FINAL

Site Inspection Report

Bismarck Army Aviation Support Facility #1

Bismarck, North Dakota

Site Inspection for Perfluorooctanoic Acid (PFOA), Perfluorooctanesulfonic Acid (PFOS), 

Perfluorohexanesulfonic Acid (PFHxS), Perfluorononanoic Acid (PFNA), Hexafluoropropylene 

Oxide Dimer Acid (HFPO-DA), and Perfluorobutanesulfonic Acid (PFBS)

ARNG Installations, Nationwide

September 2023

Prepared for:

Army National Guard Headquarters

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
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TABLE OF CONTENTS

Page

LIST OF APPENDICES ........................................................................................................... iii

LIST OF FIGURES .................................................................................................................. iv

LIST OF TABLES ......................................................................................................................v

LIST OF ACRONYMS AND ABBREVIATIONS ................................................................... vi

EXECUTIVE SUMMARY ................................................................................................... ES-1

1. INTRODUCTION ........................................................................................... 1-1

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

1.2 Site Inspection Purpose......................................................................... 1-1

2. FACILITY BACKGROUND ........................................................................... 2-1

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

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

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

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

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

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

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

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

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

3. SUMMARY OF AREAS OF INTEREST ........................................................ 3-1

3.1 AOI 1 – Main Hangar ........................................................................... 3-1

3.2 AOI 2 – Fuel Point ............................................................................... 3-2

3.3 AOI 3 – Fuel Truck Parking ................................................................. 3-2

3.4 Adjacent Sources .................................................................................. 3-2

3.4.1 Bismarck Airport Fire Department ......................................... 3-2

3.4.2 Corporate Hangars ................................................................. 3-2

4. PROJECT DATA QUALITY OBJECTIVES ................................................... 4-1

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

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

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

4.4 Analytical Approach ............................................................................. 4-1
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4.5 Data Usability Assessment ................................................................... 4-2

5. SITE INSPECTION ACTIVITIES ................................................................... 5-1

5.1 Pre-Investigation Activities .................................................................. 5-2

5.1.1 Technical Project Planning ..................................................... 5-2

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

5.1.3 Source Water and PFAS Sampling Equipment Acceptability . 5-3

5.2 Soil Borings and Soil Sampling ............................................................ 5-3

5.3 Temporary Well Installation and Groundwater Grab Sampling ............. 5-4

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

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

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

5.7 Laboratory Analytical Methods ............................................................ 5-6

5.8 Deviations from SI UFP-QAPP Addendum .......................................... 5-6

6. SITE INSPECTION RESULTS ....................................................................... 6-1

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

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

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

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

6.3.2 AOI 1 Groundwater Analytical Results .................................. 6-3

6.3.3 Conclusions ........................................................................... 6-3

6.4 AOI 2 ................................................................................................... 6-4

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

7. EXPOSURE PATHWAYS .............................................................................. 7-1

7.1 Soil Exposure Pathway ......................................................................... 7-2

7.1.1 AOI 1 ..................................................................................... 7-2

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

7.1.3 AOI 3 ..................................................................................... 7-2

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

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

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

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

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

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

7.3.2 AOI 2 ..................................................................................... 7-5
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7.3.3 AOI 3 ..................................................................................... 7-5

8. SUMMARY AND OUTCOME ....................................................................... 8-1

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

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

9. REFERENCES ................................................................................................ 9-1

LIST OF APPENDICES

Appendix A. Data Usability Assessment and Validation Reports

Appendix B. Field Documentation

B1. Log of Daily Notice of Field Activities

B2. Sampling Forms

B3. Survey Data

B4. Field Change Request Form

B5. Investigation-Derived Waste Locations

Appendix C. Photographic Log

Appendix D. Technical Project Planning Meeting Minutes

Appendix E. Boring Logs and Well Construction Diagrams

Appendix F. Analytical Results

Appendix G. Laboratory Reports
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LIST OF FIGURES

Figure 2-1 Facility Location

Figure 2-2 Facility Topography

Figure 2-3 Groundwater Features

Figure 2-4 Surface Water Features

Figure 2-5 Groundwater Elevations, November 2021

Figure 3-1 Areas of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOA Detections in Soil

Figure 6-2 PFOS Detections in Soil

Figure 6-3 PFBS Detections in Soil

Figure 6-4 PFHxS Detections in Soil

Figure 6-5 PFNA Detections in Soil

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

Figure 6-7 PFHxS and PFNA Detections in Groundwater

Figure 7-1 Conceptual Site Model, AOI 1

Figure 7-2 Conceptual Site Model, AOI 2

Figure 7-3 Conceptual Site Model, AOI 3
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LIST OF TABLES

Table ES-1 Screening Levels (Soil and Groundwater)

Table ES-2 Summary of Site Inspection Findings and Recommendations

Table 5-1 Samples by Medium, Bismarck AASF #1, North Dakota, Site Inspection Report

Table 5-2 Soil Boring Depths and Temporary Well Screen Intervals, Bismarck AASF #1,

North Dakota, Site Inspection Report

Table 5-3 Groundwater Elevation, Bismarck AASF #1, North Dakota, Site Inspection

Report

Table 6-1 Screening Levels (Soil and Groundwater)

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

Report, Bismarck AASF #1

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

Site Inspection Report, Bismarck AASF #1

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

Inspection Report, Bismarck AASF #1

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

Report, Bismarck AASF #1

Table 8-1 Summary of Site Inspection Findings and Recommendations
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LIST OF ACRONYMS AND ABBREVIATIONS

°C Degrees Celsius

°F Degrees Fahrenheit

% Percent

μg/kg Microgram(s) per kilogram

AASF Army Aviation Support Facility

AECOM AECOM Technical Services, Inc.

AFFF Aqueous Film Forming Foam

AOI Area of Interest

ARNG Army National Guard

bgs Below ground surface

btoc Below top of casing

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

COC Chain-of-custody

CSM Conceptual site model

DA Department of the Army

DoD Department of Defense

DPT Direct-push technology

DQI Data quality indicator

DQO Data quality objective

DUA Data Usability Assessment

EA EA Engineering, Science, and Technology, Inc., PBC

EDR Environmental Data Resources, Inc.

EIS Extraction internal standards

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

EB Equipment Blank

FB Field blank

FedEx Federal Express

ft Foot (feet)

GIS Geographic information systems

GPR Ground-penetrating radar

HEF High Expansion Foam

HDPE High-density polyethylene

HFPO-DA Hexafluoropropylene oxide dimer acid

HQ Hazard Quotient
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IDW Investigation-derived waste

ITRC Interstate Technology Regulatory Council

LC/MS/MS Liquid chromatography tandem mass spectrometry

LCS Laboratory control sample

LCSD Laboratory control sample duplicate

LOQ Limit of quantification

MIL-SPEC military specification

MS Matrix spike

MSD Matrix spike duplicate

msl Mean sea level

ND North Dakota

NDDEQ North Dakota Department of Environmental Quality

NELAP National Environmental Laboratory Accreditation Program

ng/L Nanogram(s) per liter

No. Number

OSD Office of the Secretary of Defense

PA Preliminary assessment

PFAS Per- and polyfluoroalkyl substances

PFBS Perfluorobutanesulfonic acid

PFHxS Perfluorohexanesulfonic acid

PFNA Perfluorononanoic acid

PFOA Perfluorooctanoic acid

PFOS Perfluorooctanesulfonic acid

PID Photoionization detector

PQAPP Programmatic UFP-QAPP

PVC Polyvinyl chloride

QA Quality assurance

QAPP Quality Assurance Project Plan

QC Quality control

QSM Quality Systems Manual

RI Remedial investigation

RPD Relative percent difference

SI Site Inspection

SL Screening level

TOC Total organic carbon

TPP Technical Project Planning
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UFP Uniform Federal Policy

USACE U.S. Army Corps of Engineers

USEPA U.S. Environmental Protection Agency

Wood Wood Environment & Infrastructure Solutions, Inc.

WSP WSP USA Environment and Infrastructure, Inc.
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EXECUTIVE SUMMARY

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

Inspections (SIs) at ARNG facilities nationwide based on the current or potential historical use of

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

memorandum regarding Investigating Per- and Polyfluoroalkyl Substances within the

Department of Defense Cleanup Program (Assistant Secretary of Defense, 2022) from the Office

of the Secretary of Defense (OSD) dated 6 July 2022. The six compounds listed in the OSD

memorandum include perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA),

perfluorobutanesulfonic acid (PFBS), perfluorononanoic acid (PFNA), perfluorohexanesulfonic

acid (PFHxS), and hexafluoropropylene oxide dimer acid (HFPO-DA)1. These compounds are

collectively referred to as “relevant compounds” throughout the document, and the applicable

screening levels (SLs) are provided below in Table ES-1.

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

used, stored, disposed, or released historically (see Table ES-2 for AOI locations). The objective

of the SI is to identify whether there has been a release to the environment from the AOIs

identified in the PA and determine whether further investigation is warranted, a removal action is

required to address immediate threats, or no further action is required based on SLs for the

relevant compounds. This SI was completed at the Bismarck Army Aviation Support Facility

(AASF) #1 in Bismarck, North Dakota and determined that further investigation is warranted for

AOI 1: Main Hangar, AOI 2: Fuel Point, AOI 3: Fuel Truck Parking, and potential upgradient

PFAS sources. The Bismarck AASF #1 will also be referred to as the “Facility” throughout this

document.

The Facility, operated by North Dakota ARNG (NDARNG), encompasses approximately 33.65

acres in Bismarck, North Dakota. The Facility is in Burleigh County, approximately 3 miles

south of Bismarck, North Dakota. The Facility is located on the Bismarck Municipal Airport.

The Facility is constructed on a parcel of land that has been leased and operated by the

NDARNG since 1996. The term of the lease began in 1996 with a 50-year duration (AECOM,

2020).

The PA identified one AOI for investigation during the SI phase, AOI 1: Main Hangar. SI

sampling results from AOI 1 were compared to OSD SLs. After the SI fieldwork was completed,

two additional potential PFAS release areas were identified: AOI 2: Fuel Point and AOI 3: Fuel

Truck Parking. Table ES-2 summarizes the SI results for the AOIs. Based on the results of this

SI, further evaluation under CERCLA is warranted in a Remedial Investigation (RI) for AOI 1:

Main Hangar. As the identification of AOI 2 and AOI 3 did not occur until after the SI fieldwork,

1 Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to

as GenX) was not included as an analyte at the time of this SI. Based on the conceptual site model (CSM) developed

during the PA and revised based on SI findings, the presence of HFPO-DA is not anticipated at the facility because

HFPO-DA is generally not a component of military specification (MIL-SPEC) aqueous film forming foam (AFFF)

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

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

in the absence of other PFAS.
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investigation of these AOIs was not completed during the SI. AOI 2: Fuel Point, and AOI 3:

Fuel Truck Parking will be assessed during the RI.

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

Analyte2

Residential

(Soil)

(μg/kg)1

(0-2 feet bgs)

Industrial / Commercial

Composite Worker

(Soil)

(μg/kg)1

(2-15 feet bgs)

Tap Water

(Groundwater)

(ng/L)1

PFOA 19 250 6

PFOS 13 160 4

PFBS 1,900 25,000 601

PFHxS 130 1,600 39

PFNA 19 250 6

Notes:

1. Assistant Secretary of Defense. July 2022. Risk Based Screening Levels in Groundwater and

Soil using United States Environmental Protection Agency’s (USEPA’s) Regional

Screening Level Calculator. Hazard Quotient (HQ)=0.1. May 2022.

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

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

on the CSM developed during the PA and revised based on SI findings, the presence of

HFPO-DA is not anticipated at the facility because HFPO-DA is generally not a component

of MIL-SPEC AFFF and based on its history including distribution limitations that

restricted use of GenX, it is generally not a component of other products the military used.

In addition, it is unlikely that GenX would be an individual chemical of concern in the

absence of other PFAS.

Abbreviations:

μg/kg = microgram(s) per kilogram

ng/L = nanogram(s) per liter

bgs = below ground surface

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

AOI

Potential Release

Area

Soil –

Source Area

Groundwater –

Source Area

Groundwater –

Facility Boundary Future Action

1 Main Hanger Proceed to RI

2 Fuel Point TBD TBD TBD Proceed to RI

3 Fuel Truck Parking TBD TBD TBD Proceed to RI

Legend:

 = Detected; exceedance of screening levels

 = Detected; no exceedance of screening levels

 = Not detected
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1. INTRODUCTION

1.1 PROJECT AUTHORIZATION

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

Assessments (Pas) and Site Inspections (SIs) at ARNG facilities nationwide based on the current

or potential historical use of per- and polyfluoroalkyl substances (PFAS) with a focus on the six

compounds presented in the memorandum regarding Investigating Per- and Polyfluoroalkyl

Substances within the Department of Defense Cleanup Program (Assistant Secretary of Defense,

2022) from the Office of the Secretary of Defense (OSD) dated 6 July 2022. The six compounds

listed in the OSD memorandum are referred to as “relevant compounds” throughout this

document and include perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA),

perfluorobutanesulfonic acid (PFBS), perfluorononanoic acid (PFNA), perfluorohexanesulfonic

acid (PFHxS), and hexafluoropropylene oxide dimer acid (HFPO-DA)1. The ARNG performed

this SI at the Bismarck Army Aviation Support Facility (AASF) #1 in Bismarck, North Dakota.

The Bismarck AASF #1 is also referred to as the “Facility” throughout this report.

The SI project elements were performed in accordance with the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA) (U.S. Environmental

Protection Agency [EPA], 1980), as amended, the National Oil and Hazardous Substances

Pollution Contingency Plan (40 Code of Federal Regulations Part 300; EPA, 1994), and in

compliance with U.S. Department of Army (DA) requirements and guidance for field

investigations.

1.2 SITE INSPECTION PURPOSE

A PA was performed at the Facility (AECOM Technical Services, Inc. [AECOM], 2020) that

identified one Area of Interest (AOI) where PFAS-containing materials may have been used,

stored, disposed, or released historically. The objective of the SI is to identify whether there has

been a release to the environment from the AOI identified in the PA and determine whether

further investigation is warranted, a removal action is required to address immediate threats, or

no further action is required based on screening levels (SLs) for the relevant compounds.

1

 Of the six PFAS compounds presented in the 6 July 2022 OSD memorandum, HFPO-DA (commonly referred to as

GenX) was not included as an analyte at the time of this SI. Based on the conceptual site model (CSM) developed

during the PA and revised based on SI findings, the presence of HFPO-DA is not anticipated at the facility because

HFPO-DA is generally not a component of military specification (MIL-SPEC) aqueous film forming foam (AFFF)

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

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

in the absence of other PFAS.
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2. FACILITY BACKGROUND

2.1 FACILITY LOCATION AND DESCRIPTION

The Facility is in Burleigh County, approximately three miles south of Bismarck, North Dakota

and located on the Bismarck Municipal Airport property (Figure 2-1). The Facility is accessible

from Yegen Road from the south off of Airway Avenue. The Facility is constructed on a parcel

of land that has been leased and operated by the North Dakota Army National Guard

(NDARNG) since 1996. The Facility comprises approximately 33.65 acres of land owned by the

City of Bismarck. The term of the lease began in 1996 with a 50-year duration (AECOM, 2020).

2.2 FACILITY ENVIRONMENTAL SETTING

The Bismarck AASF #1 is completely surrounded by the Bismarck Municipal Airport property.

The areas beyond the airport property are mostly agricultural areas to the west, south, and east;

light industrial areas directly south and to the north; a heavy industrial area to the northeast; and

residential areas to the west (approximately 0.5 mile) and to the southwest (approximately 1.1

miles). The Facility sits at an elevation of approximately 1,650 feet (ft) above mean sea level

(msl) and is located approximately 2.5 miles east of the Missouri River.

The following sections include information on geology, hydrogeology, hydrology, climate, and

current and future land use. The topography at the Facility is shown on Figure 2-2. The regional

geology and groundwater features are shown on Figure 2-3. The regional surface water features

and drainage basins are shown on Figure 2-4. Groundwater elevations and contours are

presented on Figure 2-5.

2.2.1 Geology

The Facility is located within the Apple Creek Uplands subdistrict of the Coteau Slope

physiographic region. The Apple Creek Uplands subdistrict is known for having steep dissected

valley walls and uplands. These valley walls and uplands have a thin sheet of drift over the

bedrock. The glacial drift in the area is almost non-existent and typically just contains boulders

and scattered patches of till, from the Wisconsin glaciation. In the Lake McKenzie Basin,

alluvial sand and gravel primarily cover the floodplain deposits. Lake McKenzie Basin also

contains moraine landforms that were created from the buildup of drift and till deposition from

glacial ice. The sheet moraine that is located in the Apple Creek Uplands subdistrict has a thin

layer of drift composed of till that lies over the stream-eroded bedrock. The layer of drift

comprises outwash plain, end moraine, dead-ice moraine, ground moraine, and sheet moraine

(AECOM, 2020).

During the SI, seven borings were advanced between 11.5 to 15 ft below ground surface (bgs).

The soil was classified as poorly graded sand overlying clay (at approximately 10 to 11 ft bgs) at

all boring locations. The grain size analysis conducted on the soil sample collected from the

AOI confirms the field observation of poorly graded sand.
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2.2.2 Hydrogeology

As part of the PA, a search of available environmental records was conducted by Environmental

Data Resources, Inc. (EDRTM), which included a well search within a one-mile radius

surrounding the Facility. Additionally, online resources, such as state and local Geographic

Information Systems (GIS) databases were used to expand the well search to a four-mile radius

around the Facility. No potable water wells are located within the boundary of the AASF. Two

domestic, seven irrigation, 13 monitoring, and four wells of unknown use are located within a

two-mile radius of the Facility (AECOM, 2020). The regional groundwater flow direction

within the surficial aquifer was inferred to be easterly based on the location of surficial water

bodies, namely Apple Creek located east of the facility. From a review of the North Dakota

Department of Water Resources MapServices there are four wells (one domestic well, two

irrigation wells, and an unknown well) that are within approximately one mile of the facility and

potentially downgradient (Figure 2-3). According to the North Dakota Department of Water

Resources MapServices, the domestic well is screened from 0 to 163 ft bgs, one irrigation well is

screened from 77 to 87 ft bgs, the second irrigation well is screened from 0 to 81 ft bgs, and the

unknown well is screened from 0 to 87 ft bgs (North Dakota, 2022). All other wells located

within a two-mile radius of the Facility are located upgradient and cross-gradient of the Facility.

Depths to groundwater at the Facility as measured in November 2021 during the SI ranged from

8.5 to 11 ft bgs. Synoptic water level measurements taken from temporary wells during the SI

fieldwork (see Section 5.4) indicated that the local groundwater flow is northeasterly.

Groundwater elevation contours from the SI are presented on Figure 2-4. Drinking water for the

Facility is supplied by the City of Bismarck Public Works, which sources water from the

Missouri River (AECOM, 2020).

The Apple Creek Uplands subdistrict, which encompasses the Facility, is known for its streameroded bedrock and is covered with sheet moraine. In the drainage basin of Apple Creek, there

are notable areas of sand dunes. This drainage valley carries some outwash but typically carries

meltwater. The meltwater channels flow on high bedrock drainage divides and combines with

other meltwater locations into the Missouri River. The valley fill ranges from depths of 4 to 20 ft

(North Dakota Geological Survey, 1965; AECOM, 2020).

2.2.3 Hydrology

The Facility is located just to the east of the Missouri River, within the drainage basin of Apple

Creek, which is part of the Missouri River Basin. Apple Creek is located approximately 0.5 miles

to the east of the Facility, which flows to the south and discharges to the Missouri River. The

Facility is connected to the Bismarck City Sewer System which leads to the Bismarck City

wastewater treatment plant. At the Facility, surface runoff flows toward the catch basins located

throughout the Facility (Figure 2-4). Surface runoff at the Facility exits to the northeast and

enters the shared airport stormwater system and then ultimately discharges into Apple Creek

located east of the Facility (AECOM, 2020).
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2.2.4 Climate

The climate at the AASF consists of warm summers, freezing dry windy winters, and is partly

cloudy year-round. The average temperature is 42.8 degrees Fahrenheit (°F), with warmer

temperatures to at least 84°F and colder temperatures to at least -1.6°F. The annual average

precipitation is 17.82 inches (AECOM, 2020).

2.2.5 Current and Future Land Use

The AASF is located on the Bismarck Municipal Airport. The Facility consists of an

administration building, office areas, and hangars. Exterior features are vehicle parking areas and

roads. Infrastructure improvements, land acquisitions, land use controls, and reasonably

anticipated future land use is not anticipated to change (AECOM, 2020). The facility is fenced

and has restricted access areas.

2.2.6 Sensitive Habitat and Threatened/Endangered Species

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

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

in the surrounding area.

The following species are listed as federally endangered, threatened, proposed, and/or candidate

species in Burleigh County, North Dakota (U.S. Fish and Wildlife Services, 2021):

Birds: Whooping Crane, Grus americana (endangered); Piping Plover, Charadrius melodus

(threatened); Red Knot, Calidris canutus rufa (threatened)

Insects: Dakota Skipper, Hesperia dacotae (threatened); Monarch Butterfly, Danaus plexippus

(candidate)

Mammals: Northern Long-eared Bat, Myotis septentrionalis (threatened).

2.3 HISTORY OF PFAS USE

Aqueous film forming foam (AFFF), a firefighting agent, was commonly used by the U.S.

military to extinguish petroleum fires, for firefighting training, and for the suppression of fires in

uncontained areas. Military use of AFFF began in the 1970s and was most widely used at

Department of Defense (DoD) installations with airfields. The Main Hangar was identified as a

potential PFAS release area at the Facility during the PA (AECOM, 2020). A fire suppression

system for the Main Hangar was installed in 2006 by the NDARNG during the construction of

the northern section of the Main Hangar. The Main Hangar fire suppression system consists of

one 300-gallon tank filled with two percent (%) C2 High Expansion Foam (HEF), although it is

unknown whether two percent C2 HEF contains fluorinated compounds. Approximately 100

gallons of bulk 6% AFFF, for use during overland firefighting response, was stored in the

Hazardous Materials Room which is located in the northern section of the Main Hangar. There

were also 14 TriMax30TM fire extinguishers filled with AFFF stored inside the Main Hangar,

some of which were taken out on the ramp for very short durations for operations. While there
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were no known releases noted in the PA, the Main Hangar was identified as an AOI due to the

storage of PFAS at the Facility. During preparation of the SI Report, it was discovered that

TriMax30TM fire extinguishers had occasionally been stored at the Fuel Point and the Fuel Truck

Parking since at least 2011. Based on this information, the Fuel Point and the Fuel Truck Parking

were identified as AOIs and will also be investigated as part of the RI. A description of each AOI

is presented in Section 3.
Army National Guard Site Inspections

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Bismarck AASF #1, North Dakota

Figure 2-1

Facility Location

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China

(Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User

Community

3

ND

^_

Data Sources: 

ESRI 2020

AECOM 2020

Date:.......................JANUARY 2022

Prepared By:.........................WOOD

Prepared For:........................USACE

Projection:......NAD 1983 StatePlane

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Facility Data

Facility Boundary

Bismarck AASF #1

0 5,000 10,000 20,000

Feet
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Figure 2-2

Facility Topography

Hazardous

Material Room

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Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,

and the GIS User Community

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Data Sources: 

ESRI 2020

AECOM 2020

Date:.............................APRIL 2022

Prepared By:.........................WOOD

Prepared For:........................USACE

Projection:......NAD 1983 StatePlane

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Facility Data

Building

Potential PFAS Release

Area of Interest

Facility Boundary

Topography

Elevation Contour (10 ft.

interval, NAVD88 datum)

0 700 1,400 2,800

Feet
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Figure 2-3

Groundwater Features

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Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,

and the GIS User Community

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Data Sources: 

ESRI 2020

AECOM 2020

Date:....................JANUARY 2022

Prepared By:.......................WOOD

Prepared For:......................USACE

Projection:....NAD 1983 StatePlane

G:\ANG\a_MXD\BismarkND\Figure 10-2 Groundwater Features.mxd - megan.cameron - 1/21/2022 - 10:38:42 AM

0 1,200 2,400 600

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Facility Data

Facility Boundary

Wells

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A@ Monitoring/Observation Well

A! Other/Unknown Well

Hydrology/Hydrogeology

Shallow Groundwater Flow

Direction (November 2021)

Rivers/Streams

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Apple Creek
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Figure 2-4

Surface Water Features

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Hazardous

Material Room

Maintenance Room

Culvert Ultimately 

Discharges into Apple Creek

AOI 1:

Main

Hanger

C12 Hanger
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Figure 2-5

Groundwater Elevations, November 2021

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Discharges into Apple Creek

1642

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3. SUMMARY OF AREAS OF INTEREST

The PA evaluated areas where PFAS-containing materials may have been used, stored, disposed,

or released historically. Based on the PA findings, one potential release area was identified at the

Facility and identified as: AOI 1 Main Hanger. AOI 1 is the subject of this SI. During

preparation of the SI Report, two additional potential release areas were identified and will be

assessed during the RI: AOI 2 Fuel Point and AOI 3 Fuel Truck Parking. The AOIs are shown on

Figure 3-1.

3.1 AOI 1 – MAIN HANGAR

The Main Hangar AOI is located in the northwestern portion of the Bismarck AASF #1 property

and consists of two hangar spaces (northern and southern) connected by a smaller room used for

the storage of maintenance equipment (Maintenance Room). The southern hangar was built in

1975 without a fire suppression system, and the northern hangar was built in 2006. A fire

suppression system for the entire Main Hangar was installed in 2006 by the NDARNG during

the construction of the northern hangar. The hangar fire suppression system consists of one 300-

gallon tank filled with 2% C2 HEF. Following installation in 2006, the fire suppression system

was tested resulting in a full system release to the hangar. The hangar doors were closed during

testing allowing the C2 HEF to flow to the Main Hangar drains, which drain to the oil/water

separator (OWS) (AECOM, 2020). It is unknown whether 2% C2 HEF contains fluorinated

compounds; however, due to the uncertainty of the unknown chemical composition of the 2% C2

HEF, the area immediately surrounding the Main Hangar was included in the boundary of AOI

1. The structural integrity of the OWS and the sewer lines is unknown and can potentially act as

a conduit for PFAS migration to the groundwater.

Fourteen TriMax30TM fire extinguishers filled with AFFF were observed in the Main Hangar

during the PA facility visit. Some of these fire extinguishers were taken out on the ramp for very

short durations for operations. Disposal records document the disposal of 10 TriMax30TM fire

extinguishers. A thorough search has been conducted at the facility, and no TriMax30TM fire

extinguishers remain. The four TriMax30TM fire extinguishers that remain unaccounted for may

have been shipped elsewhere between the PA Facility visit and the disposal of the 10

TriMax30TM fire extinguishers.

Historically, hydrostatic testing was conducted on the TriMax30TM fire extinguishers every five

years. During the testing, NDARNG emptied the TriMax30TM fire extinguishers into

polyethylene tanks that were stored in the Maintenance Room. The emptied TriMax30TM fire

extinguishers were sent to a contractor to undergo hydrostatic testing. When the fire

extinguishers were returned, they were refilled by the NDARNG with the original AFFF solution

from the polyethylene tanks in the Maintenance Room. All the drains in the Maintenance Room

discharge into an OWS. According to the PA, the TriMax30TM fire extinguishers have not been

used to put out a fire, or in fire training exercises (AECOM, 2020). All AFFF liquids, debris, and

equipment have been removed from the Facility and are no longer present.

Approximately 100 gallons of bulk 6% AFFF, for use during overland firefighting response, was

also historically stored in the Hazardous Materials Room, located in the northern section of the

Main Hangar. Potential releases identified at the Facility may have occurred on paved surfaces.
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AFFF releases to the paved surfaces could have infiltrated the subsurface via cracks in the

pavement or joints between areas that are paved. If the 2006 release of 2% C2 HEF was not

contained within the Main Hangar, 2% C2 HEF runoff could have traveled to the unpaved

surface and infiltrated the soil into the groundwater, or to the stormwater catch basins located at

the ramp area. The stormwater lines ultimately discharge to Apple Creek (AECOM, 2020).

3.2 AOI 2 – FUEL POINT

Following the SI fieldwork, photographs were found showing that a TriMax30TM fire

extinguisher was stored near the Fuel Point for emergencies. The photographs of the

TriMax30TM were taken in 2011. Subsequent photographs of the area indicate that the fire

extinguisher was replaced sometime between 2011 and 2020.

3.3 AOI 3 – FUEL TRUCK PARKING

Following the SI fieldwork, photographs were found showing that a TriMax30TM fire

extinguisher was stored near the Fuel Truck Parking for emergencies. The photographs of the

TriMax30TM were taken in 2017. Subsequent photographs of the area indicate that the fire

extinguisher was replaced sometime between 2017 and 2020.

3.4 ADJACENT SOURCES

Two potential off-facility sources of PFAS are adjacent to the Facility and are not under the

control of the NDARNG. A description of each off-facility source is presented below and shown

on Figure 3-1.

3.4.1 Bismarck Airport Fire Department

The Bismarck Airport Fire Department provides emergency response to the Facility. The fire

department is located approximately 0.75 miles northwest of the Facility on the Bismarck

Airport property. Based on synoptic water levels measured during the SI (see Section 5.4), the

Bismarck Airport Fire Department appears to be cross-gradient of the Facility (Figure 3-1). The

Bismarck Airport Fire Department has three fire trucks with AFFF tanks. One truck has a 400-

gallon capacity of AFFF, and the other two have a 200-gallon capacity of AFFF. The fire

department has approximately 800 to 1,000-gallons of bulk 6% AFFF stored within the fire

station. The fire department has never had to respond to a fire or crash at the airport. During

annual fire truck nozzle testing, the AFFF is dispensed from the fire trucks and containerized in

55-gallon drums. It is unknown whether the nozzle testing has always been performed in a

manner that containerizes AFFF. Annual fire training by the fire department is currently

conducted using only water, but it is unknown whether AFFF has ever been used for training

purposes (AECOM, 2020).

3.4.2 Corporate Hangars

Private corporate hangars are located approximately 0.88 miles northwest of the Facility. Based

on synoptic water levels measured during the SI (see Section 5.4), the Corporate Hangars

appears to be cross-gradient of the Facility (Figure 3-1). There are also numerous hangar
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facilities located northwest of the Main Terminal. An interviewee with the NDARNG stated that

the corporate hangars have a fire suppression system; however, the type of fire suppressant used

in the fire suppression system is unknown. The corporate hangars have been identified as a

potential adjacent source due to the possibility that the fire suppression system may contain

AFFF. No additional information for the corporate hangar was available during the Facility visit

(AECOM, 2020).
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Figure 3-1

Areas of Interest

AOI 1: Main

Bismarck

Airport FD

Corporate

Hangar

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4. PROJECT DATA QUALITY OBJECTIVES

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

Federal Policy (UFP)-Quality Assurance Project Plan (QAPP) Addendum (EA/Wood, 2021a),

the objective of the SI is to identify whether there has been a release to the environment at the

AOIs identified in the PA. For each AOI, ARNG determines if further investigation is warranted,

a removal action is required to address immediate threats, or whether no further action is

warranted. This SI evaluated groundwater and soil for the presence or absence of relevant

compounds at AOI 1; AOIs 2 and 3 will be assessed during the RI.

4.1 PROBLEM STATEMENT

ARNG will recommend an AOI for remedial investigation (RI) if related soil and groundwater

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

are presented in Section 6.1 of this Report.

4.2 INFORMATION INPUTS

Primary information inputs for the SI include the following:

 The PA Report for Bismarck AASF #1 (AECOM, 2020);

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

accordance with the facility-specific UFP –QAPP Addendum (EA/Wood, 2021a); and

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

parameters measured at the time of sampling.

4.3 STUDY BOUNDARIES

The scope of the SI was bounded horizontally by the property limits of the Facility (Figures 2-1

and 2-2). Off-facility sampling was not included in the scope of this SI. If future off-facility

sampling is required, the proper stakeholders will be notified, and necessary rights of entry will

be obtained by ARNG with property owner(s). The scope of the SI was vertically bounded as

follows: groundwater (11 ft bgs) and soil from direct-push technology (DPT) borings (15 ft bgs).

Temporal boundaries were limited to the earliest available time field resources were available to

complete the study.

4.4 ANALYTICAL APPROACH

Samples were analyzed by Eurofins, accredited under the DoD Environmental Laboratory

Accreditation Program (DoD ELAP; Accreditation Number 1.01) and the National

Environmental Laboratory Accreditation Program (NELAP; Certificate Number 021). Data were

compared to applicable SLs within this document and decision rules as defined in the UFPQAPP Addendum (EA/Wood, 2021a).
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4.5 DATA USABILITY ASSESSMENT

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

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

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

and qualitative methods, the assessment determines whether project execution and the resulting

data have met installation specific DQOs. Both sampling and analytical activities are considered

to assess whether the collected data are of the right type, quality, and quantity to support the

decision-making (DoD, 2019a, DoD, 2019b, USEPA, 2017).

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

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

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

requirements of the UFP-QAPP (EA, 2020a).
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5. SITE INSPECTION ACTIVITIES

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

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

implemented in accordance with the following approved documents.

 Final Preliminary Assessment Report, Bismarck Army Aviation Support Facility

#1, North Dakota, dated August 2020 (AECOM, 2020)

 Final Programmatic Uniform Federal Policy-Quality Assurance Project Plan,

Site Inspections for Per- and Polyfluoroalkyl Substances Impacted Sites, ARNG

Installations, Nationwide, dated December 2020 (EA, 2020a)

 Final Site Inspection Uniform Federal Policy-Quality Assurance Project Plan

Addendum, Bismarck Army Aviation Support #1, North Dakota dated October

2021 (EA/Wood, 2021a)

 Final Programmatic Accident Prevention Plan, Revision 1, dated November 2020

(EA, 2020b)

 Final Site Safety and Health Plan, Bismarck Army Aviation Support Facility #1,

North Dakota, dated May 2021 (EA/Wood, 2021b).

The SI field activities were conducted from 01 to 03 November 2021 and consisted of

utility clearance, DPT borings and soil sample collection, temporary monitoring well

installation and grab groundwater sample collection, and land surveying. Field activities

were conducted in accordance with the UFP-QAPP Addendum (EA/Wood, 2021a),

except as noted in Section 5.8.

The following samples were collected during the SI and analyzed for 24 compounds via

liquid chromatography/tandem mass spectrometry (LC/MS/MS) compliant with QSM

Version 5.3 Table B-15 to fulfill the project DQOs:

 Nine (9) soil samples from three locations (AOI01-02, AOI01-03, and AOI01-

04);

 Seven (7) grab groundwater samples from temporary well locations;

 Five (5) quality assurance (QA)/quality control (QC) samples.

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

presents the list of samples collected for each medium. Field documentation is provided

in Appendix B. A log of Daily Notice of Field Activity was completed throughout the SI

field activities, which is provided in Appendix B1. Sampling forms are provided in

Appendix B2, land survey data are provided in Appendix B3, a Field Change Request

Form is provided in Appendix B4, and investigation-derived waste (IDW) placement

locations are provided in Appendix B5. Additionally, a photographic log of field

activities is provided in Appendix C.
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5.1 PRE-INVESTIGATION ACTIVITIES

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

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

water. Additionally, a Facility visit with Wood Environment & Infrastructure Solutions, Inc.

(Wood, prior to 21 September 2022, now WSP USA Environment and Infrastructure, Inc.

[WSP]), ARNG, NDARNG, and North Dakota Department of Environmental Quality (NDDEQ)

was conducted. Details of these activities are presented below.

5.1.1 Technical Project Planning

The U.S. Army Corps of Engineers (USACE) TPP Process, Engineers Manual (EM) 200-1-2

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

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

collection plan. The process encourages stakeholder involvement in the SI, beginning with

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

address the AOIs identified in the PA.

A combined TPP Meeting 1 and 2 was held on 05 October 2021, prior to SI field activities. The

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

of TPP Meeting 1 and 2, Wood, ARNG, NDARNG, and NDDEQ conducted a Facility walk.

The stakeholders for this SI include ARNG, NDARNG, NDDEQ, USACE, and representatives

familiar with the Facility, the regulations, and the community. Stakeholders were provided the

opportunity to make comments on the technical sampling approach and methods at the combined

TPP Meeting 1 and 2. The outcome of the combined TPP Meeting 1 and 2 was memorialized in

the UFP-QAPP Addendum (EA/Wood 2021a).

A TPP Meeting 3 was held after the field event to discuss the results of the SI. Meeting minutes

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

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

5.1.2 Utility Clearance

WSP contacted the North Dakota One Call to notify them of intrusive work at the Facility. Wood

contracted GPRS, Inc., a private utility location service, to perform utility clearance at the

Facility. Utility clearance was performed at each of the proposed boring locations on 01

November 2021 with input from the WSP field team. General locating services and groundpenetrating radar (GPR) were used to complete the clearance. Additionally, the first 5 feet of

each boring were pre-cleared by WSP’s drilling subcontractor, Dakota Drilling, Inc., using a

hand auger to verify utility clearance in shallow subsurface where utilities would typically be

encountered.
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5.1.3 Source Water and PFAS Sampling Equipment Acceptability

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

acceptability criteria, as defined in the UFP-QAPP Addendum, prior to the start of field

activities. A sample from a potable water source at Bismarck AASF #1, was collected on 05

October 2021, prior to mobilization, and analyzed for PFAS by LC/MS/MS compliant with QSM

5.3 Table B-15 (DoD, 2020). The results of the sample of the potable water source used for

decontamination of drilling and reusable sampling equipment during the SI are provided in

Appendix F. A discussion of the results is presented in the Data Usability Assessment

(Appendix A).

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

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

environment was provided in the Standard Operating Procedures appendix to the Programmatic

UFP-QAPP (PQAPP) (EA, 2020a).

5.2 SOIL BORINGS AND SOIL SAMPLING

Soil samples were collected via DPT drilling methods in accordance with Standard Operating

Procedure 047 Direct-Push Technology Sampling (EA, 2021a). A Geoprobe® 7822DT dual-tube

sampling system was used to collect continuous soil cores to the target depth. A hand auger was

used to collect soil from the top 5 ft of the boring in compliance with utility clearance

procedures. The soil boring locations are shown on Figure 5-1, and boring sample depths are

provided in Table 5-1. Several boring locations were adjusted within an 80-feet offset for

reasons including drill rig access, utility avoidance and bias toward sampling within observed

drainage features.

Three discrete soil samples were collected for chemical analysis from each of three soil borings:

one sample at the surface (0 to 2 ft bgs) and two subsurface soil samples. One subsurface soil

sample was collected approximately 1 ft above the groundwater table and one collected at the

mid-point between the surface and the groundwater table (not to exceed 15 ft bgs). Groundwater

was encountered at depths ranging from 8.39 to 10.92 ft bgs during drilling. Total boring

completion depths, to accommodate temporary well installation, ranged from 12 to 15 ft bgs.

During the drilling, the soil cores were continuously logged for lithological descriptions by a

field geologist using the Unified Soil Classification System. A photoionization detector (PID)

was used to screen the breathing zone during boring activities as a part of personal safety

requirements. Observations and measurements were recorded on sampling forms (Appendix B2)

and in a non-treated field logbook. Depth interval, recovery thickness, PID concentrations,

moisture, relative density, Munsell color, and Unified Soil Classification System texture were

recorded. The boring logs are provided in Appendix E.

Each sample was collected into a laboratory-supplied PFAS-free high-density polyethylene

(HDPE) bottle and labeled using a PFAS-free marker or pen. Samples were packaged on ice and

transported via Federal Express (FedEx) under standard chain-of-custody (COC) procedures to

the laboratory and analyzed for PFAS (liquid chromatography tandem mass spectrometry

[LC/MS/MS] compliant with QSM Version 5.3 Table B-15), total organic carbon (TOC, EPA
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Method 9060A), pH (EPA Method 9045D), and grain size (ASTM Method D-422) in accordance

with the UFP-QAPP Addendum (EA/Wood, 2021a).

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

the accompanying samples. Matrix spike/matrix spike duplicate (MS/MSD) were collected at a

rate of 5% and analyzed for the same parameters as the accompanying samples. In instances

when non-dedicated sampling equipment was used, such as a hand auger for the shallow soil

samples, one equipment blank (EB) was collected per day and analyzed for the same parameters

as the soil samples. A temperature blank was placed in each cooler for use in confirming that

samples were preserved at or below 6 degrees Celsius (°C) during shipment.

DPT borings were converted to temporary wells, which were subsequently abandoned after

sampling and surveying in accordance with the UFP-QAPP Addendum (EA/Wood, 2021a).

After removal of the casings, boreholes were abandoned using bentonite chips. Borings were

installed in grass areas to avoid disturbing concrete or asphalt surfaces.

5.3 TEMPORARY WELL INSTALLATION AND GROUNDWATER GRAB

SAMPLING

Temporary wells were installed using a GeoProbe®7822DT dual-tube sampling system. Once

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

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

the ground surface. New PVC pipe and screen were used at each location to avoid cross

contamination between locations. The screen intervals for the temporary wells are provided in

Table 5-2.

Groundwater samples were collected after a period of time following well installation to allow

groundwater to infiltrate and recharge the temporary well screen intervals. After the recharge

period, groundwater samples were collected using a peristaltic pump with PFAS-free HDPE

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

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

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

meter and recorded on the field sampling form (Appendix B2) before each grab sample was

collected in a separate container. The temporary monitoring wells at locations AOI01-03 and

AOI01-04 went dry while purging, therefore the groundwater samples were collected after the

wells recharged enough to fill the sample containers in accordance with the UFP-QAPP

Addendum (EA/Wood, 2021a). Additionally, a subsample of each groundwater sample was

collected in a separate container, and a shaker test was completed to identify if there were any

foaming. No foaming was noted in any of the groundwater samples.

Each sample was collected in laboratory-supplied PFAS-free HDPE bottles and labeled using a

PFAS-free marker or pen. Samples were packaged on ice and transported via FedEx under

standard COC procedures to the laboratory and analyzed for PFAS by LC/MS/MS compliant

with QSM Version 5.3 Table B-15 in accordance with the UFP-QAPP Addendum (EA/Wood,

2021a).
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Field duplicate samples were collected at a rate of 10% and analyzed for the same parameters as

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

parameters as the accompanying samples. One field blank (FB) sample was collected in

accordance with the UFP-QAPP Addendum (EA, 2021a). A temperature blank was placed in

each cooler for use in confirming that samples were preserved at or below 6°C during shipment.

Following well surveying (described below in Section 5.7), temporary wells were abandoned in

accordance with the SI UFP-QAPP Addendum (EA/Wood, 2021a) by removing the PVC and

backfilling the hole with bentonite chips.

5.4 SYNOPTIC WATER LEVEL MEASUREMENTS

A synoptic groundwater gauging event was performed on 3 November 2021. Groundwater

elevation measurements were collected from the seven new temporary monitoring wells. Water

level measurements were taken from the survey mark on the northern side of the well casing.

Groundwater elevation data is provided in Table 5-3. A groundwater flow contour map is

provided as Figure 2-4.

5.5 SURVEYING

The northern side of each new temporary well casing was surveyed using a TOPCON Hiper V

global positioning system with FC-5000 data collection software. Positions were collected in the

applicable Universal Transverse Mercator zone projection with World Geodetic System 1984

datum (horizontal) and North American Vertical Datum 1988 (vertical). Surveying data were

collected on 04 November 2021 and are provided in Appendix B3.

5.6 INVESTIGATION-DERIVED WASTE

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

generated during the SI is considered non-hazardous waste and was managed in accordance with

the UFP-QAPP Addendum (EA/Wood, 2021a).

Soil IDW (i.e., soil cuttings) and liquid IDW (i.e., purge water, development water, and

decontamination fluids) generated during the SI activities were discharged directly to the ground

surface at a point slightly downgradient of the source of generation. The IDW was not sampled

and assumes the characteristics of the associated samples collected from that source location.

Geographic coordinates were collected using a Global positioning system (GPS) at each location

where IDW was placed (i.e., an IDW point). The IDW points are displayed on the figure in

Appendix B5.

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

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

field activities were disposed of at a licensed solid waste landfill.
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5.7 LABORATORY ANALYTICAL METHODS

Samples were analyzed by LC/MS/MS, compliant with QSM Version 5.3 Table B-15, at

Eurofins in Lancaster, Pennsylvania, a DoD ELAP and NELAP-certified laboratory.

Soil samples were also analyzed for TOC using EPA Method 9060A, pH by EPA Method

9045D, and grain size using ASTM Method D-422.

5.8 Deviations from SI UFP-QAPP Addendum

Deviations from the UFP-QAPP Addendum occurred based on conditions encountered during

field activities. These deviations were discussed between WSP, EA, ARNG, and USACE. One

deviation from the UFP-QAPP Addendum is noted below:

 The location of AOI01-02 was adjusted approximately 80 ft northeast of the proposed

location to avoid a potential conflict with an underground watermain in that area. The

new location was in a low point of a drainage swale that is adjacent to the concrete apron.

Facility personnel noted that this was likely the drainage path of any foam that would

have escaped Building 3410. A field change request form documenting the relocation

was submitted to USACE and ARNG on 2 November 2021. The approved field change

request form is included in Appendix B4.
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Table 5-1. Samples by Medium

Bismarck AASF #1, Bismarck, North Dakota

Site Inspection Report

Sample Identification

Sample

Collection

Date

Sample Depth

(ft bgs)

PFAS(LC/MS/MScompliant with QSM5.3 Table B-15)TOC(EPA Method 9060A)pH (EPA Method9045D)Grain Size (ASTMD422)

Comments

 Soil Samples

AOI01-02-SB-0-2 11/02/2021 0-2 X

AOI01-02-SB-3-4 11/02/2021 3-4 X

AOI01-02-SB-5-6 11/02/2021 5-6 X

AOI01-03-SB-0-2 11/02/2021 0-2 X MS/MSD Collected

AOI01-03-SB-2-4 11/02/2021 2-4 X X X

AOI01-03-SB-4-5 11/02/2021 4-5 X

AOI01-03-SB-7-8 11/02/2021 7-8 X

AOI01-04-SB-0-2 11/02/2021 0-2 X Parent Sample of

AOI01-SB-DUP01

AOI01-SB-DUP01 11/02/2021 0-2 X Field Duplicate

AOI01-04-SB-4-5 11/02/2021 4-5 X

AOI01-04-SB-9-10 11/02/2021 9-10 X

Groundwater Samples

AOI01-01-GW 11/03/2021 X MS/MSD Collected

AOI01-02-GW 11/03/2021 X

AOI01-03-GW 11/03/2021 X

AOI01-04-GW 11/03/2021 X

AOI01-05-GW 11/03/2021 X

AOI01-06-GW 11/03/2021 X Parent Sample of

AOI01-GW-DUP01

AOI01-GW-DUP01 11/03/2021 X

BAASF-01-GW 11/03/2021 X

Blank Samples

BAASF-EB-01-HA 11/02/2021 X Equipment Blank

Collected from Hand

Auger

BAASF-FB-01 11/03/2021 X Field Blank

BAASF-EB-02-WLM 11/03/2021 X Equipment Blank

Collected from Water

Level Meter

Notes:

ASTM = American Society for Testing and Materials

bgs = below ground surface

EB = equipment blank

FB = field blank

ft = feet

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MS/MSD = matrix spike/ matrix spike duplicate

QSM = Quality Systems Manual

TOC = total organic carbon

USEPA = United States Environmental Protection Agency
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Table 5-2. Soil Boring Depths and Temporary Well Screen Intervals

Bismarck AASF #1, Bismarck, North Dakota

Site Inspection Report

Area of Interest Boring Location

Soil Boring Depth

(ft bgs)

Temporary Well

Screen Interval

(ft bgs)

1

AOI01-01 15.0 10.0 – 15.0

AOI01-02 11.5 6.5 – 11.5

AOI01-03 14.0 9.0 – 14.0

AOI01-04 15.0 10.0 – 15.0

AOI01-05 15.0 10.0 – 15.0

AOI01-06 12.0 7.0 – 12.0

BAASF-01 13.0 8.0 – 13.0

Notes:

bgs = below ground surface

ft = feet
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Table 5-3. Groundwater Elevation

Bismarck AASF #1, Bismarck, North Dakota

Site Inspection Report

Monitoring Well

ID

Top of Casing Elevation

(ft NAVD88)

Depth to Water

(ft btoc)

Depth to Water

(ft bgs)

Groundwater Elevation

(ft NAVD88)

AOI01-01 1650.843 9.70 7.01 1641.14

AOI01-02 1651.646 10.92 7.22 1640.72

AOI01-03 1651.978 10.26 10.32 1641.71

AOI01-04 1651.351 9.53 9.82 1641.82

AOI01-05 1650.601 8.49 8.39 1642.11

AOI01-06 1649.472 9.05 6.83 1640.42

BAASF-01 1651.989 10.23 8.98 1641.76

Notes:

bgs = below ground surface

btoc = below top of casing

ft = feet

NAVD88 = North American Vertical Datum 1988
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Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

Figure 5-1

Site Inspection Sample Locations

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3410

AOI 1: Main Hangar

3420

C-12 Hangar

3407

3409 Simulator Storage

Storage

3408

UEVS

3400

Security Shack

Hazardous

Material Room

Maintenance Room

Culvert Ultimately 

Discharges into Apple Creek

3

ND

^_
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6. SITE INSPECTION RESULTS

This section presents the analytical results of the SI. The SLs used in this evaluation are

presented in Section 6.1 and Table 6-1. A discussion of the results for each AOI is provided in

Sections 6.2, 6.3 and 6.4. Tables 6-2 through 6-5 present results in soil or groundwater for the

relevant compounds. Tables that contain all results are provided in Appendix F, and the

laboratory reports are provided in Appendix G.

6.1 SCREENING LEVELS

The DoD has adopted a policy to retain facilities in the CERCLA process based on risk-based

SLs for soil and groundwater, as described in a memorandum from the OSD (Assistant Secretary

of Defense, 2022). The ARNG program under which this SI was performed follows this DoD

policy. Should the maximum concentration for sampled media exceed the SLs established in the

OSD memorandum, the AOI will proceed the next phase under CERCLA. The SLs established

in the OSD memorandum apply to the five compounds presented on Table 6-1.

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

Analyte2

Residential 0-2 ft bgs

(Soil)

(μg/kg)1

0-2 ft bgs

Industrial / Commercial

Composite Worker 2-15 ft bgs

(Soil)

(μg/kg) 1

2-15 ft bgs

Tap Water

(Groundwater)

(ng/L) 1

PFOA 19 250 6

PFOS 13 160 4

PFBS 1,900 25,000 601

PFHxS 130 1,600 39

PFNA 19 250 6

Notes:

1. Assistant Secretary of Defense. July 2022. Risk Based Screening Levels in Groundwater and Soil using

U.S. Environmental Protection Agency’s (EPA’s) Regional Screening Level Calculator. Hazard Quotient

(HQ)=0.1. May 2022.

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

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

during the PA and revised based on SI findings, the presence of HFPO-DA is not anticipated at the facility

because HFPO-DA is generally not a component of MIL-SPEC AFFF and based on its history including

distribution limitations that restricted use of GenX, it is generally not a component of other products the

military used. In addition, it is unlikely that GenX would be an individual chemical of concern in the

absence of other PFAS.

Abbreviations:

g/kg = microgram(s) per kilogram

bgs = below ground surface

ft = feet

ng/L = nanogram(s) per liter

The data in the subsequent sections are compared against the SLs presented in Table 6-1. The

SLs for groundwater are based on direct ingestion. The SLs for soil are based on incidental

ingestion and are applied to the depth intervals reasonably anticipated to be encountered by the

receptors identified at the Facility: the residential scenario is applied to surface soil results (0 to 2
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feet bgs) and the industrial/commercial worker scenario is applied to shallow subsurface soil

results (2 to 15 feet bgs). The SLs are not applied to deep subsurface soil results (>15 feet bgs)

because 15 feet is the anticipated limit of construction activities.

6.2 SOIL PHYSICOCHEMICAL ANALYSES

To provide basic soil parameter information, soil samples were analyzed for TOC, pH, and grain

size, which are important for evaluating transport through the soil medium. Appendix E contains

the results of the TOC, pH, and grain size sampling.

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

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

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

lipophobic effects, electrostatic interactions, and interfacial behaviors. At relevant environmental

pH values, certain PFAS are present as organic anions, and are therefore relatively mobile in

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

be present in soil or sediment (Higgins and Luthy, 2006; Guelfo and Higgins, 2013). When

sufficient organic carbon is present, organic carbon normalized distribution coefficients (Koc

values) can help in evaluating transport potential, though other geochemical factors (for example,

pH and presence of polyvalent cations) may also affect PFAS sorption to solid phases (ITRC,

2018).

6.3 AOI 1

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

AOI 1: Main Hangar. The soil and groundwater results are summarized in Table 6-2 through

Table 6-5. Soil and groundwater results are presented on Figure 6-1 through Figure 6-7.

6.3.1 AOI 1 Soil Analytical Results

Soil samples were collected from three boring locations associated with AOI 1 during the SI.

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Tables 6-2 through 6-4

summarize the soil results.

Surface soil (0 to 2 ft bgs) was sampled from boring locations AOI01-02 through AOI01-04,

with a duplicate surface soil sample collected at AOI01-04. Soil was also sampled from shallow

subsurface soil (3 to 5 ft bgs) and deep subsurface soil intervals (5 to 10 ft bgs) from boring

locations AOI01-02 through AOI01-04.

PFOS was detected in surface soil above the SL with a maximum concentration of 26 μg/kg

(AOI01-04 duplicate). PFHxS and PFOA were detected in surface soil at concentrations below

their respective SLs. PFHxS was detected in two of the four surface soil samples at locations

AOI01-02 and AOI01-04 (duplicate sample only) at a maximum concentration of 0.36 μg/kg.

PFOA was detected in two of the four surface soil samples at location AOI01-04 (and its

duplicate) at maximum concentration of 0.38 J μg/kg, where J denotes an estimated

concentration. PFBS and PFNA were not detected in the surface soil samples.
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PFHxS and PFOS were detected in shallow subsurface soil at concentrations below their

respective SLs. PFHxS was detected in one of three locations (AOI01-04) at 1.1 μg/kg. PFOS

was detected in one of three locations (AOI01-04) at 1.4 J μg/kg. PFOA, PFBS and PFNA were

not detected in the shallow subsurface soil samples.

PFOS was detected in deep subsurface soil at concentrations below the SLs. PFOS was detected

in one of three locations (AOI01-04) at 6.3 μg/kg. PFOA, PFBS, PFHxS and PFNA were not

detected in the deep subsurface soil samples.

6.3.2 AOI 1 Groundwater Analytical Results

Groundwater samples were collected from seven temporary wells associated with AOI 1 during

the SI. Figure 6-6 and Figure 6-7 presents the ranges of detections in groundwater. Table 6-5

summarizes the groundwater results.

Groundwater was sampled from temporary monitoring well locations AOI01-01 through AOI01-

06, BAASF-01, with a duplicate groundwater sample collected at AOI01-06. PFOA, PFOS and

PFHxS were detected at concentrations exceeding their respective SLs. PFOS was detected in

seven of the eight groundwater samples at concentrations that ranged from 0.78 ng/L to 2500

ng/L. PFHxS was detected in all eight groundwater samples at concentrations that ranged from

1.1 ng/L to 370 ng/L. PFOA was detected in all eight groundwater samples at concentrations that

ranged from 1.2 ng/L to 20 ng/L. PFBS was detected in all eight groundwater samples at

concentrations below the SL that ranged from 0.61 ng/L to 55 ng/L. PFNA was detected at one

temporary monitoring well location (AOI01-06) at 0.52 ng/L, below the SL.

6.3.3 Conclusions

Based on the results of the SI, PFOS was detected in surface soil above the SL at AOI01-04. No

other soil samples exceeded the SLs. PFOA, PFOS and PFHxS were detected in groundwater at

concentrations above their respective SLs. Sample location AOI01-04 had the highest

concentration of PFOS in groundwater. Based on the exceedances of the SLs in groundwater and

surface soil, further evaluation at AOI 1 is warranted.

The regional groundwater flow direction within the surficial aquifer was inferred to be easterly

based on the location of surficial water bodies, namely Apple Creek located east of the facility.

BAASF-01 was intended as an upgradient boundary well based on the inferred regional

groundwater flow toward the east. Synoptic water level measurements taken from temporary

wells during the SI fieldwork indicated that the local groundwater flow is northeasterly. As such,

BAASF-01 is actually located cross-gradient to AOI 1. The PFOS concentration at the most

downgradient temporary well (AOI01-02) was above the SL. Based on a review of the North

Dakota Department of Water Resources MapServices, it was noted that there are four wells (one

domestic well, two irrigation wells, and an unknown well) that are within approximately one

mile of the facility and potentially downgradient.
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6.4 AOI 2

Following the SI fieldwork, photographs were found showing that a TriMax30TM fire

extinguisher was stored near the Fuel Point for emergencies. The photographs of the

TriMax30TM were taken in 2011. Subsequent photographs of the area indicate that the fire

extinguisher was replaced sometime between 2011 and 2020. AOI 2 will be investigated as part

of the RI. Photographs are included in Appendix C.

6.5 AOI 3

Following the SI fieldwork, photographs were found showing that a TriMax30TM fire

extinguisher was stored near the Fuel Truck Parking for emergencies. The photographs of the

TriMax30TM were taken in 2011 and 2017. Subsequent photographs of the area indicate that the

fire extinguisher was replaced sometime between 2017 and 2020. AOI 3 will be investigated as

part of the RI. Photographs are included in Appendix C.
Table 6-2

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

Site Inspection Report

Bismarck AASF #1

Depth

Analyte OSD Screening Level 1 Result Qual Result Qual Result Qual R

PFBS 1900 ND U ND U ND U 

PFHxS 130 0.23 J ND U ND U 

PFNA 19 ND U ND U ND U 

PFOA 19 ND U ND U 0.37 J 

PFOS 13 ND U ND U 19 

Notes Chemical AbbreviationsGray Fill Detected concentration exceeded OSD Screening Levels PFBS per

PFHxS per

References PFNA per

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated PFOA per

for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s PFOS per

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soil are

based on residential scenario for incidental ingestion of contaminated soil.

Interpreted Qualifiers

J = Estimated concentration.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAASF Army Aviation Support FacilityAOI Area of InterestDUP duplicate

HQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the Defense

QSM Quality Systems Manual

PFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection Agency

Qual interpreted qualifier

Area of Interest

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

AOI01

0 - 2 ft 0 - 2 ft 0 - 2 ft 

A

A

Sample ID AOI01-02-SB-0-2 AOI01-03-SB-0-2 AOI01-04-SB-0-2

Location ID AOI01-02

Sample Date 11/2/2021 11/2/2021 11/2/2021

AOI01-03 AOI01-04

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Table 6-3

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

Site Inspection Report

Bismarck AASF #1

Analyte OSD Screening Level 1 Result Qual Result Qual Result Qual

PFBS 25000 ND U ND U ND UPFHxS 1600 ND U ND U 1.1PFNA 250 ND U ND U ND UPFOA 250 ND U ND U ND UPFOS 160 ND U ND U 1.4 J

Notes Chemical AbbreviationsGray Fill Detected concentration exceeded OSD Screening Levels PFBS 

PFHxS 

References PFNA 

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated PFOA  for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s PFOS Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soil arebased on Industrial/Commercial Composite Worker scenario for incidental ingestion of contaminated soil.Interpreted Qualifiers

J = The result is an estimated quantity.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAASF Army Aviation Support FacilityAOI Area of InterestDUP duplicateHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

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

Area of Interest

Depth

AOI01

3 - 4 ft 4 - 5 ft 4 - 5 ft

AOI01-04

AOI01-04-SB-4-5

11/2/2021

Location ID AOI01-02 AOI01-03

Sample ID AOI01-02-SB-3-4 AOI01-03-SB-4-5

Sample Date 11/2/2021 11/2/2021

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Table 6-4

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

Site Inspection Report

Bismarck AASF #1

Analyte OSD Screening Level 1 Result Qual Result Qual Result Qual

PFBS 25000 ND U ND UJ ND UPFHxS 1600 ND U ND UJ ND UPFNA 250 ND U ND U ND UPFOA 250 ND U ND UJ ND UPFOS 160 ND U ND UJ 6.3

Notes Chemical AbbreviationsGray Fill Detected concentration exceeded OSD Screening Levels PFBS 

PFHxS 

References PFNA 

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated PFOA 

 for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s PFOS 

Regional Screening Level Calculator. HQ=0.1. May 2022. The screening levels for soil arebased on Industrial/Commercial Composite Worker scenario for incidental ingestion of contaminated soil.Interpreted Qualifiers

U = The analyte was not detected at a level greater than or equal to the adjusted DL.UJ = The analyte was not detected at a level greater than or equal to the adjusted DL.  However, the reported adjusted DL is approximate and may be inaccurate or imprecise.Acronyms and Abbreviationsμg/kg microgram(s) per kilogramAASF Army Aviation Support FacilityAOI Area of InterestDUP duplicateHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)OSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

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

AOI01-04

AOI01-04-SB-9-10

AOI01-03

Sample ID AOI01-02-SB-5-6 AOI01-03-SB-7-8

Area of Interest

Depth

AOI01

5 - 6 ft 7 - 8 ft 9 - 10 ft

11/2/2021

Location ID AOI01-02

Sample Date 11/2/2021 11/2/2021

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Table 6-5

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

Site Inspection Report

Bismarck AASF #1

Analyte Screening Level 1 Result Qual Result Qual Result Qual Result Qual Result Qua

 PFAS (ng/L)PFBS 601 0.61 J 7. 10 34 55 PFHxS 39 1.1 J 18 140 370 160 PFNA 6 ND U ND U ND U ND U ND U PFOA 6 1.4 J 1.4 J 9.2 20 11 PFOS 4 ND U 67 320 2500 1300 

Notes Gray Fill Detected concentration exceeded OSD Screening Levels 

References 

1. Assistant Secretary of Defense, July 2022. Risk Based Screening Levels Calculated 

 for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1 . May 2022. Groundwater screening levelsbased on residential scenario for direct ingestion of groundwater.Interpreted Qualifiers

J = Estimated concentration.U = The analyte was not detected at a level greater than or equal to the adjusted DL.Acronyms and AbbreviationsAASF Army Aviation Support FacilityAOI Area of InterestDUP duplicateHQ Hazard QuotientID identificationLCMSMS liquid chromatography with tandem mass spectrometryLOD limit of detectionLOQ limit of quantitationND analyte not detected above the LOD (LOD values are presented in Appendix F)ng/L nanogram(s) per literOSD Office of the Secretary of the DefenseQSM Quality Systems ManualPFAS per- and polyfluoroalkyl substancesSB soil boringUSEPA United States Environmental Protection AgencyQual interpreted qualifier

Area of Interest AOI01

AOI01-05-GW

Location ID AOI01-01 AOI01-02 AOI01-03 AOI01-04 AOI01-05

Sample Name AOI01-01-GW AOI01-02-GW AOI01-03-GW AOI01-04-GW

Sample Date 11/3/2021 11/3/2021 11/3/2021 11/2/2021 11/3/2021 

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Figure 6-1

PFOA Detections in Soil

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Shallow GroundwaterFlow Direction(November 2021)

G:\ANG\a_MXD\BismarkND\Analytical Results Figure\PFOA Detections in Soil.mxd - megan.cameron - 9/8/2022 - 1:25:48 PM

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Shallow (0-2')

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Figure 6-2

PFOS Detections in Soil

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Building

Stormwater Line

Sewer Line

!@ Manhole (Stormwater Line)

!@ Manhole (Sewer Line)

g"" Catch Basin

!< Oil Water Separator

ND

^_

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Shallow

Groundwater Flow

Direction (November

2021)

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Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

Date:................SEPTEMBER 2022

Prepared By:.......................WOOD

Prepared For:.....................USACE

Projection:......NAD 83 State Plane

Shallow (0-2')

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3

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Deep (5-10')

NOTES:

PFOS = perfluorooctanesulfonic acid

ND = Non-Detect

(μg/Kg) = Microgram(s) per Kilogram

Exceedances of the OSD SL are depicted 

with a yellow halo.

PFOS Results (μg/Kg)

!( ND

!( >ND - 13

!!( >13 - 160

!!( >160 - 1,600

!!( >1,600
Site Inspection Report

Bismarck Army Aviation Support Facility #1, North Dakota Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-16

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Figure 6-3

PFBS Detections in Soil

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Facility Data

Facility BoundaryPotential PFAS ReleaseArea of InterestBuilding

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Hydrology

Shallow GroundwaterFlow Direction(November 2021)

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Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

Shallow (0-2')

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PFBS Results(μg/Kg)

!( ND

!( >ND - 10

!!( >10 - 1,900

!!( >1,900 - 25,000 !!( >25,
Site Inspection Report

Bismarck Army Aviation Support Facility #1, North Dakota Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-18

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Figure 6-4

PFHxS Detections in Soil

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Facility BoundaryPotential PFAS ReleaseArea of InterestBuilding

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!< Oil Water Separator

Hydrology

Shallow GroundwaterFlow Direction(November 2021)

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Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

Shallow (0-2')

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Intermediate (3-5')

PFHxS Results(μg/Kg)

!( ND

!( >ND - 10

!!( >10 - 130

!!( >130 - 1,600 !!( >1,6
Site Inspection Report

Bismarck Army Aviation Support Facility #1, North Dakota Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-20

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Facility BoundaryPotential PFAS ReleaseArea of InterestBuilding

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Hydrology

Shallow GroundwaterFlow Direction(November 2021)

G:\ANG\a_MXD\BismarkND\Analytical Results Figure\PFNA Detections in Soil.mxd - megan.cameron - 9/8/2022 - 1:49:18 PM

Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

Figure 6-5

PFNA Detections in Soil

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Intermediate (3-5')

PFNA Results(μg/Kg)

!( ND

!( >ND - 19

!!( >19 - 250

!!( >250 - 2,500 !!( >2,5
Site Inspection Report

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EA Engineering, Science, and Technology, Inc., PBC 6-22

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Figure 6-6

PFOA, PFOS, and PFBS Detections in Groundwater

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AOI01-01

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BAASF-01

3

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Facility BoundaryPotential PFAS ReleaseArea of InterestBuilding

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!@ Manhole (Sewer Line)g"" Catch Basin

!< Oil Water Separator

Hydrology

Shallow GroundwaterFlow Direction(November 2021)

G:\ANG\a_MXD\BismarkND\Analytical Results Figure\PFOS_PFOA_PFBS_Detections in GW.mxd - megan.cameron - 9/9/2022 - 7:26:46 PM

Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

PFOA

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AOI01-01

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AOI01-06

BAASF-01

3

0 150

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PFOS

NOTES:PFOS = perfluoPFOA = perfluoPFBS = perfluoND = Non-Deteng/L = nanogramExceedances o

PFOA Results (ng/L)

!( ND

!( >ND - 6

!!( >6 - 40

!!( >40 - 70

!!( >70

PFOS Results (ng

!( ND

!( >ND - 4

!!( >4 - 40

!!( >40 - 70

!!( >70
Site Inspection Report

Bismarck Army Aviation Support Facility #1, North Dakota Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-24

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Figure 6-7

 PFHxS and PFNA Detections in Groundwater

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BAASF-01

3

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Facility Data

Facility BoundaryPotential PFAS ReleaseArea of InterestBuilding

Stormwater LineSewer Line

!@ Manhole (Sewer Line)g"" Catch Basin

!< Oil Water Separator

Hydrology

Shallow GroundwaterFlow Direction(November 2021)

G:\ANG\a_MXD\BismarkND\Analytical Results Figure\PFHxS_PFNA_Detections in GW.mxd - megan.cameron - 11/15/2022 - 3:56:43 PM

Army National Guard Site Inspections

Site Inspection Report

Bismarck AASF #1, North Dakota

PFHxS

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NOTESPFHxS PFNA ND = Nng/L = Exceedwith a 

PFHxS Results (ng/L)

!( ND

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!!( >39 - 100

!!( >100 - 1,000

!!( >1,000
Site Inspection Report

Bismarck Army Aviation Support Facility #1, North Dakota Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-26

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Site Inspection Report

Bismarck Army Aviation Support Facility #1, North Dakota Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 7-1

7. EXPOSURE PATHWAYS

The Conceptual Site Model (CSM) for AOI 1, revised based on the SI findings, is presented on

Figure 7-1. Additionally, preliminary CSMs for AOI 2 and AOI 3 are included as Figure 7-2

and Figure 7-3, respectively. AOI 2 and AOI 3 were identified as potential release areas

following the SI fieldwork based on 2011 and 2017 photographs that showed TriMax30TM fire

extinguishers had occasionally been stored in those areas. AOI 2 and AOI 3 will be investigated

as part of the RI.

Please note that while the CSM discussion assists in determining if a receptor may be impacted,

the decision to move from SI to RI or interim action is determined based upon exceedances of

the SLs for the relevant compounds and whether the release is more than likely attributable to the

DoD. A CSM presents the current understanding of the Facility conditions with respect to known

and suspected sources, potential transport mechanisms and migration pathways, and potentially

exposed human receptors. A human exposure pathway is considered potentially complete when

the following conditions are present:

1. Contaminant source;

2. Environmental fate and transport;

3. Exposure point;

4. Exposure route; and

5. Potentially exposed populations.

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

circle symbol to represent an incomplete exposure pathway. Areas with no identified complete

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

complete if the relevant compounds are detected, in which case the CSM figure uses a half-filled

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

filled circle symbol is used to indicate when a potentially complete exposure pathway has

detections of the relevant compounds above the SLs. Areas with an identified potentially

complete pathway and a complete pathway may warrant further investigation. Although the

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

for future study in a RI or no action at this time is based on the comparison of the SI analytical

results for the relevant compounds to the SLs.

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

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

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

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

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

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

construction workers, off-facility residents, off-facility recreational user, and potential

trespassers.
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7.1 SOIL EXPOSURE PATHWAY

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

between the source and potential receptors at each AOI based on the aforementioned criteria.

7.1.1 AOI 1

AOI 1 is the Main Hangar and the immediate surrounding area (Figure 3-1). There were no

documented releases of PFAS to the ground surface (outside the hangar), but PFAS-containing

fire suppressants were stored at the Facility, and there is the potential for PFAS releases inside

and immediately surrounding the Main Hangar. PFOS was detected in the surface soil at

concentrations above SLs at one boring location completed outside an overhead door on the west

side of the Main Hangar (AOI01-04). Surface soil also had detections of PFOA and PFHxS that

were below SLs. Based on the results of the SI at AOI 1, direct contact with surface soil could

result in site worker, construction worker, and/or trespasser exposure to PFOS, PFOA, and

PFHxS via inhalation of dust or incidental ingestion of soil particles. Subsurface soil at AOI 1

had detections of PFOS and PFHxS that were below SLs. Construction workers could contact

constituents in subsurface soil via incidental ingestion and inhalation of dust; therefore, the

subsurface soil exposure pathway for construction workers is potentially complete. A recent

construction project to improve a gravel parking area, which included the installation of storm

sewer, fencing, and pavement, was located outside (and southwest) of AOI 1. The CSM for AOI

1 is presented in Figure 7-1.

7.1.2 AOI 2

AOI 2 is the Fuel Point (Figure 3-1). There were no documented releases of PFAS to the ground

surface. Photographs from 2011 showed that PFAS-containing fire suppressants were stored in

the area. Potential releases may have occurred on paved surfaces. PFAS releases to the paved

surfaces could have impacted soil via cracks in the pavement of joints between areas that are

paved. Direct contact with surface soil could result in site worker, construction worker, and/or

trespasser exposure to PFAS via inhalation of dust or incidental ingestion of soil particles. Direct

contact with subsurface soil (during excavation activities) could result in construction worker

exposure to PFAS via inhalation of dust or incidental ingestion of soil particles. A recent

construction project to improve a gravel parking area, which included the installation of storm

sewer, fencing, and pavement, was located outside (and northwest) of AOI 2. Further assessment

will be conducted during the RI. The preliminary CSM is presented in Figure 7-2.

7.1.3 AOI 3

AOI 3 is the Fuel Truck Parking (Figure 3-1). There were no documented releases of PFAS to

the ground surface. Photographs from 2011 and 2017 showed that PFAS-containing fire

suppressants were stored in the grassy area next to the paved Fuel Truck Parking area. Potential

releases may have directly impacted soil or could have been released on paved surfaces. PFAS

releases to the paved surfaces could have impacted soil via cracks in the pavement of joints

between areas that are paved. Direct contact with surface soil could result in site worker,

construction worker, and/or trespasser exposure to PFAS via inhalation of dust or incidental

ingestion of soil particles. Direct contact with subsurface soil (during excavation activities) could
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result in construction worker exposure to PFAS via inhalation of dust or incidental ingestion of

soil particles. A recent construction project to improve a gravel parking area, which included the

installation of storm sewer, fencing, and pavement, was located outside (and northwest) of AOI

2. Further assessment will be conducted during the RI. The preliminary CSM is presented in

Figure 7-3.

7.2 GROUNDWATER EXPOSURE PATHWAY

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

exists between the source and potential receptors at each AOI based on the aforementioned

criteria.

7.2.1 AOI 1

AOI 1 is the Main Hangar and the immediate surrounding area (Figure 3-1). There were no

documented releases of PFAS to the ground surface outside the hangar, but PFAS-containing fire

suppressants were stored at the Facility and there is the potential for PFAS releases inside and

immediately surrounding the Main Hangar. PFOS was detected in the groundwater at all

sampling locations except for one (AOI01-01). The concentration of PFOS in groundwater

exceeded the SLs at five of the seven sample locations. PFOA and PFHxS were detected in the

groundwater at all 7 sampling locations and the concentrations detected exceeded their respective

SLs at four of the seven sample locations. PFBS was detected in the groundwater at all 7

sampling locations at concentrations that were below the SLs. PFNA was detected in the

groundwater at one sampling location at a concentration below the SL. Based on the results of

the SI at AOI 1, ground disturbing activities that extend to the water table (approximately 15 ft

bgs) could result in construction worker exposure to relevant compounds via incidental

ingestion.

The regional groundwater flow direction within the surficial aquifer was inferred to be easterly

based on the location of surficial water bodies, namely Apple Creek located east of the facility.

BAASF-01 was intended as an upgradient boundary well based on the inferred regional

groundwater flow toward the east. Synoptic water level measurements taken from temporary

wells during the SI fieldwork indicated that the local groundwater flow is northeasterly. As such,

BAASF-01 is actually located cross-gradient to AOI 1. The PFOS concentration at the most

downgradient temporary well (AOI01-02) was above the SL. Based on a review of the North

Dakota Department of Water Resources MapServices, it was noted that there are four wells (one

domestic well, two irrigation wells, and an unknown well) that are within approximately one

mile of the facility and potentially downgradient. Potential resident receptors downgradient of

the AOI could also be exposed by ingestion of groundwater. The concentration at the potential

point of exposure for off-facility residents is not known, therefore, the exposure pathway for

ingestion is potentially complete for off-facility residential receptors. The CSM for AOI 1 is

presented in Figure 7-1.

7.2.2 AOI 2

AOI 2 is the Fuel Point (Figure 3-1). There were no documented releases of PFAS to the ground

surface. Photographs from 2011 showed that PFAS-containing fire suppressants were stored in
Site Inspection Report

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the area. Potential releases may have occurred on paved surfaces. PFAS releases to the paved

surfaces could have impacted soil via cracks in the pavement of joints between areas that are

paved. PFAS releases to the soil can migrate to groundwater, as such, ground disturbing

activities that extend to the water table (approximately 15 ft bgs) could result in construction

worker exposure to PFAS via incidental ingestion. Potential resident receptors downgradient of

the AOI 2 could also be exposed by ingestion of groundwater. Further assessment will be

conducted during the RI. The preliminary CSM is presented in Figure 7-2.

7.2.3 AOI 3

AOI 3 is the Fuel Truck Parking (Figure 3-1). There were no documented releases of PFAS to

the ground surface. Photographs from 2011 and 2017 showed that PFAS-containing fire

suppressants were stored in the grassy area next to the paved Fuel Truck Parking area. Potential

releases may have directly impacted soil or could have been released on paved surfaces. PFAS

releases to the paved surfaces could have impacted soil via cracks in the pavement of joints

between areas that are paved. PFAS releases to the soil can migrate to groundwater, as such,

ground disturbing activities that extend to the water table (approximately 15 ft bgs) could result

in construction worker exposure to PFAS via incidental ingestion. Potential resident receptors

downgradient of the AOI 3 could also be exposed by ingestion of groundwater. Further

assessment will be conducted during the RI. The preliminary CSM is presented in Figure 7-3.

7.3 SURFACE WATER AND SEDIMENT EXPOSURE PATHWAY

There is no surface water located at the AASF, however, stormwater at the Facility is managed

by a series of grassed trenches and small retention basins before being discharged to Apple

Creek, and ultimately to the Missouri River (AECOM, 2020). Stormwater has the potential to

transport AFFF or PFAS-impacted soils to water bodies. The ingestion exposure pathway for

offsite surface water and sediment is considered potentially complete for recreational users of

these rivers. Human consumption of fish potentially affected by PFAS from the rivers is also

possible. No surface water or sediment samples were collected as part of the SI.

7.3.1 AOI 1

There were no documented releases of PFAS to the ground surface outside the hangar, but

PFAS-containing fire suppressants were stored at the Facility, and there is the potential for PFAS

releases inside and immediately surrounding the Main Hangar. There are no documented

incidents of PFAS-containing (or potentially containing) fire suppressants being discharged to

the stormwater system. PFOS was detected in the surface soil at concentrations above SL at one

boring location completed outside an overhead door on the west side of the Main Hangar

(AOI01-04). Due to the presence of PFAS in soil, there is the potential for stormwater to

transport PFAS-impacted soil to Apple Creek, and ultimately the Missouri River and expose the

potential recreational user by ingestion of surface water and/or fish potentially affected by PFAS.

The CSM is presented in Figure 7-1.
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7.3.2 AOI 2

AOI 2 is the Fuel Point (Figure 3-1). There were no documented releases of PFAS to the ground

surface. Photographs from 2011 showed that PFAS-containing fire suppressants were stored in

the area. Potential releases may have occurred on paved surfaces. PFAS releases to the paved

surfaces could have impacted soil via cracks in the pavement of joints between areas that are

paved. There is the potential for stormwater to transport PFAS-impacted soil to Apple Creek, and

ultimately the Missouri River and expose the potential recreational user by ingestion of surface

water and/or fish potentially affected by PFAS. Further assessment will be conducted during the

RI. The preliminary CSM is presented in Figure 7-2.

7.3.3 AOI 3

AOI 3 is the Fuel Truck Parking (Figure 3-1). There were no documented releases of PFAS to

the ground surface. Photographs from 2011 and 2017 showed that PFAS-containing fire

suppressants were stored in the grassy area next to the paved Fuel Truck Parking area. Potential

releases may have directly impacted soil or could have been released on paved surfaces. PFAS

releases to the paved surfaces could have impacted soil via cracks in the pavement of joints

between areas that are paved. There is the potential for stormwater to transport PFAS-impacted

soil to Apple Creek, and ultimately the Missouri River and expose the potential recreational user

by ingestion of surface water and/or fish potentially affected by PFAS. Further assessment will

be conducted during the RI. The preliminary CSM is presented in Figure 7-3.
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Notes:

1. The resident and recreational user refers to 

off-site receptors.

2. Inhalation of dust for off-site receptors is 

highly unlikely. Figure 7-1

Conceptual Site Model

Bismarck AASF #1 Main 

RECEPTO

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1,2 

AOI 1 PFAS in Surface Soil

Human 

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne 

Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Ingestion

Ingestion

Ingestion

Ingestion

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

Hangar Release, 

TriMaxTM Fire 

Extinguishers, Bulk 

AFFF Storage

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

Inhalation 

of Dust

Site 

Worker

Construction 

Worker Resident1,2 

LEGEND

Flow Chart ContinuesIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL
Site Inspection Report

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Figure 

Conceptual Site 

Bismarck AASF 

RECEPTO

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1,2 

AOI 2* PFAS in Surface Soil

Human 

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne 

Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Ingestion

Ingestion

Ingestion

Ingestion

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

TriMaxTM Fire 

Extinguisher 

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

Inhalation 

of Dust

Site 

Worker

Construction 

Worker Resident1,2 

LEGEND

Flow Chart ContinuesIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL

Notes:* Assessment of pathways will be conducted during the RI1. The resident and recreational user refers to off-site 

receptors.

2. Inhalation of dust for off-site receptors is highly unlikely.
Site Inspection Report

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EA Engineering, Science, and Technology, Inc., PBC 7-10

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Figur

Conceptual Site 

Bismarck AASF #1 

RECEPTO

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1,2 

AOI 3* PFAS in Surface Soil

Human 

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne 

Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Ingestion

Ingestion

Ingestion

Ingestion

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

TriMaxTM Fire 

Extinguisher 

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

Inhalation 

of Dust

Site 

Worker

Construction 

Worker Resident1,2 

LEGEND

Flow Chart ContinuesIncomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SL

Notes:* Assessment of pathways will be conducted during the RI1. The resident and recreational user refers to off-site 

receptors.

2. Inhalation of dust for off-site receptors is highly unlikely.
Site Inspection Report

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EA Engineering, Science, and Technology, Inc., PBC 7-12

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Site Inspection Report

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EA Engineering, Science, and Technology, Inc., PBC 8-1

8. SUMMARY AND OUTCOME

This section summarizes SI activities and findings. The most significant findings are summarized

in this section and are reproduced directly or abstracted from information contained in this

report. The outcome provides general and comparative interpretations of the findings relative to

the SLs.

8.1 SI ACTIVITIES

The SI field activities at the Facility were conducted from 01 to 03 November 2021. The SI field

activities included soil and groundwater sampling. Field activities were conducted in accordance

with the UFP-QAPP Addendum (EA/Wood, 2021a), except as previously noted in Section 5.8.

To fulfill the project DQOs set forth in the approved SI UFP-QAPP Addendum (EA/Wood,

2021a), samples were collected and analyzed for a subset of PFAS by LC/MS/MS compliant

with QSM 5.3 Table B-15 as follows.

 Nine soil grab samples from three boring locations;

 Seven grab groundwater samples from seven temporary well locations; and

 Five (5) QA/QC samples.

An SI is conducted when the PA determines an AOI exists based on probable use, storage, and/or

disposal of PFAS-containing materials. The SI includes multi-media sampling at AOIs to

determine whether or not a release has occurred. The SI may conclude further investigation is

warranted, a removal action is required to address immediate threats, or no further action is

required. Additionally, the CSMs were refined to assess whether a potentially complete pathway

exists between the source and potential receptors for potential exposure at the AOIs, which are

described in Section 7.

8.2 OUTCOME

Based on the results of this SI, further evaluation in the form of a RI is warranted for AOI 1.

Based on the CSMs developed and revised based on the SI findings, there is potential for

exposure to residential drinking water receptors from AOI 1 from sources on the Facility

resulting from historical DoD activities.

Sample analytical concentrations collected during the SI were compared against the project SLs

for soil and groundwater, as described in Table 6-1. The following bullets summarize the SI

results relative to the SLs:

At AOI 1:

 PFOS, PFOA, and PFHxS in groundwater exceeded their respective SLs. PFOS exceeded

the SL of 4 ug/L with a maximum concentration of 2,500 ng/L at AOI01-04. PFOA

exceeded the SL of 6 ug/L with a maximum concentration of 20 ng/L at AOI01-04.
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PFHxS exceeded the SL of 6 ug/L with a maximum concentration of 370 ng/L at AOI01-

04. Based on the results of the SI, further evaluation of AOI 1 is warranted in the RI.

 PFOS in surface soil exceeded the screening level of 13 μg/kg at one location with a

concentration of 19 μg/kg. Based on the results of the SI, further evaluation of AOI 1 is

warranted in the RI.

At AOI 2:

 During preparation of the SI report, it was discovered that a TriMax30TM fire extinguisher

had occasionally been stored at the Fuel Point since at least 2011. Based on this information,

the Fuel Point was designated as AOI 2 and will also be investigated as part of the RI.

At AOI 3:

 During preparation of the SI report, it was discovered that a TriMax30TM fire extinguisher

had occasionally been stored at the Fuel Truck Parking since at least 2011. Based on this

information, the Fuel Truck Parking was designated as AOI 3 and will also be investigated as

part of the RI.

At the boundary:

 The locations of temporary monitoring wells that were positioned to evaluate potential

upgradient sources were based on the expected easterly regional groundwater flow. Synoptic

water levels measured during the SI indicated a northeasterly groundwater flow. As such,

these monitoring wells did not provide the data to assess upgradient impacts and the

evaluation of potential off-facility PFAS sources remains incomplete. This will be evaluated

during the RI.

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

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

the CSM developed during the PA and revised based on SI findings, the presence of HFPO-DA

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

AFFF and based on its history including distribution limitations that restricted use of GenX, it is

generally not a component of other products the military used. In addition, it is unlikely that

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

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

be considered for further investigation under CERCLA and undergo an RI.
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Table 8-1. Summary of Site Inspection Findings and Recommendations

AOI

Potential Release

Area

Soil –

Source Area

Groundwater –

Source Area

Groundwater –

Facility Boundary Future Action

1 Main Hangar Proceed to RI

2 Fuel Point TBD TBD TBD Proceed to RI

3 Fuel Truck Parking TBD TBD TBD Proceed to RI

Legend:

 = Detected; exceedance of screening levels

 = Detected; no exceedance of screening levels

 = Not detected

Abbreviations:

TBD = to be determined during RI

RI = remedial investigation
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