FINAL

Preliminary Assessment Report

Barrigada Readiness Center

Guam

Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic Acid 

(PFOA) Impacted Sites

ARNG Installations, Nationwide

January 2021

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
PFAS Preliminary Assessment Report

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Table of Contents

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

1. Introduction ........................................................................................................................ 4

1.1 Authority and Purpose .............................................................................................. 4

1.2 Preliminary Assessment Methods ............................................................................. 4

1.3 Report Organization .................................................................................................. 5

1.4 Facility Location and Description............................................................................... 5

1.5 Facility Environmental Setting ................................................................................... 6

1.5.1 Geology ......................................................................................................... 6

1.5.2 Hydrogeology ................................................................................................. 6

1.5.3 Hydrology ....................................................................................................... 6

1.5.4 Climate ........................................................................................................... 7

1.5.5 Current and Future Land Use ......................................................................... 7

2. Fire Training Areas ........................................................................................................... 11

3. Non-Fire Training Areas ................................................................................................... 12

3.1 Fire Extinguisher Maintenance Area ....................................................................... 12

3.2 Dining Facility ......................................................................................................... 12

4. Emergency Response Areas ............................................................................................ 14

5. Adjacent Sources ............................................................................................................. 15

5.1 NCTAMS Barrigada and Naval Activities ................................................................. 15

6. Preliminary Conceptual Site Model .................................................................................. 17

6.1 AOI 1: Fire Extinguisher Maintenance Area ............................................................ 17

7. Conclusions ..................................................................................................................... 20

7.1 Findings .................................................................................................................. 20

7.2 Uncertainties ........................................................................................................... 20

7.3 Potential Future Actions .......................................................................................... 21

8. References ...................................................................................................................... 23
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Tables

Table ES-1 AOIs at Barrigada Readiness Center

Table 7-1 AOIs at Barrigada Readiness Center

Table 7-2 Summary of Uncertainties

Table 7-3 PA Findings Summary

Figures

Figure ES-1 Summary of Findings

Figure ES-1 Preliminary Conceptual Site Model, Barrigada Readiness Center, Guam

Figure 1-1 Facility Location

Figure 1-2 Groundwater Features

Figure 1-3 Surface Water Features

Figure 3-1 Non-Fire Training Area

Figure 5-1 Adjacent Sources

Figure 6-1 Area of Interest

Figure 6-2 Preliminary Conceptual Site Model, Barrigada Readiness Center, Guam

Figure 7-1 Summary of Findings

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
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Acronyms and Abbreviations

°F degrees Fahrenheit

AECOM AECOM Technical Services, Inc.

AFFF aqueous film forming foam

amsl above mean sea level

AOI area of interest

ARNG Army National Guard

CAFS compressed air foam system

CERCLA Comprehensive Environmental Response, Compensation, and Liability

Act

CFR Code of Federal Regulations

CSM conceptual site model

DA United States Department of the Army

DFAC dining facility

EDR TM Environmental Data Resource, Inc. TM

FTA fire training area

GUARNG Guam Army National Guard

HA Health Advisory

NCTAMS Naval Computer and Telecommunications Area Master Station

PA Preliminary Assessment

PFAS per- and poly-fluoroalkyl substances

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

SI Site Inspection

UCMR3 Unregulated Contaminant Monitoring Rule 3

US United States

USACE United States Army Corps of Engineers

USEPA United States Environmental Protection Agency

VSI visual site inspection
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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 Barrigada Readiness Center (also referred to as

the “facility”) in Barrigada, Guam, to assess potential PFAS release areas and exposure pathways

to receptors. Barrigada Readiness Center is leased from the United States (US) Navy by the

Guam ARNG (GUARNG), and occupation of the property by GUARNG began in 2001. 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 site visit on 20 November 2019 and completed visual site inspections (VSIs) at

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

disposed;

· Interviewed current GUARNG personnel during the site visit;

· Identified Area(s) of Interest (AOIs) and developed a preliminary conceptual site model (CSM)

to summarize potential source-pathway-receptor linkages of potential PFAS in soil,

groundwater, surface water, and sediment for each AOI.

One AOI related to a potential PFAS release was identified at Barrigada Readiness Center. The

AOI is shown on Figures ES-1 and described in Tables ES-1 below.

Table ES-1: AOIs at Barrigada Readiness Center

Area of Interest Name Used by Potential Release Dates

AOI 1 Fire Extinguisher

Maintenance Area

GUARNG Between 01-17 June 2016

and early 2019

Based on the documented release concerning the aqueous film forming foam at the facility, there

is potential for exposure to PFAS contamination in media at or near the facility. The preliminary

CSM for the Barrigada Readiness Center, which presents the potential receptors and media

impacted, 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 PFAS were

detected in a public water system above the USEPA’s lifetime Health Advisory (HA) within 5 miles

of the facility. The HA is 70 parts per trillion for PFOS and PFOA, individually or combined. The

affected public water system is the GU Waterworks Authority – Northern System, which had

detections of PFOS in groundwater ranging from 41 to 410 parts per trillion. The UCMR3 dataset

is located in Appendix A. 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.
Aviation Operations Facility

AOI 1

DFAC

Fire Extinguisher

Maintenance Area

Building 830

Bay 3

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SOURCE PATHWAY RECEPTOR

AOI 1

Fire 

Extinguisher 

AFFF Spill or 

Release

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ 

Infiltration

Airborne Soil 

particulate

Surface Soil 

at AOI

Surface 

Water/ 

sediment

Subsurface 

Soil

Groundwater

Source Release 

Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors: 

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

LEGEND

Figure ES-2

Preliminary Conceptual Site Model

Barrigada Readiness Center, Guam

PFAS in 

Surface Soil/

Surface 

Water

/ / / /

/ / / /

/ / / /

/ / / /

/ / / /

NOTES

1. The resident and recreational users refer to 

off-site receptors.

2. Inhalation of dust for off-site receptors is likely 

insignificant. 

3. UCMR3 data for municipal drinking water 

exceeded the HA of 70 parts per trillion for 

PFOS. 

Site 

Worker3

Construction 

Worker Resident1,2,3 Trespasser/Recreational User1

Site 

Worker3

Construction 

Worker Resident1,2,3 Trespasser/Recreational User1

3
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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 facilities that

used per- and poly-fluoroalkyl substances (PFAS) (a suite of related chemicals), primarily in the

form of aqueous film forming foam (AFFF) released as part of firefighting activities, although other

PFAS sources 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. PFAS

formulations contain highly diverse mixtures of compounds. Thus, the fate of these PFAS

compounds in the environment varies. The regulatory framework at both federal and state levels

continues to evolve. The US Environmental Protection Agency (USEPA) issued a lifetime Drinking

Water Health Advisory (HA) for PFOA and PFOS in May 2016, but there are currently no

promulgated national standards regulating PFAS in drinking water. The HA is 70 parts per trillion

for PFOS and PFOA, individually or combined.

This report presents findings of a PA for PFAS-containing materials at Barrigada Readiness

Center (also referred to as the “facility”) in Barrigada, Guam 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 [CFR] Part 300), and Army requirements and guidance (US Department of

the Army [DA], 2016; DA, 2018).

This PA documents potential locations where PFAS-containing materials are stored and have the

potential to be released into the environment at or adjacent to the Barrigada Readiness Center.

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 site visit on 20 November 2019 and completed visual site inspections (VSIs) at

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

disposed;

· Interviewed current Guam ARNG (GUARNG) personnel during the site visit;
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· Identified Area(s) of Interest (AOIs) and developed a preliminary conceptual site model (CSM)

to summarize potential source-pathway-receptor linkages of potential PFAS in soil,

groundwater, surface water, and sediment for each AOI.

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 as follows:

· 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 fire training areas (FTAs) at the facility

identified during the site visit.

· Section 3 – Non-Fire Training Areas: describes other locations of potential PFAS releases

at the facility identified during the site visit.

· Section 4 – Emergency Response Areas: describes areas of potential PFAS release at the

facility, specifically in response to emergency situations.

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

facility that are not under the control of ARNG.

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

transport and receptors at the facility.

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

uncertainties 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

Barrigada Readiness Center is in the east-central portion of Guam (Figure 1-1). The facility falls

within Barrigada off Route 16, and it is bordered to the north and east by the Naval Computer and

Telecommunications Area Master Station (NCTAMS) Barrigada, to the west by Tiyan High School,

and to the south by residential areas. The facility is approximately 60 acres.

Barrigada Readiness Center provides training and maintenance for the various units that support

the GUARNG. The facility consists of office areas, gas station, maintenance shop, motor pool, a

hangar, and storage buildings. In 1950, under the Organic Act of 1950, the property was

quitclaimed by the Naval Government of Guam and transferred to the US Navy (Ogden, 1996).

The facility property was owned by the US Navy as part of NCTAMS Barrigada, until it was leased

to GUARNG in 2001. Leasing records were requested but were unavailable. According to

interviewed personnel, an additional 27 acres was acquired in 2016 and is shown on Figure 1-1

as the northeastern portion of the facility; GUARNG did not occupy the hangar, also called

“Aviation Operations Facility”, prior to June 2016. Historical aerial imagery shows that the hangar

was constructed between 2011 and 2014. The hangar does not contain any fire suppression

system.
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1.5 Facility Environmental Setting

The Barrigada Readiness Center is located approximately 2.5 miles south of Tumon Bay.

Throughout the facility, the natural terrain slopes towards south towards the southern coastline of

Guam, ranging from a maximum elevation of approximately 250 to 310 feet above mean sea level

(amsl).

1.5.1 Geology

Guam has four major physiographic areas: limestone plateau, volcanic uplands, interior basin,

and coastal lowlands with alluvial valley floors (Tracey et al., 1964). Barrigada Readiness Center

overlies the limestone plateau, which includes the north plateau, Orote Peninsula, and the fringing

limestone of the southeast coast. The north plateau is relatively flat and consists of reefassociated limestone that has been raised above sea level and tilted to the southwest. Sinkholes

range from a few feet to approximately 75 feet deep over most of the limestone plateau.

The Barrigada formation is a white, relatively homogeneous, massive, detrital limestone having a

characteristic assemblage of large foraminifera. The Barrigada limestone is the principal rock of

northern Guam and underlies most of the northern half of the island; it unconformably overlies

Alutom volcanics in some areas and is unconformably overlain by variably thick sequences of

Mariana limestone (Figure 1-2). In many places, the Barrigada limestone is brecciated and

ranges from compact and well-lithified to extremely friable. The permeability of the limestone is

relatively high and contains fresh basal ground water up to approximately 7 feet above amsl

(Ogden, 1996).

1.5.2 Hydrogeology

Guam can be divided into two hydrogeologic provinces. Groundwater in northern Guam is

contained in permeable limestone, while the groundwater in southern Guam is contained in

volcanic rock of low permeability. Barrigada Readiness Center is part of the northern Guam

hydrogeologic province and overlays the “northern lens” aquifer situated in the Barrigada

limestone. The term “northern lens” refers to the lens that develops as rainfall percolates through

the surface soil to the underlying, highly porous limestone and accumulates on and displaces

denser water.

The Barrigada limestone is characterized by high porosity due to the dissolution and cavernous

features. Freshwater flows toward areas of discharge at the shore. The water table is several

hundred feet above amsl in the interior and declines to sea level at the coast. Recharge of the

aquifer increases the volume of the freshwater lens and lowers the elevation of the

freshwater/saltwater interface. Under the provisions of the Safe Drinking Water Act, the

groundwater lens of northern Guam was designated a “principal sole source aquifer” (Ogden,

1996).

An EDRTM report conducted a well search for a 1-mile radius surrounding the facility (Appendix

A). Using additional online resources, such as state and local Geographic Information System

databases, wells were researched to a 4-mile radius of the facility. There are no drinking water

wells on the facility, but multiple production wells surround the facility to the north, northeast, and

southwest. Based on the south/southeastern inferred groundwater direction, some of these

production wells may be potentially downgradient from the facility. Groundwater features are

presented in Figure 1-2.

1.5.3 Hydrology

Despite the large amount of rainfall that occurs on Guam, there are no perennial streams located

on or in the vicinity of the facility because of high infiltration rates into the underlying limestone.
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The entirety of the facility lies within the Fonte River-Frontal Hagatna Bay Watershed (Figure 1-

3). The USEPA Unregulated Contaminant Monitoring Rule 3 (UCMR3) data indicated that

PFOS/PFOA were detected in the GU Waterworks Authority – Northern System above the USEPA

HA within a 5-mile radius of the facility. The detections of PFOS in this public water system ranged

from 41 to 410 parts per trillion, and the UCMR3 dataset is located in Appendix A. The HA is 70

parts per trillion for PFOS and PFOA, individually or combined. 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.

1.5.4 Climate

Guam’s climate is characterized by mild temperatures, easterly trade winds year-round, and

humid conditions typical of the tropics. Guam has two seasons: rainy (between July and

November) and dry (between January and May). The temperature ranges from mid to high-80s

degrees Fahrenheit (°F), with temperatures decreasing at higher elevations. Humidity on Guam

ranges from approximately 75 to 100 percent. Annual rainfall ranges from 80 inches in the coastal

lowland areas to 100 inches in the interior upland of southern Guam (Ogden, 1996).

1.5.5 Current and Future Land Use

Current Barrigada Readiness Center operations include training and maintenance for the various

units that support the GUARNG. In addition, a medivac unit uses the hangar in the northern

portion of the property. GUARNG currently leases the property from the US Navy, which borders

the property to the north and east. The town of Barrigada also abuts the Readiness Center to the

south and west.

Reasonably anticipated future land use is not expected to change from the current land use

described above.
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2. Fire Training Areas

No FTAs were identified within the facility during the PA through interviews (Appendix B), EDRTM

reports (Appendix A), or from observations made during the VSI. The personnel interviewed had

institutional knowledge spanning from 2015 to present. Information regarding the timespan

between 2001 (beginning of property lease) and 2015 was not available.
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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. Four non-FTAs were

identified during the PA. Descriptions of the non-FTAs are presented below, and locations of the

non-FTAs are shown on Figure 3-1.

3.1 Fire Extinguisher Maintenance Area

Between the 1st and 17th of June 2016, new Tri-Max TM compressed air foam systems (CAFSs)

were issued to GUARNG, and personnel received training on the new systems. Training was

conducted in the northern grassy area of the hangar. As part of the training, personnel were

instructed on how to load the Tri-MaxTM and were shown the various parts of the extinguisher. In

addition, hands-on demonstrations were conducted on how to properly use the Tri-MaxTM. Based

on interviews, there was a large amount of foam released during the hands-on demonstrations.

One of the interviewees maintained that the Tri-MaxTM CAFSs were filled with soap and not AFFF

during the demonstrations because the AFFF material had not yet arrived. According to

interviewed personnel, GUARNG did not occupy the hangar, also called “Aviation Operations

Facility”, prior to June 2016 and AFFF was only acquired after their arrival. Although it is unclear

whether soap or AFFF was used in the training exercises, no other training or use with the TriMaxTM CAFSs was conducted after the DA issued the memorandum “Limiting Use of Aqueous

Film Forming Foam” on 29 June 2016 (DA, 2016).

In early 2019, the Tri-Max TM CAFSs were emptied of AFFF and moved to a 55-gallon drum plus

a 5.5-gallon drum. To empty the Tri-Max TM, the personnel interviewed stated that they siphoned

the AFFF and then used a shop vac once the siphoning was no longer productive. Absorbent

pads were placed around the CAFSs and drums during the siphoning process to catch any AFFF

spills. The shop vac was cleaned with the spigot located on the southeast end of the hangar, and

the rinse water was allowed to drain naturally. After being cleaned, the shop vac was disposed of

in regular municipal waste. The used absorbent pads were placed in a single 55-gallon drum and

stored with the AFFF drums inside Building 830, a storage shed located also in the grassy area

of the hangar next to where training and maintenance activities were conducted. The AFFF and

used absorbent pad drums inside Building 830 were sitting on top of spill containment pallets, and

no spills were observed during the VSI (see Photos 5-7 in Appendix C). The empty and filled

CAFSs were stored in Bay 3 of the hangar when not in use. Two empty CAFSs were observed

inside Bay 3 during the VSI (see Photo 1 in Appendix C). Both storage locations, Bay 3 and

Building 830, are shown on Figure 3-1.

3.2 Dining Facility

The dining facility (DFAC) is located on the southwest portion of Barrigada Readiness Center. The

DFAC is equipped with an Ansul R-102 wet chemical fire suppression system. The wet chemical

agent used in the system is composed of a mixture of organic salts and reportedly does not

contain PFAS (Ansul, 2017). The DFAC is not considered to be a potential release area of PFAS.
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4. Emergency Response Areas

No instances of emergency responses were identified at Barrigada Readiness Center during the

PA, based on the institutional knowledge of the interviewees (spanning from 2015 to present).

The facility relies on the local fire department or the nearby federal fire department for emergency

needs. There has been no need for response as of the date of the PA interviews. Interviewees

highlighted their history of zero incidents at the facility (Appendix B.1).
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5. Adjacent Sources

One potential off-facility source of PFAS adjacent to Barrigada Readiness Center, not under the

control of the GUARNG, was identified during the PA. A description of the adjacent source is

presented below, and the adjacent source is shown on Figure 5-1.

5.1 NCTAMS Barrigada and Naval Activities

NCTAMS Barrigada is located adjacent to the Barrigada Readiness Center. The US Navy is in

the process of performing a focused SI for PFAS at NCTAMS; additional information regarding 

the investigation was not available at the time of the PA report. Because portions of the facility are

located both downgradient and side gradient to areas of NCTAMS, it is possible that NCTAMS is

a potential off-facility source of PFAS.

During document reviews, a former fire station was identified within a Naval Activities property

site (Ogden, 1996). The history and the extent of AFFF use, if any, at the former fire station is

unknown, but the approximate location of the former fire station is located about 10 miles

southwest of the facility. Review of the EDRTM did not reveal other likely PFAS sources near the

facility.
NCTAMS

Barrigada

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Potential PFAS Release

Facility Boundary

Water Body

Wetland

Adjacent Sources

12420 Milestone Center Drive

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Antonio B. Won Pat

International Airport

Barrigada

Heights

Asbeco

Mangilao

Barrigada

Figure 5-1

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6. Preliminary Conceptual Site Model

Based on the PA findings, one AOI was identified at Barrigada Readiness Center. The AOI location

is shown on Figure 6-1. The following sections describe the CSM components and the specific

preliminary CSM developed for the AOI. 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.

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 (National Ground Water

Association, 2018). Receptors at Barrigada Readiness Center include site workers, construction

workers, trespassers, and off-facility residents. The preliminary CSM for Barrigada Readiness

Center indicates which specific receptors could potentially be exposed to PFAS. The preliminary

CSM for AOI 1 is shown in Figure 6-2.

6.1 AOI 1: Fire Extinguisher Maintenance Area

AOI 1 contains the Tri-MaxTM training area, Building 830, and Bay 3, where AFFF was stored

and/or may have been released during filling and emptying of the Tri-Max TM CAFSs. The area

where the Tri-MaxTM training was conducted is grassy, while Building 830 and Bay 3 are paved.

Ground-disturbing activities in release areas could result in site worker, construction worker, and

trespasser exposure to potential PFAS contamination via inhalation of dust or ingestion of surface

soil. PFAS may have also infiltrated from surface soil to the subsurface, and ground-disturbing

activities to subsurface soil could result in construction worker exposure.

The surface water/ sediment exposure pathway is considered incomplete because there are no

perennial streams or wetlands at the facility. The facility overlies a highly porous limestone

plateau, so all surface water runoff from precipitation percolates into the ground (Earth Tech, Inc.,

2000).

PFAS are water soluble and can migrate readily from soil to groundwater via leaching. No drinking

water wells exist at the facility; however, drinking water at Barrigada Readiness Center is

resourced from several public drinking water wells that may be located hydraulically downgradient

from the facility. Based on the UCMR3 data, a public water system (GU Waterworks Authority –

Northern System) exceeded the HA of 70 parts per trillion for PFOS in groundwater wells within

5 miles of the facility (Appendix A). Therefore, site workers and off-facility residents may be

potentially exposed to contaminated groundwater attributable to the facility. The groundwater

depth is at least 250 feet below ground surface, so construction workers are unlikely to encounter

shallow groundwater (Earth Tech, Inc., 2000).
!C(

!C(

!C(

!C(

!C(

!C(

!C( !C(

!C( !C(

!C(

Aviation Operations Facility NCTAMS

Barrigada

Building 830

DFAC Bay 3

Fire Extinguisher

Maintenance Area

AOI 1

Mataguac Spring-Frontal

Pacific Ocean Watershed

Fonte River-Frontal

Hagatna Bay Watershed

Apra

Harbor-Phillipine

Sea Watershed

0 1,100 2,200 4,400

Feet

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Area of Interest

Potential PFAS Release

No Suspected Release

Facility Boundary

Water Body

Wetland

River/Stream

Surface Water Flow Direction

Inferred Groundwater Flow Direction

!C( Production Well

Area of Interest

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SOURCE PATHWAY RECEPTOR

AOI 1

Fire 

Extinguisher 

AFFF Spill or 

Release

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ 

Infiltration

Airborne Soil 

particulate

Surface Soil 

at AOI

Surface 

Water/ 

sediment

Subsurface 

Soil

Groundwater

Source Release 

Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors: 

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

LEGEND

Figure 6-2

Preliminary Conceptual Site Model

Barrigada Readiness Center, Guam

PFAS in 

Surface Soil/

Surface 

Water

/ / / /

/ / / /

/ / / /

/ / / /

/ / / /

NOTES

1. The resident and recreational users refer to 

off-site receptors.

2. Inhalation of dust for off-site receptors is likely 

insignificant. 

3. UCMR3 data for municipal drinking water 

exceeded the HA of 70 parts per trillion for 

PFOS. 

Site 

Worker3

Construction 

Worker Resident1,2,3 Trespasser/Recreational User1

Site 

Worker3

Construction 

Worker Resident1,2,3 Trespasser/Recreational User1

19
PFAS Preliminary Assessment Report

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7. Conclusions

This report presents a summary of available information gathered during PA efforts on the use

and storage of AFFF and other PFAS-related activities at the Barrigada Readiness Center. The

PA findings are based on the information presented in Appendix A and Appendix B.

7.1 Findings

One AOI related to potential PFAS releases was identified at the Barrigada Readiness Center

during the PA. Figure 7-1 and Table 7-1 present a summary of PA findings.

Table 7-1: AOIs at Barrigada Readiness Center

Area of Interest Name Used by Potential Release Dates

AOI 1 Fire Extinguisher

Maintenance Area

GUARNG Between 01-17 June 2016 and

early 2019

Based on the storage and potential AFFF release at the AOI, there is potential for exposure to

PFAS contamination in media at or near the facility. The preliminary CSM for Barrigada Readiness

Center, which presents the potential receptors and media impacted, is shown on Figure 6-2.

7.2 Uncertainties

A number of 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 disposition.

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

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

a facility’s historical and current PFAS-containing materials. 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 were 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.

Comprehensive information on all industrial practices that may potentially be sources of PFAS is

incomplete. Therefore, this PA may not identify all potential PFAS sources.

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

of PFAS were reviewed, retired and 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.
PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

21

Table 7-2: Summary of Uncertainties

Location Source of Uncertainty

AOI 1 – Fire

Extinguisher

Maintenance Area

The exact details of the training practice with the extinguisher were

not definitive. It is unclear when the Tri-MaxTM CAFSs were filled

with AFFF and whether training was conducted with AFFF or soap.

General The personnel interviewed had institutional knowledge spanning

from 2015 to present. Information regarding the timespan between

2001 (beginning of property lease) and 2015 was not available.

7.3 Potential Future Actions

The degree of uncertainties associated with the interviews and data collected during the PA

indicates that former GUARNG activities may have resulted in potential PFAS releases at the one

AOI identified during the PA. Based on the preliminary CSM developed for the AOI, there is

potential for receptors to be exposed to PFAS contamination in soil, subsurface soil, and

groundwater at this AOI. Table 7-3 summarizes the rationale used to determine if the AOI should

be considered for further investigation under the CERCLA process and undergo an SI.

Table 7-3: PA Findings Summary

Area of Interest AOI Location Rationale Potential Future

Action

AOI 1 – Fire

Extinguisher

Maintenance Area

13°28’33.78”N

and

144°48’53.11”E

Training and maintenance of TriMax TM CAFSs.Proceed to an SI;

focus on soil and

groundwater.

ARNG will evaluate the need for an SI at Barrigada Readiness Center based on the potential

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

contamination to receptors.
Aviation Operations Facility

AOI 1

DFAC

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Summary of Findings

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8. References

Ansul. 2017. Data Sheet R-102 Restaurant Fire Suppression Systems.

Department of the Army (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.

Earth Tech, Inc. 2000. Technical Memorandum Phase 2B Soil Sampling, Abbreviated Remedial

Investigation, Point of Interest (POI)-03, Former NCTAMS Barrigada Disposal Areas,

Guam. July.

Ogden Environmental and Energy Services Co., Inc (Ogden). 1996. Environmental Baseline

Survey Final for Naval Activities Various Sites Volume 1, Guam, Mariana Islands.

November.

National Ground Water Association, 2018. Groundwater and PFAS: State of Knowledge and

Practice. January.

Tracey, J.I., Jr., S.O. Schlanger, J.T. Stark, D.B. Doan, and H.G. May, 1964. General Geology of

Guam, USGS Professional Paper 403-A.

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

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

Barrigada Readiness Center, Guam

Appendix A

Data Resources
PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

Data Resources will be provided separately on CD. Data Resources for Barrigada Readiness 

Center, Guam include:

Barrigada Readiness Center UCMR3

• 2015-2017 Barrigada Readiness Center UCMR3 Data

Barrigada Readiness Center EDRTM Report

• 2020 EDR Aerial Photo Decade Package

• 2020 EDR ZIP/PLUSTM Report

• 2020 EDR Historical Topo Map Report

Barrigada Readiness Center Environmental Reports

• 1996 Environmental Baseline Survey

• 1998 Environmental Baseline Survey Addendum Report

• 2000 Technical Memorandum Phase 2B Soil Sampling, Abbreviated Remedial Investigation 

POI-03

• 2003 Abbreviated Remedial Investigation Former NCTAMS Barrigada Disposal Areas
PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

Appendix B

Preliminary Assessment Documentation
PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

Appendix B.1

Interview Records




PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

Appendix B.2

Visual Site Inspection Checklists



PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

Appendix B.3

Conceptual Site Model Information



PFAS Preliminary Assessment Report

Barrigada Readiness Center, Guam

Appendix C

Photographic Log
Preliminary Assessment Report

Barrigada Readiness Center

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 Barrigada Readiness Center Guam

Photograph No. 1

Description:

Two CAFS fire extinguishers 

located in Bay 3.

Date Taken:

19 November 2019

Photograph No. 2

Description:

CAFS canister placard

Date Taken:

19 November 2019
Preliminary Assessment Report

Barrigada Readiness Center

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 Barrigada Readiness Center Guam

Photograph No. 3

Description:

CAFS label

Date Taken:

19 November 2019

Photograph No. 4

Description: 

Bldg. 830, currently stores 

Hazardous Waste including 

one 55-gallon drum on AFFF 

and AFFF soaked absorbent 

pads.

Date Taken:

19 November 2019
Preliminary Assessment Report

Barrigada Readiness Center

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 Barrigada Readiness Center Guam

Photograph No. 5

Description:

AFFF from the CAFS, stored 

in Bldg. 830.

Date Taken:

19 November 2019

Photograph No. 6

Description:

5 gallons of used AFFF. 

Located in Bldg. 830.

Date Taken:

19 November 2019
Preliminary Assessment Report

Barrigada Readiness Center

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 Barrigada Readiness Center Guam

Photograph No. 7

Description:

Drum with used absorbent 

pads.

Date Taken:

19 November 2019

Photograph No. 8

Description: 

Area of CAFS training, and 

where AFFF spilled during 

transfer of AFFF from CAFS

to drums.

Date Taken:

19 November 2019
Preliminary Assessment Report

Barrigada Readiness Center

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 Barrigada Readiness Center Guam

Photograph No. 9

Description:

Unused AFFF located inside 

Bay 3 of Bldg. 

Date Taken:

19 November 2019

Photograph No. 10

Description:

Fire suppression system in 

DFAC, Ansul R-102.

Date Taken:

19 November 2019