PB99-963103
EPA541-R99-003
1999
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Chem-Solv Inc. Site
Cheswold, DE
6/18/1999
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EXPLANATION OF SIGNIFICANT DIFFERENCES
CHEM-SOLV, INC. SUPERFUND SITE
I. INTRODUCTION
Site Name: Chem-Solv, Inc. Superfund Site
Site Location: Cheswold, Kent County, Delaware
Lead Agency: U.S. Environmental Protection Agency Region III
("EPA" or "the Agency")
Support Agency: Delaware Department of Natural Resources and Environmental Control
("DNREC" or "the State")
Statement of Purpose
A Record of Decision ("ROD") for the Chem-Solv, Inc. Superfund Site ("Site") was
signed on March 29,1992. This Explanation of Significant Differences ("ESD") is being issued
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), which require EPA to publish an explanation of
significant differences when a remedial action is taken that differs significantly from, but does
not fundamentally alter, the remedy selected in the ROD with respect to scope, performance, or
cost. This ESD will become a part of the Administrative Record file for the Site.
II. SUMMARY OF THE SITE HISTORY, SITE CONDITIONS, AND SELECTED
REMEDY
The Site is a former solvent recovery facility which is no longer in operation. An
explosion and fire at the Chem-Solv, Inc. facility in 1984 resulted in a solvent spill and
subsequent ground water contamination. The ROD for the Site requires remediation of ground
water contaminated with volatile organic compounds ("VOCs") and manganese and addresses
drinking water sources potentially affected by the contamination.
The major components of the selected remedy as outlined in the ROD are:
• Collection of contaminated ground water using recovery wells until cleanup levels are
achieved;
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• Discharge of extracted ground water to the local Publicly Owned Treatment Works
("POTW") via the Kent County sewer system or. if an agreement with the POTW cannot
be reached, a contingency for onsite treatment of extracted ground water and discharge to
local surface water;
• Continued ground water monitoring at domestic, recovery, and monitoring wells until
cleanup levels are achieved;
• Provision of an alternate water supply to residences should their drinking water wells
become contaminated before the remedial action is completed;
• Establishment and enforcement of a State Ground Water Management Zone ("GWMZ")
to prevent the installation of drinking water wells in the contaminated portion of the
Columbia aquifer until cleanup levels are achieved;
• Placement of a notice of the GWMZ in the property records of all properties located
within the GWMZ until cleanup levels are achieved; and
• Removal of existing recovery wells onsite.
III. DESCRIPTION OF SIGNIFICANT DIFFERENCE
The ROD for the Site requires the State to institute a GWMZ throughout which the
installation of drinking water supply wells will not be permitted in the unconfmed Columbia
aquifer until EPA determines that the ground water cleanup levels have been achieved. The ROD
further requires the placement of a notice in the property records of each property located within
the GWMZ in order to notify present and potential future property owners that the property is
located within the GWMZ.
Such notices are no longer necessary to alert prospective purchasers of property within
the GWMZ that the property is located in the GWMZ and to the potential for contamination of
the property drinking water supply well. With one exception, all drinking water wells completed
in the contaminated Columbia aquifer and remaining in the GWMZ were replaced, from 1996 to
1998, with water supply wells in a deeper confined aquifer which has not been affected by the
Site contamination. A shallow drinking water well still supplies residents of the former Chem-
Solv, Inc. property, which is located within the GWMZ. However, a copy of the Administrative
Order, Docket No. 111-93-11 -DC, for Remedial Design and Remedial Action ("Order") at the
Chem-Solv, Inc. Site, including the ROD, has been submitted to the Recorder of Deeds for Kent
County, Delaware, for recording in order to bring conditions at the Site to the attention of any
person examining the title to the property where the former Chem-Solv, Inc. facility was located.
Furthermore, EPA has two concerns regarding the implementation of property notices. It
is often impracticable to record notices in property records since, in almost all cases, such notices
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must be signed by the property owner. In addition, such notices would remain permanently in
issledTd^iTe?' P°tentiaIIy Stigmati2ing ** Pr°perty' even if a ^bsequ^nScTwere
Finally, EPA has determined that the State's implementation of the GWMZ and the
provision of alternate water supplies by the parties implementing the ROD under the Order are
sufficient to protect human health while progress is being made toward the attainment of gro^d
water cleanup levels. Therefore, the modified remedy which will be unptaeni^K
w thfn ^r™Vr!rre ^ PlaC6ment °f a n°tiCe in ^ Pr0perty records of Properties located
within the GWMZ that such property is located within the GWMZ.
IV. AFFIRMATION OF THE STATUTORY DETERMINATIONS
Considering developments at the Site and the change that has been made to the selected
remedy under this ESD, EPA and DNREC believe that the remedy remains protective of human
health and the environment, complies with federal and State requirements that are applicable or
relevant and appropriate to this remedial action, and is cost-effective. In addition, the revised
remedy uses permanent solutions and alternative treatment (or resource recovery) technologies to
the maximum extent practicable for this Site.
V. PUBLIC PARTICIPATION
This ESD will become a part of the Adminstrative Record file for the Site. The
Administrative Record file is available for review at the following locations:
U.S. EPA, Region III, Docket Room
1650 Arch Street
Philadelphia, PA 19103-2029
(215)814-3157
Mon. - Fri. 9:00 a.m. - 4:30 p.m.
State of Delaware
DNREC/DAWM
391 Lukens Drive
New Castle, DE 19720
(302) 395-2600
Mon. - Fri. 8:00 a.m. - 4:30 p.m.
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William C. Jason Library
Delaware State'College
1200 North Dupont Highway
Dover, DE 19901
(302)739-3571
Mon. - Thur. 8:00 a.m. - 11:00 p.m.
Fri. 8:00 a.m. - 5:00 p.m.
Sat. 9:00 a.m. - 5:00 p.m.
Sun. 2:00 p.m.- 10:00 p.m.
Questions or comments on EPA's actions can be directed to:
Debra Rossi (3HS23)
Remedial Project Manager
U.S. EPA, Region III
1650 Arch Street
Philadelphi, PA 19103-2029
(215)814-3228
Pursuant to Section 117(c) of CERCLA, 42 U.S.C. § 9617(c), and Section
300.435(c)(2)(i)(B) of the NCP, 40 C.F.R. § 300.43 5(c)(2)(i)(B), a notice summarizing this ESD
and informing the public of its availability is being published in the Delaware State News.
VI. SUPPORT AGENCY REVIEW
The State of Delaware has concurred with this ESD.
Date Abraham Ferdas
Director, Hazardous Site Cleanup Division
U.S. Environmental Protection Agency
Region III
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