ORIGINAL SEMS DocID 2298711 FOURTH EXPLANATION OF SIGNIFICANT DIFFERENCES for the HUNTERSTOWN ROAD SUPERFUND SITE STRABAN TOWNSHIP, ADAMS COUNTY, PENNSYLVANIA I. INTRODUCTION Site Name: Site Location: Lead Agency: Support Agency: Hunterstown Road Superfund Site Straban Township, Adams County, Pennsylvania U.S. Environmental Protection Agency, Region III Pennsylvania Department of Environmental Protection Statement of Purpose The U.S. Environmental Protection Agency (EPA) is issuing this Explanation of Significant Differences (ESD) in accordance with Section 117(c) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended (CERCLA), 42 U.S.C. § 9617(c), and Section 300.435(c)(2)(i) of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 C.F.R. § 300.435(c)(2)(i). Section 117(c) of CERCLA and Section 300.435(c)(2)(i) of the NCP require the publication of an ESD when modifications to the selected remedy are necessary, and such modification's significantly change, but do not fundamentally alter, the remedy selected in a Record of Decision (ROD) with respect to scope, performance, or cost. EPA selected the remedy for the Hunterstown Road Superfund Site (the Site) in the following ROD and three ESDs: an August 2, 1993 ROD (1993 ROD), an August 25, 1998 ESD (1998 ESD), a March 22, 2001 ESD (2001 ESD) and an August 11, 2003 ESD (2003 ESD). The ROD and three ESDs collectively comprise the selected remedy for the Site (Selected Remedy). Significant changes need to be made to the Selected Remedy in order for the remedy to be protective of human health and the environment. This ESD (Fourth ESD) makes three modifications to the Selected Remedy in regards to institutional controls, groundwater performance standards, and a cumulative risk evaluation. Specifically, the institutional controls (ICs) for the groundwater component of the Selected Remedy do not fully encompass all areas where groundwater contamination is present or protect the entire groundwater extraction and treatment system. This Fourth ESD modifies the Selected Remedy by expanding the groundwater ICs to encompass the areal extent of groundwater contamination. This Fourth ESD also changes the groundwater performance standards from background levels to federal Maximum Contaminant Levels (MCLs), federal non-zero Maximum Contaminant Level Goals (MCLGs) or Pennsylvania Medium Specific Concentrations (MSCs). MCLs are the maximum permissible levels of a contaminant in public water supplies under the federal Safe Drinking
12
Embed
FOURTH EXPLANATION OF SIGNIFICANT DIFFERENCES (ESD)
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
ORIGINALSEMS DocID 2298711
FOURTH EXPLANATION OF SIGNIFICANT DIFFERENCES
for theHUNTERSTOWN ROAD SUPERFUND SITE
STRABAN TOWNSHIP, ADAMS COUNTY, PENNSYLVANIA
I. INTRODUCTION
Site Name:
Site Location:
Lead Agency:
Support Agency:
Hunterstown Road Superfund Site
Straban Township, Adams County, Pennsylvania
U.S. Environmental Protection Agency, Region III
Pennsylvania Department of Environmental Protection
Statement of Purpose
The U.S. Environmental Protection Agency (EPA) is issuing this Explanation of Significant
Differences (ESD) in accordance with Section 117(c) of the Comprehensive Environmental
Response, Compensation, and Liability Act, as amended (CERCLA), 42 U.S.C. § 9617(c), and
Section 300.435(c)(2)(i) of the National Oil and Hazardous Substances Pollution Contingency
Plan (NCP), 40 C.F.R. § 300.435(c)(2)(i). Section 117(c) of CERCLA and Section
300.435(c)(2)(i) of the NCP require the publication of an ESD when modifications to the
selected remedy are necessary, and such modification's significantly change, but do not
fundamentally alter, the remedy selected in a Record of Decision (ROD) with respect to scope,
performance, or cost.
EPA selected the remedy for the Hunterstown Road Superfund Site (the Site) in the following
ROD and three ESDs: an August 2, 1993 ROD (1993 ROD), an August 25, 1998 ESD (1998
ESD), a March 22, 2001 ESD (2001 ESD) and an August 11, 2003 ESD (2003 ESD). The ROD
and three ESDs collectively comprise the selected remedy for the Site (Selected Remedy).
Significant changes need to be made to the Selected Remedy in order for the remedy to be
protective of human health and the environment. This ESD (Fourth ESD) makes three
modifications to the Selected Remedy in regards to institutional controls, groundwater
performance standards, and a cumulative risk evaluation. Specifically, the institutional controls
(ICs) for the groundwater component of the Selected Remedy do not fully encompass all areas
where groundwater contamination is present or protect the entire groundwater extraction and
treatment system. This Fourth ESD modifies the Selected Remedy by expanding the
groundwater ICs to encompass the areal extent of groundwater contamination. This Fourth ESD
also changes the groundwater performance standards from background levels to federal
Maximum Contaminant Levels (MCLs), federal non-zero Maximum Contaminant Level Goals
(MCLGs) or Pennsylvania Medium Specific Concentrations (MSCs). MCLs are the maximum
permissible levels of a contaminant in public water supplies under the federal Safe Drinking
Water Act and codified at 40 C.F.R. Part 141. MCLGs are the levels of a contaminant in
drinking water below which there is no known or expected risk to health. MSCs are
Pennsylvania health standards for remediating contaminated sites. In addition to selecting new
groundwater performance standards for the Site, EPA is also requiring that a cumulative risk
evaluation be performed once MCLs, MCLGs and MSCs for the contaminants of concern (COC)
have been reached. Additionally, this Fourth ESD lists the COCs for the Site.
The information EPA has relied upon or considered to date in issuing this ESD has been added to
the Administrative Record for the Site in accordance with Section 300.825(a)(2) of the NCP.
The Administrative Record is available for public review at the locations listed below:
Adams County Public Library
140 Baltimore Street
Gettysburg, Pennsylvania 17325
(717)334-5716
U.S. Environmental Protection Agency, Region III
Administrative Record Reading Room
1650 Arch Street
Philadelphia, PA 19103-2029
(215) 814-3157Hours: Monday - Friday: 8:00 AM to 4:00 PM
Please call to schedule an appointment.
The Administrative Record is also available online at:
https://semspub.epa.gov/src/collection/Q3/AR108
H. SUMMARY OF SITE HISTORY. CONTAMINATION, AND SELECTED
REMEDY
A. Site History and Contamination
The Site is located on the east and west side of Hunterstown Road about 1.5 miles northeast of
downtown Gettysburg in Straban Township, Adams County, Pennsylvania (Figure 1). The
property owner, who operated a septic tank cleaning business, dumped waste at seven locations
on the property. The property is referred to as the Shealer property, which is comprised of two
parcels, one on each side of Hunterstown Road. The seven disposal areas are referred to as
Drum Burial Area 1, Drum Burial Area 2, North Cornfield Area, South Cornfield Area, Lagoon
Area, Stressed Vegetation Area and Borrow Area (Figure 1). The majority of the waste
consisted of paint sludge and various solvents. The disposal activities contaminated
groundwater, soil, surface water and sediment.
In 1983, the Pennsylvania Department of Environmental Resources, currently known as the
Pennsylvania Department of Environmental Protection (PADEP), initiated an investigation into
the dumping on the property as a result of a complaint from the Adams County Community
Environmental Control Office. In 1984, EPA issued an administrative order to conduct a
2
removal action, requiring the Westinghouse Electric Corporation, one of the Potentially
Responsible Parties (PRPs) that had generated waste found at the Site, to provide potable water
to affected residents and remove all sludges and liquid materials from the Lagoon Area. The Site
was added to the National Priorities List in June 1986. Westinghouse Electric Corporation
conducted the removal of a large number of buried drums from December 1988 through May
1989.
In December 1988, the remedial investigation and feasibility study (RI/FS) was initiated. Based
on the Rl, the most significant surface soil contaminants included antimony, barium, copper,
chromium, lead, mercury, vinyl chloride and 1,1-dichloroethene (1,1-DCE). The most
significant contaminants in groundwater were volatile organic compounds (VOCs), including
trichloroethene, 1,1,1-trichloroethane, vinyl chloride, 1,1-DCE, 1,1-dichloroethane and 1,2-
dichloroethane. There are two distinct groundwater plumes (Figure 2). One of the groundwater
plumes originated from Drum Burial Area 1 and is located to the west of Hunterstown Road.
The other groundwater plume, located east of Hunterstown Road, originated from all the other
disposal areas on the Shealer property.
B. Selected Remedy
EPA issued the 1993 ROD selecting a remedy for the Site. The remedy for the Site was
modified by the 1998 ESD, 2001 ESD, and 2003 ESD. Although Remedial Action Objectives
were not specifically identified, the ROD states that the implementation of this remedy would
effectively eliminate the potential risk to human health which may result from exposure to
contaminated groundwater, soils and sediments from the Site.
The Selected Remedy consists of the following components:
Table 1 — Groundwater Performance Standards for Site-related Contaminants of Concern
(COC)
COC MCL/Non-Zero MCLG MSC
1,1,1 -Trichloroethane
1,1,2-Trichloroethane
200 (ig/L3 gg/L
1,1-Dichloroethane 31 gg/L
1-Dichloroethene 7 gg/L
1,4-Dioxane 6.4 gg/L
cis-1,2-Dichloroethene 70 gg/L
Trichloroethene 5 gg/LVinyl Chloride 2 gg/L
Legend:pg/L - micrograms per liter COC - Contaminant of Concern MCL - Maximum Contaminant Level MCLG - Maximum Contaminant Level Goal MSC - Medium Specific Concentration 1 — Non-zero MCLG
Applicable or Relevant and Appropriate Requirements for Groundwater Performance Standards
1. MCLsand MCLGs - 40 C.F.R. Part 1412. MSCs - 25 Pa Code Section 250 Appendix A