PB94-963920
EPA/ROD/R03-94/183
October 1994
EPA Superfund
Record of Decision:
North Penn Area 1 Site,
Souderton, PA,
9/30/1994
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Declaration for the Record of Decision
Site Name and Location
North Perm Area 1 Site
Source Control Remedial Action—Operable Unit 1 (OU1)
Ground Water Interim Remedial Action—Operable Unit 2 (OU2)
Souderton, Montgomery County, Pennsylvania
Statement of Basis and Purpose
This decision document presents the selected remedial action
for contaminated soil and the selected interim action for ground
water contamination at the North Perm Area 1 site in Souderton,
Montgomery County, Pennsylvania. These remedial actions were
chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA) and, to
the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision document explains
the factual and legal basis for selecting the remedies for Operable
Units 1 and 2. This decision is based on the administrative record
for this Site. \
The Pennsylvania Department of Environmental Resources has not
indicated whether or not it concurs with the selected remedy.
Assessment of the Site
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
selected in this Record of Decision (ROD), may present an imminent
and substantial endangerment to public health, welfare, or the
environment.
Description of the Selected Remedy
Alternative 3 for soil contamination (Excavation and Offsite
Disposal) and a combination of Alternatives 4 and 5 for ground
water contamination (Pumping and Treating of the upper interval of
the Granite Knitting Mills well and the entire Well S-9), are the
selected remedies for the Site.
Alternative 3 for source control will involve the excavation
of contaminated soils at each of three properties. The soil would
be shipped to an EPA-approved facility for disposal. The
remediation goals were developed for each property by evaluating
the concentration of contaminants, the depth to ground water, the
subsurface conditions, and other factors. The performance
standards for remediating the soils, and tlu* estimated quantity of
soils needing to be removed for each property, are:
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PCE Soil
Property Remediation Goal Estimated Quantity
Gentle Cleaners 270 ppb 115 cubic yds.
Granite.Knitting Hills 260 ppb 400 cubic yds.
Parkside Apartments 820 ppb 95 cubic yds.
Implementation of Alternative 3 for the soil contamination
operable unit will remove any threat of direct contact exposure,
and will also improve ground water quality by eliminating a
continuing source of contamination. Once the contaminated soil is
removed, the levels of PCE entering the drinking water aquifer
should be significantly reduced.
The selected interim action alternative for the ground water
operable ~ unit is a combination of Alternatives 4 and 5.
Alternative 4 consists of pumping just the upper interval (the top
30 to 40 feet) of the Granite Knitting Mills well. Alternative 5
involves pumping of the entire Well S-9. The combination of
pumping both of these wells addresses the high levels of PCE
entering the aquifer from the shallow zone in the area around the
GKH well, and the PCE contamination that has already reached the
aquifer in the vicinity of Well S-9. Due to the central location
of well S-9, pumping it is expected to contain the plume and draw
contaminated water from throughout the plume area. :
Statutory Determinations
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action (or a waiver can be justified for any federal and state
applicable or relevant and appropriate requirements that will not
be met) and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable, and it satisfies
the statutory preference for remedies that employ treatment that
reduce toxicity, mobility, or volume as their principal element.
Because this remedy will result in hazardous substances
remaining on Site above health-based levels, a review will be
conducted within five years after commencement of remedial action
to ensure that the remedy continues to provide adequate protection
of human health and the environment. Such reviews will be
conducted every five years thereafter until EPA determines that the
cleanup levels set forth in this ROD have been achieved, or that
the hazardous substances remaining on the Site do not prevent
unlimited use and unrestricted exposure at the Site.
Kosfemayer. Date
rional Administrator
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North Penn Area l site
Souderton, PA
operable Units l and 2
1. Site Name. Location, and Description
Source control Operable Unit - Remedial Action
Ground Water Operable Unit - Interim Action
Souderton, Montgomery County, Pennsylvania
This Record of Decision (ROD) describes the selection of the
remedial action plan to address the sources of contamination at
the North Penn Area 1 Site. This ROD primarily addresses the
source of contamination at the Site (contaminated soil), but also
includes an interim action to address ground water contamination.
The source control remedial action has been designated as
Operable Unit 1 (OU1), and the ground water contamination
remedial action has been designated as operable unit 2 (0172) for
purposes of organizing and identifying remedial actions at this
Site. — -
This Site is located in Souderton, Montgomery County, ",
Pennsylvania, and is one of 12 Sites identified in the North Penn
area on the basis of contamination of ground water by volatile
organic compounds (VOCs) in production wells. The contamination
at the Area 1 Site was first noted in 1979 in North Penn Water
Authority (NPWA) well S-9. The well was immediately taken out of
service because of the high tetrachloroethylene levels in the
ground water. (Tetrachloroethylene is also known as
perchloroethene, which is abbreviated as PCE. The term PCE is
used in this document, except in the charts where
tetrachloroethylene is used). On the basis of this
contamination, the Site was proposed for the National Priorities
List (NPL) in January 1987, and was placed on the NPL in March
1989.
The Site is located in an area that contains a mixture of
commercial and residential uses. All residences within the
immediate area use public drinking water supplies. The nearest
known downgradient well currently in use for drinking water
supplies is approximately 1/2 mile away. There is a park located
just south of the plume area. The boundaries of the Site are
shown in Figure 1.
After the contamination was identified, potentially
responsible party (PRP) searches by EPA identified five
facilities in the area that may have contributed to the ground
water contamination. These facilities and the ground water
contamination were evaluated in the Remedial
Investigation/Feasibility Study (RI/FS) that forms the basis for
this ROD. The results of the sampling work done during the RI/FS
revealed that contamination exists at three of the five
properties.
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The Site currently consists of the three facilities
identified as potential source areas and the bedrock aquifer
containing VOC contamination underlying and in the vicinity of
those facilities. The three facilities that may have contributed
contamination to the ground water are: Gentle Cleaners, Granite
Knitting Mills, and Parkside Apartments. Locations of the
facilities are shown in Figure 1. Figure 1 also shows the
dimensions of the Site based on the locations of the facilities
and the approximate distribution of contaminated ground water in
the bedrock aquifer.
2. Site History and Enforcement Activities
After the identification of contamination in the ground
water in the area in 1979, the NPWA initiated an investigation
into the source or sources of the contamination. EPA and the
Pennsylvania Department of Environmental Resources (PADER) were
notified of the contamination, and over the next several years
were involved in investigating the sources.
Sampling was conducted at several wells in the area, to
determine the types and levels of contamination in the ground
water. The following contaminants were identified: ",
- 1,1,1-Trichloroethane (1,1,1-TCA)
- 1,1-Dichloroethane (1.1-DCA)
- 1,1-Dichloroethene (1.1-DCE)
- cis- and trans-l,2-Dichloroethene (1,2-DCE)
- Tetrachloroethylene (PCE)
- Trichloroethene (TCE)
These contaminants were found in several wells at various
times at levels up to 250 parts per billion (ppb).
The following paragraphs discuss the history of each of the
properties identified as potential sources of the contamination.
Gentle Cleaners began operating before 1953. It is known that
between 1953 and 1983, the company used 70 to 100 gallons of PCE
per month .as well as almost 1 gallon per month of chemicals
containing 1,1,i-trichloroethane (1,1,1-TCA) and other
chlorinated solvents of unknown composition. Since 1983, the
volume of PCE used has been reduced to about 50 gallons per
month. The PCE was stored onsite in either an aboveground
storage tank or drums. An underground storage tank (UST) also
may have been used to store PCE at the facility.
On July 23, 1980, EPA documented a spill of 75 gallons of
PCE occurring in the early 1970s. PCE reportedly flowed out the
rear door onto the grassed area behind the building. In
addition, discharge of PCE to a sink that drained into the same
grassed area may have contributed to soil contamination.
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SOURCE: U. S. GEOLOGICAL SURVEY 7-1/2 MINUTE QUADRANGLE MAP FOR TELFORO. PA.
LEGEND
A
S-2
A
GKM
NPWA WELL (Water supply wells)
GRANITE KNITTING MILLS WELL
BOROUGH AND TOWNSHIP
BOUNDARIES
PRELIMINARY BOUNDARY OF
AREA 1 (NUS. W6a)
FACILITY UNDER STUDY
600 7200 WOO
SCALE: r*J2QQr
SITE MAP
North P«nn ATM t
FIGURE X
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Granite Knitting Mills (GKM) has operated a knitting mill
since the early 1960s. From 1967 to 1979, a dry cleaning machine
using PCE was maintained at the facility. Use of the machine'may
have stopped by 1979. PCE for the machine was stored in a tank
inside the building. Wastes generated from the machine were
estimated to contain about 2 percent PCE and were stored in drums
inside on the southwest side of the building. . .1
Property owners in the area report past discharges from the
facility into the alley that runs along the southeast side of the
building. These discharges were variously described as solvents
and dyes, but their point of origin along the building was not
identified. Reportedly, drums containing waste oil with- some
solvent contamination were stored outside along the southwest
side of the building prior to disposal. . . —
The Parkside Apartments property once included'a dry
cleaning establishment. Before that, the property was used as a
beer distributor, and before that, as a slaughterhouse. Three
USTs containing petroleum hydrocarbon fuels were once located on
the property, but were allegedly removed around 1980. Another
UST that may have been present at the south corner of the
facility could not be located during EPA's onsite activities. *
Area residents reported that part of the facility -may have been -.
landfilled with dirt and construction debris. !
Lexco Engineering and Manufacturing Corporation (Lexco) has
used 1,1,1-TCA at its facility since 1979. The facility
purchases 110 gallons annually and generates 10 gallons as waste
annually. The 1,1,1-TCA is used in a trough and may have spilled
or leaked onto the floor. Operations at the facility have been
ongoing since before 1960 (Logan Deposition, 1991). The facility
uses one UST for oil storage. A second UST in which gasoline was
stored is located along the side of the building but is no longer
in service.
•The former Standard Terry Mills building previously was
occupied by a trolley repair shop, supermarket, gas station,
knitting mill, and other activities. These operations could have
used solvents and chemicals and may have contributed to local
groundwater contamination.
The former Standard Terry Mills facility was in operation
until May 1991, when a fire occurred at the facility; the
buildings were later razed. The facility has undergone a Phase I
property assessment, during which the site was primarily
evaluated for polychlorinated biphenyl contamination; a report
indicated that the facility was uncontaminated. Two USTs were
identified at the facility. The current owner of the property
reported that one UST was removed about 7 years ago and that two
fuel oil tanks were removed around January 1991.
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On February 28, 1990, EPA issued general notice letters to
the owners and/or operators of the five properties pursuant to
Section 107 (a) of CERCLA, to inform them of their potential
Superfund liability as operators or owners of the properties. On
May 20, 1991, EPA again notified the owners and/or operators of
these properties of their potential liability for this Site.
After several discussions with them concerning the nature and
extent of EPA's work to be performed, the owners or operators of
the properties indicated that they were not willing and/or able
to perform or finance Operable Unit 1 to prevent a release or
threatened release of hazardous substances, pollutants, or
contaminants from the facility. Therefore, EPA decided to
perform the response at Operable Unit 1 with funds from the
Hazardous Substance Superfund as authorized by Section 104 of
CERCLA, 42 U.S.C. S 7604.
In August, 1991, EPA initiated the RI/FS for this Site. EPA
performed investigations that included soil boring, soil sampling
and analysis, aquifer testing, and ground water sampling and
analysis. The soil sampling defined soil characteristics and
levels of soil contamination by VOCs at the facilities. The
aquifer testing characterized aquifer hydraulics and provided
information needed to evaluate remedial options. The ground ;
water sampling defined the nature and extent of the VOC contain!-r
nation in the bedrock aquifer at the Site to the extent possible
using existing wells; no monitoring wells were installed during
the investigations. The results of the RI/FS are further
described in Section 5.
3. Highlights of Community Participation
The EPA issued the Proposed Plan for this Site for public
comment on July 6, 1994. The RI/FS report, summarized in the
Proposed Plan, was also made available to the public. EPA
published a notice of availability of these two documents in the
North Penn Reporter on July 5, 1994. These and other Site-
related documents were made available to the public in both the
administrative record file and an information repository
maintained at the EPA Docket Room in Region III and at the
Indian Valley Public Library in Telford, PA.
In accordance with Sections 113 (k) (2) (B) (i-v) and 117 of
CERCLA, 42 U.S.C. SS 9613 (k) (2) (B) (i-v) and 9617, EPA held a
public comment period from July 6, 1994 through August 4, 1994.
In addition, EPA held a public meeting on July 14, 1994 at the
Souderton Municipal Building. Both the public comment period and
the meeting were also announced in the notice of availability,
and again on a notice on July. 13, 1994. At this meeting, EPA
presented the proposed plan, answered questions, and received
comments. A response to the comments received during the public
comment period is included in the Responsiveness Summary, which
is attached as part of this Record of Decision.
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This decision document presents the selected final remedial
action for operable unit 1 of the North Penn Area l Site in
Souderton, Montgomery County, Pennsylvania, and presents the
interim remedial action for operable unit 2 of the Site, chosen
in accordance with CERCLA, as amended by. SARA, and to the extent
practicable, the National Contingency Plan. The decision for
this Site is based on the Administrative Record.
4. Scope and Role of Operable Units 1 & 2 Within Site Strategy
The remedial work at this Site has been divided into two
separate planned remedial actions. The first operable unit is
the source control operable unit (OU1) . This Record of Decision
(ROD) selects a final remedial action for OU1, which 'addresses
the soil contamination that is contributing to ground water
contamination. The second operable unit (OU2) is for ground
water contamination. This ROD also selects an interim action to
protect ground water. EPA will select a final remedial action
for OU2 at a later date. .
This ROD describes EPA's selection of the remedy for the
soil contamination, and an interim remedy for the ground water
treatment. Organic solvents (primarily PCE) were used in *
commercial operations over varying periods of time at each ^
property, and is still being used at Gentle Cleaners. . Through ;-
spills or discharges, these solvents contaminated the soils
beneath the properties, and eventually migrated to the ground
water. EPA and others have measured contamination in the ground
water that exceeds the levels established in the Safe Drinking
Water Act for public water supplies. Continued migration of the
contamination remaining in the soil could exacerbate the ground
water contamination problem, and could also result in direct
exposure to anyone excavating the soil in the areas of
contamination.
As described in the Proposed Plan, the remedial action
objectives of this action are to remove the potential exposure
risk from the contaminated soil, to eliminate the source of
contamination migrating to ground water, and to prevent the
spread of contaminated ground water.
of Site Characteristics
EPA completed a Remedial Investigation/Feasibility Study
(RI/FS) for OU1 and OU2 at the Site in June 1994. The purposes
of the RI/FS were to:
- Characterize the hydrogeology of the Site, particularly
with respect to the location and orientations of water-
bearing fractures and the directions of ground water flow.
AR30U53
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- Define the nature and extent of contamination in ground
water and soil, and define the Site boundaries.
• Determine which of the five identified properties
contributed to the ground water contamination by identifying
those properties with soil contamination -
• Identify sources of contamination, including contaminated
soil and underground storage tanks at the PRP facilities,
and identify the nature and concentration of chemicals
present at these sources.
— Identify the nature of contaminant migration at the Site,
including pathways related to soil and ground water.
- Perform a risk assessment to evaluate any potential threat
to human health and the environment.
- Evaluate potential interim action operable units to reduce
contaminant migration and threats to human health and the
environment.
<.
- Develop and evaluate a range of final (for OU1) and •
interim (for OU2) remedial action alternatives to control 7
any identified human health or environmental threats. ;
During the remedial investigation (RI) activities at the
Site, EPA investigated the nature and extent of soil and ground
water contamination by volatile organic compounds (VOCs). The
results of the investigation are presented in this section.
The Site is in an area with a gently rolling topography,
with low-lying ridges and hills. Most of the surface runoff in
the area drains to the Schuylkill River, which flows into the
Delaware River. The bedrock in this area is mostly reddish-brown
shale interbedded with mudstone and siltstone. The bedrock is
generally found from 5 to 15 feet below the ground surface, and
the water table is between 5 and 20 feet below the top of the
bedrock. In the immediate area of the site (along Green Street),
the land slopes gently from the northeast to the southwest. Due
to the topography and bedrock conditions, the ground water flow
in the immediate area follows the slope of the surface (to the
southwest).
Soils
The nature and extent of VOC contamination in soils at each
of the five facilities were investigated to determine if any of
the facilities may have been sources of contamination to the
ground water and whether any of the facilities may continue to be
sources. Soil samples were collected from soil borings at 2-foot
intervals until bedrock was reached, and these samples were
screened with an HNU photoionization detector (PID). Soil
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samples selected on the basis of the appearance and odor of the
soil were analyzed in the field with a portable gas chromatograph
(GC) in a close support laboratory (CSL). A smaller number of
soil samples were sent for analysis through the EPA Contract
Laboratory Program (CLP). The soil samples sent through the CLP
program were selected to provide information on the areal extent
of contamination at the facility and to quantify levels of
contamination at the facility for use in the risk assessment.
For two of facilities, no significant contamination .-was
found. At Lexco, no volatile contamination was found.. At the
former Standard Terry property, one sample result indicated an
estimated value for PCE of 7 ppb. No other samples at. this site
revealed any volatile contamination. Therefore, these two •
properties will not be discussed further. For the remaining
three sites, the results of the field GC analyses of the soil
samples are presented in Table 1. Validated results of the CLP
analyses of selected samples are summarized in Table 2. The
complete results of the analyses are provided in the RI/FS
report.
Acetone and methylene chloride were detected in most of the
samples sent to the CLP. The presence of these VOCs was believed
to be the result of contamination in the analytical procedures, as
demonstrated by detection of these compounds in the associated- i
method blanks. All of the soil samples sent to the CLP contained
one or both of these chemicals, even those samples from
facilities where no other contaminants were detected.
a. Gentle Cleaners
At Gentle Cleaners, soil samples were collected from eight
soil borings. Eleven soil samples, were analyzed with the field
GC for VOCs. Five of these samples and one duplicate were then
sent through the CLP for analysis for VOCs and total organic
compounds (TOCs).
The chemical analyses indicated that PCE is the primary
contaminant at this facility. The soil boring locations and
field GC results for PCE are shown in Figure 2, and the PCE
results of the CLP-analyzed samples are presented in Figure 3.
The highest concentrations of PCE were detected in samples from
the 6- to 10-foot interval in the backyard of Gentle Cleaners.
One of these samples was sent to the CLP and contained a PCE
concentration of 300,000 micrograms per kilogram (fig/kg or parts
per billion). This sample exceeded the detection limits of the
field GC, as did a sample from boring GC-7; this exceedance is
indicated by the term "off scale11 in the figure. The highest
concentration of PCE in a soil sample obtained from the yard next
to Gentle Cleaners was from boring GC3, the nearest boring to the
stone wall separating the two properties. Concentrations were
low or below detection limits in surface soils at this facility.
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TCE was detected by the field GC at 1 Mg/kg In one sample in
the 8- to 10-foot interval at boring GC6-but none was detected in
samples sent to the CLP. No other VOCs were detected in soil
samples by the field GC.
A leaf-sample was collected from the GC-7 location when it
was noticed that the leaves had a strong solvent smell, and VOCs
registered strongly on the HNU, The sample was analyzed using
the field GC. No PCE was detected in the sample but several
compounds not identifiable by the field GC were present.
Contaminant levels found in soils during this investigation
suggest that the extent of soil contamination at this facility is
limited. The highest levels were found behind the cleaners, and
some elevated levels were found in the adjoining yard. But no
VOCs were detected in soil samples taken south of the cleaners,
at borings GCl and GC2, along a probable path of contaminant
migration, down the gentle slope of the yard. Access limitations
prevented obtaining samples southwest and west of the cleaners.
The concentration of 300,000 pg/kg of PCE detected in one
sample at this facility appears to be the result of the spill of,
75 gallons of PCE that reportedly occurred at this facility.
This liquid would have seeped down into the soil and would have i
been adsorbed to some degree onto the soil particles.
b. Granite Knitting Mills
The EPA investigated soil contamination at Granite Knitting
Mills by drilling 14 soil borings and collecting samples from
various depths within each boring. All of the soil borings were
drilled through asphalt cover and the underlying soils to the top
of bedrock. Twenty-four soil samples were analyzed with the
field GC, and eight samples were sent to the CLP.
The results of the field GC data indicate that the
contaminants in the soils associated with this facility were
primarily PCE. The soil boring locations and field GC sampling
results for PCE are presented in Figure 4. Selected samples were
sent through the EPA CLP program for analysis and documentation.
The PCE results of the CLP sampling are presented in Figure 5.
Boring GKH-12 is not shown in either Figure 4 or 5. Boring
GKM-12 is located in the alley at the northeast corner of the
mills property (off of the map on the right-hand side) to help
determine if any contamination was moving down the hill from
Gentle Cleaners and running into the alley. Soil samples were
collected to auger refusal at.4 feet below the surface. The
2-to-4 foot sample was analyzed by the field GC and through the
CLP. The field GC detected PCE at 2 pg/kg. The CLP sample had a
detection limit of 11 pg/kg and did not detect PCE in the sample.
8
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TABLE 1
NORTH PENN AREA 1 SOIL ANALYSIS
FIELD GC RESULTS Page 1
Sample
Identification
Depth
(feet)
Detected Compounds
Concentrations
0*g/k£)
GRANITE KNITTING MILLS
GKM2-S2
GKM2-S5
GKM1-S4
GKM1-S3
GKM1-S1
GKM6-S4
GKM6-S4D
GKM5-S5
GKM6-S6
GKM5-S3
GKM5-S4
GKM4-S3
GKM7-S3
GKM10-S2
GKM3-S2
GKM3-S4
GKM8-S4
2-4
8-10
6-8
4-6
0-2
6-8
6-8
8-10
10-12
4-6
6-8
4-6
4-6
2-4
2-4
6-8
6-8
Tetrachloroethylene
Tetrachloroethylene
ND * ,
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
f
Tetrachloroethylene
Tetrachloroethylene
cis-l,2-Dichloroethylene
Trichloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
ND
Trans-l,2-Dichloroethylene
cis-l^-Didhloroethylene
Trichloroethylene
Tetrachloroethylene
19
152
4
3
45
37
4
4
9
10
32
22
52
7
15
6
175
7
53
off-scale
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TABLE 1
NORTH PENN AREA 1 SOIL ANALYSIS
FIELD GC RESULTS Page 2
Sample
Identification
GKM14-S1
GKM14-S2
GKM11-S1
GKM13-S1
GKM12-S2
GKM11-S2
GKM12-S1
GKM Storm Drain
Depth
(feet)
0-2
2-4
0-2
0-2
2-4
2-4
0-2
0-1
Detected Compounds
ND
ND
ND
Trichloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene •,
ND
ND
Concentrations
0*g/kg) .
4
582
2
1
GENTLE CLEANERS
GC5-S1
GC3-S3
GC7-S2
GC7-S4
GC1-S2
GC6-S5
GC4-S1
GC8-S3
GC2-S1
GC6-S6
GC8-S2
GC-TS
0-2
4-6
2-4
6-8
2-4
8-10
0-2
4-6
0-2
10-12
2-4
04.5
ND
Tetrachloroethylene
ND
Tetrachloroethylene
Tetrachloroethylene
Trichloroethylene
Tetrachloroethylene
ND
Tetrachloroethylene
ND
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroetbylene
1449
off-scale
2
1
off-scale
73
28
53
5
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TABLE 1
NORTH PENN AREA 1 SOIL ANALYSIS
FIELD GC RESULTS Page 3
Sample
Identification
Depth
(feet)
Detected Compounds
Concentrations
0»g/kg)
PARKSEDE APARTMENTS
PA2-S2
-
PA3-S2
PA8-S4
PA4-S3
PA5-S3
PA7-S6
PA6-S4
PA7-S3
PA10-S2
PA9-S3
PA5-S2
PA8-S1
2-4
2-4
6-8
4-6
4-6
10-12
6-8
4-6
2-4
4-6
2-4
0-2
Trans-l,2-Dichloroethylene
cis-l,2-Dich]oroethy]ene
TrichJoroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
cis-l,2-Dichloroethylene
Trichloroethylene
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
Trichloroethylene
Tetrachloroethylene
Tetrachloroethylene
ND
Tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene
0
16
50
193
3
5
7
5
160
21
23
4
1787
5
17
32
3
NOTE: ND = None detected.
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Table 2
ANALYSES OF ORGANIC COMPOUNDS IN SOILS
CLP RESULTS
Centk Cteanen
Sample No.
Depth (ft)
Compound
1,2-DCA Otgftg)
MEKO*/kg)
Acetone (pg/kg) •
MC<>ig/kg)
PCEO*g/kg)
Toluene Gtg/fcg)
TCE Gig/kg)
TOC (mg/kg)
Sample No.
Depth (ft)
Compound
1,2-DCA fcig/kg)
MEKOig/kg)
Acetone (pig/kg)
MCfcig/kg) .
PCEG*g/kg)
Toluene (pg/kg)
TCE(«*g)
TOC (mg/kg)
GKM-3
2-4
<12
17 B
25 B
12 B
<12
<12
<12
766
GC-3
4-6
<13
<13
43 B
17 B
100
<13
<13
1,490
GC-5
0-2
<12
<12
12 B
18 B
23 J
<12
<12
2,450
GC-6
8-10
-------
Table 3
ANALYSES OF ORGANIC COMPOUNDS IN SOILS
CLP RESULTS
Pwfcsldc Apwtmc&ls
Sample Na
Depth (ft)
CocDpouod
l^DCAOig/kg)
MEK<«/kg)
Acetone (pg/kg)
MCOi«/kg)
PCECM«/kg)
Toluene (pg/kg)
TCE(/
-------
STONE WALL
x
NO
AU. UNITS
FIGURE 2
PCE CONCENTRATIONS
FROM FIELD GC ANALYSES
GENTLE CLEANERS
North pom ATM 1
Phase n RI/FS
flR30|i*62
-------
\
\
X
GO-I
X
GO-2
x S
X
QC-4
STONEWALL
I 'A
^
2,
oo-e
*s\
DISCHARGE HOLE « AIR VENT
'//////////////////j,
#
STONEWALL
LEGEND
y SOIL BORING
* LOCATIONS
ND NOT DblbClhO
ALL UNITS m >«Ag
j VALUE ESTIMATED
BELOW DETECTION LIMIT
PCE CONCENTRATIONS
FROM CLP ANALYSES
GENTLE CLEANERS
North Pwn ATM 1
RI/FS
FZGURB 3
AR30U63
-------
/
GRANITE
KNITTING
MILLS
3D
CO
O
LEGEND
(OR. BORMO
LOCATIONS
NOT .DETtCIfO
AU. u<{Tt
FIOURB 4
PCE CONCENTRATIONS
FROM FIELD QC ANALYSES
GRANITE KNITTING MILLS .
Norn Pmn ATM 1 ;
-------
CO
CD
•IT
cr»
en
I
/:
1
i#f
'#
OKHht
II
MM
ON»
*
tt»-M
OMM
]FK!s"-tt*
/ «"»««
• — i
^-'
I
SS-*1
tMCftWAsrr
Ml JTOBAOE AWA
GRANITE
KNITTINO
MILLS
^P^-ryyi
|
?///
T) rwi
1
00M
*
\
'A gg»«
X/^ OOOWAK
/////Jh////////////
«raw amn OMTC
LEQEND
M>
. VMM IfTMAItQ
J BBXm Of ItCTlOM LMIT
PCE CONCENTRATIONS
FROM CLP ANALYSES
GRANITE KNITTING MILLS
North Pern ATM 1 : •
-------
The highest concentration of detected PCE at the facility
was at boring GKM-8; 6,900 jig/kg were detected by the CLP, and
the sample exceeded the field GC detection limit. Most other
concentrations were low, except at boring GKM-13, where 1,000
/jg/kg of PCE were detected in the surface sample (below asphalt)
by the CLP. This location is near a storm sewer grate,
suggesting the possibility that contamination may move into the
storm sewer with surface runoff. No VOCs were detected in a
sample of soil obtained from the northern storm drain and
analyzed by the field GC (sample GKM storm drain).
Surface water samples were collected from the unnamed
tributary to Skippack Creek below the outfall of this storm sewer
when it was discharging. The surface water samples were analyzed
with the field GC, and no VOCs were detected.
-; The soil samples collected from the former solvent storage
area (along the southwest side of the building) found PCE levels
varying from not detected to 152 pg/kg. The PCE levels found in
boring GKM-8 were significantly higher.
Other VOCs were detected by the field GC and the CLP: cis-
1,2-DCE (two detections), trans-l,2-DCE (one detection), 1,2-DCA
(one detection), methyl ethyl ketone (one detection), toluene ;
(two detections), and TCE (three detections). The highest levels
of most of these other VOCs were detected by the field GC in the
6- to 8-foot sample from GKM-8; trans-l,2-DCE at 175 jig/kg, cis-
1,2-DCE at 7 Mg/kg, and TCE at 53 Mg/kg; 1,2-DCA also was
detected at 45 ng/Kg by the CLP. The two other field GC
detections of other VOCs were below 5 fig/kg. Acetone and
methylene chloride also were reported as being detected by the
CLP in all of the samples. (As noted above, these are believed
to be due to contamination introduced in the lab or sample
containers.)
The results of soil analyses for VOCs at this facility
suggest that the highest levels of contamination are restricted
to the southeast side of the building. The highest level of
contamination in this area was found at the interval from 6 to 8
feet. Concentrations at the surface were low to nondetectable.
o. Parkside Apartments
EPA investigated the Parkside Apartments facility by
drilling and sampling of 10 soil borings in the lawn behind the
building. Twelve selected soil samples were analyzed in the
field using a field GC. Six samples and one duplicate were then -
sent through the CLP. On the basis of the known past property
use, EPA located the soil borings to provide coverage of the area
where contamination may have occurred.
-------
The analyses of the soil samples found contamination to be
primarily PCE. The results of the field GC analyses for PCE are
presented in Figure 6. The results of the CLP analyses for PCE
are presented in Figure 7. The levels of PCE observed ranged
from not detected to 1,787 Mg/kg on the field GC, and not
detected to.120 pg/kg in the CLP data. The highest levels of PCE
were located next to the building at borings PA-2, PA-4, and PA-
.6. Away from the building, the levels of PCE were much lower.
Cis-l,2-DCE (two detections), trans-l,2-DCE (one detection),
TCE (three detections), and 1,2-DCA (one detection) also were
detected at the facility. All of these other VOC detections were
in samples obtained from borings PA-2, PA-4, and PA-6, next to
the building. The highest concentration of TCE detected was 50
Mg/kg in a 2- to 4-foot sample in boring PA-2. Acetone and
methylene chloride also were reported as being detected by the
CLP in most of the samples. (As noted above, these are believed
to be due to contamination introduced in the lab or sample
containers.)
Ground Water
VOCs, particularly PCE and TCE, have been detected in ground
water at the Site. The ground water was sampled during the RI at
several wells in and near the Site. The wells sampled during
this investigation met one or more of the following criteria:
• They were identified during the well inventory as
drilled wells.
• They had contaminants detected in previous
investigations at the Site.
• They are currently used as drinking water supply wells.
• They are located within 1/2 mile of the Site
boundaries.
• The owner allowed them to be sampled.
The results of the ground water sampling and CLP analyses
are presented in Table 3 and in Figure 8. The complete results
of CLP analyses are presented in the RI/FS report. The highest
levels of contamination occur in the wells at the center of the
Site, including the GKM well, NPWA wells S-9 and S-10, and the
Souderton Borough well (well 679), which had PCE concentrations
ranging from less than 1 to 5 micrograms per liter (pg/1 or parts
per billion). The only other bedrock well exhibiting detectable
levels of PCE was residential well R-2, with a concentration of
0.1 pg/1.
The greatest variety of contaminants was detected in the GKM
well, followed by the well at the Mennonite Home for the Aged
(well R-10). The fact that the well at the Home did not contain
PCE and had some other differences in the make-up of the VOCs
10
AR30U67
-------
UNNAMED TROUTAff OF SKIPPAOK CREEK
WOODS
WOODS
-STONEWALL
LEGEND
SOU. BORING
LOCATIONS
NO
NOT
AU. UNITS IN >jg/kg
FIGURE 6
PCE CONCENTRATIONS
FROM FIELD GC ANALYSES
PARKSIDE APARTMENTS
North Pern Area 1
AR30U68
-------
UNNAMED TR/a/TAW OF SK/PPACK CREEK
job
58
PA-7
x
\ftESJLTS i
WOCDS
I20J I CT-g
WOODS
STONE WAU.
LEGEND
x
NO
SOIL BORING
LOCATIONS
NOT DETECTED
ALL UNITS IN >jg/kg
VALUE ESTIMATED
BELOW DETECTION LIMIT
PCE CONCENTRATIONS
FROM CLP ANALYSES
PARKSIDE APARTMENTS
North "em Area 1
FIGURE 7
AR30U69
-------
SO
CO
CD
•e-
>*4
O
Table 3
ANALYSES OF ORGANIC COMPOUNDS IN GROUNDWATER SAMPLES
OBTAINED FROM RESIDENTIAL, INDUSTRIAL, AND MUNICIPAL WELLS
Well ID
Sample Number
R-l
OW1-OJ
R-l
OW1-02
(DUP)
R-2
GW6-01
R-4
OW2-01
R-7
GW8-01
R-8
OW7-01
Mennonhe
Home
R-10
OW9-01
Compound
l.U-TCAOig/l)
M-DCAfo/l)
Benzene fyig/l)
BDCM Otg/l)
Carbon disulflde &ig/l)
Chloroform (ng/l)
Chloromethane (ftgfl)
1,2-DCB (total)
0*8/1)
Elhylbenzcne fyig/1)
PCBO*g/>)
Toluene (fig/1)
trans-l^-DCB Oig/l)
TCBOig/l)
<1
<1
<1
<1
<1
<1
0.6 J
1
<1
<1
<1
<1
0.7 J
<1
<1
03 J
<1
1
<1
<1
0.7 J
Notes: DCA Dlchloroeihane
DCB Dlchtoroethene
TCA Trichloroethane
PCB fetrachloroelhene
TCB Trichloroelhene
BDCM Bromodichloromethane
DUP Duplicate (ample
I : J Indicate* that the sample contains the compound at an estimated concentration.
-------
SOUtXFfTON
TETRACHLOROEiree
U.VTCA
12-OCE (TOTAL)
ETHYLBEHZENE
TRANS-U-OCE
CARBON DISULFIOE
OtAROFOflM
XVVOCA
lETRACHjOROETHENE tf.V
CHLOROMETHAhC
E1HYLBENZSC OJJDe
TOCUBC Oil UVWAMFD
CARBON DISULFIOE 0.1
SSHJOROFORM
CHLOROMETHANE
ETHYISENZENE
TOLUENE
SOURCE: U. S. GEOLOGICAL SURVEY 7-1/2 MINUTE QUADRANGLE MAP FOR TELFORD. PA.
LEGEND
A
S-2
R-X
MPWA WELL
RESIDENTIAL WELL
BOROUGH AND TOWNSHIP
BOUNDARIES
NOTES;
1. DATA ARE IN pg/l
2. MULTIPLE RESULTS FOR ONE WELL AND
COMPOUND INDICATE DUPLICATE.
600 7200 7800
SCALf: 7-=7200'
RESULTS OF ANALYSES OF
GROUNDWATER FOR VOGS
North Pem Area 1
FIGURE 9
flR30U7l
-------
detected suggests that the Home well may not be contaminated by
the same plume as the other wells at the Site.
Other VOCs identified in ground water from the 13 wells
sampled were benzene (two detections), bromodichloromethane (two
detections), carbon disulfide (three detections), chloroform (two
detections), chloromethane (nine detections), ethylbenzene (eight
detections), and toluene (five detections). These VOCs were
distributed widely among the wells, without being limited to
either municipal wells only or residential wells only. It should
be noted that except for 2 M9/1 of chloromethane estimated in a
sample from well R-4, the concentrations of all of these VOCs are
less than or equal to 1 pg/l.
Residential wells R-17 and R-19 are both shallow dug wells
and do not therefore characterize the bedrock ground water
quality. However, because of their proximity to Gentle Cleaners,
both have probably been contaminated by the cleaners as a result
of migration of contaminants in the soil. (These wells are not
used for drinking water supplies, but were sampled to provide
information on the characteristics of the shallow ground water in
these areas.)
Long-term data on VOC contamination in ground water are
available from NPWA wells S-2, S-4, S-8, S-9, and S-10. These ^
data are provided in the RI. PCE levels in well S-2 have
remained around 0.5 to 0.6 Mg/1 for several years. PCE
concentrations in well S-4 have varied widely between about 2 and
about 5 M9/1 and showed a general decline during 1991. These
wells were not resampled during the RI.
Wells S-8, S-9, and S-10- were resampled during the RI. PCE
levels in well S-8 remained at about the detection limit of 0.5
Mg/1 for several years but in 1990 and 1991 rose to values on the
order of about 1 /*
-------
well when the entire well was sampled during the RI. The level
of TCE detected in a sample from the entire well was about that
detected during the straddle-packer tests.
Ground water samples were collected from discrete intervals
in the GKH well and in well S-9. The discrete samples were
obtained by the use of straddle packers. Packers are balloon-
like devices, two of which are placed in the well at selected
intervals and pressurized, isolating the space in between them.
Samples from this space are removed through tubes in the packers,
allowing the characterization of ground water in just that
interval of the well.
The results of the packer sampling indicate that the
contamination extends throughout the total depths of both wells,
but that there are variations in contaminant levels. The samples
collected from well S-9 exhibited contaminant levels ranging from
8 to 17 M9/1 of PCE. TCE also was detected in the samples from
well S-9 wells at levels up to 0.3 M9/1- The fact that the
concentration of PCE was as high as 8 to 17 M9/1 in each of the
five packed intervals suggests that the sample of the entire well
may not have been representative of the level of contamination in
the entire well. It is possible that the location of the pump
used to purge the well drew water from the vicinity of a fracture
or group of fractures that provided relatively clean water to the
well. The well was sampled with a bailer lowered to this same
interval. The original pump that was installed in the well was
probably Used for the sampling in 1986 and 1987. This pump was
removed from the well so that packer testing could be performed.
The pump used for the purging was set higher in the well, and the
sample was obtained from a higher interval. This difference in
sampling technique may account for the difference in the
concentrations detected.
A ground water sample obtained from the GKH well in 1986
reportedly contained 250 M9/1 of 1,1,1-TCA, 33.5 /*g/l of PCE,
12.2 M9/1 of TCE, and lower concentrations of other VOCs. The
sample obtained from the packed intervals of the well during the
RI contained almost no 1,1,1-TCA or TCE and variable levels of
PCE, the latter ranging from 330 M9/1 at the top interval to 16
/ig/1 in a lower interval. These data suggest that the overall
concentrations of VOCs in this well have declined over time.
The highest concentrations of most VOCs in the GKM well were
found in a sample collected from the uppermost interval. During
video logging of the well, water was observed to be running into
the well borehole from fractures located below the bottom of the
casing but above the water level in the well; the fractures were
located at a depth of about 22 feet below the ground surface.
The water observed to be entering the well from these fractures
is probably surface infiltration or shallow ground water that has
passed through contaminated soil at Gentle Cleaners or other
12
AR30IU73-
-------
facilities, migrated to the bedrock surface, and entered
fractures in the bedrock, finally traveling to the GKM well. The
topography in this area slopes from Gentle Cleaners down towards
the GKM property and beyond, and the ground water above Gentle
Cleaners has much lower levels of contamination. The high PCE
levels found at Gentle Cleaners could easily be gradually
dissolving in the shallow water migrating through this area.
Contamination entering the well from these fractures would
contaminate the entire well.
The sample of the entire GKM well was collected more than 24
hours into the 72-hour pumping test performed in the well. By
that time the well had been purged of at least three well
volumes._ Samples, also were collected periodically throughout the
test and analyzed with the field GC to determine trends in
contaminant levels.
In all cases there is a sharp initial decline in
concentration, followed by a gradual decline or a tendency to
stabilize in most cases. An exception is an increase in 1,1-DCE
late in the test. It should be noted that the PCE concentration
had declined to a value on the order of 6 /ig/1 by the end of the
test and had dropped from an initial level of around 30 M9/1 to ;
about 10 M9/1 within a few hours of the beginning of the test. -
This decline and general stabilization in PCE concentration
suggests that the sample obtained from the entire well is
representative of the quality of the ground water in the vicinity
of the well, and that the packer tests discussed above reflect
the affects of the contamination migrating into the well from the
properties immediately adjacent to the well.
The concentrations of VOC contaminants detected in the
ground water samples collected in this RI are so low that there
is no evidence that DNAPLs are currently affecting ground water
quality at the Site. The concentrations observed are only a very
small percentage of the solubility limits of the VOCs of concern.
During the periodic sampling of the ground water being discharged
from the GKM well, the concentration of PCE stabilized but at a
concentration of only about 6 ng/1, well below the solubility
limit of PCE. Therefore, the presence of DNAPLs was not
indicated by this sampling.
In summary, contamination by VOCs of the ground water at the
Site still exists but may have declined in concentration over
time. PCE was detected at or above the MCL of 5 M9/1 only in
well S-9. PCE was detected, in this investigation, at a lower
concentration in production well S-10 and not detected at all in
production well S-8. PCE was detected in NPWA sampling in 1991
at less than 1 M9/l« Contamination from the Area 1 plume may
have affected a residential well southwest of the Site. High
concentrations of VOC contaminants are still entering the ground
13
-------
water, at least at the location of the GKM well, although they
are diluted in the aquifer to much lower levels.
There is no definitive evidence for the presence of DNAPLs
in the ground water at the Site. Even a concentration of PCE at
330 /ig/1, detected in packer sampling at the GKM well, is only
0.2 percent of the solubility of PCE. The solubility of pure-
phase PCE in water is approximately 150,000 /ig/1- Levels at 1%
or higher of the solubility for PCE would be indicative of the
possible presence of DNAPLs in the ground water. No
contamination at this level (1,500 pg/1) were found. However, it
is known that a spill of PCE occurred at Gentle Cleaners that
probably introduced DNAPLs to the subsurface, and the presence of
DNAPLs would explain why PCE was detected throughout the entire
depths of the GKM well and well S-9, although at concentrations
that are only a small fraction of the solubility of PCE.
6. Summary of Site Risks
This section provides a summary of the analysis of potential
risks to human health and the environment from this contamination
in the absence of any remedial action. A risk assessment was
completed as part of the Remedial Investigation/Feasibility 1
Study. The results of the risk assessment were used to help :
determine whether remediation is necessary, to help provide ':
justification for performing remedial action, and to assist in
determining what exposure pathways need to be remediated. The
following presents a summary of the results of the assessment.
Selection of Contaminants of Concern
The risk from only VOCs was quantified because there were no
data on any other potential contaminants. The 14 contaminants
identified as primary contaminants of toxicological or
environmental concern and selected for baseline risk assessment
are listed in Table 4. The chemicals of concern were selected on
the basis of the following criteria:
• The frequency of detection in soil and water (if a
contaminant was detected in fewer than 5 percent of the
samples, it was dropped as a contaminant of potential
concern.)
• Estimated concentrations of certain compounds
The soil at the Site was separated into three distinct areas,
specifically: Gentle Cleaners, Parkside Apartments, and Granite
Knitting Mills. The ground water, however, was treated the same
for the entire Site.
14
4R30U75
-------
Table 4
CONTAMINANTS OF CONCERN
Acetone
Benzene
Bromodichloromethane
Carbon disulfide
Chloroform
Chloromethane
1,1-Dichloroethane
Cis/trans-l,2-Dichloroethene
Ethylbenzene
Methylene chloride
Tetrachloroethene
Toluene
1,1,1-Trichloroethane
Trichloroethene
AR30U76
-------
Toxieity Assessment.
In general, toxicity assessment has two steps. The first
step, hazard identification, is the process of determining what
adverse health effects, if any, could result from exposure to a
particular chemical. The second step, dose-response evaluation,
quantitatively examines the relationship between the level of
exposure and the incidence of adverse health effects in an
exposed population.
Exposure Assessment
On the basis of RI data, pathways were identified through
which human population may be exposed now or in future to the
contaminants of concern. These pathways were evaluated in the
baseline risk assessment under current and potential land-use
conditions. A number of potential human exposure pathways have
been identified at the Site. These include:
• Soil - Existing and potential future ingestion and
dermal absorption of contaminants from surface and
subsurface soil
• Ground Water - Potential future residential use with
ingestion, dermal absorption, and inhalation of
volatilized compounds
• Air - Existing and potential future inhalation of
volatiles from contaminated soil
Table 5 presents the exposure pathways addressed in the baseline
risk assessment, highlighting which pathways were assessed
quantitatively and which were assessed qualitatively. Subsurface
soil was included as a potential exposure pathway for future
residents because excavation of soil, such as for the
installation of home foundations, could occur. Such excavation
could bring subsurface soil to the surface, allowing direct
exposure to the contaminants that have been detected in
subsurface soil.
Quantification of Exposure
Exposure pathways for current and future use were evaluated
separately.
Current Use
Soil - Residents and workers can come into contact with soil
through incidental ingestion and or dermal exposure. Exposure to
subsurface soil can occur during construction (worker) and after
construction (workers and residents) if contaminated soils are
left on the surface. The risk to residents is expected to be
15
AR30U77
-------
higher from exposure to subsurface soils than the risk to
workers. Only the risk to the resident was calculated.
In reviewing the data on surface soil (0 to 2 feet) for
Granite Knitting Hills, Gentle Cleaners, and Parkside Apartments,
it was noted that the Granite Knitting Mills facility has asphalt
or buildings covering all available surface soil and, therefore,
no potential for direct contact with surface soil at the facility
exists. Therefore, the potential risks associated with current
direct contact with surface soil were discussed in a qualitative
rather than quantitative manner for the Granite Knitting Mills
facility.
Air - The air pathways represented by outdoor exposure to
VOCs in soil (workers and residents) or from VOCs in soil
entering the home (residents) were treated in a qualitative
manner because of the relatively low VOC concentration in surface
soil and the statement in Risk Assessment Guidance for Superfund
(RAGS) Part B (EPA, 1991), specifically: "for many undisturbed
Sites with vegetative cover such as those found in areas of
residential land use, air pathways are relatively minor
contributors of risk." The low levels of VOCs in surface soil
imply that this is not a viable source of either ingestion or
inhalation of VOCs outdoors. The potential might exist for
subsurface VOCs to migrate into homes along fractures in the soil
and through cracks in home foundations. Again, the relatively
low levels of VOCs in subsurface soil indicate that this is not a
potential pathway of great concern.
Ground Water - Residential use of contaminated ground water
for drinking water for current and future residents would lead to
exposure through direct ingestion of water and drinks made from
water; inhalation of vapors during showers, baths, and washing;
and dermal absorption during showers and baths. Only reasonable
maximum (or upper-bound) exposure assumptions were used for the
residential-use-of-ground water scenario because of the limited
range of the parameters needed to calculate intake. The upper
boundary of intake-factor values for the ingestion rate, exposure
frequency, exposure duration, body weight, and averaging time
were used to calculate reasonable maximum exposure. Unlike the
other exposure scenarios no average exposure scenario is
presented for ground water.
Future Use
Table 5 shows that for future land use, residents
potentially could be exposed to ground water on the Site and to
subsurface soils following excavation of soil.
Risk Characterization
Summary tables of risk characterization results are shown in
16
AR30U78
-------
TableS
EXPOSURE PATHWAYS ADDRESSED
Receptor
(Onsite)
Media
Exposure Route
Quantitative
Qualitative
Assessment
Current Land Use
Residents — Onsite
Residents— Offcite
Workers — Onsite
Surface Soil
Air (outdoors)
(indoors)
Groundwater
Surface Soil
Air (outdoors)
Ingestion
Dermal Absorption
Inhalation '
Inhalation
Ingestion
Dermal Absorption
Inhalation (Indoor
Volatile)
Ingestion
Dermal Absorption
Inhalation
X
X
X
X
X
X
X
X
X
Future Land Use
Residents — Onsite
Groundwater
Subsurface Soil
Ingestion
Dermal Absorption
Inhalation (Indoor
Volatile)
Ingestion
Dermal Absorption
X
X
X
X
X
AR3DU79
-------
Table 6 for residential ground water (current and future) and in
Table 7 for subsurface soil (future residents only). Included in
the tables are estimates of central tendency (or average)
exposure as well as reasonable maximum exposure.
Excess lifetime cancer risks are determined by multiplying
the intake level with the cancer potency factor. These risks are
probabilities that are generally expressed in scientific notation
(e.g., IxlO"6 or 1E-6). An excess lifetime cancer risk of lxlO~6
indicates that, as a plausible upper bound, an individual has a
one in one million chance of developing cancer as a result of
Site-related exposure to a carcinogen over a 70-year lifetime
under the specific exposure conditions at a Site.
Potential concern for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the hazard
quotient (HQ) (or the ratio of the estimated intake derived from
the contaminant concentration in a given medium to the
contaminant's reference dose). By adding the HQs for all
contaminants within a medium or across all media to which a given
population may reasonably be exposed, the Hazard Index (HI) can
be generated. The HI provides a useful reference point for
gauging the potential significance of multiple contaminant ;
exposures within a single medium or across media.
Results of Risk Assessment
Residential Ground Water Use - For ground water, the overall
result is that the relatively low concentrations of VOCs equate
to low risk levels. From the maximum concentrations detected,
none of the VOCs are above their MCLs; most are near their
detection limit. The excess lifetime cancer risk for current
offsite residential use for a child calculated using reasonable
maximum exposure assumptions and upper-bound concentrations is
about 1 x 10~6. For potential future onsite residential use, the
excess lifetime cancer risk for a child is 2 x 10~6, while for an
adult it is 3 x 10~6. Potential future onsite residential use
was also calculated for ground water infiltrating through the
soil and into the shallow aquifer. A grab sample showed a very
high concentration of PCE (330 M9/1)• This shallow ground water
scenario yielded an excess lifetime cancer risk of 2 x 10~4 for a
child and 3 x 10~4 for an adult, and a hazard index of 8 for a
child and 3 for an adult. These levels are above EPA's remedial
action levels for NPL sites.
Exposure to Contaminated Soil - For soil, the excess
lifetime cancer risks from direct contact or ingestion for both a
child and an adult at Parkside Apartments are well below EPA's
target risk level. The excess lifetime cancer risk from
ingestion and dermal contact with subsurface soil at Granite
Knitting Mills is at or near EPA's target level for an adult and
a child.
17
AR30U80
-------
The excess lifetime cancer risk for Gentle Cleaners is at
least 10 times higher than that of the other two facilities. PCE
(found at 300,000 Mg/kg at the 8- to 10-foot interval) is the
primary contaminant, leading to a reasonable maximum excess
lifetime cancer risk of 1 x 10~4 for both a child and an adult.
Due to the higher levels of contamination found on this property,
the soil there poses a greater threat to human health. However,
since these concentrations are 8 to 10 feet below the surface,
this is only a concern if the area is disturbed by excavation.
Although the soil contamination does not pose significant
risks in and of itself, the levels are high enough that continued
migration from soil to ground water could result in ground water
concentrations that pose a threat to anyone consuming this water.
Table 7 gives the summary of risk characterization results
for potential future contact by onsite residents with subsurface
soil following excavation. The assumptions used to predict risk
from this scenario are very conservative.
Conclusion of summary of Site Risks
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
presented in this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
7. Description of Alternatives
In accordance with section 300.430(e)(9) of the National Oil
and Hazardous Substances Contingency Plan (NCP), 40 C.F.R. §
300.430(e)(9), remedial response actions were identified and
screened for effectiveness, implementability, and cost during the
FS to meet remedial action objectives at the Site. The
technologies that passed the screening were developed into
remedial alternatives. EPA assessed these alternatives against
the nine criteria specified in the NCP at 40 C.F.R. Section
300.430(e)(9)(iii). In addition, EPA evaluated the No Action
Alternative (Alternative 1) as required by the National
Contingency Plan (NCP). These alternatives are presented and
discussed below, first for the soil contamination operable unit,
and then for the ground water operable unit. All projected costs
and implementation time frames provided for the alternatives
below are estimates. The time frames, except where noted, are
estimated times for meeting the remedial objectives, not just for
completion of construction activities.
Source Control Alternatives
The following alternatives were evaluated for the source
control operable unit (addressing the soil contamination at the
three properties). For estimates of the length of time for
18
AR30H8I
-------
CO
CD
CO
TO
Table 6
SUMMARY OF RISK CHARACTERIZATION RESULTS
RESIDENTIAL GROUNDWATER USE
Page 1 of 2
Scenario/
Location
Exposure
Pathway
Hazard Index
Average
Reasonable
Maximum
Excess Lifetime Cancer Risk
Average
Reasonable
Maximum
Current/Ofbite
Child
Adult
Ingestion '
Dermal
Inhalation
Total
Ingestion
Dermal
Inhalation
Total
0.01
0.01
0.03 '
0.05
0.01
0.003
0.007
0.02
Future/Onsite
Child
Ingestion
Dermal
Inhalation
Total
0.03
0.01
0.09
0.1
0.01
0.01
0.04
0.06
0.01
0.004
0.009
0.02
4 x lO'7
2 x lO'7
5 x 10'7
1x10-*
SxlO-7
5 x 10 7
4 x 10'7
2x10"
6 x ia7
3 x Id"7
5 x lO'7
IxlO4
1x10"
6xlO-7
5 x 10 7
2 x 10"
0.05
0.03
0.2
0.3
8 x lO'7
5 x lO'7
4xlO-7
2x10"
2x10"
IxlO4
5xl(T7
4x10"
-------
Table 6
SUMMARY OF RISK CHARACTERIZATION RESULTS
RESIDENTIAL GROUNDWATER USE
1 Page 2 of 2
Scenario/
Location
Adult
Exposure
Pathway
Ingestion
Dermal
Inhalation
Total
Hazard Index
Average
0.01
0.01
0.02
0.04
Reasonable
Maximum
0.02
0.01
0.03
0.06
Excess Lifetime Cancer Risk
Average
1x10*
1x10*
4 x la7
2x10*
Reasonable
Maximum
3x10*
2x10*
4 x 10-7
5x10*
Future/Onsite — Shallow Aquifer Scenario (Highest Concentration of PCE)
Child
Adult
Ingestion
Dermal
Inhalation
Total
Ingestion
Dermal
Inhalation
Total
2.1
1.4
4.9
8
0.9
0.8
1.0
3
9x10*
6x10*
8x10*
2x10*
2x10*
1x10*
7x10*
3x10*
CO
O
CO
CO
WDCR669/015.51
-------
CO
CD
•1=-
co
Table 7
SUMMARY OF RISK CHARACTERIZATION RESULTS
POTENTIAL FUTURE CONTACT WITH SUBSURFACE SOIL
Page 1 of 2
Location
Exposure
Pathway
Hazard Index
Average
Reasonable
Maximum
Excess Lifetime Cancer Risk
Average
Reasonable
Maximum
Parkside Apartments
Child
Adult
Ingestion '
Dermal
Total
Ingestion
Dermal
Total
<0.001
<0.001
<0.01 ;
<0.001
<0.001
<0.01
<0.001
0.001
<0.01
<0.001
<0.001
<0.01
2 x 10'
4 x 10-10
2 x 10'
3 x Iff10
2 x 10-10
5xiaw
6 x 10*
4x10*
5x10*
3x10*
3xlO»
3x10*
Granite Knitting Mills
Child
Adult
Ingestion
Dermal
Total
Ingertion
Dermal
Total
0.001
< 0.001
<0.01
< 0.001
< 0.001
<0.01
0.009
0.05
0.06
<0.001
0.01
0.01
5x10*
1x10*
6x10*
8x10-'
5 x la9
IxlOV
4 x lO'7
2x10*
2x10*
2 x 10 7
2x10^
2x10*
-------
Table 7
SUMMARY OF RISK CHARACTERIZATION RESULTS
POTENTIAL FUTURE CONTACT WITH SUBSURFACE SOIL
Page 2 of 2
Location
Exposure
Pathway
Hazard Index
Average
Reasonable
Maximum
Excess Lifetime Cancer Risk
Average
Reasonable
Maximum
Gentle Cleaners
Child
Adult
Ingestion
Dermal
Total
Ingestion
Dermal
Total
0.06
0.02
0.08 "
0.007
0.004
0.01
0.4
2.3
3
0.04
0.5
0.5
3x10*
7xlO-7
4x10*
5xlO-?
3 x 10-7
1x10*
2x10-'
ixur1
IxlO*
7x10-*
9xia5
Ixlfr*
CO
o
co
en
-------
cleanup and for the soil cleanup levels, the Summers model was
used, with protection of ground water to background levels (using
minimum detection limits) as the cleanup goal.
Alternative 1; No Actioq
Capital Cost: $o
O&M Costs: $o
Present Worth: $o
Time to Implement: o
Under the No Action alternative, no control or remediation
of contaminated soil would take place. EPA evaluates a "No
Action11 alternative for every remedial action in order to
establish a baseline for comparison of alternatives, as required
by the National Contingency Plan (NCP), 40 C.F.R. Part 300, which
regulates Superfund Actions.
The contamination levels in the soil would gradually decline
due to natural attenuation processes that break down the
contamination. These processes include biodegradation,
volatilization, adsorption, dispersion, and photolysis. It would
take between 8 and 25 years for these processes to reduce the
soil contamination to levels considered protective of human
health and the environment (not considering ground water
exposure). During this time, no monitoring or testing of the
soil contamination levels or conditions would occur.
Alternative 2: Natural Attenuation
Capital Cost: $0
O&H Costs: $13,704
Present Worth: $150,744
Time to Implement: 10 years
The Natural Attenuation alternative involves taking no
action to reduce the levels of contamination in the soil, but
allowing natural processes to reduce the contamination levels.
The processes involved include biodegradation, volatilization,
adsorption, dispersion, and photolysis. This alternative is
similar to Alternative 1, except that a regular monitoring
program would be initiated to keep track of the contamination
levels in the soil. Soil samples would be collected quarterly
until contamination levels in the soil have reached acceptable
levels. The cost estimates above are based on a 10 year period.
It is estimated that natural attenuation would take between 8 and
25 years to reduce soil contamination levels to the remediation
goals.
19
4R30U86
-------
Alternative 3 - Excavation and Offsite Disposal
Capital Cost: $429,516
O&M Costs: $0
Present Worth: $429,516
Time to Implement: i year
This alternative involves the excavation of soils at each of
the three properties with PCE contamination that exceeds the
remediation goals. This soil would be shipped to an approved
facility for disposal. The remediation goals were developed for
each property by evaluating the concentration of contaminants,
the depth to ground water, the subsurface conditions, and other
factors. The remediation goals and estimated quantity of soils
needing to be removed for each property are:
Remediation Goal Estimated Quantity
Property for PCE in Soils of Soils to be Removed
Gentle Cleaners 270 ppb 115 cubic yds.
Granite Knitting Mills 260 ppb 400 " "
Parkside Apartments 820 ppb 95 " n
Once the excavation starts, soil samples would be collected as
soil is removed from the areas of contamination, and the
excavation would be continued until the samples show that the
remaining soil meets the remediation goals listed above. The
contaminated soil would be placed in covered dump trucks or
dumpsters until proper transport and disposal could be arranged.
When all the contaminated soil is removed, clean fill will be
brought in, the areas will be returned to their original contours
and restored to previous conditions to the extent possible.
Ground Water Alternatives
The following interim action alternatives were considered
for the ground water operable unit at the Site.
Alternative i — No Action
Capital Cost: $0
O&M Costs: $0
Present Worth: $0
Time to Implement: 0
The no action alternative is required by the National
Contingency Plan, 40 C.F.R. Part 300, as a baseline alternative
against which other alternatives can be compared. Under this
alternative, no control or remediation of the ground water would
occur. The contamination levels in the ground water would
gradually decline due to natural attenuation processes that break
down the contamination. These processes include biodegradation,
volatilization, adsorption, dispersion/dilution, and hydrolysis.
20
HR30U87
-------
It would take approximately 91 years for these processes to
reduce the contamination to levels considered protective of human
health and the environment (or approximately 76 years if the soil
contamination is removed). During this time, no monitoring or
testing of the soil contamination levels or conditions would
occur.
Alternative 2 - Natural AttenuaiHnn
Capital Cost: $0
O&M Costs: $11,040
Present Worth: $367,620
Time to Implement: 30
This alternative relies on natural processes to
decontaminate ground water. These processes include
biodegradation, volatilization, adsorption, dispersion, and
photolysis. The only activity undertaken during natural
attenuation is quarterly monitoring of the contaminants of
concern in the subject area. The results of the monitoring would
be used to determine if natural attenuation was decreasing the
concentrations of the contaminants and providing sufficient
protection to human health and the environment. The monitoring :
would include obtaining ground water samples from the GKM well 1
and well S-9, and would continue until the 5-year review, at
which time a decision would be made by EPA whether or not
continued monitoring was necessary. (The costs noted above are
based on a 30-year monitoring period.)
If at any time during the monitoring period the ground water
concentrations at well S-9 begin to increase to the point where
they could affect the drinking water wells to the southwest, then
available remedies would be evaluated, and a decision made on the
appropriate remedial action to take. Natural attenuation is a
viable alternative because ground water concentrations of PCE
have decreased over time. However, it is estimated that it would
take at least 76 years for ground water levels to reach
protective levels through this method.
Alternative 3 - Extraction of Ground Water From GKM Well and Air
Stripping Treatment
Capital Cost: $7,586
O&M Costs: $13,593
Present Worth: $417,000
Time to Implement: 30 years
Alternative 3 includes pumping the entire GKM well, treating
the extracted water using an air stripper, and discharging the
treated water to the local sewer system or a nearby stream. Any
effluent discharged to a stream would have to meet applicable or
relevant and appropriate requirements for such a discharge. It
21
•AR30U88
-------
is estimated that 13 gallons per minute of contaminated water
would be pumped from this well.
Air stripping technology will be used to remove the PCE
contamination from the water. Using this treatment, air is blown
up through water as it trickles down through a tower or vessel.
The contact between the air and the water allows the PCE to
evaporate from the water into the air. The water is collected at
the bottom of the unit, while the air (containing very low levels
of contamination) is discharged at the top. The air emissions
will be tested initially to ensure that there is no health threat
posed by these emissions. The water is tested on a routine basis
to ensure that it meets any discharge limitations, and to ensure
the proper operation of the air stripping unit. An option to the
air stripper would be to discharge the pumped ground water
directly to the local sewer system, if it met discharge
requirements. For each of the extraction alternatives (3, 4, or
5), this option will be evaluated during the Remedial Design.
This option also includes the monitoring of wells S-9 and S-
10 to ensure that contamination is not spreading towards the
municipal drinking water wells. Additional monitoring wells
would be installed in locations determined to reveal the most •
information on the effectiveness of the pumping system. •
This alternative would withdraw water from near the
upgradient edge of the plume, and would prevent the contamination
from moving further downgradient towards wells S-9 and S-10.
Alternative 4 — Extraction of Ground Water from the Upper
Interval of the GKM Well and Air Stripping Treatment
Capital Cost: $7,586
O&M Costs: $12,417
Present Worth: $381,000
Time to Implement: 30 years
This alternative includes pumping the upper (most
contaminated) part of the GKM well. The extracted ground water
would be treated in an air stripper. The total flow rate from
the upper interval of the GKM well is estimated to be less than 1
gallon per minute (gpm), so an intermittent pumping operation
would be required. This alternative would be effective in
reducing contaminant concentrations in the ground water, since
this upper interval was found to contain the highest level of
contamination identified during the Remedial Investigation. The
same monitoring program as discussed in Alternative 3 would be
initiated under this Alternative.
22
4R30U89
-------
Alternative 5 - Extraction of Ground Water from Well S-9 with Air
Stripping Treatment
Capital Cost: $8,586
O&M Costs: $22,829
Present Worth: $695,000
Tine to Implement: 30 years
This alternative involves pumping of the entire volume of
well S-9, and treating of the extracted ground water in an air
stripper. This well would be expected to produce about 80 gpm of
contaminated water. This well is located in the approximate
center of. the plume, and therefore would be effective in
containing the plume and preventing migration of contamination to
wells that have not yet been impacted. Contamination levels in
different intervals in this well have ranged from 9 to 24 parts
per billion. By pumping this well, pockets of contamination that
exist between the Gentle Cleaners and Granite Knitting Mills
properties may be drawn into the well and pumped out. This well
is also deeper than the Granite Knitting Mills well, and will
withdraw water from the deeper interval (which has some
contamination in it) . The same monitoring program as discussed ;
in Alternative 3 would be initiated under this Alternative.
8. suTnitiayy of comparative Analsis of Alternatives
The Alternatives discussed above were compared on the basis
of the nine criteria set forth in the NCP at 40 C.F.R. Section
300.430(e)(9) in order to select a remedy for the ground water
Operable Unit. These nine criteria are categorized according to
the three groups below:
THRESHOLD CER
Overall protection of human health and the environment
Compliance with applicable or relevant and appropriate
requirements (ARARs)
PRIMARY KAT.AMCING CRITERIA
Long-term effectiveness and permanence
Reduction of toxicity, mobility, or volume through treatment
Short-term effectiveness
Imp lementabi 1 ity
Cost
MODIFYING CRITERIA
Community acceptance
State acceptance
23
flR30ll*90
-------
These evaluation criteria relate directly to the
requirements in Section 121 of CERCLA, 42 U.S.C. S 9621, which
determine the overall feasibility and acceptability of the
remedy.
Threshold criteria must be satisfied in order for a remedy
to be eligible for selection. Primary balancing criteria are
used to weigh major trade-offs among remedies. State and
community acceptance are modifying criteria formally taken into
account after public comment is received on the Proposed Plan. A
summary of each of the criteria is presented below, followed by a
summary of the relative performance of the soil and ground water
alternatives with respect to each of the nine criteria. These
summaries provide the basis for determining which alternative
provides the "best balance" of trade-offs with respect to the
nine criteria.
Overall Protection of Human Health and the Environment
CERCLA requires that the selected remedial action be
protective of human health and the environment. A remedy is
protective if it reduces current and potential risks to
acceptable levels within the established risk range posed by each
exposure pathway to the contamination. . _ . :
Compliance With ARARs
This criterion addresses whether a remedy will meet ARARs or
provide grounds for invoking a waiver under the-NCP at 40 C.F.R.
Section 300.430(f)(1)(ii)(C) and CERCLA, Section 12l(d)(4), 42
U.S.C. S 9621(d)(4). Under Section 121(d) of CERCLA, remedial
actions at CERCLA Sites must attain applicable or relevant and
appropriate standards, requirements, criteria, and limitations
(collectively referred to as "ARARs11) under federal environmental
laws and promulgated State environmental or facility siting laws,
unless such ARARs are waived pursuant to Section 121(d)(4) of
CERCLA.
Applicable requirements are those substantive environmental
standards, requirements, criteria, or limitations promulgated
under Federal or State law that are legally applicable to the
remedial action to be completed at the Site. A "legally
applicable" requirement is one which would legally apply to the
response action if that action were not taken pursuant to
Sections 104, 106, or 122 of CERCLA. Relevant and appropriate
requirements are those substantive environmental protection
standards, requirements, criteria, or limitations promulgated
under Federal or State law which, while not being legally
applicable to the remedial action, do pertain to problems or
situations sufficiently similar to those encountered at the Site
that their use is well suited to the Site. ARARs may relate to
the substances addressed by the remedial action, to the location
24
AR3GU9I
-------
of the Site, or to the manner in which the remedial action is
implemented.
CERCLA requires that remedial actions meet applicable or
relevant and appropriate requirements (ARARs) of other Federal
and state environmental laws or provide grounds for invoking a
waiver. These laws may include, but are not limited to, the
Toxic Substances Control Act, the Clean Water Act, the Safe
Drinking Water Act, and the Resource Conservation and Recovery
Act.
In addition, Section 121(d)(2) (A) of CERCLA requires a level
of cleanup "which at least attains Maximum Contaminant Level
Goals (MCLG) established under the Safe Drinking Water Act (42
U.S.C.A. S 300f et seq.) and water quality criteria (WQC)
established under section 304 or 303 of the Clean Water Act (33
U.S.C.A. § 1314 or 1313), where such goals or criteria are
relevant and appropriate under the circumstances of the release
. . . ." 42 U.S.C. S I21(d)(2)(A). In accordance with the NCP,
relevance and appropriateness of a requirement is determined by
comparing, where pertinent, the circumstances of a release to
eight factors discussed below. Pertinence of a factor depends,
in part, on whether a requirement addresses a chemical, location,
or action [40 C.F.R. S 300.400(g)(2)].
Long Term Effectiveness/Permanence
This evaluation criterion addresses the long-term protection
of human health and the environment after remedial action cleanup
goals have been achieved, and focuses on residual risks that will
remain after completion of the remedial action.
Reduction of Contaminant Toxicity. Mobility, and Volume Through
Treatment
This evaluation criterion addresses the degree to which a
technology or remedial alternative reduces the toxicity,
mobility, or volume of a hazardous substance. Section 121(b) of
CERCLA, 42 U.S.C. S 9621(b), establishes a preference for
remedial actions that permanently and significantly reduce the
toxicity, mobility, or volume of hazardous substances. A
combination of treatment and engineering controls may be used, as
appropriate, to achieve protection of human health and the
environment, as set forth in the NCP at 40 C.F.R. Section
300.430(a)(iii). Treatment should be utilized to address the
principal threats (such as liquids, high concentrations of toxic
compounds, and highly mobile materials) presented by a Site and
engineering controls such as containment will be considered for
wastes that pose a relatively' low, long term threat or where
treatment is impracticable. See 40 C.F.R. S 300.430(a)
25
-------
Short-term Effectiveness
This evaluation criterion addresses the period of time
needed to achieve protection of human health and the environment,
and any adverse impacts that may be posed by construction and
implementation of a remedy.
Imp 1 ement abi 1 i tv
This evaluation criterion addresses the technical and
administrative feasibility of each remedy, including the
availability of materials and services needed to implement the
chosen remedy.
Cost
The cost of each of the alternatives is evaluated, and
compared to the no action alternative.
State Acceptance
The EPA, as lead agency for this Site, selects the remedy in
consultation with the State. EPA has provided the information on
which this Record of Decision is based to the Pennsylvania
Department of Environmental Resources (PADER), and has had
discussions on this matter with PADER representatives. PADER has
not yet indicated whether or not it will concur with the final
action for OU1 and the interim action for OU2.
Community Acceptance
The comments and concerns expressed by the public during the
public meeting and during the comment period are considered.
This criterion includes a determination of which components of
the alternatives interested persons in the community support,
have reservations about, or oppose based on public comments.
SOURCE CONTROL ALTERNATIVES
Overall Protection of, Human Health and the Environment
Alternatives 1 and 2 would not protect human health or the
environment from present contamination levels. The risk posed by
the facilities would not be decreased to protective levels. The
risk of potential exposure to the contaminated media would
continue. These alternatives would only provide sufficient
protection of human health and environment when all soil PCE
concentrations were decreased through natural process. The
contaminated soil may require up to 16 years of natural
attenuation to reach the soil remediation goals for PCE in soil.
During this time, the monitoring done under Alternative 2 would
26
AR30U93
-------
provide information on the reduction in PCE levels occurring in
the soil, which would not be known under Alternative 1.
Alternative 3 would provide protection of human health by
eliminating the possible exposure to contaminated soil. All soil
with PCE at concentrations above the soil remediation goals would
be removed'from the Site and properly treated and/or disposed of
in an EPA-approyed disposal facility. This would also improve
the ground water by eliminating the primary source of
contamination.
Alternative 1 would not provide adequate protection of human
health and the environment and would not address the remedial
action objectives. Alternative 2 would require a long cleanup
time, and continual monitoring also would be required to verify
the effectiveness of natural attenuation. Alternative 3
(excavation and offsite disposal) would provide, short- and long-
term protection of human health and environment at the Site by
removing the contaminated soil.
Compliance with ARARa
The evaluation of the ability of the alternatives to comply
with ARARs included a review of chemical-specific and action-
specific ARARs that were presented in the Feasibility Study. --:
There are no known location-specific ARARs for the Site.
The no-action alternative would not meet any chemical-
specific A?ARs. Action-specific ARARs are not applicable because
no action would occur. Alternative 2 would eventually achieve
the remediation goal for PCE in soil. Action-specific ARARs are
not applicable because the only activity taken during natural
attenuation is quarterly monitoring of the contaminants of
concern. Alternative 3 would meet the remediation goal for PCE
at each facility, and would meet ARARs for such actions.
Loner-Term Effectiveness and Permanence
The no-action alternative would not provide long-term
effectiveness and permanence. The risk currently associated with
the facilities would not be decreased and may be increased
through continued migration of contaminants. Although natural
attenuation processes could occur, this alternative provides ho
control or monitoring of the contaminants. Because contaminants
would be left at the facilities, a review of the Site conditions
would be required every 5 years. Alternative 2 would eliminate
long-term exposure to contaminants because natural processes
would reduce contaminant concentrations, and the monitoring would
provide information on the current levels of contamination and on
when the remediation goals were reached. Alternatives -1 and 2
would also not contribute to improvements in ground water.
Alternative 3 would eliminate short- and long-term exposure to
27
-------
PCE in concentrations greater than remediation goals because
contaminated soil above these goals would be removed from the
Site. The long-term effectiveness would be realized by properly
treating the contaminated soil before landfilling.
Alternative 3 would provide a higher degree of long-term
protection from risks than would alternatives l and 2.
Reduction of Toxicity. Mobility, and Volume Through Treatment
Alternatives 1 and 2 would not provide any reduction of
toxicity, mobility, and volume and would not meet the statutory
preference for treatment. For Alternative 2 the monitoring
results would be used to verify that natural attenuation was
decreasing the concentrations of the contaminants. Alternative 3
would reduce the mobility and migration of contaminants because
the contaminants would be disposed of in a permitted landfill
offsite. Alternatives 2 and 3 would provide reduction-fn
toxicity, mobility, and volume of the contaminated soil.'=
Short-Term Effectiveness
Because no action would occur under Alternative 1, the level
of risk to human health and the environment would remain at
current levels. Under alternative 2, the level of short-term
risk to human health and the environment would remain at current
levels. Alternative 1 and 2 would not affect human health during
their implementation. Implementation of alternative 3 would have
some potentially adverse effects on human health and the
environment. Volatile emissions and fugitive dust could increase
during the excavation and transportation of soil around the Site.
In addition, trucks would be required to transport the
contaminated soil to an offsite facility. The probability of
traffic accidents on the roads between the Site and the disposal
facility would increase. These impacts can be minimized by using
proper construction and transportation techniques.
There are no additional short-term risks associated with
alternatives 1 and 2. For alternative 3, short-term
effectiveness would be affected by the required excavation and
transportation of soil.
Implementabi1itv
The no-action alternative does not have a monitoring or
construction component associated with it; therefore, there are
no issues concerning implementation. Alternative 2 would be easy
to implement. Continual monitoring of the contaminants of
concern in the subject area would be required to verify the
effectiveness of natural attenuation. A contingency plan would
be developed for implementation if sampling data indicated that
the contamination was posing a threat to human or environmental.
28
AR30|tf95
-------
receptors. Alternative 3 is implementable. Its elements are all
routine construction activities. All equipment and materials
exist and are readily available. Soil may require treatment at a
disposal facility to comply with regulations.
Cost .
The table below summarizes the costs of the three soil
alternatives for the source control operable unit.
SUMMARY 07 COSTS OF SOIL ALTERNATIVES 1, 2, AND 3
-
Capital
Costs
O&M Costs
Total
Present
Worth Costs
Alternative
1
(No Action)
$0
$0
$0
Alternative
2 '
(Natural
Attenua-
tion)
$0
$13,704
$150,744
Alternative 3
(Excavation and Off site
Disposal of Soil
$429,516
$0
$429,516
The ho action alternative would require no expenditure of
money for. capital purposes. As part of the 5-year review
process, samples may be required and time expended on preparing a
report detailing the risk associated with the facilities.
However, these costs have not been included here. The capital
cost for Alternative 2 would be $0. The annual O&M cost would be
$13,704. The total present worth cost based on monitoring
conducted over a 10-year period would be $150,744. The total
present worth cost of alternative 3 is estimated to be $429,516.
No O&M costs are expected because the technology does not involve
an extended ^remediation period and because no long-term
management, "maintenance, or monitoring would be required.
State Acceptance
PADER has not indicated whether or not it concurs with the
final action remedy for OU1 and the interim action remedy for
OU2 .
Acceptance
This criterion includes a determination of which components
of the alternatives interested persons in the community support,
have reservations about, or oppose based on public comments. A
public meeting was held on the proposed plan on July 14, 1994 in
29
4R30U96
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July 6 through August 4f 1994. Comments received at the meeting
and during the comment period are discussed in the Responsiveness
Summary attached to this Record of Decision.
QROUHD WATER REMEDIATION ALTERNATIVES
Overall Protection Of Human Health and the Environment
The no-action alternative would not protect human health or
the environment from present contamination levels. The risk
posed by the facilities would not be decreased to protective
levels. The risk of potential exposure would continue from the
contaminated media. Alternative 2 would provide sufficient
protection to human health and environment when all ground water
PCE concentrations are decreased. It may take up to 91 years for
the process of natural attenuation to reduce, the contamination in
ground water to the background concentration if the contaminated
soil is not treated or removed from the Site. Up to 76 years
would be required if the contaminated soil is removed* During
this time, sampling would indicate the concentration levels and
location of contamination, and appropriate steps could be taken
if a health or environmental hazard is identified.
Alternative 3 would provide protection to both human health
and environment. Ground water extraction and air stripping -
treatment would reduce the threat to human health posed by
ingestion of contaminated ground water and would reduce the
possibility of further environmental degradation. This
alternative-is not totally effective in treating the entire plume
because the GKM well is at the head of the contaminant plume, and
would only withdraw a portion of the plume while pumping the
well. Also, large volumes of clean ground water would be pumped
from upgradient and sidegradient of the well because of the
well's location at the edge of the contaminant plume. Relying
solely on pumping, the GKM well appears to not be effective in
addressing the entire plume; however, the value in pumping from
this well is to intercept and remove the more highly contaminated
ground waters assumed to be present in and entering the aquifer in
the vicinity of Gentle Cleaners. Contaminated ground water
downgradient from the pumping influence of the GKM well would
continue to migrate toward pumping well S-10.
For Alternative 4, overall protection of both human health
and the environment would be similar to that of alternative 3.
The remediation time is estimated to be less than the cleanup
time for alternative 2 because the highly contaminated ground
water carrying through the fractures above the water level into
the well would be intercepted and pumped off. For Alternative 5,
overall protection of both human health and the environment would
be similar to that of alternative 3. The length of time required
for cleanup would vary depending on removal of the contaminated
soil (the source of contamination).
30
AR30U97
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Compliance with
The no-action alternative would not meet any chemical-
specific ARARs. Action-specific ARARs are not applicable because
no action occurs. Alternative 2 would achieve the MCL for PCE
once the natural attenuation processes are completed. Action-
specific ARARs are not applicable because the only activity taken
during natural attenuation is quarterly monitoring of the
contaminants of concern. Alternative 3 would meet the MCL for
PCE (5 Mg/1) • To meet action-specific ARARs, the ground water
treatment system would be designed to meet the NPDES criteria or
pretreatment standards for discharge of treated water to a POTW
or local surface water body. The air treatment systems for this
technology, if required, would be designed to comply with federal
and state regulations.
Alternative 4 and 5 would be similar to alternative 3 with
regard to ARARs. In addition, the ground water treatment system
for any treatment alternative would be designed to meet federal
and state limitations to prevent exceedances of the water quality
standards for discharge of treated water to the creek or
treatment plant.
Lona-Term Effectiveness and Permanence
Alternatives 1 and 2 would not provide long-term
effectiveness and permanence. The risk currently associated with
the facilities would not be decreased and may be increased
through migration of contaminants. This alternative would
provide no control of the contaminants. Because contaminants
would be left at the facility, a review of the Site conditions
would be required every 5 years. Alternative 2 would provide
information on the location and concentrations of contamination,
and indicate when the remediation goals have been met.
Alternative 3 would eliminate long-term exposure to contaminants
because human health risks posed by ingestion of ground water in
the future would be reduced commensurate with the reduction of
PCE to less -than 5 Mg/1 by the pump and treat systems.
The long-term effectiveness and permanence of alternatives 4 and
5 individually would be similar to that of alternative 3, except
that Alternative 5 would not prevent the migration of
contaminated ground water from the GKM well into the drinking.
water aquifer. The central location of Well S-9 in the plume
makes it a good choice for pumping for containment of the plume.
Reduction of Contaminant Toxicity. Mobility, and Vplvfflig Through
Treatment
Alternatives 1 and 2 would not provide any reduction of
toxicity, mobility, or volume beyond that from naturally
occurring processes, and would not meet the statutory preference
for treatment. For Alternative 2, the monitoring results would
31
AR30U98
-------
be used to verify that natural attenuation was decreasing the,
concentrations of the contaminants.
Under Alternative 3, pumping the GKM well withdraw the
contamination from the upgradient portion of the plume, which
would be effective in controlling the migration of contaminants
towards the municipal drinking water wells. Well s-9 is in the
radius of influence of the GKM well. Therefore, the ground water
that has contaminant concentrations near the MCL would be pulled
back to the northeast by the pumping of the GKM well.
Alternative 4 would reduce the toxicity of the water in the
aquifer by eliminating the highest source of contamination
entering, the aquifer (the shallow interval of the Granite
Knitting Mills well). This should help to limit the further
migration of the plume. This alternative would not address the
contamination that exists in the plume and that has moved into
lower levels of the aquifer. The water extracted from the upper
interval would be treated to levels safe for discharge.
Alternative 5, pumping of Well S-9, would reduce the levels
of contamination throughout the plume area. This well is located
in the approximate center of the plume; pumping of this well \
would withdraw contaminated water from throughout the plume. It-
would not eliminate the highest source of contamination entering
the aquifer, but would intercept this contamination as it moved
down into the aquifer and downgradient of the GKM well. The
water extracted from the this well would be treated to levels
safe for'discharge.
Short-Term Effectiveness
Because no action would occur under Alternative 1, the level
of risk to human health and the environment remains at current
levels. No short term benefits or risks would be realized.
Under alternative 2, the level of short-term risk to human health
and the environment would remain at current levels. On the other
hand, alternative 2 would not affect human health during
'implementation, and would provide information on the degree and
location of contamination. . • •
For Alternative 3, the air stripper would produce the off-
gas at a very low emission rate of 1.95 x 10~5 Ib/hr of PCE,
which is considered insignificant. Once the ground water
extraction and treatment systems are installed, the contaminant
plume would begin to recede from its current position.
Implementation of alternative 4 would have some possibility of
risk, similar to that of alternative 3. The emission rate is
estimated at 1.5 x 10~6 Ib/hr of PCE. Alternative 5 would have
some possibility of risk, similar to that of alternative 3. The
emission rate is estimated at 2.0 x 10~4 Ib/hr of PCE. Each of
these alternatives also involves some minor construction
32
AR30U99-
-------
activities and vehicular traffic. It is possible that monitoring
wells may need to be installed to assist in the performance
evaluation of the pump and treat system(s).
I^nplementabllity
Alternative l does not have a monitoring or construction
component associated with it; therefore, there are no issues
concerning implementation. Alternative 2 would be easy to
implement. Periodic monitoring of the contaminants of concern in
the subject area would be required to verify the effectiveness of
natural attenuation. A contingency plan (extraction/treatment)
would be developed for implementation if the sampling data
indicated that contamination was posing a threat to human or
environmental receptors.
Alternative 3 is implementable. It involves the use of
proven technologies. All equipment and materials exist and are
readily available. Operation would require monitoring of the
ground water and the air to assess the effectiveness of the
ground water extraction and treatment systems. One potential
disadvantage of Alternative 3 is that much of the extracted
ground water could have a PCE concentration near or below 5 pg/1.
Pumping test data indicate that, after 24 hours of pumping, the
PCE concentration in the extracted ground water decreased over i
time and the sample sent to the CLP had a concentration of 3
Mg/1. Alternative 3 could therefore be needlessly treating water
that already meets the MCL.
.->--
The implementation of alternative 4 would be the same as
that of alternative 3, except only periodic pumping of the upper
part of the well is feasible because it will generate only 1 gpm.
Alternative 4 has an advantage in that only a small amount of
contaminated ground water from the GKM well would need to be
removed and treated. The disadvantage is that only periodic
pumping of the upper part of the well is feasible, which makes
treatment operations difficult.
The implementation of Alternative 5 would be the same as
that of alternative 3, except that only the contaminated ground
water from well S-9, and not from the GKM well, would be
extracted and treated. Alternative 5 has a disadvantage in that
well S-9 will produce a large volume (80 gpm) of relatively clean
ground water that, would need to be treated before discharge to a
sewer or nearby stream (unless direct discharge to a treatment
plan can be arranged).
Cost
Taking no action would require no expenditure of money for
capital purposes. The capital cost for Alternative 2 would be
$0. The O&M costs would be $11,140 per year. The total present
33
flR30!500
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worth cost based on monitoring over a 30-year period would be
$367,620.
The estimated present worth cost of alternative 3 would be
$417,000, with a capital cost of $7,586 and an annual O&M cost of
$13,593. The total present worth cost for Alternative 4 is
estimated to be $381,000 based on a capital cost of $7,586 and an
annual O&M cost of $12,417. The total present worth cost for
Alternative 5 is estimated to be $695,000. The capital cost is
$8,586, and the annual O&M cost is $22,829. Each of these
estimates is based on a thirty year operating period.
The table below summarizes the costs of the five ground
water alternatives.
I) SUMMARY OF COSTS OF GROUND WATER ALTERNATIVES 1 THROUGH 5 9
Capital
Costs
O&M Costa
(per year)
Total
Present
Worth
Costs
Alt. 1
(Ho Action)
$0
$0
$0
Alt. 2
(Natural
Attenua-
tion)
so
$11,040
$367,620
Alt. 3
(Extract-
ion from
GKM Well
and Treat-
aent)
$7,586
$13,593
$417,000
Alt. 4
(Extract-
ion fro*
Upper Part
of GKM Well
^n4
Treatment )
$7,586
$12,417
$381,000
Alt. 5
Extract-
ion From
Well
8-9 and
Treat-
aent)
$8,586
$22,829
$695,000
State Acceptance
FADER has not indicated whether or not it concurs with the
final actioniremedy for OU1 and the interim action remedy for
OU2. .
Y
Community Acceptance
As discussed in the "Community Acceptance" section under the
soil remediation alternatives evaluation, the comments and
concerns expressed by the community are presented in the
Responsiveness Summary attached to the Record of Decision.
9. Selected Remedy and Performance Standards
Based on the comparisons of the nine evaluation factors for
each of the alternatives, Alternative 3 for source control
34
4R30I50!
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operable unit (Excavation and Offsite Disposal of contaminated
soil) and a combination of Alternatives 4 and 5 for the ground
water operable unit (Pumping and Treating of the upper interval
of the Granite Knitting Mills well and the entire Well S-9), are
the selected remedies for the Site. The Proposed Plan for the
North Penn Area 1 site was released on July 5, 1994. The
Proposed Plan identified the alternatives listed above as the
preferred alternatives. EPA reviewed all written and verbal
comments submitted during the public comment period. Upon review
of these comments, it was determined that no significant changes
to the remedies, as originally identified in the Proposed Plan,
were necessary.
Source Control Operable Unit
Alternative 3 for the remediation of contaminated soil will
involve the excavation of soils at each of the three properties
with PCE contamination that exceeds the remediation goals. This
soil would be shipped to an approved facility for disposal. The
remediation goals were developed for each property by evaluating
the concentration of contaminants, the depth to ground water, the
subsurface conditions, and other factors. The performance
standards for remediating the soils, and the estimated quantity;
of soils needing to be removed for each property, are presented •
below. These were developed through the use of the Summers i
model, with protection of ground water to background levels
(using minimum detection limits) as the cleanup goal.
'.-»- Remediation Goal Estimated Quantity
Property for PCE in Soils of Soils to be Removed
Gentle Cleaners 270 ppb 115 cubic yds.
Granite Knitting Mills 260 ppb 400 cubic yds.
Parkside Apartments 820 ppb 95 cubic yds.
Once the excavation starts, soil samples would be collected as
soil is removed from the areas of contamination, and the
excavation would be continued until the remaining soil meets the
remediation 'goals listed above. The contaminated soil would be
placed in covered dump trucks or dumpsters until proper transport
and disposal can be arranged. The contaminated soil will be
disposed of at an EPA-approved facility that is permitted to
accept such wastes. When all the contaminated soil is removed,
clean fill will be brought in, the areas will be returned to
their original contours and restored to previous conditions to
the extent possible. The generation, storage, and transport of
the contaminated soil will comply with the applicable and
relevant and appropriate requirements of Pennsylvania Waste
Management regulations at 25 Pa. Code Sections 262.12, .13, .20,
.30, and .34.
During the excavation process, appropriate measures will be
taken to minimize exposure of workers and nearby residents to
35
3R30 15.02
-------
contamination. Air monitoring will be conducted by EPA and/or
its contractors, and levels will be established which, if
exceeded, will require the implementation of additional control
measures or the cessation of all work activities. Barriers or
fences will be installed to limit access to the excavation and
staging areas.
Implementation of Alternative 3 for the source control
operable unit will remove any threat of direct contact exposure.
In addition, a goal of this action, in conjunction with the
remedial action taken under OU2, is to remediate ground water to
levels established in the ARARs.
The actions taken under this remedial action will comply
with the applicable and relevant and appropriate sections of
Pennsylvania regulations, found at 25 Pa. Code Chapters 260-270,
Hazardous Waste. This Alternative will also comply with the
substantive requirements of Pennsylvania Erosion Control
Regulations, codified at 25 Pa. Code Chapter 102.
On-Site activities of the selected alternative will also be
performed in compliance with all other applicable legal
requirements (e.g., worker health and safety laws and 5
regulations, see 40 C.F.R. S 300.150) that are not within the ~
scope of federal environmental or state environmental or facility
siting laws.
Ground Water Operable Unit
~-~zy —
The selected interim action alternative for the ground water
operable unit is a combination of Alternatives 4 and 5.
Alternative 4 consists of pumping just the upper interval (the
top 30 to 40 feet) of the Granite Knitting Mills well. It is in
this interval that the highest levels of PCE are found entering
the well, and subsequently moving down into the drinking water
aquifer. By pumping this interval only, the high levels of PCE
are removed, while minimizing the amount of relatively clean
water that- would have to be treated. This well is located near
the upgradient end of the plume. The water in the deeper
intervals of this well (the well depth is approximately 190 feet)
is being drawn in from areas outside the plume, and therefore
pumping these intervals does not help eliminate the contamination
in the ground water. Pumping the shallow interval would yield
approximately 2 gallons per minute of water. This interval would
be packed off from the rest of the well, and pumped
intermittently when a sufficient quantity of water has built up
in the well.
Alternative 5 involves pumping of the entire'Well S-9. Due
to the central location of this well, pumping it is expected to
contain the plume and draw contaminated water from throughout the
plume area. This well is approximately 245 feet deep, and would
36
5R30I503
-------
produce approximately 80 gallons per minute of water. The
combination of pumping these two wells will eliminate the highest
source of contamination entering the ground water, and will also
contain the plume and remove some or all of the contamination
already in the ground water.
The water that is extracted from these wells will most
likely be combined and treated in one treatment system.The
treated water will be discharged to a local stream, or to the
local sewer system. One option that may be pursued is the direct
discharge of the extracted water to the sewage treatment plant.
The majority of the water extracted from the ground has
relatively low levels of contamination. This water (from Well S-
9) has PCE levels that typically are just above the Maximum
Contaminant Level (MCL) which is the level considered safe for
drinking water supplies. Although it may exceed the MCL,
contamination at this level does not present a threat to public
health or the environment if discharged to a sewage treatment
plant. Sewage treatment plants can generally handle water with
contamination levels in this range without adverse effects, and
can still meet discharge limitations that apply to them. The
smaller quantity of more highly contaminated water extracted from
the Granite Knitting Mills well will not significantly increase -
overall contamination levels when the flows are combined. ;
The exact design of the extraction and treatment system has
not yet been determined. During the design process, these
details will be worked out and approved by EPA and FADER. Prior
to selecting any particular option, proper approvals will have to
be obtained (e.g., approval from the local authorities for
discharge to the sewage treatment plant), and plans for the
remedial action will be presented to the public prior to its
implementation.
Ground Water Cleanup Levels
The well system for extracting ground water shall be
operated uncil the ground water is cleaned up to background
levels. The Pennsylvania ARAR for ground water for hazardous
substances is that all ground water must be remediated to
"background" quality as specified by 25 Pa.Code SS 264.90 -
264.100, specifically 25 Pa.Code SS 264.97(i) and (j) and S
264.100(a)(9), which are relevant and appropriate requirements
under the Pennsylvania Hazardous Waste Management Regulation.
The Commonwealth of Pennsylvania .also maintains that the
requirement to remediate to background is also found in other
legal authorities. The cleanup level for each contaminant of
concern in the ground water is the background concentration of
that contaminant. The background concentration for each
contaminant of concern shall be established by EPA during
Remedial Design. Pennsylvania's "Groundwater Protection
Strategy1*, dated February 1992, is a "to be considered"
37
AR30I50U
-------
requirement for determining appropriate ground water cleanup
levels. This strategy will be considered in the design of the
extraction system, and in the final remedial action taken for
this operable unit, in the event that a contaminant of concern -
is not detected in samples taken for the establishment of
background concentrations, the method detection limits of EPA
approved low level drinking water analytical methods with respect
to that contaminant of concern or MCLs, whichever are more
stringent, shall constitute the "background" concentration of the
contaminant.
Ground water Extraction system
The-ground water shall be decontaminated through extraction
and treatment of the contaminated ground water throughout the
area adjacent to the two pumped wells. The goal of the
extraction is to create a capture zone to capture contaminated
ground water throughout the plume. Ground water shall be
extracted using two extraction wells, the GKH well and Well S-9.
For the final remedial action for this operable unit, this
interim system shall be evaluated, and a determination will be
made on whether additional extraction wells are needed to '•?
remediate the plume. .!-
Air Stripper
The water from the extraction wells shall be treated using a
packed column air stripper. Air flow rates and air stripper
dimensions shall be determined during the remedial design and
shall be approved by EPA in consultation with PADER. Air
emissions from this unit will meet applicable or relevant and
appropriate Pennsylvania regulations at 25 Pa. Code, Chapters
123.1, 123.2, 123.31, and 123.41, and Chapter 127.1. Any wastes
generated at the stripper are subject to Waste Management
Regulations at 25 Pa. Code Chapters 260 and 261. As discussed
above, direct discharge to a sewage treatment plant may be
selected as-an alternative if proper approval can be obtained.
This would be done in consultation with the PADER and local
authorities.
Discharge of Treated Water
The treated water from the air stripper unit shall be
discharged into the local unnamed tributary Skippack Creek, or to
the local sewage treatment plant if approved» The point of
discharge shall be determined during the remedial, design and
shall be approved by EPA in consultation with PADER. The
discharging of water shall comply with requirements of NPDES
standards (or with applicable pretreatment standards for a
treatment plant). These requirements are found in Pennsylvania
Water Quality regulations at 25 Pa. Code Chapters 16, 92 and 93
38
AR30J505
-------
(the Skippack Creak drainage basin is listed in Section 93.9f)
The specific discharge criteria shall be established by EPA
during Remedial Design.
Quality Control Monitoring
Parameters, frequency and type of monitoring of process
variables including discharge water and air from the air stripper
shall be determined during Remedial Design and shall be approved
by EPA.
Monitoring of Cleanup
A system of monitoring wells shall be designed to monitor
the cleanup progress throughout the plume and shall be installed.
Number and locations of these monitoring wells shall be approved
by EPA in consultation with PADER. These wells will be used to
evaluate the effectiveness of this interim action for ground
water. The data collected from these wells will be evaluated to
determine whether or not the interim ground water extraction
system is sufficient to remediate the contamination in the entire
plume area. This determination will be made as part of the final
action on this operable unit. •
The monitoring wells that are installed shall be sampled •
quarterly for the first two years and semi-annually thereafter
until the levels of contaminants of concern in these wells have
reached the background levels. Once background cleanup levels
are reached throughout the plume, these wells shall be sampled
for twelve consecutive quarters and if contaminant levels remain
at these levels, the operation of the extraction system shall be
shutdown. Semi-annual monitoring of the ground water shall
continue for five years. If subsequent to the extraction system
shutdown, monitoring shows the ground water concentrations of any
contaminant of concern to be above background or other agreed
upon cleanup level, the system shall be restarted and continued
until the levels have once more been attained for twelve
consecutive quarters. Semi-annual monitoring shall continue
until EPA determines in consultation with PADER that contaminants
have reached stable levels below background. If the final
remedial action indicates that additional extraction and/or
monitoring wells are needed, the entire monitoring systems shall
be reevaluated and redesigned in accordance with the standards
specified in the Record of Decision for that final action.
In addition to monitoring the ground water quality, EPA
shall also conduct an initial delineation and functional
assessment of wetlands in the area. As part of the monitoring,
EPA will conduct an annual assessment of the vegetation and
functional continuity of the identified wetlands to ensure that
the pumping of ground water does not adversely impact these areas
through lowering of the water table. Surface waters potentially
39
4R30I506
-------
affected by the discharge of treated water or ground water will
also be monitored initially to ensure that no adverse impacts are
occurring.
Five Year Review
Because DNAPLs may remain on-Site as a source of future
ground water contamination, Five Year Reviews shall be conducted
after the remedy is implemented to assure that the remedy
continues to protect human health and the environment. A Five
Year Review work plan shall be drafted after the remedy is
implemented and shall be approved by EPA in consultation with
FADER.
The five-year review required by Section 121 of CERCLA, 42
U.S.C. S 9621, is applicable to the selected remedy, and this
requirement will continue as long as residual contamination
remains above the Maximum Contaminant Level for PCE.
The Pennsylvania Hazardous Waste Management Regulation,
codified at 25 Pa. Code SS 264.90-264.100, requiring cleanup of
ground water to background quality is a relevant and appropriate
requirement for this action. The selected alternative is being .
taken as an interim action. The eventual goal of the ground
water operable unit is to attain compliance with this ARAR. EPA
will evaluate the effectiveness of the selected combination of
alternatives, and will issue a final Record, of Decision on this
operable unit which will either commit to the goal of achieving
this requirement, or provide a rationale for why it. cannot be
achieved in this case.
Implementation of Alternatives 4 and 5 will ensure that MCLs
for PCE continue to be attained at the locations where this
standard is relevant and appropriate (i.e., in the drinking water
aquifer) . These Alternatives will comply with the Erosion
Control Regulations, codified at 25 Pa. Code Chapter 102.
-Sito^ activities of the selected alternative will also be
performed in compliance with all other applicable legal
requirements (e.g., worker health and safety laws and
regulations, see 40 C.F.R. S 300.150) that are not within the
scope of federal environmental or state environmental or facility
siting laws.
10. Statutory Determinations
Under its legal authorities, EPA's primary responsibility at
CERCLA Sites is to undertake remedial actions that achieve
adequate protection of human- health and the environment. In
addition, Section 121 of CERCLA establishes several other
statutory requirements and preferences. One such requirement is
that, when complete, the Selected Remedy implemented at the Site
40
AR30I507
-------
must comply with applicable or relevant and appropriate
environmental standards established under federal and state
environmental lavs unless a statutory waiver is justified. The
Selected Remedy also must be cost-effective and utilize permanent
solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable.
Finally/ the statute includes a preference for remedies that
employ treatment as a principal element to permanently and
significantly reduce the volume, toxicity, or mobility of
hazardous wastes. The following sections discuss how the
Selected Remedy meets these statutory requirements.
A. Protection of Tnn Health and the Environment
The Site, in its existing condition, does present a
potential threat to human health or the environment. Levels of
PCE in ground water have been identified at levels that exceed
the MCLs. Levels found in the soil are continuing to contribute
to contamination in the drinking water aquifer. If the plume
continues to spread, additional wells may be affected.
Therefore, the alternatives selected here are designed to remove
the potential threat to the drinking water supply. Removal of
the contaminated soil will eliminate the source of the ground }
water contamination, and pumping and treatment of the
contaminated ground water will contain the plume and eventually f-
reduce ground water concentrations to acceptable levels.
Implementation of the selected remedies will protect human health
and the environment by eliminating the source of contamination
and protecting drinking water supplies in the area.
B. Compliance with Applicable or Relevant and Appropriate
Requirements
The selected alternatives will comply with the ARARs
discussed in connection with these alternatives in Section 7 and
9 of this ROD. For the ground water operable unit, which is an
interim action, achievement of background levels of contamination
is the goal of the remediation. This goal will be reevaluated in
the final ROD that will be issued in the future.
C. Cost-Effectiveness
Section 300.430(f ) (1) (ii) (D) of the NCP, 40 C.F.R. S
300. 430 (f) (1) (ii) (D) , requires that the selected remedy be cost-
effective. That section of the NCP states that cost-
effectiveness is determined by first evaluating the following
three of the five "balancing" criteria to determine overall
effectiveness of the remedy: long-term effectiveness and
permanence, reduction of toxicity, mobility, or volume through
treatment, and short-term effectiveness. Overall effectiveness
is then compared to cost to ensure that the remedy is cost-
effective. A remedy is cost-effective if its costs are
41
^30/508
-------
proportional to its overall effectiveness.
The remedy selected for the soil contamination operable unit
is expected to be cost effective in protecting human health and
the environment. Although Alternative 3 was the most expensive
alternative evaluated, it is the only one of the three that
effectively removes the contamination that is contributing to
ground water contamination. If the soil cleanup is not
completed, the cost for cleanup of ground water will be much
greater. It is more cost-effective to eliminate the source of
the contamination in the soil rather than to treat the ground
water once it becomes further contaminated. Other treatment
alternatives were evaluated during the Feasibility Study, but
were screened out due to high costs or technical infeasibility.
The three areas needing to be addressed are too small for several
of the treatment techniques, and the soil conditions are not
conducive to others.
For the ground water operable unit, Alternatives 4 and 5 are
the third and most expensive alternatives, respectively. The
combination of the two is more expensive than all the other
alternatives. However, the cost estimates are believed to be an
absolute maximum. Costs are based on separate treatment systems:
for each alternative; a combined system for both would
significantly lower costs. If extracted water is discharged to a
sewage treatment plant without treatment, an even greater savings
will be realized. Although the selected alternatives are
expensive, they are necessary to protect drinking water in the
area. High.levels of PCE are still entering the Granite Knitting
Mills well in the upper interval. Levels of PCE have been found
in intervals of Well S-9 ranging from 9 to 24 ppb. There is a
possibility that pockets of higher contamination exist in the
area around Well S-9. Therefore, pumping this well will draw
this contamination out of the drinking water aquifer, and pumping
the shallow interval of the Granite well will prevent this higher
level contamination from entering the aquifer. Therefore, this
remedy is cost-effective.
P. Utilization of Permanent Solutions and Alternative Treatment
(or Resource Recovery) Technologies to the MaxUnm^* Extent
Practicable
The alternatives selected are permanent solutions to the
contamination at the Site. The soil excavation and removal will
permanently eliminate the source of the ground water
contamination. The pump and treat system for the ground water
contamination will permanently remove the contaminants from the
aquifer to the extent practicable. Once this treatment system
has operated for a sufficient- time to reduce the PCE levels in
ground water to acceptable levels and maintain these levels, this
will be a permanent solution.
42
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Various treatment alternatives were evaluated during the
feasibility study. However, none of these alternatives were
found to be cost effective or technically feasible for this Site.
No resource recovery options were feasible for the conditions
present at this Site. .
Consequently, EPA has determined that the selected remedies
utilize permanent solutions and alternative treatment
technologies to the maximum extent practicable, while providing
the best balance in terms of long-term effectiveness and
permanence; reduction of toxicity, mobility, or volume through
treatment; short term effectiveness; implementability; and cost.
E. Preference for Treatment as a Principal Element
The remedy selected for the source control operable unit
does not satisfy the CERCLA preference for remedies that
incorporate treatment as a principal element. Although EPA
reviewed several treatment technologies for application to this
Site, EPA believes that none of these treatment technologies is
practicable for use in cleaning up this Site. This is primarily
due to the fact that three different properties would require
treatment, and the quantity of soil at each property is very
small. Soil conditions at the Site limit or eliminate the use of
some possible soil treatment techniques. Further, EPA determined
that the treatment alternatives did not provide the overall best
balance in meeting the nine criteria for selection of remedial
actions.
•y - -
For the ground water operable unit, treatment has been
selected as a principle element in the remedy for the
contaminated ground water. The water extracted from the wells
will be treated at the Site prior to discharge, or will be
treated in a sewage treatment plant if direct discharge to a
plant is found to be acceptable.
11. po^ym^ntation of Significant Changes
The Proposed Plan for the North Penn Area 1 Site was
released in June 1994. The Proposed Plan identified excavation
and offsite disposal of contaminated soil (Alternative 3) for
operable unit 1, and pumping and treating of the upper interval
of the Granite Knitting Mills well and the entire Well S-9
(Alternatives 4 and 5) as an interim action for operable unit 2,
as the preferred alternatives. EPA reviewed all the verbal
comments received at the public meeting (no written comments were
received). Upon review of these comments, it was determined that
no significant changes to the remedy, as it was originally
identified in the Proposed Plan, were necessary.
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* Responsiveness summary
North Penn Area i site
Souderton, Montgomery county, Pennsylvania
This Responsiveness Summary documents public comments received
by EPA during the public comment period on the Proposed Plan for
the North Penn Area 1 Site ("the Site"). It also provides EPA's
responses to those comments. The Responsiveness Summary is
organized as follows:
SECTION I Overview
This section summarizes recent actions at the Site and the
public's-response to the remedial alternatives listed in the
Proposed Remedial Action Plan (Proposed Plan). The Proposed Plan
outlines various cleanup alternatives available to address Site
contamination and highlights EPA's preferred alternatives.
SECTION II Background on Community involvement
This section provides a brief history of community interest in
the site and identifies key issues.
SECTION III Summary of Major comments and Questions Received
During the Public Meeting and EPA's Responses
This section documents comments and questions from the public
that were voiced during the public meeting regarding the Site and
EPA's responses to them.
I. Overview
The public comment period on the Proposed Plan for this Site
began on July 6, 1994 and ended on August 4, 1994. EPA held a
public meeting at the Souderton Municipal Building on July 14,
1994. Copies of the newspaper advertisements announcing the
meeting and comment period are attached.
The following EPA participants were present at the meeting:
Amy Barnett Community Relations Coordinator
Gregory Ham Remedial Project Manager
At the meeting, EPA representatives summarized the iesults of
the Remedial Investigation (RI), Feasibility Study (FS), and the
Risk Assessment performed for the Site. EPA presented the
preferred alternatives to address Site contamination. The Proposed
Plan addressed the areas of soil contamination, and the groundwater
contamination plume. The preferred alternatives for the Site
presented to the public were the excavation and offsite disposal of
soil from the three affected facilities, and the pumping and
JR30I5II
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treatment of groundwater from two wells near the center of the
plume.
The public was given an opportunity to ask questions or submit
written comments on the alternatives outlined in the Proposed Plan
and the results of the RI/PS for the Site. The comments from the
public meeting, and EPA's responses, are summarized in Section III
of this document. They are not presented in the order received at
the meeting. The complete transcript of the public meeting is
contained in the Administrative Record file for the Site.
No written comments were received during the comment period.
SECTION II Background on Community Involvement
This Site was placed on the National Priorities List on March
of 1989. Upon being listed, EPA began the Remedial
Investigation/Feasibility Study (RI/FS) process, and in March of
1992 EPA issued a fact sheet summarizing the status of the Site and
EPA's plans for the RI/FS at this Site. EPA representatives also
were present at the April 6, 1992 Borough Council meeting to brief
the Council and answer any questions on Site plans and activities.
For this Record of Decision, a formal public meeting, as
discussed above, was held. At the public meeting, attendees were
invited to ask questions directly to EPA representatives about the
Proposed Plan and the work that has been done at the Site during
the Remedial Investigation/Feasibility Study, and about the
preferred alternatives for cleaning up the Site. The main concerns
expressed at this meeting were about the liability for the Site and
the costs of cleaning up the contamination.
SECTION III Summary of comments and Questions from the Public
Meeting
The comments raised at the public meeting primarily concerned
three areas: liability, recovery of costs, and the nature of the
proposed remedial actions. The issues raised, and the EPA
responses to these issues, are presented below.
Comment #1; When determining liability for site cleanups, the
Superfund law presumes that people are guilty, especially in the
case of current owners of a property where contamination occurred
under previous ownership.
Response: Under the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA, commonly known as
Superfund) there are four primary categories of liable parties:
owners, operators, arrangers for treatment or disposal, or
transporters of hazardous wastes. The owners category- includes
current owners of contaminatecl ;prpperlt/,;j andthose who owned the
property during the time the contamination "occurred or any time
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since the contamination occurred. The intent of the law was to
limit the time spent in determining who was liable for the cleanup
by including a broad liability scheme. This has been one of the
biggest areas of contention of the Superfund law, and is a major
topic in the current Superfund reauthorization discussions. Until
the current law is changed, EPA must carry out the law as currently
written, including provisions for determining liability.
comment #2: When are affected property owners given releases
allowing them to sell or modify their properties?
Response; EPA does not issue "releases" to a property owner
stating that the property is clean and suitable for any purpose.
When EPA determines that a remedial action is needed on a property,
the remediation or cleanup goals are established as part of the
remedial design. Then the remedial action is carried out. Once
the remediation goals are met, a closeout report is issued
summarizing the actions taken, documenting the achievement of the
remediation goals, and discussing the current status of the site.
This report is available to the public, including the owner of the
property. However, EPA does not issue a release.
Comment #3; Are properties removed from the list of potentially
responsible parties (PRPs) once the property is cleaned up?
Response: EPA keeps records of any parties considered to be PRPs
for each site it is working on under Superfund. As the term
implies, these are "potentially" responsible parties. No
conclusive decisions have been made concerning liability just by an
entity being listed as a PRP. In later actions to attempt to get
PRPs to conduct investigations or cleanup actions, or to recover
funds expended, EPA must provide evidence of the PRPs involvement
in the contamination to support such attempts, and the affected
parties have recourse provided for under the Statute.
EPA does not remove PRPs from the list once they are on it,
since the list provides a record of the investigations that have
occurred for each site. This does not mean that the entity
continues to be considered as a "responsible party" when
information shows otherwise.
Comment #4: Does EPA make an effort to recover costs from property
owners or other PRPs?
Response; Yes, EPA does attempt to recover all costs expended to
investigate and clean up sites. In all Superfund cases, EPA
investigates the liability of PRP's and evaluates their financial
status and assets to determine if actions can be taken to recover
costs. This is being done with this Site. The -Agency does not
comment on the possibility of future actions to recover-costs.
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Comment #5; How are costs apportioned among PRPs in the cost
recovery process?
Response; In determining how the costs are to be apportioned, EPA
prepares a complete list of all known PRPs. For the PRPs on the
list, factors such as amount of wastes attributable to each PRP and
ability to pay are considered. From an evaluation of these and
other factors, EPA can sometimes determine an appropriate cost for
each remaining PRP. However, it is important to remember that
under the Superfund law, each PRP remains jointly and severally
liable for any costs.
Comment #6; Are costs billed once the project is completed, or are
interim billings issued?
Response: The way the costs are recovered varies depending on the
situation. Where no remedial action is taken after the Remedial
Investigation/Feasibility study, EPA must initiate legal actions to
recover funds within 3 years of completion. If a remedial action
is initiated, EPA must initiate cost recovery actions within 6
years of the initiation of the action. EPA can also use
administrative processes (demand letters and/or consent agreements)
to initiate cost recovery actions at any time there are outstanding
costs. • . Which route EPA uses depends upon the specific
circumstances of the individual sites. •
Comment #7; How is the priority determined for whether or not a
site gets cleaned up? Could it take 10 years from the time the
decision is made that a remedial action is needed until the actual
cleanup occurs?
Response: Once a site is listed on the National Priorities List,
EPA evaluates the site and determines the appropriate strategy for
investigating the site. It may be divided up into operable units,
with each unit being investigated in sequence, or the entire site
may be addressed in one action. Each site or operable unit
proceeds according to schedules that reflect the nature and
complexity of the problems being addressed. If an immiment health
threat is discovered, an emergency removal action can quickly be
initiated. The priority for cleanup depends on a number of
factors, such as available funding, workloads, number of sites
being investigated, etc.
Once the Record of Decision (ROD) is issued determining that
a remedial action is necessary, the action is usually taken within
a year or so of the ROD. It would be unusual for a cleanup to be
initiated 10 years after the ROD.
Comment #8; The soil excavation would leave a large hole at each
property. What would be done? Much of the area at Parkside is
reportedly fill consisting of concrete blocks. What would be done
with that?
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Response; The details of the soil cleanup will be presented in the
Remedial Design, which will be released to the public before the
cleanup is initiated. In general, EPA attempts to restore
properties to conditions existing prior to the action taken. Any
excavation areas will be filled with clean fill, with contours
restored to previous levels. The soil will be sampled as the
excavation continues, and only soil or other fill material
contaminated above the cleanup levels will be removed. If any
concrete blocks are encountered, the surfaces may be tested for
contamination, and a decision would be made based on the test
results what action would be needed to dispose of these. All
contaminated soils or other materials will be shipped to an
approved disposal facilited permitted to accept such materials.
Comment #9; Would discharging the contaminated water extracted
from the wells to the sewage treatment plant create a hazard for
the treatment plant?
Response; Discharging of the contaminated water to the treatment
plant would only be done if the appropriate approvals were obtained
from the authority operating the plant. All applicable,
substantive pretreatment standards or discharge limitations for the
treatment plant would have to be met. If the discharge from the
pumped wells would adversely affect the operation of the treatment
plant, than other treatment alternatives would have to be
implemented.
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