PB98-963115
EPA 541-R98-049
October 1998
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
CryoChem, Inc.
OU 3 (Contamination Soil)
Worman, PA
9/22/1998
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EXPLANATION OF SIGNIFICANT DIFFERENCES
CRVOCHEM SUPERFUND SITE
OPERABLE UNIT 3 (CONTAMINATED SOIL)
EARL TOWNSHIP, PENNSYLVANIA
I. Introduction
This Explanation of Significant Differences (ESD) has been prepared by the U.S.
Environmental Protection Agency Region III (EPA), to address contaminated soil at the
CryoChem Superfund Site (the Site), located in the Earl Township, approximately 3 miles west
of Boyertown, Pennsylvania. The ESD documents changes to the CryoChem Superfund Site
Record of Decision (ROD) for the contaminated soil Operable Unit 3 (OU3), which was signed
on September 30,1991. The ESD is issued in accordance with Section 117(c) of the
Comprehensive Environmental Response, Compensation and Liability Act, as amended
(CERCLA), commonly known as Superfund, 42 U.S.C. § 9617(c), and 40 C.F.R.
§ 300.435(c)(2)(I).
EPA is issuing this ESD to document a change in the selected remedial action for OU3,
from the utilization of soil vapor extraction to remove the contamination from the soil, to no
further action. This action is protective of human health and the environment, and complies with
Federal and State applicable or relevant and appropriate requirements for this action.
OU1, which addresses drinking water (see discussion below) and OU2, which addresses
groundwater contamination (see discussion below), combine to address fully the threats posed by
the conditions at the Site. The ESD selects a remedial action for OU3, which was originally
described as Alternative 1 of the ROD for OU3. EPA's proposal is based upon the following
circumstances:
On September 30, 1991, EPA issued the ROD for OU3. The selected remedial action
included, as a major component, the "utilization of soil vapor extraction to remove the
contamination from the soil."
• During the Remedial Investigation (RI), elevated levels of hazardous substances were
detected in surficial soils behind the fabrication building, indicating that solvent had been
disposed of there, and that it may have contributed to the groundwater contamination
found on- and off-site. The contaminated soil continued to contribute to the threat posed
by the Site as hazardous substances leached from the soil into the groundwater and
migrated into surface water via overland flow.
• EPA's subsequent investigations, completed in 1992,1995, and 1996, revealed that
significant changes have occurred since the RI was completed and the OU3 ROD was
finalized. This document summarizes the rationale for selecting the original remedial
alternative in the OU3 ROD, provides the results of the recent investigations, presents
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conclusions regarding the anticipated f;fficacy of the selected remedy, and the selection oL
no funher action as the remedial action for OU3.
EPA is the lead agency for Site activities and the Pennsylvania Department of
Environmental Protection (PADEP) is the support agency for the Site. PADEP was provided
with a copy of the technical report summarizing the investigations and the proposed ESD.
PADEP had no comments on the technical report, as noted in a letter dated April 4, 1997, and
concurred with the ESD, as noted in a letter August 31,1998..
This document presents a summary of the changes to the remedy selection in the ROD for
OU3, and a synopsis of information regarding the Site. The ESD will become part of the
Administrative Record file pursuant to 40 C.F.R. § 300.825(a)(2), whJch includes the complete
documentation relating to the CryoChem Site. A copy of the Administrative Record file is
located at:
U.S. Environmental Protection Agency
1650 Arch Street
Philadelphia, PA 19103
Hours: Monday-Friday 9:00-4:00
215-566-3157
and
Earl Township Supervisors Building
RD#3,Box571
Boyertown,PA 19512
II. Summary of Site History. Contamination Problems^ and Selected Remedy
The CryoChem Superfund Site is located along Route 562 in Earl Township, Berks
County, Pennsylvania and is approximately 3 miles west of Boyertown in Earl Township (Figure
1). CryoChem, Inc. has been manufacturing metal products at the Site since 1962. CryoChem's
metal fabrication process previously included the use of a chemical solvent (containing at least
93.5% 1,1,1 trichioroethane) to clean dye used to check for faulty welds. The solvent was spilled
into shop drains and discarded at the rear of the fabrication building resulting in contamination to
a limited area of soil behind the fabrication building, and subsequently to the local ground water
system.
The Site is approximately nineteen acres in size, with CryoChem's manufacturing plant
and office buildings located on the southern four acres. Groundwater under the Site flows from
northwest to southeast and is controlled primarily by fractures in the bedrock.
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Environmental samples collected between 1981 and 1987 by PADEP, EPA, and other
parties, documented contamination of soil, ground water, and surface water near the Site and
several residential wells downgradient to the Site. Specifically, 1,1,1-trichJoroethane (TCA),
1,1-dichloroethane (DCA), tetrachJoroethene (PCE), trichloroethene (TCE) and 1,1-
dichloroethene (DCE) were detected in on-site soils and ground water wells.
On October 4,1989, EPA included the CryoChem Site on the National Priorities List (54
FR 41015). CryoChem, Inc. and several other potentially responsible parties (PRPs) conducted a
Remedial Investigation/ Feasibility Study at the Site under the supervision of EPA pursuant to an
Administrative Order by Consent siped by the PRPs and EPA in 1988. A Remedial
Investigation/ Feasibility Study was completed by the JACA Corporation in June 1990 on behalf
of the PRPs, consisting of investigations and studies to characterize the type and extent of
contamination related to the Site to develop alternatives to address the contamination problems.
A Focused Feasibility Study, which specifically addressed remedial alternatives for the soil, was
completed in May 1991 by the PRC Corporation, on behalf of EPA.
The major findings of the Remedial Investigation include:
• a plume of ground water extending from the Site to several springs located nearly 2500
feet southeast of the Site is contaminated by TCA, DCA, PCE, TCE, and DCE. Nearby
residential wells and an on-site production well are affected.
• a small area of shallow soil (approximately 70 yd3) in a confined area approximately 25
by 50 feet along the north wall of the fabrication building (near the containment pad
storing CryoChem Inc.'s fuel oil tank) contains TCA, TCE, PCE, DCA, ethylbenzene and
xylene.
On September 29,1989, EPA issued the ROD for OU1. The major components of this
ROD, which addressed drinking water at and near the Site, included:
1. Continued operation and maintenance, until a permanent clean water supply is
developed, of dual activated-carbon units installed at 20 homes affected by the
Site.
2. Installation, operation, and maintenance, until a permanent clean water supply is
developed, of dual activated-carbon units at homes affected by contamination
from the Site that are not currently equipped with carbon units.
3. Installation, operation, and maintenance of dual activated carbon units at
residential wells which become affected by contamination from the Site.
4. Development, construction, and operation of a new clean water supply well and
distribution system to provide clean water to affected and potentially affected
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homes and businesses. The new water supply would include an air stripper or
carbon adsorption unit(s) to treat the water if necessary.
EPA issued an ESD for OU1 on September 22, 1994, to change the selected remedial
action, from the development and construction of an alternate water supply, to the continued use
of carbon treatment units. EPA has continued to install, operate, and maintain dual activated
carbon units as necessary.
On September 28,1990, EPA issued a ROD for OU2. The major components of this
ROD, which addressed the ground water contamination at and near the Site, included:
1. Completion of a ground water remedial design study to determine the most
efficient design for a ground water treatment system.
2. Installation, operation, and maintenance of ground water extraction wells to
remove contaminated ground water from beneath the Site and to prevent
contaminants from migrating to currently unaffected areas.
3. Installation, operation, and maintenance of air stripping towers to treat ground
water to applicable levels.
4. Construction, operation, and maintenance of a pipeline from the air stripping
towers to surface water near the Site to discharge treated ground water.
5. Periodic ground water monitoring to ensure that the remedy is effective.
EPA completed construction of the ground water treatment system on May 23, 1998.
EPA anticipates that this system will remain operational for several years.
On September 30,1991, EPA issued a ROD for OU3. The major components of this
ROD, which addressed the soil contamination at the Site, included:
1. Sampling the contaminated area (and sampling two other areas) to better define
the extent of the contamination.
2. Utilization of soil vapor extraction to remove the contamination from the soil.
3. Confirmation sampling.
HI. Description of Significant Differences and the Basis for those Differences
EPA is issuing this ESD to change the selected remedial action for OU3 from the
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utilization of soil vapor extraction to remove the contamination from the soil to no further action.
The newly selected remedial action for OU3, as originally described as Alternative 1 of the ROD
for OU3, is protective of human health and the environment, and complies with Federal and State
applicable or relevant and appropriate requirements to this action.
The remedial alternatives for OU3 were developed to meet the remedial objectives of the
Site. These objectives were to protect public health, welfare, and environment, prevent further
migration of contaminants from the soil to the groundwater, and to prevent soil-contaminant
migration into unaffected areas. Since the contaminated soils found behind the fabrication
building were considered a potential source area, this area was targeted as the focus of OU3.
EPA evaluated five potentially applicable remedial technologies, management or process
options, and the requirement set forth in the NCP, 40 C.F.R. 300.430 (e)(6) to evaluate a No-
Action Alternative. EPA selected sampling of the contaminated soils, implementation of a soil
vapor extraction (SVE) procedure (i.e., in-situ or ex-situ), and subsequent confirmatory sampling
of the treated area. The Record of Decision specified that soil remediation would be considered
complete when the concentration of each contaminant identified for removal decreased to less
than 2 parts per million (ppm).
Post -ROD OU3 Investigations
Soil Sampling
In support of the pre-remedial design sampling requirement, EPA conducted two rounds
of soil sampling in the OU3 target area in 1992 and 1995. The sampling locations were selected
to be near the locations sampled during the RJ. These locations, which were originally selected
to coincide with solvent disposal areas, are shown on Figure 2. Table 1 provides a summary of
the analytical results from the 1992 and 1995 sampling rounds, and the historic analytical data
from the RI sampling in 1989. The results from the 1992 and 1995 sampling events indicate
significant reductions in contaminant concentrations since the 1989 event, and each of the
contaminants identified for removal were below the remediation goal of 2 ppm. These
reductions could be attributed to a combination of vertical migration into the groundwater,
overland transport into surface water bodies, and the natural breakdown of the contaminants into
non-hazardous substances.
Soil Gas Study
Based upon a clear indication of contaminant level reductions in the SVE target area over
the 6-year soil sampling period, a passive soil-gas study was performed in May 1996. The SVE
target area was evaluated to determine contaminant concentrations and whether the contaminants
present in the soil vapor could be effectively removed by the soil vapor extraction alternative
selected in the ROD.
The sample collectors were deployed at four locations within the SVE target area behind
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the fabrication building. Figure 3 shows the soil gas sampling locations. The collectors were
deployed on May 17, 1996 and retrieved on May 21, 1996. Analyses were performed on the
cartridges to quantify the concentration of five site-related contaminants: 1,1-dichJoroethane
(DCA), 1,1-dichloroethene (DCE), tetrachJoroethene (PCE), 1,1,1-trichJoroethane (TCA), and
trichJoroethene (TCE). Table 2 provides the quantitation levels for the constituents analyzed and
the soil-gas concentrations of the detected constituents.
Based on the analytical results of the soil-gas assessment, the following conclusions were
reached:
• Site-related volatile contaminants were detected in all four of the soil-gas samples
collected behind the fabrication building;
• The detection of site-related VOCs in the area behind the fabrication building is
consistent with previous analytical results of soil samples from the same area;
• The concentrations of individual soil-gas constituents were very low, ranging from
0.00000012 to 0.00000151 milligrams per liter (rog/1, or ppm); and
• The maximum total VOC concentration from a single sample location was 0.00000373
mg/1. SVE is more typically implemented when VOC concentrations are significantly
greater to effectively remove contaminants from the soil.
Hydrogeology and Groundwater Levels
A monitoring well, RI-2D, was installed within the OU3 source area during the RJ phase
of Site activity. Well logs for RI-2D indicate that the following lithologies were encountered
from the surface to the well's total depth of 38 feet: 0-1 feet, gravel pavement; 1-25 feet,
weathered, highly fractured gray sandstone, limestone, and quartz with voids at 18-20 feet; and,
25-38 feet, highly fractured sandstone, and limestone with quartz and fault breccia. Groundwater
was encountered at 3 feet in the weathered bedrock but the majority of water entering the well
was from a depth of 34 to 38 feet. The well was constructed as open-borehole from 28 to 38 feet.
A 6-inch steel isolation casing was grouted into place from 28 feet below the surface to about 2.5
feet above the surface.
Water levels in RJ-2D were measured on a few occasions since the well was constructed
in 1989. The water levels varied from about 5 feet below grade to a few inches below grade.
During 1996, all of the water levels were within 1.5 feet of the surface. Because SVE design
typically requires 5-10 feet of unsaturated conditions, the depth to water became a serious
concern for SVE implementation.
To further investigate the concerns for a shallow water table, a cone penetrometer (CPT)
was diverted from an onsite sinkhole investigation in August 1996, to evaluate conditions behind
the fabrication building. CPT testing was attempted in two locations behind the fabrication
building. Of the two test locations, the first encountered refusal about 1 foot below the ground
surface while the second test successfully penetrated to the desired depth of 5 feet below the
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surface. When the cone was removed from the second test hole, groundwater rose quickly in the
hole and stabilized at a depth of 14 inches. The water level remained constant for the 24-hour
period that the hole was left open. This indicates that the groundwater levels measured in the
well were similar to groundwater levels in the weathered bedrock adjacent to the well, and that
the SVE design would require modification, to include groundwater extraction and treatment, or
elimination of the remedial action.
Grouodwater Quality
Groundwater from monitoring well RI-2D was sampled in 1989, soon after well
completion. The analytical results are shown in the last column of Table 1. Since the
groundwater only contained a trace amount of VOC contamination, the well may not be
hydraulically connected to the subsurface path that water flows from the surface to the
groundwater, or water from roof drains and hillslope seeps in the area may have already
transported the contaminants into the groundwater and downgradient of the well. In either
situation, downgradient groundwater extraction wells, installed for Operable Unit 2, were
designed to collect and treat site-wide groundwater contamination, including contaminants
entering the subsurface behind the fabrication building.
SVE Pilot Study
In support of the selected remedial alternative, EPA prepared specifications for a soil
vapor extraction pilot study that would test the implementability of a full-scale system. This pilot
study would obtain information on the total quantity of volatile organics removed, treatment
system efficiency, and the need to proceed with full-scale SVE implementation.
Critical design assumptions for the SVE pilot study included:
• An unsaturated zone existed from the surface to approximately 5 feet below grade. This
zone would accommodate vapor extraction and vapor monitoring wells installed between
2.5- and 3.5-feet below grade.
• The quantity of water extracted with the SVE system would be kept to a minimum. A
separate groundwater pump and treat system would be installed downgradient of the SVE
target area to address contaminated groundwater, but it would not be available during the
SVE pilot study.
• The initial concentration of soil vapor constituents would be sufficiently high so that
removal of contaminants would be both measurable and supportive of the remedial action
objectives.
Based on a design vapor extraction rate of 20 cubic feet per minute, and a maximum
contaminant concentration of 0.00000373 mg/1, a SVE system would only recover a total of 3 mg
of contaminants per day (0.000007 Ibs/day). This rate is significantly lower than typical SVE
removal rates and would not be measurable during a SVE pilot study. Attachment A provides
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the annotated contaminant removal calculation.
Conclusions
Based on the information obtained from the analysis of soil and soil-gas samples, and the
physical characteristics of the area considered for soil vapor extraction, EPA has determined that
implementing the selected remedy for OU3 is not needed to protect human health, welfare, and
the environment. This BSD selects no further action as the remedial alternative for OU3.
During both surfkial soil sampling events in 1992 and 1995, the concentrations of VOC
contaminants identified for removal were already below the target cleanup level of 2 ppm as
specified in the Record of Decision. A subsequent pre-design investigation to evaluate the
subsurface soil-gas concentrations determined that contaminant levels were significantly below
the operating norm for a vapor extraction system, and that the amount of recoverable VOCs did
not warrant implementation.
Physical limitations in the area considered for vapor extraction also decreased the
applicability of such a SVE system. Weathered bedrock and groundwater were encountered less
than 1.5 feet below the surface. If a vapor extraction system were implemented under these
conditions, excessive amounts of water wouJd be generated, and treatment costs would increase
significantly. Also, since groundwater is being collected downgradient of the intended SVE area
for OU2, and the VOC concentrations in the groundwater from monitoring well RI-2D were
negligible, recovery of groundwater in the SVE area is not warranted.
Since site conditions and contaminant levels in the SVE target area have changed
significantly from the pre-ROD conditions, the selected remedial alternative for OU3 is no longer
appropriate or warranted.
FV. Support Agency Comments
EPA is the lead agency for Site activities and PADEP is the support agency for the Site.
PADEP was provided with a copy of the proposed ESD, and provided its concurrence in a letter
dated August 31,1998. PADEP was provided a copy of the revised technical report
summarizing the investigations, and had no comments as noted in a letter dated April 4,1997.
VI. Affirmation of the Statutory Determinations
EPA believes that the ESD remedy (Alternative 1) is protective of human health and the
environment, and complies with Federal and State applicable or relevant and appropriate
requirements for this action.
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VIII. Signature
U.S. ENVIRONMENTAL PROTECTION AGENCY
Date Abraham Ferdas, Director
Hazardous Site Cleanup Division
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Figures
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NMtterln4 ••11
1 Otrie* talldlng
Source: Drift RU989
Figure 1
Site Map
CryoCbera Inc
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SCALE NOT PROVDCO
Source: Motfftod rrom JACA, 1990
Figure 2
APPROXIMATE AREA PI
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Cone Penctrometer Test Points
Soil Gas Sample Points
Monitoring Well RI-2D
Sleep Bank (approx. location)
\\\\\\\\\\\\\\\\u\\«\\\\\\\\\\\\\\\\\\\\\\\\\\\u\\\\\\\\\\\\\\u\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
SO-3
SG-4
Cinder Block Walled Area
SO 2 • , S°"'
»*
Safety Storage
^ SI A -Advanced to 5* BOS
Oroundwater 9 M"
, , j 1 "^ Spray Booth
II II
Door I
Fabrication Building
Door2
SCALE r- 20'
Figure 3
Soil Gas and Cone Penelrometer Test Locations
CryoChem Inc.
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Tables
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Table 1
Soil and Groundwater Sampling Results Behind the Fabrication Building
CryoChem Inc. • Operable Unit 3
Contaminant
Identified lor
Removal
1.1.1-TCA
TCE
PCE
1.1-OCA
Ethytoenzene
Xytene
Methytene Chloride
Maximum
AlowableSoi
Concentrations'
26
0.53
2
88
654
2.020
Soils
Rl
January 1989
Loci 16 Loci 17
0.019 22
0.001 0.6
0.053 0.46
ND 4
0.92
ND 11
CH2M HILL
November 1992
Loc»13 Loc*17tof22 Loc *18
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
0.047 0.004 J 0.029
June 1995
Loc«13 f13DUP Loc 117 Loc §22 Loci 18
0.166 0.081 0.0006 J ND ND
ND ND ND ND ND
ND 0.003 J ND ND ND
0.092 0.056 ND ND ND
ND ND ND NO ND
ND ND ND ND ND
0.003 J 0.002 J 0.002 J 0.002 J 0.002 J
Groundwater
Rl
May 1989
RI-2D*
NO
0.001 J
ND
ND
ND
ND
ND
Notes:
AH concentrations In mo/kg (parts per million).
* : Summers Model calculations presented In the ROD. based on Rl sampling data and MCLs
ND : Non-Detect
J: Contaminant present. Reported value Is estimated, because concentration to outside range, lor accurate quantHation.
" : RI-2D Is the groundwaler monitoring well within the SVE Target Area. This analytical result is lor the only groundwaler sample collected at this wed.
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Table 2
Soil-Gas Concentrations (mg/I)
CryoChem Inc. - Operable Unit 3
SAMPLE
LOCATION
CONTAMINANTS
1 , 1 -Die hi oroe thane
1,1-Dichloroethenc
TetrachJoroethene
1,1,1-TrichJoroe thane
Trichloroethene
Q.L.
0.0000017
0.0000009
0.0000009
0.0000014
0.0000010
1
0.00000078
0.00000131
0.00000013
0.00000151
ND
2
0.00000070
ND
0.00000024
0.00000046
ND
3
ND
ND
0.00000012
0.00000031
ND
4
ND
0.00000037
0.00000025
0.00000026
0.00000022
NOTES:
Contaminant concentrations provided in mg/1 (ppm).
1) Values listed under "Q.L" are reported soil-gas concentration quantitation levels.
2) "ND" denotes contaminant not detected at the reported quantitation level.
3) While 1,1,1-Trichloroethane was targeted in this survey, it is important to note that
this compound co-elutes with Carbon TetrachJoride. Therefore the two cannot be
distinguished.
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Attachment A
Soil Gas Contaminant-Removal Calculations
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Attachment A
CryoChem Inc. Site - Operable Unit 3
Soil Gas Contaminant Removal Calculation
Assumptions:
SVE Extraction Rate * 20 cubic feet per minute (CFM)
1 cubic foot > 28.32 liters
1 cubic foot/minute « 0.472 liters/second
1 milligram «= 0.0000022 pounds
Maximum Contaminant Concentration = 0.00000373 mg/l (Soil gas sample location 1)
Calculations:
Vacuum Rate Conversion
O 1 CFM Factor
0.472 Us x 86,400 s/day « 40,781 L/day
Volume of Air Extracted
Dairy
815.620 L/dav 020 CFM
So/7 Gas
Volume Extracted
Daily
Maximum
Contaminant
Concentration
815,620 IVday x 0.00000373 mg/L « 3 mg/day
Anticipated
Contaminant
Removal Pate
3 mo/day
O.QQ0007 Ibs/dav
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