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- PROPOSED PLANCOMMODORE SEMICONDUCTOR/MOS SITE
LOWER PROVIDENCE TOWNSHIP, PENNSYLVANIA
Introduction
This Proposed Plan has been prepared by the U.S.Environmental
Protection Agency (EPA), Region III to provide thepublic with the
opportunity to review and comment on the remedialaction for
addressing the groundwater contamination at theCommodore Site
("Site"). This document contains an evaluation ofthe remedial
alternatives considered by EPA; identifies thealternative preferred
by the EPA and explains the reasons forthis preference. In
addition, the plan explains how the publicmay participate in the
decision-making process and providesaddresses and telephone numbers
for the appropriate EPA contacts.This action is the only action
planned for the site.
This document is issued by the EPA, the lead agency for
SiteSuperfund activities. The EPA, in consultation with
thePennsylvania Department of Environmental Resources (PADER),
willselect a remedy only after it has reviewed and considered
thecomments received during the public comment period.
The EPA is issuing this Proposed Plan as part of its
publicparticipation responsibilities under Section 117(a) of
theComprehensive Environmental Response, Compensation and
LiabilityAct (CERCLA). This plan highlights key information that
iscontained in the Remedial Investigation and Feasibility
StudyReport ("RI/FS") but does not serve as a substitute for
thesedocuments. The RI determines the nature and extent
ofcontamination at the Site and estimates the risks posed by
theSite to human health and the environment. The FS then
examinescomprehensive cleanup alternatives. The RI/FS Report
iscontained in the Administrative Record File for the Site.
TheAdministrative Record File consists of technical reports
andreference documents used by EPA to compile the Proposed
Plan.These documents are available to the public at the
localinformation repositories:
Lower Providence Community Library2765 Egypt RoadAudubon, PA
19405(215) 666-6640
and
Montgomery County Planning Commision County CourthouseOne
Montgomery PlazaNorristown, PA 19404(215) 278-3733
A copy of the Administrative Record File is also availafihS waQ
OEelH 8
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Region III Offices; for an appointment contact:
Anna ButchAdministrative Record CoordinatorU. S. Environmental
Protection Agency, Region III841 Chestnut BuildingPhiladelphia, PA
19107(215) 597-3037
EPA and PADER invite the public to review the materialsavailable
and to comment on the Proposed Plan which begins onJuly 21, 1992
and ends on August 20, 1992.
EPA, in consultation with PADER, may modify the
preferredalternative or select another response action presented in
thisplan, based on new information or public comments.
Therefore,the public is encouraged to review and comment on
thealternatives identified here. The final remedy for ground
waterremediation and for an alternate water supply will be selected
ina Record of Decision, which shall also be available for review
atthe local repository. This is the only action planned for
thisSite.
SITE BACKGROUND AND HISTORY
The Commodore Semiconductor Group ("CSG") Site islocated in the
Valley Forge Corporate Center (VFCC) inNorristown, Lower Providence
Township, Pennsylvania. TheCommodore Semiconductor Group facility
is located at 950Rittenhouse Road in Norristown. The facility is
approximatelyone mile north of the Schuylkill River. The facility
is borderedon the northwest by Rittenhouse Road, on the northeast
by VanBuren Avenue and on the southeast by Adams Avenue. The
GeneralWashington Country Club golf course occupies all the
propertyimmediately west of the facility on Rittenhouse Road with
theremainder of the surrounding property being occupied
byindustrial and commercial facilities. Private residences
arelocated approximately one-half mile from the facility in
alldirections. (See Figure 1, Location of CSG Site)
The facility was constructed in 1970 by Alien-BradleyCorporation
and leased to MOS Technology, Inc. In 1976, CSG adivision of
Commodore Business Machines purchased the stock ofMOS Technology,
Inc. The facility continued to operate under thename of MOS
Technology. In April 1978 Alien-Bradley sold theproperty, including
the building to Commodore Business Machines.Currently CSG operates
the facility.
The facility was built to manufacture semiconductor chipsused in
the production of computers, calculators, and otherelectronic
equipment. At the time the original building wasconstructed an
underground concrete storage tank, reported to
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hold 250 gallons of liquid was installed adjacent to
thesoutheast side of the building. The concrete tank was used
tostore a waste solution known to contain trichloroethene (TCE)
andother solvents used in the manufacturing of semiconductor
chips.Based on PADER field notes, the concrete tank was reported
tohave leaked in 1974. MOS Technologies discontinued the use ofthis
tank and installed an unlined steel tank undergroundadjacent to the
concrete one in 1975.
In 1978, the Audubon Water Company (AWC), suppliers of waterto
the Village of Audubon and Lower Providence Township, detectedTCE
in two of its wells located at the Site. PADER identifiedthe
Commodore facility as a possible TCE source. In the fall of1979 the
underground tanks were excavated. Tests conductedduring the
excavation revealed very high levels of TCE and PCE inthe soil
directly below the underground storage tanks and in thesurrounding
groundwater. In 1979 Commodore replaced these tankswith a waste
solvent collection system consisting of a tankwithin a lined vault.
In 1981 Commodore discontinued the use ofTCE in its manufacturing
process. The company also installedgroundwater monitoring wells and
began a sampling program.
At PADER's direction measures to reduce TCE
concentrationsstarted in early January 1981. From 1981 to 1983
public supplywell numbered VFCC-4 (Audubon Water Company is the
owner) waspumped and the ground water was spray irrigated.
Sprayirrigation is a practice consisting of spraying
contaminatedwater on a field and allowing volatile organics to
evaporate intothe air. Commodore held a state permit for the spray
irrigationsystem. In February 1984, CBM purchased and installed an
airstripper on VFCC-4. Commodore also installed an additional
airstripper on Commodore property to treat shallow ground water
thatis collected in the french drain system underneath the portion
ofthe building which was expanded in 1985. In 1984, also atPADER's
direction, Commodore began a residential sampling programand
installed whole-house carbon filter systems on residenceswith 1 ppb
of organics detected. A total of 23 residences weresupplied with
filters.
In February 1984 EPA performed a site inspection of theCommodore
Facility. A Preliminary Assessment and SiteInvestigation were
completed on 12/5/86 and 12/15/86respectively. The sampling results
revealed the presence of TCEand showed that TCE was present in
nearby residential wells. TCEand TCE related compounds were also
found in the groundwater,surface water, and soil samples taken from
the Site. TheCommodore Facility was proposed for inclusion on the
NationalPriorities List in January 1987. The Site scored a 42.35
underEPA's hazard ranking system and in October 1989, the
CommodoreSite was made final on the NPL.
Commodore Business Machines Inc., was identified as a
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•s
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Potentially Responsible Party (PRP), and conducted a
RemedialInvestigation/Feasibility Study (RI/FS) at the Site
pursuant tothe terms of an Administrative Order By Consent (Docket
No. III-88-09-DC) signed by the PRP and EPA in July 1988. The
purpose ofthe RI/FS is to characterize the type and extent of
contaminationrelated to the Site, quantify any existing or
potential humanhealth risks, and evaluate potential environmental
risks, and todevelop alternatives to address the contamination
problems.
SCOPE AND ROLE OF THE ACTION
The goal of the selected remedy is to prevent furthermigration
of the contaminants in the groundwater; to recover andtreat
contaminated groundwater; to provide a permanent alternatewater
supply for the affected and potentially affectedresidential well
users southwest of the Site; to prevent theingestion of and dermal
contact with contaminated groundwater andthe inhalation of vapors
from contaminated groundwater; and torestore contaminated
groundwater to its beneficial uses, ifpracticable. The remedy also
provides for continued maintenanceof carbon filters currently
provided by the PRP in theresidential area southeast of the
Commodore site.
The remedial alternatives under consideration are summarized
inthis proposed plan. The RI/FS report presents a more
thoroughdescription and evaluation of these alternatives. Based on
newinformation or public comments, EPA, in consultation with
thePADER, may modify the preferred alternative or select
anotherresponse action presented in this Proposed Plan and the
FSReport. The public is encouraged to review and comment on
allalternatives identified.
SUMMARY OF SITE RISKS
Data collected during the RI/FS, was used to assess andestimate
the risk that the site would pose to human health andthe
environment if no remedial actions were taken. This processis
called a Baseline Risk Assessment (RA). The RA involvesassessing
the toxicity, or degree of hazard, posed by substancesrelated to
the Site, and involves describing the routes by whichhumans and the
environment could come into contact with thesesubstances. Separate
calculations are made for those substancesthat can cause cancer
(carcinogenic) and for those that can causenon-carcinogenic health
effects.
The National Oil and Hazardous Substances Contingency Plan(NCP)
established acceptable levels of carcinogenic risk forSuperfund
sites ranging from 1 in 10,000 to l in l million excesscancer
cases. This translates to a risk range of between IxlO"4and IxlO"6.
The NCP also states that sites should pose no non-carcinogenic
threat, which EPA defines as a chronic dose AR302252exceeding the
reference dose, as indicated by a hazard
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index,(HI), greater than 1. The hazard index identifies
thepotential for the most sensitive individuals to be
affectedadversely by noncarcinogenic chemicals. If the hazard
indexexceeds one (1.0), there may be concern of
potentialnoncarcinogenic effects.
The medium of concern is groundwater. Chemicals of concernat the
site are volatile organic compounds (VOCs). Chemicalsdetected in
the groundwater are listed below with theirrespective maximum
contaminant level (MCL) or in the absence ofan MCL, a risk-based
calculation. Not all the contaminants weredetected at each of the
receptor location used to evaluate risks.Attachment 1 (following
page 19) summarizes the wells with majorMCL and proposed MCL
exceedances.
(MCL ppb)Bromodichloromethane 100chloroform 1001,2
Dichlorobenzene 751,4 Dichlorobenzene 6001,1 Dichloroethane 810*1,1
Dichloroethene 71,2 Dichloroethene 70tetrachloroethene 51,1,1
Trichloroethane 200Trichloroethene 5vinyl chloride 2
*Non-carcinogenic health-based concentration.
Persons who utilize untreated water from the public supply
wellsor from private wells are identified as the population at
risk.The primary routes of exposure to contaminants in
groundwateroccurs through ingestion, inhalation of volatiles,
dermalabsorption and inhalation of volatiles in outdoor air due
toexisting air stripper emissions.
The risk assessment was conducted assuming residents,
areaworkers and country club members would use groundwater
withouttreatment. The NCP requires that the risk assessment
considerexposure scenarios both for current land use and for
aconservative reasonable future use. The exposure
scenariosdeveloped to evaluate the risk are the following:
1. Current private residential wells2. Current public
residential water supply wells3. Future George Washington Country
Club (GWCC) residential well
(This scenario assumes country club will undergo
residentialdevelopment)
4. Current GWCC member5. Current GWCC worker6. Current Valley
Forge Corporate Center (VFCC) worker
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7. Future VFCC worker
Risks related to the Site are summarized in Table 1. The
risknumbers represent the total risks from all the routes of
exposureto contaminants in groundwater which occurs through
ingestion,inhalation of volatiles, dermal absorption, and
inhalation ofvolatiles in outdoor air due to the existing air
stripperemissions near the site.
TABLE 1Summary of human health risk results
Scenario
PrivateResidentialWell
PublicResidentialWellGWCC FutureResidentGWCC MemberGWCC
WorkerVFCC CurrentWorkerVFCC FutureWorker
Childnon-cancertotal chronicHI
0.27
:W?T'î :¥riK¥A§J
1.0
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Adultnon-cancertotal chronicHI
0.082
0.37
0.31
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0.0036
0.055
0.93
Adult & Childcancer totallifetime risk
2xlO~5
4xlO~5
•̂̂ ^̂ Ê̂ Ŵ̂ ^
IxlO"6
IXlO"7
IxlO"5
5xlO~5
Risks from one future use scenario and one current usescenario
exceed the NCP range: lifetime cancer risk for a GWCC
I future resident is 1.4 x 10~4, and the chronic hazard index
forI a child using public water is 1.2.i • •
I Table 2 summaries the chemicals which collectively contribute;
over 90% of the risks for each of the scenarios evaluated.
AR3Q2251*
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TABLE 2Summary of chemicals contributing over 90% of risk
Private ResidentialWell
Public ResidentialWellGWCC Future Res.
GWCC MemberGWCC Work
VFCC current worker
VFCC future worker
Child non-cancer
1,2 DCE,TCE,(Ch)
TCE, 1,2 DCE
TCE, 1,1 DCE
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1,1,1 TCA;1,2 DCE
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Adult non-cancer
1,2 DCE, TCE(Ch)
TCE, 1,2 DCE
TCE;1,1, 1TCA
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(Ch)
1,1,1 TCA;1,2 DCE
TCE; PCE;1,1 DCE
Adult & childcancer
1,1 DCE, TCE,(Ch)
1, 1 DCE,
1,1DCE;VC;TCE
(Ch) ; BCM;TCE-
BCM, (Ch) TCE
1,1 DCE; TCE;PCE
TCE; 1,1 DCE;VC; TCE
BCM - BromodichloroemethaneCh - ChloroformDCE -
DichloroetheneTCE - TrichloroetheneTCA - TrichloroethanePCE -
Tetrachloroethene
There are several shallow monitoring wells at the Site thatare
screened in the overburden. These wells have greaterconcentrations
of contaminants than the deep wells screened inthe bedrock. However
their yields are so low that it is notplausible that this portion
of the aquifer could be used as adrinking water source in the
future. Therefore exposure to thesewells was not evaluated in the
risk assessment. Neverthelesscleanup of this shallow aquifer is
necessary to mitigate thepotential migration of contaminants to the
bedrock aquifer.
Ingestion and dermal contact with Site soils under a
workerexposure scenario was evaluated. The concentrations of
thecontaminants in soils did not exceed risk-based
concentrationlevels.
There are air strippers on four public supply wells near theSite
and the french drain system beneath the CSG building.
AR302255
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Emissions from these air stripping towers were modeled
toevaluate risks from inhalation of outdoor air for all theexposure
scenarios. Risks were well below the 10~6 risk.
Based upon consultation with State and Federal
agenciesknowledgeable about threatened or endangered species in
theCommonwealth of Pennsylvania, EPA has determined that
noendangered species or sensitive habitats are near the Site.
Five surface water samples were collected from theintermittent
part of Lamb Run which is the only stream near theSite. Samples
were analyzed for volatile organics. TCE, PCE,and 1,2 DCE were
detected. The concentrations detected are wellbelow ambient water
quality criteria for those contaminants.
Actual or threatened releases of hazardous substances fromthis
Site, if not addressed by the preferred alternative or oneof the
other remedial measure considered, present a current orpotential
threat to public health, welfare, or the environment.
SUMMARY OF REMEDIAL ACTION ALTERNATIVES
The draft RI/FS dated February 1992 discusses the
alternativesevaluated for the Site and provides supporting
informationleading to alternative selection by EPA.
Five remedial alternatives were carried through a
detailedanalysis in the Feasibility Study. These are numbered
tocorrespond with the numbers in the RI/FS Report. Thealternatives
for the Site are the following:
Alternative 1: No action
I Alternative 2: Institutional controls and connection to
publicj water supply
Alternative 3: Commodore property deep groundwater Recovery
andExisting off-property deep groundwater recoverywith treatment by
air stripping (option A) orcarbon absorption (option B) and
institutionalcontrols
Alternative 4: Commodore property deep and shallow
groundwaterrecovery and existing off-property deepgroundwater
recovery with treatment by airstripping (option A) or Carbon
adsorption(option B) and institutional controls
Alternative 5: Commodore property deep and shallow
groundwaterrecovery and modified off-property deep fl D
ogroundwater recovery with treatment by air * ̂
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10 •stripping (option A) or carbon adsorption(option B) and
institutional controls.
ALTERNATIVE 1: NO ACTION
The Superfund Program requires that the "no action"alternative
be evaluated at every site to establish a baselinefor comparison.
Under this alternative, no action other thanonsite groundwater
monitoring would be implemented. Maintenanceof the whole-house
carbon filtration systems on the 23residential wells would be
discontinued and no monitoring ofresidential wells. Under this
alternative the seven monitoringwells will be sampled
semi-annually. Because this alternativewould result in contaminated
groundwater remaining on site, 5-year site reviews would be
required. Zero time required forimplementation. There are no
capital costs for this alternative.Costs of long-term monitoring of
groundwater is estimated at$26,000 per year. The 30 year present
worth cost is $277,400.
ALTERNATIVE 2: institutional Controls and connection to
thePublic Water Supply
The intent of this alternative is to prevent any unacceptable
^bpresent and future risk associated with potable and nonpotable
F̂use of contaminated groundwater. Residences south of the Site
onRittenhouse Road and on Audubon Road between Rittenhouse Road
andThrush Line would be connected to the public water supply.
Forthe costing of this alternative, short-term
institutionalcontrols, which would last two years, include
continuedmaintenance of the existing whole-house carbon filtration
systemsto the southwest plus the installation of one additional
system.In addition maintenance of whole-house carbon filtration
systemswill continue for the residences southeast of the Site which
areidentified as Group 2 in the Feasibility Study. It is
assumedthat 2 years will be sufficient to confirm the source of
thecontamination in these residential wells.
Long-term institutional controls include implementation of
along-term groundwater monitoring program, upgrading of
securitylocks on all wells used for monitoring and assumes that
theresidences in the area defined as Group three which are
locatedon Rittenhouse Road south of the Site and on Audubon Road
betweenRittenhouse Road and Thrush Lane would be connected to the
publicwater supply. Development of groundwater management zones
isincluded in institutional controls to establish areas in the
sitevicinity where well installations and permit restrictions will
berequired. The estimated implementation time for installation
ofadditional water lines in the community near the site is 2
years.
Capital Costs: $125,500 anonooRO & M Cost/Year (Years 1-2):
$232,600 flnoU
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11' O&M Cost/Year (Years 3-30): $211,800| 30 Year Present
Worth: $2,564,900
' ALTERNATIVE 3: Commodore property deep groundwater extraction;
with treatment by air stripping (option A) or carbon
absorption(option B) and off-property deep groundwater extraction
withexisting treatment.
:!
i In addition to the elements described in Alternative 2 whichi
provide public health protection, Alternative 3 provides for on-l
and off-property extraction of contaminated groundwater. Thei
objective of on-property deep groundwater extraction is toj provide
migration control and recovery of onsite deepI groundwater.
Off-property extraction of the public water supply; will also
continue to provide interception and recovery of thei plume
offsite. The Audubon Water Company water supply wells: Audj 3, Aud
5, and VFCC-2 will be utilized for the off-propertyi extraction.
The off-property water supplies will continue to be| treated by
their existing air strippers. Treated water from| onsite extraction
may be used in the CSG plant during operation,'I discharged to the
POTW or provided to the public water supply.i
I Under Option A, the existing onsite air stripper with
vaporphase carbon emission control will be used to treat
thecontaminated groundwater from the deep onsite recovery well
and
, the French drain.
! Under Option B, the existing stripper will continue to be;
used for treatment of groundwater from the French drain and ani
aqueous phase carbon treatment system will be used to treat!
contaminated groundwater recovered from the new onsite deep\
recovery well. Air standards for air emissions will beI attained.
Monitoring and 5-year site reviews would be provided; to measure
the effectiveness of the cleanup.ij For costing purposes the
remediation time for this| alternative was based on 30 years (the
maximum period ofI performance used by EPA for costing purposes).
It is anticipated,! however, that this alternative will take more
than 30 years.l| The costs figures presented in Alternatives 3
assume thati the PRPs will reach agreement with the Audubon Water
Company toutilize their existing water supply wells and air
stripper asdescribed above. If existing wells and air strippers can
not beiused then new extraction and recovery wells with air
emissionicontrols will be installed. In this event the costs for^
implementing Alternative 3A or 3B will increase.
\ Implementation time considers the time required to designand
construct the alternative. Implementation time for thisalternative
is estimated between two and five years.
AR302258
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Option A CostsCapital: $375,100O & M/Year (Years 1-2)
$281,200O & M/Year (Years 3-30) is 239,000 per year30 Year
Present Worth: $3,141,000
Option B CostsCapital: $628,100O & M/Year (Years 1-2)
$318,0000 & M/Year (Years 3 -30) is $274,80030 Year Present
Worth: $3,800,400
ALTERNATIVE 4: Commodore property deep and shallow recovery
withtreatment Option A or Option B and existing off-property
deeprecovery with existing treatment
This alternative includes all the elements described
inAlternative 3 as well as extraction and treatment of
shallowgroundwater using three existing on-property monitoring
wells.The primary objective for the Commodore property recovery is
toprovide a hydraulic control that will minimize
off-propertymigration of VOCs and recover groundwater near the
source areas.The supplemental on-property shallow recovery wells
will recoverthe higher concentration VOCs before they migrate down
to thedeep aquifer. By extracting from both shallow and
deepgroundwater on the Commodore property the overall volume of
waterextracted over the life of remediation should be reduced as
wellas the length of the remediation. Federal and State
airstandards for air emissions will be attained.
Groundwatermonitoring and five-year site review would be provided
to measurethe effectiveness of the cleanup.
Under Option A, recovered water from a new deep groundwaterwell,
(RW-1), the French Drain and wells MOS 11,14, and 15 willbe treated
in the existing air stripper with vapor phase carboncontrol.
Under Option B, an aqueous phase carbon treatment systemwill be
used to treat contaminated groundwater recovered from
theon-property deep and shallow wells.
For costing purposes the remediation time for thisalternative
was based on 30 years (the maximum period ofperformance used by EPA
for costing purposes). It is anticipated,however, that this
alternative will take more than 30 years.
The costs figures presented in Alternative 4A or 4B assumethat
the PRPs will reach agreement with the Audubon Water Companyto
utilize their existing water supply wells and air stripper
asdescribed above. If existing wells and air strippers can not
beused then new extraction and recovery wells with air emission
AR302259
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controls will be installed. In this event the costs
forimplementing Alternative 4A or 4B will increase.
Implementation time considers the time required to design
andconstruct the alternative. Implementation time for
thisalternative is estimated between two and five years.
Option A CostsCapital - $375,1000 & M/Year (1-2 years) -
$292,500O & M/Year (3-30 years) - $250,30030 Year Present Worth
- $3,346,400
Option B CostsCapital - $713,600
' O & M/Year (1-2 years) $348,400O & M/Year (3-30 years)
$306,20030 Year Present Worth - $4,236,000
ALTERNATIVE 5 : Commodore property deep and shallow
groundwaterrecovery and modified off-property deep groundwater
recovery with
! treatment by air stripping (option A) or carbon adsorptioni
(option B)
This alternative is similar to alternative 4 except that
off-property deep groundwater recovery is modified such that
off-property pumping maximizes capture within the CSG plume by
I changing the location of one of the off-property pumping
wells.\Instead of utilizing VFCC-2 as in Alternatives 3 & 4 a
newjrecovery well, RW-2, will be utilized to more effectively
recover|the off-property plume. RW-2 would pump at the same rate
thatiVFCC-2 currently pumps thereby supplying the same water
supplyi capacity. This pumping scenario is expected to recover
theihighest rate of VOCs while maximizing the use of the local
waterI resources. For costing purposes it is assumed that the
water|extracted from RW-2 will be piped to the existing air
stripperjnear VFCC-2 and air emission controls will be required.
Federal|and State air emission standards will be attained.
Groundwateri monitoring and five-year site reviews will be required
to measure|the effectiveness of the cleanup.
i Under Option A recovered water from a new on-property
deepigroundwater well, (RW-1), the French Drain and wells MOS
11,14,iand 15 will be treated in the existing air stripper with
vaporiphase carbon control. Existing treatment on Aud 3 and 5 would
bejused. For, the additional deep well off-property, RW-2,
the'existing stripper at VFCC-2 with vapor phase carbon will be
used!for treatment.
I Under Option B, treatment of combined groundwater from RW-11,
and shallow wells, MOS 11, 14, 15, and the French drain will
AR302260
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be treated using aqueous phase carbon control. Treatment at
Aud3, 5 and RW-2 are the same as in Option A
For costing purposes the remediation time for thisalternative
was based on 30 years (the maximum period ofperformance used by EPA
for costing purposes). It is anticipatedthat this alternative will
take 25 years.
The costs figures presented in Alternative 5A or 5B assumethat
the PRPs will reach agreement with the Audubon Water Companyto
utilize their existing water supply wells and air stripper
asdescribed above. If existing wells and air strippers can not
beused then new extraction and recovery wells with air
emissioncontrols will be installed. In this event the costs
forimplementing Alternative 5A or 5B will increase.
Implementation time considers the time required to designand
construct the alternative. Implementation time for thisalternative
is estimated between two and five years.
Option ACapital Costs: $619,000O & M (0-2 years) $448,800O
& M (3-30 years) $406,60030 Year Present Worth $5,271,700
Option BCapital Costs: $876,000O & M/Year (0-2years)
$513,800O & M/Year (3-30 years) $469,70030 Year Present Worth
$6,243,400
EVALUATION OP ALTERNATIVES
This section includes a summary of the evaluation of
thealternatives identified above. This section also contains
adiscussion of why EPA has selected the "Preferred
Alternative."
EPA's preferred alternative fox- addressing contamination atthe
Commodore Semiconductor Site is Alternative 5A. While thegoal of
this alternative is to remediate groundwater tobackground levels,
the ability to achieve cleanup levels at allpoints throughout the
contaminated groundwater plume cannot bedetermined until the
extraction system has been implemented.This alternative would
protect public health and the environmentby treating and
discharging water at safe levels, which are belowthe MCLs for
drinking water. This alter
Based on current information, this alternative would appearto
provide the best balance of trade-offs among the alternatives
AR302261
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with respect to the nine criteria the EPA uses to evaluate
eachalternative. The following section summarizes the performance
ofthe preferred alternative against the nine criteria, noting howit
compares to the other options under consideration.
EPA uses nine criteria to evaluate remedial alternatives.These
criteria include the statutory requirements of Superfund aswell as
other technical, economic and practical factors used toassess the
feasibility and acceptability of alternatives.
These are the nine criteria*:
1. Overall protection of human health and the environment2.
Compliance with "Applicable or Relevant and Appropriate
Requirements" (ARARs)3. Long-term effectiveness and permanence4.
Reduction of toxicity, mobility or volume through
treatment5. Short-term effectiveness6. Implementability7. Cost8.
State Acceptance9. Community Acceptance
i
* see page 19 for Glossary of the Evaluation CriteriaiI These
nine criteria are commonly divided into three groups:I threshold
criteria (1 & 2), primary criteria (3 - 7) andI modifying
criteria (8 & 9). Alternatives must meet the threshold!
criteria before they are evaluated in any further detail. The|
primary criteria are then used to weigh tradeoffs among
thealternatives that pass the threshold test. The
finalconsiderations include comments from the public and the|
Pennsylvania Department of Environmental Resources.ii|i. overall
Protection. Alternatives 3, 4, and 5 are protective!of public
health and the environment. Each of these alternatives]would
provide a public water supply to residences to thejsouthwest of the
site; and continued carbon filter systemmaintenance for those
residential wells with contaminantssoutheast of the site that are
not confirmed to be site related;and will potentially remove
groundwater contaminants down tobackground levels or MCLs.
Alternatives 3, 4 and 5 would prevent
I exposure to groundwater contaminants, protect
uncontaminatedIgroundwater, and potentially restore contaminated
groundwater tojthe background cleanup levels. However the preferred
alternativeshould attain cleanup levels in a shorter time
period.Alternative 2 protects public health but not the
environment'since Alternative 2 does not actively remediate the
groundwater.Alternative 1, The "No Action" alternative would only
provide
I continued monitoring and is not protective of human health
and
AR302262
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the environment, it is not considered further in this analysis
asan option for the Site.
2. Compliance with ARARs.
Alternatives 3, 4, and 5 will comply with applicable or
bothrelevant and appropriate federal and state
environmentalregulations. Alternative 5 should attain compliance
withgroundwater ARARs in less time than Alternatives 3 and
4.Alternative 2 does not comply with federal groundwater
cleanupARARS, or the State's requirement to remediate groundwater
tobackground quality. Since Alternative 2 will not comply
withgroundwater cleanup ARARS, it will not be considered further
inthis analysis as an option for remediation.
Major ARARs include:
1) Pennsylvania's ground water ARAR is that groundwater mustbe
cleaned up to background levels. Halogenated organics do notoccur
naturally in groundwater and therefore background would be"zero or
nondetect. However at this site, based on theinformation available
at the present time, there are believed tobe other sources of
organic contamination in the site vicinitywhich are contributing to
the type and concentration of organiccontaminants identified in the
groundwater. Therefore backgroundmay actually be greater than MCLs
for the site relatedcontaminants. In this case, cleanup of the
plume shall be toMCLs.
2) The Federal and State Safe Drinking Water regulationslists
the primary maximum contaminant levels as applicablerequirements
for public drinking water supplies
3) Handling and disposal of the granular activated carbonunits
would comply with 25 PA Code 261.6(a), Department ofTransportation
(DOT) Rules for Hazardous Materials Transport, andRCRA requirements
for hazardous waste handling, transportation,and disposal of
hazardous waste.
4) Air Emissions from air strippers will be in compliancewith
Federal and State Air Regulations.
3. Long-term Effectiveness and Permanence. Alternative 3, 4 and5
will provide long-term protection of public health fromexposure to
contaminated groundwater by providing an alternativewater supply
and by potentially removing the contaminants ofconcern to
background levels or MCLs which ever is lower.
4. Reduction of Toxicity, Mobility, or Volume through
Treatment.Alternatives 3, 4, and 5 would provide an irreversible
treatmentprocess which would reduce the toxicity of the
contaminatedgroundwater through essentially complete removal (99.8
percent
AR302263
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17
plus) of the volatile chlorinated organic contaminants.
Mobilityof the contaminants would be reduced through the creation
ofhydraulic barriers which would prevent their migration
intouncontaminated areas. Alternative 3 will not effectively
controlcontaminant migration in the shallow aquifer and therefore
wouldnot effectively have the same benefit as the
preferredalternative. The preferred alternative would provide
thegreatest degree of hydraulic control and would effect a
largereduction in the volume of contaminated media by
potentiallycleaning the groundwater to background or MCLs (which
ever islower). Spent carbon from the vapor phase granular
activatedcarbon for the air emission control on the air strippers
will bedisposed of in an approved facility or regenerated on
Site.
5. Short-term EffectivenessActions under all alternatives should
be performed such thatthere would be minimal risk to the community
and to workers.This would mean that appropriate health and safety
measures wouldbe practiced during the construction and operation
phases of thealternatives. Alternative 3 & 4 would require a
longer duration'and greater volume of groundwater extracted to
remediate thegroundwater to cleanup goals than the preferred
Alternative 5A.
6. Implementability. Alternative 3, 4, and 5 will require
theapproval of the state and local governments for the
constructionof water lines within existing road right-of-ways.
Alternatives3, 4 and 5 involve the installation of additional
groundwaterrecovery well(s) a groundwater collection system/piping
system, aholding tank, and activated carbon units. However,
Alternative 5is more complex since cooperation of another property
owner forthe RW-2 well will be required. The treatment process
forAlternative 3, 4, 5 are the same, are well demonstrated and
arereadily implementable.
7. Costs. The estimated 30 year present worth cost of
thepreferred alternative, Alternative 5 (Option A) is
$5,271,700.The highest estimated cost is Alternative 5 (Option B)
at$6,243,400. Alternative 4 (Option A) is $3,346,400; Alternative4
(Option B) is $4,236,000. Alternative 3 (Option A) is$3,141,000;
Alternative 3 (Option B) is $3,800,400.
8. state Acceptance. PADER has assisted EPA in the review of|
reports and Site evaluations. The State has reviewed and!
tentatively agrees with the proposed remedy and is awaiting pubicj
comment before final concurrence.I
I 9. Community Acceptance. Community acceptance of the
preferred|alternative will be evaluated after the public comment
periodends and will be described in the Record of Decision.
| In summary, the preferred alternative is believed to
-
18
the best balance of trade-offs among the five
alternativesevaluated with respect to the nine criteria above.
Based on theinformation available at this time, EPA believes the
preferredalternative would protect human health and the
environment, wouldcomply with ARARs and be cost-effective. In
addition, permanentdisposal options would be utilized to the
maximum extentpracticable.
PUBLIC PARTICIPATION
EPA solicits input from the community on the cleanup
methodproposed for each Superfund response action. EPA has set
apublic comment period from July 21, 1992 to August 20, 1992,
toencourage public participation in the response process.
Thecomment period includes a public meeting at 7:00 P.M., on
August6, 1992, during which EPA will present the proposed
alternativeaction, answer questions, and accept oral and written
comments.The meeting will be held at the following location:
Lower Providenc Township Meeting Room100 Parklane
DriveEagleville, PA
Comments will be summarized and responses to significant
commentsprovided in the Responsiveness Summary section of the
Record OfDecision. Once the ROD is issued, EPA or potentially
responsibleparties can begin Remedial Design activities at the
Site.
To send written comments or obtain further
information,contact:
Ruth Rzepski, Remedial Project ManagerUS EPA Region III,
(3HW21)841 Chestnut BuildingPhiladelphia, PA 19107(215)
597-3216
orMervin Harris, Community Relations CoordinatorUS EPA Region
III, (3EA21)841 Chestnut BuildingPhiladelphia, PA 19107(215)
597-2129
All comments must be submitted to one of the above people
andpostmarked no later than August 20, 1992.
AR302265
-
19
Glossary of Evaluation Criteria
Overall Protection of Human Health and the Environment;
addresseswhether the remedy provides adequate protection to human
healthand the environment and describes how risks posed through
eachexposure pathway are eliminated, reduced or controlled
throughtreatment, engineering controls, or institutional
controls.
Compliance with ARARs; addresses whether a remedy will meet
allof the applicable or relevant and appropriate
requirements(ARARs) of Federal and State environmental laws and/or
justifiesa waiver
Long-term Effectiveness and Permanence; refers to the
expectedresidual risk and the ability of a remedy to maintain
reliableprotection of human health and the environment over time,
onceclean-up goals have been met.
Reduction of Toxicity. Mobility, or Volume through
Treatment;refers to the anticipated performance of the
treatmenttechnologies a remedy may employ.
Short-term Effectiveness addresses the period of time needed
toachieve protection and any adverse impacts on human health andthe
environment that may be posed during the construction
andimplementation period, until clean-up goals are achieved.
Implementabi1ity is the technical and administrative
feasibilityj of a remedy, including the availability of materials
and servicesneeded to implement a particular option.
Cost includes estimated capital, operation & maintenance
(O&M),and net present worth costs.
State/Support Agency Acceptance indicates whether, based on
itsreview of the site information and Proposed Plan, the
Stateconcurs with, opposes, or has no comment on the
preferredalternative.
Community Acceptance; will be assessed in the Record of
Decision(ROD)following a review of the public comments received on
theAdministrative Record and the Proposed Plan.
AR302266
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