FINAL

Preliminary Assessment Report

Wilmington Readiness Center,

Wilmington, Delaware

Perfluorooctanesulfonic Acid (PFOS) and Perfluorooctanoic 

Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

June 2020

Prepared for:

Army National Guard Bureau

111 S. George Mason Drive

Arlington, VA 22204

UNCLASSIFIED
PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wimington, Delaware

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Table of Contents

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

1. Introduction ........................................................................................................................3

Authority and Purpose ..............................................................................................3

Preliminary Assessment Methods .............................................................................3

Report Organization ..................................................................................................4

Facility Location and Description...............................................................................4

Facility Environmental Setting ...................................................................................4

1.5.1 Geology .........................................................................................................5

1.5.2 Hydrogeology .................................................................................................5

1.5.3 Hydrology .......................................................................................................5

1.5.4 Climate ...........................................................................................................6

1.5.5 Current and Future Land Use .........................................................................6

2. Fire Training Areas ...........................................................................................................10

3. Non-Fire Training Areas ...................................................................................................11

4. Emergency Response Areas ............................................................................................12

5. Adjacent Sources .............................................................................................................13

Air National Guard Base .........................................................................................13

6. Preliminary Conceptual Site Model ..................................................................................15

7. Conclusions .....................................................................................................................16

Findings ..................................................................................................................16

Uncertainties ...........................................................................................................16

Potential Future Actions ..........................................................................................17

8. References ......................................................................................................................19

Figures

Figure ES-1 Summary of Findings

Figure 1-1 Facility Location

Figure 1-2 Groundwater Features

Figure 1-3 Surface Water Features

Figure 7-1 Summary of Findings

Tables

Table 7-1 Uncertainties

Appendices

Appendix A Data Resources

Appendix B Preliminary Assessment Documentation

B.1 Interview Records

B.2 Visual Site Inspection Checklists

B.3 Conceptual Site Model Information

Appendix C Photographic Log
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Wimington, Delaware

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Acronyms and Abbreviations

°F Degrees Fahrenheit

μg/L micrograms per liter

AECOM AECOM Technical Services, Inc.

AFFF Aqueous Film Forming Foam

AOI Area of Interest

amsl Above Mean Sea Level

AFW Amec Foster Wheeler

ANGB Air National Guard Base

ARNG Army National Guard

CERCLA Comprehensive Environmental Response, Compensation, and Liability

Act

CFR Code of Federal Regulations

CSM Conceptual Site Model

DEARNG Delaware Army National Guard

DGS Delaware Geological Survey

DNREC Delaware Department of Natural Resources and Environmental Control

DRBC Delaware River Basin Commission

EDRTM Environmental Data Resources, Inc.TM

FTA Fire Training Area

gpm gallons per minute

HA Health Advisory

IED Installations & Environment Division

NCCDE New Castle County Delaware Government

PA Preliminary Assessment

PFAS Per- and Poly-Fluoroalkyl Substances

PFOA Perfluorooctanoic Acid

PFOS Perfluorooctanesulfonic Acid

SI Site Inspection

UCMR3 Unregulated Contaminant Monitoring Rule 3

US United States

USACE United States Army Corps of Engineers

USEPA United States Environmental Protection Agency

VSI visual site inspection
PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

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Executive Summary

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

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

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

(PFAS)-containing materials was completed for Wilmington Readiness Center (also referred to as

the “facility”) in Wilmington, Delaware, to assess potential PFAS release areas and exposure

pathways to receptors. Wilmington Readiness Center is constructed on a parcel of land deeded

to the State of Delaware through the Red Clay Creek Consolidation School District. The deed was

signed in 1992 and is effective indefinitely.

The performance of this PA included the following tasks:

· Reviewed available administrative record documents and Environmental Data Resources,

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

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

environmental compliance actions in the area surrounding the facility;

· Conducted a site visit on 6 August 2019 and completed visual site inspections (VSIs) at

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

disposed;

· Interviewed current Wilmington Readiness Center and Delaware ARNG personnel, including

environmental managers and operations staff during the site visit; 

· Identified Areas of Interest (AOIs) and developed a preliminary conceptual site model to

summarize potential PFAS source-pathway-receptor linkages for each AOI.

No AOIs related to potential PFAS use, release, or storage were identified at Wilmington

Readiness Center during the PA (Figure ES-1). One potential adjacent source of PFAS was

identified downgradient of the facility. Based on facility history and interviews with various

personnel, there is no potential for exposure to PFAS contamination in media at or near the facility.

Based on the US Environmental Protection Agency’s (USEPA) Unregulated Contaminant

Monitoring Rule 3 (UCMR3) data, it was indicated that PFAS were detected in a public water

system above the USEPA’s lifetime Health Advisory (HAs) within 20 miles of the facility (Appendix

A). PFAS analyses performed in 2016 had method detection limits that were higher than currently

achievable. Thus, it is possible that low concentrations of PFAS were not detected during the

UCMR3 but might be detected if analyzed today.
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Summary of Findings

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Wilmington, Delaware

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1. Introduction

Authority and Purpose

The Army National Guard (ARNG)-Installations & Environment Division (IED) is the lead agency 

in performing Preliminary Assessments (PAs) and Site Inspections (SIs) for 

Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) at Impacted Sites at 

ARNG Facilities Nationwide. This work is supported by the United States (US) Army Corps of 

Engineers (USACE) Baltimore District and their contractor AECOM Technical Services, Inc. 

(AECOM) under Contract Number W912DR-12-D-0014, Task Order W912DR17F0192, issued 11 

August 2017.

The ARNG is assessing potential effects on human health related to processes at facilities that 

used per- and poly-fluoroalkyl substances (PFAS), primarily in the form of aqueous film forming 

foam (AFFF) released as part of firefighting activities, although other PFAS sources are possible. 

In addition, the ARNG is assessing businesses or operations adjacent to the ARNG facility (not 

under the control of ARNG) that could potentially be responsible for a PFAS release. 

PFAS are classified as emerging environmental contaminants that are garnering increasing 

regulatory interest due to their potential risks to human health and the environment. PFAS 

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

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

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

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

national standards regulating PFAS in drinking water.

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

Center (also referred to as the “facility”) in Wilmington, Delaware, in accordance with the 

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

amended, the National Oil and Hazardous Substances Pollution Contingency Plan (40 Code of 

Federal Regulations [CFR] Part 300), and USACE requirements and guidance. 

This PA documents potential locations where PFAS may have been released into the environment 

at Wilmington Readiness Center. The term PFAS will be used throughout this report to encompass 

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

AFFF.

Preliminary Assessment Methods

The performance of this PA included the following tasks: 

· Reviewed available administrative record documents and Environmental Data Resources, 

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

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

environmental compliance actions in the area surrounding the facility;

· Conducted a site visit on 6 August 2019 and completed visual site inspections (VSIs) at 

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

disposed;

· Interviewed current Wilmington Readiness Center and Delaware ARNG (DEARNG), 

personnel including environmental managers and operations staff during the site visit; 

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

to summarize potential PFAS source-pathway-receptor linkages for each AOI.
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Wilmington, Delaware

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Report Organization

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

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

each are as follows:

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

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

· Section 2 – Fire Training Areas: describes the fire training areas (FTAs) at the facility 

identified during the site visit. 

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

at the facility identified during the site visit. 

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

facility, specifically in response to emergency situations. 

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

facility that are not under the control of ARNG. 

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

and receptors for the AOIs and the facility. 

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

uncertainties of the PA. 

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

· Appendix A – Data Resources

· Appendix B – Preliminary Assessment Documentation

· Appendix C – Photographic Log

Facility Location and Description

Wilmington Readiness Center occupies approximately 4.5 acres in Wilmington, Delaware and 

served as the Delaware National Guard Headquarters from 1982 to 2014 (Figure 1-1). The facility 

is located at the former Laura Little Elementary School near Delcastle Recreational Park. 

Wilmington Readiness Center is co-located with the Mid-County Senior Center and is home to 

the Delaware Military Museum. Properties surrounding Wilmington Readiness Center are 

primarily zoned for single-family homes (New Castle County Delaware Government [NCCDE], 

2018). The facility operates under a deed enacted in 1992 between the Red Clay Creek 

Consolidation School District and the State of Delaware. 

Wilmington Readiness Center has been used as the Delaware National Guard Headquarters for 

both Army and Air National Guards. The facility includes three connected buildings that comprise 

the former elementary school, two parking lots, a paved storage area, and a shed used for storage 

by the Delaware Emergency Management Agency. Currently, the facility is used for administrative 

activities. 

Facility Environmental Setting

The facility is located in northern New Castle County, Delaware. Major geographic features 

include the Christina River, which flows generally northeast, into the Delaware River, and is part 

of the Christina River Basin reaching into Pennsylvania (Delaware Watersheds, n.d.). The 

Delaware River flows south to the Delaware Bay. Buildings, asphalt, and concrete cover much of 
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the facility, but a large empty field lies in the northern area of the property. Wilmington Readiness

Center lies within the Coastal Plain region of Delaware and is a predominantly low, flat area about

100 feet above mean sea level (amsl) (Figure 1-2).

1.5.1 Geology

The facility is underlain by the Wissahickon Formation, near the contact with the Faulkland

Gneiss. The Cambrian to Ordovician Wissahickon Formation is characterized as interlayered

psammitic and pelitic gneiss with amphibolite. Quaternary alluvial deposits composed of sand,

silt, clay, and gravel are located to the west of the facility, along Mill Creek (Ramsey, 2005).

The Ordovician-aged Faulkland Gneiss is a member of the Wilmington Complex and is

composed of predominantly fine- to coarse-grained amphibolites and quartz amphibolites with

minor felsic rocks. The geology of the site is shown in Figure 1-2.

1.5.2 Hydrogeology

At the facility, groundwater flow is influenced by the underlying bedrock and is controlled by the

bedrock topography and permeability of the bedrock itself. Permeability is determined by the

density of fractures and joints and the degree of weathering. A study in the Red Creek Basin,

located adjacent to the facility, noted that the water table is located in the saprolite (weathered

bedrock) and acts as an unconfined aquifer (Vogel and Reif, 1993). Groundwater yields from initial

pump tests in the crystalline Piedmont rocks range from no yield to up to 500 gallons per minute

(gpm). Typically, the higher yields are associated with the Cockeysville Marble, and the lower

yields are associated with the Wilmington Complex (Woodruff, 1977) (Figure 1-3). Groundwater

is inferred to flow to the southeast.

In New Castle County, south of the Chesapeake and Delaware Canal and approximately 13 miles

south of the facility, nearly all drinking water is supplied from groundwater provided by public and

private wells. However, north of the canal, in northern New Castle County, groundwater supplies

only 30 percent of drinking water (Delaware Geological Survey [DGS], 2019).

Based on the USEPA Unregulated Contaminant Monitoring Rule 3 (UCMR3) data, it was indicated

that PFAS were detected in a public water system above the HA within 20 miles of the facility

(Appendix A). PFAS analyses performed in 2016 had method detection limits that were higher

than currently achievable. Thus, it is possible that low concentrations of PFAS were not detected

during the UCMR3 but might be detected if analyzed today. The Delaware Department of Natural

Resources and Environmental Control (DNREC) reported that Artesian Water Company, a

primary drinking water provider in the area, and the City of New Castle Municipal Services

Commission detected PFAS above the HA in public water supply wells in the area of Wilmington

Readiness Center. According to the New Castle County Airport Area Community Fact Sheet

provided in Appendix A, the area of contamination is southeast of the facility and is approximately

7 square miles around the New Castle County Airport. The contamination area is bounded to the

north by Interstate 295, the Delaware River to the east, Route 273 to the south, and Route 13 and

New Castle Airport to the west. The public water supply is treated for PFAS contamination before

distribution (DNREC, 2019). There are private domestic supply wells within 1 mile of the facility

to the northwest and southeast (EDRTM, 2019).

1.5.3 Hydrology

South of Wilmington Readiness Center is the Christina River, a part of the Christina River Basin

that extends from Pennsylvania through New Castle County, Delaware. The Christina River Basin

is characterized by dendritic interconnected rivers, streams, and wetlands, with outflow to the

Delaware River. The Christina River is in the southernmost area of the basin and flows northeast,
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into the Delaware River. Surface water accounts for 70 percent of New Castle County’s water

supply, the majority of which comes from the Christina River Basin, which provides 60 percent of

New Castle County’s water overall (NCCDE, 2018). The majority of Christina River is in New

Castle County, with headwaters in Maryland. The Christina River is tidal from just south of the

Town of Christiana to its convergence with the Delaware River. This section of the Christina lies

approximately 3.3 miles southeast of the facility, and tidal freshwater wetlands occur by the river

(Delaware Watersheds, n.d.).

Wilmington Readiness Center sits primarily on the Lower White Clay Creek Watershed, with the

southeastern corner in the Red Clay Creek Watershed. Surrounding the facility, general surface

water flow is southeast via Mill Creek. Mill creek flows to White Clay Creek, which converges

downstream with the Christina and continues northeast to the Delaware River.

The facility is approximately 7.5 miles west of the Delaware River and is closest to the River’s 68-

mile marker (Delaware River Basin Commission [DRBC], 2011). A presentation from the DRBC

provides 2009 PFAS concentration data for media tested along the Delaware river. PFAS were

detected in surface water in the section closest to the facility, between river miles 68 and 70

(DRBC, 2012). The 2009 PFOA concentration at river mile 68.1 was 0.0277 micrograms per liter

(μg/L), and the PFOS concentration was 0.00575 μg/L (DRBC, 2012).

1.5.4 Climate

The climate at Wilmington Readiness Center is humid continental. The Delaware Bay and Atlantic

Ocean to the east and south, and the Chesapeake Bay to the west moderate temperature

extremes in the winter and summer months. Although the extremes are moderated, the climate

at Wilmington Readiness Center is still continental, with hot summers, cold winters, and

precipitation throughout the year (Amec Foster Wheeler [AFW], 2019). Mean annual temperature

in New Castle is 54 degrees Fahrenheit (°F). The average annual high temperature for

Wilmington, Delaware is 64.1°F, and the average annual low temperature is 45.8°F. Annual

precipitation for Wilmington is approximately 43 inches of rain and 19 inches of snowfall (US

Climate Data, 2019).

1.5.5 Current and Future Land Use

Wilmington Readiness Center currently resides on a portion of land deeded to the DEARNG in

1992 from the Red Clay Creek Consolidation School District; it was the DEARNG headquarters

from 1982 until 2014. The facility is currently used for administrative activities and houses the

Delaware Military Museum. Wings A and B of the building will be demolished in the future;

however, DEARNG activities at the facility are not anticipated to change
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Facility Location

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

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

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Groundwater Features

Base Map: Source: Esri, DigitalGlobe, GeoEye,

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Geology

Potomac Formation

Grantitic Pegmatite

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Surface Water Features

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2. Fire Training Areas

Based on interviewee knowledge of Wilmington Readiness Center history, no FTAs were identified

during this PA. Interviewee knowledge for this facility dates back to 1995, 3 years after DEARNG

signed a deed taking possession of the property. All information obtained regarding activities at

the property from 1982 to 1995 was received secondhand from interviewees.
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3. Non-Fire Training Areas

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

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

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

features obtained during the PA are included in Appendices A and B. No non-FTA areas where

AFFF was potentially stored, used, or released were identified during the PA through interviews

or historical document review.
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4. Emergency Response Areas

No emergency response areas were identified within the facility during the PA through interviews

or Environmental Data Resource Reports. The City of Wilmington Fire Department would handle

any potential fire or emergency response incident at Wilmington Readiness Center.
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5. Adjacent Sources

One potential off-facility source of PFAS located adjacent to Wilmington Readiness Center, not 

under the control of ARNG, was identified during the PA through interviews and historical 

document review. 

Air National Guard Base

The nearby Air National Guard Base (ANGB), located approximately 4.8 miles southeast of the 

facility and shown in Figure 5-1, has undergone an SI for PFAS. Results of the study show HA 

exceedances for PFAS in groundwater and detections in a surface water sample (AFW, 2019). 

Of the groundwater sample locations, eight locations had results above the HA, and one of two 

surface water sample locations had a combined PFOS and PFOA detection of 0.4247 μg/L (AFW, 

2019). Due to the ANGB’s downgradient location, contamination at the base is not believed to 

influence Wilmington Readiness Center. 
ANGB

Army Creek

Pike

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C hestnut Run

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Adjacent Sources

Base Map: Source: Esri, DigitalGlobe, GeoEye,

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6. Preliminary Conceptual Site Model

Based on the PA findings from interviews with facility personnel, on-facility observations, review

of EDRTM reports, and online research, no release areas were identified as AOIs at Wilmington

Readiness Center. A CSM identifies three components necessary for potentially complete

exposure pathways related to a site: (1) source, (2) pathway, and (3) receptor. If any of these

elements are missing, the pathway is considered incomplete. However, since no PFAS sources

were identified to originate at Wilmington Readiness Center or from activities associated with the

facility, CSMs were not developed.
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7. Conclusions

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

AFFF at Wilmington Readiness Center. The PA findings are based on the information presented 

in Appendix A and from interview records.

Findings

Based on information obtained during interviews conducted with facility personnel, facility 

observations, and reviewed documentation, it is confirmed that AFFF has not been stored, used, 

or released at Wilmington Readiness Center; therefore, no AOIs related to PFAS release were 

identified at Wilmington Readiness Center. 

Interviewee knowledge from DEARNG personnel at the Wilmington Readiness Center and other 

DEARNG facilities dates back to at least 1995. Evidence obtained during the PA supports that 

current or former ARNG facility activities have not contributed to any potential PFAS 

contamination in media at or near the facility. No potential areas of PFAS use, release, or storage, 

current or historic, were identified at Wilmington Readiness Center. One potential adjacent source 

of PFAS was identified downgradient of the facility during the PA.

Uncertainties

A number of information sources were investigated during this PA to determine the potential for 

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

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

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

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

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

environmental reports, EDRsTM, observations made during the VSI, and interviews. Interviews of 

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

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

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

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

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

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

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

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

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

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

interviewed for the same potential source area, and potential source areas were visually 

inspected. Table 7-3 summarizes the uncertainties associated with the PA.

Table 7-1 Uncertainties

Area of Interest Source of Uncertainty

Wilmington 

Readiness Center

Interviewee knowledge for this facility dates back to at least 1995; 

however, a data gap exists between 1982 and 1995. Information 

received regarding this time period was from secondhand knowledge. 
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Potential Future Actions

Based on the absence (1982-present) of the use, storage, or release of PFAS-containing 

materials at Wilmington Readiness Center, no AOIs were identified during the PA. Evidence does 

not indicate that current or former ARNG activities contributed PFAS contamination to media at 

or near the facility. Wilmington Readiness Center will not move forward in the CERCLA process. 
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Summary of Findings

Base Map: Source: Esri, DigitalGlobe, GeoEye,

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

C:\Users\samir.khadka\AECOM Directory\Stankevich, Michael - ARNG_PFAS_GIS_60552172\MXDs\DE\Wilmington_Readiness_Center\Fig_7-1_Wilmington_Summary.mxd

Legend

Facility Boundary

Water Body

River/Stream

0 500 1,000 2,000

Feet

Preliminary Assessment for PFAS at Wilmington Readiness Center, DE

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Wilmington Readiness Center

Wilmington, Delaware

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8. References

Amec Foster Wheeler (AFW). 2019. Final Report FY16 Phase 1 Regional Site Inspections for

Per and Poly Fluoralkyl Substances Volume I of XII.

Delaware Department of Natural Resources and Environmental Control (DNREC). New Castle

County Airport Area Community Fact Sheet. (Accessed September 2019).

http://www.dnrec.delaware.gov/dwhs/SIRB/Documents.

Delaware Geological Survey (DGS). 2019. Hydrologic Information for Delaware. (Accessed

September 2019). https://www.dgs.udel.edu/water-resources.

Delaware River Basin Commission (DRBC). 2012. Contaminants of Emerging Concern in the

Tidal Delaware River. (Accessed November 1, 2019).

https://www.nj.gov/drbc/library/documents/contaminants-of-emergingconcernAug2013rev.pdf.

Delaware River Basin Commission (DRBC). 2011. River Mileage System. (Accessed November

11, 2019). https://www.state.nj.us/drbc/basin/river/.

Delaware Watersheds. Christina River. (Accessed August 2019).

http://delawarewatersheds.org/piedmont/christina-river/.

Environmental Data Resources (EDR) TM, 2019. The EDRTM Radius Map Report with

GeoCheck.

New Castle County Delaware Government (NCCDE). 2018. Zoning Map Index. (Accessed

September 2019). http://zoningmaps.nccde.org/.

Ramsey, Kelvin W. 2005. Geologic Map of New Castle County, Delaware.

Vogel, K.L., and Reif, A.G. 1993. Geohydrology and Simulation of Ground-Water Flow in the

Red Clay Creek Basin, Chester County, Pennsylvania, and New Castle County, Delaware.

United States Geological Survey. Water-Resources Investigations Report 93-4055.

Woodruff, Kenneth D. 1977. Geohydrology of the Newark Area, Delaware. Delaware Geological

Society. Hydrologic Map Series No. 2.

U.S. Climate Data. 2019. Climate Wilmington – Delaware. (Accessed August 2019).

https://www.usclimatedata.com/climate/wilmington/delaware/united-states/usde0055.

U.S. Environmental Protection Agency (USEPA), 1991. Guidance for Performing Preliminary

Assessments under CERCLA. EPA/540/G91/013.
PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

Appendix A

Data Resources
Data Resources will be provided separately on CD. Data Resources for Wilmington Armory

include:

Wilmington Previous Site Investigations

· 2019, Final Report FY16 Phase 1 Regional Site Inspections for Perfluorinated

Compounds, Amec Foster Wheeler

· Delaware Department of Natural Resources and Environmental Control’s New Castle

County Airport Area Fact Sheet, PFOS/PFOA Detected in Ground Water from New

Castle Public Wells

Wilmington Site Background Documents

· 1977, Geohydrology of the Newark Area, Delaware, Kenneth D. Woodruff

· 1993, Altitude and Configuration of the Simulated Water-Level Surface of the Aquifer in

the Red Clay Creek Basin

· 1993, Geohydrology and Simulation of Ground-Water Flow in the Red Clay Creek Basin,

Chester County, Pennsylvania, and New Castle County, Delaware, Karen L. Vogel and

Andrew G. Reif

· 1993, Geologic Map of the Red Clay Creek Basin and Location of Wells and Base-Flow

Measurement Sites, Karen L. Vogel and Andrew G. Reif

· 2005, USGS Geologic Map of New Castle County, Delaware, Kelvin W. Ramsey

· 2013, Contaminants of Emerging Concern in the Tidal Delaware River: Pilot Monitoring

Survey 2007-2009

· UCMR 3 Data

Wilmington Site Property Documents

· 1992, Wilmington Armory Deed, March 10

Environmental Data Resources, Inc.TM Reports

· 2019, Aerial Photo Decade Package, Environmental Data Resources, Inc.TM

· 2019, Certified Sanborn Map Report, Environmental Data Resources, Inc.TM

· 2019, Radius Map Report with Geocheck, Environmental Data Resources, Inc.TM

· 2019, Wilmington Historical Aerials, Environmental Data Resources, Inc.TM
PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

Appendix B

Preliminary Assessment Documentation
PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

Appendix B.1

Interview Records

PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

Appendix B.2

Visual Site Inspection Checklists



PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

Appendix B.3

Conceptual Site Model Information



PFAS Preliminary Assessment Report

Wilmington Readiness Center

Wilmington, Delaware

Appendix C

Photographic Log
Preliminary Assessment Report 

Wilmington Readiness Center

Perfluorooctane-Sulfonic Acid (PFOS) and 

Perfluorooctanoic Acid (PFOA) Impacted Sites

ARNG Installations, Nationwide

APPENDIX C – Photographic Log

Army National Guard, Preliminary 

Assessment for PFAS Wilmington Readiness Center Wilmington, Delaware

Photograph No. 1

Description:

AB fire extinguisher mounted 

on the wall inside the facility.

Photo Date: 8/5/2019 

Photograph No. 2

Description:

Tag from the AB fire 

extinguisher above. This is the 

only type of extinguisher at 

the facility.

Photo Date: 8/5/2019