FINAL

Site Inspection Report 

Rickenbacker Army Enclave

Columbus, Ohio

Perfluorooctanesulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

December 2022

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
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Table of Contents

Executive Summary ................................................................................................................ ES-1

1. Introduction .................................................................................................................... 1-1

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

1.2 SI Purpose .............................................................................................................. 1-1

2. Facility Background........................................................................................................ 2-1

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

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

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

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

2.2.3 Hydrology ..................................................................................................... 2-3

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

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

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

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

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

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

3.1.1 C26 Hangar .................................................................................................. 3-1

3.2 AOI 2....................................................................................................................... 3-1

3.2.1 Drainage Ditch.............................................................................................. 3-1

3.3 AOI 3....................................................................................................................... 3-2

3.3.1 Helicopter Ramp Area .................................................................................. 3-2

3.4 Facility Boundary .................................................................................................... 3-2

3.4.1 Off-Facility/ Upgradient Potential Release Area ........................................... 3-2

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

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

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

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

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

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

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

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

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

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

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

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

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

5. Site Inspection Activities................................................................................................. 5-1

5.1 Pre-Investigation Activities...................................................................................... 5-1

5.1.1 Technical Project Planning ........................................................................... 5-1

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

5.1.3 Source Water and PFAS Sampling Equipment Acceptability ....................... 5-2

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

5.3 Temporary Well Installation and Groundwater Grab Sampling ............................... 5-3

5.4 Synoptic Water Level Measurements ..................................................................... 5-4
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5.5 Surveying................................................................................................................5-4

5.6 Investigation-Derived Waste ...................................................................................5-4

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

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

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

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

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

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

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

6.3.2 AOI 1 Conclusions........................................................................................6-2

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

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

6.4.2 AOI 2 Groundwater Analytical Results .........................................................6-3

6.4.3 AOI 2 Conclusions........................................................................................6-3

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

6.5.1 AOI 3 Soil Analytical Results ........................................................................6-3

6.5.2 AOI 3 Groundwater Analytical Results .........................................................6-4

6.5.3 AOI 3 Conclusions........................................................................................6-4

6.6 Facility Boundary ....................................................................................................6-4

6.6.1 Facility Boundary Soil Analytical Results......................................................6-4

6.6.2 Facility Boundary Groundwater Analytical Results .......................................6-5

6.6.3 Facility Boundary Conclusions .....................................................................6-5

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

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

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

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

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

7.1.4 Facility Boundary ..........................................................................................7-2

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

7.2.1 AOI 2 ............................................................................................................7-3

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

7.2.3 Facility Boundary ..........................................................................................7-3

7.3 Surface Water and Sediment Exposure Pathway (Adjacent Sources and AOI 

2) ........................................................................................................................7-4

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

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

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

8.3 Outcome .................................................................................................................8-3

9. References.....................................................................................................................9-1
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Appendices

Appendix A Data Validation Reports

Appendix B Field Documentation

B1. Log of Daily Notice of Field Activities

B2. Sampling Forms

B3. Field Change Request and Nonconformance/ Corrective Action Reports

B4. Survey Data

B5. Investigation-Derived Waste Logs

Appendix C Photographic Log

Appendix D Laboratory Reports

Appendix E Boring Logs 

Appendix F Analytical Results

Figures

Figure 2-1 Facility Location

Figure 2-2 Facility Topography

Figure 2-3 Groundwater Features

Figure 2-4 Groundwater Elevation Contours, June 2021 

Figure 2-5 Surface Water Features

Figure 3-1 Areas of Interest

Figure 5-1 Site Inspection Sample Locations

Figure 6-1 PFOA Detections in Soil

Figure 6-2 PFOS Detections in Soil

Figure 6-3 PFBS Detections in Soil

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

Figure 7-1 Conceptual Site Model, AOI 1

Figure 7-2 Conceptual Site Model, AOI 2

Figure 7-3 Conceptual Site Model, AOI 3

Figure 7-4 Conceptual Site Model, Facility Boundary

Tables

Table ES-1 Screening Levels (Soil and Groundwater)

Table ES-2 Summary of Site Inspection Findings

Table ES-3 Site Inspection Recommendations

Table 5-1 Site Inspection Samples by Medium

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

Elevations

Table 6-1 Screening Levels (Soil and Groundwater)

Table 6-2 PFAS Detections in Surface Soil

Table 6-3 PFAS Detections in Shallow Subsurface Soil

Table 6-4 PFAS Detections in Groundwater

Table 8-1 Summary of Site Inspection Findings

Table 8-2 Site Inspection Recommendations
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Acronyms and Abbreviations

% percent

°C degrees Celsius

°F degrees Fahrenheit

μg/kg micrograms per kilogram

6:2 FTS 6:2 Fluorotelomer sulfonic acid

8:2 FTS 8:2 Fluorotelomer sulfonic acid

AECOM AECOM Technical Services, Inc.

Aerostar Aerostar SES LLC

AFFF aqueous film forming foam

AFRPA Air Force Real Property Agency

ANG Air National Guard

AOI Area of Interest

ARNG Army National Guard

bgs below ground surface 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CoC chain of custody

CRAA Columbus Regional Airport Authority

CSM conceptual site model

DA Department of the Army

DERR Division of Environmental Response and Revitalization

DoD Department of Defense

DPT direct push technology

DQI data quality indicator

DQO data quality objective

DUA data usability assessment

DVR data validation report 

EIS extraction internal standards

ELAP Environmental Laboratory Accreditation Program

EM Engineer Manual

EPA Environmental Protection Agency

ERB equipment rinsate blank

FedEx Federal Express Corporation

FRB field reagent blank

FTA Fire Training Area

GPRS Ground Penetrating Radar Services, LLC

HA Health Advisory

HDPE high-density polyethylene

HEF high expansion foam

IDW investigation-derived waste

IIS injection internal standards

ITRC Interstate Technology Regulatory Council

LC/MS/MS liquid chromatography with tandem mass spectrometry

LCS laboratory control spike
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LCSD laboratory control spike duplicate

LOD limit of detection

LOQ limit of quantitation

MDL method detection limit

MS matrix spike

MSD matrix spike duplicate

NELAP National Environmental Laboratory Accreditation Program

NEtFOSAA N-ethyl perfluorooctanesulfonamidoacetic acid

ng/L nanograms per liter

NMeFOSAA N-methyl perfluorooctanesulfonamidoacetic acid

NOAA National Oceanic and Atmospheric Administration

ODGS Ohio Division of Geological Survey

OHANG Ohio Air National Guard

OHARNG Ohio Army National Guard

OSD Office of the Secretary of Defense

PA Preliminary Assessment

PFAS per- and polyfluoroalkyl substances

PFBA perfluorobutyrate

PFBS perfluorobutanesulfonic acid

PFCs perfluorinated compounds

PFDA perfluorodecanoic acid

PFDoA perfluorododecanoic acid

PFHpA perfluoroheptanoic acid

PFHxA perfluorohexanoic acid

PFHxS perfluorohexanesulfonic acid

PFNA perfluorononanoic acid

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

PFPeA perfluoropentanoic acid

PFTeDA perfluorotetradecanoic acid

PFTrDA perfluorotridecanoic acid

PFUdA perfluoroundecanoic acid

PID photoionization detector

PQAPP Programmatic UFP-QAPP

PVC polyvinyl chloride

QA quality assurance

QAPP Quality Assurance Project Plan

QC quality control

QSM Quality Systems Manual

RAE Rickenbacker Army Enclave

RI Remedial Investigation

RIA Rickenbacker International Airport

RPD relative percent differences

SI Site Inspection

SL screening level
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SOP standard operating procedure

TCRA Time-Critical Removal Action

TOC total organic carbon

TPP Technical Project Planning

UCMR Unregulated Contaminant Monitoring Rule

UFP Uniform Federal Policy

US United States

USACE United States Army Corps of Engineers

USCS Unified Soil Classification System

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service

WWTP Wastewater Treatment Plant
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Executive Summary

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

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

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

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

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

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

the Rickenbacker Army Enclave (RAE) in Columbus, Ohio. Rickenbacker Army Enclave will also 

be referred to as the “facility” throughout this document.

RAE is located at 8174 S Access Road, in Franklin County, Columbus, Ohio, approximately 12 

miles southeast of downtown Columbus, Ohio (Figure 2-1). The facility primarily supports 

readiness and training activities associated with helicopter missions. Helicopter and aircraft 

parking, maintenance, and fueling, administration, billeting/transient barracks, and mission 

support facilities are all Ohio ARNG (OHARNG) operations occurring at RAE. 

During the PA for PFAS, three potential PFAS release areas were identified: the C26 Hangar, 

Drainage Ditch, and Helicopter Ramp Area (AECOM, 2019). PFAS-containing Jet-X foam was

released inside the C26 Hangar during a test of the HEF fire suppression system, and PFAScontaining aqueous film forming foam (AFFF) could have potentially been released due to storage 

of Tri-MaxTM tanks at the Helicopter Ramp Area. Any potential spills or discharges on either ramp 

area would eventually flow into the Drainage Ditch. The potential PFAS release areas were 

designated into three Areas of Interest (AOIs), which were investigated during the SI. The SI field 

activities were conducted from 14 to 16 June and 25 August 2021 and included the collection of 

soil and groundwater samples.

To fulfill the project Data Quality Objectives set forth in the approved SI Quality Assurance Project 

Plan Addendum (AECOM, 2021a), samples were collected and analyzed for a subset of 18 PFAS 

by liquid chromatography with tandem mass spectrometry compliant with Quality Systems Manual 

5.3 Table B-15. The 18 PFAS analyzed as part of the ARNG SI program are specified in Section 

5.7 of this Report.

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

SLs for soil and groundwater, as described in a memorandum from the Office of the Secretary of 

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

program under which this SI was performed follows this DoD policy. Should the maximum site 

concentration for sampled media exceed the SLs established in the OSD memorandum and there 

is a release identified that is likely attributed to ARNG activities, the AOI will proceed to the next 

phase under CERCLA. The SLs established in the OSD memorandum apply to three compounds: 

PFOS, PFOA, and PFBS.

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

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

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

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

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

• At AOI 1, refusal was encountered, and groundwater was unable to be sampled at the 

C26 Hangar potential PFAS release area. Based on the results of the SI, further evaluation 

of groundwater at AOI 1 is recommended to make site-related remedial decisions.

• At AOI 2, PFOA, PFOS, and PFBS were detected in groundwater at the Drainage Ditch

potential PFAS release area below the OSD SLs. Although no PFAS analytes exceeded 
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their respective SLs at AOI 2, the shallow depth to groundwater encountered and fat clays 

observed at location AOI02-01 indicate that it is possible groundwater was sampled from 

a perched water bearing unit. Therefore, there is insufficient information to make a 

remedial decision and further evaluation of groundwater at AOI 2 is recommended.

• At AOI 3, PFOS, PFOA, and PFBS were non-detect in groundwater at the Helicopter 

Ramp Area potential PFAS release area; however, PFOS in groundwater exceeded the 

SL at facility boundary location, RAE-01. Although the groundwater flow direction 

observed in onsite temporary wells was to the west, a 2018 Base Realignment and 

Closure (BRAC) Report for the Rickenbacker Air National Guard (ANG) Base projects that 

groundwater across the southern portion of the airport flows southwest (Aerostar, 2018). 

If groundwater flows southwest across the eastern portion of the RAE, temporary well 

location RAE-01 may be considered downgradient of AOI 3. Therefore, based on the 

presence of PFOS in groundwater at location RAE-01, there is insufficient information to 

make a remedial decision and further evaluation of groundwater at AOI 3 is recommended. 

• At the Facility Boundary location, RAE-01, PFOS was detected in exceedance of the OSD 

SL at 75.1 nanograms per liter (ng/L), and PFOA was detected at 13.3 ng/L. PFOS 

detections at location RAE-01 indicate that offsite PFAS sources may be contributing to 

PFAS concentrations in environmental media at the facility; however, it is also possible 

that groundwater flows southwest across the facility based on the 2018 BRAC Report for 

the ANG Base. If groundwater flows southwest across the facility, then location RAE-01 

would be considered downgradient from AOI 3. Due to this uncertainty and the 

concentrations of PFOS in groundwater at location RAE-01 exceeding the SL, further 

evaluation of the Facility Boundary is recommended.

• The detected concentrations of PFOA, PFOS, and PFBS in soil at all AOIs were below the

SLs. 

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

models (CSMs) developed and revised in light of the SI findings, there is potential for exposure 

to drinking water receptors caused by DoD activities at or adjacent to the facility.

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

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

information is required to make remedial decisions for all AOIs at this facility.
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Table ES-1: Screening Levels (Soil and Groundwater)

Analyte

Residential

(Soil)

(μg/kg)a,b

0-2 feet bgs

Industrial/ 

Commercial 

Composite 

Worker

(Soil)

(μg/kg)a,b

2-15 feet bgs

Tap Water

(Groundwater)

(ng/L)a,b

PFOA 130 1,600 40

PFOS 130 1,600 40

PFBS 1,900 25,000 600

Notes:

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

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

September 2021.

b.) USEPA. 2016a. Drinking Water Health Advisory (HA) for Perfluorooctanoic Acid (PFOA). Office of Water (4304T). Health and Ecological 

Criteria Division, Washington, DC 20460. USEPA Document Number: 822-R-16-005. May 2016. / USEPA. 2016b. Drinking Water HA for 

Perfluorooctane Sulfonic Acid (PFOS). Office of Water (4304T). Health and Ecological Criteria Division, Washington, DC 20460. USEPA

Document Number: 822-R-16-004. May 2016.

Table ES-2: Summary of Site Inspection Findings

AOI Potential PFAS 

Release Area

Soil –

Source Area

Groundwater –

Source Area

Groundwater –

Facility Boundary

1 C26 Hangar N/A(1) N/A

2 Drainage Ditch

3 Helicopter Ramp Area

Facility 

Boundary

Off-Facility/ 

Upgradient

Legend:

N/A = not applicable

(1) Groundwater was not encountered at AOI 1; therefore, groundwater samples could not be collected.

= PFOA, PFOS, and/or PFBS detected; exceedance of the screening levels

= PFOA, PFOS, and/or PFBS detected; no exceedance of the screening levels

= PFOA, PFOS, and/or PFBS not detected
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Table ES-3: Site Inspection Recommendations

AOI Description Rationale Future Action

1 C26 Hangar

Unable to collect 

groundwater samples. No 

exceedances of SLs in soil. 

Consider further groundwater 

evaluation.

2 Drainage Ditch

Detections in groundwater 

below SLs at potential

source area. Additionally, 

groundwater samples 

collected could possibly 

represent perched water, 

not water table. No 

exceedances of SLs in soil. 

Consider further groundwater 

evaluation.

3 Helicopter Ramp 

Area

No detections in 

groundwater; however, 

exceedances are present in 

potential downgradient 

sample location. No 

exceedances of SLs in soil.

Consider further groundwater 

evaluation.

Facility 

Boundary 

Off-Facility/ 

Upgradient

Exceedances of SL in 

groundwater at source 

area. No exceedances of 

SLs in soil.

Consider further groundwater 

evaluation.
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1. Introduction

1.1 Project Authorization

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

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

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

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

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

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

Rickenbacker Army Enclave (RAE) in Columbus, Ohio. The RAE is also referred to as the “facility”

throughout this document.

The SI project elements were performed in compliance with Comprehensive Environmental 

Response, Compensation, and Liability Act (CERCLA; US Environmental Protection Agency 

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

Plan (40 Code of Federal Regulations Part 300; USEPA, 1994), and in compliance with US 

Department of the Army (DA) requirements and guidance for field investigations including specific 

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

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

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

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

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

1.2 SI Purpose

A PA was performed at RAE (AECOM, 2019) that identified three potential PFAS release areas 

at the facility, which were designated into three Areas of Interest (AOIs). The objective of the SI is 

to identify whether there has been a release to the environment from the AOIs and determine the 

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

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

SI has five goals: 

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

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

2. Determine the potential need for a removal action;

3. Collect or develop data to evaluate potential release;

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

Remedial Investigation (RI), if determined necessary; and

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

associated with the Department of Defense (DoD).

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

potential off-facility PFAS sources. 
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2. Facility Background

2.1 Facility Location and Description

RAE is located at 8174 S Access Road, in Franklin County, Columbus, Ohio, approximately 12 

miles southeast of downtown Columbus, Ohio (Figure 2-1). The facility primarily supports 

readiness and training activities associated with helicopter missions. Ohio ARNG (OHARNG)

operations at RAE include helicopter and aircraft parking, maintenance, fueling, administration, 

billeting/transient barracks, and mission support facilities. 

The area comprising RAE was originally named the “Northwest Training Center of the Army Air

Corps” in 1942, later renamed to the “Lockbourne Air Force Base” in 1948, and finally renamed 

“Rickenbacker Air Force Base” in 1974 (Air Force Real Property Agency [AFRPA], 2007). The 

base was transferred to the Ohio Air National Guard (OHANG) in 1980 and renamed the 

“Rickenbacker Air National Guard Base”. A portion of the property was transferred to the 

Rickenbacker Port Authority in 1984, at which time Rickenbacker International Airport (RIA) was 

established. RIA primarily serves as a cargo-only airport for the City of Columbus, allowing 

government, private, and commercial cargo planes to transport goods internationally. In 1987, the 

ARNG entered into a federal-state agreement with the State of Ohio for the construction of an 

Army Aviation Support Facility on land owned by the Rickenbacker Air National Guard (ANG)

Base. An indefinite license was granted in 1998 for the use, occupancy, training, and support of 

126 acres for the OHARNG.

In 2003, the Rickenbacker Port Authority merged with the Columbus Airport Authority to form the

Columbus Regional Airport Authority (CRAA). The CRAA currently owns and operates RIA, of 

which the OHARNG is an adjacent tenant. RAE is located within the Rickenbacker ANG Base as 

part of a joint military facility, with additional tenants including the CRAA, the OHANG, a Naval 

Reserve Center, and various commercial businesses (USACE, 2017). RAE is part of the 126-acre 

parcel of land that was licensed to the ARNG per the aforementioned August 1998 agreement 

(AECOM 2019, Appendix A).

2.2 Facility Environmental Setting

RAE is located in the Interior Plains region of Ohio. The Interior Plains encompass most of the 

western part of the state and are characterized by lower relief than the Appalachian Highlands to 

the east. The terrain around the facility exhibits moderately low relief, with a broad regional slope 

to the southeast towards the Scioto Valley. The elevation of the facility is approximately 740 feet 

above mean sea level (Engineering-Science, 1988). The facility is surrounded by farmland and 

deciduous forest to the west, and by RIA to the east.

2.2.1 Geology

RAE lies within the Central Lowland physiographic province, Columbus Lowland district. The 

Columbus Lowland is a lowland area with many larger streams that is bounded to the north by 

Powell Moraine, to the east/south by the Berea and Allegheny Escarpments, and to the west by 

the flatter and higher Darby Plain (Ohio Division of Geological Survey [ODGS], 1998).

RAE is situated on loamy, medium-lime, Wisconsinan-age clay glacial till and outwash (ODGS, 

1998); the glacial drift unit is generally 211 to 260 feet thick (ODGS, 2004). The glacial drift unit is 

underlain by the Ohio Shale Unit, an Upper Devonian sedimentary bedrock unit composed 

primarily of black shale. The Chagrin Member of the Ohio Shale also contains some siltstone and 

very fine-grained sandstone (Slucher, E.R. et al., 2006).
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Soil borings completed during the SI found the majority of the uppermost 25 feet of this unit consist 

of lean clay with sand and fat clay with sand. The borings were completed at depths between 5 

and 25 feet below ground surface (bgs). Varying gravel content was observed in these clay layers, 

ranging between 5 and 25 percent (%). Gravel size generally increased with depth. Isolated 

lenses of cobble, coarse and angular gravel were observed at thicknesses ranging from 1 to 2 

inches at varying depths between 4.3 and 13.0 feet bgs. Samples for grain size analysis were 

collected at three locations, AOI01-01, AOI03-01, and RAE-01, and analyzed via American 

Society for Testing and Materials (ASTM) Method D-422. The results indicate that the soil samples 

are comprised primarily of silt (41.35% to 50.41%), These results and facility observations are 

consistent with the understood land fill material and glacial outwash environment. Boring logs are 

presented in Appendix E and grain size results are presented in Appendix F. 

2.2.2 Hydrogeology

RAE is not located on a principal aquifer system due to the low permeability of the underlying 

shale bedrock. The surficial aquifer system consists of regionally extensive, thick, permeable 

deposits of sand and gravel that may be overlain by low-permeability glacial till. Coarse deposits 

located at depths of 30 to 200 feet bgs may yield as much as 500 gallons per minute (Schmidt, 

1958). Groundwater flow is generally to the west, towards Big Walnut Creek (Figure 2-3, Figure 

2-4).

RAE obtains its drinking water from the City of Columbus public water system, which utilizes both 

surface water and groundwater for drinking water. The City of Columbus has three main plants 

that treat all source water; RAE receives water from the Parsons Avenue Water Plant, 

approximately 5 miles northwest of the facility, which utilizes groundwater for drinking water and 

serves southeastern Franklin County (City of Columbus, 2018). No potable water wells are 

located within RAE; however, domestic wells and monitoring wells exist within 4 miles of the facility 

(Figure 2-3).

The City of Lockbourne is located approximately 3,500 feet west of RAE. Like the RAE facility, 

Lockbourne is connected to the City of Columbus public drinking water system; however, the Ohio 

State Water Well database shows that several private drinking water wells are located within 1 

mile of the facility. One domestic well is reported 0.5 miles north of the facility, while several other 

domestic wells located within 1 mile northwest of RAE, in the direction of groundwater and surface 

water flow.

The Unregulated Contaminant Monitoring Rule (UCMR) sampling program was an addition to the 

1996 Safe Drinking Water Act which requires every five years the USEPA issue a new list of no 

more than 30 unregulated contaminants to be monitored by public water systems. PFAS were

added as part of the UCMR 3 list (2012). The UCMR 3 dataset was evaluated to determine which 

public water systems were sampled for PFAS within a 20-mile radius of the facility. Based on this 

rule, the City of Columbus public drinking water was sampled. The sampling results for PFOA and 

PFOS were non-detect. No other public water system within 20 miles of the facility had detects 

for PFOA or PFOS (USEPA, 2017a). PFAS analyses performed in 2016 had method detection 

limits that were higher than currently achievable. Thus, it is possible that low concentrations of 

other PFAS were not detected during the UCMR3 but might be detected if analyzed today.

Depths to water measured in June 2021 during the SI field effort ranged from 7.30 feet bgs to 

3.65 feet above ground surface (water level measured in temporary monitoring well casing stickup extending above ground surface at RAE-01). Groundwater elevation contours from the SI are 

presented on Figure 2-4 and indicate localized groundwater flow direction is generally to the 

northwest. A 2018 Base Realignment and Closure (BRAC) Report for the Rickenbacker ANG 

Base interpreted groundwater flowing southwest across the southern portion of the airport, 

including the RAE facility (Aerostar, 2018). This 2018 BRAC Report interpretation did not utilize 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 2-3

any monitoring wells within 0.5 miles of the RAE facility. Due to the complexity of the geology and 

hydrogeology in the immediate area, there is a level of uncertainty with respect to the groundwater 

flow direction immediately beneath the facility. This uncertainty will be acknowledged as a data 

gap that will need to be addressed in the next phase of work. 

2.2.3 Hydrology

Regional surface water features include Big Walnut Creek and the Scioto River. Big Walnut Creek 

converges with the Scioto River approximately 2.8 miles from the facility.

RAE employs a series of drainage ditches to convey runoff off-site. One drainage ditch originates 

on OHANG property, enters the facility from the north, runs parallel to the northwest facility 

boundary, and exits the facility in the western portion. A second drainage ditch originates in the 

southern portion of the facility and flows northwest, where it converges with the first drainage 

ditch, at which point it exits the facility on the northwest boundary. The drainage ditch system 

conveys runoff to Big Walnut Creek, which flows west towards the Scioto River, approximately 

1.4 miles from the property boundary (Figure 2-5).

2.2.4 Climate

The climate at RAE is temperate, humid subtropical, with cool to cold winters and long, hot 

summers. The average temperature is 52.7 degrees Fahrenheit (°F), with summer highs of 84.9 

°F and winter lows of 21.1 °F. Average annual precipitation is 40.11 inches (National Oceanic and 

Atmospheric Administration [NOAA], 2021).

2.2.5 Current and Future Land Use

RAE is located adjacent to RIA and an OHANG enclave, surrounded by small residential and 

industrial areas. The northeast boundary of RAE connects with the southwest boundary of the 

OHANG enclave. Directly east of RAE lies Runways 5 and 23, which are owned and operated by 

RIA. Within RAE are several hangars, storage buildings, and a helicopter ramp area. RAE 

supports the operation of helicopter and aircraft parking, maintenance, and fueling, 

billeting/transient barracks, and mission support facilities. Operations within the facility will 

continue to support the aviation operations for the duration of the lease, which was issued for an 

indefinite term. Future land use is not anticipated to change.

2.2.6 Sensitive Habitat and Threatened/ Endangered Species 

The following birds, plants, mammals, and reptiles are federally endangered, threatened, 

proposed, and/ or are listed as candidate species in Franklin County, Ohio (US Fish and Wildlife 

Service [USFWS], 2021). 

• Insects: Monarch butterfly, Danaus plexippus (candidate)

• Mammals: Northern long-eared bat, Myotis septentrionalis (threatened); Indiana bat, Myotis 

2-3odalist (endangered)

• Fishes: Scioto madtom (Noturus trautmani)

• Clams: Rayed bean, Villosa fabalis (endangered); Northern riffleshell, Epioblasma torulosa 

rangiana (endangered); Rabbitsfoot, Quadrula cylindrica cylindrica (threatened); Clubshell, 

Pleurobema clava (endangered); Snufflbox mussel, Epioblasma triquetra (endangered)

• Flowering plants: Eastern prairie fringed orchid, Platanthera leucophaea (threatened)
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 2-4

2.3 History of PFAS Use 

Three potential PFAS release areas were identified at RAE during the PA where aqueous film 

forming foam (AFFF) may have been used, stored, and released historically (AECOM, 2019). 

PFAS-containing materials were potentially released to soil and groundwater, surface water, and 

sediment within the boundary of RAE through a fire suppression system testing, AFFF storage,

and storm water conveyance. The potential PFAS release areas were grouped into three AOIs 

based on preliminary data and presumed groundwater flow direction. These AOIs are described 

in Section 3.
Legend

Facility Boundary

0 0.5 1 2

Miles

­12420 Milestone Center Drive

Germantown, MD 20876

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

EG

11/18/2021

11/18/2021

NOTES Site Inspection for PFAS at Rickenbacker Army Enclave, OH

11/18/2021

1:63,360

PM CM 11/18/2021

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Fig_2-1_Rickenbacker_Facility_Location.mxd

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

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

Figure 2-1

Facility Location

Rickenbacker Army Enclave

^_

AECOM 2-5
Legend

Facility Boundary

0 250 500 1,000

Feet

­12420 Milestone Center Drive

Germantown, MD 20876

CLIENT

REVISED

SCALE

ARNG

GIS BY

CHK BY

MS

EG

11/18/2021

11/18/2021

NOTES Site Inspection for PFAS at Rickenbacker Army Enclave, OH

11/18/2021

1:6,000

PM CM 11/18/2021

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Fig_2-2_Rickenbacker_SI_Facility_Topography.mxd

Base Map: USGS The National Map: National

Boundaries Dataset, 3DEP Elevation Program,

Figure 2-2

Facility Topography

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Big R un

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Facility Boundary

Water Body

Wetland

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!P Domestic Well

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A! Monitoring Well/Piezometer

A! Other Well

0 0.75 1.5 3

Miles

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Germantown, MD 20876

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Figure 2-3

Groundwater Features

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

Geographics, CNES/Airbus DS, USDA, USGS,

AECOM 2-7
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718

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Legend

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!? Soil Boring/Temporary Monitoring Well

Facility Boundary

Groundwater Elevation Contour

Inferred Groundwater Elevation Contour

Localized Groundwater Flow Direction

0 225 450 900

Feet

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

Geographics, CNES/Airbus DS, USDA, USGS,

Figure 2-4

Groundwater Elevation Contours -

June 2021

AECOM 2-8
Grove Run-Scioto

River Watershed

Town of

Lockbourne-Alum

Creek Watershed

Mud Run-Walnut

Creek Watershed

Grant Run-Scioto

River Watershed

Big Run-Walnut

Creek Watershed

Mud Run

S c ioto River

Peters Run

Mud Run

Big Walnut Creek

Walnut Creek

Legend

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Surface Water Flow Direction

0 0.5 1 2

Miles

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

Geographics, CNES/Airbus DS, USDA, USGS,

Figure 2-5

Surface Water Features

AECOM 2-9
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 2-10

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Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 3-1

3. Summary of Areas of Interest

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

findings, three potential PFAS release areas, the C26 Hangar, Drainage Ditch, and Helicopter 

Ramp Area, were identified at RAE and grouped into three separate AOIs (AECOM, 2019). The 

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

3.1 AOI 1 

AOI 1 consists of one potential PFAS release area. This potential release area is described below. 

3.1.1 C26 Hangar

AOI 1 is the C26 Hangar. The C26 Hangar is located on the northeast side of RAE and was 

constructed in 2003. The hangar is primarily used for the storage of small aircraft and various 

equipment. Minor aircraft maintenance also occurs within this building. 

The C26 Hangar included a fire suppression system with 2.75% Jet-X high expansion foam (HEF) 

installed between 2007 and 2008. The Jet-X holding tank has a capacity of approximately 900 

gallons. According to interviewees, a test of the system that involved a release of an unknown 

amount of Jet-X foam from the fire suppression system was conducted following installation 

(AECOM, 2019). The hangar doors were closed during this initial testing, and all material from the 

suppression system dissipated into the floor drains of the hangar that leads to the sanitary sewer. 

RAE and the surrounding airport are connected to the Big Walnut Augmentation/Rickenbacker 

Interceptor sewer that drains to the City of Columbus’ Southerly Wastewater Treatment Plant 

(WWTP). The Southerly WWTP is located approximately 12 miles west of RAE. All waste treated 

at the Southerly WWTP is discharged to the Scioto River, west of RAE, which is commonly used 

for recreational activities. No other spills or releases have been reported from this hangar.

3.2 AOI 2 

AOI 2 consists of one potential PFAS release area. This potential release area is described below.

3.2.1 Drainage Ditch

AOI 2 is a stormwater drainage ditch that originates on OHANG property. The ditch enters 

OHARNG property from the north and runs parallel to the northwest boundary of the facility. 

Upgradient of RAE, stormwater runoff from OHANG hangars and ramp areas discharges into this 

ditch, which then flows through the OHARNG property. The drainage ditch flows southwest, 

eventually exiting the facility boundary near the Lockbourne Air Force Base Landfill. Two small 

detention ponds along the southwest edge of the OHARNG pavement, and two small drainage 

channels north of the helicopter ramp area connect to this stormwater drainage ditch. Any 

potential spills or discharges on either ramp area or near these drainage channels would 

eventually flow into the stormwater drainage ditch. 

A second drainage ditch originates in the southern portion of the facility and flows northwest, 

where it converges with AOI 2 and exits the facility on the northwest boundary. As mentioned 

above, any releases between the two properties would likely be captured in the storm drain 

system, which then discharges to AOI 2, and eventually conveys runoff to Big Walnut Creek, 

approximately 1.4 miles from the property boundary. 

An SI performed at the OHANG facility by Aerostar in 2017 showed several potential AFFF 

releases that could have impacted this stormwater drainage system (Aerostar, 2018). Additionally, 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 3-2

any potential release from RAE would be captured in surrounding storm drains and discharged 

into AOI 2. 

3.3 AOI 3 

AOI 3 consists of one potential PFAS release area. This potential release area is described below. 

3.3.1 Helicopter Ramp Area

AOI 3 is a helicopter ramp area south of Building 918 that contained between nine to eleven 

mobile Tri-MaxTM tanks from approximately 2002 to 2013. While exact specifications for these TriMaxTM tanks, including concentration and quantity, were not available, they were likely PFAScontaining AFFF tanks. Based on interviewee knowledge, these tanks were never used or 

deployed for fire training purposes or emergency response incidents. Interviewees confirmed that 

these tanks remained outside during their storage on the ramp, but they could not confirm if the 

tanks were regularly maintained. 

The north and southwest corners of AOI 3 each contain one drainage channel that eventually 

discharges into AOI 2. Any potential spills or discharges on the helicopter ramp area or near the 

drainage channels would eventually flow into AOI 2. The drainage channels conveying runoff from 

AOI 3 to AOI 2 also drain ramp and flightline areas to the northeast on the adjacent ANG Base. 

Runoff from those adjacent areas are also ultimately conveyed to AOI 2. 

3.4 Facility Boundary

The Facility Boundary consists of one potential PFAS release area. This potential release area is 

described below.

3.4.1 Off-Facility/ Upgradient Potential Release Area

A former ANG Fire Training Area (FTA) sits approximately 5,000 feet east of RAE, on 

Rickenbacker International Airport property. A spill or release from this off-facility source has the 

potential to migrate onto RAE and subsequently impact RAE groundwater. This potential offfacility PFAS source was not identified as an AOI during the PA. After further review of aerial 

photographs and inferred groundwater flow direction, the area located approximately 5,000 feet 

east of the facility boundary may present a potential source of PFAS migrating onto RAE.

A 2018 BRAC Report for the ANG Base projects groundwater flowing to the southwest across the 

southern portion of the airport, including the RAE facility (Aerostar, 2018). Based on this 

groundwater flow projection, the area identified as the Upgradient Facility Boundary may not be 

upgradient of all RAE AOIs. There is a level of uncertainty with respect to the interpreted 

groundwater flow direction observed in onsite temporary wells. This uncertainty will be 

acknowledged as a data gap that will need to be addressed in the next phase of work. The 

Upgradient Facility Boundary is conservatively considered potentially downgradient from AOI 3 

for the purpose of conceptual site model (CSM) evaluation in this report. 
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AOI 2

AOI 3

Hangar 883

Concrete Ramp/Apron

Hangar 885

Hangar 888

Building 820 - Current Fire Station

Helicopter Ramp Area

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ANG Old FTA

Building 918

Building 931

C26 Hangar

Grove Run-Scioto

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Town of

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Big Run-Walnut

B

Creek Watershed ig Walnut Creek

Legend

Area of Interest

Potential PFAS Release

No Suspected Release

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Surface Water Flow Direction

Localized Groundwater Flow Direction

!P Domestic Well

A! Monitoring Well/Piezometer

A! Other Well

0 750 1,500 3,000

Feet

Areas of Interest

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

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1:18,000

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

Former Lockbourne 

Air Force Base Landfill

AECOM 3-3
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 3-4

THIS PAGE INTENTIONALLY BLANK
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 4-1

4. Project Data Quality Objectives

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

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

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

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

4.1 Problem Statement

The following problem statement was developed during project planning:

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

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

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

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

the federal and state level continues to evolve. 

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

SLs for soil and groundwater, as described in a memorandum from the Office of the Secretary of 

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

program under which this SI was performed follows this DoD policy. Should the maximum site 

concentration for sampled media exceed the SLs established in the OSD memorandum, the AOI

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

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

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

2018): 

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

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

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

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

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

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

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

considered possible source areas.”

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

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

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

contamination.”

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

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

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

4.2 Goals of the Study

The following goals were established for this SI:

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

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

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

Rickenbacker Army Enclave, Columbus, OH

AECOM 4-2

3. Determine the potential need for a Time Critical Removal Action (TCRA) (applies to

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

alternative water supplies or wellhead treatment.

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

of a RI (if determined necessary).

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

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

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

other DoD facilities).

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

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

4.3 Information Inputs

Primary information inputs included:

• The PA for RAE (AECOM, 2019);

• The AFFF SI for the Base Realignment and Closure (BRAC) portion of the ANG base

(Aerostar, 2018);

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

with the site-specific Uniform Federal Policy (UFP)-Quality Assurance Project Plan (QAPP)

Addendum (AECOM, 2021a); and

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

parameters measured at the time of sampling.

4.4 Study Boundaries

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

was not included in the scope of this SI. If future off-facility sampling is required, the proper 

stakeholders will be notified, and necessary rights of entry will be obtained by ARNG with property 

owner(s).

4.5 Analytical Approach

Samples were analyzed by Pace Analytical Gulf Coast, accredited under the DoD Environmental 

Laboratory Accreditation Program (ELAP; Accreditation Number 74960) and the National 

Environmental Laboratory Accreditation Program (NELAP; Certificate Number 01955). Data were 

compared to applicable SLs and decision rules as defined in the SI QAPP Addendum (AECOM, 

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

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

based on the following:

Groundwater:

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

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

Rickenbacker Army Enclave, Columbus, OH

AECOM 4-3

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

and downgradient of the potential release areas?

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

Soil:

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

bgs)?

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

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

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

Groundwater was encountered at approximately 4.64 to 7.30 feet bgs at AOI 2 and AOI 3, 

respectively. Positive hydraulic head was observed at RAE-01, where groundwater was measured 

at 3.65 feet above ground surface (water level measured from temporary monitoring well casing 

stick-up extending above the ground surface at RAE-01). 

4.6 Data Usability Assessment

The Data Usability Assessment (DUA) is an evaluation at the conclusion of data collection 

activities that uses the results of both data verification and validation in the context of the overall 

project decisions or objectives. Using both quantitative and qualitative methods, the assessment 

determines whether project execution and the resulting data have met 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.

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

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

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

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

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

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

presents explanations for all qualified data in greater detail.

4.6.1 Precision

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

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

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

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

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

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

to analysis as a legacy requirement of DoD QSM 5.1 to measure relative responses of target 

analytes. Even though not required under DoD QSM 5.3, the IIS are still added to the sample 

after extraction as an additional quality control (QC) measure. The IIS percent recoveries were 

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

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

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

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

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

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

Rickenbacker Army Enclave, Columbus, OH

AECOM 4-4

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

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

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

analysis at a rate of 5%. The MS/MSDs samples were within the project established precision 

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

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

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

PFAS and general chemistry parameters. The field duplicate samples were within the project 

established precision limits presented in the QAPP Addendum (AECOM, 2021a) with limited 

exceptions. Three separate field duplicate pairs displayed positive results in one sample and nondetect results in the other sample. The positive associated field duplicate pair results were 

qualified “J”, while non-detects were qualified “UJ”. The qualified field duplicate pair results should 

be considered usable as estimated values. 

4.6.2 Accuracy

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

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

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

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

surrogates.

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

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

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

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

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

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

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

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

ionization efficiencies, and other associated preparation and analytical anomalies. The EIS area 

counts were within the project established precision limits presented in the QAPP Addendum 

(AECOM, 2021a) with several exceptions. The field sample result associated with low EIS area 

counts were non-detect and were qualified as estimate and should be considered usable as 

qualified. 

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

demonstrated that the analytical system was in control for the matrix being tested.

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

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

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

the QAPP Addendum (AECOM, 2021a). 

4.6.3 Representativeness

Representativeness qualitatively expresses the degree to which data accurately reflect site 

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

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

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

interferences. 
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Relating to the use of standard analytical methods, the laboratory followed the method as 

established in PFAS by liquid chromatography with tandem mass spectrometry (LC/MS/MS) 

Compliant with Quality Systems Manual (QSM) 5.3 Table B-15, including the specific preparation 

requirements (i.e. ENVI-Carb or equivalent used), mass calibration, spectra, all the ion transitions 

identified in Table B-15 were monitored, standards that contained both branch and linear isomers 

when available were used, and isotopically labeled standards were used for quantitation.

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

duplicates were collected at a rate of 10% for all field samples, while MS/MSD samples were 

collected at a rate of 5%. All preservation techniques were followed by the field staff, and all 

technical and analytical holding times were met by the laboratory. The laboratory used approved 

standard methods in accordance with the QAPP Addendum (AECOM, 2021a) for all analyses.

Instrument blanks and method blanks were prepared by the laboratory in each batch as a negative 

control. Several laboratory and method blanks displayed concentrations for multiple target 

analytes greater than the detection limits. Five investigative field samples (RAE-AOI01-02-SB-8-

10, RAE-AOI03-01-SB-0-2, RAE-AOI03-01-SB-4-6, RAE-AOI03-02-SB-0-2, and RAE-AOI03-02-

SB-13-15 DUP) had a field sample result for PFOS qualified as a likely false positive due to a 

blank detection. 

Equipment blanks and field blanks were also collected for groundwater and soil samples. The 

field sample results associated to these blanks were non-detect or displayed concentrations 

greater than five times the blank detections; no impact on the data is anticipated. 

A sample of the water used for decontamination of the drill rig was collected in advance of the 

field effort. The drill rig decontamination sample RAE-PW-01 displayed concentrations greater 

than the detection limit for several target analytes. The associated field sample results were

greater than five times the concentration found in the decontamination sample; no impact on the 

data is anticipated.

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

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

exceptions. Three PFAS field samples were re-extracted and reanalyzed outside of technical 

holding time due to QC failures. For all samples with re-extracted results, the data reviewer 

recommended one usable result from either the initial or re-extracted analysis based on 

professional judgement of data quality. Additionally, the holding time for pH analysis is 

“immediate”, all field samples analyzed for pH were qualified “J” and should be considered usable 

as estimated values.

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

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

4.6.4 Comparability

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

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

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

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

considered comparable to ongoing investigations.

4.6.5 Completeness

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

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

that met system QC acceptance criteria for all samples tested. Project completeness was 
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AECOM 4-6

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

parameter is as follows, if applicable: 

• PFAS in groundwater by DoD QSM Table B-15 at 100%

• PFAS in soil by DoD QSM Table B-15 at 100%

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

• Total organic carbon (TOC) by USEPA Method 9060 at 100%

Certain soil samples were unable to be collected due to groundwater elevation being higher than 

anticipated at one soil boring location. Three groundwater samples were unable to be collected 

due to the absence of surficial groundwater at boring locations. These deviations from the SI 

QAPP Addendum are described further in Section 5.8. 

4.6.6 Sensitivity

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

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

of QC measures for determining sensitivity include laboratory fortified blanks, a method detection 

limit (MDL) study, and calibration standards at the limit of quantitation (LOQ). In order to meet the 

needs of the data users, project data must meet the measurement performance criteria for 

sensitivity and project LOQs specified in the QAPP Addendum (AECOM, 2021a). The laboratory 

provided the requested MDL studies and provided applicable calibration standards at the LOQ. In 

order to achieve the DQOs for sensitivity outlined in the QAPP Addendum (AECOM, 2021a), the

laboratory reported all field sample results at the lowest possible dilution. Additionally, any 

analytes detected below the LOQ and above the MDL were reported and qualified “J” as estimated 

values by the laboratory.
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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 implemented 

in accordance with the following approved documents: 

• Final Preliminary Assessment Report, Rickenbacker Army Enclave, Columbus, Ohio dated

March 2019 (AECOM, 2019);

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

Rickenbacker Army Enclave, Columbus, Ohio dated May 2021 (AECOM, 2021a);

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

• Final Site Safety and Health Plan, Rickenbacker Army Enclave, Columbus, Ohio dated June

2021 (AECOM, 2021b).

The SI field activities were conducted from 14 to 16 June and 25 August 2021 and consisted of

utility clearance, direct push boring, soil sample collection, temporary monitoring well installation, 

grab groundwater sample collection, and land surveying. Field activities were conducted in 

accordance with the SI QAPP Addendum (AECOM, 2021a), except as noted in Section 5.8. 

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

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

• Fifteen (15) soil samples from six boring locations;

• Three grab groundwater samples from three temporary well locations;

• Sixteen (16) quality assurance (QA)/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 media. Field documentation is provided in Appendix B. A Log 

of Daily Notice of Field Activity was completed throughout the SI field activities, which is provided 

in Appendix B1. Sampling forms are provided in Appendix B2, Nonconformance and Corrective 

Action Reports are provided in Appendix B3, land survey data are provided in Appendix B4, 

and investigation-derived waste (IDW) logs are provided in Appendix B5. Additionally, a 

photographic log of field activities is provided in Appendix C. 

5.1 Pre-Investigation Activities

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

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

water. Details for each of these activities are presented below.

5.1.1 Technical Project Planning

The USACE TPP Process, Engineer Manual (EM) 200-1-2 (USACE, 2016) defines four phases 

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

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

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

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

identified in the PA. 

A combined TPP Meeting 1 and 2 was held on 16 November 2020 and was conducted in general 

accordance with EM 200-1-2, prior to SI field activities. The stakeholders for this SI include the 
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AECOM 5-2

ARNG, OHARNG, USACE, Ohio EPA, 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 SI QAPP Addendum 

(AECOM, 2021a). 

Future TPP meetings will provide an opportunity to discuss the results and findings, and future 

actions, where warranted. 

5.1.2 Utility Clearance

AECOM’s drilling subcontractor, Cascade Technical Services, LLC, placed a ticket with Ohio811 

“Call Before You Dig” utility clearance provider to notify them of intrusive work on 7 June 2021. 

However, because the RAE is a private facility, the participating “Call Before You Dig” locators did 

not clear utilities at the entire facility. Therefore, AECOM contracted Ground Penetrating Radar 

Services, LLC (GPRS), a private utility location service, to complete the on-facility utility 

clearance. GPRS performed utility clearance of the proposed boring locations on 11 June 2021 

with input from the AECOM field team and RAE facility staff. General locating services and 

ground-penetrating radar were used to complete the clearance. Additionally, the first 5 feet of each 

boring were pre-cleared using a hand auger to verify utility clearance in shallow subsurface soils

where utilities would typically be encountered. 

5.1.3 Source Water and PFAS Sampling Equipment Acceptability

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

acceptable for use in a PFAS investigation prior to the start of field activities. A sample from a 

potable water source at RAE was collected on 5 January 2021, prior to mobilization, and analyzed 

for PFAS by LC/MS/MS compliant with QSM 5.3 Table B-15. The results of the decontamination 

water sample are provided in Appendix F. A discussion of the results is presented in Section 

4.6.3. 

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

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

environment was provided in the Standard Operating Procedures (SOPs) appendix to the SI 

QAPP Addendum (AECOM, 2021a). Prior to the start of field work each day, a PFAS Sampling 

Checklist was completed as an additional layer of control. The checklist served as a daily reminder 

to each field team member regarding the allowable materials within the sampling environment. 

5.2 Soil Borings and Soil Sampling

Soil samples were collected via direct push technology (DPT), in accordance with the SI QAPP 

Addendum (AECOM, 2021a). A GeoProbe® 7822DT dual-tube sampling system was used to 

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

top five feet of the boring, in accordance with AECOM utility clearance procedures. The soil boring 

locations are shown on Figure 5-1 and depths are provided Table 5-1. 

In general, three discrete soil samples were collected from the vadose zone for chemical analysis 

from each soil boring: one surface soil sample (0 to 2 feet bgs), one subsurface soil sample 

approximately 2 feet above the groundwater table, and one subsurface soil sample at the midpoint between the surface and the groundwater table. In borings where groundwater was 

encountered at 6 feet bgs or shallower, only one to two soil samples were collected per boring, in 

accordance with the QAPP Addendum (AECOM, 2021a). Specifically, only two soil samples were 

collected at location RAE-01, and only one soil sample was collected at AOI02-01 due to shallow 

groundwater. 
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AECOM 5-3

The soil cores were continuously logged for lithological descriptions by a field geologist using the 

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

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

and measurements were recorded on sampling forms (Appendix B2) and in a non-treated field 

logbook (i.e., composition notebook). Depth interval, recovery thickness, PID concentrations, 

moisture, relative density, color (using a Munsell soil color chart), and texture (using the USCS) 

were recorded. The boring logs are provided in Appendix E. 

Soil borings completed during the SI found lean clay with sand and fat clay with sand as the 

dominant lithology of the unconsolidated sediments below RAE. The borings were completed at 

depths between 5 and 25 feet bgs. Many of the logs reported varying percentages of gravel and

sand included in the clay layers, with sediment size generally increasing with depth. These facility

observations are consistent with the understood land fill material and glaciofluvial depositional 

environment.

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

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

and transported via Federal Express (FedEx) under standard chain of custody (CoC) procedures 

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

(USEPA Method 9060A) and pH (USEPA Method 9045D) and grain size (ASTM Method D-422) 

in accordance with the SI QAPP Addendum (AECOM, 2021a). 

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

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

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

equipment was used, such as a hand auger for the shallow soil samples, equipment rinsate blanks 

(ERBs) were collected at a rate of 5% and analyzed for the same parameters as the soil samples. 

A temperature blank was placed in each cooler to ensure that samples were preserved at or below 

6 degrees Celsius (°C) during shipment.

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

accordance with the SI QAPP Addendum (AECOM, 2021a) using wetted bentonite chips at 

completion of sampling activities. Borings were installed in grass areas to avoid disturbing 

concrete or asphalt surfaces.

5.3 Temporary Well Installation and Groundwater Grab Sampling

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

the borehole was advanced to the desired depth, wherever conditions allowed, a temporary well 

was constructed of a 5-foot section of 1-inch Schedule 40 poly-vinyl chloride (PVC) screen with 

sufficient casing to reach ground surface. New PVC pipe and screen were used to avoid cross 

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

Table 5-2. 

At proposed temporary monitoring well locations AOI01-01, AOI01-02, and AOI03-02 groundwater 

was not encountered at total boring depths of 20 feet bgs, 20 feet bgs, and 25 feet bgs, 

respectively. After multiple attempts at step-off borings for each location, further boring 

advancement was not advised by ARNG and temporary monitoring wells were not completed at 

these locations. 

Where groundwater was encountered, temporary wells were allowed to recharge after installation 

before collection of groundwater samples. After the recharge period, groundwater samples were 

collected using a peristaltic pump with PFAS-free HDPE tubing. Each sample was collected into 

laboratory-supplied PFAS-free HDPE bottles and labeled using a PFAS-free marker or pen. The 

temporary wells were purged at a rate determined in the field to reduce turbidity and draw down 
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AECOM 5-4

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

dissolved oxygen [DO], and oxidation-reduction potential [ORP]) were measured using a water 

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

collected. Additionally, a subsample of each groundwater sample was collected in a separate 

container, and a shaker test was completed to identify if there were any foaming. No foaming was 

noted in any of the groundwater samples. 

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

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

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

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

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

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

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

accordance with the Programmatic UFP-QAPP (PQAPP) (AECOM, 2018a). A temperature blank 

was placed in each cooler to ensure that samples were preserved at or below 6°C during 

shipment.

Temporary wells were abandoned in accordance with the SI QAPP Addendum (AECOM, 2021a) 

by removing the PVC and backfilling the hole with bentonite chips. Temporary wells were installed 

in grass areas to avoid disturbing concrete or asphalt. 

5.4 Synoptic Water Level Measurements

A synoptic groundwater gauging event was performed on 15-16 June 2021. Groundwater

elevation measurements were collected from the three temporary monitoring wells installed during 

the SI. Water level measurements were taken from the northern side of the well casing. A 

groundwater flow contour map is provided in Figure 2-4. Groundwater elevation data are provided 

in Table 5-2. 

5.5 Surveying 

The northern side of each well casing was surveyed by Ohio-licensed land surveyors following 

guidelines provided in the SOPs provided in the SI QAPP Addendum (AECOM, 2021a). Survey 

data from the newly installed wells on the facility were collected on 16 June 2021 in the applicable 

Universal Transverse Mercator zone projection with World Geodetic System 84 datum (horizontal) 

and North American Vertical Datum 1988 (vertical). The surveyed well data are provided in 

Appendix B4. 

5.6 Investigation-Derived Waste

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

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

was managed in accordance with the SI QAPP Addendum (AECOM, 2021a) and with the DA

Guidance for Addressing Releases of PFAS, Q18 (DA, 2018). 

Soil IDW (i.e., soil cuttings) generated during the SI activities was containerized in one properly 

labeled 55-gallon drum. The soil IDW was not sampled and assumes the PFAS characteristics of 

the associated soil samples collected from that source location. The IDW is currently stored onfacility at a location designated by the OHARNG Environmental Office. ARNG will coordinate 

proper disposal of the solid IDW in accordance with the Army Guidance for Addressing Releases 

of PFAS, Q18 (DA, 2018). 
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AECOM 5-5

Liquid IDW generated during SI activities (i.e. purge water, development water, and 

decontamination fluids) was containerized in one properly-labeled 55-gallon drum (see SOP 3-

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

groundwater samples collected from that source location. The containerized IDW is currently 

stored on-facility at a location designated by OHARNG. Liquid IDW drums were only filled 75% 

full to account for freeze/thaw cycles. ARNG will manage and dispose of the liquid IDW under a 

separate contract in accordance with SOP No. 042A for Treating Liquid Investigation-Derived 

Material (purge water, drilling water, and decontamination fluids) (EA Engineering, Science, and 

Technology, Inc., 2021). ARNG will coordinate proper disposal in accordance with the Army 

Guidance for Addressing Releases of PFAS, Q18 (DA, 2018). The IDW logs describing the 

storage location and relative volume of soil and liquid IDW are documented in Appendix B5. 

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

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

activities were disposed of at a licensed solid waste landfill.

5.7 Laboratory Analytical Methods

Samples were analyzed for a subset of 18 PFAS by LC/MS/MS compliant with QSM 5.3

Table B-15 at Pace Analytical Gulf Coast in Baton Rouge, Louisiana, a DoD ELAP and NELAP 

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

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

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

• N-ethyl perfluorooctanesulfonamidoacetic

acid (NEtFOSAA)

• N-methyl

perfluorooctanesulfonamidoacetic acid

(NMeFOSAA)

• Perfluorobutyrate (PFBA)

• Perfluorobutanesulfonic acid (PFBS)

• Perfluorodecanoic acid (PFDA)

• Perfluorododecanoic acid (PFDoA)

• Perfluoroheptanoic acid (PFHpA)

• Perfluorohexanoic acid (PFHxA)

• Perfluorohexanesulfonic acid (PFHxS)

• Perfluorononanoic acid (PFNA)

• Perfluorooctanoic acid (PFOA)

• Perfluorooctanesulfonic acid (PFOS)

• Perfluoropentanoic acid (PFPeA)

• Perfluorotetradecanoic acid (PFTeDA)

• Perfluorotridecanoic acid (PFTrDA)

• Perfluoroundecanoic acid (PFUdA)

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

9045D. 

5.8 Deviations from SI QAPP Addendum

Three deviations from the SI QAPP Addendum were identified during review of the field 

documentation. These deviations are noted below and are documented in a Field Change 

Request Form (Appendix B3) and Nonconformance and Corrective Action Reports (Appendix 

B4): 

• During the SI utility clearance and field reconnaissance, the field team determined that the

original scoped location for RAE-01 was not located within the property boundary. Upon

discussion with the client group, the sampling location was moved to a location on-facility

that would still meet SI DQOs. This action was documented in a field change request

provided in Appendix B3.
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• During the installation of temporary monitoring wells, three borings (AOI01-01, AOI01-02,

and AOI03-02) were advanced to 20 feet bgs, 20 feet bgs, and 25 feet bgs, respectively,

without encountering groundwater. Multiple attempts at step-off borings were made under

the supervision of the ARNG project manager who was on-facility during the SI field event.

After repeated attempts to reach groundwater, these locations were abandoned since

groundwater could not be collected. This action was documented in a nonconformance and

corrective action report provided in Appendix B4.

• Upon review of field documentation, it was discovered that one surface soil sample, AOI02-

01-SB-0-2, was not collected from the hand auger used to collect the surface soil samples

(0 to 2 feet below ground surface) during the field effort. As a result, the field team remobilized to the facility on 25 August to collect this surface soil sample and shipped it to the

laboratory for analysis. This action was documented in a nonconformance and corrective

action report provided in Appendix B4.
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Sample Identification

Sample

Collection 

Date, Time

Sample Depth 

(feet bgs)

PFAS by LC/MS/MS compliant with QSM 5.3 Table B-15TOC(USEPA Method 9060A)pH (USEPA Method 9045D)Grain Size (ASTM D-422)

Comments

RAE-AOI01-01-SB-0-2 6/15/2021 9:55 0 - 2 x x x

RAE-AOI01-01-SB-0-2-DUP 6/15/2021 10:00 0 - 2 x x FD

RAE-AOI01-01-SB-2-5 6/15/2021 10:05 2 - 5 x x

RAE-AOI01-01-SB-2-5-MS 6/15/2021 10:05 2 - 5 x MS/MSD

RAE-AOI01-01-SB-2-5-MSD 6/15/2021 10:05 2 - 5 x MS/MSD

RAE-AOI01-01-SB-5-7 6/15/2021 10:10 5 - 7 x

RAE-AOI01-02-SB-0-2 6/15/2021 13:30 0 - 2 x

RAE-AOI01-02-SB-8-10 6/15/2021 14:10 8 - 10 x

RAE-AOI01-02-SB-8-10-DUP 6/15/2021 14:12 8 - 10 x FD

RAE-AOI01-02-SB-13-15 6/15/2021 14:15 13 - 15 x x x

RAE-AOI02-01-SB-0-2 8/25/2021 14:10 0 - 2 x

RAE-AOI03-01-SB-0-2 6/15/2021 10:55 0 - 2 x

RAE-AOI03-01-SB-4-6 6/15/2021 11:00 4 - 6 x x

RAE-AOI03-01-SB-8-10 6/15/2021 11:10 8 - 10 x x x

RAE-AOI03-02-SB-0-2 6/15/2021 11:50 0 - 2 x

RAE-AOI03-02-SB-8-10 6/15/2021 12:30 8 - 10 x

RAE-AOI03-02-SB-13-15 6/15/2021 12:35 13 - 15 x

RAE-AOI03-02-SB-13-15-DUP 6/15/2021 12:40 13 - 15 x FD

RAE-01-SB-0-2 6/15/2021 14:30 0 - 2 x x x

RAE-01-SB-0-2-MS 6/15/2021 14:30 0 - 2 MS/MSD

RAE-01-SB-0-2-MSD 6/15/2021 14:30 0 - 2 x x MS/MSD

RAE-01-SB-2-4 6/15/2021 14:45 2 - 4 x x

RAE-01-GW 6/15/2021 12:40 NA x

RAE-AOI02-01-GW 6/16/2021 9:30 NA x

RAE-AOI02-01-GW-DUP 6/16/2021 9:35 NA x FD

RAE-AOI03-01-GW 6/16/2021 12:10 NA x

RAE-AOI03-01-GW-MS 6/16/2021 12:10 NA x MS

RAE-AOI03-01-GW-MSD 6/16/2021 12:10 NA x MSD

Soil Samples

Groundwater Samples

AECOM 5-7
Table 5-1

Site Inspection Samples by Medium

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Sample Identification

Sample

Collection 

Date, Time

Sample Depth 

(feet bgs)

PFAS by LC/MS/MS compliant with QSM 5.3 Table B-15TOC(USEPA Method 9060A)pH (USEPA Method 9045D)Grain Size (ASTM D-422)

Comments

RAE-FRB-01 6/16/2021 10:25 NA x

RAE-FRB-02 8/25/2021 14:05 NA x

RAE-ERB-01 6/15/2021 9:15 NA x from DPT shoe

RAE-ERB-02 6/16/2021 10:00 NA x from DPT shoe

RAE-ERB-03 6/16/2021 10:30 NA x from DPT shoe

RAE-ERB-04 8/25/2021 14:00 NA x from hand auger

Notes:

ASTM = American Society for Testing and Materials

bgs = below ground surface

ERB = equipment rinsate blank

FD = field duplicate

FRB = field reagent blank

LC/MS/MS = Liquid Chromatography Mass Spectrometry

MS/MSD = matrix spike/ matrix spike duplicate

PFAS = per- and polyfluoroalkyl substances

QSM = Quality Systems Manual

RAE = Rickenbacker Army Enclave

TOC = total organic carbon

USEPA = United States Environmental Protection Agency

Quality Control Samples

AECOM 5-8
Table 5-2

Soil Boring Depths, Temporary Well Screen Intervals, and Groundwater Elevations

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Area of 

Interest

Boring 

Location

Soil Boring 

Depth 

(feet bgs)

Temporary Well 

Screen Interval 

(feet bgs)

Top of Casing 

Elevation 

(feet NAVD88)

Ground Surface 

Elevation 

(feet NAVD88)

Depth to 

Water

(feet btoc)

Dep

W

(fee

Upgradient Facility Boundary

RAE-01 5 0 - 5 729.006 724.02 1.33 -3

AOI 2 AOI02-01 10 5 - 10 1 719.96 719.40 5.20 4

AOI 3 AOI03-01 20 10 - 20 1 NA 725.37 NA 7

Notes:

1 Temporary well screen set above total depth to capture groundwater interface

bgs = below ground surfacebtoc = below top of casingNA = not applicableNAVD88 = North American Vertical Datum 1988

AECOM 5-6 

AECOM 
AECOM 

Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

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AOI 1

AOI 2

AOI 3

AOI02-01

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

Legend

!? Soil Boring/Temporary Monitoring Well

!? Soil Boring Location

Area of Interest

Facility Boundary

River/Stream

Surface Water Flow Direction

Localized Groundwater Flow Direction

0 250 500 1,000

Feet

­12420 Milestone Center Drive

Germantown, MD 20876

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REVISED

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NOTES Site Inspection for PFAS at Rickenbacker Army Enclave, OH

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C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Fig_5-1_Rickenbacker_SI_Sample_Locations.mxd

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

Geographics, CNES/Airbus DS, USDA, USGS,

Figure 5-1

Site Inspection Sample Locations

AECOM 5-11
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 5-12

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Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 6-1

6. Site Inspection Results 

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

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

Section 6.3 through Section 6.6. Table 6-2, Table 6-3, and Table 6-4 present PFAS results for 

samples with detections in soil and groundwater; only constituents detected in one or more 

samples are included. Tables that contain all results are provided in Appendix F, and the 

laboratory reports are provided in Appendix D.

6.1 Screening Levels

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

SLs for soil and groundwater, as described in a memorandum from the OSD dated 15 September

2021 (Assistant Secretary of Defense, 2021). The ARNG program under which this SI was 

performed follows this DoD policy. Should the maximum site concentration for sampled media 

exceed the SLs established in the OSD memorandum, the AOI will proceed to the next phase 

under CERCLA. The SLs established in the OSD memorandum apply to three compounds: 

PFOS, PFOA, and PFBS. 

The SLs are presented on Table 6-1 below. All other results presented in this report are 

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

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

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

Analyte

Residential

(Soil)

(μg/kg)a,b

0-2 feet bgs

Industrial/ 

Commercial 

Composite 

Worker

(Soil)

(μg/kg)a,b

2-15 feet bgs

Tap Water

(Groundwater)

(ng/L)a,b

PFOA 130 1,600 40

PFOS 130 1,600 40

PFBS 1,900 25,000 600

Notes:

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

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

September 2021. 

b.) USEPA. 2016a. Drinking Water HA for PFOA. Office of Water (4304T). Health and Ecological Criteria Division, Washington, DC 20460. 

USEPA Document Number: 822-R-16-005. May 2016. / USEPA. 2016b. Drinking Water HA for PFOS. Office of Water (4304T). Health and 

Ecological Criteria Division, Washington, DC 20460. USEPA Document Number: 822-R-16-004. May 2016.

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

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

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

receptors identified at the site: 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.
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 6-2

6.2 Soil Physicochemical Analyses

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

grain size, which are important for evaluating transport through the soil medium. Appendix F

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

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

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

Technology Regulatory Council (ITRC), several important PFAS partitioning mechanisms include 

hydrophobic and lipophobic effects, electrostatic interactions, and interfacial behaviors. At 

relevant environmental pH values, certain PFAS are present as organic anions and are therefore 

relatively mobile in groundwater (Xiao et al., 2015), but 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, which includes 

one potential PFAS release area, the C26 Hangar. The detected compounds in soil are 

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

presented on Figure 6-1 through Figure 6-3.

6.3.1 AOI 1 Soil Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in soil at AOI 1. Soil was sampled at two soil 

boring locations surrounding the C26 Hangar; AOI01-01 and AOI01-02. Three soil samples were 

collected at each AOI 1 boring location: the shallow surface interval (0 to 2 feet bgs), the deep 

interval (5 to 7 feet bgs at AOI01-01 and 13 to 15 feet bgs at AOI01-02), and the intermediate 

interval (2 to 5 feet bgs at AOI01-01 and 8 to 10 feet bgs at AOI01-02). Depths of the intermediate 

and deep soil sample intervals varied between locations depending on the observed depth of 

saturated soil in the boring.

PFOA and PFOS were not detected in soil at AOI 1. PFBS was detected in subsurface soil at 

AOI01-02 in the intermediate sampling interval (8 to 10 feet bgs), at a concentration of 0.023 J 

micrograms per kilogram (μg/kg), several orders of magnitude lower than the SL. PFBS was not 

detected in soil at AOI01-01.

6.3.2 AOI 1 Conclusions

Based on the results of the SI, PFBS was detected in soil at AOI 1; however, the detected 

concentration was several orders of magnitude lower than the soil SL. PFOA and PFOS were not 

detected in soil at AOI 1. Based on these findings, further evaluation of soil at AOI 1 is not 

warranted. No groundwater samples were collected at AOI 1 because groundwater was not 

encountered at soil boring locations AOI01-01 and AOI01-02; temporary monitoring wells were 

not installed at these locations during the SI. Based on these findings, further evaluation of 

groundwater at AOI 1 may be warranted to make site-related remedial decisions.
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 6-3

6.4 AOI 2

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

2, which includes one potential PFAS release area, the drainage ditch. The detected compounds 

in soil and groundwater are summarized on Table 6-2 and Table 6-4. The detections of PFOA, 

PFOS, and PFBS in soil and groundwater are presented on Figure 6-1 through Figure 6-4.

6.4.1 AOI 2 Soil Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in soil at AOI 2. Soil was sampled at one boring 

location, AOI02-01, at the surface interval (0 to 2 feet bgs). AOI02-01 is located adjacent to the 

drainage ditch where stormwater runoff discharged from RAE flows off the facility. No soil samples 

at the subsurface intervals were collected at AOI 2 due to shallow groundwater.

PFBS was the only compound detected in surface soil at AOI02-01, at a concentration of 0.028 J 

μg/kg, which is several orders of magnitude lower than the SL. PFOA and PFOS were not 

detected in surface soil at AOI 2.

6.4.2 AOI 2 Groundwater Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in groundwater at AOI 2. Groundwater samples 

were collected at the temporary well installed at soil boring location AOI02-01, located adjacent 

to the drainage ditch where stormwater runoff discharged from RAE flows off the facility.

PFOA, PFOS and PFBS were detected in groundwater at AOI 2. PFOA and PFOS were detected 

in groundwater, at maximum concentrations of 11.8 nanograms per liter (ng/L) and 13.1 ng/L, 

respectively. PFBS was detected at a maximum concentration of 5.78 ng/L, two orders of 

magnitude lower than the SL.

6.4.3 AOI 2 Conclusions

Based on the results of the SI, PFBS was detected in surface soil at AOI 2; however, the detected

concentration was several orders of magnitude lower than the soil SL. PFOA and PFOS were not 

detected in surface soil at AOI 2. PFOA, PFOS, and PFBS were detected in groundwater at AOI 

2, at concentrations lower than the SLs. Although no PFAS analytes exceeded their respective 

SLs at AOI 2, the shallow depth to groundwater encountered and fat clays observed at location 

AOI02-01 indicate that it is possible groundwater was sampled from a perched water bearing unit. 

Therefore, further evaluation of groundwater at AOI 2 is recommended since there is insufficient 

information to make a remedial decision at this time..

6.5 AOI 3

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

3, which includes one potential PFAS release area, the Helicopter Ramp Area outside of building 

918, where Tri-MaxTM tanks were known to be stored. The detected compounds in soil and 

groundwater are summarized on Table 6-2 through Table 6-4. The detections of PFOA, PFOS, 

and PFBS in soil and groundwater are presented on Figure 6-1 through Figure 6-4.

6.5.1 AOI 3 Soil Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in soil at AOI 3. Soil was sampled at two soil 

boring locations surrounding the Helicopter Ramp Area; AOI03-01 and AOI03-02. Three soil

samples were collected at each AOI 3 boring location: the shallow surface interval (0 to 2 feet 

bgs), the deep interval (8 to 10 feet bgs at AOI03-01, 13 to 15 feet bgs at AOI03-02), and the 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 6-4

intermediate interval (4 to 6 feet bgs at AOI03-01 and 8 to 10 feet bgs at AOI03-02). Depths of 

the intermediate and deep soil sample intervals varied between locations depending on the 

observed depth of saturated soil in the boring.

PFOA was not detected in soil at AOI 3. PFOS was detected in subsurface soil at AOI03-01, at 

the deep interval (8 to 10 feet bgs), at a concentration of 0.136 J μg/kg, which is two orders of 

magnitude lower than the SL. PFBS was detected in shallow subsurface soil at AOI03-01, at the 

intermediate interval (4 to 6 feet bgs), at a concentration of 0.025 J μg/kg, which is several orders 

of magnitude lower than the SL. PFOA, PFOS, and PFBS were not detected in soil at boring 

location AOI03-02 or in surface soil at AOI03-01.

6.5.2 AOI 3 Groundwater Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in groundwater at AOI 3. During the SI, 

groundwater was not encountered at AOI03-02; therefore, a temporary monitoring well was not 

installed. One groundwater sample was collected at the temporary monitoring well installed at soil 

boring location AOI03-01, located adjacent to the Helicopter Ramp Area. PFOA, PFOS and PFBS 

were not detected in groundwater at AOI03-01.

6.5.3 AOI 3 Conclusions

Based on the results of the SI, PFOS and PFBS were detected in soil at AOI 3; however, the 

detected concentrations were at least two orders of magnitude lower than the soil SLs. PFOA, 

PFOS, and PFBS were not detected in groundwater at AOI 3. The facility boundary location, RAE01, had an exceedance of PFOS in groundwater, and although the observed groundwater flow 

direction in onsite wells is to the west, the 2018 BRAC Report for the ANG Base projects 

groundwater to flow southwest across the RAE facility (Aerostar, 2018). If groundwater flow is to 

the southwest, location RAE-01 would be considered downgradient from AOI 3. Due to this 

uncertainty, further evaluation of groundwater at AOI 3 is recommended since there is insufficient 

information to make a remedial decision at this time. .

6.6 Facility Boundary

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

facility boundary location, RAE-01, which is located near the southeastern facility boundary. The 

facility is downgradient of a former ANG FTA on the eastern adjacent ANG property. The detected 

compounds in soil and groundwater are summarized on Table 6-2 through Table 6-4. The 

detections of PFOA, PFOS, and PFBS in soil and groundwater are presented on Figure 6-1

through Figure 6-4.

6.6.1 Facility Boundary Soil Analytical Results

PFOA, PFOS, and PFBS did not exceed the SLs in soil at the facility boundary. Soil was sampled 

at one soil boring location along the southeastern facility boundary, RAE-01. Two soil samples 

were collected at the boring location: the shallow surface interval (0 to 2 feet bgs) and the shallow 

subsurface interval (2 to 4 feet bgs). No deep soil sample was collected at RAE-01 due to shallow 

groundwater.

PFOA, PFOS, and PFBS were detected in soil at RAE-01. PFOA was detected in surface soil, at 

a concentration of 0.282 J μg/kg, which is two orders of magnitude lower than the SL. PFOS and 

PFBS were also detected in surface soil at RAE-01, at concentrations of 1.13 μg/kg and 0.140 J 

μg/kg, respectively. PFOS and PFBS were detected in shallow subsurface soil at RAE-01, at 

concentrations of 0.085 J μg/kg and 0.024 J μg/kg, respectively.
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 6-5

6.6.2 Facility Boundary Groundwater Analytical Results

PFOS in groundwater exceeded the SL at the facility boundary location. Detected concentrations 

of PFOA and PFBS did not exceed their respective SLs for groundwater. Groundwater samples 

were collected from a temporary monitoring well installed at soil boring location RAE-01, located 

near the southeastern facility boundary. 

PFOA, PFOS and PFBS were detected in groundwater at RAE-01. PFOS was detected at a 

concentration of 75.1 ng/L, exceeding the OSD SL of 40 ng/L. PFOA and PFBS were detected at 

concentrations of 13.3 ng/L and 7.34 ng/L, which are below their respective SLs. 

6.6.3 Facility Boundary Conclusions

Based on the results of the SI, PFOA, PFOS, and PFBS were detected in soil at the facility 

boundary; however, the detected concentrations were at least two orders of magnitude lower than 

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

PFOS was detected in groundwater at a concentration exceeding the OSD SL of 40 ng/L. PFOA 

and PFBS were detected in groundwater at concentrations lower than the SLs. Additionally, the 

2018 BRAC Report for the ANG Base indicates that groundwater flows southwest across the 

southern portion of the airport, including the RAE facility (Aerostar, 2018). Although groundwater 

in onsite wells was interpreted as flowing to the west, there is a level of uncertainty with respect 

to the interpreted groundwater flow direction observed in onsite temporary wells. This uncertainty 

will be acknowledged as a data gap that will need to be addressed in the next phase of work. The 

uncertainty presented by the groundwater flow direction in the 2018 BRAC Report indicates that 

location RAE-01 may not be upgradient of facility AOI sampling locations. Based on exceedance 

of the OSD SL for PFOS in groundwater, further evaluation at the facility boundary location is 

recommended.
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 6-6

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Table 6-2

PFAS Detections in Surface Soil

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Analyte OSD Screening 

Level a

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

6:2 FTS - ND ND ND 0.392 J ND ND

PFBA - ND 0.062 J ND ND ND 0.084 JPFBS 1900 ND ND 0.028 J ND ND 0.140 J

PFHpA - ND 0.028 J ND ND ND 0.095 J

PFHxA - ND 0.290 J 0.038 J 0.029 J ND 0.580 J

PFHxS - 0.145 J ND 0.039 J ND ND 4.49

PFNA - ND ND ND ND ND 0.022 J

PFOA 130 ND ND ND ND ND 0.282 J

PFOS 130 ND ND ND ND ND 1.13

PFPeA - ND 0.135 J ND ND ND 0.263 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

6:2 FTS 6:2 fluorot

PFBA perfluorobPFBS perfluorob

References PFHpA perfluoroh

PFHxA perfluorohPFHxS perfluorohPFNA perfluoronPFOA perfluorooPFOS perfluorooPFPeA perfluorop

Interpreted Qualifiers Acronyms and Abbreviations

J = Estimated concentration AOI Area of In

ft feetHQ hazard quLCMSMS liquid chroLOD limit of detND analyte noOSD Office of tQSM Quality SyQual interpreted RAE RickenbacSB soil boringUSEPA United Staμg/kg microgram- not applica

a. Assistant Secretary of Defense, 2021. Risk Based Screening Levels Calculated for PFBS, PFOS, and PFOA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1. 15 September 2021. Soil screening levels based on residential scenario for direct ingestion of contaminated soil.

AOI 1 AOI 3 Upgradient Facility Boundary

RAE-01-SB-0-2

06/14/2021

0 - 2 ft

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

RAE-AOI03-01-SB-0-2

06/15/2021

0 - 2 ft

RAE-AOI03-02-SB-0-2

06/15/2021

0 - 2 ft

RAE-AOI01-02-SB-0-2

06/15/2021

0 - 2 ft

AOI 2

RAE-AOI02-01-SB-0-2

08/25/2021

0 - 2 ft

Area of Interest

Sample ID

Sample Date

Depth

RAE-AOI01-01-SB-0-2

06/15/2021

0 - 2 ft

AECOM 
Table 6-3

PFAS Detections in Shallow Subsurface Soil

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Analyte OSD Screening 

Level a

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

Soil, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)PFBS 25000 ND ND ND UJ 0.023 J ND 0.025 J ND N

PFHxA - ND ND ND ND ND 0.035 J ND N

PFHxS - ND ND 0.039 J ND UJ 0.042 J 0.179 J ND N

PFOS 1600 ND ND ND ND UJ ND ND 0.136 J N

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS pPFHxA pPFHxS p

References PFOA p

PFOS pAcronyms and AbbreviationsAOI ADUP dft fHQ h

Interpreted Qualifiers LCMSMS lJ = Estimated concentration LOD lUJ = The analyte was not detected at a level greater than or equal to the adjusted detection limit (DL). However, the reported adjusted DL is approximate and may be inaccurate or imprecise. ND a

OSD OQSM QQual iRAE RSB sUSEPA Uμg/kg m- n

a. Assistant Secretary of Defense, 2021. Risk Based Screening Levels Calculated for PFBS, PFOS, and PFOA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1. 15 September 2021. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of contaminated soil.

AOI 1 AOI 3

RAE-AOI03-01-SB-4-6

06/15/2021

4 - 6 ft

RAE-AOI03-01-SB-8-10

06/15/2021

8 - 10 ft

RAE-AOI01-02-SB-8-10-DUP

06/15/2021

8 - 10 ft

RAE-AOI01-02-SB-13-15

06/15/2021

13 - 15 ft

RAE-AOI01-01-SB-5-7

06/15/2021

5 - 7 ft

RAE-AOI01-02-SB-8-10

06/15/2021

8 - 10 ft

Area of Interest

Sample ID

Sample Date

Depth

RAE-AOI01-01-SB-2-5

06/15/2021

2 - 5 ft

AECOM 
Table 6-3

PFAS Detections in Shallow Subsurface Soil

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Analyte OSD Screening 

Level a

Result Qual Result Qual Result Qual

Soil, PFAS by LCMSMS compliant with QSM 5.3 Table B-15 (μg/kg)PFBS 25000 ND ND 0.024 JPFHxA - ND ND NDPFHxS - 0.070 J ND UJ 0.039 JPFOS 1600 ND UJ ND 0.085 J

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical Abbreviations

PFBS perfluorPFHxA perfluorPFHxS perfluor

References PFOA perfluor

PFOS perfluorAcronyms and AbbreviationsAOI Area of DUP duplicatft feetHQ hazard q

Interpreted Qualifiers LCMSMS liquid ch

J = Estimated concentration LOD limit of dUJ = The analyte was not detected at a level greater than or equal to the adjusted detection limit (DL). However, the reported adjusted DL is approximate and may be inaccurate or imprecise. ND analyte 

OSD Office oQSM Quality Qual interpretRAE RickenbSB soil boriUSEPA United Sμg/kg microgra- not appl

Area of Interest

Sample ID

Sample Date

Depth

a. Assistant Secretary of Defense, 2021. Risk Based Screening Levels Calculated for PFBS, PFOS, and PFOA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1. 15 September 2021. Soil screening levels based on industrial/commercial composite worker scenario for incidental ingestion of contaminated soil.

RAE-AOI03-02-SB-13-15 DUP

06/15/2021

13 - 15 ft

RAE-AOI03-02-SB-13-15

06/15/2021

13 - 15 ft

Upgradient Facility Boundary

RAE-01-SB-2-4

06/14/2021

2 - 4 ft

AOI 3

AECOM 
Table 6-4

PFAS Detections in Groundwater

Site Inspection Report, Rickenbacker Army Enclave, Ohio

Analyte OSD Screening 

Level a

USEPA HA b Result Qual Result Qual Result Qual Result Qual

6:2 FTS - - 2.58 J ND ND 22.5

8:2 FTS - - ND ND ND 15.9PFBA - - 17.6 13.2 2.49 J 15.0PFBS 600 - 5.78 3.95 J ND 7.34PFHpA - - 4.35 2.79 J ND 5.86PFHxA - - 9.55 5.60 ND 11.9

PFHxS - - 5.35 2.95 J ND 55.5

PFNA - - 2.50 J 1.58 J ND 1.07 J

PFOA 40 70 11.8 6.73 ND 13.3PFOS 40 70 13.1 5.96 ND 75.1PFPeA - - 14.3 10.00 ND 10.1

Total PFOA+PFOS - 70 24.9 12.7 ND 88.4

Grey Fill Detected concentration exceeded OSD Screening Levels Chemical AbbreviationsBold Font Detected concentration exceeded USEPA HA Screening Levels 6:2 FTS 6:2 flu

8:2 FTS 8:2 fluPFBA perfluo

References PFBS perfluo

PFHpA perfluoPFHxA perfluoPFHxS perfluoPFNA perfluoPFOA perfluoPFOS perfluo

Interpreted Qualifiers PFPeA perfluoJ = Estimated concentration

Acronyms and Abbreviations

AOI Area oDUP duplicGW groundHA Health HQ hazard LCMSMS liquid LOD limit oND analytOSD Office QSM QualitQual interprRAE RickenUSEPA United ng/L nanog- not ap

Sample ID

Sample Date

RAE-AOI02-01-GW

06/16/2021

b. USEPA, 2016. Drinking Water Health Advisory for PFOA. Office of Water (4304T). Health and Ecological Criteria Division, Washington, DC 20460. EPA Document Number: 822-R-16-005. May 2016. / EPA. 2016. Drinking Water Health Advisory for PFOS. Office of Water (4304T). Health and Ecological Criteria Division, Washington, DC 20460. EPA Document Number: 822-R-16-004. May 2016.

AOI 2 Upgradient Facility Boundary

RAE-01-GW

06/15/2021

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

a. Assistant Secretary of Defense, 2021. Risk Based Screening Levels Calculated for PFBS, PFOS, and PFOA in Groundwater or Soil using USEPA’s Regional Screening Level Calculator. HQ=0.1. 15 September 2021. Groundwater screening levels based on residential scenario for direct ingestion of groundwater.

RAE-AOI02-01-GW-DUP

06/16/2021

AOI 3

RAE-AOI03-01-GW

06/16/2021

Area of Interest

AECOM 
AOI02-01

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

AOI01-01

AOI03-02

AOI03-01

AOI01-02

Shallow Intermediate Deep

Legend

Facility Boundary

River/Stream ­ Figure 6-1

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Rickenbacker Army Enclave, OH

11/1/2021

11/1/2021

11/1/2021

MS

EG

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

11/1/2021

1:8,400

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Results\Fig_6-1_Rickenbacker_SI_Soil_PFOA_Results.mxd

PFOA Detections in Soil

12420 Milestone Center Drive

0 350 700 1,400 Germantown, MD 20876

Feet

PFOA Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

AECOM 6-11
AOI02-01

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

AOI01-01

AOI03-02

AOI03-01

AOI01-02

Shallow Intermediate Deep

Legend

Facility Boundary

River/Stream ­ Figure 6-2

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Rickenbacker Army Enclave, OH

11/1/2021

11/1/2021

11/1/2021

MS

EG

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

11/1/2021

1:8,400

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Results\Fig_6-2_Rickenbacker_SI_Soil_PFOS_Results.mxd

PFOS Detections in Soil

12420 Milestone Center Drive

0 350 700 1,400 Germantown, MD 20876

Feet

PFOS Results (μg/Kg)

ND

>ND - 10

>10 - 130

>130 - 1,600

>1,600

AECOM 6-12
AOI01-01

AOI03-02

AOI03-01

AOI01-02

AOI02-01

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

PFBS Results (μg/Kg)

ND

>ND - 10

>10 - 1,900

>1,900 - 25,000

>50,000

AOI01-01

RAE-01

AOI03-02

AOI03-01

AOI01-02

Shallow Intermediate Deep

Legend

Facility Boundary

River/Stream ­ Figure 6-3

CLIENT

REVISED

SCALE

PROJECT

ARNG

Site Inspection for PFAS at Rickenbacker Army Enclave, OH

11/1/2021

11/1/2021

11/1/2021

MS

EG

CM

GIS BY

CHK BY

PM

Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

11/1/2021

1:8,400

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Results\Fig_6-3_Rickenbacker_SI_Soil_PFBS_Results.mxd

PFBS Detections in Soil

12420 Milestone Center Drive

0 350 700 1,400 Germantown, MD 20876

Feet

AECOM 6-13
AOI02-01

RAE-01

AOI03-01

PFOA Results (ng/L)

ND

>ND - 10

>10 - 40

>40 - 70

>70 - 400

>400

AOI02-01

RAE-01

AOI03-01

AOI02-01

RAE-01

AOI03-01

Legend

Facility Boundary

River/Stream

Localized Groundwater Flow Direction ­ Figure 6-4

CLIENT

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ARNG

Site Inspection for PFAS at Rickenbacker Army Enclave, OH

4/11/2022

4/11/2022

4/11/2022

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GIS BY

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Base Map: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan,

Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)

4/11/2022

1:8,400

C:\Users\stankevichm\OneDrive - AECOM Directory\ARNG_PFAS_GIS_60552172\MXDs\OH\Rickenbacker_Figures\Rickenbacker_SI_Figures\SI_Report\Results\Fig_6-4_Rickenbacker_SI_GW_Results.mxd

PFOA, PFOS, and PFBS Detections in Groundwater

12420 Milestone Center Drive

0 350 700 1,400 Germantown, MD 20876

Feet

PFOA PFOS PFBS

PFOS Results (ng/L)

ND

>ND - 10

>10 - 40

>40 - 70

>70 - 400

>400

PFBS Results (ng/L)

ND

>ND - 100

>100 - 600

>600 - 1,000

>1,000 - 6,000

>6,000

AECOM 6-14
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 7-1

7. Exposure Pathways

The CSMs for each AOI, revised based on the SI findings, are presented on Figure 7-1 through 

Figure 7-4. A CSM presents the current understanding of the site conditions with respect to known 

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

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

the following conditions are present:

1. Contaminant source;

2. Environmental fate and transport;

3. Exposure point;

4. Exposure route; and

5. Potentially exposed populations.

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

circle symbol to represent an incomplete exposure pathway. Areas with an incomplete pathway 

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

PFOA, PFOS, or PFBS are detected, in which case the CSM figure uses a half-filled circle symbol 

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

is used to indicate when a potentially complete exposure pathway has detections of PFOA, PFOS, 

or PFBS above the SLs. Areas with an identified potentially complete pathway that have detections 

of PFOA, PFOS, and PFBS above the SLs may warrant further investigation.

In general, the potential routes of exposure to PFAS are ingestion and inhalation. Human

exposure via the dermal contact pathway may occur, and current risk practice suggests it is an 

insignificant pathway compared to ingestion; however, exposure data for dermal pathways are 

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

consistent with those listed in USEPA guidance for risk screening (USEPA, 2001). Receptors at 

the facility include site workers (e.g., facility staff and visiting soldiers), construction workers, 

trespassers (thought unlikely due to restricted access), residents outside the facility boundary, 

and recreational users outside of the facility boundary.

7.1 Soil Exposure Pathway

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

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

aforementioned criteria.

7.1.1 AOI 1

Between 2007 and 2008, the C26 Hangar included a fire suppression system with 2.75% Jet-X 

HEF. A test of the system was conducted that involved a release of an unknown amount of Jet-X 

foam from the fire suppression system. All material from the suppression system dissipated into 

the floor drains of the hangar that lead to the sanitary sewer. PFBS was detected in subsurface 

soil at AOI 1 and confirms the release of PFAS to soil.

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

construction worker exposure to PFBS via inhalation or incidental ingestion of subsurface soil. No 

current or ongoing construction is occurring at AOI 1. Additionally, off-facility recreational users

and residents may potentially be exposed to PFBS via inhalation of dust caused by on-facility 

ground disturbing activities, although this exposure is likely insignificant. PFOA, PFOS, and PFBS 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 7-2

were not detected in surface soil at AOI 1; therefore, the site worker, trespasser, off-facility 

recreational user, and resident exposure pathways are considered incomplete. The CSM for AOI 

1 is presented on Figure 7-1. 

7.1.2 AOI 2 

On the southwest corner of the facility is a stormwater drainage ditch, which originates on the 

adjacent OHANG property and enters OHARNG property from the north. Stormwater runoff from 

OHANG hangars and ramp areas are discharged into this ditch, which then flows through 

OHARNG property and exits the property at the northwest facility boundary. Any potential spills 

or discharges on either ramp area or near these drainage channels would eventually flow into the 

stormwater drainage ditch. PFBS was detected in surface soil at AOI 2 and confirms the release 

of PFAS to soil.

Based on the results of the SI at AOI 2, ground-disturbing activities could potentially result in site 

worker, trespasser, and future construction worker exposure to PFBS via inhalation of dust or 

incidental ingestion of surface soil. Additionally, off-facility residents and recreational users may

potentially be exposed to PFBS via inhalation of dust caused by on-facility ground disturbing 

activities, although this exposure is likely insignificant. No current or ongoing construction is 

occurring at AOI 2; however, future construction projects may impact the drainage ditch area. The 

CSM for AOI 2 is presented on Figure 7-2. 

7.1.3 AOI 3 

The Helicopter Ramp Area outside of Building 918 contained between nine to eleven likely PFAScontaining AFFF mobile Tri-MaxTM tanks from approximately 2002 to 2013. It was noted that one 

tank did not properly work and was subsequently emptied of all AFFF, although the emptying date

was not recorded. PFOS and PFBS were detected in subsurface soil at AOI 3 and confirm the 

release of PFAS to soil.

Based on the results of the SI at AOI 3, ground-disturbing activities could potentially result in future 

construction worker exposure to PFOS and PFBS via inhalation of dust or incidental ingestion of 

subsurface soil. No current or ongoing construction is occurring at AOI 3. The CSM for AOI 3 is 

presented on Figure 7-3. 

7.1.4 Facility Boundary

A former ANG FTA is located approximately 5,000 feet east of RAE on the adjacent ANG property

at the Rickenbacker International Airport property. A spill or release from this off-facility source 

has the potential to migrate onto RAE and subsequently impact RAE groundwater. PFOA, PFOS, 

and PFBS were detected in surface soil at the facility boundary and confirm the release of PFAS 

to soil.

Based on the results of the SI at the facility boundary, ground-disturbing activities could potentially 

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

via inhalation of dust and incidental ingestion of surface soil. Additionally, off-facility residents and

recreational users may potentially be exposed to PFOA, PFOS, and PFBS via inhalation of dust 

caused by on-facility ground disturbing activities, although this exposure is likely insignificant. 

PFOS and PFBS were also detected in subsurface soil. Ground-disturbing activities could result 

in future construction worker exposure to PFOS and PFBS via ingestion and inhalation of dust. 

No current or ongoing construction is occurring at the facility boundary. The CSM for the Facility 

Boundary is presented on Figure 7-4. 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 7-3

7.2 Groundwater Exposure Pathway

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

potentially complete pathway exists between the source and potential receptors at AOI 2, AOI 3, 

and the Facility Boundary based on the aforementioned criteria. Due to conflicting information 

regarding groundwater across the airport and the RAE facility, groundwater flow direction is 

considered a data gap that will need to be addressed in future phases of work. 

7.2.1 AOI 2

PFOA, PFOS, and PFBS were detected in groundwater at AOI 2, at concentrations below their 

respective SLs. Although no PFAS analytes exceeded their respective SLs at AOI 2, the shallow 

depth to groundwater encountered and fat clays observed at location AOI02-01 indicate that it is 

possible groundwater was sampled from a perched water bearing unit. Therefore, there is 

insufficient information to evaluate groundwater at AOI 2. Based on available SI sample data for 

AOI 2, the incidental ingestion exposure pathway is considered potentially complete for future 

construction workers during trenching activities deep enough to encounter shallow groundwater. 

Depth to water measured from temporary monitoring wells installed during the SI ranged from 

4.64 to 7.30 feet bgs; therefore, groundwater may be encountered during construction activities. 

RAE is supplied with public water sourced from the City of Columbus public water system; 

therefore, the ingestion exposure pathway for site workers and trespassers is considered 

incomplete. While no potable water wells are located within RAE, potable water wells exist within 

0.5 miles of the facility. Therefore, the ingestion exposure pathway for off-facility residents and 

off-facility recreational users is considered potentially complete. The CSM for AOI 2 is presented 

on Figure 7-2. 

7.2.2 AOI 3

PFOA, PFOS, and PFBS were not detected in groundwater at AOI 3; however, PFOS in 

groundwater exceeded the SL at facility boundary location, RAE-01. Although groundwater in 

onsite wells was interpreted as flowing to the west, there is a level of uncertainty with respect to 

the interpreted groundwater flow direction observed in onsite temporary wells. This uncertainty 

will be acknowledged as a data gap that will need to be addressed in the next phase of work. The 

uncertainty presented by the groundwater flow direction in the 2018 BRAC Report indicates that 

location RAE-01 may not be upgradient of facility AOI sampling locations. Therefore, based on 

the presence of PFOS in groundwater at location RAE-01, there is insufficient information to 

evaluate groundwater at AOI 3.

Based on available SI sample data for AOI 3, the incidental ingestion exposure pathway is 

considered incomplete for construction workers during trenching activities deep enough to 

encounter shallow groundwater. RAE is supplied with public water sourced from the City of 

Columbus public water system; therefore, the site worker and trespasser ingestion pathway are 

considered incomplete. While domestic drinking water wells exist within 0.5 miles of the facility, 

the ingestion exposure pathway for off-facility residents and off-facility recreational users is 

considered incomplete since PFOA, PFOS, and PFBS were non-detect at AOI 3. The CSM for 

AOI 3 is presented on Figure 7-3. 

7.2.3 Facility Boundary

PFOS exceeded the SL in one temporary monitoring well at the facility boundary. PFOA and PFOS 

were detected in groundwater but did not exceed their respective SLs. PFOS detections at 

location RAE-01 indicate that offsite PFAS sources may be contributing to PFAS concentrations 

in environmental media at the facility; however, it is also possible that groundwater flows 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 7-4

southwest across the facility based on the 2018 BRAC Report for the ANG Base. If groundwater 

flows southwest across the facility, then location RAE-01 would be considered downgradient from 

AOI 3. While no potable water wells are located within RAE, domestic drinking water wells exist 

within 0.5 miles of the facility; therefore, the ingestion exposure pathway for off-facility residents 

and recreational users is considered potentially complete. RAE is supplied with public water 

sourced from the City of Columbus public water system; therefore, the site worker and trespasser 

ingestion pathway are considered incomplete. Depth to water measured at RAE-01 during the SI 

was 3.65 feet above ground surface. Therefore, groundwater may be encountered during 

construction activities, and the ingestion exposure pathway for construction workers is considered 

potentially complete. The CSM for the Facility Boundary is presented on Figure 7-4. 

7.3 Surface Water and Sediment Exposure Pathway (Adjacent 

Sources and AOI 2) 

Surface water and sediment samples were not collected at the OHARNG RAE facility during this 

SI; however, surface water and sediment samples were collected on the adjacent OHANG 

property as a part of the 2018 SI for AFFF at the Rickenbacker ANG Base (Aerostar, 2018). Three 

of the OHANG SI surface water and sediment sample locations (RICPSX007, RICPSX008, and 

RICPSX009) exist directly adjacent to the RAE facility. Samples from locations RICPSX007 and 

RICPSX008 were collected from a drainage ditch east of the RAE facility that runs parallel to the 

eastern facility boundary. This drainage ditch conveys runoff southwest before turning northwest 

parallel to the RAE facility’s southwestern boundary. Samples from location RICPSX009 were 

collected from a drainage ditch near the northwest corner of the OHARNG RAE facility. This 

drainage ditch conveys runoff to the southwest, parallel with the RAE facility boundary, before 

turning northwest and ultimately discharges to Big Walnut Creek. Neither of the drainage ditches 

associated with sample locations RICPSX007, RICPSX008 or RICPSW009 traverse the RAE 

facility or drain AOIs at the RAE facility, but they do converge with drainage ditches The 

Rickenbacker ANG Base surface water and sediment samples were not collected from drainage 

ditches within the OHARNG property, but they do converge with drainage ditches draining 

OHARNG AOI areas west of the facility before discharging to Big Walnut Creek (Aerostar, 2018; 

Figure 3-13). 

The maximum concentrations of PFOA, PFOS, and PFBS in sediment samples collected from 

the three adjacent sampling locations are 0.000679 J (estimated concentration) milligrams per 

kilogram (mg/kg), 0.0414 mg/kg, and 0.000233 J mg/kg, respectively. All maximum detected 

concentrations in sediment from the three locations were observed at location RICPSX009, which 

is located near the northwestern corner of the OHARNG RAE facility property. The maximum 

concentrations of PFOA, PFOS, and PFBS in surface water samples collected from the three 

adjacent sampling locations are 0.0182 micrograms per liter (μg/L), 0.182 μg/L, and 0.24 μg/L, 

respectively. All maximum detected concentrations in surface water from the three locations were 

also observed at location RICPSX009 (Aerostar, 2018).

PFAS detections in surface water and sediment in the adjacent ANG Base drainage ditches do 

not represent PFAS migration from OHARNG RAE facility AOIs because the OHANG sample 

locations are not in drainage ditches that drain the OHARNG AOI areas. It is possible; however, 

that PFAS is present in drainage ditches connecting to AOI 2 that were not sampled as a part of 

the 2018 SI for AFFF at the Rickenbacker ANG Base. 

Based on OHANG SI results, the surface water and sediment ingestion exposure pathway for 

OHARNG site workers and construction workers is considered potentially complete. The 

presence of PFAS in surface water and sediment in adjacent drainage ditches also indicates that 

PFAS migration to Big Walnut Creek is possible. Therefore, the surface water and sediment 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 7-5

ingestion exposure pathway for off-facility recreational users of Big Walnut Creek is also 

considered potentially complete. The CSM is presented on Figure 7-2. 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 7-6

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Media

SOURCE PATHWAY RE

AOI 1 Fire Suppression System Test PFAS in Surface Soil

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ Infiltration

Airborne Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Source Release Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

Dust

Incidental 

Ingestion

Incidental 

Ingestion

Incidental 

Ingestion

Incidental 

Ingestion

Hum

C

Flow-Chart ContinuesPartial / Possible FlowFlow-Chart StopsIncomplete PathwayPotentially Complete PathwayComplete Pathway

Site 

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Site 

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Conceptual Si

AOI 1

Rickenbacker Army Enclave 

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Off-Facility 

Source Not 

under 

Control of 

ARNG

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/

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/ 
Media

SOURCE PATHWAY RECEPTOR

AOI 2

Hangar and/or 

Ramp Area 

Discharges; 

Stormwater 

Runoff 

PFAS in 

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or Sediment

Human 

Activities

Precipitation/ 

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Airborne Soil 

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at AOI

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Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

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Human Receptors: 

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Flow-Chart Continues

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Site Worker Construction Worker Resident Trespasser/ Recreational User

Site Worker Construction Worker Resident Trespasser/ Recreational User

/ /

LEGEND

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/

Figure 7-2

Conceptual Site Model

AOI 2 

Rickenbacker Army Enclave Site Inspection Report

Potential 

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Source Not 

under 

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/ /

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/

/

/

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7-8
Media

SOURCE PATHWAY RE

AOI 3 PFAS in Surface Soil

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ Infiltration

Airborne Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Source Release Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

Dust

Incidental 

Ingestion

Incidental 

Ingestion

Incidental 

Ingestion

Incidental 

Ingestion

Hum

C

Flow-Chart ContinuesPartial / Possible FlowFlow-Chart StopsIncomplete PathwayPotentially Complete PathwayComplete Pathway

Site 

Worker

Cons

W

Site 

Worker

Cons

W

LEGEND

/ 

Figure 

Conceptual Si

AOI 3

Rickenbacker Army Enclave 

Potential 

Off-Facility 

Source Not 

under 

Control of 

ARNG

/

Tri-Max Tank 

Disposal 

/

/ 

/ 
Media

SOURCE PATHWAY RE

Upgradient 

Facility 

Boundary

PFAS in 

Surface Soil

Human 

Activities

Precipitation/ 

Run-Off

Leaching/ Infiltration

Airborne Soil 

Particulate

Surface Soil 

at AOI

Surface 

Water/ 

Sediment

Subsurface 

Soil

Shallow 

Groundwater

Source Release Mechanism Media Transport and Migration Media Exposure Routes

Inhalation of 

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Incidental 

Ingestion

Incidental 

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Incidental 

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Flow-Chart ContinuesPartial / Possible FlowFlow-Chart StopsIncomplete PathwayPotentially Complete PathwayComplete Pathway

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Figure 

Conceptual Si

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Rickenbacker Army Enclave 

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Training Area; 

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Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 8-1

8. Summary and Outcome

This section summarizes SI activities and findings. The most significant findings are summarized 

in this section and are reproduced directly or abstracted from information contained in this report. 

The outcome provides general and comparative interpretations of the findings relative to the SLs.

8.1 SI Activities

The SI field activities were conducted between 14 to 16 June 2021 and 25 August 2021, and 

consisted of utility clearance, direct push boring, soil sample collection, temporary monitoring well 

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

conducted in accordance with the SI QAPP Addendum (AECOM, 2021a), except as previously 

noted in Section 5.8.

To fulfill the project DQOs set forth in the approved SI QAPP Addendum (AECOM, 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. The 18 PFAS analyzed as part of the ARNG SI program are specified 

in Section 5.7 of this Report.

• Fifteen (15) soil samples from six boring locations; 

• Three grab groundwater samples from three temporary well locations; 

• Sixteen (16) QA/QC samples

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

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

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

exposure to PFOA, PFOS, and PFBS at the AOIs, which are described in Section 7.

8.2 SI Goals Evaluation

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

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

data collected during this investigation. 

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

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

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

boundary between potential upgradient PFAS release areas and RAE. PFOS in 

groundwater at the Facility Boundary exceeded the SL of 40 ng/L. The detected 

concentrations of PFOA, PFOS, and PFBS in soil samples from all AOIs were below the 

SLs.

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

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

Insufficient information exists for the groundwater pathway at all AOIs, therefore, no AOI 

potential PFAS release areas were removed from further consideration. 

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

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

treatment.
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 8-2

Based on the data collected during this SI, there is not a complete pathway between 

source and on-facility drinking water receptors. Drinking water for RAE is supplied by the 

City of Columbus public drinking water system. Therefore, the exposure pathway to onfacility drinking water receptors is considered incomplete.

There is a potentially complete pathway between source and off-facility drinking water 

receptors. Surficial groundwater at the facility is very shallow, with depth to water ranging 

from approximately 4.6 to 7.3 feet bgs and is therefore not considered a proxy for drinking 

water, since downgradient wells are typically 30 to 200 feet bgs. Refusal encountered 

during the SI field effort at AOI 1 and AOI 3 revealed that there may be a low-permeability 

glacial till confining layer present on-facility; however, it is currently unknown if there is a 

defined confining layer thick enough to prevent vertical PFAS migration. Based on the 

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

downgradient drinking water receptors caused by DoD activities at or adjacent to the 

facility; therefore, a TCRA is not warranted at this time.

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

of a RI (if determined necessary).

The geological data collected as part of the SI indicate a somewhat permeable and 

conductive environment, with soils dominated by clays of varying plasticity and overlain 

by well-graded sand with varying gravel content.

These facility observations are consistent with the known glacial depositional history 

present in the Columbus Lowland district of the Central Lowland physiographic province, 

where RAE is located. The lean and fat clay deposits that dominate the shallow subsurface 

at the facility are representative of the mapped low-permeability, medium-lime 

Wisconsinan-age clay glacial till and outwash unit (ODGS, 1998). Additionally, isolated 

lenses of cobble, coarse and angular gravel observed at thicknesses ranging from 1 to 2 

inches are consistent with regional glacial till and outwash composition (Ohio Department 

of Natural Resources, n.d.). 

Depth to water at RAE measured from 7.30 feet bgs to 3.65 feet above ground surface

(water level measured from temporary monitoring well casing stick-up extending above 

the ground surface at RAE-01). These geologic and hydrogeologic observations inform 

development of technical approach for the RI.

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

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

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

other DoD facilities)

Based upon the evaluation of groundwater and soil results in comparison to SLs, in 

combination with the groundwater flow direction analysis, the results of the SI indicate that 

the source of detected concentrations of PFOA, PFOS, and PFBS at the Site is likely 

attributable to ARNG activities. However, detected concentrations of PFOA, PFOS, and 

PFBS at the facility boundary indicate there may be a potential PFAS source upgradient 

of the facility. It is unclear whether the facility boundary location is upgradient from AOIs 

based on the southwestern groundwater flow direction presented in the 2018 BRAC 

Report for the ANG Base. 

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

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

Detections of PFOS and PFBS in soil and PFOA, PFOS, and PFBS in groundwater at 

source areas and the facility boundary indicate there is a potentially complete pathway 

between source and site workers, future construction workers, and trespassers. The 
Final Site Inspection Report

Rickenbacker Army Enclave, Columbus, OH

AECOM 8-3

PFOS SL exceedance in surficial groundwater indicates there is a potentially complete 

exposure pathway between source and future construction workers, as well as off-facility 

drinking water receptors.

8.3 Outcome 

Based on the CSMs developed and revised in light of the SI findings, there is potential for 

exposure from sources on facility resulting from historical DoD activities. Sample analytical 

concentrations collected during the SI were compared against the project SLs for PFOA, PFOS, 

and PFBS in soil and groundwater, as described in Table 6-1. A summary of the results of the SI 

data relative to the SLs is as follows:

• At AOI 1, refusal was encountered, and groundwater was unable to be sampled at the 

C26 Hangar potential PFAS release area. Based on the results of the SI, further evaluation 

of groundwater at AOI 1 is recommended to make site-related remedial decisions.

• At AOI 2, PFOA, PFOS, and PFBS were detected in groundwater at the Drainage Ditch 

potential PFAS release area below the OSD SLs. Although no PFAS analytes exceeded 

their respective SLs at AOI 2, the shallow depth to groundwater encountered and fat clays 

observed at location AOI02-01 indicate that it is possible groundwater was sampled from 

a perched water bearing unit. Therefore, there is insufficient information to make a 

remedial decision and further evaluation of groundwater at AOI 2 is recommended.

• At AOI 3, PFOS, PFOA, and PFBS were non-detect in groundwater at the Helicopter 

Ramp Area potential PFAS release area; however, PFOS in groundwater exceeded the 

SL at facility boundary location, RAE-01. Although the groundwater flow direction 

observed in onsite temporary wells was to the west, a 2018 Base Realignment and 

Closure (BRAC) Report for the Rickenbacker Air National Guard (ANG) Base projects that 

groundwater across the southern portion of the airport flows southwest (Aerostar, 2018). 

If groundwater flows southwest across the eastern portion of the RAE, temporary well 

location RAE-01 may be considered downgradient of AOI 3. Therefore, based on the 

presence of PFOS in groundwater at location RAE-01, there is insufficient information to 

make a remedial decision and further evaluation of groundwater at AOI 3 is recommended. 

• At the Facility Boundary location, RAE-01, PFOS was detected in exceedance of the OSD 

SL at 75.1 nanograms per liter (ng/L), and PFOA was detected at 13.3 ng/L. PFOS

detections at location RAE-01 indicate that offsite PFAS sources may be contributing to 

PFAS concentrations in environmental media at the facility; however, it is also possible 

that groundwater flows southwest across the facility based on the 2018 BRAC Report for 

the ANG Base. If groundwater flows southwest across the facility, then location RAE-01 

would be considered downgradient from AOI 3. Due to this uncertainty and the 

concentrations of PFOS in groundwater at location RAE-01 exceeding the SL, further 

evaluation of the Facility Boundary is recommended.

• The detected concentrations of PFOA, PFOS, and PFBS in soil at all AOIs were below the 

SLs. 

Table 8-1 summarizes the SI results for soil and groundwater. Based on the CSMs developed 

and revised in light of the SI findings, there is potential for exposure to drinking water receptors 

caused by DoD activities at or adjacent to the facility.

Table 8-2 summarizes the rationale used to determine if an AOI should be considered for further 

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

information is required to make remedial decisions for all AOIs at this facility.
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Table 8-1: Summary of Site Inspection Findings

AOI Potential PFAS 

Release Area

Soil –

Source Area

Groundwater –

Source Area

Groundwater –

Facility Boundary

1 C26 Hangar N/A(1) N/A

2 Drainage Ditch

3 Helicopter Ramp Area

Facility 

Boundary

Off-Facility/ 

Upgradient

Legend:

N/A = Not applicable 

(1) Groundwater was not encountered at AOI 1; therefore, groundwater samples could not be collected.

= PFOA, PFOS, and/ or PFBS detected; exceedance of the screening levels

= PFOA, PFOS, and/ or PFBS detected; no exceedance of the screening levels

= PFOA, PFOS, and PFBS not detected

Table 8-2: Site Inspection Recommendations

AOI Description Rationale Future Action

1 C26 Hangar

Unable to collect 

groundwater samples. No 

exceedances of SLs in soil. 

Consider further groundwater 

evaluation.

2 Drainage Ditch

Detections in groundwater 

at potential source area. 

Additionally, groundwater 

samples collected could 

possibly represent perched 

water, not water table. No 

exceedances of SLs in soil. 

Consider further groundwater 

evaluation.

3 Helicopter Ramp 

Area

No detections in 

groundwater; however, 

exceedances are present in 

potential downgradient 

sample location. No 

exceedances of SLs in soil.

Consider further groundwater 

evaluation.

Facility 

Boundary 

Off-Facility/ 

Upgradient

Exceedances of SL in 

groundwater at source 

area. No exceedances of 

SLs in soil.

Consider further groundwater 

evaluation.
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AECOM 9-1

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