EPA Superfund Record of Decision: Davis Park Road TCE EPA ID: NCD986175644 OU 01 Gastonia NC 09/29/1998

                                    EPA/ROD/R04-98/055
                                    1998
EPA Superfund
     Record of Decision:
     DAVIS PARK ROAD TCE
     EPA ID: NCD986175644
     OU01
     GASTONIA, NC
     09/29/1998

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EPA 541-R98-055

                                                        RECORD  OF  DECISION

                                                  REMEDIAL ALTERNATIVE  SELECTION
                                                    DAVIS  PARK ROAD TCE  SITE
                                                    GASTONIA,  GASTON COUNTY
                                                          NORTH CAROLINA
 
                                                U.S. ENVIRONMENTAL PROTECTION AGENCY
                                                              REGION 4
                                                         ATLANTA,  GEORGIA
                                                          SEPTEMBER,  1998

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DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION

Davis Park Road TCE Site
Gastonia, Gaston County, North Carolina

STATEMENT OF BASIS AND PURPOSE

    This decision document presents the selected remedial action for the Davis Park Road TCE
Site in Gastonia, Gaston County, North Carolina, chosen in accordance with the Comprehensive
Environmental Response, Compensation and Liability Act of 1980  (CERCIA),  as amended by the
Superfund Amendments and Reauthorization Act of 1986  (SARA)  and, to the extent practicable, the
National Contingency Plan  (NCP). This decision is based on the administrative record file for
this Site.

    The State of North Carolina 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, may present an imminent
and substantial endangerment to public health, welfare, or the environment.

DESCRIPTION OF THE SELECTED REMEDY

    This remedy addressees the principle threat posed by the Site. The major threat is the
contaminated groundwater emanating from beneath the Site.

    The major components of the selected groundwater remedy include:

       •      Reduction of Groundwater Exposure; connection  of homes,  churches,  and businesses in
              the Davis Park Road Site area to the City of Gastonia public water supply;

       •      Optional wellhead treatment for affected private wells;

       •      Natural attenuation to restore the contaminated aguifer to  the lower of either the
              Maximum Contaminant Levels (MCLs)  or North Carolina Part 2L Drinking Water
              Reguirements. The primary attenuation processes occurring at the Davis Park Road TCE
              Site are dispersion and intrinsic biodegradation;

       •      Continued analytical monitoring for contaminants in groundwater,  and

       •      Develop contingency plans to respond to differences in the  actual performance of the
              remedy and actual site conditions, as compared to the expected performance of the
              remedy and expected site conditions.  Additional information will be collected during
              the first year of the Remedial Design effort in order to support the predicted
              dispersion and intrinsic biodegradation rates  for the contaminated groundwater.  The
              contingency plans may include the implementation of institutional controls,
              modifications to the monitoring program,  and implementation of the contingency
              remedy,  if necessary.

The contingency remedy includes:

       •      Reduction of Groundwater Exposure; connection  of homes,  churches,  and businesses in
              the Davis Park Road Site area to the City of Gastonia public water supply;

       •      Optional wellhead treatment for affected private wells;

       •      Groundwater pump and treat using a minimum of  three extraction wells with treatment
              of contaminated groundwater at the ground surface using activated carbon to remove
              VOCs.

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       •       Continued analytical monitoring for contaminants  in groundwater.

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, and is cost-effective. This remedy utilizes permanent solutions and alternative
treatment technology to the maximum extent practicable,  and satisfies the statutory preference
for remedies that employ treatment that reduces toxicity, mobility, or volume as a principal
element.  This statutory preference for treatment is satisfied through intrinsic biodegradation
for the selected remedy, and through groundwater extraction and treatment for the contingency
remedy.

    Since this remedy may 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.

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TABIiE OF CONTENTS

SECTION PAGE NO.

1.0 SITE NAME, LOCATION AND DESCRIPTION 1-1
A. Introduction 1-1
B. Site Description 1-1
C. Demography 1-3
D. Surrounding Land/Water Use 1-3
E. Topography 1-3
F. Climate 1-4
G. Geology 1-4
H. Hydrogeology 1-5

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
A. Site History
B. Previous Investigations
C. Site Regulatory Actions

3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 3-1

4.0 SCOPE AND ROLE OR RESPONSE ACTION WITHIN SITE STRATEGY 4-1

5.0 SUMMARY OF SITE CHARACTERISTICS 5-1
A. Source Area/Soil Investigation 5-1
B. Surface Water and Sediment Investigation 5-5
C. Residential Well Survey 5-5
D. Private Well Sampling 5-5
E. Shallow Groundwater Investigation 5-5
F. Bedrock Groundwater Investigation 5-10
G. Bedrock Fracture Analysis 5-10
H. Natural Attenuation Evaluation 5-17
I. Ecological Evaluation 5-17

6.0 SUMMARY OF SITE RISKS 6-1
A. Chemicals of Potential Concern 6-1
B. Exposure Assessment 6-2
C. Toxicity Assessment 6-2
D. Risk Characterization 6-7
E. Uncertainties 6-10
F. Conclusions 6-10

7.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS) 7-1

A. Chemical Specific ARARs 7-1
B. Location Specific ARARs 7-3
C. Action Specific ARARs 7-3
D. Media of Concern 7-3

8.0 REMEDIAL ACTION OBJECTIVES 8-1

9.0 DESCRIPTION OF ALTERNATIVES 9-1
A. Alternative 1 - No Action 9-1
B. Alternative 2 - Institutional Controls 9-2
C. Alternative 3 - Reduction of Groundwater Exposure and
Monitored Natural Attenuation
D. Alternative 4 - Reduction of Groundwater Exposure and
Groundwater Treatment
E. Alternative 5- Reduction of Groundwater Exposure and
Groundwater Pump and Treat

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10.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES                                        10-1
        A. Alternative 1 - No Action                                                        10-2
        B. Alternative 2 - Institutional Controls                                           10-4
        C. Alternative 3 - Reduction of Groundwater Exposure and
                             Monitored Natural Attenuation                                  10-5
        D. Alternative 4 - Reduction of Groundwater Exposure and
                             Groundwater Treatment                                          10-8
        E. Alternative 5- Reduction of Groundwater Exposure and
                             Groundwater Pump and Treat                                     10-9
        F. Comparative Analysis of Alternatives                                            10-11

11.0 THE SELECTED REMEDY                                                                   11-1

12.0 DOCUMENTATION OF SIGNIFICANT CHANGE                                                   12-1

APPENDIX A - RESPONSIVENESS SUMMARY
APPENDIX B - JULY 28, 1998 PUBLIC MEETING TRANSCRIPT
APPENDIX C - STATE CONCURRENCE

FIGURES

 1-1  Site Location Map                                                                      1-2
 2-1  Historical TCE detections in Private Wells                                             2-3
 5-1  May 1996 Source Soil Sampling Locations                                                5-2
 5-2  October 1996 Source Soil Sampling Locations                                            5-3
 5-3  1997/1998 Source Soil Sampling Locations                                               5-4
 5-4  SW/Sediment Sampling Locations                                                         5-6
 5-5  Residential Well Survey                                                                5-7
 5-6  1996 Groundwater Well Sampling Locations                                               5-8
 5-7  1997/1998 Monitoring Well Locations                                                    5-9
 5-8  TCE Concentration Isopleth                                                            5-11
 5-9  PCE Concentration Isopleth                                                            5-12

TABLES

 5-1  Chemicals Detected in Soil and Groundwater                                            5-13
 6-1  Exposure Point Concentrations in GW                                                   6-3
 6-2  Exposure Point Concentrations in Soil                                                 6-4
 6-3  Carcinogenic Toxicity Assessment                                                      6-5
 6-4  Noncarcinogenic Toxicity Assessment                                                   6-6
 6-5  Cancer and Noncancer Risks                                                            6-8
 6-6  Uncertainties in the Risk Assessment                                                  6-11
 7-1  Chemical-specific ARARs                                                               7-2
 7-2  Location-specific ARARs                                                               7-4
 7-3  Action-specific ARARs                                                                 7-5
 8-1  Remediation Goals for Groundwater                                                     8-1
 9-1  Remedial Action Alternatives for Groundwater                                          9-1
 10-1 Comparative Analysis for Groundwater                                                 10-12
 11-1 Capital Costs for Selected Remedy                                                    11-2
 11-2 Remedial Action Operation Costs                                                      11-3

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1.0 SITE NAME, LOCATION, AND DESCRIPTION

A.    Introduction

      The Davis Park Road TCE Site (hereinafter referred to as the "Site" or the "Davis Park
Road Site") is located in a mixed residential and small business neighborhood along Davis Park
Road, south of Hudson Boulevard and north of Blackwood Creek in the southwestern portion of
Gastonia, North Carolina  (Figure 1-1).  The Site also includes the soil behind the building that
is currently occupied by the Davis Park Auto Repair shop at 2307 Davis Park Road, and a plume of
contaminated groundwater that was believed to emanate from this property. The Cedar Oak Park
Subdivision located on the east side of Davis Park Road, within the confines of Cedar Oak
Circle, as well as areas along the western side of Davis Park Road are also included in the Site
area.

B.    Site Description

      During the Remedial Investigation ("RI")  the soil behind the building located at 2307
Davis Park Road and a plume of contaminated groundwater believed to emanate from this property
were investigated. The Davis Park Road Site is located at latitude 355 13' 56" N and longitude
815 13'08" W. The Site, situated on approximately 20 acres, includes private businesses and
residential homes. The topography of the area is slightly sloped to the west toward Crowders
Creek and to the east and south towards Blackwood Creek. Both creeks are receiving streams for
groundwater in the area.

      The potential source of the contaminated groundwater is an area of formerly contaminated
soil located behind the Davis Park Auto Repair Shop at 2307 Davis Park Road, in the vicinity of
a drain line that exited the service bay in the facility. Numerous service stations and repair
shops have operated at the 2307 Davis Park Road location beginning in 1956. The results of soil
sampling conducted by the North Carolina Department of Environment and Natural Resources
("NCDENR") confirmed that at some time during the operation of the facility as a service station
or transmission and auto repair facility,  tetrachloroethene ("PCE")  and possibly trichloroethene
("TCE") were released through a drain line installed in the service bay area of the building.
According to NCDENR, these contaminants were detected in the soil around the drain pipe that
exited the facility. However, no soil contamination was detected during sampling conducted
during the RI.

      PCE and TCE have been detected in groundwater sampled from a community well and several
private wells within the area of the Site at levels exceeding Federal and State drinking water
standards. Additionally, 1,2-dichloroethene ("1,2-DCE"), a breakdown product of PCE and TCE, has
been detected in both community and private wells in the area.

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valleys. In general, the topographic changes are gradual,  except for occasional steep-sided
steam valleys. The average elevation in Gastonia is 825 feet above sea level.

     The elevation at the Davis Park Road Site ranges from 675 feet above sea level at Blackwood
Creek to 770 feet above sea level at the Davis Park Road Auto Repair facility at 2307 Davis Park
Road. The Davis Park Auto Repair shop is located approximately 2,550 feet north of Blackwood
Creek. The elevation declines gradually to the southeast,  south, southwest,  and west of this
location.

     Gaston County is drained by various streams and creeks that flow south,  southeast, and east
towards Lake Wylie, Crowders Creek is a major drainage area for the southern portion of the City
of Gastonia. Crowders Creek flows south southeast into South Carolina, and approximately 15
miles downstream from that point into Lake Wylie.

     Surface runoff from the Davis Park Road Site flows overland into ditches and/or culverts on
the edges of the various roads that cross the Site or into small streams. Overland flow travels
either south southeast towards Blackwood Creek (a tributary to Crowders Creek)  or west southwest
into smaller, unnamed streams and eventually into Crowders Creek.

     The suspected source area at 2307 Davis Park Road is bounded by Davis Park Road to the
east, and by private residences to the north and south. The western portion of the property is
bounded by vacant lots. The area surrounding the building is paved on the eastern and southern
portions. The western portion of the site is covered by areas of grass, weeds,  and trees
intermixed with discarded eguipment from the operations at the facility. The northern portion of
the property is covered by grass and trees. The distance from the building to the closest
residential property north is approximately fifteen feet

F.   Climate

    The climate is moderate with approximately one half of the winter days falling below
freezing. Little snow falls and the occasional heavy snow usually melts within one or two days.
The average freeze-free period is 216 days. The summers are warm with temperatures into the 905F
range.

G.   Geology

     According to the 1988 Geologic Map of the Charlotte 15 X 25 Quadrangle,  the Davis Park
Road Site is directly underlain by the Pennsylvanian Age High Shoals Granite Formation. This
formation is described as being very light gray,  course-grained, porphyritic, well foliated,
commonly gneissoid biotite granite. This formation has been zircon dated at 317 million years
old and may be cogenitic with the Churchland Pluton, which lies to the northeast of the Site and
underlies the northern portion of the City of Gastonia.

     The High Shoals Granite and Churchland Plutonic Suite are labeled as the High Shoals
Pluton. The High Shoals Pluton is a linear shaped body of granite material that trends
northeast-southwest. The High Shoals Pluton is surrounded by guartz sericite schists and
metavolcanic rocks of the Battleground Formation. In the Gastonia area, the pluton is bordered
on the west by the South Fork Anitform and on the east by the Boogertown Shear Zone. Flow
foliation in these rocks is either vertical or is greater on average than 755,  and typically
trends northeast to southwest. The High Shoals Pluton is considered to have originated after a
regional metamorphic phase in the Late Paleozoic Age.

     Geology underlying the Davis Park Road Site is described based on data generated from
monitor well installation and soil borings. As the rock types underlying the Site become
weathered through physical, chemical, and biological processes, soil profiles develop that are
characteristic of the original rock. For example, the granite rock tends to weather to a silty
clay rich loam or a rich sand material, with depth. The sand originates from guartz present in
the original parent rock, and can range in size from fine to coarse-grained.  The clay is derived
from weathering of feldspathic minerals in the parent rock. Clay-rich soil in which parent rock
structures are preserved is referred to as saprolite.

     Bedrock underlying the Site is fracture as a result of regional metamorphic activity. In
some cases, remnant fractures are represented by iron staining along a fracture plane. The iron
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staining, which is also referred to as the mineral limonite, is a result of groundwater leaching
iron from the surrounding material. As the groundwater travels along a fracture plane,  the iron
is redeposited along the plane. In other cases, the fracture planes have been "resealed" by
guartz.  As the rock weathers, these guartz fillings are retained in the soil indicating that
fractures existed in the rock. Fracture planes were also identified as zones of weak to
incompetent rock that were not resistant to the cutting action of the drill bit. These fracture
zones, or secondary porosity features, were typically saturated.

     During the field activities,  the geology varied across the Site; however,  a common pattern
was observed. From top to bottom,  the materials consist of a saproilite layer,  a partially
weathered rock zone, and the underlying fractured crystalline bedrock. The saprolite is
clay-rich, residual material derived from in-place weathering of bedrock. Typically, the
saprolite is silty clay near the surface. With increasing depth, the amount of mica, silt, and
fine-grained sand and gravel tend to increase. Remnant fracture planes with guartz infilling
appear in this layer. The saprolite zone is thickest (approximately 80 feet) along the ridge
crest along the northern edge of the Site, thinning towards the lower elevations or stream
valleys to approximately 20 feet in thickness.

     Underlying the saprolite is a partially weathered rock layer derived from the weathering of
bedrock that ranges in thickness from approximately 5 to 25 feet. This layer is composed of
saprolite and fragments of weathered bedrock. Particle sizes range from silts and clays to large
boulders of unweathered bedrock. The weathering occurs in bedrock zones less resistant to
physical and chemical degradation  (i.e., fault zones, stress relief fractures,  and mineralogic
zones).

     The predominant rock type, based on rock samples obtained during bedrock monitoring well
drilling is a metamorphosed brownish-gray to light gray, guartz bioti granite or granitic
gneiss.  The bedrock is fractured and these fractures contain guartz deposits that remain
unweathered in the  saprolite.

H.   Hydrogeology

     Metamorphosed and fractured guartz-sericite schist, metavolcanic rocks, and granite rocks
in varying proportions and thicknesses comprise the aguifer system represented by the water
bearing units that underlie the Davis Park Road Site and surrounding areas. Geologic structures
that produce high-yielding wells include contact zones of multilayered rock units, zones of
fracture concentration, and stress-relief fracture zones. According to data collected by LeGrand
and Mundorff (1952), wells in Gaston County that are set within granite have an average depth of
165 feet and an average yield of 18 gallons per minute. Within the Davis Park Road area, data
collected by LeGrand and Mundorff indicate that well depths range from 80 to over 250 feet and
that well yields range from 2.5 to 116 gallons per minute. The aguifer system underlying the
Site generally consists of the saprolite/partially weathered rock aguifer and the underlying
bedrock aguifer; however, interconnection between these units is likely which would influence
contaminant transport.

     In the Site area, the top of the water table is typically found in the saprolite aguifer
and generally mimics the overlying land surface. The saprolite and partially weathered rock
comprise an overburden aguifer, which has a thickness that ranges from approximately 10 to 80
feet below ground surface. The depth to water across the area ranges from approximately 3 to 45
feet below ground surface. The greatest depth to water is found along the ridgeline on the
northeast portion of the Site, which is also the location of the Davis Park Road Auto Repair
Shop. A fractured bedrock aguifer underlies the overburden, and the fractures generally decrease
with depth.

     Using groundwater elevations collected in January and February 1998, and potentiometric
maps drawn from these groundwater elevations, groundwater within the overburden and bedrock
aguifer generally flows to the southeast to south across the site. Based upon the potentiometric
contours, the Davis Park Auto Repair property appears to be located within a localized
groundwater high area, with potentiometric contours emanating in a semi-circular pattern from
this area.

     Water level elevations and local topographic contour maps for monitor wells MW-1D, MW-2S,
MW-2D, and MW-5S suggest that groundwater discharges form the overburden and possibly the
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bedrock aquifers into Blackwood Creek along the eastern and southeastern edge of the Site;
however, fractures present in the partially weathered rock and bedrock may affect the direction
of groundwater flow, and relict fractures present in the saprolite may also control groundwater
flow directions. According to Earned (1989), while working in the Piedmont Province of Guilford
and Mecklenburg Counties of North Carolina, most of the natural flow in the bedrock system is
probably confined to the upper 30 feet of bedrock where fractures are concentrated, and the
overlying partially weathered rock zone, which appears to have the highest hydraulic
conductivity of any part of the hydrogeologic system.

2.0  SITE HISTORY AND ENFORCEMENT ACTIVITIES

  A.  Site History

      The building at 2307 Davis Park Road has been owned by Carl Bell (now deceased)  and
Douglas Bell of Gastonia and Charlotte, respectively, since 1960. Carl Bell leased the property
to Acme Petroleum and Fuel Company ("ACME") of Gastonia in 1966. ACME held this lease until
1981. During the lease period, the property was subleased to various service stations and repair
shops. Recently (1996 or early 1997), the name of the business in the building at 2307 Davis
Park Road was changed to Davis Park Auto Repair. On February 18, 1991, two underground storage
tanks were removed from the property. At the time of removal one tank was reported to have 5-7
inches of product and the other 3 to 4 inches of product. Upon removal of the tanks, soils in
the vicinity of the tanks were tested for contamination. Results showed no contamination present
from the soils around the tanks.

      The investigation of possible groundwater contamination began on March 31, 1990, when a
groundwater sample was collected by Gaston County Environmental Health Department
representatives from a community supply well within the Cedar Oak Park subdivision as part of a
routine sampling procedure. Analysis of the sample revealed concentration of TCE (34.9 parts per
billion), and PCE (23.7 parts per billion). During April of that year, Gaston County
Environmental Health Department officials collected samples from three nearby private wells. The
sampling revealed the groundwater was contaminated with TCE, with the highest detected level
(101.4 parts per billion) in a sample collected from the private well located at 2419 Davis Park
Road, 200 feet south of the building at 2307 Davis Park Road.

  B.  Previous Investigations

      In 1991 the NCDENR conducted a Site Investigation of the property at 2307 Davis Park Road.
This investigation reported that TCE as high as 700 parts per billion ("ppb") and PCE as high as
3,000 ppb was present in soil samples taken from near a drain pipe which exits the rear of the
building at 2307 Davis Park Road. At the request of EPA, NCDENR prepared a Site Inspection
Addendum report to the Site Investigation.  This investigation confirmed the presence of PCE and
TCE as well as 1,2-DCE in soil samples taken from the vicinity of the drain line. However, in a
follow-up Expanded Site Investigation in 1994, conducted by NCDENR, the concentration of TCE in
soil had dropped to 38 ppb and the concentration of 1,2-DCE, to between 4 and 20 ppb.  No PCE was
detected in the soil samples, however,  some additional Volatile Organic Compounds  ("VOCs"),
thought to be petroleum-type compounds, were detected in soils at low levels.

      During the Site Inspection Addendum investigation, NCDENR summarized sample data from
22 private wells in the vicinity of the Site. The sampling was conducted by State and Gaston
County Environmental Health officials from May 1990 to August 1992. Fourteen of the samples
contained a detectable amount of TCE or PCE or both. The 1994 Expended Site Investigation
confirmed contamination in five of the previously sampled wells. Figure 2-1 presents the
locations of the private wells which showed detectable levels of TCE contamination from
1990-1995.

  C.  Site Regulatory Actions

      This Site was proposed for inclusion on the National Priorities List in July of 1998.

      On March 19, 1996, a General and Special Notice letter for Remedial
Investigation/Feasibility Study was sent to one potentially responsible party. After
negotiations, the EPA initiated and conducted the RI/FS.
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3.0   HIGHLIGHTS OF COMMUNITY PARTICIPATION

      Pursuant to CERCLA Sections 113(k) (2) (B) (i-v) and 117, the RI/FS Report and the Proposed
Plan for the Site were released to the public for comment on July 23, 1998. These documents were
made available to the public in the administrative record located in an information repository
maintained at the EPA Docket Room in Region IV and at the Gaston County Public Library in
Gastonia, North Carolina.

      The notice of the availability of these documents was published in the Charlotte Observer
and Gaston Gazette on July 25, 26 and 27, 1998. A pubic comment period on the documents was held
from July 27, 1998 to August 26, 1998. A copy of the notice was mailed to the site mailing list
which contains names of community members and interested parties. In addition, a public meeting
was held on July 28, 1998. At this meeting, representatives from EPA answered guestions about
the Site and the remedial alternatives under consideration. Meetings with city and county
officials were also held.

      Other community relations activities included:

       •      Established an information repository

       •      Conducted community interviews

       •      Prepared an extensive mailing list

       •      Developed a community relations  plan

       •      Issuance of a fact sheet on the  RI/FS process in April,  1996

       •      Issuance of a fact sheet on the  proposed plan in July,  1998

       •      Notice of availability of information in repository and public meetings on July 25,
              26 and 27,  1998

       •      Informed citizens of the Technical Assistance Grant and Community Advisory Group
              program (literature placed in repository).

4.0   SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY

      As with many Superfund sites, the Davis Park Road Site is very complex. However, all
aspects of the cleanup will be addressed concurrently and the Site has not been divided into
phases or "operable units."

      This ROD will present a final remedial action for the entire Site.

5.0 SUMMARY OF SITE CHARACTERISTICS

        The Remedial Investigation  ("RI") was conducted in three phases beginning in May of 1996
and ending in the Spring of 1998. During the RI, surface and subsurface soil, sediment and
surface water, and groundwater were sampled to determine the nature and extent of contamination.
For a more detailed summary, refer to the RI Report.

        The main contaminants at the Site are tetrachloroethene  ("PCE") and trichloroethene
("TCE"). The following discussion highlights these constituents as well as any chemical
constituents which exceed the National Primary Drinking Water Regulations  ("NPDWR") Maximum
Contaminant Levels  ("MCLs"), the National Secondary Drinking Water Regulations  ("SMCLs"),
Federal Ambient Water Quality Criteria  ("AWQC"), EPA Region 3 Risk-Based Concentrations  (Smith,
1996) and the North Carolina Groundwater Classification and Standards-Groundwater Quality
Standards of the North Carolina Administrative Code (ISA NCAC 2L 0202(c)), and North Carolina
Water Quality Standards applicable to Surface Waters  (ISA NCAC 2B 0200).

    A. Source Area/Soil Investigation
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       Extensive soil sampling was conducted during the RI to try to determine if a continuing
source of contamination exists in soils behind the 2307 Davis Park Road building, the current
location of the Davis Park Road Auto Repair shop. During the May 1996 field investigation,  a
total of 15 soil samples (six surface and nine subsurface) were collected from six locations in
the area immediately surrounding the Davis Park Auto Repair Shop. Sample # 6-SLA was a grab
sample taken through the floor of the building.  (Figure 5-1). The samples were analyzed for
volatile and semi-volatile organic compounds,  pesticides,  PCBs and metals. Two of the samples
contained detectable levels of the organic compounds toluene, ethyl benzene,  xylenes,
trimethylbenzene, benzene isomers and the presumptive evidence of petroleum product.
Semi-volatile organic compounds indicating petroleum product were detected in 3 soil samples.
Two soil samples contained detectable levels of PCB-1242 and PCB-1254 and the pesticides
toxaphene and dieldrin. Metals were detected in all soil samples, at levels consistent with the
geology in the area of the Site.

    In October of 1996, nine soil samples were collected from four to six inches below land
surface at Slocations on the property of 2307 Davis Park Road (Figure 5-2). All of the samples
were analyzed in the field for VOC content. Only one sample contained an estimated value of
bromoform. No other VOC was detected in the other soil samples.

    During the last phase of the field investigation conducted from late fall 1997 to spring of
1998, an additional 7 soil borings were advanced to determine the possible extent of soil
contamination at depth on the property at 2307 Davis Park Road (Figure 5-3).  The soil borings
were advanced using both a geoprobe and a hollow-stem auger drill rig, and were terminated at
auger refusal. A total of 19 samples were collected and sent for VOC analysis. Of the samples
submitted, only one compound (Benzene)  was detected in one sample.





    One soil samples from each of the borehole installations for four top-of-bedrock monitor
wells were submitted for laboratory analysis.  The samples were analyzed for VOC content. Of the
samples submitted,  there were no detections of VOC compounds.

    B. Surface Water and Sediment Investigation

       Surface water and sediment samples were collected during the 1996 field investigation and
again during the 1997/1998 investigation from locations on both Crowders Creek and Blackwood
Creek (Figure 5-4). All samples were analyzed for VOCs. No VOCs were detected in any of the
surface water samples. During the 1996 investigation, one sediment sample, collected from the
Blackwood Creek at the far eastern edge of the Site  (location 2-SD) contained low levels of two
trimethylbenzene isomers and the presumptive evidence of petroleum product. No VOCs were
detected in sediment samples collected in 1997/1998.

    C. Residential Well Survey

       A residential well survey was conducted in November 1995,  and supplemented with data
taken in February,  1998. The results of this survey are shown on Figure 5-5.  Groundwater is
considered as a Class IIA Aguifer since it is currently used as a drinking water source (USEPA,
1988, Guidance on Remedial Actions for Contaminated Groundwater on Superfund Sites). The State
of North Carolina classifies the aguifer as a GA aguifer since it is a present drinking water
source and contains naturally occurring chloride concentrations less than 250 milligrams per
liter (North Carolina Administrative - Code, Title 15, Subchapter 213.0201).

    D. Private Well Sampling

       During the May 1996 field sampling twenty nine (29) residential wells were sampled in the
vicinity of the Site to determine the water guality of the residences drinking water. TCE was
detected in five residential wells above the State Drinking Water Standard. PCE was detected in
four wells. The only other VOC detected above State or Federal Drinking Water Standards was
Chloroform, which was detected in one well. Four of the 29 well samples were also analyzed for
semi-volatile organic compounds, pesticides/PCBs, and metals.
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    E. Shallow Groundwater Investigation

       In 1996, EPA installed three temporary monitoring wells and sampled two existing
monitoring wells all located on the property at 2307 Davis Park Road. In addition, one temporary
well was installed southeast of the property, near Blackwood Creek. All wells were set within
the shallow  (overburden) aguifer. During the 1997/1998 phase of the RI, EPA installed 5
additional shallow monitoring wells throughout the Davis Park Road Site study area, and
converted three former residential wells of known depth to permanent monitoring wells with the
consent of the residents. Figure 5-6 shows the locations of the 1996 shallow monitoring wells
and Figure 5-7 shows the location of the 1997/1998 monitoring wells.






       EPA collected groundwater samples from shallow monitoring wells in 1996 (all located on
the 2307 Davis Park Road Property + one near Blackwood Creek)  and in January and February 1998
(one well on the property and 8 new wells).  The wells were sampled to determine if contamination
was present in the shallow (overburden) aguifer.

       Of the VOC contaminants detected, only methyl-tert-butyl ether  (MTBE)  was detected at
levels exceeding the State Drinking Water Standard.

    F. Bedrock Groundwater Investigation

       Four new bedrock monitoring wells were installed during the 1997/1998 investigation. In
addition, EPA converted two former residential wells set within the bedrock aguifer to permanent
monitoring wells (Figure 5-7). During January and February, 1998,  EPA sampled the 6 new
monitoring wells, one existing well located at the 2307 Davis Park Road property, and three
residential wells known to be set within the bedrock aguifer.  All samples were analyzed for
VOCs. Of the compounds detected, only TCE and PCE were detected above the State or Federal
Drinking Water Standards. Other VOCs detected include MTBE and Acetone. Groundwater plume
Isopleth maps were generated for TCE and PCE plumes located in the Bedrock Aguifer and are
presented as Figures 5-8 and 5-9.

       Table 5-1 shows a summary of the contaminants detected in soil and groundwater at the
Site.

    G. Bedrock Fracture Analysis

       During the 1997/1998 phase of the RI, EPA conducted a Bedrock Fracture Trace Study and
downhole geophysical logging of the newly installed bedrock wells. The fracture trace study was
conducted to identify zones of high fracture concentration in the bedrock, which typically
indicate increased groundwater flow along their length. The data was also used to establish the
locations of the bedrock monitoring wells at the Site. The azimuths of the fracture traces were
plotted on a rose diagram to assess the preferred orientations for fractures traces in the area
of the Site. The primary trends for fractures in the bedrock system in the Site area lie in a
south to southeasterly direction, generally from the property at 2307 Davis Park Road toward
Blackwood Creek.

       During the downhole geophysically logging of the bedrock monitoring wells, fracture zones
within the bedrock were identified based on prominent anomalies. Hydraulically active fractures
were identified. These fractures contribute water to the water column under static well
conditions, and these hydraulically active fractures may potentially act as contaminant
transport pathways. Low and High angle fractures were identified within each borehole. The high
angle, or steep fractures generally dipped in an easterly direction, toward Backwood Creek. The
majority of potential water-producing zones occurred in the low, or flat dipping fractures. Two
potential water producing fracture zones were identified. Based on the detection of contaminants
during the groundwater sampling activities,  the correlation of fracture zones between select
monitor wells, and the number of water-bearing shallow dipping structures and steeply dipping
fractures primarily to the east, the spread of contamination toward Blackwood Creek, within the
bedrock aguifer, may be attributed to the interconnection of bedrock fractures.
-------
Table 5-1 Chemicals Detected in Groundwater

                              Residential

       Chemical
Volatiles

Acetone
Bromodicloromethane
Butene
Carbon disulfide
Chiorodibromomethane
Chloroform
1,1-Dichloroethane
1,1-Dichloroethene
Cis-1,2-Dichloroethene
Methyl-tert-butyl ether
Propene
Tetrachloroethene
Toluene
Trichloroethene
1,1,1-Trichloroethane

Pesticides/PCBs

gamma-Chlordane
Overburden
                                          Bedrock
Frequency of
Detection


--
1/31
--
4/31
1/31
1/31
2/31
2/31
2/31
--
—
6/31
—
9/31
1/31

1/4
Range of
Detected
Concentrations
(ug/L)
--
5.8
--
1.3-2.4
0.58
40
0.52-0.57
0.66-1.6
1.6-1.7
--
—
0.52-10
—
0.92-34
1.2
(ug/L)
0.25
Frequency of
Detection


1/12
—
1/1
1/12
—
—
—
—
—
2/10
1/1
--
1/12
1/12
—

	
Range of Detected
Concentrations

(ug/L)
91
—
9
7
—
—
—
—
—
14-790
20
--
0.6
0.84
—
(ug/L)
	
Frequency of
Detection


1/7
—
--
—
—
—
—
1/7
—
1/7
—
2/7
—
2/7
1/7


Range of De
Concentrat

(ug/L)
83
—
--
—
—
—
—
3.8
—
42
—
6-14
—
17-32
7.8
(ug/L)
	
-------
Table 5-1 (cont.) Chemicals Detected in Groundwater

                              Residential
       Chemical
Inorganics

Aluminum
Barium
Calcium
Copper
Iron
Magnesium
Manganese
Potassium
Sodium
Strontium
Titanium
Vanadium
Zinc
                              Freguency of
                               Detection
   Range of
   Detected
Concentrations

     (ug/L)
Overburden

Freguency of
 Detection
—
4/4
4/4
2/4
2/4
4/4
—
4/4
4/4
4/4
2/4
4/4
—
14-21
6200-11000
3.4-12
14-26
1100-3700
—
1400-2500
8300-10000
130-200
4.2-5.9
4.4-7.3
1/1
1/1
1/1
—
1/1
1/1
1/1
1/1
1/1
1/1
—
1/1
Range of Detected
 Concentrations
                      (ug/L)

                       460
                        81
                       8100

                       170
                       3200
                        24
                       2700
                      16000
                       200
                                                                                         16
 Bedrock

Freguency of
 Detection
                                                                 1/1
                                                                 1/1
                                                                 1/1

                                                                 1/1
                                                                 1/1
                                                                 1/1
                                                                 1/1
                                                                 1/1
                                                                 1/1
                                                                 1/1
Range of Detected
 Concentrations
                                               (ug/L)

                                                 56
                                                 72
                                                7300

                                                 49
                                                2900
                                                 22
                                                2500
                                                16000
                                                180
                                                                                                                                   70
-------
Table 5-1  (cont) Chemicals Detected in Soil

                              0-6"
                                                                     0-16'1
Chemical
Volatiles

Benzene
Bromoform
Ethyl benzene
Toluene
m/p Xylene
o-Xylene

Semi-volatiles

Acenapthene
Dibenzofuran
2-Methylnapthalene
Napthalene
Phenanthrene
Pyrene

Pesticides/PCBs

Dieldrin
Toxaphene
PCB-1242
PCB-1254
                          Frequency of
                            Detection
1/13
             Range of Detected
               Concentrations

                   (mg/kg)
0.0072
                   (mg/kg)
1/6
1/7
(mg/kg)

 0.018


 0.091
                 Frequency of
                   Detection
1/10
1/14
1/14
1/14
1/13
1/13
                                          1/6
                                          1/6
                                          2/6
                                          2/7
                                          2/6
                                          1/6
 1/6
 1/6
 1/9
 1/9
Range of Detected
  Concentrations

      (mg/kg)

       0.012
       0.0072
       0.011
       0.42
       0.035
       0.031

      (mg/kg)

        1.2
         2
      1.9-9.4
      0.66-10
      0.6-0.6
        0.38

      (mg/kg)

       0.018
         10
       0.17
       0.057
-------
Table 5-1 (cont) Chemicals Detected in Soil

                              0-6"
Chemical
Inorganics

Aluminum
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Strontium
Titanium
Vanadium
Yttrium
Zinc
                          Freguency of
                            Detection
Range of Detected
  Concentrations

     (mg/kg)
   0-16"

Freguency of
  Detection
Range of Detected
  Concentrations

     (mg/kg)
6/6
6/6
6/6
1/6
2/6
6/6
6/6
6/6
6/6
6/6
6/6
6/6
6/6
3/6
5/6
6/6
6/6
6/6
6/6
6/6
6/6
20000-40000
4.8-15
72-100
1.1
1.4-3.2
370-28000
9.5-32
4.8-11
18-56
16000-38000
20-630
1900-10000
140-360
0.06-0.13
9.3-27
1600-3400
15-37
630-1000
38-56
5.5-17
50-300
6/6
6/6
6/6
1/6
2/6
6/6
6/6
6/6
6/6
6/6
6/6
6/6
6/6
3/6
5/6
6/6
6/6
6/6
6/6
6/6
6/6
20000-52000
4.7-15
52-110
1.1
1.4-3.2
370-28000
6.4-32
4.8-11
5.7-56
16000-51000
20-630
1800-10000
87-360
0.06-0.13
9.3-27
1600-4500
4-38
600-1600
38-120
5.5-17
37-300
-------



H.  Natural Attenuation Evaluation

    A historical review of TCE and PCE concentrations in groundwater samples collected from
private wells north and south of the property at 2307 Davis Park Road was conducted to determine
if contaminant levels were decreasing with time without active remediation. Sixteen (16)  well
locations were chosen based on availability of data, beginning with sampling conducted in 1990
through the 1997/1998 field investigation. A graphical representation of the data indicates a
decline in contaminant levels, with the exception of the residence furthest south, or closest to
Blackwood Creek Fluctuating levels of PCE and TCE with predominant decreasing trends were
recorded in the residential wells south of the 2307 Davis Park Road property. The contamination
in wells closest to the property, which initially showed the highest detected levels,  had
dropped to below detection limits. Based on the data collected from the RI, the groundwater
contaminant plume appears to be located in the bedrock aguifer only. The contamination from the
suspected source at the 2307 Davis Park Road property appears to be flushing from that point and
has migrated south to southeast through the bedrock aguifer and is discharging to Blackwood
Creek.

    Modeling of the TCE plume was performed using the groundwater model BIOSCREEN. BIOSCREEN is
a screening model that simulates remediation through natural attenuation. The model was designed
to simulate biodegradation by both aerobic and anaerobic reactions. Using available data, the
source zone concentration and source zone half lives were adjusted until the BIOSCREEN output
matched to 1996 and 1998 plume and source geometry. The model was then run for an additional 7
years  (beyond 1996) to determine the likely plume shape and dissolved contaminant concentrations
after those times. The model predicted that the plume will reach a maximum length of 3,400 feet
in four years from the present time (year 2002), and will be below Federal MCLs within 7 years
from the present time. However, the distance from the suspected source at 2307 Davis Park Road
to Blackwood Creek is just 2550 feet.  Blackwood Creek is a receiving stream in this area, and
contamination has been detected in groundwater wells located near the Creek. This information
combined with the BIOSCREEN model results indicates that the groundwater plume has reached its
maximum extent.

I.  Ecological Evaluation

    As a result of extensive development, there are no known critical habitats or federally
listed endangered species in the immediate vicinity of the Site. The Site includes commercial
and residential buildings, paved roads and paved parking areas, and open areas of maintained
vegetation. There are limited areas of woodlands within the immediate Site vicinity, however,
the woodlands are more extensive along the southeastern, southern, and western perimeters of the
Site.

    Soil types in the valley of crowders Creek are almost totally Chewacla loam (CH) or Conagree
loam  (Co), both of which are listed as hydric soils capable of supporting wetlands. However, the
five predominant soil types in the immediate vicinity of the Davis Park Road Site area (Appling
sandy loam. Cecil-Urban land complex,  Helena-Urban land complex, Pacolet sandy loam and Edowee
sandy loam) are not listed as hydric soils. There are no wetlands in the immediate vicinity of
the Site. The areas along Blackwood Creek within the immediate vicinity of the Site are
comprised of "urban" soils and "urban" vegetation. Conseguently, what organisms and their
environments that might have existed are no longer in evidence following the "urbanization" of
Blackwood Creek in this area.

    The Indiana Bat, Bald Eagle, Arctic Peregrine Falcon, and Eastern Cougar are endangered or
threatened species which have been identified in the vicinity of the Site. However, no known
critical habitats are found in the Site vicinity. Several sensitive environments,  several
species of millipedes listed as State endangered, threatened or of special concern, the Bear Oak
(listed as significantly rare), and Crowders Mountain State Park are located in Site vicinity.

6.0 SUMMARY OF SITE RISKS

    The Davis Park Road Site is releasing contaminants into the environment. The Baseline Risk
Assessment Report presents the results of a comprehensive risk assessment that addresses the
-------
potential threats to public health and the environment posed by the Site under current and
future conditions, assuming that no remedial actions take place, and that the surrounding area
will remain a residential community.

    The Baseline Risk Assessment Report consists of the following sections: identification of
chemicals of potential concern; toxicity assessment; human exposure assessment; and risk
characterization. All sections are summarized below.

A.  Chemicals of Potential  (Concern (COPCs)

    Data collected during the RI were reviewed and evaluated to determine the chemicals of
potential concern at the Site which are most likely to pose risks to the public health. These
contaminants were chosen for each environmental media sampled.

    The chemicals of potential concern in groundwater are: bromodichloromethane,
chlorodibromomethane, tetrachloroethene (PCE),  trichloroethene  (TCE),  1,1-dichloroethene,
methyl-tert-butyl ether  (MTBE), and chloroform.

    The chemicals of potential concern in soil are toxaphene, aluminum, arsenic, beryllium,
lead, manganese, vanadium and yttrium.

    Once these chemicals of potential concern were identified, exposure concentrations in each
media were estimated. Exposure point concentrations were calculated for surface soils using the
lesser of the 95 percent upper confidence limit  (UCL) concentration or the maximum detected
value as the reasonable maximum exposure (RME)  point concentration. For evaluation of
groundwater, an alternative approach,  often used to assess potential future exposures from wells
that might be installed in an area of contaminated groundwater, is to select several different
wells from the approximate center of the groundwater plume, and to average these values to
derive an estimate of concentration values which might reasonably be expected under worst-case
conditions. At this Site, the only COPC for the overburden aquifer was methyl-tert-butyl ether
(MTBE).  MTBE was detected in 2 out of 10 shallow wells (CW-1 and CW-2). Therefore wells CW-1 and
CW-2 were selected as the designated "center" of the shallow groundwater plume because they are
located near each other and contain MTBE.  At this Site, some of the highest concentrations of
PCE and TCE in the bedrock aquifer were found in well location CW-5. Therefore, this well was
designated as the "center" of the bedrock groundwater plume. In accordance with Region IV
guidance, the mean concentration (rather than the UCL or maximum concentration) is used in this
case to estimate the exposure point concentration when using the "center of the plume". Not all
COPCs for the bedrock aquifer were detected in the "center plume" well. For these COPCs, maximum
detected concentrations were conservatively used to estimate the exposure point concentration.
Exposure point concentrations are shown for groundwater in Table 6-1 and for soil in Table 6-2.

    B.  Exposure Assessment

    The exposure assessment evaluates and identifies complete pathways of exposure to human
population on or near the Site. Current exposure pathways include exposure through incidental
ingestion of soil; inhalation of fugitive dusts from soils; dermal contact with soils; and
ingestion of water from private wells. Land use assumptions include residential and commercial.

    Future use scenarios consider construction of a water supply well within the groundwater
contaminant plume and ingestion of soil, inhalation of dusts and dermal contact with soils as a
worse-case scenario. Possible exposure pathways for groundwater include exposure to contaminants
of concern from the groundwater plume in drinking water and through inhalation of volatiles
evolved from water through household water use. Further detail and mathematical calculations can
be reviewed in the Baseline Risk Assessment.

C.  Toxicity Assessment

    Under current EPA guidelines, the likelihood of adverse effects occurring in humans from
carcinogens and noncarcinogens are considered separately. These are discussed below. Tables 6-3
and 6-4 summarize the carcinogenic and noncarcinogenic toxicity criteria for the chemicals of
potential concern.

    EPA uses a weight-of-evidence system to classify a chemical's potential to cause cancer in
-------
humans. All regulated chemicals fall into one of the following categories: Class A - Known Human
Carcinogen; Class B - Probable Human Carcinogen; Class C - Possible Human Carcinogen; Class D -
Not classifiable as to human carcinogenicity; and Class E - Evidence of Noncarcinogenicity in
humans.

    Cancer slope factors have been developed by EPA for estimating excess lifetime cancer risks
associated with exposure to potentially carcinogenic chemicals. Slope factors,  which are
expressed in units of kg-day/mg, are multiplied by the estimated intake of a potential
carcinogen, in mg/kg-day, to provide an upper-bound estimate of the excess lifetime cancer risk
associated with exposure at that intake level. The term "upperbound" reflects the conservative
estimate of the risks calculated from the slope factor. Use of this approach makes
underestimation of the actual cancer risk highly unlikely.

    Reference doses (RfDs)  have been developed by EPA for indicating the potential for adverse
health effects from exposure to chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg-day, are estimates of lifetime daily exposure levels for humans,
including sensitive individuals; that are free of any adverse effects.

Estimated intakes of chemicals from environmental media can be compared to the RfD. RfDs
are derived from human epidemiological studies or animal studies to which uncertainty factors
have been applied. These uncertainty factors help ensure that the RfDs will not underestimate
the potential for adverse noncarcinogenic effects to occur.
-------
                                                   Table 6-1
                                Exposure Point Concentrations for Groundwater
                                           Davis Park Road TCE Site
Chemical of
Potential Concern

Bedrock Aquifer
Bromodichloromethane
Chiorodibromomethane
Chloroform
1,1-Dichloroethene
Methyl-tert-butyl ether
Tetrachloroethene
Trichloroethene
Sapralite Aquifer
Methyl-tert-butyl ether
Desiqnated Center Plume     Mean 2
         Wells 1            uq/L
Maximum
(well  ID)
  uq/L
Exposure Point
 Concentration
     (uq/kq)
CW-5
uq/L

5 U
5 U
5 U
5 U
5 U
14
32
CW-5
(Formerly PW-239)
uq/L
1 U
1 U
1 U
3.8
NA
10
32

1.5
1.5
1.5
3.15
5
12
32

5.8 (54-PW)
0.058 (54-PW)
40 54-PW)
3.8 CW-5)
42 (MW-3D)
14 (CW-5)
34 (PW-3)

5.8
0.058
40
3.15
42
12
32
 14
               790
                             402
                                         790 (CW-2)
                                                                 402
Notes:
NA-not analyzed
1 Exposure point concentrations for qroundwater are based on data from wells located in the
center of the plume. If the data from the center plume wells were nondetect, then the maximum
detected concentration was selected as the EPC.
Note, well CW-5 was sampled on 5/1/96 and 1/14/98.
2 Data that was nondetect  (ie: IU)  were assumed to be present at 1/2 the detection limit. As a
result, data with "U" qualifiers were multiplied by 0.5 before the mean was calculated.
-------
                                                   Table 6-2
                                    Exposure Point Concentrations for Soil
                                           Davis Park Road TCE Site
                    10.201
Chemical of
Potential
Concern
COPCs-Surface Soil
Inorganics
Aluminum
Arsenic
Beryllium
Lead
Manganese
Vanadium
Yttrium
COPCs-Suface/Subsurface Soil
Pesticides
Toxaphene
Inorganics
Aluminum
Arsenic
Beryllium
Lead
Manganese
Vanadium
                  Mean of Log        Standard
                  transformed    Deviation of Log
                     Data        transformed Data
                    (0 to 6 inches)
                               N(
                     2,
                    -0,
                     4,
                     5,
                     3,
                     2,
   158
   080
   688
   218
   835
   396
                  251
                  460
                  165
                  692
                  330
                  124
                     1.762
Yttrium
10
 1
 0
 3
 5
 3
 2
 (1) Number of Samples
.458
.834
.031
.894
.010
.958
.102
(2)
         0.499
 (8 to 16 feet)

         2.736         16

         0.144          6
         0.294          6
         0.096          6
         0.886          6
         0.173          6
         0.241          6
         0.365          6
; Upper Confidence Limit
H
Statistic

2.402
2.947
2.198
8.25
2.651
2.198
2.947
13.97
2.198
2.402
2.035
4.478
2.198
2.402
2.651
Maximum
Concentration
(mg/kg)
40000
15
1.1
630
360
56
17
10
52000
15
1.1
630
360
120
17
95%
UCL ( 2 )

36409.15
17.62
1.1
234176.36
288
52.69
23.99
6.53E+09
40555.63
8.96
1.1
428.40
180
69.76
13.48
 (3) The 95% UCL of the mean concentration represents the exposure point concentration for a chemical
maximum detected concentration.
Where the maximum detected concentration was exceeded," the maximum detected concentration was used
concentration.
                                                                                Exposure Point
                                                                                Concentration
                                                                                 (mg/kg)(  3 )
     36409.15
     15 (Max)
    1.1 (Max)
     630 (max)
       288
      52.69
      17 (Max)
      10.00

     40555.63
       8.96
     1.1 (Max)
       428
       180
      69.76
      13.48

 unless" it exceeded the

as the exposure point
-------
                                                 Table 6-3

                                            Carcinogenic Toxicity Data
                                            Davis Park Road TCE Site
Chemical
                       Weight   Oral Slope
                         of       Factor
                      Evidence  (mg/kg-day) -1
                                                        Tumor Type
                                         Animal     Reference a  Inhalation
                                         Species                Slope Factor
                                                                (mg/kg-day)  -1
                                                                      Tumor Type
                                                      Animal
                                                     Species
                                                                                                                                              Reference a
Volatiles
Bromodichloromethane
Chiorodibromomethane
Chloroform
1,1 -Dichloroethene

Methy-Tert-Butly-Ether
Tetrachloroethene
Trichloroethene
Pesticides
Dieldrin
Toxaphene
Inorganics
Aluminum
Arsenic
Beryllium
Lead
Manganese
Vanadium
Yttrium
Notes:
a = IRIS =
B2
C
B2
C
NC
C-B2
B2
B2
B2
6.2E-02
8.4E-02
6.1E-03
6.0E-01
_
5.2E-02
1.1E-02
1.6E+01
1.1E+00
                         NC
                          A
                         B2
                         B2
                         NC
                         NC
                         NC
1.5E+00
4.3E+00
  NTV
                                                       Kidney tumors
                                               Liver adenoma or carcinoma
                                                       Kidney tumors
                                               Adrenal phenochromocytomas
                                                            NA
                                                            NA

                                                      Liver carcinomas
                                            Liver carcinomas and neoplastic
                                                            nodules
           Skin cancer
Gross tumors, all site combine
Mouse
Mouse
Rat
Rat

NA
NA
Mouse
Mouse
IRIS
IRIS
IRIS
IRIS

NCEA
NCEA
IRIS
IRIS

NTV
-
-
-
NTV -
8.
1.

2.
6.
1.
1.
. 1E-02
.8E-01

, OE-03 NA
, OE-03
, 6E+01
, 1E+00
Liver carcinomas
Kidney
adenocarcinoma
NA
NA
Liver carcinomas
Based on oral SF
Mouse
Mouse

NA
NA
Mouse
-
IRIS
IRIS

NCEA
NCEA
IRIS
IRIS
Human
  Rat
IRIS
IRIS
IRIS
           Integrated Risk information System (IRIS, 1998) .
    NCEA = National Center for Environmental Assessment (EPA, 1998).
NA = Not available.
NC = Not classified as a carcinogen. NTV = No toxicity value available (EPA,
.5E+01
.4E+00
 NTV
Lung cancer
Human
Human
IRIS
IRIS
                                                                             1998; HEAST, 1997; IRIS, 1998).

-------
    D.  Risk Characterization

    The risk characterization integrates the toxicity and exposure assessments into quantitative
and qualitative expressions of risk. The output of this process is a characterization of the
Site related potential noncarcinogenic and carcinogenic health effects.

    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 RfD. By adding the HQs for all
contaminants within a medium or across all media to which a given population may be reasonably
exposed, the Hazard Index (HI)  can be generated. Calculation of a HI in excess of unity
indicates the potential for adverse health effects. Indices greater than one will be generated
anytime intake for any of the chemicals of concern exceeds its RfD. However, given a sufficient
number of chemicals under consideration, it is also possible to generate a HI greater than one
even if none of the individual chemical intakes exceeds their respective RfDs.

    Carcinogenic risk is expressed as a probability of developing cancer as a result of lifetime
exposure. Excess lifetime cancer risks are determined by multiplying the intake level with the
cancer potency factor. EPA's acceptable target range for carcinogenic risk is
one-in-ten-thousand (1E-4)  to one-in-one-million (1E-6).

    Cancer and noncancer risks for the current and future use scenarios for the Site are
summarized in Table 6-5.

SOIL

    As shown in this table,  the screening-level Reasonable Maximum Exposure  (RME) Hazard
Index for soil is below a level of concern for a commercial/industrial worker (HI=0.23) and for
adults residents (HI=0.22),  but is slightly above levels of concern for children (HI=1.47). This
value is due to contributions from aluminum, arsenic, and manganese. Because none of these
chemicals cause noncancer effects on the same target tissues, and because none of the
chemical-specific HQ values exceed a value of one,  it is concluded that exposure to soil is not
likely to pose a significant noncancer risk to children.

    Estimated RME excess cancer risks from soil to commercial/industrial workers (6.8E-06) and
residents (child plus adult=4.6E-05). This risk is due entirely to the presence of arsenic and
beryllium in soil.  The risk is contributed primarily by ingestion exposure. These risk levels
are within the range  (1E-04 to 1E-06) that are generally considered to be acceptable by EPA.
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                                       Table 6-5

                  Summary of Hazard Indices and Carcinogenic Risks
                        Reasonable Maximum Exposure Scenario
                              Davis Park Road TCE Site

               Scenario                        Total Hazard Index      Total Cancer Risk
Risks From Soil 1
Current Industrial/Commercial Worker                  0.086                  6.8E-06
Future Child Resident (EPS-2 and EPS-3)                1.47                  3.1E-05
Future Adult Resident (EPS-2 and EPS-3)                0.19                  1.5E-05
Combined Future Child
and Adult Resident (EPS-2 and EPS-3)                     -                   4.6E-05
Future Construction Worker  (EPS-4)                      0.23                  1.1E-06
Risks From Groundwater 2
Future Child Resident (EPS-2)                          5.10                  O.OE+00
Future Adult Resident (EPS-2)                          2.20                  O.OE+00
Combined Future Child
and Adult Resident (EPS-2)                               -                   O.OE+00
Future Child Resident (EPS-3)                          1.25                  3.9E-05
Future Adult Resident (EPS-3)                          0.54                  6.7E-05
Conbined Future Child
and Adult Resident (EPS-3)                               -                   1.1E-04
Combined Risks From Soil and Groundwater
Future Child Resident (EPS-2)                          6.61                  3.1E-05
Future Adult Resident (EPS-2)                          2.39                  1.5E-05
Conbined Future Child
and Adult Resident (EPS-2)                               -                   4.6E-05
Future Child Resident (EPS-3)                          2.72                  7.0E-05
Future Adult Resident (EPS-3)                          0.72                  8.2E-05
Combined Future Child
and Adult Resident (EPS-3)                               -                   1.5E-04

1 Risks from soil are the same for future child and adult residents in EPS-2 and EPS-3.
2 Risks from groundwater were estimated for the overburden aquifer  (EPS-2) and bedrock aquifer
(EPS-3).
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GROUNDWATER

Current Residential Wells

     Quantitative risk calculations were not performed for current residential wells, since only
one data point is available for each well, and this is not considered to be sufficient to derive
reliable risk estimates. Instead, the observed values were compared to existing risk-based
screening values and to State and Federal Drinking Water Standards in order to judge whether the
observed values might be in a range of concern. There are 9 known residential wells still in use
where concentrations of PCE or TCE or both exceed applicable State of Federal Drinking Water
Standards.

Center of the Plume Well Evaluation

     The only COPC in the overburden aguifer was MTBE. The screening level RME Hazard Index
would be in the range of concern for both children (HI=5.2)  and adults (HI=2.2)  if water from
the center of the overburden aguifer plume were used for drinking and showering. However, it
should be noted that MTBE was detected in only two wells, CW-2 (790 ug/L)  and CW-1  (14 ug/L).
These two concentrations were averaged to develop an exposure point concentration of 402 ug/L.
MTBE was not detected in an of the other overburden aguifer wells. The MTBE concentration of
709 ug/L is noticeably different than all of the other measurements which may indicate that it
is a possible outlier. Possible reasons for outliers may include inconsistent laboratory
procedures and/or contamination in field methods.

     No cancer risks were generated for future residents exposed to the overburden aguifer
groundwater since the only COPC is MTBE and MTBE is not classified as a carcinogen.

     The screening level RME Hazard Index in the bedrock aguifer is below a level of concern for
adults (HI=0.5), but would be slightly above a level of concern for children  (HI=1.3) if water
from the center of the plume were used for drinking and showering. This risk is primarily due to
TCE, with MTBE and chloroform. Because none of these chemicals are known to cause noncancer
effects on the same target tissues, and because none of the chemical-specific HQ values exceed a
value of one, it is concluded that exposure to groundwater at the center of the bedrock aguifer
groundwater plume is not likely to pose a significant noncancer risk to children.

     Estimated RME excess cancer risk to future residents (child plus adult) from water at the
center of the bedrock aguifer groundwater plume is 1.1E-04,  slightly above the usual acceptable
risk range of 1E-04 to 1E-06. This estimated excess cancer risk is due primarily to chloroform
(5.2E-05),  1,1-dichioroethene (3.6E-05) and PCE  (9.7E-06). These risks are derived about egually
between ingestion route (5.2E-05), and inhalation of volatiles while showering  (6E-05). Other
chemicals which contribute RME risks greater than 1E-06 include bromodichloromethane and TCE.

     E.   Uncertainties

     Table 6-6 summarizes the uncertainties and their probable direction of effect on the
evaluation of risk at the Davis Park Road Site. The net effect of these uncertainties depends on
their relative potential impacts. In general, the potential magnitude of effect of the factors
that tend to overestimate risk would be expected to outweigh the potential magnitude of effect
of the factors that tend to underestimate risk or for which the direction of effect is unknown.

     The results of this uncertainty analysis suggest, based on the integration of all key
assumptions used in the risk assessment, that risks associated with the Davis Park Road Site
have been overestimated.

     F.   Conclusions

     Actual or threatened releases of hazardous substances from this Site if not addressed by
implementing the response action selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
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                                         Table 6-6

                                Summary of Uncertainty Analysis
                                   Davis Park Road TCE Site
    Uncertainty Element
 Potential for
Overestimation
     Effects on Risk Estimate
 Potential for    Potential for Over or
Underestimation     Underestimation
Exposure Parameter Estimation

•      Media intake rates                    Moderate
•      Groundwater characterization          Moderate
•      Exposure frequencies                  Moderate
•      Exposure to soil
•      Exposure durations                    Moderate
•      Exposure point concentration for
      volatiles in groundwater

Toxicity Data

•      Use of chronic RfDs for estimating      High
      noncancer risk in children
•      Cancer slope factors                    High

         - 1,1-Dichloroethene                 High
         - Tetrachloroethene

•      Reference doses                         High
         - 2 methyl naphthalene               High
         - Naphthalene                        High
         - Phenanthrene                       High
                                                 High
                           Moderate
                                             High
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SECTION 7. APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS  (ARARS)

           The requirement that ARARs be identified and complied with and the development
and implementation of remedial actions is found in Section 121(d)(2) of CERCLA, 42 U.S.C.
Section 9621(d)(2). This section requires that for any hazardous substance remaininq on-site,
all federal and state environmental and facility citinq standards, requirements, criteria, or
limitations shall be met at the completion of the remedial action to the deqree that those
requirements are legally applicable or appropriate and relevant under the circumstances
presented at the Site.

           Three classifications of requirements are defined by EPA in the ARAR determination
process.

       •       Chemical-specific:  These requirements set protective remediation levels for the
              chemicals of concern.

       •       Location-specific:  These requirements restrict remedial actions based on the
              characteristics of the site or its immediate surroundinqs.

       •       Action-specific:  These requirements set controls or restrictions on the design,
              implementation,  and performance levels of activities related to the manaqement of
              hazardous substances,  pollutants,  or contaminants.

       A.  Chemical-Specific ARARs

           Chemical-specific ARARs include those laws and requlations qoverninq the release
of materials possessinq certain chemical or physical characteristics, or containinq specified
chemical compounds. Chemical-specific requirements set health- or risk-based concentration
limits or ranqes in various environmental media for specific hazardous substances, contaminants,
and pollutants. These ARARs, when applied to site-specific conditions, establish numerical
values that define the acceptable amount or concentration of a chemical that may be found in, or
discharqed to, the ambient environment. Examples include drinkinq water standards and ambient
air quality standards. Chemical-specific ARARs are established once the nature of the
contamination at the site has beendefined, which is accomplished durinq the RI.
Chemical-specific ARARs for this Site are listed in Table 7-1.



B.    Location-Specific ARARs

      Location-specific ARARs are desiqn requirements or activity restrictions based on the
qeoqraphical or physical positions of the Site and its surroundinq area.  Location-specific
requirements set restrictions on the types of remedial activities that can be performed based on
site-specific characteristics or location. Examples include areas in a flood plain, a wetland,
or a historic site. Location-specific criteria are qenerally established early in the RI/FS
process since they are not affected by the type of contaminant or the type of remedial action
implemented. Location-specific ARARs for this Site are listed in Table 7-2.

C.    Action-Specific ARARs

      Action-specific ARARs are technoloqy-based, establishinq performance, desiqn, or other
similar action-specific controls or requlations for activities related to the manaqement of
hazardous substances or pollutants. Action-specific requirements are triqqered by the particular
remedial alternatives that are selected to accomplish the cleanup of hazardous wastes.
Action-specific ARARs for this Site are provided in Table 7-3.

D.    Media of Concern

      Based on the results of the remedial investiqation and the baseline risk assessment, the
Davis Park Road Site has one contaminated media; qroundwater.
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TABIiE 7-2 - LOCATION-SPECIFIC ARARS, CRITERIA, AND GUIDANCE

Standard, Requirement, Criteria,      Citation              Requirements Synopsis
or Limitation
                                                         Comment
Federal
Resource Conservation and
Recovery Act  (RCRA),  as amended

   RCRA Location Standards
42 USC 6901
                                      40 CFR 264.18(b)
Fish and Wildlife Conservation Act
                                      16 USC 2901 et seq.
                      A treatment/storage/
                      disposal (TSD) facility
                      must be designed,
                      constructed, operated, and
                      maintained to avoid
                      washout on a 100-year
                      floodplain.

                      Requires states to identify
                      significant habitats and
                      develop conservation plans
                      for these areas.
                               May be relevant and
                               appropriate if an onsite TSD
                               facility is required as part of
                               overall remediation and it
                               exists within the 100-year
                               floodplain.
                               Confirmation with the
                               responsible state agency
                               regarding the Site being
                               located in one of these
                               significant habitats.
Floodplain Management Executive
Order
Executive Order
11988; 40 CFR 6.302
Actions that are to occur in
floodplain should avoid
adverse effects, minimize
potential harm, restore and
preserve natural and
beneficial value.
Remedial actions are to
prevent incursion of
contaminated groundwater
onto forested floodplain.
Endangered Species Act
16 USC 1531
Requires action to
conserve endangered
species or threatened
species, including
consultation with the Dept
of Interior.
Endangered species thus far,
have not been identified at
the Site.
Wetlands Management Executive
Order
Executive Order
11990; 40 CFR 6.302
Action to minimize the
destruction, loss or
degradation of wetlands.
Relevant and appropriate if
remediation occurs in
wetlands.
State
North Carolina Hazardous Waste
Management Rules
ISA NCAC 13A
                      Location requirements for
                      hazardous waste
                      treatment/storage/disposal
                      facilities.
                               May be applicable to
                               hazardous waste excavated,
                               stored, and treated on-site
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North Carolina Solid Waste
Management Rules
ISA NCAC 13B
                      Siting reguirements for
                      solid waste disposal units.
May be relevant and
appropriate to nonhazardous
waste disposed on-site.
Davis Park Road TCE Site
Record of Decision
Gastonia, Gaston County, NC
September, 1998
                                                                     7-4
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SECTION 8.REMEDIAL ACTION OBJECTIVES

        Considering the requirements for risk reduction and the risk-based remediation levels
derived in the Baseline Risk Assessment, and the ARARs discussed previously, the remediation
goals specifically developed for groundwater across the entire Site are presented in Table  8-1.
The goal of the Remedial Action for the Site is to limit exposure to groundwater contaminated
above risk based standards and to restore groundwater to below risk based standards.

        The remediation goals were selected as the most conservative of the chemical specific
ARARs or the health-based risk goals. The contract required quantitation limit  (CRQL) was chosen
if the chemical-specific ARAR was below this limit. The background concentration would have been
selected as the remediation goal if it had exceeded the risk-based goal, as is  the normal
procedure.
TABLE 8-1 - REMEDIATION GOALS FOR GROUNDWATER AT THE DAVIS PARK ROAD SITE

  CONTAMINANTS OF            MAX  (UG/L)          REMEDIATION            BASIS
      CONCERN                                    GOAL  (UG/L)

Tetrachloroethene  (PCE)         14                     1          CRQL  (NCGS 0.7 ug/1)
TrichloroethenE  (TCE)           34                   2.8         NC 2L GS
1,1-Dichloroethene              3.8                    7          SDWA, NC 2L GS
(1,1-DCE)
Chloroform  (CLFM)               40                     1          CRQL  (NC 2L GS - 0.19 ug/1)
Methy-ter-butyl ether           709                  200         NC 2L GS
(MTBE)

Notes: SDWA- Federal Safe Drinking Water Act, CRQL - Contract Required Quantitation
Limit; NC 2L GS - North Carolina Administrative Code Subchapter 2L Groundwater Standard
SECTION 9.  DESCRIPTION OF ALTERNATIVES

    Table 9-1 lists the remedial action alternatives developed for the Davis Park Road Site.
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TABIiE 9-1.  REMEDIAL ACTION ALTERNATIVES FOR GROUNDWATER AT THE SITE.
        NUMBER

Alternative 1


Alternative 2
                                     NAME
Alternative 3
Alternative 4
Alternative 5
No Action
Limited Action
Reduction of Groundwater
Exposure and Monitored
Natural Attenuation
Reduction of Groundwater
Exposure and Groundwater
Treatment
Reduction of Groundwater
Exposure and Groundwater
Pump and Treat
         DESCRIPTION

Site is left "as is":
Five-year reviews conducted

Deed recordations
Semi-annual, and annual groundwater
monitoring
Five-year reviews conducted

City Water connections
Wellhead treatment
Quarterly and annual groundwater monitoring
Natural Attenuation Study
Five-year reviews conducted

City Water connections
Wellhead treatment
Semi-annual and annual groundwater
monitoring
Treatment of contaminated groundwater
Five-year reviews conducted

City Well connections
Wellhead treatment
Semi-annual and annual groundwater
monitoring
Pump and Treat contaminated groundwater
Five-year reviews conducted
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     Descriptions of the alternatives developed for remediation of groundwater are discussed
below. All of the alternatives except the "No Action" alternative include periodic monitoring of
the groundwater including monitoring wells and potable wells for site contaminants to evaluate
the site conditions and the migration of contaminants over time.

A.   ALTERNATIVE 1 - NO ACTION

     Under the No Action alternative, the Site is left "as is," and no funds are expended for
active control of the groundwater contaminant plume or for reducing the exposure of residents to
contaminated groundwater. The NCP requires consideration of this alternative as a baseline for
comparing other remedial actions and the level of improvement achieved. However, five-year
reviews of the Site remediation decision, which consist of one round of sampling of selected
monitoring and potable wells, would be conducted over an estimated 30-year period.

B.   ALTERNATIVE 2 - INSTITUTIONAL CONTROLS

     In this alternative, deeds in the area would be required to record the fact that
groundwater contamination exists under the property, and if a potable well is constructed, a
strong possibility exists that the water will be contaminated with unacceptable levels of
volatile organic contaminants. These recordations would remain in place until the groundwater
quality would allow unrestricted use.

     Semi-annual groundwater monitoring would be conducted on both monitoring wells and potable
drinking water wells for five years. Three more upgradient wells would be installed after five
years to track the trailing edge of the plume as the concentration of the COCs decreases in
upgradient wells. Thereafter, the existing and new monitor wells will be sampled annually for 25
years. Wells would be sampled for volatile organic compounds. The five-year reviews would be
required because concentrations of chemicals remain at the Site above levels that allow
unlimited use of the groundwater.

C.   ALTERNATIVE 3 - REDUCTION OF GROUNDWATER EXPOSURE AND MONITORED NATURAL ATTENUATION

     Under this alternative, all homes, churches, and businesses impacted by the Davis Park Road
TCE Site not currently connected to the City of Gastonia public water supply would be connected.
In addition, residents will also be given the option to obtain wellhead treatment of their
private well, i.e. groundwater treatment such as a carbon filter unit would be connected to the
private water supply well. The EPA will provide for maintenance of the carbon filter for one
year.

This alternative also includes monitoring of groundwater from approximately 18 wells on a
quarterly basis for 3 years. As in Alternative 2, three additional monitor wells will need to be
installed. After installation, all existing monitor wells and the new wells will continue to be
sampled on an annual basis for the next 27 years. However, monitoring will be ceased when
groundwater has reached Site Remediation goals. Wells would be sampled for volatile organic
compounds.

In concert with the quarterly groundwater sampling, a Natural Attenuation study will be
completed on the bedrock aquifer plume. Much of the data required for the Natural Attenuation
study has already been collected during the RI, however,  additional data are needed. This data
includes groundwater geochemical data, hydrogeologic parameters, and other necessary information
to prove that the bedrock aquifer contaminant plume is in fact naturally attenuating.

As stated earlier, based on the results of the BIOSCREEN model, the groundwater contaminant
plume concentrations are expected to meet remediation goals approximately 7 years from the
present time.

     The five-year reviews would be required because concentrations of chemicals remain at the
Site above levels that allow unlimited use of the groundwater.

D.   ALTERNATIVE 4 - REDUCTION OF GROUNDWATER EXPOSURE AND GROUNDWATER TREATMENT

     This alternative would include all the provisions for prevention of exposure of current
residents to contaminated groundwater described in Alternative 3, plus adds treatment of the
-------
contaminated bedrock aquifer groundwater plume. The major component of the groundwater treatment
option includes in-well vapor stripping.

     The in-well vapor stripping technology would be used throughout the plume. It is projected
that at least three air-stripper wells would be installed to treat the contaminated bedrock
aguifer plume. The remedy would be designed so that it will not be overly intrusive to the
neighborhood.

     Groundwater treatment is expected to last approximately 10 years. Natural attenuation
processes were not figured into the calculation of treatment duration. Therefore,  the estimated
time groundwater treatment is required may be overestimated. Groundwater monitoring will be
conducted semi-annually for the first five years, and annually for the next 25 years. However,
groundwater monitoring will be ceased when groundwater has reached Site Remediation goals.

E.   ALTERNATIVE 5 - REDUCTION OF GROUNDWATER EXPOSURE AND GROUNDWATER PUMP AND TREAT

     This alternative includes all of the provisions for prevention of exposure of current
residents to contaminated groundwater described in Alternative 3, plus adds active treatment of
the contaminated bedrock groundwater plume using pump and treat. The major component of this
system is the installation of extraction wells into the bedrock aquifer. It is estimated that at
least three extraction wells would need to be installed. The contaminated groundwater is
extracted through the wells and treated at the ground surface using activated carbon to remove
VOC contaminants. The treated water is then discharged to an acceptable location,  either a
public-owned wastewater system or to a nearby stream.

     The groundwater treatment is expected to last approximately 10 years. Natural attenuation
processes were not figured into the calculation of treatment duration. Therefore,  the estimated
time groundwater treatment is required may be overestimated. Groundwater monitoring will be
conducted semi-annually for the first five, years, and annually for the next 25 years. However,
groundwater monitoring will be ceased when groundwater has reached Site Remediation goals.

SECTION 10. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES

     In this section, each alternative is assessed using seven evaluation criteria required
under CERCLA. Comparison of the alternatives with respect to these evaluation criteria are
presented in summary form. This approach is designed to provide sufficient information to
adequately compare the alternatives, aid in the selection of an appropriate remedy for the Site,
and demonstrate satisfaction of the statutory requirements.

       •      Each alternative is evaluated in terms of its ability to:

       •      Be protective of human health and the environment.

       •      Attain ARARs or provide grounds  for invoking a waiver.

       •      Use permanent solutions and alternative treatment technologies or resource recovery
              technologies to the maximum extent practicable.

       •      Satisfy the preference for treatment that reduces toxicity,  mobility,  or volume of
              the hazardous substances,  pollutants and contaminants as a principal element.

       •      Be cost-effective.

     The seven evaluation criteria required to address the above CERCLA requirements serve as
the basis for conducting the detailed analysis. The evaluation criteria are briefly described
below.

  1. Overall Protection of Human Health and the Environment determines whether each alternative
     meets the requirement that it be protective of human health and the environment in both
     short- and long-term, from unacceptable risks posed by hazardous substances,  pollutants, or
     contaminants. This criterion is of key importance. While the remedy selected may on
     occasion seek a waiver of a given ARAR, the remedy selected must be protective of human
     health and the environment.
-------
  2. Compliance with ARARs is used to determine how each alternative complies with federal and
     state ARARs as defined in CERCLA Section 121, as discussed in Section 2, or provide grounds
     for invoking one of the waivers.

  3. Short-Term Effectiveness addresses the impacts of the alternatives during the construction
     and implementation phase until remedial response objectives have been met. Alternatives are
     evaluated with respect to their short-term effects on human health and the environment.

  4. Long-Term Effectiveness and Permanence addresses the results of a remedial action in terms
     of the risk remaining at the Site after response objectives have been met. The primary
     focus of this evaluation is the effectiveness of the controls that will be applied to
     manage risk posed by treatment residuals or untreated wastes.

  5. Reduction of Toxicity, Mobility,  and Volume addresses the statutory preference for
     selecting remedial actions that employ treatment technologies that permanently and
     significantly reduce toxicity, mobility, or volume of the hazardous substance as their
     principal element. This preference is satisfied when treatment is used to reduce the
     principal threats at the Site through destruction of toxic contaminants, irreversible
     reduction in contaminant mobility, or reduction of total volume of contaminated media.

  6. Implementability addresses the technical and administrative feasibility of implementing an
     alternative and the availability of various services and materials reguired during its
     implementation.

  7. Cost estimates for the FS are expected to provide an order-of-magnitude evaluation for
     comparison of alternatives and are based on the site characterization developed in the RI.
     Capital cost, annual cost, and a present worth analysis are part of this evaluation. The
     present worth represents the amount of money that, if invested in the initial year of the
     remedial action at a given rate,  would provide the funds reguired to make future payments
     to cover all costs associated with the remedial action over its planned life. The baseline
     present worth is computed at a discount (interest) rate of 7 percent over a 30 year period.
     Appendix A contains spreadsheets showing each component of the present worth costs.

     The first two criteria are referred to in the RI/FS guidance manual (EPA 1988) as the
"threshold factors", implying that for further consideration of an alternative, these two
criteria must be satisfied. Alternatives which do not satisfy these threshold factors are not
feasible (40 CFR 300.430(f)(1)(I)(A).  Criteria 3 through 7 are referred to as "primary balancing
factors" (page 4-25 of RI/FS manual),  implying that these criteria are used to select the
alternative among the feasible alternatives. There are two other criteria,  state acceptance and
community acceptance, which are provided by state and local agencies and the public. These
criteria will be evaluated in the responsiveness summary. A detailed analysis of the
alternatives using the above criteria is presented below.

A.   Alternative 1 - No Action

     Section 300.430 (e) of the NCP reguires that the "no action" alternative be carried forward
for consideration in the detailed analysis of alternatives as a baseline for comparison of the
other alternatives. Under the no action alternative, funds are not expended for routine
monitoring, control, or cleanup of groundwater contamination associated with the Site. Funding
would, however, be reguired for the five-year review.

Overall Protection of Human Health and the Environment

     This alternative would not provide any increased protection to human health or the
environment. Residents in the vicinity of the Site would continue to drink water from private
wells that contain contaminants above the remediation goals. However, since soils at the Site
did not contain any significant amounts of contamination, the concentration of contaminants in
the groundwater would be expected to decrease with time due to natural attenuation and
degradation. Under this action, monitoring or verification of the decrease would be conducted
only at the five-year review stage.

Compliance with ARARs
-------
     The "no action" alternative would not address compliance with ARARs since there would be no
active measures taken to reduce the contaminant concentrations. The volatile organic contaminant
concentrations. Would be expected to decrease with time due to natural attenuation and
degradation. Location- and action-specific ARARs do not apply to this alternative since further
remedial action would not be conducted.

Short-Term Effectiveness

     Because no activities would be implemented, there would be no additional impact on the
community. Also, no construction or operation related impacts to the environment would occur,
since no site activities would be performed.

Long-Term Effectiveness and Permanence

     Because remedial actions would not occur, this alternative would not provide any long-term
effectiveness or permanence. The long term risks caused by the contaminated groundwater would
not be addressed. However, since the Site soils did not contain any significant amounts of
contamination,  the concentration of contaminants in the ground water would be expected to
decrease with time due to natural attenuation and degradation.

Reduction of Toxicity, Mobility, and Volume

     The "no action" alternative would provide no reduction in toxicity, mobility, or volume of
contaminated groundwater.

Implementability

     This criterion is not applicable because remedial activities would not occur.

Cost

     The cost of this alternative consists only of 5-year review expenses. The total present
worth cost for this alternative is approximately $140,055.

B.  Alternative 2 - Institutional Controls

    This alternative includes deed recordations and groundwater monitoring to protect human
health and the environment. Under this alternative, no groundwater remedial measures will be
undertaken at the Site, Five-year reviews are reguired under the NCP to determine if
contaminants which remain on-site are causing additional risk to human health or the
environment. As a result of this review,  EPA will determine if additional site remediation is
reguired. Five-year reviews are assumed to be conducted for a 30-year period.

     Deed recordations would reguire amending the property deed to note that contaminated
groundwater is located on the property. These recordations would be reguired on properties
within the extent of the groundwater plume. These recordations would remain in place until the
groundwater guality improved enough to allow for unrestricted use.

     Groundwater will be monitored semi-annually for five years and annually for 25 years at
approximately 18 existing monitoring, converted residential, and residential wells. Groundwater
will be collected and analyzed for VOCs.

Overall Protection of Human Health and the Environment

     Deed recordations would alert residents of the potential hazards associated with the
contaminated groundwater. They would limit exposure by warning of unlimited use of the
groundwater, however, the recordations would not completely eliminate the risk of exposure or
control the plume migration. Conseguently, this alternative would not provide active protection
of human health and the environment, although natural attenuation and degradation of
contaminants may be occurring. Monitoring would reveal future threats to human health and the
environment.

Compliance with ARARs
-------
     This alternative does not achieve the remedial action objectives of chemical-specific ARARs
established for groundwater. Through natural attenuation and degradation,  a decrease in the
contaminant concentration would be expected with time. Location- and action-specific ARARs do
not apply to this alternative since further remedial actions of an intrusive nature would not be
conducted.

Short-Term Effectiveness

     Implementing this alternative would reguire approximately one year. Groundwater monitoring
could begin immediately. No significant environmental impacts would be expected during the
sampling events.

Long-Term Effectiveness and Permanence

     Properly implemented deed recordations would make residents aware of the contamination and
thus potentially prevent ingestion and direct contact with contaminated groundwater, thereby
reducing
risk to potential users. Implementation of deed recordations with continued monitoring would be
reguired indefinitely. The long term monitoring results and the actual effectiveness of the deed
recordations would reguire periodic reassessment to determine the continued effectiveness of
this alternative. If the degree of protectiveness to human health is insufficient,  further
remedial actions would have to be implemented.

Reduction of Toxicity, Mobility,  and Volume

     This alternative would not actively reduce the volume, toxicity or mobility of the
contaminants.

Implementability

     This alternative would be readily implemented since there are no remedial activities of an
intrusive nature being performed. The implementation of monitoring would present no
difficulties.  Implementing and enforcing deed recordations would reguire the cooperation of the
state and local governments. The deed recordations may be subject to change in legal and
political interpretations over time. Voluntary acceptance by adjacent property owners is
guestionable.  Conseguently, present or future property owners could choose to ignore or be
unaware of the deed recordations. The recordation could also be lost during future property
transfers. For the above reasons, the reliability of groundwater use deed recordations is
considered uncertain. Legal services, field personnel and analytical laboratories necessary for
implementation of this alternative are readily available. If additional monitor wells are
reguired, well drilling services are readily available. Monitor eguipment is readily available
for groundwater sampling.

Cost

     The total estimated present worth cost for this alternative is $990,225. Capital costs
associated with this alternative include fees for implementing deed recordations and sampling
eguipment for monitoring. The O&M costs include long-term monitoring activities, which have been
evaluated for a 30-year period.

C.  Alternative 3 - Reduction of Groundwater Exposure and Monitored Natural Attenuation

    Under this alternative, all homes, churches, and businesses impacted by the Davis Park Road
TCE Site not currently connected to the City of Gastonia or Gaston County public water supply
would be connected. The Davis Park Road Site area is generally defined in Figure 1-1 of this
Record of Decision, EPA will determine during the Remedial Design which homes, churches and
businesses have been or may become impacted by Site contaminants. In addition, residents will
also be given the option to obtain wellhead treatment of their private well.

     If reguested, agueous phase activated carbon units for removal of organics from groundwater
supply would be installed at the wellhead of each residential well. Filtration will also be used
as a precursor to the carbon treatment units. Groundwater treatment at the wellhead will consist
of the installation of a filtration unit and granular activated carbon  (GAG) unit.  Both of the
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filter systems will be installed in-line on present residential water systems. The systems will
be designed to remove particulates from the influent groundwater as well as any organics
present. EPA will maintain the carbon filters for a period of one year.

     The first filtering unit of the in-line treatment system will consist of a particulate
filter for removal of sediment and other matter from the influent water line. Following the
particulate filter, the feed water will flow into a GAG system, The GAG system will consist of
two units operated in a downflow fixed-bed mode, as it has been found to be most cost effective
and produces the lowest effluent concentrations for low solids feed streams. Due to space
constraints, each unit will contain a maximum of 50 pounds of carbon and will be replaced on a
semi-annual to annual basis. Spent carbon will be taken offsite for regeneration or disposal.

     To assess the effectiveness of the treatment system,  the water effluent will be routinely
monitored. Monitoring will be more freguent during startup and early operation.

     This alternative also includes monitoring of groundwater from approximately 18 monitoring
wells for 3 years on a guarterly basis and for 27 years on an annual basis. However, groundwater
monitoring will be ceased when groundwater has reached Site Remediation goals.

     All connections to the city water system would reguire assistance from state and local
authorities, especially in the areas of public notification,  system design, and system
construction. During initial procedures, an accurate count of the number of residences that are,
or may be potentially affected by the groundwater contaminant plume would have to be determined.
Once determined, EPA, state and local authorities would have to notify each resident and present
the positive and negative aspects of a public water connection. Recognition of the fact that
some residents will not want to accept public water supply connection is understood. After
notification of the public, system design will begin. System design will reguire agreement
between local authorities and EPA as to the total number of connections and total extent of
pipeline. Following completion of the system design, system construction will commence. The
system will most likely be installed by the local authority or gualified contractor.

     The guarterly groundwater sampling for VOCs will be augmented with the collection of
additional data to support the assumption that contaminants in the bedrock aguifer groundwater
plume are naturally attenuating. The evaluation will be conducted in accordance with Region IVs
Draft Region 4 Approach to Natural Attenuation of Chlorinated Solvents. For the first year,
these additional samples will be collected, and combined with data collected during the RI, will
comprise the Natural Attenuation Study. The conclusions of the study will be published in a
report by EPA.

Overall Protection of Human Health and the Environment

     This alternative provides protection to residents from contaminated groundwater during an
extended period of time, especially for those connected to the City of Gastonia public water
supply system. Therefore, risks to current and potential groundwater users are expected to
decrease. In addition, natural attenuation processes provide protection to human health and the
environment by using natural processes, including intrinsic biodegradation and dispersion, to
reduce contaminant levels.

Compliance with ARARs

     Under this alternative, groundwater recovered from the wellhead treatment will be treated
such that contaminant concentrations in the effluent will be below the remediation goals.
Natural attenuation processes are expected to decrease the contaminant concentrations. The
Natural Attenuation Study conducted during the Remedial Design will provide the data necessary
to prove that contamination is naturally attenuating and more accurately predict the rate of
decrease.

Short-term Effectiveness

     Appropriate levels of protection will be used during installation of the treatment system
and connection of residents to the city water supply. Disposal of any wastes generated during
construction and operation will follow proper handling practices and no exposure or
environmental impacts are expected.
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Long-term Effectiveness and Permanence

     Connecting affected residents to the city water supply will provide a permanent remedy for
protection of human health. The wellhead treatment would reguire regular maintenance by the
resident. Groundwater monitoring will continue to occur regularly during implementation of this
alternative. There will be a remaining risk associated with groundwater use for an estimated 7
years.

Reduction of Toxicity, Mobility, and Volume

     Treating the groundwater by agueous phase GAG will reduce the concentrations of organics in
the groundwater to the remediation goals, and therefore, the toxicity and volume. Natural
attenuation processes may also act to reduce the overall concentration of the contaminant plume.

Implementability

     This alternative involves installation of in-line groundwater treatment units,  including
filtration units and activated carbon units. These components are widely available and the
system can be assembled using standard engineering and construction technigues. All of the units
of the treatment system are easily transportable and installed. For the organic contaminants
detected at the Site, carbon adsorption is a proven technology and is often used as a means for
treatment. Permission will be reguired from the respective property owners for the installation
of carbon units.

     Water lines currently used by the city are adjacent to many of the residences at the Site
and would only reguire extensions of the lines to connect new residences. Permits and designs
would have to be obtained by the local authority or gualified contractor.

Cost

     Costs associated with the connection of residences to the public water supply include
public notification, system design, and system construction. For estimating purposes, EPA
assumed 75 residents would be connected to city water. Capital costs associated with the
groundwater treatment unit portion of the alternative includes installation of the filter and
carbon adsorption units, and other associated instrumentation and eguipment. For estimating
purposes, EPA assumed that 75 residents would reguest wellhead treatment with operation and
maintenance for a period of 1 year. Capital costs for the Natural Attenuation Study have been
estimated. The estimated total present worth cost for this alternative is $3,873,299.

D. Alternative 4 - Reduction of Groundwater Exposure and Groundwater Treatment

     This alternative includes all the provisions for prevention of exposure of current
residents to contaminated groundwater described in Alternative 3, plus adds remediation of the
groundwater that contains contaminant concentrations above the remediation goals. The major
component of the groundwater treatment option includes in-well vapor stripping..

     The in-well VOC removal system volatilizes VOCs contained in groundwater and removes them
as a vapor. The vapor is retrieved using vacuum extraction and is treated above ground by
adsorption onto granular activated carbon (GAG).  The VOC-enriched vapor is extracted and the
partially cleaned water is returned to the aguifer. The system recirculates the groundwater
through air-lift pumping. The system converts groundwater contamination into a vapor that is
vacuum-extracted and treated. At the same time, air-lift pumping circulates the groundwater,
which becomes cleaner with each pass through the in-well air stripper. The only input to the
system is gas, which is injected into the well. The injected gas is typically air and can be
recycled during the process.

     The only output of the system is gas that is removed from the well; this gas contains the
VOCs removed from the groundwater. After removal, this VOC vapor is adsorbed onto GAG. The GAG
is regenerated and reused. No major facilities are needed for this technology. Power is needed
to operate the pumps and compressors. The method itself involves no moving parts beneath the
ground surface, however, careful packer and well designs would be reguired to successfully
divert the groundwater from the well back into the saturated zone and to the water table.
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     The system is expected to operate approximately 10 years. After 10 years of operation, the
treatment system will be evaluated for its effectiveness and the decision will be made on the
continuation of this treatment. Groundwater monitoring will be conducted semi-annually for the
first five years, and annually for twenty five years thereafter. However, groundwater monitoring
will be ceased when groundwater has reached Site Remediation goals.

    Overall Protection of Human Health and the Environment

    This alternative would provide significant protection of human health and the environment
through groundwater remediation and connection of residents to the city water supply.

    Compliance with ARARs

    Under this alternative, groundwater will be treated such that the contaminant concentrations
in the effluent will be below remediation goals. This treatment option will comply with
chemical-, location-, and action-specific ARARs.

    Short-Term Effectiveness

    During installation of the treatment system, the usual precautions necessary for
construction activities will be taken. The installation of wells and the treatment system will
not involve a significant release of volatiles to the environment. Disposal of any wastes
generated during construction and operation would follow established handling practices.

    Long-Term Effectiveness and Permanence

    The use of treatment processes provides a permanent method for treating the VOC contaminants
in the groundwater. Spent carbon will be disposed in an approved facility or regenerated
off-site.

    Reduction of Toxicity, Mobility and Volume

    Pumping at the wells would capture the plume and thus reduce plume mobility. Treating the
groundwater would remove VOCs present in the groundwater to the remediation goals, thus reducing
the toxicity and volume of groundwater contamination. This process would not release VOCs to the
atmosphere.

    Implementability

    This alternative involves installation of groundwater extraction wells, small pumps,
compressor, and GAG canisters, in addition to electrical connections. These components are
widely available and the system can be assembled using common construction technigues. All the
units of the treatment system are easily transportable and installed.

    Cost

    The total present worth cost for this alternative is approximately $7,014,434. Total capital
costs are estimated to be $2,879,874.

E. Alternative 5 - Reduction of Groundwater Exposure and Groundwater Pump and Treat

    This alternative includes all the provisions for prevention of exposure of current residents
to contaminated groundwater described in Alternative 3, plus adds remediation of the groundwater
that contains contaminant concentrations above the remediation goals. The major component of the
groundwater treatment option includes groundwater extraction and treatment.

    The groundwater pump and treat system involves the use of extraction wells to remove
contaminated groundwater from the bedrock aguifer via pumping and discharge to an air stripping
system that volatalizes the VOCs. The vapor is retrieved using vapor vacuum extraction and is
treated by adsorption onto GAG or is released without treatment to the atmosphere. The treated
water exits the air stripping system and is discharged to a local surface water body, which in
this case would be Blackwood Creek. An NPDES permit will be reguired prior to any discharge and
the permit will define levels of constituents that may be present in the treated water.
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    System requirements include power for operation of the pumps and air stripping system. The
air stripping system is built to be able to operate in the open environment. However, costs have
been included for the system to be housed within a building for protection against the elements
and human interference.

    The system is expected to operate approximately 10 years. After 10 years of operation, the
treatment system will be evaluated for its effectiveness and the decision will be made on the
continuation of this treatment. Groundwater monitoring will be conducted semi-annually for the
first five years, and annually for twenty five years thereafter. However, groundwater monitoring
will be ceased when groundwater has reached Site Remediation goals.

    Overall Protection of Human Health and the Environment

    This alternative would provide significant protection of human health and the environment
through groundwater remediation and connection of residents to the city water supply.

    Compliance with ARARs

    Under this alternative, groundwater will be treated such that the contaminant concentrations
in the effluent will be below remediation goals. This treatment option will comply with
chemical-, location-, and action-specific ARARs.

    Short-Term Effectiveness

    During installation of the treatment system, the usual precautions necessary for
construction activities will be taken. The installation of wells and the treatment system will
not involve a significant release of volatiles to the environment. Disposal of any wastes
generated during construction and operation would follow established handling practices.

    Long-Term Effectiveness and Permanence

    The use of treatment processes provides a permanent method for treating the VOC contaminants
in the groundwater. Spent carbon will be disposed in an approved facility or regenerated
off-site.

    Reduction of Toxicity, Mobility and Volume

    Pumping at the wells would capture the plume and thus reduce plume mobility. Treating the
groundwater would remove VOCs present in the groundwater to the remediation goals, thus reducing
the toxicity and volume of groundwater contamination.

    Implementability

    This alternative involves installation of groundwater extraction wells, small pumps, air
stripping system and GAG canisters, in addition to electrical connections. These components are
widely available and the system can be assembled using common construction techniques.  All the
units of the treatment system are easily transportable and installed.

    Cost

    The total present worth cost for this alternative is approximately $4,543,480. Total capital
costs are estimated to be $2,018,869.

F. Comparative Analysis of Alternatives

    Presented in Table 10-1 are ranking scores for each evaluation criteria, excluding cost.
Each alternative's performance was ranked on a scale of zero to five, with zero indicating none
of the criteria's requirements were met, and five indicating all of the requirements were met.
The ranking scores are not intended to be quantitative or additive. They are summary indicators
only of each alternative's performance against the evaluation criteria. The ranking scores
combined with the present worth costs provide the basis for comparison among alternatives.
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    Under overall protection, the no action alternative  (Alternative 1) is ranked the lowest
 ("0") since contaminated groundwater is left onsite with no further actions being conducted.
Alternative 2 is ranked slightly higher ("1") since deed recordations will be implemented in an
attempt to limit contact with the contaminated groundwater. Alternatives 4 and 5 are ranked
higher  ("5") than Alternative 3  ("4") since these alternatives provides for treatment of the
entire contaminant plume.

    Under compliance with ARARs, Alternatives 1 and 2 are ranked the lowest ("0") since
contaminated groundwater remains onsite and chemical-specific ARARs are not met. Alternative 3
is ranked lower than Alternatives 4 and 5 since ARARs will not be met over the entire plume.

    Under long-term effectiveness, the no action alternative is ranked the lowest since
contaminated groundwater would be left onsite with no further actions being conducted.
Alternative 2 is ranked slightly higher since deed recordations would somewhat limit contact
with the contaminated groundwater. Alternative 4 and 5 are ranked highest since contaminated
groundwater over the entire plume would be remediated.

    Under reduction of T/M/V, Alternatives 1 and 2 are ranked the lowest since contaminated
groundwater remains as is. The mobility, toxicity, and volume are reduced in Alternatives 3, 4
and 5, however, to a greater extent in Alternatives 4 and 5.

    Under short-term effectiveness and implementability, Alternative 1 is ranked the highest
since no further actions are being conducted, Alternative 2 is ranked next since the only
actions taking place are deed recordations and groundwater monitoring. The remaining
alternatives are ranked egually.
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Table 10-1. Comparative Analysis of Alternatives
                         1- No Action
    Implementability

    Present Worth Costs
                   2-        3-Reduction of GW
              Institutional     Exposure and
                 Controls     Monitored Natural
                                Attenuation
                                    4-Reduction of   5-Reduction of
                                      GW Exposure      GW Exposure
                                        and GW         and GW Pump
                                       Treatment        and Treat
Overall Protection
Compliance w/ ARARs
Long- Term
Effectiveness
Reduction of T/M/V
Short-Term
Effectiveness
0
0
0

0
5

1
0
1

0
4

4
4
4

5
3

5
5
5

5
3

5
5
5

5
3

$140,055
$990,225
                                                         33,873,299
$9,894,308
$6,562,349
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SECTION 11.       THE SEIiECTED REMEDY

    Based upon consideration of the requirements of CERCLA, the NCP, the detailed analysis of
alternatives and public and state comments, EPA has selected Alternative 3 as the groundwater
remedy for this Site. The remedy includes connecting all homes, churches and businesses in the
"Davis Park Road Site Area" as depicted in Figure 1-1 of this document to the City of Gastonia
public water supply, optional installation of granulated carbon filters on private wells with
operation and maintenance of the filter for one year with a filter replacement after the first
year of operation; and a Natural Attenuation study followed by monitored Natural Attenuation of
the bedrock aguifer groundwater plume. Groundwater monitoring will be conducted on a quarterly
basis for three years and annually for the next 27 years. The first year of quarterly sampling
will be augmented to include parameters necessary to complete the Natural Attenuation Study.
Groundwater will be analyzed for VOCs as well as necessary groundwater geochemical data,
hydrogeologic parameters, and other necessary information to complete the Natural Attenuation
Study. The Natural Attenuation study will be designed during the Remedial Design phase and will
be conducted in accordance with Region IVs Draft Region 4 Approach to Natural Attenuation of
Chlorinated Solvents. For the first year, these additional samples will be collected, and
combined with data collected during the RI, and will comprise the Natural Attenuation Study. The
conclusions of the study will be published in a report by EPA.

    At the completion of this remedy, the risk associated with this Site has been calculated to
be within the accepted risk range determined to be protective of human health and the
environment. The remedy is expected to take 7 years. The total present worth of the selected
remedy is $3,873299. Tables 11-1 and 11-2 provide a detailed cost estimate for the chosen
remedy.

    In the event that data collected during the Natural Attenuation study cannot substantiate
the occurrence of natural attenuation, a contingency remedy, Alternative 5, will be implemented.
Alternative 5 has all of the components of reduction of exposure to contaminated groundwater
described in Alternative 3, plus adds active treatment of the contaminated bedrock aquifer
groundwater plume using pump and treat. The total present worth of this remedy is $6,562,349. It
is anticipated that this decision will be made within 3 years and, if appropriate, will be
documented by an amendment to this Record of Decision.
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Table Number: 11-1                                        PRESENT WORTH CAPITAL COST
Alternative No.3 -Reduction of GW Exposure plus Monitored Natural Attenuation
Site Name: Davis Park Road TCE Site
Site Location: Gastonia, NC

         ITEM DESCRIPTION                  QUANTITY

TREATABILITY STUDY                                 1

NATURAL ATTENUATION STUDY                          1

CITY WATER CONNECTIONS
  Istallation/75 residents                5,500 feet
  Design specifications, regulatory
approval, permits  (20%)

WELLHEAD TREATMENT
 Installation per residence  (includes             75
carbon UV light and Fe filter)
 GAG filter replacement after 1 year              75
Discount Rate: 7%
Date: July 1998

    UNIT COST(S)

           Lump Sum

           Lump Sum


            85/foot
              7,550

                530
TOTAL COST DOLLARS

               $17,500

               $50,000


              $467,500

               $93,500


              $566,250

               $39,750
SUBTOTAL - CAPITAL COST

Five Year Review  (includes groundwater sampling)

PRESENT WORTH-FIVE YEAR REVIEWS

SUBTOTAL

ADMINISTRATION  (15%)

CONTINGENCY  (25%)

TOTAL CAPITAL COST

PRESENT WORTH O&M COST

TOTAL PRESENT WORTH COST
                                     31,234,500

                                        $27,500

                                        $97,430

                                     $1,331,930

                                       $199,790

                                        382,930

                                     $1,914,650

                                     $1,958,649

                                     $3,873,299
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Table Number: 11-2                           REMEDIAL ACTION OPERATION COST
Alternative No.3 -Reduction of GW Exposure plus Monitored Natural Attenuation
Site Name: Davis Park Road TCE Site                       Discount Rate: 7%
Site Location: Gastonia, NC                               Date: July 1998
  ITEM DESCRIPTION
                               ANNUAL
                              QUANTITY
                 UNIT COST
                    ($)
                TOTAL COST PER
                     YEAR
WELL MAINTENANCE
                                                  lump sum
                                           $27,000
GW Monitoring
Quarterly
    VOC Analysis
    Labor(sampling)
    Report Preparation

Annual
    VOC Analysis
    Labor(sampling)
    Report Preparation

WELLHEAD TREAT
   Labor (6% Of Capital)
   Maintenance  (2% of
 capital)
   Monitoring of effluent
  (guarterly for 1 year)

GROUNDWATER
MODELING
72
4
4
21
1
1

$125/sample
$2,400/event
$2,500/event
$125/sample
$2,400/event
$2,500/event
lump sum
lump sum
$9,000
$9, 600
$10,000
$2, 625
$2,400
$2,500
$114,879
$38,293
75X4=300
300/sample
                      $5,000
$90,000
                          $5,000
TOTAL PRESENT WORTH O&M COSTS - $1,958,649
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    Performance Standards

    The goal of this remedial action is to restore the groundwater to its beneficial use. Based
on information obtained during the RI,  and the analysis of all remedial alternatives, EPA and
the State of North Carolina believe that the selected remedy will be able to achieve this goal.

    Groundwater shall be treated until the following performance standards are attained
throughout the contaminant plumes:

           Contaminant                           Remediation Level       Risk Level

           Trichloroethene                           2.8 ug/1            1E-06

           Tetrachloroethene                           1 ug/1            1E-06

           1,1-dichoroethene                           lug/1             IE-04

           Chloroform                                  1 ug/1            1E-06

           Methyl-tert-butyl ether                   200 ug/1            HI=1

         Hazard Index (HI) - Relates to non-cancer risks
         1E-06 Risk Level - Probability for carcinogenic effects
         (See Section 6 of this document for an explanation of HI and Risk Levels)
         ug/1 - micrograms per liter
    If it is determined that certain portions of the aguifer cannot be restored to their
beneficial use, all of the following measures involving long-term management may occur, for an
indefinite period of time, as a modification of the existing system:

      a)  engineering controls such as physical barriers, or long-term gradient control provided
         by low level pumping,  as contaminant measure;

      b)  performance standards may be waived for the cleanup of those portions of the aguifer
         based on the technical impracticability of achieving further contaminant reduction;

      c)  institutional controls may be provided/maintained to restrict access to those portions
         of the aguifer which remain above remediation levels;

      d)  continued monitoring of specified wells; and

      e)  periodic reevaluation of remedial technologies for groundwater restoration.

    The decision to invoke any or all of these measures may be made during a periodic review of
the remedial action, which will occur at 5 year intervals in accordance with CERCLA Section
121(c).

    The remedial actions shall comply with all ARARs  (See Section 7).

    Additional Sampling Reguirements

    Additional groundwater sampling shall be conducted to further define the extent of
contamination. Specifically, the following shall be obtained at a minimum:

       •       Additional,  limited characterization of the southerly and southwesterly extents  of
              VOC contamination in the bedrock aguifer along suspected fracture zones;  and

       •       Periodic private  well sampling to determine if any of the residents'  wells exceed
              the Emergency  Response action level of 70 ug/1 for PCE.

SECTION 12.         DOCUMENTATION OF SIGNIFICANT CHANGE
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    CERCLA Section 117(b) requires an explanation of significant change from the preferred
alternative presented in the Proposed Plan dated July 27, 1998. In the proposed plan,
Alternative 3 was chosen for groundwater at the Davis Park Road Site. Alternative 5 is the
contingency remedy. EPA reviewed all written and verbal comments submitted during the public
comment period. It was determined that no significant changes to the remedy, as originally
identified in the Proposed Plan, were necessary.
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                                             Appendix A

                           Responsiveness Summary for the Record of Decision
                          Davis Park Road TCE Site, Gastonia, North Carolina

    Response to Stakeholder Comments

A number of individual citizens who attended the public meeting on the Proposed Plan on July 28,
1998 asked if their well had been sampled and what the results were.

During the Proposed Plan public meeting EPA attempted to provide information to individual
residents on the results of historic sampling of their private or community well if that
information was available, EPA will prepare a mailing to each resident presenting the results of
any sampling conducted by EPA on their well.

In addition, if a resident reguests that their private well be sampled, EPA will determine if
the well can be sampled during the monitoring program for the Davis Park Road Site or whether to
refer the resident to the Gaston County Department of Health for their consideration.

What is the extent of the City Water connections which will be offered to residents impacted by
the Davis Park Road Site, and when will those connections be made?

EPA will determine as part of the Remedial Design for the Site which residents have been,  or may
potentially become, impacted by contaminated groundwater. The extension of the City Water line
will be determined as EPA completes it's Remedial Design. It is anticipated that the Remedial
Design will take approximately one year to complete. Availability of Remedial Action funding
through the Superfund is dependent on the relevant risks of the Davis Park Road Site compared to
other Sites Nationally which are candidates for Remedial Action funding that same fiscal year.
EPA will begin the Remedial Action, including the extension of City Water lines, as soon as the
Remedial Design is complete and Remedial Action funding is available.

Private Residents will be allowed to keep their current well, however, if City Water is
provided, there can be no interconnection of the two systems. EPA, as part of the Remedial
Action, will provide an activated carbon filter system to those residents who are impacted by
the Site and reguest a filter be installed on their private well.

Why was the current City Water line extended only as far as it is, and if I paid to connect to
the City Water in the past will I be reimbursed by EPA for my costs?

The Current City Water line in the area impacted by the Davis Park Road Site was installed by
the City of Gastonia because of a petition by residents. The connections were made by a special
assessment process, and was extended to the limits of the petition.

EPA is currently looking into the ability to reimburse citizens who have been impacted by the
Davis Park Road Site, and have paid on their own to connect to the City water system because of
concerns surrounding the contamination at the Site.

Is the property at 2307 Davis Park Road the only source of groundwater contamination in the
area?

EPA conducted an additional source investigation during the Remedial Investigation. The Remedial
Investigation findings concluded that contaminants detected in groundwater may be a result of
earlier soil contamination detected at 2307 Davis Park Road, however, no continued source of
contamination was detected in soils on this property. EPA has not been able to determine what
specific housekeeping practices or past spills may have resulted in the past detections of soil
contamination or in the current groundwater contamination, or when the contamination first
started. No source of the presumptive evidence of petroleum products detected at very low levels
in limited groundwater samples has been determined. However, with the exception of
Methyl-tert-butyl ether which may be related to petroleum type compounds, none of these
contaminants are contaminants of concern for the Site.

EPA will continue to monitor groundwater in the area of the site during the Remedial Design and
Remedial Action. If EPA determines through groundwater analysis that there may be a new source
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of contamination, EPA will attempt to locate that source.

Based on the composition of the bedrock aquifer system,  is the primary Natural Attenuation
process dilution/dispersion or biodegradation of contamination?

During the Remedial Investigation, EPA collected samples and conducted modeling efforts to
determine if Natural Attenuation factors were acting to reduce the contamination in the
groundwater at the Site. Based on this information,  EPA has determined that the contamination in
the bedrock aguifer is most likely discharging to Blackwood Creek, and that contaminant
reduction is primarily through the dispersion/dilution of contaminants. However, because some
degradation products of both TCE and PCE have been detected, EPA does believe that some in-situ
biodegradation is occurring. EPA will attempt to more conclusively determine, as part of the
Remedial Design,  whether Natural Attenuation of Site contaminants in the bedrock aguifer is
occurring at the Site. EPA intends to publish it's findings in a report.
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