FINAL

Site Inspection Report

Central Oregon Unit Training Equipment Site

Redmond, Oregon

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

May 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................................................................................................................ iv

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

2.2.4 Climate.................................................................................................. 2-4

2.2.5 Current and Future Land Use................................................................ 2-4

2.2.6 Sensitive Habitat and Threatened/Endangered Species........................ 2-5

2.3 History of PFAS Use ........................................................................................... 2-5

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

3.1 AOI 1 – Wash Rack Bay...................................................................................... 3-1

3.2 AOI 2 – Wastewater Discharge Area................................................................... 3-1

3.3 Adjacent Sources ................................................................................................. 3-1

3.3.1 The Redmond Municipal Airport ......................................................... 3-1

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

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

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

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

4.4 Analytical Approach ............................................................................................ 4-1

4.5 Data Usability Assessment .................................................................................. 4-2

5. SITE INSPECTION ACTIVITIES.................................................................................. 5-1
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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 Groundwater Grab Sampling ............................................................................... 5-4

5.4 Surveying ............................................................................................................. 5-5

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

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

5.7 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 Conclusions........................................................................................... 6-3

6.4 AOI 2 .................................................................................................................. 6-3

6.4.1 AOI 2 Soil Analytical Results .............................................................. 6-3

6.4.1 Conclusions........................................................................................... 6-3

6.5 Potable supply well.............................................................................................. 6-3

6.5.1 Groundwater Analytical Results........................................................... 6-4

6.5.2 Conclusions........................................................................................... 6-4

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

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

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

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

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

7.2.1 Potable Supply Well ............................................................................. 7-3

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

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

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

9. REFERENCES ................................................................................................................ 9-1
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LIST OF APPENDICES

Appendix A. Data Usability Assessment and Validation Reports

Appendix B. Field Documentation

B1. Logs of Daily Notice of Field Activities

B2. Sampling Forms 

B3. Survey Data

B4. Field Change Request Form

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

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 3-1 Areas of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOS Detections in Soil

Figure 6-2 PFOA 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, COUTES
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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 Site Inspection Samples by Medium, COUTES, Oregon, Site Inspection Report

Table 5-2 Soil Boring Depths and Temporary Well Screen Intervals, COUTES, Oregon, Site

Inspection Report

Table 6-1 Screening Levels (Soil and Groundwater)

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

Oregon, Site Inspection Report

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

COUTES, Oregon, Site Inspection Report

Table 6-4 PFOA, PFOS, PFBS, PFHxS, and PFNA Results in Groundwater, COUTES, 

Oregon, Site Inspection Report

Table 8-1 Summary of Site Inspection Findings, Site Inspection Report, COUTES, 

Redmond, Oregon
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LIST OF ACRONYMS AND ABBREVIATIONS

°C Degrees Celsius

% Percent

μg/kg Microgram(s) per kilogram

AECOM AECOM Technical Services, Inc. 

AFFF Aqueous Film-Forming Foam

AOI Area of Interest

ARNG Army National Guard

ASTM ASTM International

bgs Below ground surface

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

COUTES Central Oregon Unit Training Equipment Site

CSM Conceptual site model

DA United States Department of the Army

DoD United States 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

EIS Extraction internal standards

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

EB Equipment Blank 

FB Field blank

FedEx Federal Express

ft Foot (feet)

HDPE High-density polyethylene

HFPO-DA Hexafluoropropylene oxide dimer acid

HQ Hazard Quotient

HUC Hydrologic Unit Code

IDW Investigation-derived waste

ISC Instrument sensitivity check

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
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MIL-SPEC military specification

MS Matrix spike

MSD Matrix spike duplicate

NELAP National Environmental Laboratory Accreditation Program 

ng/L Nanogram(s) per liter

No. Number

ODEQ Oregon Department of Environmental Quality

OMD Oregon Military Department

ORARNG Oregon Army National Guard

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

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

UFP Uniform Federal Policy 

USACE United States Army Corps of Engineers

USEPA United States Environmental Protection Agency

USGS United States Geological Survey

Wood Wood Environment & Infrastructure Solutions, Inc.

WSP WSP USA Environment & 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 this document, and the applicable 

Screening Levels (SLs) are provided below in Table ES-1. 

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

used, stored, disposed, or released historically (see Table ES-2 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 Central Oregon Unit Training Equipment Site 

(COUTES) in Redmond, Oregon and determined that no further evaluation under 

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) is 

warranted for AOI 1 and AOI 2. COUTES will also be referred to as the “Facility” throughout 

this report.

The Facility, operated by the Oregon ARNG (ORARNG), encompasses approximately 35.5

acres east of Redmond, Oregon. The Facility is located adjacent to and east of the Redmond 

Airport. The nearest metropolitan area is Redmond, Oregon, 2.2 miles west of the Facility 

(Figure 2-1). Parcels surrounding COUTES are undeveloped land on all boundaries, with the 

airport owning the land to the west. COUTES occupies 29.1 acres of land administered by the 

United States Army Corps of Engineers and licensed for use by the Oregon Military Department 

(OMD) since 1987. The remaining 6.4 acres that COUTES occupies is owned by the City of 

Redmond and has been used as a National Guard military facility since the lease to OMD began 

in 1973. Currently, the Facility is used for vehicle maintenance and warehouse storage. 

Historically, there was a firing range on the eastern portion of the Facility used for training 

purposes. The Facility includes a maintenance building, wash rack bay, warehouse, and inactive 

firing range. Directly outside of the Facility boundary are airport runways and taxiways to the 

west (AECOM, 2020). Access to the Facility is controlled.

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

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

Based on the results of this SI, no further evaluation under CERCLA is warranted for each of the 

two AOIs at this time. 

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 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.

Abbreviations:

μg/kg = microgram(s) per kilogram

bgs = below ground surface

ng/L = nanogram(s) per liter

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

AOI Potential Release Area

Soil – 

Source Area

Groundwater – 

Source Area Future Action

1 Wash Rack Bay Not Sampled No further action

2 Wastewater Discharge 

Area Not Sampled No further action

NA Groundwater Supply Well Not Sampled No further action

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).

2 The ARNG performed 

this SI at the Central Oregon Unit Training Equipment Site (COUTES) in Redmond, Oregon. 

COUTES 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) (United States Environmental Protection 

Agency [USEPA] 1980), as amended, the National Oil and Hazardous Substances Pollution 

Contingency Plan (Title 40 of the Code of Federal Regulations, Part 300; USEPA 1994), and in 

compliance with United States Department of Army (DA) requirements and guidance for field 

investigations.

1.2 SITE INSPECTION PURPOSE

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

identified two Areas of Interest (AOIs) where PFAS-containing materials may have been used, 

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

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

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

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

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 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

COUTES encompasses 35.5 acres east of Redmond, Oregon. The Facility is located adjacent to 

and east of the Redmond Airport. The nearest metropolitan area is Redmond, Oregon, 2.2 miles 

west of the Facility (Figure 2-1). Parcels surrounding COUTES are undeveloped land on all 

boundaries, with the airport owning the land to the west. COUTES occupies 29.1 acres of land 

administered by the United States Army Corps of Engineers (USACE) and licensed for use by 

the Oregon Military Department (OMD) since 1987. The other 6.4 acres that COUTES occupies 

is owned by the City of Redmond and has been used as a National Guard military facility since 

the lease to OMD began in 1973. Currently, the Facility is used for vehicle maintenance and 

warehouse storage. Historically, there was a firing range on the eastern portion of the Facility 

used for training purposes. The Facility includes a maintenance building, wash rack bay, 

warehouse, and inactive firing range. Directly outside of the Facility boundary are airport 

runways and taxiways to the west. Access to the Facility is controlled (AECOM 2020).

2.2 FACILITY ENVIRONMENTAL SETTING

COUTES is in the Deschutes Columbia Plateau geologic province of Oregon. The Facility 

mostly comprises undeveloped, vegetated land underlain by volcanic lava flow beds. The areas 

of the Facility that are paved include the road to enter/exit the Facility and the areas surrounding 

the buildings in the western installation area and the warehouse and firing range in the eastern 

installation area. The paved areas are limited at the Facility and primarily flat. In both directions, 

from west to east and north to south, elevation across the Facility ranges from approximately 

3,050 to 3,070 feet (ft) above mean sea level (Figure 2-2). Overall, topography at the facility

follows a northwest gradient (AECOM 2020). Runoff from the wash pad appeared to flow to the 

north, but due to the primarily flat nature of the pavement and the drive-through use (north to 

south or south to north) of the wash rack bay, it was inferred that runoff could be tracked to the 

south, and overspray could have affected the ground surface to the west.

2.2.1 Geology

The Facility is in a geologic area characterized as basalt and basaltic andesite of the Pleistocene 

to Holocene ages. This geologic feature occurs primarily along the crest of the Cascade Range, 

which is located to the west of the Facility. These basaltic lava flows are the most widespread 

types of surface rocks in the region, with the oldest basalt lava flows exposed west of the 

Deschutes River, which is located approximately 5 miles west of the Facility. Vents from the 

lava flows are dispersed throughout the region as lava and cinder cones. The lava terrain covers 

the region generally as thin sheets of pahoehoe basalt associated with historic fissure eruptions 

where the surface appears ropy with depressions. These landforms are known as “Lava 

Badlands.” The lava flows were estimated to extend from the land surface to 50 to 100 ft below 

ground surface (bgs). Lava Badlands frequently consist of a lava tube system, indicative of a 

lateral spread of lava. The Redmond Caves is one such lava tube system, located approximately 

4 miles northwest of the Facility (AECOM 2020).
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The Facility is underlain by volcanic deposits of the Quaternary Period, the most recent period of 

the Cenozoic era. These volcanic deposits constitute the second major composite stratigraphic 

unit in the region, which is reported to extend to depths greater than 2,000 ft in some areas. This 

unit consists of lava flows, domes, vent deposits, pyroclastic deposits, and volcanic sediments. 

The volcanic bedrock consists of ash and cinders, whereas the sedimentary deposits consist of 

semi-consolidated sand and gravel eroded from volcanic rocks (AECOM 2020).

Soils beneath the Facility consist primarily of the Deschutes-Stukel complex (designated 35B, 

0 to 8% slope) in the northern and western areas of the installation boundary and Stukel-Rock 

outcrop-Deschutes complex (designated 142B, 0 to 8% slope) south of the installation boundary. 

Both soil series consist of shallow, well-drained soils with moderately high permeability located 

in lava plains that formed in ash. The Deschutes complex is characterized as sandy loam in the 

top 31 inches, followed by basalt at depths below 31 inches. The Stukel complex is characterized 

as sandy and cobbly sandy loam in the top 11 inches, followed by gravelly sandy loam to depths 

of 18 inches bgs, and basalt at 18 inches bgs. Bedrock of the Deschutes series is reported at 20 to 

40 inches bgs, while bedrock of the Stukel series is reported at 10 to 20 inches bgs (AECOM, 

2020).

During the SI, silty sands and gravels were observed as the dominant lithology of the 

unconsolidated material below COUTES. The borings were completed to depths ranging from 

2.1 to 5 feet bgs due to refusal. Weathered basalt was encountered at the bottom of several 

borings, which is consistent with the regional geology of the area. One sample for grain size 

analyses was collected at location AOI01-05 and analyzed via ASTM International (ASTM) 

Standard D-422. The results indicate that the soil samples are comprised primarily of sand

(47.7 percent [%]) and silt (29.4%). These results and observations during the SI fieldwork are 

consistent with the reported depositional environment of the region. 

2.2.2 Hydrogeology

The Facility is on the Deschutes Formation, which is the principal aquifer in the Upper 

Deschutes Basin. With annual precipitation up to 90 inches, the Cascade Range is the principal 

groundwater recharge area for the Upper Deschutes Basin (WRCC, 2020). Groundwater from the 

Cascade Range flows through the permeable volcanic rock toward the east into the Upper 

Deschutes Basin, then discharges to streams or flows through the subsurface of the Deschutes 

Formation, eventually discharging to streams. Groundwater discharge to streams is the principal 

mechanism of groundwater losses in the system because stream elevation is lower than the 

groundwater table. Groundwater discharges to streams occur west of the Facility, surrounding 

the confluence of the Deschutes River (west of Bend, Oregon). The Deschutes River maintains 

substantial flow during regional dry periods. Stream discharge varies by location and seasonal 

precipitation. Regionally, the water table fluctuates in association with recharge. Infiltration of 

precipitation in the region occurs from rainfall, snowmelt, canal and stream leaks, and irrigation 

water. The United States Geological Survey (USGS) estimated annual recharge from infiltration 

of precipitation in the area surrounding the Facility ranges from 0 to 1.5 inches. Recharge 

averages 35 to 40% of the annual precipitation measured throughout the Upper Deschutes Basin 

(AECOM 2020).
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Groundwater flow generally follows the topographic gradient, which is to the northwest. 

Groundwater flow may vary in localized areas where groundwater recharges to surface water or 

near locations of groundwater extraction (e.g., supply wells). Groundwater flow at the Facility 

was not determined during the SI but is inferred to flow to the northwest, based on available

regional information. The upper-most saturated zone is hundreds of feet below ground surface 

and within bedrock (AECOM, 2020). Groundwater sampling during the SI was limited to the 

collection of groundwater from one existing supply well; therefore, synoptic water level 

measurements for determining flow direction were not collected. Perched groundwater was not 

encountered during the SI activities. More information is provided in Section 5.3.

An onsite water supply well is located in the central portion of the Facility, outside the 

northeastern corner of the maintenance building (Well #59860) (Figure 2-3). The well was 

completed in 2013 to a depth of 600 ft bgs, with a screened interval of 517 to 597 ft bgs. Depth 

to groundwater reported on installation drilling records was 341 ft bgs. A well installation log is 

provided in Appendix E. Prior to the use of this well, COUTES obtained drinking water from 

Well #3954, which was located east of the maintenance building and was abandoned in 2018.

The abandoned well was completed in May 1979 to a depth of 425 ft bgs; depth to water 

measured during installation was reported at 390 ft bgs. 

The Oregon Department of Environmental Quality (ODEQ) maintains a well protection program 

to assist public water systems with protecting their sources of drinking water. ODEQ defines 

drinking water source areas based on the location of a supply well and the associated upgradient 

area representing groundwater that will reach the supply well within 10 years. The upgradient 

end (10-year travel time) of one of these source areas for Redmond Water Department Well #2 

extends to within approximately 700 ft of the northwestern boundary of the Facility; Well #2 is 

located more than 2 miles northwest of the COUTES boundary (ODEQ 2017, 2020). 

The nearest USGS monitoring well is located approximately 8 miles east of the Facility (Site 

No. CROO0001954). This well was drilled to 450 ft bgs, and depth to groundwater ranged from 

245 to 315 ft bgs between 1981 and 2018 (AECOM 2020).

Based on USEPA’s Unregulated Contaminant Monitoring Rule 3 data (samples collected 

between 2013 and 2016), no PFAS were detected in a public water system above 70 parts per 

trillion within 20 miles of the Facility, including the cities of Redmond and Bend, which were 

sampled in 2013 and 2014. PFAS analyses performed in 2016 had method detection limits that 

were higher than currently achievable; it is possible that low concentrations of PFAS, if present 

below 2014 detection limits, would be detected if analyzed today (AECOM 2020).

2.2.3 Hydrology

The Facility is in the North Unit Main Canal subwatershed (USGS Hydrologic Unit Code 

[HUC] 12), which is within the Lone Pine Creek-Crooked River (HUC 10) watershed of the 

Lower Crooked subbasin (HUC 8), of the Deschutes Basin (HUC 6). No surface water features 

are located at the Facility. The nearest offsite surface waterbody is the North Unit Main Canal 

less than 0.5 mile east of the Facility (Figure 2-4). The North Unit Main Canal flows toward the 

northeast. The Deschutes River is located approximately 5 miles west of COUTES, flowing to 
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the north, and is a major tributary to the Columbia River (located along the Oregon-Washington 

border). No wetlands are located at the Facility (AECOM 2020).

The Facility is primarily unpaved; paved areas include the roadway, the parking areas 

surrounding the buildings, and the wash rack bay area. Surface stormwater runoff from paved 

areas flows into stormwater catch basins located in the western installation area. Stormwater 

runoff to unpaved areas infiltrates into the soil. Surface water runoff at COUTES would occur 

only during heavy precipitation events when precipitation exceeds the infiltration rate of the soil 

(AECOM 2020).

2.2.4 Climate

Climate in the Deschutes Basin is considered semiarid: moderate with cool, wet winters and 

warm, dry summers. The climate is driven by air masses developing in the Pacific Ocean 

(approximately 150 miles west of COUTES) and moving east over the Cascade Range 

(approximately 35 miles west of COUTES). The Deschutes Basin experiences annual and longterm climate variability with a large differential of temperature extremes over the course of the 

year, but not on any given day. Precipitation decreases significantly east of the Cascade Range 

(WRCC 2020, AECOM 2020).

2.2.5 Current and Future Land Use

The nearest urban area is the City of Redmond, approximately 2 miles west of the Facility. The 

Redmond Airport is immediately adjacent to the west of the Facility. Oregon State Highway 126 

is located less than 0.25 mile north of the Facility. Highway 126 travels east/west from Redmond 

to Prineville to the east and Sisters to the west. Land surrounding the Facility is undeveloped, 

with the airport owning the land to the west. The Facility is zoned as Rural Industrial. Land 

surrounding the Facility is zoned as Exclusive Farm Use Alfalfa (EFUAL – Alfalfa Subzone) to 

the north, east, and south and as Airport Limited to the west. Properties farther west and 

northwest of the Facility are zoned as industrial. Access to the Facility is controlled (AECOM 

2020).

According to the United States Census Bureau, the estimated population of Redmond was 30,011 

in 2017. Based on the population estimates, Redmond’s population increased by nearly 3,800 

between 2010 and 2017. The population of Redmond is expected to increase to 45,724 by 2025. 

Redmond’s urban growth boundary was amended in 2019 to cover over 2,000 acres of additional 

land for residential and industrial land expansion, in addition to the Military Department’s 

National Guard Armory. Redmond’s urban growth boundary is located approximately 2 miles to 

the northwest of the Facility and is not expected to encroach upon the Facility. The Oregon 

Army National Guard’s (ORARNG) preliminary future use plans include adding a new facility 

drinking water well and replacing the current wash rack (AOI 1) with an upgraded wash rack. 

Other long-term plans for the future use of COUTES are unknown. According to the Deschutes 

County Comprehensive Plan, land zoned as Exclusive Farm Use shall be preserved in order to 

protect farmlands. Therefore, future land development of the Facility and adjacent lands is not 

expected to be for purposes other than as currently zoned (AECOM 2020).
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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 (USFWS, 2022):

• Insects: Monarch butterfly, Danaus plexippus (candidate)

• Mammals: Gray wolf, Canis lupus (endangered)

2.3 HISTORY OF PFAS USE

Two potential PFAS release areas were identified at the Facility during the PA (AECOM 2020). 

According to the PA Report, PFAS were potentially released to the ground surface within the 

boundary of COUTES in an area where vehicles, including fire trucks, are washed and in the 

wash rack bay discharge area. A description of each AOI is presented in Section 3. 
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Figure 2-1

Facility Location

COUTES

3

0 2

Miles

Facility Data

Facility Boundary

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

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Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
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Figure 2-2

Facility Topography

!<

Maintenance

Building

AOI 2: Wastewater Discharge Area

AOI 1: Wash Rack Bay

3057

3056

3055

3054

3053

3052

3061

3058

3051

3062

3059

3050

3049

3063

3060

3055

3054

3053

3070

3051

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

Potential PFAS Release

^_ OR

Data Sources: 

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AECOM 2020

NOAA 2021

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Topography

Elevation Contour

(1 ft. interval, NAVD88 datum)

Well Type

!< Facility Water Supply Well

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

Projection:...........NAD 83 UTM 10N
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Figure 2-3

Groundwater Features

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! !

! ! 

!<

Redmond Airport

Warehouse

Inactive Firing Range

North Unit Main Canal

3

0 1,000

Feet

Facility Data

Facility Boundary

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

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Hydrology

Intermittent Creek/Stream

Perennial Creek/Stream

! !

! !

!

Artificial Path

Waterbody

Wetlands

Well Type

!< Facility Water Supply Well

Hydrogeology

Approximate Regional Groundwater Flow Direction

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
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Figure 2-4

Surface Water Features

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! !

! ! 

!<

Redmond Airport

Warehouse

Inactive Firing Range

North Unit

Main Canal

Watershed

North Unit Main Canal

3

0 1,000

Feet

Facility Data

Facility Boundary

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

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Hydrology

Surface Water Flow Direction

Intermittent Creek/Stream

Perennial Creek/Stream

! !

! !

!

Artificial Path

Waterbody

Wetlands

Watershed Boundary Well Type

!< Facility Water Supply Well

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Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
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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, two potential release areas were identified at 

COUTES and grouped into two AOIs identified as: AOI 1 Wash Rack Bay and AOI 2 

Wastewater Discharge Area. The AOIs are shown on Figure 3-1.

3.1 AOI 1 – WASH RACK BAY

AOI 1 consists of an uncovered wash rack bay located at the Facility to the west, south, and east 

of the oil/water separator building and west of the maintenance hangar. According to interviewed 

personnel, Facility equipment and vehicles, including OMD fire trucks, are washed in this area. 

The fire trucks are washed only during the summer months, and hoses are not flushed. According 

to interviewed OMD personnel, the OMD fire trucks have not historically used or currently 

contain AFFF. The duration of the Facility’s use of the wash rack, in addition to the potential 

historical presence of AFFF contained in OMD fire trucks, is not known (AECOM 2020).

3.2 AOI 2 – WASTEWATER DISCHARGE AREA

AOI 2 consists of an area inside the facility boundary where treated wash water (processed 

through the oil/water separator/AOI 1) combined with stormwater has been discharged via 

irrigation under a Water Pollution Control Facility National Pollutant Discharge Elimination 

System permit since 2001 (type GEN17B, Water Quality File No. 111416) (ODEQ 2021). The 

discharge point is a sprinkler head (approximately 7 feet above the ground surface) which is 

located beyond the western side of the Facility’s motor pool fencing, approximately 200 ft to the 

west and downgradient of the wash rack bay. This discharge area is unpaved with a natural 

vegetative cover. The duration of the Facility’s use of the wash rack and discharge to the 

discharge area, in addition to the potential historical presence of AFFF contained in OMD fire 

trucks, is not known (AECOM 2020). 

3.3 ADJACENT SOURCES

One potential off-facility source of PFAS is adjacent to the Facility and is not under the control 

of the ARNG. A description of the off-facility source is presented below and shown on Figure 

3-1.

3.3.1 The Redmond Municipal Airport

The Redmond Municipal Airport is less than 2 miles west of the Facility, with the runway as 

little as 1,800 ft from the center of the Facility. According to the PA, environmental impacts at 

the airport occurred in relation to aircraft rescue and firefighting events. None of the listed 

compounds were PFAS-containing material. The PA did not provide information on AFFF use at 

the airport. The airport is downgradient of the Facility.

Information available online includes the layout of the Redmond Airport; the fire station is 

located just west of the intersection of the runways, approximately 1 mile west of the COUTES 

boundary, and fire training exercises have recently been conducted near the United States Forest 
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Service buildings north of the runways, approximately 0.7-mile northwest of the Facility (AOPA 

2022). An article acquired since the finalization of the PA indicates that “foam” was used for 

firefighting at the airport (The Bulletin 2020); however, the training operations and fire station 

are down- or cross-gradient from the Facility, based on the inferred regional groundwater flow 

direction.
Figure 3-1

Areas of Interest

!<

Maintenance

Building

AOI 2: Wastewater Discharge Area

AOI 1: Wash Rack Bay

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

Potential PFAS Release

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

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Hydrology/Hydrogeology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

General direction of flow through subsurface piping from the 

Wash Rack Bay to the Wastewater Discharge Area

Well Type

!< Facility Water

Supply Well

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Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
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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 3

2020a), 

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 each of the sampled AOIs.

4.1 PROBLEM STATEMENT

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

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

are presented in Section 6.1 of this report.

4.2 INFORMATION INPUTS

Primary information inputs for the SI include the following:

• The PA Report for COUTES (AECOM 2020);

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

accordance with the site-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 (Figure 2-1 

and Figure 2-2). The scope of the SI was bounded vertically by the depth of borings (maximum 

depth of 5 feet bgs). Off-facility sampling was not included in the scope of this SI. If future offfacility sampling is required, the proper stakeholders will be notified, and necessary rights of 

entry will be obtained by ARNG with property owner(s). Temporal boundaries were limited to 

the 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 

3 Wood Environment & Infrastructure Solutions, Inc (“Wood”), EA’s primary subcontractor on the PFAS SI’s was 

acquired by WSP on September 21, 2022. Due to the acquisition, we have changed our name to WSP USA 

Environment & Infrastructure Inc. (“WSP”). No other aspects of our legal entity or capabilities have changed for 

this project. The term Wood has been replaced with WSP where applicable. Documents prepared by Wood are still 

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

4.5 DATA USABILITY ASSESSMENT

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

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

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

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

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

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

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 Addendum (EA/Wood 2021a, 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, Central Oregon Unit Training Equipment 

Site, Oregon, 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, Central Oregon Unit Training Equipment Site, Oregon dated August 

2021 (EA/Wood 2021a)

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

(EA 2020b)

• Final Accident Prevention Plan/Site Safety and Health Plan Addendum for 

COUTES, Oregon, dated April 2021 (EA/Wood 2021b). 

The SI field activities were conducted from 23 to 24 September 2021 and consisted of 

utility clearance, direct-push technology (DPT) boring and soil sample collection, 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 5.7.

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

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

Systems Manual (QSM) Version 5.3 Table B-15 to fulfill the project DQOs:

• 20 soil samples from 10 boring locations;

• One grab groundwater sample from the Facility potable water supply well;

• Five 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, and a Field Change 

Request form is provided in Appendix B4. 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 and performed utility clearance. Details of these activities are presented 

below. 

5.1.1 Technical Project Planning

The USACE TPP Process, Engineer Manual (EM) 200-1-2 (Department of the Army 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 14 July 2021, prior to SI field activities. The 

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

stakeholders for this SI included ARNG, the ORARNG, ODEQ, 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. TPP meetings provided an opportunity to 

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

5.1.2 Utility Clearance

Wood4 contacted the Oregon Utility Notification Center to notify them of intrusive work at the 

Facility. Wood contracted APS, 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 23 September 2021 with input from the Wood field team. General locating services 

and ground-penetrating radar (GPR) were used to complete the clearance. Additionally, Facility 

drawings were reviewed to supplement the private locate results, and representatives from 

Pacific Power and CenturyLink utilities met Wood’s field crew on site to clear utilities at AOI 2. 

The City of Redmond and the Federal Aviation Administration were notified through the public 

utility locate ticket prior to drilling activities and did not reply with any concerns about the 

planned drilling area. The first few feet of each boring were precleared to the extent reasonably 

feasible by Wood’s drilling subcontractor, Steadfast Services, LLC, using a hand auger to verify 

utility clearance in shallow subsurface locations where utilities would typically be encountered.

See Section 5.7 for further details regarding this deviation from the UFP-QAPP Addendum.

4 Work was conducted by Wood Environment & Infrastructure Solutions, Inc., prior to the acquisition by WSP.
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5.1.3 Source Water and PFAS Sampling Equipment Acceptability

PFAS-free water used for decontamination of drilling equipment and equipment blanks was 

provided by Eurofins. Prior to mobilization, the water from Eurofins was certified by the 

laboratory to be PFAS-free by analysis for PFAS by LC/MS/MS compliant with QSM Version 

5.3, Table B-15 (DoD 2019a). The certified water was then bottled and shipped to WSP for use 

as decontamination and equipment blank water during the SI field work.

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 (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 2021). 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 2 ft of each boring. 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 a 3-foot offset for reasons including drill rig access, utility avoidance, and bias 

toward sampling within observed drainage features. The total depth of each boring is shown in 

Table 5-2.

Three discrete soil samples were planned to be collected for chemical analysis from each soil 

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

soil sample was to be collected approximately 1 ft above the perched groundwater table, if 

encountered, and one collected at the mid-point between the surface and the perched

groundwater (not to exceed 15 ft bgs). If refusal was encountered at 6 ft bgs or shallower, only 

two discrete soil samples were planned to be collected per boring: one surface soil sample (0 to 2 

ft bgs) and one sample approximately 1 ft above refusal, assuming perched groundwater was not 

encountered. 

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. 

During the SI, silty sands and gravels were observed as the dominant lithology of the 

unconsolidated material. The borings were completed to depths ranging from 2.1 to 5 feet bgs

due to refusal. Competent rock, observed as weathered basalt, was encountered at the bottom of 

several borings, which is consistent with the regional geology of the area. Neither perched 

groundwater nor saturated soils were encountered in the borings. 
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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 procedures to the 

laboratory and analyzed for PFAS (LC/MS/MS compliant with QSM Version 5.3 Table B-15), 

total organic carbon (TOC) (USEPA Method 9060A), pH (USEPA Method 9045D), and grain 

size (ASTM Standard 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. MS/MSDs were collected at a rate of 5% and analyzed for the same 

parameters as the accompanying samples. In instances when non-dedicated sampling equipment 

was used, such as a hand auger for the shallow soil samples, 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 subsequently abandoned after sampling and surveying in accordance with the 

UFP-QAPP Addendum (EA/Wood 2021a). Boreholes were filled using bentonite chips, 

hydrated, and capped with a concrete plug where concrete was penetrated. Five of the seven 

borings in AOI 1 were installed in locations where the surface was covered with gravel, while 

borings COUTES-AOI01-03 and COUTES-AOI01-05 were installed in areas paved with 

concrete. Borings in AOI 2 were installed in an unpaved area, and surrounding soil was used to 

cover the bentonite fill.

5.3 GROUNDWATER GRAB SAMPLING

The static groundwater level at COUTES is estimated to be approximately 340 to 390 feet bgs

based on measurements documented during installation of the facility drinking water wells. No 

temporary wells were installed at the Facility during the SI field activities as groundwater was 

not encountered in any of the borings. An existing potable supply well is present at COUTES 

and was available for sampling during the SI investigation; however, because the existing 

drinking water well is located cross-gradient to the AOIs, the results from this well are 

considered informational and they may not be reflective of groundwater associated with the 

AOIs. 

Groundwater was collected from the Facility water supply well used for drinking water at the 

Facility in accordance with the UFP-QAPP Addendum. The supply well has a total depth of 

600 ft bgs, a screened interval of 517 to 597 ft bgs, and a previously recorded depth to water of 

341 ft bgs. The groundwater sample was collected from a spigot at the surface in the pumphouse 

of the supply well. The sample was collected in laboratory-supplied PFAS-free HDPE bottles 

and labeled using a PFAS-free marker or pen. The well was purged for approximately 15 

minutes; purged water was discharged to the ground surface outside the well house using a hose 

attached to the spigot at the wellhead. The hose was removed for sample collection. 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) after the grab sample was collected. Samples were packaged 

on ice and transported via FedEx under standard chain-of-custody procedures to the laboratory 
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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).

One water field duplicate was collected and analyzed for the same parameters as the 

accompanying sample. One MS/MSD was collected and analyzed for the same parameters as the 

accompanying sample. One field blank was collected in accordance with the UFP-QAPP 

Addendum (EA/Wood 2021a). A temperature blank was placed in each cooler to ensure that 

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

5.4 SURVEYING

Each boring location was surveyed using a Trimble R12i real-time kinematic Global Navigation 

Satellite System Receiver on the Oregon Real-Time Network. Positions were collected in the 

applicable Universal Transverse Mercator zone projection using the North American Datum of 

1983 (horizontal) and North American Vertical Datum of 1988 (vertical), both measured in 

meters. Survey data were collected on 24 September 2021 and are provided in Appendix B3. 

5.5 INVESTIGATION-DERIVED WASTE

As of the date of this report, the disposal of PFAS investigation-derived waste (IDW) is not 

regulated federally. IDW generated during the SI is considered non-hazardous waste and was 

managed in accordance with the UFP-QAPP Addendum (EA/Wood 2021a). 

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

generated during the SI activities were drummed separately in 55-gallon steel drums approved by 

the United States Department of Transportation. The IDW drums were subsequently stored 

within secondary containment in a dedicated indoor area within the Facility. The IDW was not 

sampled and assumes the characteristics of the associated soil samples collected from that source 

location. The IDW disposal is being managed under a separate contract by EA. Specifics on the 

disposal of solid and liquid IDW will be addressed in an IDW Technical Memorandum.

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.

5.6 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. 

One soil sample was also analyzed for TOC using USEPA Method 9060A, pH by USEPA

Method 9045D, and grain size using ASTM Standard D-422.
Site Inspection Report

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5.7 DEVIATIONS FROM SI UFP-QAPP ADDENDUM

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

field activities. These deviations were discussed among EA, Wood, ARNG, ORARNG, and 

USACE. Deviations from the UFP-QAPP Addendum are noted below:

• After evaluation of drainage patterns in both AOIs during the utility locate site 

visit, the field team determined the proposed boring locations as shown in the 

UFP-QAPP Addendum did not comprehensively cover the area most likely to be 

affected by tracking/drainage from the potential source areas. The field team 

suggested relocating and/or adding boring locations to more comprehensively 

investigate the area most likely to be affected by drainage from the potential 

source areas. Three boring locations were added to AOI 1 (COUTES-AOI01-05, 

COUTES-AOI01-06, and COUTES-AOI01-07). In order to communicate these 

changes, and receive approval and concurrence among WSP, EA, ARNG, 

USACE, and ORARNG, a field change request was submitted to ARNG on 16 

September 2021. 

• The locations of borings at AOI 2 were adjusted based on field observations and 

the location of existing septic system components. In order to communicate these 

changes, and receive approval and concurrence among WSP, EA, ARNG, 

USACE, and ORARNG, a field change request was submitted to ARNG on 16 

September 2021. 

• Hand augering was not performed to a depth of 5 feet, as prescribed in the UFPQAPP Addendum. At all boring locations in AOI 1 and AOI 2, subsurface 

lithology prevented the hand auger bit from penetrating farther than 2 feet beneath 

the surface in all locations. A thorough private utility locate, Facility drawings, 

and field observations provided sufficient evidence to proceed with DPT boring 

activities.

• Borings at all boring locations within AOI 1 and AOI 2 were not advanced to the 

maximum planned boring depth of 13 to 15 ft bgs. Refusal at basalt bedrock was 

encountered at depths ranging between 2.1 and 5 ft bgs. 

In addition, the UFP-QAPP Addendum contained an error regarding the soil extraction holding 

time. The PFAS extraction holding time for soil should have been identified as 28 days, 

consistent with the Programmatic UFP-QAPP (EA 2020a). Holding times for soil (as per the 

programmatic UFP-QAPP) were met.

The actual locations of all borings in AOI 1 and AOI 2 are shown on Figure 5-1. The Field 

Change Request Form is provided in Appendix B4.
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Table 5-1. Site Inspection Samples by Medium

COUTES, Oregon

Site Inspection Report

Sample 

Identification

Sample 

Collection 

Date

Sample 

Depth

(ft bgs)

PFAS(LC/MS/MS compliant with QSM Version 5.3 Table B-15)TOC(USEPA Method 9060A)pH (USEPAMethod 9045D)Grain Size (ASTM D422)

Comments

Soil Samples

COUTES-AOI01-01-1 9/23/21 1.0 X

COUTES-AOI01-01-2 9/23/21 2.0 X

COUTES-AOI01-02-1 9/23/21 1.0 X MS/MSD Collected

COUTES-AOI01-02-3 9/23/21 3.0 X

COUTES-AOI01-03-1 9/23/21 1.0 X Parent Sample of 

COUTES-AOI01-FD01

COUTES-AOI01-FD01 9/23/21 1.0 X FD

COUTES-AOI01-03-3 9/23/21 3.0 X

COUTES-AOI01-04-1 9/23/21 1.0 X Parent Sample of

COUTES-AOI01-FD02

COUTES-AOI01-FD02 9/23/21 1.0 X FD

COUTES-AOI01-04-3 9/23/21 3.0 X

COUTES-AOI01-05-2 9/23/21 2.0 X X X X

COUTES-AOI01-05-4 9/23/21 4.0 X

COUTES-AOI01-06-1 9/23/21 1.0 X

COUTES-AOI01-06-4 9/23/21 4.0 X

COUTES-AOI01-07-1 9/23/21 1.0 X

COUTES-AOI01-07-2 9/23/21 2.0 X

COUTES-AOI02-01-1 9/23/21 1.0 X

COUTES-AOI02-01-2 9/23/21 2.0 X

COUTES-AOI02-02-1 9/23/21 1.0 X

COUTES-AOI02-02-2 9/23/21 2.0 X

COUTES-AOI02-03-1 9/23/21 1.0 X MS/MSD Collected

COUTES-AOI02-03-3 9/23/21 3.0 X Parent Sample of 

COUTES-AOI02-FD01

COUTES-AOI02-FD01 9/23/21 3.0 X FD

Groundwater Samples

COUTES-Well-0921 9/24/21 - X MS/MSD Collected

Parent Sample of COUTES-FD01

Blank Samples

COUTES-FB-01 9/24/21 - X Collected during sampling of 

COUTES-Well-0921

COUTES-EB-01 9/23/21 - X Equipment Blank

Collected from DPT Probe Shoe

Notes:

ASTM = American Society for Testing and Materials MS/MSD = matrix spike/ matrix spike duplicate

bgs = below ground surface QSM = Quality Systems Manual

FD = field duplicate TOC = total organic carbon

LC/MS/MS = Liquid Chromatography Mass Spectrometry USEPA = United States Environmental Protection Agency
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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Table 5-2. Soil Boring Depths and Temporary Well Screen Intervals

COUTES, Oregon

Site Inspection Report

Area of Interest Boring Location

Soil Boring Depth

(ft bgs)

Temporary Well 

Screen Interval

(ft bgs)

1

COUTES-AOI01-01 3.0 -

COUTES-AOI01-02 4.5 -

COUTES-AOI01-03 4.5 -

COUTES-AOI01-04 4.0 -

COUTES-AOI01-05 5.0 -

COUTES-AOI01-06 5.0 -

COUTES-AOI01-07 3.5 -

2

COUTES-AOI02-01 2.1 -

COUTES-AOI02-02 3.0 -

COUTES-AOI02-03 4.0 -

Notes:

Boring depths are the depth at which refusal was reached during drilling.

Abbreviations:

- = not applicable; groundwater not encountered

bgs = below ground surface

ft = feet
Figure 5-1

Site Inspection Sample Locations

!(!(!(

!(

!(

!(

!(

!(

!(

!(

<!

Supply Well Sampling Location

AOI 2: Wastewater Discharge Area

AOI 1: Wash Rack Bay

COUTES-AOI02-01

COUTES-AOI02-03

COUTES-AOI02-02

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06

COUTES-AOI01-07

COUTES-AOI01-03

COUTES-AOI01-02

COUTES-AOI01-01

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

Potential PFAS Release

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 5-1 Site Inspection Sample Locations.mxd - stephane.descombes - 5/1/2023 - 12:31:38 PM

Sample Location

!( Soil Boring Location

<! Facility Water Supply Well

Hydrology/Hydrogeology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

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EA Engineering, Science, and Technology, Inc., PBC 5-10

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Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

EA Engineering, Science, and Technology, Inc., PBC 6-1

6. SITE INSPECTION RESULTS

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

presented in Section 6.1. A discussion of the results for each AOI is provided in Sections 6.3

and 6.4. SLs for relevant compounds, for both soil and groundwater, are presented in Table 6-1. 

Table 6-2 through Table 6-4 present results in soil and 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 to the next phase under CERCLA. The SLs 

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

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

COUTES, Oregon

Site Inspection Report

Analyte2

Residential

(Soil)

(μg/kg)1

0-2 ft bgs

Industrial / Commercial

Composite Worker

(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 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 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.

Abbreviations:

μg/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 
Site Inspection Report

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receptors identified at the Facility: the residential scenario is applied to surface soil results (0 to 

2 feet bgs), and the industrial/commercial worker scenario is applied to shallow subsurface soil 

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

because 15 feet is the anticipated limit of construction activities. 

6.2 SOIL PHYSICOCHEMICAL ANALYSES

To provide basic soil parameter information, one soil sample was 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 in comparison to SLs for AOI 1: Wash Rack 

Bay. The soil results are summarized in Table 6-2 and Table 6-3. Soil results are presented on 

Figure 6-1 through Figure 6-5.

6.3.1 AOI 1 Soil Analytical Results

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

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 and Table 6-3

summarize the soil results for the relevant compounds.

Surface soil (0 to 2 feet bgs) was sampled from boring locations COUTES-AOI01-01 through 

COUTES-AOI01-07. Soil was also sampled from shallow subsurface soil (3 to 4 feet bgs) at 

each boring location in this AOI.

PFOA, PFOS, and/or PFNA were detected in surface soil at concentrations below their 

respective SLs at five out of seven boring locations, at detected concentrations ranging from 0.27

to 0.62 J microgram(s) per kilogram (μg/kg) (estimated) for PFOA, 0.34 J (estimated) to 

2.5 μg/kg for PFOS, and 0.23 to 0.28 J μg/kg (estimated) for PFNA. PFBS and PFHxS were not 

detected in surface soil samples.

PFOA was detected in shallow subsurface soil at a concentration below its SL at one out of five

boring locations with subsurface soil samples collected, at a detected concentration of 
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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0.35 J μg/kg (estimated). PFOS, PFBS, PFHxS, and PFNA were not detected in shallow 

subsurface soil at AOI 1.

6.3.2 Conclusions

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

respective SLs. Based on the lack of exceedances of the SLs, further evaluation at AOI 1 is not

warranted.

6.4 AOI 2

This section presents the analytical results for soil in comparison to SLs for AOI 2: Wastewater 

Discharge Area. The soil results are summarized in Table 6-2 and Table 6-3. Soil results are 

presented on Figure 6-1 through Figure 6-5.

6.4.1 AOI 2 Soil Analytical Results

Soil samples were collected from three boring locations associated with AOI 2 during the SI. 

Figure 6-1 through Figure 6-5 present the ranges of detections in soil. Table 6-2 and Table 6-3

summarize the soil results.

Surface soil (0 to 2 feet bgs) was sampled from boring locations COUTES-AOI02-01 through 

COUTES-AOI02-03. Soil was also sampled from shallow subsurface soil (3 feet bgs) at one 

boring location COUTES-AOI02-03. 

PFOA and PFOS were detected in surface soil at concentrations below their respective SLs at all 

three boring locations, at detected concentrations ranging from 0.27 to 0.52 μg/kg (estimated) for 

PFOA, and 0.39 (estimated) and 1.0 μg/kg for PFOS. PFBS, PFHxS, and PFNA were not 

detected in surface soil at AOI 2.

PFOA and PFOS were detected in shallow subsurface soil at concentrations below their

respective SLs at boring COUTES-AOI02-03, at concentrations of 0.23 J μg/kg and 0.25 J μg/kg

(estimated), respectively. PFOA and PFOS were not detected in the field duplicate sample at this 

same location. PFBS, PFHxS, and PFNA were not detected in shallow subsurface soil at AOI 2.

6.4.2 Conclusions

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

Based on the lack of exceedances of the SLs, further evaluation at AOI 2 is not warranted.

6.5 POTABLE SUPPLY WELL

The UFP-QAPP Addendum stated that if perched groundwater was encountered during boring 

installation, it would be sampled; however, perched groundwater was not encountered in the 

borings completed for the SI. An existing potable water supply well at the Facility was sampled 

in accordance with the UFP-QAPP Addendum. 
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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The static groundwater level at COUTES is estimated to be approximately 340 to 390 feet bgs 

based on measurements documented during installation of the facility drinking water wells. An 

existing potable supply well is present at COUTES and was available for sampling during the SI 

investigation; however, because the existing drinking water well is located cross-gradient to the 

AOIs, the results from this well are considered informational and they may not be reflective of 

groundwater associated with the AOIs.

6.5.1 Groundwater Analytical Results 

Table 6-4 and Figure 6-6 and Figure 6-7 present the sampling location and results of the 

groundwater sample. 

The water supply well is located northeast and cross-gradient of the AOIs (Figure 3-1). PFAS 

was not detected in groundwater and, therefore, the relevant compounds did not exceed the SLs.

6.5.2 Conclusions

Based on the results of the SI, the groundwater sample collected did not exceed the SLs for the 

relevant compounds. Based on the lack of exceedances of the SLs, further evaluation of 

groundwater at the Facility is not warranted. 
Table 6-2

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

COUTES, Oregon

Analyte Screening Level a Result LOD LOQ Qual Result LOD LOQ Qual Result LO

 Soil, PFAS (LC/MS/MS) (μg/kg) compliant with QSM Version 5.3 Table B-15Perfluorooctanoic acid (PFOA) 19 0.27 0.40 0.60 J 0.52 0.44 0.65 J 0.31 0.3

Perfluorooctanesulfonic acid (PFOS) 13 < 0.40 0.60 U < 0.44 0.65 U 0.34 0.3

Perfluorobutanesulfonic acid (PFBS) 1,900 < 1.6 2.0 U < 1.7 2.2 U < 1.Perfluorohexanesulfonic acid (PFHxS) 130 < 0.40 0.60 U < 0.44 0.65 U < 0.3Perfluorononanoic acid (PFNA) 19 < 0.40 0.60 U < 0.44 0.65 U 0.26 0.3

 = Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersJ = Estimated concentrationU = The analyte was not detected at a level greater than or equal to the adjusted DL.Chemical Abbreviations PFAS per- and polyfluoroalkyl substancesPFBS perfluorobutanesulfonic acid PFHxS perfluorohexanesulfonic acid PFNA perfluorononanoic acid PFOA perfluorooctanoic acid PFOS perfluorooctanesulfonic acidAcronyms and Abbreviations< analyte not detected above the LODAOI Area of InterestDL detection limitft feetHQ hazard quotientLC/MS/MS liquid chromatography with tandem mass spectrometryLOD limit of detectionOSD Office of the Secretary of DefenseQual interpreted qualifierUSEPA United States Environmental Protection Agencyμg/kg microgram(s) per kilogram

Location ID COUTES-AOI01-01 COUTES-AOI01-01 COUT

Area of Interest 

AOI 1

Sample Name COUTES-AOI01-01-1 COUTES-AOI01-01-2 COUT

Parent Sample ID

Depth 1 ft 2 ft 

Sample Date 9/23/2021 9/23/2021 

a. Assistant Secretary of Defense. July 2022. Risk-Based Screening Levels Calculated forPFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA's Regional

Screening Level Calculator. HQ=0.1. May 2022. Soil Screening levels based onresidential scenario for direct ingestion of contaminated soil.

Grey Fill

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Table 6-2

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

COUTES, Oregon

Analyte Screening Level a

 Soil, PFAS (LC/MS/MS) (μg/kg) compliant with QSM Version 5.3 Table B-15Perfluorooctanoic acid (PFOA) 19

Perfluorooctanesulfonic acid (PFOS) 13Perfluorobutanesulfonic acid (PFBS) 1,900Perfluorohexanesulfonic acid (PFHxS) 130Perfluorononanoic acid (PFNA) 19

 = Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersJ = Estimated concentrationU = The analyte was not detected at a level greater than or equal to the adjusted DL.Chemical Abbreviations PFAS per- and polyfluoroalkyl substancesPFBS perfluorobutanesulfonic acid PFHxS perfluorohexanesulfonic acid PFNA perfluorononanoic acid PFOA perfluorooctanoic acid PFOS perfluorooctanesulfonic acidAcronyms and Abbreviations< analyte not detected above the LODAOI Area of InterestDL detection limitft feetHQ hazard quotientLC/MS/MS liquid chromatography with tandem mass spectrometryLOD limit of detectionOSD Office of the Secretary of DefenseQual interpreted qualifierUSEPA United States Environmental Protection Agencyμg/kg microgram(s) per kilogram

Location ID

Area of Interest 

Sample Name

Parent Sample ID

Depth

Sample Date

a. Assistant Secretary of Defense. July 2022. Risk-Based Screening Levels Calculated forPFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA's Regional

Screening Level Calculator. HQ=0.1. May 2022. Soil Screening levels based onresidential scenario for direct ingestion of contaminated soil.

Grey Fill

Result LOD LOQ Qual Result LOD LOQ Qual Result LO

< 0.44 0.65 U 0.62 0.43 0.65 J 0.47 0.4< 0.44 0.65 U 2.5 0.43 0.65 1.8 0.4

< 1.7 2.2 U < 1.7 2.2 U < 1.< 0.44 0.65 U < 0.43 0.65 U < 0.4< 0.44 0.65 U 0.23 0.43 0.65 J < 0.4

COUTES-AOI01-03

AOI 1

COUTES-AOI01-04 COUT

COUTES-AOI01-FD01 COUTES-AOI01-04-1

COUTES-AOI01-03-1

COUTE

COUT

1 ft 1 ft 

9/23/2021 9/23/2021

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Table 6-2

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

COUTES, Oregon

Analyte Screening Level a

 Soil, PFAS (LC/MS/MS) (μg/kg) compliant with QSM Version 5.3 Table B-15Perfluorooctanoic acid (PFOA) 19

Perfluorooctanesulfonic acid (PFOS) 13Perfluorobutanesulfonic acid (PFBS) 1,900Perfluorohexanesulfonic acid (PFHxS) 130Perfluorononanoic acid (PFNA) 19

 = Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersJ = Estimated concentrationU = The analyte was not detected at a level greater than or equal to the adjusted DL.Chemical Abbreviations PFAS per- and polyfluoroalkyl substancesPFBS perfluorobutanesulfonic acid PFHxS perfluorohexanesulfonic acid PFNA perfluorononanoic acid PFOA perfluorooctanoic acid PFOS perfluorooctanesulfonic acidAcronyms and Abbreviations< analyte not detected above the LODAOI Area of InterestDL detection limitft feetHQ hazard quotientLC/MS/MS liquid chromatography with tandem mass spectrometryLOD limit of detectionOSD Office of the Secretary of DefenseQual interpreted qualifierUSEPA United States Environmental Protection Agencyμg/kg microgram(s) per kilogram

Location ID

Area of Interest 

Sample Name

Parent Sample ID

Depth

Sample Date

a. Assistant Secretary of Defense. July 2022. Risk-Based Screening Levels Calculated forPFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA's Regional

Screening Level Calculator. HQ=0.1. May 2022. Soil Screening levels based onresidential scenario for direct ingestion of contaminated soil.

Grey Fill

Result LOD LOQ Qual Result LOD LOQ Qual Result LO

0.40 0.39 0.59 J < 0.40 0.60 U < 0.40.46 0.39 0.59 J < 0.40 0.60 U < 0.4

< 1.6 2.0 U < 1.6 2.0 U < 1.8 < 0.39 0.59 U < 0.40 0.60 U < 0.4< 0.39 0.59 U < 0.40 0.60 U < 0.4

AOI 1 

COUTES-AOI01-06 COUTES-AOI01-07 COUT

COUTES-AOI01-06-1 COUTES-AOI01-07-1 COUTE

1 ft 1 ft 

9/23/2021 9/23/2021 9

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Table 6-2

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

COUTES, Oregon

Analyte Screening Level a

 Soil, PFAS (LC/MS/MS) (μg/kg) compliant with QSM Version 5.3 Table B-15Perfluorooctanoic acid (PFOA) 19

Perfluorooctanesulfonic acid (PFOS) 13Perfluorobutanesulfonic acid (PFBS) 1,900Perfluorohexanesulfonic acid (PFHxS) 130Perfluorononanoic acid (PFNA) 19

 = Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersJ = Estimated concentrationU = The analyte was not detected at a level greater than or equal to the adjusted DL.Chemical Abbreviations PFAS per- and polyfluoroalkyl substancesPFBS perfluorobutanesulfonic acid PFHxS perfluorohexanesulfonic acid PFNA perfluorononanoic acid PFOA perfluorooctanoic acid PFOS perfluorooctanesulfonic acidAcronyms and Abbreviations< analyte not detected above the LODAOI Area of InterestDL detection limitft feetHQ hazard quotientLC/MS/MS liquid chromatography with tandem mass spectrometryLOD limit of detectionOSD Office of the Secretary of DefenseQual interpreted qualifierUSEPA United States Environmental Protection Agencyμg/kg microgram(s) per kilogram

Location ID

Area of Interest 

Sample Name

Parent Sample ID

Depth

Sample Date

a. Assistant Secretary of Defense. July 2022. Risk-Based Screening Levels Calculated forPFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soil using USEPA's Regional

Screening Level Calculator. HQ=0.1. May 2022. Soil Screening levels based onresidential scenario for direct ingestion of contaminated soil.

Grey Fill

Result LOD LOQ Qual Result LOD LOQ Qual Result LO

0.42 0.48 0.71 J 0.52 0.48 0.72 J 0.27 0.40.99 0.48 0.71 0.54 0.48 0.72 J 0.59 0.4

< 1.9 2.4 U < 1.9 2.4 U < 1.< 0.48 0.71 U < 0.48 0.72 U < 0.4< 0.48 0.71 U < 0.48 0.72 U < 0.4

AOI 2

COUTES-AOI02-01 COUTES-AOI02-02 COUT

COUTES-AOI02-01-2 COUTES-AOI02-02-1 COUT

2 ft 1 ft 

9/23/2021 9/23/2021 

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Table 6-3

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

COUTES, Oregon

Analyte Screening Level a Result LOD LOQ Qual Result LOD LOQ Qual Result LOD 

 Soil, PFAS (LC/MS/MS) (μg/kg) compliant with QSM Version 5.3 Table B-15

Perfluorooctanoic acid (PFOA) 250 < 0.41 0.62 U < 0.43 0.64 U 0.35 0.44 

Perfluorooctanesulfonic acid (PFOS) 160 < 0.41 0.62 U < 0.43 0.64 U < 0.44 

Perfluorobutanesulfonic acid (PFBS) 25,000 < 1.7 2.1 U < 1.7 2.1 U < 1.7 Perfluorohexanesulfonic acid (PFHxS) 1,600 < 0.41 0.62 U < 0.43 0.64 U < 0.44 Perfluorononanoic acid (PFNA) 250 < 0.41 0.62 U < 0.43 0.64 U < 0.44 

 = Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersJ = Estimated concentrationU = The analyte was not detected at a level greater than or equal to the adjusted DL.Chemical Abbreviations PFAS per- and polyfluoroalkyl substancesPFBS perfluorobutanesulfonic acid PFHxS perfluorohexanesulfonic acid PFNA perfluorononanoic acid PFOA perfluorooctanoic acid PFOS perfluorooctanesulfonic acidAcronyms and Abbreviations< analyte not detected above the LODAOI Area of InterestDL detection limitft feetHQ hazard quotientLC/MS/MS liquid chromatography with tandem mass spectrometryLOD limit of detectionOSD Office of the Secretary of DefenseQual interpreted qualifierUSEPA United States Environmental Protection Agencyμg/kg microgram(s) per kilograma. Assistant Secretary of Defense. July 2022. Risk-Based Screening LevelsCalculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soilusing USEPA's Regional Screening Level Calculator. HQ=0.1. May 2022. SoilScreening levels based on industrial/commercial composite worker scenario forincidental ingestion of contaminated soil.

Location ID COUTES-AOI01-02

Area of Interest 

COUTES-AOI01-03

AOI 1

COUTES-A

Sample Name COUTES-AOI01-02-3 COUTES-AOI01-03-3 

Parent Sample ID

COUTES-A

Depth 3 ft 3 ft 3 f

Sample Date 9/23/2021 9/23/2021 9/23/2

Grey Fill

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Table 6-3

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

COUTES, Oregon

Analyte Screening Level a

 Soil, PFAS (LC/MS/MS) (μg/kg) compliant with QSM Version 5.3 Table B-15

Perfluorooctanoic acid (PFOA) 250

Perfluorooctanesulfonic acid (PFOS) 160

Perfluorobutanesulfonic acid (PFBS) 25,000Perfluorohexanesulfonic acid (PFHxS) 1,600Perfluorononanoic acid (PFNA) 250

 = Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersJ = Estimated concentration

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

Chemical Abbreviations PFAS per- and polyfluoroalkyl substancesPFBS perfluorobutanesulfonic acid PFHxS perfluorohexanesulfonic acid PFNA perfluorononanoic acid PFOA perfluorooctanoic acid PFOS perfluorooctanesulfonic acidAcronyms and Abbreviations< analyte not detected above the LODAOI Area of InterestDL detection limitft feetHQ hazard quotientLC/MS/MS liquid chromatography with tandem mass spectrometryLOD limit of detectionOSD Office of the Secretary of DefenseQual interpreted qualifierUSEPA United States Environmental Protection Agencyμg/kg microgram(s) per kilograma. Assistant Secretary of Defense. July 2022. Risk-Based Screening LevelsCalculated for PFOA, PFOS, PFBS, PFHxS, and PFNA in Groundwater or Soilusing USEPA's Regional Screening Level Calculator. HQ=0.1. May 2022. SoilScreening levels based on industrial/commercial composite worker scenario forincidental ingestion of contaminated soil.

Location ID

Area of Interest 

Sample Name

Parent Sample ID

Depth

Sample Date

Grey Fill

Result LOD LOQ Qual Result LOD LOQ Qual Result LOD 

< 0.45 0.67 U 0.23 0.46 0.68 J < 0.48 < 0.45 0.67 U 0.25 0.46 0.68 J < 0.48 

< 1.8 2.2 U < 1.8 2.3 U < 1.9 < 0.45 0.67 U < 0.46 0.68 U < 0.48 < 0.45 0.67 U < 0.46 0.68 U < 0.48 

AOI 1 AOI 2

COUTES-AOI02-03 COUTES-

COUTES-AOI01-06-4

COUTES-AOI01-06

4 ft

COUTES-AOI02-03-3 COUTES-A

9/23/2021 9/23/

COUTES-A

3 ft 3 

9/23/2021

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Table 6-4

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

COUTES, Oregon

Analyte Screening Level 1 Result LOD LOQ Qual Result LOD LOQ Qual

 Water, PFAS (LC/MS/MS) (ng/L)Perfluorooctanoic acid (PFOA) 6 < 0.89 1.8 U < 0.86 1.7 U

Perfluorooctanesulfonic acid (PFOS) 4 < 0.89 1.8 U < 0.86 1.7 U

Perfluorobutanesulfonic acid (PFBS) 601 < 0.89 1.8 U < 0.86 1.7 UPerfluorohexanesulfonic acid (PFHxS) 39 < 0.89 1.8 U < 0.86 1.7 UPerfluorononanoic acid (PFNA) 6 < 0.89 1.8 U < 0.86 1.7 U

Grey Fill Detected concentration exceeded OSD Screening Levels

References

Interpreted QualifiersU = The analyte was not detected at a level greater than or equal to the adjusted DL.Chemical Abbreviations Acronyms and AbbreviationsPFAS per- and polyfluoroalkyl substances < analyte not detected above the LODPFBS perfluorobutanesulfonic acid DL detection limitPFHxS perfluorohexanesulfonic acid HQ hazard quotientPFNA perfluorononanoic acid LOD limit of detection

PFOA perfluorooctanoic acid OSD Office of the Secretary of Defense

PFOS perfluorooctanesulfonic acid Qual interpreted qualifier

USEPA United States Environmental Protection Agencyng/L nanograms per liter

(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 levels based on residential scenario for directingestion of groundwater.

COUTES-WELL

COUTES-FD01

COUTES-WELL-0921

9/24/2021

Location ID

Sample Name

Parent Sample ID

Sample Date

COUTES-WELL

COUTES-WELL-0921

9/24/2021

Site Inspection Report Central Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

EA Engineering, Science, and Technology, Inc., PBC 6-12

This page intentionally left blank
!(

!(

!(

!( !(

!( COUTES-AOI02-03

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06 COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

PFOS Results (ng/g)

!( ND

!( >ND - 13

!( >13 - 160

!( >160 - 1,600

!( >1,600

Figure 6-1

PFOS Detections in Soil

!( !( !(

!(

!(

!(

!(

!(

!(

!(

COUTES-AOI02-01

COUTES-AOI02-03

COUTES-AOI02-02

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06

COUTES-AOI01-07

COUTES-AOI01-01

COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-1 PFOS Detections in Soil.mxd - stephane.descombes - 5/1/2023 - 12:43:06 PM

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

Shallow (0' - 2')

PFOS Results (ng/g)

!( ND

!( >ND - 13

!( >13 - 160

!( >160 - 1,600

!( >1,600

Intermediate (2' - 5')

Note:

ND = Not Detected

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

EA Engineering, Science, and Technology, Inc., PBC 6-14

This page intentionally left blank
!(

!(

!(

!( !(

!( COUTES-AOI02-03

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06 COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

PFOA Results (ng/g)

!( ND

!( >ND - 19

!( >19 - 250

!( >250 - 2,500

!( >2,500

Figure 6-2

PFOA Detections in Soil

!( !( !(

!(

!(

!(

!(

!(

!(

!(

COUTES-AOI02-01

COUTES-AOI02-03

COUTES-AOI02-02

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06

COUTES-AOI01-07

COUTES-AOI01-01

COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-2 PFOA Detections in Soil.mxd - stephane.descombes - 5/1/2023 - 12:33:56 PM

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

PFOA Results (ng/g)

!( ND

!( >ND - 19

!( >19 - 250

!( >250 - 2,500

!( >2,500

Note:

ND = Not Detected

Shallow (0' - 2') Intermediate (2' - 5')

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

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

This page intentionally left blank
!(

!(

!(

!( !(

!( COUTES-AOI02-03

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06 COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

PFBS Results (ng/g)

!( ND

!( >ND - 10

!( >10 - 1,900

!( >1,900 - 25,000

!( >25,000

Figure 6-3

PFBS Detections in Soil

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

COUTES-AOI02-01

COUTES-AOI02-03

COUTES-AOI02-02

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06

COUTES-AOI01-07

COUTES-AOI01-01

COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-3 PFBS Detections in Soil.mxd - stephane.descombes - 5/1/2023 - 12:33:33 PM

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

PFBS Results (ng/g)

!( ND

!( >ND - 10

!( >10 - 1,900

!( >1,900 - 25,000

!( >25,000

Note:

ND = Not Detected

Shallow (0' - 2') Intermediate (2' - 5')

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

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

This page intentionally left blank
!(

!(

!(

!( !(

!( COUTES-AOI02-03

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06 COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

PFHxS Results (ng/g)

!( >ND

!( >ND - 10

!( >10 - 130

!( >130 - 1,600

!( >1,600

Figure 6-4

PFHxS Detections in Soil

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

COUTES-AOI02-01

COUTES-AOI02-03

COUTES-AOI02-02

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06

COUTES-AOI01-07

COUTES-AOI01-01

COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-4 PFHxS Detections in Soil.mxd - stephane.descombes - 5/1/2023 - 12:33:12 PM

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N

PFHxS Results (ng/g)

!( >ND

!( >ND - 10

!( >10 - 130

!( >130 - 1,600

!( >1,600

Note:

ND = Not Detected

Shallow (0' - 2') Intermediate (2' - 5')
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

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

This page intentionally left blank
!(

!(

!(

!( !(

!( COUTES-AOI02-03

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06 COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

PFNA Results (ng/g)

!( ND

!( >ND - 19

!( >19 - 250

!( >250 - 2,500

!( >2,500

Figure 6-5

PFNA Detections in Soil

!(

!( !(

!(

!(

!(

!(

!(

!(

!(

COUTES-AOI02-01

COUTES-AOI02-03

COUTES-AOI02-02

COUTES-AOI01-04

COUTES-AOI01-05

COUTES-AOI01-06

COUTES-AOI01-07

COUTES-AOI01-01

COUTES-AOI01-02

COUTES-AOI01-03

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-5 PFNA Detections in Soil.mxd - stephane.descombes - 5/1/2023 - 12:32:41 PM

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

PFNA Results (ng/g)

!( ND

!( >ND - 19

!( >19 - 250

!( >250 - 2,500

!( >2,500

Note:

ND = Not Detected

Shallow (0' - 2') Intermediate (2' - 5')

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

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

This page intentionally left blank
Figure 6-6

PFOS, PFOA, and PFBS Detections in Groundwater

!(

Supply Well Sampling Location

3

0 150

Feet

Facility Data

Facility Boundary

Area of Interest

OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-6 PFOS-PFOA-PFBS Detections in Groundwater.mxd - stephane.descombes - 5/1/2023 - 12:32:15 PM

PFBS

PFBS Results (ng/L)

!( ND

!( >ND - 100

!( >100 - 600

!!( >600 - 2,000

!!( >2,000

!(

Supply Well Sampling Location

3

0 150

Feet

PFOS

PFOS Results (ng/L)

!( ND

!( >ND - 4

!!( >4 - 40

!!( >40 - 70

!!( >70

!(

Supply Well Sampling Location

3

0 150

Feet

PFOA

PFOA Results (ng/L)

!( ND

!( >ND - 6

!!( >6 - 40

!!( >40 - 70

!!( >70

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon ^_

Note:

ND = Not Detected

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

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

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

This page intentionally left blank
!(

Supply Well Sampling Location

3

0 100

Feet

PFNA Results (ng/L)

!( ND

!( >ND - 6

!!( >6 - 100

!!( >100 - 1,000

!!( >1,000

Figure 6-7

PFHxS & PFNA Detections in Groundwater

!(

Supply Well Sampling Location

3

0 100

Feet

Facility Data

Facility Boundary

Area of Interest

^_ OR

Data Sources: 

ESRI 2020

AECOM 2020

Hydrology

Surface Water Flow Direction

Approximate Regional Groundwater Flow Direction

K:\NGB Contract\ARNG PFAS SI\COUTES Redmond\13.0 GIS\_SI\Figure 6-7 PFHxS & PFNA Detections in Groundwater.mxd - stephane.descombes - 5/1/2023 - 12:31:14 PM

Army National Guard Site Inspections

Site Inspection Report

COUTES, Oregon

PFHxS

PFHxS Results (ng/L)

!( ND

!( >ND - 39

!!( >39 - 100

!!( >100 - 1,000

!!( >1,000

PFNA

Note:

ND = Not Detected

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

Date:.................................May 2023

Prepared By:............................WSP

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

Projection:...........NAD 83 UTM 10N
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

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

This page intentionally left blank
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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

7. EXPOSURE PATHWAYS

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

on Figure 7-1 through Figure 7-2. Please note that while the CSM discussion assists in 

determining if a receptor may be impacted, the decision to move from SI to remedial 

investigation (RI) or interim action is determined based upon exceedances of the SLs for the 

relevant compounds and whether the release is more than likely attributable to the DoD. A CSM 

presents the current understanding of the 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 USEPA guidance for risk screening (USEPA 2001). 

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

construction workers. 

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. 
Site Inspection Report

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7.1.1 AOI 1

AOI 1 is the Wash Rack Bay, and there are no known or documented releases of PFAS at AOI 1. 

The Wash Rack Bay and area to the east are paved with concrete, located outdoors, and 

uncovered. The surface area surrounding the Wash Rack Bay is covered with gravel. The Wash 

Rack Bay pavement slopes into two catch basins within the paved area. PFOA, PFOS, and PFNA 

were detected in soil at concentrations below SLs at boring locations completed at AOI 1. Site 

workers and construction workers could contact relevant compounds in surface soil via 

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

site workers and construction workers are potentially complete. PFOA was detected in shallow 

subsurface soil at a concentration below the SL at AOI 1. Construction workers could contact 

relevant compounds in subsurface soil during ground-disturbing activities via ingestion and 

inhalation of dust; therefore, the subsurface soil exposure pathway for construction workers is

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

7.1.2 AOI 2

AOI 2 is the Wastewater Discharge Area associated with the wash rack bay (AOI 1). AOI 2 is 

located west of the Facility’s operational area, west of the Facility fencing. There are no known 

or documented releases of PFAS at AOI 2. This discharge area is unpaved with a natural 

vegetative cover. Wastewater from the Wash Rack Bay, which consists of treated wash water

and stormwater, is discharged via irrigation sprinkler into AOI 2. PFOA and PFOS were detected 

in surface soil at concentrations below SLs at boring locations at AOI 2. Site workers and 

construction workers could contact relevant compounds in surface soil via inhalation of dust or 

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

construction workers are potentially complete. PFOA and PFOS were detected in shallow 

subsurface soil at AOI 2 at concentrations below their respective SLs. Construction workers 

could contact relevant compounds in subsurface soil during ground-disturbing activities via 

incidental ingestion and inhalation of dust; therefore, the subsurface soil exposure pathway for 

construction workers is potentially complete. The CSM for AOI 2 is presented on Figure 7-2.

7.2 GROUNDWATER EXPOSURE PATHWAY

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

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

criteria. 

Perched groundwater was not encountered during the SI investigation. Groundwater was 

evaluated based on the sample collected from the Facility’s potable supply well.
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7.2.1 Potable Supply Well

An existing potable supply well is present at COUTES and was available for sampling during the 

SI investigation. The Facility water supply well was sampled for evaluation of PFAS in deep 

groundwater. Because the existing drinking water well is located cross-gradient to the AOIs, the 

results from this well are considered informational and they may not be reflective of groundwater 

associated with the AOIs. Based on the results of this sample, PFAS is not present at detectable

concentrations in deep groundwater. The exposure pathway is incomplete for groundwater at 

COUTES. The CSMs are presented on Figure 7-1 and Figure 7-2. 
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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RECEPTOR

Human Receptors

Current/Future

Site 

Worker

Construction 

Worker Resident1 

Construction 

Worker

Resident1 

Leaching/Infiltration

SOURCE

Source Release Mechanism Media

PATHWAY

Transport

and Migration Media Exposure Routes

NOTES1. The resident users refer to off-site

receptors.

2. Dermal contact exposure pathway is 

incomplete for PFAS.

Figure 7-1

Conceptual Site Mo

COUTES

PFAS in 

Subsurface 

Soil

Precipitation

/ Run-Off

Human 

Activities

Wash Rack Bay;

Wastewater

Discharge Area

AOI 1AOI 2

Surface 

Soil

at AOI

Inhalation of

Dust

Ingestion

Subsurface 

Soil Ingestion

Groundwater

PFAS in 

Surface 

Soil

Ingestion

LEGEND

Flow-Chart Continues Incomplete PathwayPotentially Complete PathwayPotentially Complete Pathway with Exceedance of SLGroundwater analyzed was cross-gradient of AOIs with no detections

Site 

Worker

Airborne 

Soil 

Particulate

Site Inspection ReportCentral Oregon Unit Training Equipment Site, Oregon EA Engineering, Science, and Technology, Inc., PBC 
Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL 

EA Engineering, Science, and Technology, Inc., PBC 7-6

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Site Inspection Report

Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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 23 to 24 September 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 5.7. 

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. 

• 20 soil grab samples from 10 boring locations

• One grab groundwater sample from the potable supply well

• 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 multimedia 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, no further evaluation under CERCLA in the form of a RI is 

warranted for AOI 1 or AOI 2 at this time. Based on the CSMs developed and revised in light of

the SI findings, there is potential for exposure to receptors from AOI 1 and AOI 2 from sources 

on the Facility resulting from historical DoD activities. 

Relevant compound concentrations in media collected during the SI were compared against the 

project SLs in soil and groundwater, as listed in Table 6-1. A summary of the results of the SI 

data relative to SLs is as follows:

At AOI 1:

PFOA, PFOS, and PFNA were detected in soil at AOI 1 below SLs. PFBS and PFHxS were not 

detected in soil at AOI 1. 
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Based on the results of the SI, no further evaluation of AOI 1 is warranted. 

At AOI 2:

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

detected in soil at AOI 2. 

Based on the results of the SI, no further evaluation of AOI 2 is warranted. 

Groundwater:

PFOA, PFOS, PFBS, PFNA, and PFHxS were not detected in the groundwater sample collected 

from the Facility potable water supply well.

Based on the results of the SI, no further evaluation of groundwater at the Facility is warranted.

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 military 

specification (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

COUTES, Oregon 

Site Inspection Report

AOI Potential Release Area

Soil – 

Source Area

Groundwater – 

Source Area

Future Action

1 Wash Rack Bay Not Sampled No further action

2 Wastewater Discharge Area Not Sampled No further action

NA Groundwater Supply Well Not Sampled No further action

Legend:

 = Detected; exceedance of screening levels

 = Detected; no exceedance of screening levels

 = Not detected
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EA Engineering, Science, and Technology, Inc., PBC 9-2

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Central Oregon Unit Training Equipment Site, Oregon Version: FINAL

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