detected below 

the LOQ and above the MDL were reported and qualified “J” as estimated values by the laboratory. 

Several instrument calibration sensitivity checks recovered outside the QC limits for multiple 

target analytes. Re-extraction and reanalysis were not necessary, as the affected analytes were 

not reported in the associated batches; no data qualifying action was required.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 5-1

5. Site Inspection Activities

This section describes the environmental investigation and sampling activities for the SI. The SI 

sampling approach was based on the findings of the PA and implemented in accordance with the 

following approved documents: 

• Final Preliminary Assessment Report, Papago Park Military Reservation, Phoenix, Arizona

dated September 2020 (AECOM, 2020); 

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

dated March 2018 (AECOM, 2018a); 

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

Papago Park Military Reservation, Phoenix, Arizona dated March 2021 (AECOM, 2021a); 

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

• Final Site Safety and Health Plan, Papago Park Military Reservation, Phoenix, Arizona

dated April 2021 (AECOM, 2021b). 

SI field activities were conducted from 19 April to 22 April 2021 and consisted of utility clearance, 

surface soil sampling, and low-flow groundwater sampling. Field activities were conducted in 

accordance with the SI QAPP Addendum (AECOM, 2021a), except as noted in Section 5.7. 

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

LC/MS/MS compliant with QSM 5.3 Table B-15 to fulfill the project DQOs:

• 18 soil grab samples from 18 boring locations; and

• Four groundwater samples from four permanent monitoring well locations. 

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, and investigation-derived waste 

(IDW) polygons are provided in Appendix B3. 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 USACE TPP Process, Engineer Manual (EM) 200-1-2 (USACE, 2016) defines four phases 

to project planning: 1.) defining the project phase; 2.) determining data needs; 3.) developing data 

collection strategies; and 4.) finalizing the data collection plan. The process encourages 

stakeholder involvement in the SI, beginning with defining overall project objectives, including 

quantitative and qualitative DQOs, and formulating a sampling approach to address the AOIs 

identified in the PA. 

A combined TPP Meeting 1 and 2 was held on 19 January 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, AZARNG, USACE, and ADEQ. Stakeholders were 

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

Papago Park Military Reservation, Arizona 

AECOM 5-2

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 TBD after the field event to discuss the results of the SI. Meeting 

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

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

5.1.2 Utility Clearance

AECOM contacted Arizona 811, the local one-call utility location system to notify them of intrusive 

work on 13 April 2021. Additionally, AECOM contracted Ground Penetrating Radar Systems 

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

clearance of the proposed boring locations on 19 April 2021 with input from the AECOM field 

team, ARNG, AZARNG, and ADEQ. General locating services and ground-penetrating radar were 

used to complete the clearance.

5.1.3 Source Water and PFAS Sampling Equipment Acceptability

Since mechanized drilling was not part of the SI scope, a potable water source used for 

decontamination of drilling equipment was not collected at PPMR. Instead, American Society for 

Testing and Materials (ASTM) Type II water, provided by Grainger, was used to decontaminate 

dedicated sampling equipment during the field activities.

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

PFAS sampling environment. The checklist of acceptable materials for use in the PFAS 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 PFAS 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 hand auger in accordance with the SI QAPP Addendum (AECOM, 

2021a). The soil boring locations are shown on Figure 5-1 and depths are provided Table 5-1. 

Eighteen surface soil samples were collected from 0 to 2 feet bgs. Where refusal was encountered 

before reaching the target depth of 2 feet bgs, one additional attempt was made adjacent to the 

original location (within 10 feet of the original boring) to collect a soil sample from the proposed 

depth. Hand auger borings were abandoned by backfilling with native soil. Prior to collection in 

lab-provided bottleware, soil was placed in a Ziplock bag for characterization and homogenization.

The recovered soil was logged for lithological descriptions by a field geologist using the Unified 

Soil Classification System (USCS). A photoionization detector (PID) was used to screen the 

breathing zone during boring activities as part of personal safety requirements. Observations and 

measurements were recorded on boring logs and in a non-treated field logbook (i.e., composition 

notebook). Depth interval, recovery thickness, PID concentrations, moisture, relative density, 

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

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 for PFAS (LC/MS/MS compliant with QSM 5.3 Table B-15), TOC 

(USEPA Method 9060A) and pH (USEPA Method 9045D) in accordance with the SI QAPP 

Addendum (AECOM, 2021a). 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 5-3

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 

(ERBs) 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.

5.3 Groundwater Sampling

Due to the complex hydrogeology at PPMR, no temporary or permanent monitoring wells were 

installed as part of the SI. Instead, four existing monitoring wells were selected to be sampled

based on their downgradient location to suspected release areas. Target depth of these wells is 

the surficial aquifer within fractured bedrock. The screen interval of each of the groundwater 

monitoring wells is provided in Table 5-2 and well locations are shown on Figure 5-1. 

Sampling of the existing groundwater monitoring wells was completed in accordance with the SI 

QAPP Addendum (AECOM, 2021a). Groundwater samples were collected via low-flow sampling 

methods using a peristaltic pump with disposable PFAS-free, HDPE tubing. 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, oxidation-reduction 

potential, and turbidity) 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 PFAS by LC/MS/MS compliant with 

QSM 5.3 Table B-15 in accordance with the SI QAPP Addendum (AECOM, 2021a). 

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

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

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

accordance with the Programmatic QAPP (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 20 April 2021. Groundwater elevation 

measurements were collected from the four existing monitoring wells sampled. Water level 

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

map was drafted using groundwater elevations calculated from existing survey data and the 

synoptic gauging data; however, the limited number and spatial coverage of the monitoring wells

gauged did not provide a representative understanding of groundwater flow across the area. As 

a result, no groundwater contour map is included in this SI Report. The calculated groundwater 

elevation data is provided in Table 5-2. 

5.5 Investigation-Derived Waste

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

generated during the SI is considered non-hazardous waste and was managed in accordance 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 5-4

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 left in place at the point of the 

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

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

soil samples collected from that source location. 

Liquid IDW generated during SI activities (i.e. purge water and decontamination fluids) was 

containerized in a 55-gallon drum and stored in the air sparging system compound at the facility. 

The liquid IDW was not sampled and assumes the PFAS characteristics of the associated 

groundwater samples collected from that source location. The containerized IDW will be 

temporarily stored at the facility until the analytical results for the associated groundwater samples 

are available. ARNG will manage and dispose of the liquid IDW 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). 

ARNG will further coordinate with the ADEQ to ensure proper disposal is in accordance with any 

state requirements and the Army Guidance for Addressing Releases of PFAS, Q18 (DA, 2018). 

Geographic coordinates were collected using a global positioning system around each location 

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

in Appendix B3. 

Other solids, such as spent PPE, plastic sheeting, tubing, rope, unused monitoring well 

construction materials, and other environmental media generated during the field activities, were 

disposed of at a licensed solid waste landfill.

5.6 Laboratory Analytical Methods

Samples were analyzed for a subset of 18 PFAS by LC/MS/MS compliant with QSM 5.3 Table B15 at Pace Analytical Gulf Coast in Baton Rouge, Louisiana, a DoD ELAP and NELAP certified 

laboratory. The 18 PFAS analyzed as part of the ARNG SI program include the following: 

• 6:2 fluorotelomer sulfonic acid (6:2 FTS)

• 8:2 fluorotelomer sulfonic acid (8:2 FTS)

• N-ethyl 

perfluorooctanesulfonamidoacetic acid 

(NEtFOSAA) 

• N-methyl 

perfluorooctanesulfonamidoacetic acid 

(NMeFOSAA) 

• Perfluorobutyrate (PFBA) 

• Perfluorobutanesulfonic acid (PFBS)

• Perfluorodecanoic acid (PFDA)

• Perfluorododecanoic acid (PFDoA)

• Perfluoroheptanoic acid (PFHpA)

• Perfluorohexanoic acid (PFHxA)

• Perfluorohexanesulfonic acid (PFHxS)

• Perfluorononanoic acid (PFNA)

• Perfluorooctanoic acid (PFOA)

• Perfluorooctanesulfonic acid (PFOS)

• Perfluoropentanoic acid (PFPeA)

• PFTeDA

• Perfluorotridecanoic acid (PFTrDA)

• Perfluoroundecanoic acid (PFUdA)

Soil samples were also analyzed for TOC using USEPA Method 9060A and pH by USEPA Method 

9045D. 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 5-5

5.7 Deviations from SI QAPP Addendum

Deviations from the SI QAPP Addendum occurred based on field conditions and discussion 

between AECOM, ARNG, and USACE. Deviations from the SI QAPP Addendum are noted below

and are documented in the Field Change Request Forms (Appendix B4): 

• During the site walk conducted on 19 April 2021 with the client and ADEQ, the team agreed 

to relocate AOI01-13 from its proposed location to an open lot adjacent to the ‘Mobile Fire 

Extinguisher’ potential release area. USACE was informed of the proposed change and 

agreed via email on 19 April 2021. This action was documented in a Field Change Request 

form provided in Appendix B4. 

• During surface soil sampling, refusal was encountered before reaching the target depth of 

2 feet bgs at 16 of 18 boring locations. Upon encountering refusal, one additional attempt to 

reach the desired depth was made within 10 feet of the original boring location. In each 

instance, refusal was encountered due to challenging soil conditions (presences of large 

cobbles and/or shallow bedrock).

• The soil and groundwater SLs for PFBS in this document has been updated since the Final 

SI QAPP due to a change in the OSD Memo (dated 15 September 2021). The revised SLs 

were developed using the USEPA Regional Screening Levels (RSLs) Calculator and are 

considered valid toxicity based values after peer review. 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 5-6

THIS PAGE INTENTIONALLY BLANK
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, 

Papago Park Military Reserve, Phoenix, Arizona

Sample Identification

Sample

Collection 

Date/Time

Sample Depth 

(feet bgs)

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

Comments

AOI01-01-SB-0-1 4/21/2021 10:50 1 x

AOI01-02-SB-0-0.5 4/21/2021 10:25 0.5 x

AOI01-03-SB-0-1 4/21/2021 9:50 1 x x x

AOI01-03-SB-0-1-D 4/21/2021 9:50 1 x x x Field Duplicate

AOI01-03-SB-0-1-MS 4/21/2021 9:50 1 x x x MS/MSD

AOI01-03-SB-0-1-MSD 4/21/2021 9:50 1 x x x MS/MSD

AOI01-04-SB-0-0.5 4/21/2021 9:15 0.5 x

AOI01-04-SB-0-0.5-D 4/21/2021 9:15 0.5 x Field Duplicate

AOI01-05-SB-0-0.75 4/21/2021 9:03 0.75 x

AOI01-06-SB-0-0.75 4/21/2021 8:20 0.75 x

AOI01-07-SB-0-2 4/22/2021 9:15 2 x

AOI01-08-SB-0-1.25 4/22/2021 8:10 1.25 x

AOI01-09-SB-0-0.25 4/22/2021 8:32 0.25 x

AOI01-10-SB-0-1.7 4/22/2021 7:30 1.7 x

AOI01-10-SB-0-1.7-D 4/22/2021 7:30 1.7 x Field Duplicate

AOI01-11-SB-0-0.5 4/22/2021 12:20 0.5 x

AOI01-12-SB-0-0.5 4/22/2021 12:38 0.5 x

AOI01-13-SB-0-2 4/21/2021 7:50 2 x

AOI01-13-SB-0-2-MS 4/21/2021 7:50 2 x MS/MSD

AOI01-13-SB-0-2-MSD 4/21/2021 7:50 2 x MS/MSD

AOI01-14-SB-0-1 4/21/2021 13:05 1 x

AOI01-15-SB-0-1.9 4/21/2021 13:40 1.9 x

AOI01-16-SB-0-0.75 4/22/2021 9:45 0.75 x

AOI01-17-SB-0-0.58 4/22/2021 9:58 0.58 x

AOI01-18-SB-0-1.25 4/22/2021 10:28 1.25 x

MW-23-042021 4/20/2021 9:50 26 x

MW-23-042021-MS 4/20/2021 9:50 26 x MS/MSD

MW-23-042021-MSD 4/20/2021 9:50 26 x MS/MSD

MW-24-042021 4/20/2021 10:30 25 x

MW-25-042021 4/20/2021 11:25 27 x

MW-26-042021 4/20/2021 11:10 28 x

MW-26-042021-D 4/20/2021 11:10 28 x Field Duplicate

PPMR-FRB-01 4/20/2021 11:50 --- x Field Blank

PPMR-ERB-01 4/20/2021 12:35 --- x Equipment Blank

PPMR-ERB-02 4/21/2021 14:00 --- x Equipment Blank

PPMR-ERB-03 4/22/2021 10:55 --- x Equipment Blank

Notes:

bgs = below ground surface

ERB = equipment rinsate blank

D = field duplicate

FRB = field reagent blank

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MS/MSD = matrix spike/ matrix spike duplicate

PFAS = per- and polyfluoroalkyl substances

QSM = Quality Systems Manual

TOC = total organic carbon

USEPA = United States Environmental Protection Agency

Groundwater Samples

Soil Samples

Blank Samples

AECOM 5-7
Site Inspection Report

Papago Park Military Reservation, Arizona 

THIS PAGE INTENTIONALLY BLANK

AECOM 5-8
Table 5-2

Soil Boring Depths, Well Screen Intervals, and Groundwater Elevations

Site Inspection Report

Papago Park Military Reservation, Phoenix, Arizona

Area of

Interest

Boring

Location

Soil Boring Depth

(feet bgs)

Well Screen

Interval

(feet bgs)

Top of Casing

Elevation

(feet NAVD88)

Ground Surface

Elevation

(feet NAVD88)

Depth to Water

(feet btoc)

Depth to Water

(feet bgs)

Groundwater

Elevation

(feet NAVD88)

AOI01-01 1 NA NA NA NA NA NA

AOI01-02 0.5 NA NA NA NA NA NA

AOI01-03 1 NA NA NA NA NA NA

AOI01-04 0.5 NA NA NA NA NA NA

AOI01-05 0.75 NA NA NA NA NA NA

AOI01-06 0.75 NA NA NA NA NA NA

AOI01-07 2 NA NA NA NA NA NA

AOI01-08 1.25 NA NA NA NA NA NA

AOI01-09 0.25 NA NA NA NA NA NA

AOI01-10 1.7 NA NA NA NA NA NA

AOI01-11 0.5 NA NA NA NA NA NA

AOI01-12 0.5 NA NA NA NA NA NA

AOI01-13 2 NA NA NA NA NA NA

AOI01-14 1 NA NA NA NA NA NA

AOI01-15 1.9 NA NA NA NA NA NA

AOI01-16 0.75 NA NA NA NA NA NA

AOI01-17 0.58 NA NA NA NA NA NA

AOI01-18 1.25 NA NA NA NA NA NA

MW-23 35.5 8-35.5 1234.94 NA 17.54 NA 1217.40

MW-24 35.5 8-35.5 1236.27 NA 14.41 NA 1221.86

MW-25 35 10-35 1235.53 NA 19.14 NA 1216.39

MW-26 35 7.5-35 1235.76 NA 20.71 NA 1215.05

Notes:

1

Total well depth not measured during groundwater sampling to avoid interference with the air sparging system. Well depths based on bottom of well screen interval.

bgs = below ground surface

btoc = below top of casing

NA = not applicable

NAVD88 = North American Vertical Datum 1988

1

AECOM 5-9
AECOM 5-10

Site Inspection Report

Papago Park Military Reservation, Arizona 

THIS PAGE INTENTIONALLY BLANK
"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S

"S "S

A!

A!

A!

A!

Stormwater Retention Basin

Sediment Trap

Culvert SW of 5201

Culvert SE of 5201

Building M5201 Exterior

Building M5201

Mobile Fire Extinguishers

AOI01-01

AOI01-02

AOI01-03

AOI01-04

AOI01-05

AOI01-06

AOI01-07

AOI01-08

AOI01-09

AOI01-10

AOI01-11

AOI01-12

AOI01-13

AOI01-14

AOI01-15

AOI01-16

AOI01-17 AOI01-18

MW-23

MW-24

MW-25

MW-26

AOI 1

0 125 250 500

Feet

­ Figure 5-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Papago Park Military Res, AZ

5/3/2021

5/3/2021

5/3/2021

MS

AB

CM

GIS BY

CHK BY

PM

Base Map: Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS,

USDA, USGS, AeroGRID, IGN, and the GIS User Community

5/3/2021

1:3,000

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Fig_5-1_Papago_SI_Sample_Locations.mxd

"S Hand Auger Surface Soil Sample

A! Existing Monitoring Well

Area of Interest

Potential PFAS Release

Facility Boundary

Site Inspection Sample Locations

12420 Milestone Center Drive

Germantown, MD 20876

M5228

M5204

AECOM 5-11
AECOM 5-12

Site Inspection Report

Papago Park Military Reservation, Arizona 

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Papago Park Military Reservation, Arizona 

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 AOI 1 is provided in Sections 6.2 and

6.3. Table 6-2 and Table 6-3 present PFAS results for samples with detections in soil or 

groundwater; only constituents detected in one or more samples are included. 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 15 September

2021 (Assistant Secretary of Defense, 2021). 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 three compounds: 

PFOS, PFOA, and PFBS. 

The SLs apply to three compounds, PFOA, PFOS, and PFBS, for both soil and groundwater, as 

presented in Table 6-1. All other results presented in this report are considered informational in 

nature and serve as an indication as to whether soil and groundwater contain or do not contain 

PFAS within the boundaries of the facility. 

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

Analyte

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 130 1,600 40

PFOS 130 1,600 40

PFBS 1,900 25,000 600

Notes:

a.) Assistant Secretary of Defense, 2021. Risk Based Screening Levels Calculated for PFOS, PFOA, PFBS in Groundwater and Soil using 

United States Environmental Protection Agency’s (USEPA’s) Regional Screening Level Calculator. Hazard Quotient (HQ) = 0.1. 15

September 2021. 

6.2 Soil Physicochemical Analyses

One soil sample was collected for TOC and pH analysis, which can be important for evaluating 

contaminant transport through the soil medium. The pH result was 8.46 and the TOC was 5,730 

milligram per kilogram (mg/Kg). Appendix F contains the results of the TOC and pH sampling. 

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

appropriate, to assess fate and transport of PFAS contaminants. According to the Interstate 

Technology Regulatory Council (ITRC), several important PFAS 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 they 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 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 6-2

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, which includes four potential PFAS release areas: the Former Fire Truck Bay ( M5201), Runway

(M5228) and Rotary Wing Parking Apron (M5204), AFFF Storage Area ( M5201 Exterior), and the 

Mobile Fire Extinguishers Area. The detected compounds in soil and groundwater are 

summarized on Table 6-2 and Table 6-3. The detections of PFOA, PFOS, and PFBS in soil and 

groundwater are presented on Figure 6-1 through Figure 6-4. 

6.3.1 AOI 1 Soil Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in soil at any of the four potential PFAS release 

areas. Figure 6-1 through Figure 6-3 present the ranges of detections of PFOA, PFOS, and 

PFBS in soil. Table 6-2 summarize the detected compounds in soil. 

Along the Runway (M5228) and Rotary Wing Parking Apron (M5204), soil was sampled from 

surface soil (depths ranged from 0 to 0.5 feet bgs to 0 to 1 ft bgs) boring locations AOI01-1 through

AOI01-06. PFOA, PFOS, and PFBS were detected in soil at concentrations several orders of 

magnitude lower than the SLs. PFOA was detected at all six boring locations at concentrations 

ranging from 0.062 J micrograms per kilogram (μg/kg) to 1.51 μg/kg. PFOS was detected at all 

six boring locations at concentrations ranging from 4.32 μg/kg to 24.1 μg/kg. PFBS was detected 

at locations AOI01-04, AOI01-05, and AOI01-06 at concentrations ranging from 0.074 J μg/kg 

(0.072 J μg/kg duplicate result) to 0.171 J μg/kg. 

At the Mobile Fire Extinguisher Area, soil was sampled from surface soil (0 to 2 feet bgs) boring 

location AOI01-13. PFOA and PFOS were detected at concentrations of 0.464 J μg/kg and 26.1 

J μg/kg, respectively. PFBS was not detected at location AOI01-13. 

The Former Fire Truck Bay ( M5201) and AFFF Storage Area ( M5201 Exterior) potential release 

areas are covered by hard surface (asphalt and concrete). Therefore, per the QAPP Addendum, 

hand auger surface soil boring locations were positioned downgradient of the potential release 

areas in unpaved areas and included: AOI01-07 through AOI01-12 and AOI01-14 through AOI01-

18. Samples -16, -17, and -18 were collected from a dry retention pond downstream and across 

the street from the potential release area. PFOA was detected at nine boring locations at

concentrations ranging from 0.070 J μg/kg to 0.604 J μg/kg. PFOS was detected at ten boring

locations at concentrations ranging from 0.203 J μg/kg to 20.0 μg/kg. PFBS was detected at three 

boring locations at concentrations ranging from 0.056 J μg/kg to 0.231 J μg/kg.

6.3.2 AOI 1 Groundwater Analytical Results

PFOA and PFOS in groundwater exceeded the SLs at the existing monitoring wells downgradient 

of AOI 1. PFBS did not exceed the SL at any of the existing monitoring wells downgradient of AOI 

1. Figure 6-4 presents the ranges of detections of PFOA, PFOS, and PFBS in groundwater. Table 

6-3 summarizes the detected compounds in groundwater.

Four existing monitoring wells were sampled downgradient of AOI 1. PFOA was detected at all 

four locations and exceeded the SL of 40 ng/L at three locations, with concentrations ranging from 

20.9 ng/L to 292 ng/L. Similarly, PFOS was detected at all four locations and exceeded the SL of 

40 ng/L at three locations with concentrations ranging from 3.36 J ng/L to 166 ng/L (170 ng/L 

duplicate). PFBS was detected at all four locations, but it did not exceed the SL. Concentrations 

ranged from 22.1 J ng/L to 249 ng/L.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 6-3

6.3.3 AOI 1 Conclusions

Based on the results of the SI, PFOA, PFOS, and PFBS were detected in soil at AOI 1; however, 

the detected concentrations were several orders of magnitude lower than the soil SLs. At the 

existing monitoring wells downgradient of the potential PFAS release areas, PFOS and PFOA 

were detected in groundwater at concentrations exceeding the individual SLs of 40 ng/L. PFBS 

was detected in groundwater at concentrations below the SL. Based on the exceedances of the 

SLs for PFOA and PFOS in groundwater, further evaluation at AOI 1 is warranted. 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 6-4

THIS PAGE INTENTIONALLY BLANK
Table 6-2

PFAS Detections in Surface Soil

Site Inspection Report, Papago Park Military Reservation

Analyte OSD Screening 

Level a,b

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

PFBA - ND 0.079 J ND ND ND ND 0.285 J 0.089 J ND 0.170 J

PFBS 1900 ND ND ND 0.074 J 0.072 J 0.098 J 0.171 J ND 0.056 J ND

PFDA - 0.176 J 0.133 J 0.538 J 0.230 J 0.216 J 0.104 J 0.279 J ND ND 0.081 J

PFDoA - ND ND 0.246 J 0.409 J 0.379 J ND ND ND ND ND

PFHpA - ND ND ND ND ND ND ND 0.131 J ND ND

PFHxA - ND 0.042 J 0.049 J 0.087 J 0.078 J 0.275 J 0.156 J 0.206 J 0.243 J 0.169 J

PFHxS - ND ND 0.278 J 0.517 J 0.490 J 1.29 0.399 J 3.09 0.423 J 0.265 J

PFNA - 0.135 J 0.151 J 0.211 J ND ND 0.162 J 0.179 J 0.070 J ND 0.233 J

PFOA 130 0.108 J 0.076 J 0.132 J ND UJ 0.062 J 1.51 0.256 J 0.460 J 0.070 J 0.571 J

PFOS 130 9.32 4.32 14.5 4.98 5.22 24.1 5.93 20.0 ND 8.22

PFPeA - ND ND ND 0.399 J 0.353 J 0.171 J 0.124 J ND ND 0.062 J

PFTeDA - ND ND ND 0.142 J 0.135 J ND ND ND ND ND

PFTrDA - ND ND ND 0.146 J 0.142 J ND ND ND ND ND

PFUnDA - 0.017 J 0.020 J 0.227 J 0.280 J 0.265 J 0.021 J 0.052 J ND ND 0.015 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBA perfluorobutanoic acid

PFBS perfluorobutanesulfonic acid

PFDA perfluorodecanoic acid

References PFDoA perfluorododecanoic acid

PFHpA perfluoroheptanoic acid

PFHxA perfluorohexanoic acid

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PFPeA perfluoropentanoic acid

Interpreted Qualifiers PFTeDA perfluorotetradecanoic acid

J = Estimated concentration PFTrDA perfluorotridecanoic acid

UJ = The analyte was not detected at a level greater than or equal to the adjusted detection limit (DL). However, the reported adjusted DL is approximate and may be inaccurate or imprecise. PFUnDA perfluoro-n-undecanoic acid

Acronyms and Abbreviations

AOI Area of Interest

D Duplicate

ft feet

HQ Hazard quotient

LCMSMS Liquid Chromatography Mass Spectrometry

LOD Limit of Detection

ND Analyte not detected above the LOD

OSD Office of the Secretary of Defense

PFAS per- and polyfluoroalkyl substances

QSM Quality Systems Manual

Qual Interpreted Qualifier

SB Soil boring

USEPA United States Environmental Protection Agency

ug/Kg micrograms per Kilogram

- Not applicable

a. Assistant Secretary of Defense, 2019. Risk Based Screening Levels Calculated for PFOS and PFOA in Groundwater or Soil using USEPA’s Regional Screening Level

Calculator. HQ=0.1. 15 October 2019. Soil screening levels based on residential scenario for direct ingestion of contaminated soil.

AOI01

b. USEPA, 2021. Risk Based Screening Levels Calculated for PFBS in Groundwater and Soil using USEPA's Regional Screening Level Calculator. HQ=0.1. 8 April 2021.

AOI01-09-SB-0-0.25

04/22/2021

0 - 0.25 ft

Soil, PFAS by LCMSMS Compliant with QSM 5.3 Table B-15 (ug/Kg)

AOI01-07-SB-0-2

04/22/2021

0 - 2 ft

AOI01-08-SB-0-1.25

04/22/2021

0 - 1.25 ft

AOI01-05-SB-0-0.75

04/21/2021

0 - 0.75 ft

AOI01-06-SB-0-0.75

04/21/2021

0 - 0.75 ft

AOI01-04-SB-0-0.5

04/21/2021

0 - 0.5 ft

AOI01-04-SB-0-0.5-D

04/21/2021

0 - 0.5 ft

AOI01-02-SB-0-0.5

04/21/2021

0 - 0.5 ft

AOI01-03-SB-0-1

04/21/2021

0 - 1 ft

Area of Interest

Sample ID

Sample Date

Depth

AOI01-01-SB-0-1

04/21/2021

0 - 1 ft

AECOM 6-5
Table 6-2

PFAS Detections in Surface Soil

Site Inspection Report, Papago Park Military Reservation

Analyte OSD Screening 

Level a,b

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

PFBA - 0.088 J 0.079 J 0.090 J ND 0.115 J ND 0.168 J ND 0.088 J ND

PFBS 1900 ND ND 0.093 J ND ND ND ND ND ND 0.231 J

PFDA - ND ND 0.048 J ND 0.116 J 0.092 J 0.168 J 0.049 J ND 0.358 J

PFDoA - ND ND ND ND ND ND ND 0.104 J ND 0.446 J

PFHpA - ND ND ND 0.108 J ND ND ND ND ND ND

PFHxA - 0.155 J 0.123 J 0.152 J 0.074 J 0.106 J ND ND ND 0.069 J 0.105 J

PFHxS - 0.172 J 0.132 J ND 1.02 0.857 J ND ND ND 0.493 J 0.385 J

PFNA - ND ND ND 0.073 J 0.337 J ND 0.124 J ND ND ND

PFOA 130 0.324 J 0.245 J 0.179 J 0.604 J 0.464 J ND 0.155 J ND 0.366 J 0.105 J

PFOS 130 0.779 J 0.581 J 0.271 J 1.20 26.1 J 0.660 J 1.05 0.203 J 0.292 J 3.47

PFPeA - ND ND 0.080 J ND 0.140 J ND ND ND ND ND

PFTeDA - ND ND ND ND ND ND ND ND ND ND

PFTrDA - ND ND ND ND ND ND ND ND ND ND

PFUnDA - ND ND ND ND 0.015 J 0.056 J 0.033 J 0.038 J ND 0.350 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBA perfluorobutanoic acid

PFBS perfluorobutanesulfonic acid

PFDA perfluorodecanoic acid

References PFDoA perfluorododecanoic acid

PFHpA perfluoroheptanoic acid

PFHxA perfluorohexanoic acid

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PFPeA perfluoropentanoic acid

Interpreted Qualifiers PFTeDA perfluorotetradecanoic acid

J = Estimated concentration PFTrDA perfluorotridecanoic acid

UJ = The analyte was not detected at a level greater than or equal to the adjusted detection limit (DL). However, the reported adjusted DL is approximate and may be inaccurate or imprecise. PFUnDA perfluoro-n-undecanoic acid

Acronyms and Abbreviations

AOI Area of Interest

D Duplicate

ft feet

HQ Hazard quotient

LCMSMS Liquid Chromatography Mass Spectrometry

LOD Limit of Detection

ND Analyte not detected above the LOD

OSD Office of the Secretary of Defense

QSM Quality Systems Manual

Qual Interpreted Qualifier

SB Soil boring

USEPA United States Environmental Protection Agency

ug/Kg micrograms per Kilogram

- Not applicable

a. Assistant Secretary of Defense, 2019. Risk Based Screening Levels Calculated for PFOS and PFOA in Groundwater or Soil using USEPA’s Regional Screening Level

Calculator. HQ=0.1. 15 October 2019. Soil screening levels based on residential scenario for direct ingestion of contaminated soil.

AOI01

b. USEPA, 2021. Risk Based Screening Levels Calculated for PFBS in Groundwater and Soil using USEPA's Regional Screening Level Calculator. HQ=0.1. 8 April 2021.

AOI01-18-SB-0-1.25

04/22/2021

0 - 1.25 ft

Soil, PFAS by LCMSMS Compliant with QSM 5.3 Table B-15 (ug/Kg)

AOI01-16-SB-0-0.75

04/22/2021

0 - 0.75 ft

AOI01-17-SB-0-0.58

04/22/2021

0 - 0.58 ft

AOI01-14-SB-0-1

04/21/2021

0 - 1 ft

AOI01-15-SB-0-1.9

04/21/2021

0 - 1.9 ft

AOI01-12-SB-0-0.5

04/21/2021

0 - 0.5 ft

AOI01-13-SB-0-2

04/21/2021

0 - 2 ft

AOI01-10-SB-0-1.7-D

04/22/2021

0 - 1.7 ft

AOI01-11-SB-0-0.5

04/21/2021

0 - 0.5 ft

Area of Interest

Sample ID

Sample Date

Depth

AOI01-10-SB-0-1.7

04/22/2021

0 - 1.7 ft

AECOM 6-6
Table 6-3

PFAS Detections in Groundwater

Site Inspection Report, Papago Park Military Reservation

Analyte OSD Screening 

Level a,b

Result Qual Result Qual Result Qual Result Qual Result Qual

6:2 FTS - ND 20.1 ND ND ND

PFBA - 41.1 49.6 95.6 38.8 40.6

PFBS 600 22.1 J 51.6 249 53.8 55.6

PFHpA - 35.1 J 29.8 246 44.5 46.9

PFHxA - 58.5 61.8 1900 123 125

PFHxS - 31.7 J 178 4430 683 659

PFNA - ND ND ND 1.75 J 1.89 J

PFOA 40 65.1 20.9 292 77.2 79.6

PFOS 40 124 101 3.36 J 166 170

PFPeA - 26.2 J 42.4 286 57.1 59.0

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

6:2 FTS 6:2 fluorotelomer sulfonate

PFBA perfluorobutanoic acid

References PFBS perfluorobutanesulfonic acid

PFHpA perfluoroheptanoic acid

PFHxA perfluorohexanoic acid

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PFPeA perfluoropentanoic acid

Interpreted Qualifiers

J = Estimated concentration Acronyms and Abbreviations

AOI Area of Interest

D Duplicate

GW Groundwater

HA Health advisory

HQ Hazard quotient

LCMSMS Liquid Chromatography Mass Spectrometry

LOD Limit of Detection

ND Analyte not detected above the LOD

OSD Office of the Secretary of Defense

PFAS per- and polyfluoroalkyl substances

QSM Quality Systems Manual

Qual Interpreted Qualifier

USEPA United States Environmental Protection Agency

ng/L nanogram per liter

- Not applicable

Area of Interest

Sample ID

Sample Date

MW-23-042021

04/20/2021

AOI01

MW-24-042021

04/20/2021

MW-25-042021

04/20/2021

Water, PFAS by LCMSMS Compliant with QSM 5.3 Table B-15 (ng/L)

a. Assistant Secretary of Defense, 2019. Risk Based Screening Levels Calculated for PFOS and PFOA in Groundwater or Soil using USEPA’s Regional

Screening Level Calculator. HQ=0.1. 15 October 2019. Groundwater screening levels based on residential scenario for direct ingestion of groundwater.

b. USEPA, 2021. Risk Based Screening Levels Calculated for PFBS in Groundwater and Soil using USEPA's Regional Screening Level Calculator.

HQ=0.1. 8 April 2021.

MW-26-042021

04/20/2021

MW-26-042021-D

04/20/2021

AECOM 6-7
AECOM 6-8

Site Inspection Report

Papago Park Military Reservation, Arizona 

THIS PAGE INTENTIONALLY BLANK
AOI01-01

AOI01-02

AOI01-03

AOI01-04

AOI01-06 AOI01-05

AOI01-07

AOI01-08

AOI01-09

AOI01-10

AOI01-11

AOI01-12

AOI01-13

AOI01-14

AOI01-15

AOI01-16

AOI01-17

AOI01-18

12420 Milestone Center Drive

Germantown, MD 20876 Figure 6-1

PFOA Detections in Surface Soil

8/18/2021

8/18/2021

MS 8/18/2021

AB

CM

GIS BY

CHK BY

PM

8/18/2021

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Papago Park Military Res, AZ

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Results\Fig_6-1_Papago_SI_PFOA_Soil_Results.mxd

Base Map: Source: Esri, Maxar, GeoEye, Earthstar

Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,

1:2,160

0 90 180 360

Feet

Legend

Facility Boundary PFOA Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

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

AECOM 6-9
AOI01-01

AOI01-02

AOI01-03

AOI01-04

AOI01-06 AOI01-05

AOI01-07

AOI01-08

AOI01-09

AOI01-10

AOI01-11

AOI01-12

AOI01-13

AOI01-14

AOI01-15

AOI01-16

AOI01-17

AOI01-18

12420 Milestone Center Drive

Germantown, MD 20876 Figure 6-2

PFOS Detections in Surface Soil

8/18/2021

8/18/2021

MS 8/18/2021

AB

CM

GIS BY

CHK BY

PM

8/18/2021

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Papago Park Military Res, AZ

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Results\Fig_6-2_Papago_SI_PFOS_Soil_Results.mxd

Base Map: Source: Esri, Maxar, GeoEye, Earthstar

Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,

1:2,160

0 90 180 360

Feet

Legend

Facility Boundary PFOS Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

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

AECOM 6-10
AOI01-01

AOI01-02

AOI01-03

AOI01-04

AOI01-06 AOI01-05

AOI01-07

AOI01-08

AOI01-09

AOI01-10

AOI01-11

AOI01-12

AOI01-13

AOI01-14

AOI01-15

AOI01-16

AOI01-17

AOI01-18

12420 Milestone Center Drive

Germantown, MD 20876 Figure 6-3

PFBS Detections in Surface Soil

10/18/2021

10/18/2021

MS 10/18/2021

AB

CM

GIS BY

CHK BY

PM

10/18/2021

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Papago Park Military Res, AZ

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Results\Fig_6-3_Papago_SI_PFBS_Soil_Results.mxd

Base Map: Source: Esri, Maxar, GeoEye, Earthstar

Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,

1:2,160

0 90 180 360

Feet

Legend

Facility Boundary PFBS Results (μg/Kg)

ND

>ND - 10

>10 - 1,900

>1,900 - 25,000

>25,000

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

AECOM 6-11
MW-23

MW-24

MW-25

MW-26

MW-23

MW-24

MW-25

MW-26

MW-23

MW-24

MW-25

MW-26

12420 Milestone Center Drive

Germantown, MD 20876 Figure 6-4

PFOA, PFOS, and PFBS 

Detections in Groundwater

10/18/2021

10/18/2021

MS 10/18/2021

AB

CM

GIS BY

CHK BY

PM

10/18/2021

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Papago Park Military Res, AZ

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\AZ\Papago_Park_MR_Figures\Papago_Park_MR_SI_Figures\SI_Report\Results\Fig_6-4_Papago_SI_PFOA_PFOS_PFBS_GW_Results.mxd

Base Map: Source: Esri, Maxar, GeoEye, Earthstar

Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,

1:1,800

0 75 150 300

Feet

PFOA

PFOS

Legend

Facility Boundary

PFBS

PFOS Results (ng/L)

ND

>ND -10

>10 - 40

>40 - 70

>70 - 400

>400

PFOA Results (ng/L)

ND

>ND - 10

>10 - 40

>40 - 70

>70 - 400

>400

PFBS Results (ng/L)

ND

>ND - 100

>100 - 600

>600 - 1,000

>1,000 - 6,000

>6,000

AECOM 6-12
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 7-1

7. Exposure Pathways

The CSM for AOI 1, revised based on the SI findings, is presented on Figure 7-1. 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 figure uses 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 

PFOA, PFOS, or PFBS 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 

PFOA, PFOS, or PFBS above the SLs. Areas with an identified potentially complete pathway that 

have detections of PFOA, PFOS, or PFBS above the SLs may warrant further investigation. 

In general, the potential routes of exposure to PFAS 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 PFAS 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, residents outside the facility boundary, and recreational users outside of the facility 

boundary. 

7.1 Soil Exposure Pathway

The SI results for PFOA, PFOS, and PFBS in soil were used to determine whether a potentially 

complete pathway exists between the source and potential receptors at the AOI based on the 

aforementioned criteria. 

7.1.1 AOI 1

From the 1970s to the mid-2000s, AFFF was released to soil at four potential PFAS release areas 

within the AOI 1 through fire training, equipment testing, and AFFF storage. PFOA, PFOS, and 

PFBS were detected in soil at AOI 1 and confirm the release of PFAS to soil. 

Based on the results of the SI in AOI 1, ground-disturbing activities could potentially result in site 

worker, construction worker, or recreational user/trespasser exposure to PFOA, PFOS, and PFBS

via inhalation of dust. Off-facility residents may potentially be exposed to PFOA, PFOS, and PFBS 

via inhalation of dust caused by on-facility ground disturbing activities, though this pathway is 

likely insignificant. Ground-disturbing activities could also potentially result in site worker, 

construction worker, and trespasser exposure via ingestion of surface soil. Lasty, grounddisturbing activities could also potentially result in future construction worker exposure to PFOA, 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 7-2

PFOS, and PFBS in subsurface soil via ingestion. No construction was occurring at the time of 

the SI field effort. The CSM is presented on Figure 7-1. 

7.2 Groundwater Exposure Pathway

The SI results for PFOA, PFOS, and PFBS in groundwater were used to determine whether a 

potentially complete pathway exists between the source and potential receptors at the AOI based 

on the aforementioned criteria.

7.2.1 AOI 1

PFOA, PFOS, and PFBS were detected in groundwater collected from four existing monitoring 

wells downgradient of potential release areas and exceeded SLs for PFOA and PFOS. Drinking 

water at the facility is provided by the City of Phoenix and is sourced primarily from the SRP and 

CAP. Furthermore, no potable drinking water wells are located at or downgradient of the facility; 

therefore, the ingestion exposure pathway is incomplete for site workers, off-facility residents, and 

recreational users/trespassers. However, due to the depth to water in the shallow aquifer, the 

ingestion exposure pathway for future construction workers is considered potentially complete

with an exceedance. No construction was occurring at the time of the SI field effort. The CSM is 

presented on Figure 7-1. 
Media

SOURCE PATHWAY RE

AOI 1

Army Aviation

Support Facility #1 

and Vicinity

PFAS in 

Surface Soil

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ Infiltration

Airborne Soil 

particulate

Surface Soil 

at AOI

Surface 

Water/ 

sediment4

Subsurface 

Soil

Groundwater

Source Release Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

Dust

IngestionIngestion

Ingestion

Ingestion

Hum

C

Flow-Chart ContinuesPartial / Possible FlowFlow-Chart StopsIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL

Site 

Worker

Cons

Wo

Site 

Worker

Cons

W

LEGEND

/ / 

Figure 

Conceptual S

Papago Park Military 

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

/ 

/

NOTES1. The resident receptor refers to an offsite resident.2. Inhalation of dust for off-site receptors islikely insignificant.3. No current active construction at PPMR.4. No surface water/sediment featuresexist onsite.

/ 
AECOM 

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Papago Park Military Reservation, Arizona 

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 

SI field activities were conducted from 19 April to 22 April 2021 and consisted of utility clearance, 

surface soil sampling, and low-flow groundwater sampling. Field activities were conducted in 

accordance with the SI QAPP Addendum (AECOM, 2021a), except as noted in Section 5.7. 

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

LC/MS/MS compliant with QSM 5.3 Table B-15 to fulfill the project DQOs:

• 18 surface soil grab samples from 18 boring locations; and

• Four groundwater samples from four permanent monitoring wells.

The information gathered during this investigation was used to determine if PFOA, PFOS, and/or

PFBS were present at or above SLs. Additionally, the CSM was refined to assess whether a 

potentially complete pathway exists between the source and potential receptors for potential 

exposure to PFOA, PFOS, and PFBS at the AOI, which is described in Section 7. 

8.2 SI Goals Evaluation

As described in Section 4.2, the SI activities were designed to achieve six main goals or DQOs. 

This section describes the SI goals and the conclusions that can be made for each based on the 

data collected during this investigation. 

1. Determine the presence or absence of PFOA, PFOS, and PFBS at or above SLs. 

PFOA, PFOS, and PFBS were detected at the facility in soil and groundwater. PFOA, 

PFOS, and PFBS were detected both at the source areas, as well as at the facility 

boundary. PFOA and PFOS in groundwater at the facility boundary exceeded the SL of 40 

ng/L (individually). The detected concentrations of PFOA, PFOS, and PFBS in soil 

samples from AOI 1 were below their respective SLs. 

2. Develop information to potentially eliminate a release from further consideration because 

it is determined that it poses no significant threat to human health or the environment.

Due to the grouping of the potential release areas in AOI 1 and position of the sample 

locations, no one potential release area can be directly linked to the groundwater 

exceedances. Therefore, no release areas can be eliminated from further consideration 

at this time. 

3. Determine the potential need for a TCRA (applies to drinking water only). The primary 

actions that will be considered include provision of alternative water supplies or wellhead 

treatment. 

Records from the AZDEMA indicate that there are no drinking water or irrigation wells 

present at or downgradient of the facility. Therefore, a TCRA is not needed. 

4. Collect data to better characterize the release areas for more effective and rapid initiation 

of a RI (if determined necessary).
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 8-2

The geological data collected as part of the SI indicated a thin layer of unconsolidated soil

exists over competent bedrock. The limited penetration depth of the soil borings did 

confirm that future RI-level sampling would be focused of surface soil sampling due to the 

bedrock surface being close to ground surface. 

Depth to water ranged from 14 to 21 feet bgs in the existing monitoring wells sampled. 

The apparent groundwater flow direction was south-southeast; however, spatial coverage 

of the monitoring wells did not provide a representative understanding of groundwater flow 

across the AOI. A more detailed groundwater investigation may be performed as part of a 

future RI, which would evaluate the hydrogeologic conditions of the shallow aquifer, as 

well as, determine nature and extent of the PFOA and PFOS exceedances.

5. If PFOA, PFOS, and PFBS are determined to be present, aim to evaluate whether the 

concentrations can be attributed to on-facility or off-facility sources that were identified 

within 4 miles of the installation as part of the PA (e.g., fire stations, major manufacturers, 

other DoD facilities).

Based on the evaluation of soil and groundwater data and the documented history and 

use of AFFF at PPMR, the results of the SI indicate that the source of PFOA, PFOS, and 

PFBS at the facility is likely attributable to ARNG activities. 

6. Determine whether a potentially complete pathway exists between the source and 

potential receptors and whether ARNG is the likely source of the contamination. 

Detections of PFOA, PFOS, and PFBS in soil at and adjacent to the source area in 

combination with PFOA and PFOS exceedances in groundwater at the facility boundary 

indicate there is a potentially complete pathway between source and receptor. 

8.3 Outcome 

Based on the CSM updated with SI findings, there is potential for exposure to receptors on facility

resulting from historical DoD activities. Detected concentrations of the three target PFAS were 

compared to the project SLs in soil and groundwater as listed in Table 6-1. The following bullets 

summarize the SI results: 

• PFOA and PFOS were detected in groundwater at AOI 1 and exceeded the individual SL 

of 40 ng/L, with maximum concentrations of 292 ng/L and 170 ng/L at locations MW-25

and MW-26, respectively. PFBS was also detected in groundwater at AOI 1, but it did not 

exceed the SL. Based on the results of the SI, further evaluation of AOI 1 is warranted in 

an RI.

• The detected concentrations of PFOA, PFOS, and PFBS in soil samples from the AOI 

were below the SLs. 

Table 8-1 summarizes the SI outcome for soil and groundwater. Based on the CSM developed 

and revised in light of the SI findings, there is a potential for exposure to receptors caused by DoD 

activities at or adjacent to the facility. 

Table 8-2 summarizes the rationale used to determine if the AOI should be considered for further 

investigation under CERCLA and undergo an RI. Based on the results of this SI, further evaluation 

is warranted in an RI for AOI 1.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 8-3

Table 8-1: Summary of Site Inspection Findings

AOI Potential PFAS 

Release Area

Soil – 

Source Area

Groundwater – 

Source Area

Groundwater –

Facility 

Boundary

1 

Army Aviation and 

Support Facility #1 and 

Vicinity

N/A

Legend:

N/A = Not applicable 

= detected; exceedance of the screening levels

= detected; no exceedance of the screening levels

= not detected

Table 8-2: Site Inspection Recommendations

AOI Description Rationale Future Action

1 

Army Aviation and 

Support Facility #1 

and Vicinity

Exceedances of SLs in groundwater within 

permanent monitoring wells at the facility 

boundary. No exceedances of SLs in soil. 

Proceed to RI 
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 8-4

THIS PAGE INTENTIONALLY BLANK
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 9-1

9. References

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

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

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

W912DR17F0192. 9 March.

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

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

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

AECOM. 2020. Final Preliminary Assessment Report, Papago Park Military Reservation, 

Phoenix, Arizona, Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA) 

Impacted Sites ARNG Installations, Nationwide Contract No. W912DR-12-D0014/W912DR17F0192. September. 

AECOM. 2021a. Final Site Inspection Uniform Federal Policy-Quality Assurance Project Plan 

Addendum, Papago Park Military Reservation, Phoenix, Arizona, Perfluorooctane Sulfonic 

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

Nationwide. March. 

AECOM. 2021b. Final Site Safety and Health Plan, Papago Park Military Reservation, Phoenix, 

Arizona, Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA) Impacted 

Sites ARNG Installations, Nationwide. April.

Assistant Secretary of Defense. 2021. Investigation Per- and Polyfluoroalkyl Substances within 

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

15 September.

ADEQ. 2017. Papago Park Military Reservation – Site History. Papago Park Military Reservation. 

azdeq.gov/papago-park-military-reservation-site-history.

ADEQ. 2018. Papago Park Military Reservation. azdeq.gov/papago-park-military-reservation. 

Arizona State Climate Office. 2019. Climate of Phoenix Summary. Arizona State Climate Office: 

https://azclimate.asu.edu/climate/climate-of-phoenix-summary/.

DA. 2016. Army Guidance to Address Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic 

Acid (PFOA) Contamination. August.

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

4 September.

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

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

DoD. 2019b. General Data Validation Guidelines. Environmental Data Quality Workgroup. 4 

November.

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

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

decontamination fluids). Revision 1. March.

EEC. 2005. Decision Document Administrative Closure of 13 Sites Papago Park Military 

Reservation Phoenix, Arizona. National Guard Bureau Arizona Department of Emergency and 

Military Affairs.
Site Inspection Report

Papago Park Military Reservation, Arizona 

AECOM 9-2

GEC-SA&B. 2005. Environmental Baseline Survey Tempe Armory. Phoenx: GEC-SA&B. 

Guelfo, J.L. and Higgins, C.P. 2013. Subsurface transport potential of perfluoroalkyl acids ad 

aqueous film-forming foam (AFFF)-impacted sites. Environmental Science and Technology 

47(9): 4164-71.

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

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

ITRC. 2018. Environmental Fate ant Transport for Per- and Polyfluoroalkyl Substances. March. 

NOAA. 2019. Climate Data Online Database. https://www.ncdc.noaa.gov/cdoweb/datatools/normals (Accessed June 2019).

TechLaw, Inc. 2004. Final Historical Records Review Papago Park Military Reservation Phoenix, 

Arizona. U.S. Army Corps of Engineers, Sacramento District. General Services Administration 

(GSA) Schedule Number: GS-10F-0168J. Delivery Order No. DACA05-03-F-0024

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

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

(CERCLA). 

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

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

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

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

Assessments). December.

USEPA. 2005. Federal Facilities Remedial Site Inspection Summary Guide. 

USEPA. 2006. Guidance on Systematic Planning using the Data Quality Objectives Process. 

February.

USEPA. 2016a. Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA). Office of 

Water (4304T). Health and Ecological Criteria Division, Washington, DC 20460. US USEPA 

Document Number: 822-R-16-005. May 2016.

USEPA. 2016b. Drinking Water Health Advisory for Perfluorooctane Sulfonate (PFOS). Office of 

Water (4304T). Health and Ecological Criteria Division, Washington, DC 20460. US USEPA 

Document Number: 822-R-16-004. May 2016.

USEPA. 2017a. UCMR 3 (2013-2015) Occurrence Data by State. Occurrence Data for the 

Unregulated Contaminant Monitoring Rule. Accessed 9 July 2019 at 

https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule. 

January.

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

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

Innovation. January.

USFWS IPCA. 2021. Information for Planning and Consultation, Endangered Species, Location: 

PPMR, Maricopa, Arizona. Environmental Conservation Online System. Accessed 18 August

2021 athttps://ecos.fws.gov/ipac/location/B3CKDQXEMZFQ5LY65CCHZ2COBI/resources. 

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

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

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