FINAL

Preliminary Assessment Report

Grand Prairie Army Aviation 

Support Facility 

Texas

Perfluorooctanesulfonic Acid (PFOS) and Perfluorooctanoic 

Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

July 2020

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

i

Table of Contents

Executive Summary .................................................................................................................... 1

1. Introduction ........................................................................................................................ 5

1.1 Authority and Purpose .............................................................................................. 5

1.2 Preliminary Assessment Methods ............................................................................. 5

1.3 Report Organization .................................................................................................. 6

1.4 Facility Location and Description............................................................................... 6

1.5 Facility Environmental Setting ................................................................................... 7

1.5.1 Geology ......................................................................................................... 7

1.5.2 Hydrogeology ................................................................................................. 7

1.5.3 Hydrology ....................................................................................................... 8

1.5.4 Climate ........................................................................................................... 8

1.5.5 Current and Future Land Use ......................................................................... 8

2. Fire Training Areas ........................................................................................................... 12

3. Non-Fire Training Areas ................................................................................................... 13

3.1 Wash Rack Area ..................................................................................................... 13

3.2 Ramp to Flight Line ................................................................................................. 13

3.3 Hangar .................................................................................................................... 14

3.4 Armory .................................................................................................................... 14

3.5 Hazardous Materials Storage Building .................................................................... 14

3.6 Fuel Station ............................................................................................................ 14

3.7 Firetruck .................................................................................................................. 14

3.8 Landfills .................................................................................................................. 14

4. Emergency Response Areas ............................................................................................ 17

5. Adjacent Sources ............................................................................................................. 18

5.1 Peace Prairie Hangar .............................................................................................. 18

5.2 Bio-Ecology Systems Inc. ....................................................................................... 18

5.3 Industrial Activities .................................................................................................. 18

6. Preliminary Conceptual Site Model .................................................................................. 21

6.1 AOI 1 Wash Rack, Hazardous Materials Storage Building, and Fuel Station ........... 21

6.2 AOI 2 Flight Line Ramp ........................................................................................... 22

6.3 AOI 3 Historic Location of Firetruck ......................................................................... 22

7. Conclusions ..................................................................................................................... 25

7.1 Findings .................................................................................................................. 25

7.2 Uncertainties ........................................................................................................... 25

7.3 Potential Future Actions .......................................................................................... 26

8. References ...................................................................................................................... 29
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

ii

Figures

Figure ES-1 Summary of Findings

Figure ES-2 Preliminary Conceptual Site Model, AOI 1, 2, and 3

Figure 1-1 Facility Location

Figure 1-2 Groundwater Features

Figure 1-3 Surface Water Features

Figure 3-1 Non-Fire Training Areas

Figure 5-1 Adjacent Sources

Figure 6-1 Areas of Interest

Figure 6-2 Preliminary Conceptual Site Model, AOI 1, 2, and 3

Figure 7-1 Summary of Findings

Tables

Table ES-1: AOIs at Grand Prairie AASF

Table 7-1: AOIs at Grand Prairie AASF

Table 7-2: Uncertainties

Table 7-3: Rationale

Appendices

Appendix A Data Resources

Appendix B Preliminary Assessment Documentation

B.1 Interview Records

B.2 Visual Site Inspection Checklists

B.3 Conceptual Site Model Information

Appendix C Photographic Log
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

iii

Acronyms and Abbreviations

%

AECOM

percent

AECOM Technical Services, Inc.

AASF Army Aviation Support Facility

AFFF aqueous film forming foam

AOI area of interest

ARNG Army National Guard

CERCLA Comprehensive Environmental Response, Compensation, and Liability

Act

CSM conceptual site model

DNAS Dallas Naval Air Station

EDRTM Environmental Data Resources, Inc.TM

oF degrees Fahrenheit

FTA fire training area

GMI Geo-Marine, Inc.

HA Health Advisory

IED Installations and Environment Division

NOAA National Oceanic and Atmospheric Administration

OMS operational maintenance shop

OWS oil-water separator

PA Preliminary Assessment

PFAS per- and poly-fluoroalkyl substances

PFOA perfluorooctanoic acid

PFOS

RCRA

perfluorooctanesulfonic acid

Resource Conservation and Recovery Act

ppt parts per trillion

SI

TtNUS

Site Inspection

Tetra Tech NUS, Inc.

TXARNG Texas Army National Guard

UCMR3 Unregulated Contaminant Monitoring Rule 3

US United States

USACE United States Army Corps of Engineers

USEPA United States Environmental Protection Agency

USPFO United States Property & Fiscal Office

VOC volatile organic compound

VSI visual site inspection

WWTP wastewater treatment plant
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

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Executive Summary

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

Inspections (SIs) for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA)

Impacted Sites at ARNG Facilities Nationwide. A PA for per- and polyfluoroalkyl substances

(PFAS)-containing materials was completed for Grand Prairie Army Aviation Support Facility

(AASF) (also referred to as the “facility”) in Grand Prairie, Texas, to assess potential PFAS release

areas and exposure pathways to receptors. The performance of this PA included the following

tasks:

· Reviewed available administrative record documents and Environmental Data Resources,

Inc. (EDR)TM report packages to obtain information relevant to potential PFAS releases, such

as: drinking water well locations, historical aerial photographs, Sanborn maps, and

environmental compliance actions in the area surrounding the facility;

· Conducted a 1-day site visit on 23 April 2019 and completed visual site inspections (VSI) at

locations where PFAS-containing materials were suspected of being stored, used, or

disposed;

· Interviewed personnel during the site visit who were associated with Grand Prairie AASF

activities including the Grand Prairie AASF Environmental Officer (on site since 2009), the

Mechanic Supervisor (on site since 1991) and two Standardization Instructors (on site since

1989 and 1998);

· Identified areas of interest (AOIs) and developed a preliminary conceptual site model (CSM)

to outline the potential release, pathway, and receptors of PFAS for Grand Prairie AASF.

Five suspected PFAS releases/storage areas were identified during the PA, as described below.

These releases constitute three AOIs identified at Grand Prairie AASF. The AOIs are shown in

Figure ES-1 and summarized in Table ES-1 below.

Table ES-1: AOIs at Grand Prairie AASF

Area of

Interest

Description Used by Release Dates

AOI 1 Releases during AFFF fire extinguisher

testing/training with mobile carts at the wash

rack; discharged to oil-water separator

(OWS). Depending on the position of a

diverter valve, the flow path after the OWS is

either to the sanitary sewer system or to the

street, then to Cottonwood Bay via surface

water flow. AFFF stored in the hazardous

materials storage building and in Tri-MaxTM

units at the Fuel Station have been added to

AOI 1 because of the potential for AFFF

spills in those areas.

TXARNG 2000-2012

AOI 2 Releases during AFFF fire extinguisher

testing/training with mobile carts at the

ramp/taxiway. Surface runoff could have

potentially migrated to surrounding grassy

areas.

TXARNG 2000-2012
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

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AOI 3 AFFF was stored in the firetruck historically

located in the southern part of the facility.

Although there are no recorded uses of

AFFF in the area, there is the possibility of

leaking in the area.

TXARNG Unknown

Based on the reported AFFF release/storage at these AOIs, there is potential for exposure to

PFAS contamination in surface soil to site and construction workers and in subsurface soil to

construction workers via inhalation and accidental ingestion. The preliminary CSM for AOIs 1, 2,

and 3 is shown on Figure ES-2. Based on the US Environmental Protection Agency (USEPA)

Unregulated Contaminant Monitoring Rule 3 (UCMR3) data, it was indicated that no PFAS were

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

the facility. PFAS analyses performed in 2016 had method detection limits 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.
Historic Location 

of Firetruck

Ramp

Fuel Station Hazardous Materials

Storage Building

Wash Rack

Peace Prairie Hangar

with AFFF Fire

Suppression System

Peace Prairie

Hangar OWS

Peace Prairie

Wash Rack

Armory

Organizational

Maintenance Shop

Hangar

Vought/LTV

Aerospace

Mountain

Creek Lake

Cottonwood

Bay

Cottonwood Creek

Diversion Channel

AOI 2

AOI 1

AOI 3

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:9,600

4/28/2020 ­ Figure ES-1 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Summary of Findings

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\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_ES-1_Grand_Prairie_AASF_Summary.mxd

0 400 800 1,600

Feet

Legend

Area of Interest

Potential PFAS Release

No Suspected Release

Approximate Facility

Boundary per TX ARNG

Water Body

River/Stream

3
Media

SOURCE PATHWAY RECEPTOR

AOI 1

AOI 2

AOI 3

AFFF release

during AFFF fire

extinguisher testing/

training at the wash

rack and flight line

ramp, and storage

of AFFF in the Haz.

Materials Storage

Building, the Fuel

Station, and the

Firetruck

PFAS in

Surface Soil

near AOIs

PFAS in

Subsurface

Soil via soil

infiltration

and from

leaks in

drains,

OWS, and

underground

piping

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

particulate

Surface Soil

at AOI

Surface

Water/

sediment

Subsurface

Soil

Shallow

Groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors:

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

Site

Worker

Construction

Worker Resident Trespasser/Recreational User

Site

Worker

Construction

Worker Resident Trespasser/

Recreational User

/ / /

/ /

LEGEND

/ /

/ / /

Figure ES-2

Preliminary Conceptual Site Model, AOI 1, 2, and 3

Potential

Off-Facility

Source Not

under

Control of

ARNG

/

/

/

/

/

/ /

/

/

Note:

1. The residential receptor

refers to an off-facility

receptor.

/

4
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

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1. Introduction

1.1 Authority and Purpose

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 at ARNG Facilities 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 is assessing potential effects on human health related to processes at their facilities

that used per- and poly-fluoroalkyl substances (PFAS), primarily releases of aqueous film forming

foam (AFFF) although other sources of PFAS are possible. In addition, the ARNG is assessing

businesses or operations adjacent to the ARNG facility (not under the control of ARNG) that could

potentially be responsible for a PFAS release.

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 at both federal and state levels continues to evolve. The US Environmental Protection

Agency (USEPA) issued Drinking Water Health Advisories (HAs) for PFOA and PFOS in May

2016, but there are currently no promulgated national standards regulating PFAS in drinking

water.

This report presents findings of a PA for PFAS-containing materials at Grand Prairie Army Aviation

Support Facility (AASF) in Grand Prairie, Texas, in accordance with the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA), as amended, the National

Oil and Hazardous Substances Pollution Contingency Plan (40 Code of Federal Regulations Part

300), and Army requirements and guidance.

This PA documents the locations where PFAS were historically stored and reportedly released

into the environment at Grand Prairie AASF. The term PFAS will be used throughout this report to

encompass all PFAS chemicals being evaluated, including PFOS and PFOA, which are key

components of AFFF.

1.2 Preliminary Assessment Methods

The performance of this PA included the following tasks:

· Reviewed available administrative record documents and Environmental Data Resources,

Inc. (EDR)TM report packages to obtain information relevant to potential PFAS releases, such

as: drinking water well locations, historical aerial photographs, Sanborn maps, and

environmental compliance actions in the area surrounding the facility;

· Conducted a 1-day site visit on 23 April 2019 and completed visual site inspections (VSIs) at

locations where PFAS-containing materials were suspected of being stored, used, or

disposed;

· Interviewed personnel associated with Grand Prairie AASF activities during the site visit

including the Grand Prairie AASF Environmental Officer (on site since 2009), the Mechanic

Supervisor (on site since 1991) and two Standardization Instructors (on site since 1989 and

1998);
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

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· Identified areas of interest (AOIs) and developed a preliminary conceptual site model (CSM)

to outline the potential release, pathway, and receptors of PFAS for Grand Prairie AASF.

1.3 Report Organization

This report has been prepared in accordance with the USEPA Guidance for Performing

Preliminary Assessments under CERCLA (USEPA, 1991). The report sections and descriptions

of each are:

· Section 1 – Introduction: identifies the project purpose and authority and describes the

facility location, environmental setting, and methods used to complete the PA

· Section 2 – Fire Training Areas: describes the potential or suspected fire training areas

(FTAs) at the facility identified during the site visit

· Section 3 – Non-Fire Training Areas: describes other locations of potential or suspected

PFAS releases at the facility identified during the site visit

· Section 4 – Emergency Response Areas: describes areas of suspected or potential AFFF

release at the facility, specifically in response to emergency situations

· Section 5 – Adjacent Sources: describes sources of PFAS release adjacent to the facility

that are not under the control of ARNG

· Section 6 – Preliminary Conceptual Site Model: describes the pathways of PFAS transport

and receptors at the AOIs

· Section 7 – Conclusions: summarizes the data findings and presents the conclusions of the

PA

· Section 8 – References: provides the references used to develop this document

· Appendix A – Data Resources

· Appendix B – Preliminary Assessment Documentation

· Appendix C – Photographic Log

1.4 Facility Location and Description

Grand Prairie AASF (also referred to as the “facility”), home to the 149th Aviation Regiment of the

Texas ARNG (TXARNG), is located within the southwest portion of the former Dallas Naval Air

Station (DNAS), which was decommissioned in 1998. The facility is located 12 miles southwest

of downtown Dallas and is situated adjacent to the northwest shore of Mountain Creek Lake

(Figure 1-1), on property that overlaps into the cities of Dallas and Grand Prairie, Texas. As noted

in the lease agreement (Appendix A), the TXARNG began leasing approximately 40 acres of

land situated in Dallas County, Texas in 1975. Historically, the DNAS has provided support to the

following tenants:

· Texas Air National Guard

· US Army Reserve

· TXARNG

· Various Navy and Marine groups

With the exception of TXARNG operations, the majority of military operations ceased at DNAS in

September 1998, and the air station was put into caretaker status (Tetra Tech NUS, Inc. [TtNUS],
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

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2001). The current TXARNG facility houses a hangar, a wash rack, fuel station, ramp and flight

line, a hazardous materials storage building, an organizational maintenance shop (OMS), and an

armory. The Grand Prairie AASF Hangar does not have an AFFF fire suppression system. Current

activities at the Grand Prairie AASF include helicopter maintenance and training.

Historical operations at Grand Prairie AASF have included training at the Peace Prairie Hangar,

located northeast of the current TXARNG facility boundary. The Peace Prairie Hangar has an

AFFF fire suppression system and is adjacent to the Peace Prairie wash rack and oil-water

separator (OWS).

1.5 Facility Environmental Setting

Grand Prairie AASF is located in north-central Texas, approximately 325 miles north of the Gulf

of Mexico. The facility is situated near the headwaters of the Trinity River that flow in the upper

margins of the Coastal Plain.

1.5.1 Geology

The general stratigraphic sequence present throughout the TXARNG facility consists of Holocene

and Pleistocene alluvial terrace deposits overlaying the Cretaceous Eagle Ford Shale (Figure 1-

2). The upper soil horizons and alluvium have been disturbed locally by industrial development; 

therefore, shallow surface and subsurface soils are composed of fill materials in some areas. The

lithology of sediments is primarily clay and silty clay. The clays are interspersed with sporadic

deposits of streambed sand and gravel (Geo-Marine, Inc [GMI], July 2002).

1.5.2 Hydrogeology

The surficial aquifer below the facility is within the alluvium overburden and the weathered portion

of the underlying shale. This aquifer is heterogeneous and exhibits characteristics of unconfined

aquifer systems and semi-confined to confined aquifer systems. These two types of aquifer

systems are interconnected hydraulically to the adjacent water bodies; Mountain Creek Lake,

Cottonwood Bay, and the Diversion Channel. Groundwater contour elevations are very similar to

the land surface topography. In the central section of the facility, the potentiometric surface is

primarily flat. Along the Cottonwood Bay and the Diversion Channel shorelines, the potentiometric

surface is extremely steep, and along the east portion of the facility, across the flight line toward

Mountain Creek Lake, the potentiometric surface is moderately steep. The groundwater flow

pattern is radial and flows eastward toward Mountain Creek Lake, northward in the direction of

Cottonwood Bay, and westward toward the Diversion Channel. Seepage velocity of the

groundwater underlying the facility within the overburden is estimated to range from 0.12 to 0.23

foot per day (TtNUS, 2001) (Figure 1-2).

Shallow groundwater in the alluvial section flows primarily through the semi-confined to confined

zones and in unconfined zones of sands and clayey sands. Shallow groundwater is estimated to

be approximately 20 to 25 feet below ground surface at the facility (GMI, December 2003). Clay,

silty clay, sandy clay, and gravelly clay comprise the semi-confined zones that are cut by joints,

microfractures, partings, and other zones of macroporosity. The confined zones may be

interconnected with the weathered and jointed upper surface of the Eagle Ford Shale. The surficial

aquifer underlying the facility is most likely recharged by the downward migration of rainwater

through the unconfined aquifer areas of the vadose zone. The aquifer is most likely recharged in

semi-confined outcropping areas upgradient. The surficial aquifer is recharged at a lesser extent

by downward migration through the vadose zone. Direction of groundwater flow was determined

from potentiometric surface maps developed from static water level data collected during five

separate water level gauging events (TtNUS, 2001).
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

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The facility’s drinking water is supplied by the City of Grand Prairie. A query of the Texas Water

Development Board Submitted Drillers Reports Database identified 1 public supply well, 8

industrial water supply wells, and 97 monitoring wells within a one-mile radius of the facility. The

public supply well is owned by the City of Grand Prairie and was installed 2,084 feet below ground

surface. The industrial water supply wells range in depth from 1,180 to 2,148 feet and are located

on the north side of Cottonwood Bay, in property owned historically by L.T.V. Aerospace

Corporation. The majority of the monitoring wells are located in the same area north of the facility,

but a few are located approximately 0.5 mile south of the facility. The monitoring wells range in

depth from 10 to 68 feet. One irrigation well is located just over 1 mile west of the facility. According

to the Submitted Drillers Reports Database, the irrigation well is owned by the First Church of the

Nazarene (Figure 1-2). Based on the USEPA UCMR3 data, it was indicated that no PFAS were

detected in a public water system above the USEPA HA level within 20 miles of the facility. PFAS

analyses performed in 2016 had method detection limits 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

1.5.3 Hydrology

Surface water in the vicinity of Grand Prairie AASF flows primarily across paved or grassy areas

and into the storm drainage system that discharges into Cottonwood Bay, the Diversion Channel,

and Mountain Creek Lake (Figure 1-3). The stormwater drainage system follows the predominant

slope of the ground surface and drains into the lake. Mountain Creek Lake drains to the northeast

from the spillway located approximately 1.5 miles east of the facility (TtNUS 2001). .

1.5.4 Climate

The Dallas-Fort Worth climate is humid subtropical with hot summers. The climate is also

continental, characterized by a wide annual temperature range. Precipitation also varies

considerably, ranging from less than 20 to more than 50 inches. Average annual precipitation for

the facility is 37.35 inches. Winters are mild, but northers occur about three times each month

and often are accompanied by sudden drops in temperature. The highest temperatures of

summer are associated with fair skies, westerly winds and low humidity. Characteristically, hot

spells in summer are broken into three-to-five day periods by thunderstorm activity. There are only

a few nights each summer when the low temperature exceeds 80 degrees Fahrenheit (oF).

Summer daytime temperatures frequently exceed 100°F. Average yearly minimum and maximum

temperatures are 36.5°F and 96.2°F, respectively, with an average annual temperature of 66.6°F.

Throughout the year, rainfall occurs more frequently during the night. Usually, periods of rainy

weather last for only a day or two and are followed by several days with fair skies. A large part of

the annual precipitation results from thunderstorm activity, with occasional heavy rainfall over brief

periods of time. Thunderstorms occur throughout the year, but are most frequent in the spring

(National Oceanic and Atmospheric Administration [NOAA], 2019).

1.5.5 Current and Future Land Use

The Grand Prairie AASF currently includes storage buildings, operational maintenance shop

(OMS) activities, training, administration, and a hangar. Current land use in the direct vicinity of

the Grand Prairie AASF includes residential to the west, industrial to the north, open areas and

parks, commercial and retail, and governmental institutions. A representative from the Texas

Military Department noted plans to move the Grand Prairie AASF to the Naval Air Station Joint

Reserve Base Fort Worth soon. No other future changes to the current use were noted during

personnel interviews.
CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:63,360

4/28/2020 ­ Figure 1-1 PM RG 4/28/2020

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\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_1-1_Grand_Prairie_AASF_Facility_Location.mxd

Legend

Approximate Facility

Boundary per TX ARNG

DNAS Boundary

0 0.5 1 2

Miles

^_

Grand Prairie AASF

9
!5

!5

!5

!5

!5 !5

!5

!5

!C(

A!

A!

A! A!

A! A!

A! A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A! A!

!5

Mountain

Creek Lake

West Fork Trinity River

Cottonwood Cree k

Cottonwood Bay

Diversion Channel

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:31,680

4/28/2020 ­ Figure 1-2 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Groundwater Features

Base Map: Source: Esri, DigitalGlobe, GeoEye,

Earthstar Geographics, CNES/Airbus DS, USDA, USGS,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_1-2_Grand_Prairie_AASF_Groundwater.mxd

Legend

Approximate Facility

Boundary per TX ARNG

Water Body

Wetland

River/Stream

Canal/Ditch

Pipeline

Inferred Groundwater Flow

Direction

Geology

Alluvium

Fluvial Terrace Deposits

Eagle Ford Group

Wells

A! Monitor Well

!5 Irrigation Well

!5 Industrial Well

!C( Public Supply Well

0 0.25 0.5 1

Miles

10
Delaware Creek-West

Fork Trinity

River Watershed

Cottonwood

Creek-Mountain Creek

Lake Watershed

Mountain

Creek Lake

West Fork Trinity River

CottonwoodCreek

Cottonwood Bay

Diversion Channel

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:31,680

4/28/2020 ­ Figure 1-3 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Surface Water Features

Base Map: Source: Esri, DigitalGlobe, GeoEye,

Earthstar Geographics, CNES/Airbus DS, USDA, USGS,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_1-3_Grand_Prairie_AASF_Surface_Water.mxd

0 0.25 0.5 1

Miles

Legend

Approximate Facility

Boundary per TX ARNG

Water Body

River/Stream

Surface Water Flow

Direction

11
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

12

2. Fire Training Areas

With the exception of mobile cart extinguisher testing/training at the wash rack area and ramp to

the flight line (described in Sections 3.1 and 3.2, respectively), Grand Prairie AASF personnel

confirmed there are no designated FTAs at the facility.
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

13

3. Non-Fire Training Areas

In addition to FTAs, the PA evaluated areas where PFAS-containing materials may have been

broadly used, stored, or disposed. This may include buildings with fire suppression systems, paint

booths, AFFF storage areas, and areas of compliance demonstrations. Information on these

features obtained during the PA are included in Appendices A and B. The Grand Prairie AASF

comprises the ramp to the flight line, several buildings (hangar, armory, administrative buildings,

and storage), and a wash rack area. These non-FTAs were investigated during the PA. These

and other areas are described below and shown on Figure 3-1, with photographs provided in

Appendix C.

Wastewater that collects in the wash rack flows to an OWS and then (depending of the positioning

of a manual diverter valve) discharges to either the sanitary sewer system or to the street, where

it then flows to Cottonwood Bay. The sanitary sewer system extends generally southwestward,

adjacent to the main entrance road across the Diversion Channel and eventually flows to the

Trinity River Authority of Texas Central Regional Wastewater Treatment Plant (WWTP) located at

6500 W. Singleton Blvd., Dallas, Texas 75212.

3.1 Wash Rack Area

The wash rack area is located to the northeast of the hangar and hazardous materials storage

building. From 2000 to 2012, mobile firefighting carts containing AFFF solution (Tri-MaxTM units)

were serviced at the wash rack, approximately once every two years. The AFFF solution stored

in the Tri-MaxTM units was poured down the drain in the wash rack. There were approximately six

Tri-MaxTM units at the facility that were serviced in this way. Additionally, training took place with

the Tri-MaxTM units at the wash rack approximately every two years from 2000 to 2012. Training

on the wash rack area typically occurred with two or three Tri-MaxTM units. While the majority of

fluids drained to an OWS, it is possible that AFFF produced during fire training activities reached

areas surrounding the wash rack and subsequently infiltrated into the soil. Depending on the

positioning of a manual diverter valve, fluids entering the wash rack flowed either to the sanitary

sewer system or were discharged to the street northeast of the OWS. The troops had to manually

change the system from discharge to the sanitary sewer to discharge to surface water depending

on the work they were performing. Interviews indicated that the valve may not have been diverted

to the sanitary sewer for some events where the TriMaxTM units were emptied or used.

The OWS was constructed in 1984-1985, and the Resource Conservation and Recovery Act

(RCRA) Facility Investigation conducted in 2001 revealed leaking joints in the sewer system, so

PFAS contamination may have infiltrated to subsurface soil via leaks in drains, OWS or

underground wastewater conveyance piping beneath the wash rack, or leaks along piping from

the facility to the municipal WWTP. To the best of their knowledge, TXARNG staff who had been

working at the facility since 1989 reported no other releases in this area. Geographic coordinates

for the wash rack are 32°43'57.0"N; 96°58'40.7"W.

3.2 Ramp to Flight Line

The ramp to the flight line is a large concrete pad located directly to the southeast of the hangar

in the central portion of the facility. Currently, non-AFFF mobile firefighting carts are available on

the flight line in the case of an emergency. According to PA interviews, AFFF was used during fire

training activities on the ramp to the flight line between 2000 and 2012. During training events,

Tri-MaxTM wheeled portable units were used on the ramp to put out fires. Two or three Tri-MaxTM

units were trained with during each training event, which occurred approximately every two years.

During training events, a burn barrel was set on fire, and TXARNG personnel practiced using the

Tri-MaxTM units to extinguish the fire. Wastewater and precipitation that falls on the ramp to the
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

14

flight line most likely drains to perimeter grassy areas, then infiltrates into the subsurface. The

geographic coordinates for the ramp to the flight line are 32°43'53.5"N; 96°58'42.4"W.

3.3 Hangar

The hangar is located in the central portion of the facility, adjacent to the northwestern side of the

flight line. The hangar is used for helicopter maintenance, storage, and training. The current

hangar was built in 1976. TXARNG staff report the hangar is not equipped with a fire suppression

system. The geographic coordinates for the hangar are 32°43'54.4"N; 96°58'43.1"W.

3.4 Armory

The armory is located to the southwest of the hangar, just north of the Diversion Channel. The

armory is used for mainly administrative purposes and contains various offices, classrooms, an

assembly hall, a kitchen, and storage cages for personnel equipment (GMI, July 2002). No

TXARNG staff reported the historic or current use of AFFF in the armory building. The geographic

coordinates for the AASF hangar are 32°43'50.2"N; 96°58'46.3"W.

3.5 Hazardous Materials Storage Building

The hazardous materials storage building is located northeast of the hangar. Various hazardous

materials are stored inside the building. Historically, 30 5-gallon sealed buckets of 3 percent (%)

AFFF were stored inside the building. The 5-gallon buckets were added to helicopter buckets for

firefighting offsite. Around 2012, the 5-gallon buckets of AFFF were removed from the facility and

sent to the Camp Mabry United States Property & Fiscal Office (USPFO) in Austin, Texas. To the

best of their knowledge, TXARNG staff who had been working at the facility since 1989 reported

no releases of any materials in this area. No floor drain was observed in the hazardous materials

storage building. Geographic coordinates for the hazardous materials storage building are

32°43'56.3"N; 96°58'42.7"W.

3.6 Fuel Station

Historically, AFFF containing Tri-MaxTM units were stationed near the Fuel Station at the facility.

TXARNG staff who had been working at the facility since 1989 reported no releases of any

materials in this area. Precipitation and wastewater flow in this area would most likely infiltrate

into the soil. Geographic coordinates for the fuel station are 32°43'56.0"N; 96°58'39.5"W.

3.7 Firetruck

A large green Osh KoshTM firetruck was historically located in the southern corner of the facility.

The firetruck was equipped with AFFF, but the foam was never deployed. Eventually, the firetruck

was turned in, and it no longer is located at the facility. A small containment was located beneath

the firetruck in case of spills. TXARNG staff who had been working at the facility since 1989

reported no releases of any materials in this area. Precipitation and wastewater flow in this area

would most likely infiltrate into the surrounding grassland. Geographic coordinates for the fuel

station are: 32°43'45.7"N; 96°58'40.5"W.

3.8 Landfills

During PA interviews, TXARNG staff noted no current or former landfills located at or in the vicinity

of Grand Prairie AASF.
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

15

Landfills are not usually a primary release area of PFAS, but materials disposed in landfills may

create a secondary source of contamination. Such materials may include sludge from a WWTP

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

waterproofing uniforms or boots.
Cottonwood

Bay

Diversion Channel

Armory

Organizational

Maintenance Shop

Hangar

Historic Location

of Firetruck

Ramp

Fuel Station

Hazardous Materials

Storage Building

Wash Rack

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:4,200

4/28/2020 ­ Figure 3-1 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Non-Fire Training Areas

Base Map: Source: Esri, DigitalGlobe, GeoEye,

Earthstar Geographics, CNES/Airbus DS, USDA, USGS,

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_3-1_Grand_Prairie_AASF_Non-Fire_Training_Areas.mxd

0 175 350 700

Feet

Legend

Potential PFAS Release

No Suspected Release

Approximate Facility

Boundary per TX ARNG

Water Body

16
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

17

4. Emergency Response Areas

To the best of their knowledge, TXARNG personnel who have been working at the facility since

1989 reported no past emergency responses.
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

18

5. Adjacent Sources

Adjacent sources of potential PFAS include the Peace Prairie Hangar, an adjacent Superfund

site, and industrial activities. Figure 5-1 shows the various adjacent sources described in this

section.

5.1 Peace Prairie Hangar

The Peace Prairie Hangar was built in 1976 and was initially owned and operated by the

TXARNG. Singapore Air Force troops were trained at the Peace Prairie facility by TXARNG

personnel. In 1998, the Peace Prairie Hangar was expanded, and a fire suppression system was

added. The Peace Prairie Hangar is located northeast of the Grand Prairie AASF. An Operations

Officer working at the Peace Prairie Hangar indicated that since he had been at the facility (2013),

the suppression system had never been triggered, and no leaks had been detected. The system

is currently inspected once a month and has been inspected monthly since 2015. The Peace

Prairie Hangar is no longer part of the TXARNG lease and is currently owned by the City of Dallas.

The Peace Prairie Division had Tri-MaxTM units, which hangar maintenance personnel inspected.

Peace Prairie personnel reported training monthly with Tri-MaxTM units. It is unknown where this

training occurred, but it most likely occurred at the Peace Prairie wash rack. AFFF is stored as a

concentrate in the Peace Prairie Hangar and in the Peace Prairie bulk storage facility. Tri-MaxTM

units were serviced by a contractor, and it is not clear what happened to the old solution.

In 2003, the AFFF fire suppression system at the Peace Prairie Hangar released. According to

the TXARNG Environmental Spill Report, less than 150 gallons of ChemguardTM Standard Grade

3% AFFF was released in the Peace Prairie Hangar on 5 May 2003. The accidental release was

caused by a malfunction of the pull station due to vibration, triggering the fire suppression system.

Once the system was triggered, the 3% AFFF chemical mixed with water to produce

approximately 5,000 gallons of liquid and 15,000 gallons of foam that filled the hangar. Facility

personnel washed the liquid/foam mixture into the floor drain, which is connected to holding

sumps and an OWS. Eagle Construction and Environmental was contracted to put the foam/water

and any other liquid in the sumps and the OWS into holding pods in case of rain, awaiting lab

results and then disposal. Some AFFF was released to the ground because of a defective diverter

valve. Approximately 20,000 gallons of liquid and residue were removed and held on site, awaiting

the test results for waste determination and disposal. A waste determination profile was made

after reviewing the test results and the waste profile and test results were sent to Cold Springs

Processing plant. Eagle Construction transported the wastewater to Cold Springs Processing for

disposal. The spill report can be found in Appendix A.

5.2 Bio-Ecology Systems Inc.

The closest Superfund site to the facility (approximately 2.7 miles to the northeast) is the BioEcology Systems Inc. Site, located at 4100 East Jefferson, Grand Prairie, Texas (USEPA Registry

ID 110009313322). Solid waste management activities at the site include contaminated soil and

groundwater with heavy metals and volatile organic compounds (VOCs). Following cleanup,

USEPA took the site off the Superfund program’s National Priorities List in 1996 (USEPA, 2018).

5.3 Industrial Activities

Vought/LTV Aerospace is a military aerospace contractor that historically built engines. The

company is no longer active in the industrial facilities located approximately 1,700 feet north of
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

19

the facility. The land historically owned by Vought Industries now appears to be owned by

Lockheed Martin.
Cottonwood

Bay

Diversion Channel

Vought/LTV

Aerospace

Peace Prairie Hangar

with AFFF Fire

Suppression System

Peace Prairie

Hangar OWS

Peace Prairie

Wash Rack

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:9,600

4/28/2020 ­ Figure 5-1 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Adjacent Source

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\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_5-1_Grand_Prairie_AASF_Adjacent_Source.mxd

0 400 800 1,600

Feet

Mountain

Creek

Superfund Site:

Bio-Ecology

Systems, Inc.

1

2

1

2

0 400 800 1,600

Feet

Legend

Potential PFAS Release

No Suspected Release

Approximate Facility

Boundary per TX ARNG

Water Body

River/Stream

0 3,335 6,670 13,340

Feet

20
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

21

6. Preliminary Conceptual Site Model

Based on the PA findings, the AFFF release area and storage areas associated with the Grand

Prairie AASF wash rack, hazardous materials storage building, and fuel station were identified as

AOI 1. The flight line ramp was identified AOI 2, and the historic location of the firetruck is identified

as AOI 3. This section describes the preliminary CSM components developed for these three

AOIs. The CSM identifies the three components necessary for a potentially complete exposure

pathway: (1) source, (2) pathway, and (3) receptor. If any of these elements are missing, the

pathway is considered incomplete. The AOIs are shown on Figure 6-1, and the preliminary CSM

for AOI 1, 2, and 3 is presented on Figure 6-2.

In general, the potential PFAS exposure pathways 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 is sparse and 

continues to be the subject of PFAS toxicological study. Receptors at Grand Prairie AASF include

site workers, construction workers, trespassers, and residents and recreational users outside the

facility boundary. As described below, the preliminary CSM for the AOIs indicate the specific

receptors that could potentially be exposed to PFAS.

6.1 AOI 1 Wash Rack, Hazardous Materials Storage Building, and

Fuel Station

AFFF was used during fire training from 2000 to 2012 at the wash rack. An unknown quantity of

AFFF was released during these fire training events.

Releases at the wash rack would have been conveyed to the drain and OWS, and then depending

on the positioning of a diverter valve, either flowed to the sanitary sewer system, and ultimately

discharged to the municipal WWTP, or flowed to the street, and ultimately discharged to

Cottonwood Bay. The position of the diverter valve during AFFF use at the wash rack is unknown.

Based on the nature of the release (during maintenance/routine testing/training) it appears

unlikely AFFF would have been discharged to the ground surface outside of the wash rack, except

potentially via runoff to the grassy areas surrounding the wash rack (Figure 6-1). PFAS

contamination may have infiltrated to subsurface soil via leaks in drains, OWS or underground

wastewater conveyance piping beneath the wash rack, or leaks along piping from the facility to

the municipal WWTP. Under such scenarios ground disturbing activities in these areas could

result in site or construction worker exposure to PFAS via inhalation of dust or ingestion of

exposed surface soil, or construction worker exposure to PFAS via inhalation of dust or ingestion

of exposed subsurface soil.

The hazardous materials storage building historically housed 30 5-gallon sealed buckets of 3%

AFFF until 2012. Although there were no known releases of AFFF at the storage building, it is

possible that spills occurred in the area. AFFF spills in the storage building would have most likely

been washed to the nearby wash rack for disposal.

Tri-MaxTM units containing AFFF were stationed at the fuel station in case a fire broke out in the

area. Although there were no reports of Tri-MaxTM use at the fuel station, it is possible that a spill

occurred in the area without being reported. AFFF spills in the fuel station area would most likely

infiltrate into the surrounding soil.

Based on the nature of the possible release, PFAS contamination may have further infiltrated to

subsurface soil at the wash rack or beneath the fuel station. Under such scenarios ground

disturbing activities in these areas could result in site or construction worker exposure to PFAS
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

22

via inhalation of dust or ingestion of exposed surface soil, or construction worker exposure to

PFAS via inhalation of dust or ingestion of exposed subsurface soil.

Potential PFAS contamination may have further infiltrated to shallow groundwater, which is

anticipated to follow topography and flow radially toward Mountain Creek Lake, Cottonwood Bay,

and the Diversion Channel.

6.2 AOI 2 Flight Line Ramp

AFFF was used during fire training from 2000 to 2012 at the flight line ramp (Figure 6-1). An

unknown quantity of AFFF was released during these fire training events.

Based on the nature of the release (during maintenance/routine testing/training) it appears

unlikely AFFF would have been discharged to the ground surface outside of the flight line ramp,

except potentially via runoff to the grassy areas to the southeast of the flight line ramp. PFAS

contamination may have further infiltrated to subsurface soil in the grassy areas in the vicinity of

the flight line ramp. Under such scenarios ground disturbing activities in these areas could result

in site or construction worker exposure to PFAS via inhalation of dust or ingestion of exposed

surface soil, or construction worker exposure to PFAS via inhalation of dust or ingestion of

exposed subsurface soil.

Potential PFAS contamination may have further infiltrated to shallow groundwater, which is

anticipated to follow topography and flow radially toward Mountain Creek Lake, Cottonwood Bay,

and the Diversion Channel.

6.3 AOI 3 Historic Location of Firetruck

The firetruck that was historically located on site was equipped with AFFF. Although no

interviewees recollected AFFF ever being deployed from the firetruck, there t is possible that spills

occurred in that location that were not recorded or recollected. AFFF spills in the historic location

of the firetruck would have infiltrated into soil.

Based on the nature of the possible release, PFAS contamination may have further infiltrated to

subsurface soil through precipitation from rain events. Under such scenarios, ground disturbing

activities in this area could result in site or construction worker exposure to PFAS via inhalation

of dust or ingestion of exposed surface soil, or construction worker exposure to PFAS via

inhalation of dust or ingestion of exposed subsurface soil.

Potential PFAS contamination may have further infiltrated to shallow groundwater, which is

anticipated to follow topography and flow radially toward Mountain Creek Lake, Cottonwood Bay,

and the Diversion Channel.
!5

!5

!5

!5

!5 !5

!5

!5

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

A!

Historic Location 

of Firetruck

Ramp

Fuel Station Hazardous Materials

Storage Building

Wash Rack Peace Prairie Hangar

with AFFF Fire

Suppression System

Peace Prairie

Hangar OWS

Peace Prairie

Wash Rack

Armory

Organizational

Maintenance Shop

Hangar

Vought/LTV

Aerospace

Cottonwood

Creek-Mountain Creek

Lake Watershed

Mountain

Creek Lake

Cottonwood

Bay

Cottonwood Creek

Diversion Channel

AOI 2

AOI 1

AOI 3

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:9,600

4/28/2020 ­ Figure 6-1 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Areas of Interest

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\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_6-1_Grand_Prairie_AASF_AOIs.mxd

0 400 800 1,600

Feet

Legend

Area of Interest

Potential PFAS Release

No Suspected Release

Approximate Facility

Boundary per TX ARNG

Water Body

River/Stream

Surface Water Flow

Direction

Inferred Groundwater Flow

Direction

!5 Industrial Well

A! Monitor Well

23
Media

SOURCE PATHWAY RECEPTOR

AOI 1

AOI 2

AOI 3

AFFF release

during AFFF fire

extinguisher testing/

training at the wash

rack and flight line

ramp, and storage

of AFFF in the Haz.

Materials Storage

Building, the Fuel

Station, and the

Firetruck

PFAS in

Surface Soil

near AOIs

PFAS in

Subsurface

Soil via soil

infiltration

and from

leaks in

drains,

OWS, and

underground

piping

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

particulate

Surface Soil

at AOI

Surface

Water/

sediment

Subsurface

Soil

Shallow

Groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors:

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

Site

Worker

Construction

Worker Resident Trespasser/Recreational User

Site

Worker

Construction

Worker Resident Trespasser/

Recreational User

/ / /

/ /

LEGEND

/ /

/ / /

Figure 6-2

Preliminary Conceptual Site Model, AOI 1, 2, and 3

Potential

Off-Facility

Source Not

under

Control of

ARNG

/

/

/

/

/

/ /

/

/

Note:

1. The residential receptor

refers to an off-facility

receptor.

/

24
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

25

7. Conclusions

Three AOIs were identified at Grand Prairie AASF during the PA (Figure 7-1).

7.1 Findings

Based on interviews with current AASF personnel, reported historical AFFF releases are

associated with the AFFF fire extinguisher testing/training at the wash rack and flight line ramp,

and AFFF was stored at the hazardous materials storage building, in Tri-MaxTM units at the fuel

stations, and in the old firetruck. These indicate the potential for PFAS contamination in surface

and subsurface soil to intercept one or more receptors. No evidence of other accidental or

incidental spills or leaks from AFFF storage containers/areas were identified during the site visit.

The remaining buildings associated with the AASF are not equipped with or store AFFF. The

findings of potential AFFF release are summarized in Table 7-1 below.

Table 7-1: AOIs at Grand Prairie AASF

Area of Interest Description Used by Release Dates

AOI 1 Releases during AFFF fire extinguisher

testing/training with mobile carts at the

wash rack; discharged to OWS, and

then to sanitary sewer system or to the

street, then to Cottonwood Bay,

depending on the position of a diverter

valve. AFFF stored in the hazardous

materials storage building and in TriMaxTM units at the Fuel Station have

been added to AOI 1 because of the

potential for AFFF spills in those areas.

TXARNG 2000-2012

AOI 2 Releases during AFFF fire extinguisher

testing/training with mobile carts at the

ramp/taxiway. Surface runoff could

potentially migrate to surrounding

grassy areas.

TXARNG 2000-2012

AOI 3 AFFF was stored in the firetruck

historically located in the southern part

of the facility. Although there are no

recorded uses of AFFF in the area,

there is the possibility of leaking in the

area.

TXARNG Unknown

7.2 Uncertainties

Available information sources were investigated during this PA to determine the potential for

PFAS-containing materials to have been present, used, or released at the facility. Historically,

documentation of PFAS use was not required because PFAS were considered benign. Therefore,

records were not typically kept by the facility or available during the PA on the use of PFAS in

training, firefighting, or other non-traditional activities, or on its disposal.

The conclusions of this PA are based on all available information, including: previous

environmental reports, EDRsTM, observations made during the VSI, and interviews. Interviews of
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

26

personnel with direct knowledge of a facility generally provided the most useful insights regarding

a facility's historical and current PFAS-containing materials. Sometimes the provided information

was incomplete. Gathered information has a degree of uncertainty due to the absence of written

documentation, the limited number of personnel with direct knowledge due to staffing changes,

the time passed since PFAS was first used (1969 to present), and a reliance on personal

recollection. Inaccuracies may arise in potential PFAS release locations, dates of release, volume

of releases, and the concentration of AFFF used. There is also a possibility the PA has missed a

source of PFAS, as the science of how PFAS may enter the environment continually evolves.

In order to minimize the level of uncertainty, readily available data regarding the use and storage

of PFAS were reviewed, current personnel were interviewed, multiple persons were interviewed

for the same potential source area, and potential source areas were visually inspected.

Table 7-2 summarizes the uncertainties associated with the PA:

Table 7-2: Uncertainties

Area of Interest Source of Uncertainty

AOI 1 The position of the diverter valve at the OWS

during AFFF training and maintenance

activities is unknown, so it is unclear if

wastewater flowed to the sanitary sewer or to

surface water during these activities.

AOI 2 The flow path of AFFF used for fire training on

the flight line ramp is unknown. It is assumed

that wastewater would flow to nearby grassy

areas.

7.3 Potential Future Actions

Based on the documented absence (1989-present) of the release of PFAS-containing materials

at the AASF Hangar and Armory, evidence does not indicate that current or former TXARNG

activities in these areas contributed PFAS contamination to soil, groundwater, surface water, or

sediment at Grand Prairie AASF. The AASF Hangar and Armory will not move forward in the

CERCLA process.

Interviews (covering 1989 to present) indicate that releases during AFFF fire extinguisher

testing/training in the wash rack area (AOI 1) and flight line ramp (AOI 2) may have resulted in

potential PFAS releases identified during the PA. Additionally, AFFF stored in the hazardous

materials storage building and fuel station (AOI 1) and at the old firetruck (AOI 3) may have

resulted in AFFF spills that occurred unreported. Based on the preliminary CSM developed for

the AOIs, there is potential for receptors to be exposed to PFAS contamination in soil at the AOIs.

Table 7-3 summarizes the rationale used to determine if the AOIs should be considered for further

investigation under the CERCLA process and undergo an SI.

ARNG will evaluate the need for an SI at AOIs 1, 2, and 3 at Grand Prairie AASF based on the

presence of a PFAS release, possible receptors, the migration potential of PFAS contamination

to receptors, and the availability of resources.
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

27

Table 7-3: Rationale

Area of

Interest

AOI

Location

Rationale Potential

Future Action

AOI 1:

Wash

Rack,

Hazardous

Materials

Storage

Building,

and Fuel

Station

32°43'57.0"N;

96°58'40.7"W

32°43'56.3"N;

96°58'42.7"W

32°43'56.0"N; 

96°58'39.5"W

Releases during AFFF fire extinguisher

testing/training with mobile carts at the

wash rack; discharged to OWS, and then to

either the sanitary sewer system or to the

street, which would then flow via surface

water flow to Cottonwood Bay. There is also

potential for releases to have occurred at

the hazardous materials storage building

and at the fuel station. Releases at the

hazardous materials storage building would

have likely been washed to the wash rack,

and releases at the fuel station would likely

infiltrate into soil.

Proceed to an

SI, focus on

soil and

shallow

groundwater

AOI 2:

Flight Line

Ramp

32°43'53.5"N;

96°58'42.4"W

Releases during AFFF fire extinguisher

testing/training with mobile carts at the

ramp/taxiway. Surface runoff could

potentially migrate to surrounding grassy

areas.

Proceed to an

SI, focus on

soil and

shallow

groundwater

AOI 3:

Historic

Location of

Firetruck

32°43'45.7"N; 

96°58'40.5"W

There is potential for AFFF to have leaked

into the soil surrounding the historic location

of the firetruck.

Proceed to an

SI, focus on

soil and

shallow

groundwater
Historic Location 

of Firetruck

Ramp

Fuel Station Hazardous Materials

Storage Building

Wash Rack

Peace Prairie Hangar

with AFFF Fire

Suppression System

Peace Prairie

Hangar OWS

Peace Prairie

Wash Rack

Armory

Organizational

Maintenance Shop

Hangar

Vought/LTV

Aerospace

Mountain

Creek Lake

Cottonwood

Bay

Cottonwood Creek

Diversion Channel

AOI 2

AOI 1

AOI 3

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

MC

4/28/2020

4/28/2020

NOTES Preliminary Assessment for PFAS at Grand Prairie AASF, TX

1:9,600

4/28/2020 ­ Figure 7-1 PM RG 4/28/2020

12420 Milestone Center Drive

Germantown, MD 20876

Summary of Findings

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\TX\Grand_Prairie_Figures\Grand_Prairie_PA_Figures\Fig_7-1_Grand_Prairie_AASF_Summary.mxd

0 400 800 1,600

Feet

Legend

Area of Interest

Potential PFAS Release

No Suspected Release

Approximate Facility

Boundary per TX ARNG

Water Body

River/Stream

28
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

29

8. References

Geo-Marine, Inc (GMI). July 2002. Draft Site Assessment Survey (SAS). Texas Army National

Guard (TXARNG) Dallas Naval Air Station (DNAS) Facilities. Grand Prairie, Texas.

GMI. December 2003. Letter Report. Phase II Environmental Confirmation Sampling and

Analysis at the Texas Army National Guard Dallas Naval Air Station Aviation Support Facility.

Grand Prairie, TX.

National Oceanic and Atmospheric Administration (NOAA). 2019. Dallas/Fort Worth Climatology.

https://www.weather.gov/fwd/dfwclimo. Accessed 8 May 2019.

Tetra Tech NUS, Inc. (TtNUS). 2001. RCRA Facility Investigation (RFI) Report for Category A

Naval Air Station Dallas.

United States Environmental Protection Agency (USEPA). 1991. Guidance for Performing

Preliminary Assessments under CERCLA. EPA/540/G-91/013. September 1991.

USEPA. 2018. Superfund Site: Bio-Ecology Systems Inc.

https://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0602464. Accessed 15 May 2019.
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Appendix A

Data Resources
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Data resources will be provided separately on CD. Data resources for Grand Prairie AASF

include:

Previous Investigations Completed

· Naval Air Station, Dallas, Texas. DRAFT Finding of Suitability and Environmental Baseline

Survey to Modify Lease NOY(R)-44881. April 1997.

· Geo-Marine, Inc. July 2002. Draft Site Assessment Survey (SAS). Texas Army National

Guard (TXARNG) Dallas Naval Air Station (DNAS) Facilities. Grand Prairie, Texas.

· Geo-Marine, Inc. December 2003. Final Phase II Environmental Confirmation Sampling and

Analysis at the TXARNG DNAS Aviation Support Facility. Grand Prairie, Texas.

· Freese and Nichols, Inc. September 2018. Environmental Condition of Property Phase I

Environmental Site Assessment Singapore Air Force Lease Property. Prepared for Texas

Military Department.

Miscellaneous Data Resources

· EDRTM Aerial Photo Decade Package, December 2019. Grand Prairie AASF, 1013 Lakecrest

Dr, Grand Prairie, TX 75051.

· EDRTM Radius Map Report with GeoCheck, December 2019. Grand Prairie AASF, 1013

Lakecrest Dr, Grand Prairie, TX 75051.

· EDRTM Certified Sanborn Map Report, December 2019. Grand Prairie AASF, 1013 Lakecrest

Dr, Grand Prairie, TX 75051.

· McCowan, Leon. Texas Army National Guard Environmental Spill Report. 2003.

· Lease Agreement between the County of Dallas and Texas National Guard Armory Board.

1988.
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Appendix B

Preliminary Assessment Documentation
PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Appendix B.1

Interview Records






PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Appendix B.2

Visual Site Inspection Checklists

PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Appendix B.3

Conceptual Site Model Information



PFAS Preliminary Assessment Report

Grand Prairie AASF, TX

Appendix C

Photographic Log
Preliminary Assessment Report

Grand Prairie AASF Grand Prairie, TX

Perfluorooctane-Sulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

AECOM

APPENDIX C – Photographic Log

Army National Guard, Preliminary

Assessment for PFAS Grand Prairie AASF Grand Prairie, Texas

Photograph No. 1

Description:

April 23, 2019

Facing NE, looking out at the 

Fueling Station. Historically, 

Tri-Max fire extinguishers 

were stationed at the fuel 

station (but never used). 

Photograph No. 2

Description: 

April 23, 2019

Facing west, looking at the 

Ramp/Flightline Area where 

Tri-Max fire extinguishers 

were historically used for fire 

training purposes. 
Preliminary Assessment Report

Grand Prairie AASF Grand Prairie, TX

Perfluorooctane-Sulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

AECOM

APPENDIX C – Photographic Log

Army National Guard, Preliminary

Assessment for PFAS Grand Prairie AASF Grand Prairie, Texas

Photograph No. 3

Description:

April 23, 2019

Facing SE, looking at flight 

lines with existing fire 

extinguishers (non-AFFF).

Photograph No. 4

Description: 

April 23, 2019

Facing north, looking at the 

bulk chemical storage 

building. Historically, 30 – 5 

gallon buckets of 3% AFFF 

was stored in this building. 
Preliminary Assessment Report

Grand Prairie AASF Grand Prairie, TX

Perfluorooctane-Sulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

AECOM

APPENDIX C – Photographic Log

Army National Guard, Preliminary

Assessment for PFAS Grand Prairie AASF Grand Prairie, Texas

Photograph No. 5

Description:

April 23, 2019

Looking inside of the bulk 

chemical storage building. 

Historically, 30 – 5 gallon 

buckets of 3% AFFF was 

stored in this building. No 

floor drains were observed 

inside the storage area. 

Photograph No. 6

Description: 

April 23, 2019

Facing SW, looking at 

location where old fire truck 

with AFFF was located. 

Historically a small secondary 

containment/spill pad was 

located underneath the fire 

truck. The historic fire truck 

was never used, and was later 

turned in.