PB97-963110
EPA/541/R-97/016
November 1997
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Industrial Lane,
Williams Township, PA
12/5/1996
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EXPLANATION OF SIGNIFICANT DIFFERENCES
INDUSTRIAL LANE SUPERFDND SITE
I. INTRODUCTION
Site Name: Industrial Lane Superfund Site
Site Location: Williams Township, Northampton County,
Pennsylvania
Lead Agency: U.S. Environmental Protection Agency, Region III
("EPA")
Support Agency: Pennsylvania Department of Environmental
Protection ("PADEP") (formerly the
Pennsylvania Department of Environmental
Resources)
Statement of Purpose
EPA issued a Record of Decision ("ROD") for operable unit 2
("OU2") of the Industrial Lane Superfund Site ("Site") on March
29, 1991. This Explanation of Significant Differences ("BSD") is
issued in accordance with Section 117(c) of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980,
as amended ("CERCLA"), 42 U.S.C. § 9617(0), and Section 300.435
(c)(2)(i) of the National Oil and Hazardous Substance Pollution
Contingency Plan ("NCP"), 40 C.F.R. § 300.435(c)(2)(i). EPA is
required to publish an explanation of significant differences if
the remedial action taken at a site differs significantly from
the remedy selected in a Record of Decision, and such differences
significantly change, but do not fundamentally alter, the remedy
selected in the Record of Decision with respect to scope,
performance, or cost. This BSD has been prepared to provide the
public with an explanation of the nature of the changes made to
the selected remedy for the cleanup of contaminated ground water
identified in the ROD for OU2, to summarize the information that
led to the making of the changes, and to demonstrate that the
revised remedy complies with the statutory requirements of
Section 121 of CERCLA, 42 U.S.C. § 9621. The remedy changes do
not fundamentally alter the remedy or performance of the remedy,
and therefore a ROD amendment is not required. This BSD is
incorporated into the Administrative Record file for the Site.
The location of the Administrative Record file is set forth in
Section VI of this BSD.
II. SUMMARY OF THE SITE HISTORY, CONTAMINATION PROBLEMS, AND
SELECTED REMEDY
The Site is located in Williams Township, Northampton
County, Pennsylvania, approximately 1 mile southwest of the
center-of south Easton (Attachment 1). Although the Site is
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listed as Industrial Lane on the National Priorities List
("NPL"), it is located on Industrial Drive. The Site, which
encompasses approximately 30 acres, borders on the city limits of
Easton, and is located approximately 15 miles east of Allentown.
The Lehigh River and Lehigh Canal are located to the northwest of
the Site. The communities of Glendon Borough and Lucy's Crossing
are located west and southwest of the Site, respectively. Morgan
Hill is situated to the east and south of the Site. The area
population has been estimated at approximately 550 persons.
The Site includes the inactive portion of a sanitary
landfill called the Chrin Brothers Landfill. The Chrin Brothers
Landfill began operating in 1961 and gradually expanded. In
1975, the Pennsylvania Department of Environmental Resources
("PADER") issued a permit for the landfill as a natural
renovation sanitary landfill that was approved to receive
municipal solid waste. No liner was required, and industrial
wastes were not to be accepted without prior PADER approval. By
1980, the landfill had expanded to 30 acres. Disposal of wastes
in this unlined area ceased in 1986. PADER issued a permit in
1986 for a 10-acre expansion of the Chrin Brothers Landfill. The
expansion area has been developed east of the unlined landfill
and includes a liner and leachate collection system. This
operating, lined landfill continues to accept wastes for
disposal, and the Chrin Brothers Landfill has received approval
to further expand the lined landfill area.
EPA proposed the Site (the inactive, unlined portion of the
landfill and the adjacent areas under which contaminated ground
water has migrated) for the NPL in 1983 after contamination was
found in local wells. The Site was placed on the NPL in 1984. A
Remedial Investigation/Feasibility Study ("RI/FS") was completed
in 1986 pursuant to Section 104 of CERCLA, 42 U.S.C. § 9604. The
RI/FS revealed that there is a plume of ground water
contamination beneath the Site consisting primarily of volatile
organic compounds. On September 29, 1986, EPA issued a ROD for
operable unit 1 ("OU1") at the Site, which addressed the threat
to human health in the area from drinking contaminated ground
water. The remedy under the ROD for OU1 consisted of connecting
numerous private well users in Lucy's Crossing and Glendon
Borough to existing water mains belonging to the Easton City
Suburban Water Authority. This remedial action was completed by
EPA in 1988.
On March 29, 1991, EPA issued the ROD for OU2, which
addressed contaminated ground water at the Site. The selected
remedy set forth in the ROD for OU2 included the following
components:
1. Closure of the inactive, unlined portion of the
landfill;
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2. Ground water extraction and treatment, and discharge of
treated ground water to the Lehigh River; and
3. Long-term monitoring of the landfill closure and the
ground water extraction and treatment system.
III. DESCRIPTION OP SIGNIFICANT DIFFERENCES AND THE BASIS FOR
THOSE DIFFERENCES
EPA has determined that certain changes in the remedy set
forth in the ROD for OU2 are warranted. These changes are
significant changes as defined in Section 300.435(c)(2)(i) of the
NCP, 40 C.F.R. § 300.435(c)(2)(i); therefore, preparation of this
BSD is required. A ROD Amendment is not required because the
changes do not fundamentally alter the selected remedy.
A. Description of the Changes
1. Cap
The ROD for OU2 specified that the inactive, unlined portion
of the landfill should be closed according to the closure
requirements of Chapters 271 and 273 of the Pennsylvania
Municipal Waste Management Regulations (25 PA. Code Chapters 271
and 273). Section 273.234 of the regulations requires an
impermeable cap of clay or synthetic membrane over the entire
surface of any applicable landfill closed after April 9, 1988.
In the ROD for OU2, this requirement was applied to the unlined
portion of the landfill at the Site. This was based on the
intention of the landfill owner at that time to operate the
unlined portion of the landfill for a short period of time after
the ROD for OU2 was issued. However, subsequent to the issuance
of the ROD for OU2, the owner decided not to add additional
wastes to the unlined portion of the landfill. Since that
portion of the landfill had been shut down before the April 9,
1988 applicability date for. the new landfill closure regulations
set forth in Section 273.234, the closing of the unlined portion
of the landfill was subject to the abatement regulations set
forth in Section 273.287 of the Pennsylvania Municipal Waste
Management Regulations (25 PA. Code § 273.287), applicable to
landfills closed prior to April 9, 1988, rather than the closure
regulations set forth in Section 273.234. The cap that was
constructed over the inactive, unlined portion of the landfill,
consisting of a synthetic membrane cap over the top of the
landfill and a soil cap over the sides of the landfill, meets the
landfill abatement regulations set forth in Section 273.287. In
a letter dated November 15, 1995, the landfill owner requested
that EPA revise the ROD for OU2 to require that the landfill cap
meet the abatement regulations rather than the closure
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regulations. In a letter dated January 25, 1996, from James E.
Kunkle of PADEP, to Gregory Ham of EPA, PADEP concurred with the
proposed revision.
2. Ground Water Treatment Standards
The selected remedy set forth in the ROD for OU2 includes a
ground water extraction and treatment system to address the
contamination that is migrating from the unlined portion of the
landfill. The extraction and treatment system was intended to
collect the contaminated ground water, treat it to standards
specified in Table 12 of the ROD for OU2, and discharge the
treated water to the Lehigh River. The ground water treatment
standards set forth in Table 12 were based on the Pennsylvania
requirement that contaminated ground water be cleaned up to
background levels, i.e.. those levels of each contaminant that
would be found in the area in the absence of a source of
contamination (the Site). For most of the contaminants, the
level specified was the minimum detection limit. This
requirement resulted in cleanup standards that were more
stringent than those that would have been required under federal
standards in the absence of this Pennsylvania applicable or
relevant and appropriate requirement ("ARAR").
Subsequent to the issuance of the ROD for OU2, the
Pennsylvania General Assembly enacted the Pennsylvania Land
Recycling and Environmental Remediation Standards Act, No. 1955-
2, 35 P.S. §§ 6026.101 ej£ sgfl. ("Act 2"), which became effective
on July 18, 1995. Act 2 allows several alternatives for setting
cleanup standards for contaminated ground water. One
alternative is to use human health based standards, rather than
background levels. In the November 15, 1995 letter to EPA, the
owner of the landfill requested that EPA revise the cleanup
standards in the ROD for OU2 to reflect standards that would be
allowed under Pennsylvania's Act 2. In the letter dated January
25, 1996, from James E. Kunkle of PADEP, to Gregory Ham of EPA,
PADEP concurred with this change proposed in the November 15,
1995 letter from the landfill owner. In addition, PADEP asserted
in the January 25, 1996 letter that Act 2 is an applicable state
ARAR for the ground water remedial action and should be
recognized by EPA in the ROD modification document.
Pursuant to Section 300.430 (f) (1) (ii) (B) (1) and (2) of the
NCP, 40 C.F.R. § 300.430(f) (1) (ii) (B) (1) and (2), EPA is not
required to revise ARARs after issuance of a Record of Decision
unless (1) such revision is necessary to ensure that the remedy
is protective of human health and the environment, or (2) a new
component is added to a remedy after issuance of a Record of
Decision and such new component must attain requirements that are
identified as ARARs at the time an amendment to the Record of
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Decision or an explanation of significant differences describing
the component is issued. Neither situation applies with respect
to the Site. Nonetheless, under appropriate circumstances, EPA
can remove a State requirement that had been asserted as an ARAR
at the time a Record of Decision was issued but which has
subsequently been repealed or modified.
Pennsylvania's Act 2, which became effective on July 18,
1995, modified the Pennsylvania absolute requirement (set forth
in 25 PA. Code §§ 264.90 - 264.100, specifically in 25 PA. Code
§§ 264.97 (i) and (j) and § 264.100(a) (9)), that ground water
contaminated with hazardous substances must be cleaned up to the
background levels described in that requirement. See Section
908(b) of Act 2. Although PADEP has identified Act 2 as an ARAR
for this remedy, EPA has determined that Act 2 does not, on the
facts and circumstances of this remedy, impose any requirements
more stringent than the federal standards. As a result, the
ground water cleanup standards for the Site will be the Federal
Maximum Contaminant Levels ("MCLs") set forth in 40 C.F.R.
§ 141.61 or non-zero Maximum Contaminant Level Goals ("MCLGs")
set forth in 40 C.F.R. § 141.50, whichever are more stringent,
pursuant to the Safe Drinking Water Act, 42 U.S.C. §§ 300f et.
seq., which would have been relevant and appropriate requirements
at the time the ROD for OU2 was issued in the absence of the
Pennsylvania requirement of cleanup to background levels. For
1,1-dichloroethane, there is no MCL or non-zero MCLG. PADEP
proposed the use of a cleanup standard that has been developed by
the Commonwealth of Pennsylvania for use under its' Act 2
program. This standard was developed using standard EPA risk
assessment guidance. After evaluating this proposed standard,
EPA believes that it is appropriate as a "to be considered"
(TBC), and would be protective of human health and the
environment. TBCs can be guidance or policy documents developed
by a state that are not in themselves ARARs, but that are used to
implement regulations. These can be used as appropriate to
ensure protectiveness of a remedy. EPA believes that this is
appropriate as a TBC, and therefore is using this cleanup
standard for this compound.
Attachment 2 to this ESD lists the original cleanup
standards specified in Table 12 of the ROD for OU2, along with
the revised cleanup standards that are being approved in this
ESD.
3. Discharge of Treated Ground Water
As noted above, the ROD for OU2 called for discharge of the
treated ground water to the Lehigh River. In the November 15,
1995 letter to EPA, the landfill owner requested that EPA revise
the ROD for OU2 to allow discharge of the treated ground water to
other locations, provided that they are approved by PADEP and
that the owner obtains a valid discharge permit from PADEP under
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the National Pollution Discharge Elimination System ("NPDES")
program. In the letter dated January 25, 1996, from James E.
Kunkle of PADEP, to Gregory Ham of EPA, PADEP concurred with this
proposed revision.
B. Rationale for the Change
EPA has determined that the changes to the ROD for OU2
described above are needed, and that implementation of the
revised remedy will be protective of human health and the
environment based on the information and facts described below:
1. Performance
The change in the cap design should have a minimal impact on
the overall performance of the cap. The top area of the landfill
has a multi-layer cap with a synthetic membrane preventing
infiltration of precipitation. The sides of the landfill have a
vegetated soil cap. The performance of this cap will be
monitored, and if it is not successful in maintaining the
integrity of the waste material and minimizing infiltration of
precipitation into the wastes, PADEP and/or EPA may require the
installation of a full cap. Since the change in the cap provides
for a cap that is protective of human health and the environment
and meets the requirements for a landfill that closed prior to
April 9, 1988, EPA has determined that this is an appropriate
method for closing the inactive portion of the landfill.
With respect to the ground water cleanup standards, the
extraction system is designed to capture contamination migrating
from the landfill. No changes are being made to the design of
the extraction system as a result of this BSD (although the
approved design of the extraction system does differ from the
conceptual plan that was presented in the ROD for OU2). The
cleanup standards set forth in Table 12 of the ROD for OU2 were
based on the instrument detection limit for each contaminant,
which is the theoretical lowest amount of a contaminant that can
be detected in an aqueous sample. Some of these limits are below
the practical quantitation limits, which are the lowest levels
that can be detected by laboratory equipment on a normal day-to-
day basis, so some of these standards were not achievable. In
addition, Pennsylvania's Act 2 modified the absolute requirement
that ground water in Pennsylvania be cleaned up to background
levels as required by 25 PA. Code §§ 264.90 - 264.100,
specifically in 25 PA. Code § 264.97(i) and (j) and §§
264.100(a)(9).
The description of the selected remedy in Section IX of the
ROD for OU2, at page 41, states that "...the aquifer would be
remediated until the contaminant levels reach MCLs, non-zero
MCLGs, or background [i.e.. as specified by 25 PA. Code §§ 264.90
- 264.100, specifically in 25 PA. Code §§ 264.97 (i) and (j) and
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264.100(a)(9)], whichever are lower." Thus, MCLs or non-zero
MCLGs would be the ARAR in instances where the former background
level was not. Where no MCL or MCLG exists, a site specific risk
based number must be calculated. Although PADEP has identified
Act 2 as an ARAR for this remedy, EPA has determined that Act 2
does not, on the facts and circumstances of this remedy, impose
any requirements more stringent than the federal standard.
Accordingly, with the approval of PADEP, EPA is using MCLs or
non-zero MCLGs, whichever are more stringent, as the ground water
cleanup standards at the Site, instead of the previous
background standards. The MCLs and non-zero MCLGs are protective
and do not change the selected remedy. For one compound (1,1-
dichloroethane) there is no MCL or non-zero MCLG. For that
compound, the cleanup standard will be the concentration
developed by PADEP for that compound under its' Act 2 program.
This standard is a "to be considered" and not an ARAR, but is
protective of human health and the environment and is consistent
with the National Contingency Plan.
The final change being made to the selected remedy is to
allow discharge of the treated ground water at any location that
is approved by PADEP under the NPDES program. The ROD called for
discharge of the treated water to the Lehigh River; however,
there may be other suitable discharge points closer to the Site
that would not require as extensive a discharge line. As long as
these alternate locations are approved and meet the applicable
discharge criteria under the NPDES permit, there is no reason to
require discharge of the treated ground water directly to the
Lehigh River.
2. Timing
The timing for the construction of the remedy will not
change significantly due to these revisions. The time required
to treat the ground water may be reduced slightly due to the
change in the cleanup standards, but is still estimated to be
approximately thirty years. This change is not expected to be
significant, and the revised cleanup standards are still
protective of human health. The cap has already been constructed
in accordance with the revised requirements discussed above.
Therefore, the cap remedy is currently in compliance with these
revised requirements. The piping for discharge of the treated
ground water has not yet been constructed. By allowing the
landfill owner to select any approved location for the discharge,
the most efficient location can be chosen, minimizing the time
necessary for construction and making the construction cost-
effective.
3. Costs
The costs for the remedy will not change significantly due
to the changes set forth in this BSD. Some savings will be
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realized due to the change in the location of the discharge, the
change in the cap design, and the slight shortening of the period
of treatment of the ground water.
IV. SUPPORT AGENCY COMMENTS
EPA notified the PADEP of the changes proposed in this ESD
in accordance with 40 C.F.R. § 300.435(c) (2). By letter dated
December 4, 1996, from William F. McDonell, PADEP Regional
Director, to Mr. W. Michael McCabe, EPA Regional Administrator,
PADEP informed EPA that it concurs with this ESD. A copy of this
letter has been placed in the Administrative Record file.
V. AFFIRMATION OF THE STATUTORY DETERMINATIONS
EPA has determined that the revised remedy complies with the
statutory requirements of Section 121 of• CERCLA, 42 U.S.C.
§ 9621. Considering the new information that has been developed
and the changes that have been made to the selected remedy, EPA
believes 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 in accordance with Section 121(d) of CERCLA, 42 U.S.C.
§ 9621(d), and is cost-effective. In addition, the revised
remedy utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable for this Site.
VI. PUBLIC PARTICIPATION
The ESD and the information upon which it is based have been
included in the Administrative Record file and the information
repository for the Site. The Administrative Record file is
available for public review at the locations listed below:
U.S. EPA, Region III
841 Chestnut Building
Philadelphia, PA . 19107
Hours: Mon. - Fri., 9:00 a.m. - 4:00 p.m.
Mary Meuser Library
1803 Northampton Street
Easton, PA 18042
610-258-3040'
Hours: Mon. - Fri., 10:00 a.m. - 8:30 p.m.
Sat., 10:00 a.m. - 1:00 p.m.
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Questions concerning EPA's action and requests to review the
Administrative Record should be directed to:
Gregory Ham
Remedial Project Manager
U.S. EPA - Region III
841 Chestnut Building
Philadelphia, PA 19107
(215) 566-3194
[3HW2D
Date
Theffnas C. Volt
Hazardous Wast
__ rector
agement Division
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GROUND WATER CLEANUP STANDARDS
INDUSTRIAL LANE SUPERFUND SITE
(aka Chrin Landfill)
Contaminant
Vinyl Chloride
Methylene Chloride
1,1 - Dichloroethane
trans - 1,2 - Dichloroethene
cis - 1,2 - Dichloroethene
Chloroform
1,2 - Dichloroethane
1,1,1- Trichloroethane
Carbon Tetrachloride
1,2 - Dichloropropane
Benzene
Tetrachloroethene
1,4 - Dichlorobenzene
Chlorobenzene
1,1 - Dichloroethene
Trichloroethene
Original Cleanup
Level
(ROD)
0.18
0.25
0.07
0.1
0.12
0.05
0.03
0.03
0.12
0.04
0.2
0.03
0.3
0.2
0.13
0.03
Revised Cleanup
Level (ESD)
2
5
27
100
70
100
5
200
5
5
5
5
75
100
7
5
All units in parts per billion.
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