United States Office*
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-93/145
September 1993
SERA Superfund
Record of Decision:
Para Chem Southern, SC
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R04-93/145
3. Recipient's Accession No.
Title and Subtitle
SUPERFUND RECORD OF DECISION
Para Chem Southern, SC
First Remedial Action - Final
5. Report Oat*
09/27/93
7. Authors)
8. Performing Organization Rapt No.
9. Performing Organization Nam* and Address
10 Project Taskwork Unit No.
11. Contract(C)orGrant(G)No.
12. Sponsoring Organization Nam* and Address
U.S. Environmental Protection Agency
401 M Street, S.w.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/800
14.
15. Supplementary Notes
PB94-964034
16. Abstract (Limit: 200 words)
The 100-acre Para Chem Southern site is a manufacturing plant located in Greenville
County, South Carolina. Land use in the area is predominantly industrial to the
southwest and is undeveloped and heavily forested elsewhere. An elementary and middle
school are located approximately one mile east of the site, and a hospital and high
school are located approximately one mile to the west. Residents obtain their drinking
water supply from the city. Beginning in 1965, Para Chem Southern used the site to
produce acrylic polymers, thickeners, latex coatings, and adhesives for a variety of
consumer and industrial applications. Three concrete settling tanks were used to
collect and treat wastewater from the manufacturing plant, which was discharged into
one of two lagoons built by Para Chem Southern as part of their past wastewater
treatment system. In 1977, after a biological waste treatment plant was built, the
concrete settling tanks were eventually taken out of service. Treated wastewater,
which was controlled by a NPDES Permit, flowed from lagoon 1 to lagoon 2, and the
effluent from lagoon 2 flowed through a catch basin onto the ground, where it
eventually reached the stream at the rear of the property. With construction of the
wastewater treatment plant the water first went through the water treatment plant, and
then to lagoon 1. In 1981, a fire resulted in the release of latex, foam, and water
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Para Chem Southern, SC
First Remedial Action - Final
Contaminated Media: soil, debris, sludge, gw
Key Contaminants: VOCs (benzene, PCE* TCE, toluene, xylenes)
b. Identifiers/Open-Ended Terms
c. COSATI Reid/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (TM* P»9«)
None
21. No. of Pages
62
22. Price
(See ANSJ-Z39.18)
Set Instructions on Rtvint
OPTIONAL FORM 272 (4-77)
(Formerly NT1S-3S)
Department of Commerce
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EPA/ROD/R04-93/145
Para Chem Southern, SC
First Remedial Action - Final
Abstract (Continued)
into a drainage channel. In 1984, lagoon 1 was closed, and a pipeline was constructed to
direct the effluent to lagoon 2. In 1985, two spills of ethyl acrylate occurred during
plant operations at a tank farm west of the plant production area. As a result, a small
amount of ethyl acrylate discharged into an adjacent storm drainage ditch. In 1986, the
State ordered Para Chem Southern to investigate environmental conditions at the site and
assess ground water quality. In 1987, Para Chem Southern removed 3,000 tons of drums,
waste materials, soil, and debris from four disposal areas, and performed geophysical
surveys to identify waste locations. In 1988, an interim remedy addressed contaminated
ground water and included the installation of three recovery wells, the treatment of
recovered ground water by air stripping, offsite discharge to a POTW, and the collection
of surface water and sediment samples. This ROD addresses a first and final action for
contaminated subsurface sludge/soil that will prevent further leaching of contaminants to
ground water. The primary contaminants of concern affecting the soil, debris, sludge, and
ground water are VOCs, including benzene, PCE, TCE, toluene, and xylenes.
The selected remedial action for this site includes excavating and treating approximately
200 yd^ of contaminated subsurface soil and/or sludge onsite using ex-situ biological
treatment; removing and sampling the in-ground concrete tank to evaluate proper disposal
options; filling the excavated concrete basin with clean soil and revegetating the area;
disposing of the non-biodegradable portions of the sludge and adjacent soil to a RCRA
approved facility; pretreating onsite with stabilization to meet land disposal
restrictions, if necessary; extracting and treating contaminated ground water onsite using
air stripping to remove organic contaminants; pretreating and discharging the treated
ground water offsite to a POTW, if necessary; monitoring ground water and surface water;
and implementing institutional controls, including deed, ground water, and land use
restrictions, and site access restrictions. The estimated present worth cost for this
remedial action is $5,498,000, which includes an estimated annual O&M cost of $281,000 for
30 years.
PERFORMANCE STANDARDS OR GOALS:
Subsurface soil and sludge cleanup goals are based on results of a leaching model using
site-specific information. Chemical-specific cleanup goals include .acetone 4,687 mg/kg;
1,1-DCE 2.6 mg/kg; 1,2-DCE 446 mg/kg; PCE 0.446 mg/kg; 1,1,1-TCA 10.5 mg/kg; TCE 1.7
mg/kg; and toluene 122.7 mg/kg. Ground water cleanup goals are based on the baseline risk
assessment, health based goals, and SDWA MCLs and MCLGs. Chemical-specific ground water
cleanup goals include acetone 0.52 mg/1; aluminum 0.05 mg/1; benzene 0.005 mg/1;
2-butanone 0.6 mg/1; chloroform 0.0005 mg/1; 1,1-DCA 0.78 mg/1; 1,2-DCA 0.005 mg/1; 1,1-
DCE 0.007 mg/1; 1,2-DCE 0.07 mg/1; manganese 0.05 mg/1; methylene chloride 0.005 mg/1; PCE
0.005 mg/1; 1,1,2-TCA 0.003 mg/1; 1,1,1-TCE 0.2 mg/1; TCE 0.005 mg/1; toluene 1 mg/1;
xylenes (total) 10 mg/1; and zinc 5 mg/1.
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RECORD OP DECISION
SUMMARY OP REMEDIAL ALTERNATIVE SELECTION
PARA.-CHEM SOOTHERHf IK. SUPERPUMD SITE
SIXPSOBVILLE, GRBEHVILLE COUNT!
SOUTH CAROLINA.
|}j g
U.S. EMVUtOMMKCITAL MtUTECTlOJI ai-E«iM'T
REGION IV
ATLANTA, GEORGIA
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-x . DKCLARATIOH FOR TBS RECORD or DBCISZOH
SITE NAME AHP LQgXTTQH
Para-Chat Southern, Inc.
Simpsonville, Greenville County/ South Carolina
STATEMEUT OP BASIS AND PURPOSE
This decision document present* the selected remedial action for the Para-
Chem Southern/ Inc. Superfund Site (the Site) in Simpsonville, South
Carolina/ which was chosen in accordance with the Comprehensive
Environmental Response/ Compensation, and Liability Act of 1980, as amended
by the Superfund Amendments and Reauthorization Act of 1986 (SARA), 42
D.S.C S 9601 et aeg.. and, to the extent practicable/ the National Oil and
Hazardous Substances Contingency Plan (NCP), 40 C.P.R. Part 300 et gag.
This decision is based on the administrative record file for this Site.
The State of South Carolina concurs with the selected remedy.
ASSESSMENT OP THE SITB
Actual or threatened releases of hazardous substances from this Site, if
•»t addressed by implementing the response action selected in this Record
Decision (ROD)/ may present an imminent and substantial endangerment to
,-tolic health/ welfare, or the environment.
DESCRIPTION Of THE SELECTED REMEDY
This remedial action addresses on-Site and off-Site groundwater
contamination, the principal threat at this Site? as well as on-Site sludge
contamination.
The major components of the selected remedy includes
Q Excavation of contaminated sludge and subsurface soil,
with verification sampling;
0 Biological treatment of sludge. Treatability studies may be
performed if deemed necessary by EPA to evaluate the effectiveness of
this process;
a Transportation of the non-biodegradable portions of the
sludge and adjacent soils to an approved facility/ and treatment
of the sludge and soils, if necessary, to comply with land disposal
restrictions (LDRs);
Q Extraction of contaminated groundwater;
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0 Treatment of contaminated groundwater using air stripping to remove
organic contaminant*. Additional pretreataent will be par formed, if
necessary, to allow for discharge of the treated groundwater to a
local publicly-owned treatment works (POTW);
STATUTORY DETEBMIMATIOHS
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 utilises permanent solutions and alternative treatment
technology to the »«MT«M» extent practicable for this Site and satisfies
the statutory preference for remedies that employ treatment that reduces
toxicity, mobility and/or volume as a principle element.
This selected remedy will result in contaminated groundwater remaining on-
Site above health-based levels until remedy implementation is complete.
Therefore, a five (5) year review will be conducted after initiation of
remedial action to insure that the remedy continues to provide adequate
protection of human health and the environment.
Patrick M. Tobin Date
* -ting Regional Administrator
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1.0 SITE LOCATION AND DESCRIPTION . 1
1.1 Site Description 1
1.2 Sit* Topography and Drainage 1
1.3 Meteorology 4
2.0 SITE BISTORT AMD BHPORCEMBHT ACTIVITIES 4
2.1 Sit* History 4
2.2 Enforcement Activities » . . 6
3.0 HIGHLIGHTS OP COMMUNITY PARTICIPATION .... . 6
4.0 SCOPE AND ROLE OP THIS ACTION WITHIH SITS STRATEGY 7
5.0 SUMMARY OP SITE CHARACTERISTICS 7
5.1 Geologic and Hydrogeologic Setting 7
5.2 Remote Sensing Investigation 8
5.1.3 Hydrogeology 11
5.2 Nature and Extent of Contamination 11
5.2.1 Surface Soil and Subsurface Soils/Sludge 12
5.2.2 Groundwater 14
5.2.3 Surface Water and Sediment 15
6.0 SUMMARY OP SITE RISKS 15
6.1 Human Health Risks 15
6.1.1 Contaminants of Concern 15
6.1.2 Exposure Assessment 16
6.1.3 Toxicity Assessment -of Contaminants 22
6.1.4 Risk Characterization 24
6.2 Environmental Risks 28
7.0 REMEDIAL ALTERNATIVES 29
7.1 Description of Remedial Alternatives 30
7.2.1 Alternative It No Action . . 42
7.2.2 Alternative 2s Institutional Controls . . 42
7.2.3 Alternative 3s Groundwater Extraction 6 Treatment . . 43
7.2.4 Alternative 4s Capping of Sludge with Groundwater
Treatment 44
7.2.5 Alternative 5s Excavation of Sludge with Groundwater
Treatment 45
8.0 SUMMARY OP COMPARATIVE ANALYSIS OP ALTERNATIVES 46
8.1 Threshold Criteria 46
8.2 Primary Balancing Criteria * 47
8.3 Modifying Criteria 49
9.0 THE SELECTED REMEDY . 49
9.1 Source Control . 50
9.1.1 Sludge/Soil Performance Standards 51
9.1.2 Excavation and Treatment Standards 51
> 9.1.3' Applicable or Relevant and Appropriate Requirements
v (ARARS) . 52
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9.2 Groundwater Remediation 53
9.2.1 Groundwater Performance Standards 54
9.2.3 Applicable or Relevant and Appropriate Requirement*
(ARARs) 56
9.4 Compliance Testing 58
9.5 Monitor Site Groundwater and Surface Water 58
10.0 STATUTORY DETERMINATIONS 59
APPENDICES
APPENDIX A - RESPONSIVENESS SUMMARY
APPENDIX B - STATE LETTER OF CONCURRENCE
APPENDIX C - PROPOSED PLAN
APPENDIX D - PUBLIC NOTICE OF PUBLIC COMMENT PERIOD
APPENDIX B - PROPOSED PLAN PUBLIC MEETING SIGN-IN SHEET
APPENDIX F - OFFICIAL TRANSCRIPT OF PROPOSED PLAN PUBLIC MEETING
LIST OF PLATES PAGE
Site Location Map 2
Base Map 3
Phase I Location Map 9
Phase II Location Map 10
Subsurface Waste-water Sludge 13
LIST OF TABLES
Summary of Contaminants of Concern... 18
Screening of Remedial Technologies 25
Final Remedial Alternatives 34
Remedial Alternatives Cost ....42
Sludge/Soil Performance Standards 52
Groundwater Performance Standards 54
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1.0 SITE LOCATION AMD DESCRIPTION
The Para-Chen Southern, Inc. site (Site) is located In Greenville County,
South Carolina, between Simpsonville and Fountain Inn (Figure 1). The Site
is approximately 100 acre* of property upon which a manufacturing plant is
located. The plant is owned and operated by Para-Chem Southern, Inc.
(Para-Chem) and is used to produce acrylic polymers, thickeners, latex
coatings, and adhesive* for a variety of consumer and industrial
applications. The plant has been in operation since 1965 and currently
employs approximately 150 people.
1.1 Site Description
The Site is located southeast of Simpsonville in Greenville ounty, South
Carolina. The topography at and near the Site consists of c .itly rolling
hills. Land use southwest of the Site is primarily industrial. Elsewhere,
the land adjacent to the Site is undeveloped. The undeveloped land is
generally heavily forested. An elementary and middle school are located
approximately one mile east of the Site and a hospital and high school are
located approximately one mile west.
Para-Chea acquired the property comprising the Site in four parcels (Plate
*-l). The original parcel was purchased in 1964 and contains the main
:ility and outbuildings. The second and third parcels were acquired in
.72 and 1973. The fourth parcel was added in 1990 after an exchange of
land between Para-Chen and the owner.of the adjacent property to the north
of the Site. Prior to Para-Chem's purchase of the Site, the property was
used for agricultural purposes, primarily cotton and timber farming.
The Greenville City water system serves the majority of aroa residents.
Areas to the north and northeast of Para-Chem which are not serviced by
this system obtain water from both private and community wells.
1.2 Site Topography and Drainage
The Site is a grassy field with several paved parking lots and on-Site
building structures. Surface elevations at the Site decrease toward the
northeast, with slopes ranging from 5 to 10 percent. Surface drainage at
the Site occurs by overland flow and through several gullies leading
northeast towards the unnamed stream. One of the gullies originates north
of Lagoon Ho. 2 and receives a discharge of non-contact cooling water
before intersecting the unnamed stream. Two (2) smaller gullies originate
south of Lagoon NO. 1 and trend to the wet-, toward the stream. These
smaller gullies are the source of intermittent streams, with flow limited
to the fall and winter seasons. These tributaries discharge into Durbin
Creek (see Plate 1-1)
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SITE LOCATION MAP
SCALE r-axxr
PARA-OEM SOUTVERN. NC
OfCENVUJE.SC
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-.3 Meteorplooy
The temperature rises to 90*P or above on almost half of the days during
the summer months, but usually falls to 70*P or lower during the night.
Winters are moderate, with the temperature remaining below freezing
throughput the daylight hours only three (3) to four (4) times during a
normal year. The mean annual temperature for this area is 60*F. Rainfall
is .usually abundant and spread fairly evenly throughout the year. The
average annual precipitation for this area is 51 inches per year. The
prevailing wind directions are generally northeast during the fall and
winter, .and southwest during the spring and summer months.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 Site History
As part of its manufacturing operations, Para-Chem built and used a series
of concrete settling basins and two lagoons as part of their past
wastewater treatment system (Plate 2-1). Effluent from the lagoons was
discharged to a receiving stream, originating on-Site, under National
Pollutant Discharge Elimination System (NPDBS) Permit SC0001244, issued by
the State of South Carolina on November 13, 1984.
~*-e concrete settling tanks were installed in 1965. They consisted of
tee (3) concrete tanks, rectangular in size, each with a capacity of 1500
v«llons. The purpose of the settling tanks was to collect and treat
wastewater froa the manufacturing plant. Wastewater would flow through a
concrete trench to the tanks which were lined up end to end in series. The
first tank contained a mixer and alum was added to aid precipitation. The
solids settled in the second tank and the liquid overflowed into the third
tank for additional settling time. Water from the last tank flowed into
Lagoon No. 1.
Sludge from the tanks was occasionally spread in a drying area that fozaed
a shallow pond approximately 50 feet x 50 feet at the rear of Lagoon No. 1.
The dried material was eventually spread over the area immediately to the
east of the pond.
In 1977, a biological waste treatment plant was built. Agitators were
removed from the concrete settling tanks and eventually the tanks were
taken out of service. Closure of the tanks consisted of leaving the sludge
in place and topping the tanks with soil. A half pipe extension was added
to the trench to allow wastes to bypass the settling tanks to the waste
treatment plant. This eliminated the use of the settling tanks.
Lagoon f 1 was constructed in conjunction with the concrete settling tanks
during plant startup in 1965. This lagoon held approximately 1,000,000
gallons of wastewater at any one time. Water levels wer? maintained by
evaporation and seepage to groundwater. As the manufacturing facilities
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—ponded, more wastewater was produced. This eventually caused Lagoon Mo.
1 to reach »««*qn«» capacity and necessitated the construction of Lagoon Mo.
2 •
Lagoon #1 was cleaned out on two occasions using a drag line and bucket.
Material was spread on the ground around the periphery of the lagoon and
along the swale west of Lagoon Mo. 2. Although sludge accumulated at the
upper end near the influent pipe, the average sludge depth in the lagoon
was three (3) to four (4) feet. Approximately 2000 yards of sludge was
reaoved during each cleaning cycle. The sludge consisted of polymerized
latex, clay and calcium carbonate from compounding. The material dried
readily and was eventually covered and seeded.
Treated wastewater from Lagoon No. 1 flowed through an underground pipe to
Lagoon Mo. 2. The effluent from Lagoon Mo. 2 flowed through a catch basin
and onto the ground where it eventually reached the stream at the rear of
the property. The discharge was controlled by the MPDES Permit. With the
construction of the waste treatment plant in 1977, wastewater first went
through the waste treatment plant, and then to Lagoon No. 1 prior to
discharge. Zn 1984 Lagoon Mo. 1 was closed and a pipeline was constructed
to direct the effluent to Lagoon #2.
During the closure of Lagoon fl, it was discovered that the sludge was
sitting on a clay layer. Both Para-Chem and South Carolina Department of
—»alth and Environmental Control (SCDHBC) decided at that time that it was
Jy necessary to cover the surface with clay. A gravel and asphalt
...arking lot was located on top .of the closed lagoon. When the plant
effluent was tied in to Western Carolina Regional Sewer Authority in 1987,
it was decided to close Lagoon Mo. 2 as well. Sludge from Lagoon Mo. 2
was removed and disposed of in a local landfill with SCDHBC approval.
Two (2) spills of ethyl acrylate totaling 3,515 gallons occurred on January
28, 1985, and October 1, 1985, during plant operations at a tank farm west
of the plant production area. The spills occurred within an earthen dike
containment area. However, a small amount of ethyl acrylate discharged
into an adjacent storm drainage ditch. The spills were contained on Para-
Chem property. A plant fire on March 16, 1981, resulted in the release of
approximately 5,000 gallons of latex material, foam, and water into «
drainage channel which leads to a stream which flows to the north across
the Site.
A package wastewater treatment system is now in operation at the Site.
Treated process wastewater has been discharged to Western Carolina Regional
Sewer System (WCRSA) since April 1988. Para-Chem is authorised to
discharge non-contact process water under a MPDES Permit at a point source
originating on Para-Chem property. The manufacturing portion of the
facility operates with an air emissions treatment system approved by
SCDHEC.
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. 2 BnforCflMflt Activities
On February 27, 1985, Para-Cham notified US EPA and SCDHBC of three areas
on the Para-Cheat Sit* where waste* war* thought to have been buried between
1975 and 1979. On February 27, 1986, Para-Chem entered into Consent Order
86-17-W, SW with SCDHBC requiring Para-Chen to investigate environmental
conditions at the Site. These investigations consisted of geophysical
surveys, drilling and well installation, soil and water sampling, and waste
removals.
Approximately 3,000 tons of drums, waste materials, soil, and debris were
removed from four former disposal areas in 1987. Geophysical surveys were
performed to identify the extent of the former disposal areas, and to
confirm removal of buried materials.
A groundwater quality assessment program was initiated in 1985 and
continued through 1991, including the installation of monitoring wells.
Laboratory results of groundwater samples have been submitted quarterly to
SCDHBC since March 1989.
Interim remediation of groundwater was initiated with the installation of
three recovery wells in 1988. A total of 14 additional recovery wells were
added to the system in two subsequent phases. Recovered groundwater is
treated at an air stripper prior to discharge to the POTW.
litional activities included collection of stream surface water, stream
. .idiaant, and subsurface sediment samples.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Interviews with residents were conducted in January 1992. A Community
Relations Plan was developed and an information repository was established
at the Fountain Inn Branch of the Greenville County Library in March 1992.
A fact sheet announcing the start of the RI/FS was issued in early January
1992. On January 21, 1992, EPA held a public meeting at Bryson Middle
School to inform the public of the RI/FS process. The meeting was attended
by more than 40 citizens and covered by the local newspaper (Greenville
News) and one television station. BPA's presentation to the public
included information on how to participate in the investigation and remedy
selection process under Super fund. RZ field work was initiated in April
1992, and continued throughout the month of May 1992. Additional field
work was conducted from July 1992 through December 1992. The final
Remedial Investigation/Feasibility Study Report was released to the public
and placed in the information repository on June 21, 1993.
Following completion of the RI and the FS, the proposed plan fact sheets
were released on June 18, 1993. An advertisement was published in the
local newspapers on June 19, 1993, informing the public of the proposed
nlan, public meeting, and the public comment period which extended from
\e 21, 1993,«%o July 21, 1993.
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-»e proposed plan public mating was held on June 29, 1993, to present the
Agency's selection of preferred alternatives for addressing soil and
groundwater contamination at the Site. Representatives from SCOHBC were
present at this public meeting. Public comments and questions are
documented in the Responsiveness Summary, Appendix A.
4.0 SCOPE AMD ROLE OP THIS ACTION WITHIN SITE STRATEGY
The purpose of the remedial alternative selected in this ROD is to reduce
future risks at this Site. The remedial action for contaminated subsurface
sludge/soil will remove future health threats by preventing leaching of the
contaminants to groundwater. The groundwater remedial action will remove
future risks posed by potential usage of contaminated groundwater.
Additional activities will include monitoring the threat to surface water
in Dnrbin Creek and the unnamed tributaries in addition to further
characterization of the five (5) areas identified during the soil gas
survey. This is the only ROD contemplated for this Site.
5.0 SUMMARY OP SITE CHARACTERISTICS
The RI investigated the nature and extent of contamination on and near the
Site, and defined the potential risks to human health and the environment
*sed by the Site. A total of thirty nine (39) soil samples, thirty three
)) groundwater samples, six (6) surface water samples, and four (4)
.odlment samples were collected during the RI. The main portion of the RI
(Phase I) was conducted from April 19-92 through June 1992, followed by
additional bedrock well installation, groundwater sampling and surface
water sampling between October and December 1992 (Phase II). On-Site
locations of soil borings, soil samples, and monitor wells sampled during
Phase I are shown in Plate 5-1. The sampling locations for Phase II are
presented in Plate 5-2.
•S.I Geolocrc
This Site is situated in the Piedmont physiographic province of South
Carolina. The Piedmont province is a broad plateau ranging in elevation
from 400 to 1200 feet above sea level. The geology of the province
consists of highly metamorphosed rocks, primarily gneiss and schists,
intruded by igneous rocks. The metamorphic/ igneous rocks consist of the
following assemblages s granite, biotite schist, granite gneiss, gneiss-
schist complex, mica-granite gneiss, and diabase dikes . The bedrock is
overlain by a layer of saprolite, slope wash deposits, and alluvial fill
material of variable thickness .
The plateau region is dissected by streams which have developed a dendritic
drainage pattern. This drainage pattern is characteristic of rock that is
resistant to erosion. Stream flow in the province is predominantly to the
•hi:' \theast. Major streams in the province occur in valley bottoms upon a
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8
....prolite or slope wash deposit base. Tributaries flow from ridge areas in
an irregular pattern to these aajor streams.
The predominant soils at the Site are classified as Cecil Series and
consist of sandy and clayey loans. These are underlain by sands and clays
within the saprolite, and a partially weathered rock zone, which is
underlain by bedrock.
S,2 Ttefflote Sensing Investigation
The potential for fractured bedrock at the Site was addressed through the
use of two (2) remote sensing techniques. Separate subcontractors were
retained to perfora a Fracture Trace Analysis (FTA) and Very-Low Frequency
(VLF) geophysical survey. The results of the study indicate that there are
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11
, discernable large seal* fracture traces that affect the Site. The only
identifiable fracture trace occurs approximately three Biles southwest of
the Site. A VLF geophysical survey was conducted at the Site by AGE Co. of
Austin, Texas. The survey began on May 4, 1992, but was not completed
until May 22 due to bad weather. The VLF geophysical survey was conducted
within the areas that contain affected groundwater. The purpose of the
survey was to nap vertical or steeply-dipping fracture systems, if present,
within bedrock. The VLF survey was only partially successful. Several
anomalous areas were identified, however, the cause of the anomalies could
not be identified with certainty. The results of the VLF survey were taken
into consideration, along with other criteria, for selecting the Phase IX
bedrock drilling locations.
5.1.3
The groundwater investigations which were conducted as part of the RZ were
primarily concerned with groundwater quality. The Phase 1 RI included the
collection of groundwater samples from thirteen (13) existing monitoring
wells shown in Plate 5-1. Groundwater samples were also collected from the
fractured bedrock during packer testa conducted as part of the Phase 2 RZ
(Plate 5-2). Characteristics of the saprolite, including hydraulic
conductivity, groundwater flow rate and direction, and vertical gradients,
were addressed during previous investigations. A summary of the these "
"ndings is included in Appendix A of the RI.
.. direct bedrock investigation was conducted consisting of rock core
drilling at eight (8) boring locations and a field check for outcrops of
bedrock. The locations of borings B-l through B-8 are shown on Plate 5-2.
Packer testing conducted at borings B-l through B-8 yielded data which was
used to calculate the hydraulic conductivity of the tested interval.
Hydraulic conductivity values ranged from 9 x 10~* cm/sec to 7 x 10"*
cm/ sec.
5.2 ature Bactent of
Environmental contamination at the Site can be summarised as follows*
1. Subsurface sludge contains greatly elevated levels of several
volatile organic compounds (VOCs) and inorganic contaminants.
2. Groundwater is contaminated with organic contaminants at levels
ranging from the detection limit to 110,000 ug/1, and by several
inorganic contaminants•
3. Contamination is present in the on-Site tributaries of Big Dnrbin
Creek. Three (3) VOCs, 1,1-Dichloroethene, 1,1,1-Trichloroethane,
and Tetrahydrofuran, are present in the creek at levels of 2.0 ug/1,
2.0 ug/1, and 4.0 ug/1, respectively.
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12
.2.1 Surface Soil *\nA Subsuirface Soils/Sludge
Soil sampling efforts were designed to evaluate the effectiveness of the
previous waste removal activities and to investigate other known and
suspected disposal areas. A total of thirty nine (39) soil camples were
collected daring the RI. Based upon historical information that included
waste disposal information, surface soil sampling was not evaluated as part
of this investigation. Plate 5-3 summarises the distribution of sludge as
it was encountered during the RZ.
Former Disposal Areas
Soil Samples were collected from disposal areas No. 1, 2, 3, and 4 (see
Plate 5-1). Trace levels of inorganic contaminants (copper, lead, sine,
chromium, and iron) were detected in areas Mo. 1, 2, and 3, but at levels
so low that they do not pose a health risk and will not migrate or leach
from the soil into groundwater. One of the samples (HA-13) collected from
disposal area No. 4 contained actual wastewater sludge from past plant
operations. The organic compounds 1,1,1-trichloroethane, 1,1-
dichloroethane, tetrachloroethane, butylbenzylphthalate, and di-n- .
butylphthalate, were detected at disposal area No. 4. Of particular
concern is the 1,1,1-trichloroethane, which is present at levels requiring
sludge remediation.
Soil samples were collected from areas surrounding both Lagoon No. 1 and 2.
Trace levels of inorganic contaminants were detected, but at levels so low
that they do not pose a health risk and will not migrate or leach from the
soil into groundwater. Several organic contaminants are also present of
which one in particular, 1,1,1-trichloroethane, will require sludge
remediation for this area.
Above Ground Tank Area
The levels of the inorganic contaminants aluminum and copper, in addition
to the organic contaminant ethyl acrylate, were present, but at levels so
low that they do not pose a health risk and will not migrate or leach from
the.soil into groundwater.
Concrete Settling Basin
The soil samples detected both inorganic and organic contamination in the
settling basin. The concentrations of antimony and 1,1,1-trichloroethane
will require remediation of sludge from this area.
-------
14
Suspected Disposal Areas
Due to the large acreage presented for evaluation and the characteristics
of contamination present at this Site, a soil gas screening process was
used to investigate suspected disposal areas. Several confirmation samples
taken as a check to evaluate the effectiveness of this screening method
indicated that, for screening purposes, this particular soil gas technique
was acceptable . Based on this screening method, an area associated with
H-800 and G-800 (between lagoon No. 2 and disposal area No. 3) will require
remediation of sludge and/or soil. The soil gas survey revealed five (5)
additional areas that will require further characterization. These areas
are identified with the following soil gas stations!
• A-900 (east of maintenance shop area),
• D-800 (southwest of disposal area No. 4),
• H-400 (southeast of disposal area No. 2),
• F-300 & F-400 (northeast of production plant)
• D-500, D-643, E-500, B-600 (between production area and
lagoon No. 1)
litional sampling will be necessary during the remedial design to
itermine whether these areas warrant remediation.
5.2.2 Groundwater
Groundwater Cont*"11^ nation
The groundwater investigation was divided into two (2) phases. Phase I
concentrated on the upper portion of the aquifer (saprolite) while Phase II
focused on gronndwater conditions within the bedrock.
The Phase I sampling results indicated that groundwater within the
saprolite is contaminated with both inorganic and organic contaminants.
Three (3) of the inorganic and nine (9) of the organic concentrations
violated the maxima contaminant levels (MCLs) for those substances.
Phase II results revealed that organic contamination extended into the
bedrock at depths down to 100 feet below top of rock. Pour (4) of the
organic contaminants detected were present in concentrations in excess of
the MCL for those substances. In general, concentrations decreased with
depth within the bedrock.
Groundwater flow in the Saprolite is toward the northeast. Groundwater
contamination extends northeast to the property lines as evidenced by wells
:• :>>22, MW-22A,«HW-28, MW-28A, and MW-37 (see Plate 1-1). Contamination was
-------
IS
.so detected in two (2) off -Site wells (MW-39B and MH-44B), but at levels
below the MCLs.
5.2. rface Watag *
Four (4) surface water and sediment samples were initially collected from
the tributary at locations along the Site. Both inorganic (aluminum,
r.»nganese, iron, ar<* zinc) and organic (1,1-dichlorc-rhene, 1,1,1-
t ichlc 00 thane, a; tetrahydrofuran) contaminants were detected in the
surface water samples. However, the low concentrations of contaminants in
the stream do not warrant remediation at this time. The historical and
analytical results suggest that the aquifer is discharging contaminated
groundwater into the stream. This stream will be monitored to insure that
the contamination does not exceed an acceptable risk level and to verify
lat the groundwa*- discharge is acting as the source of contamination for
cnia stream.
Zinc was the only Anorganic contaminant present above detection limits for
the sediment samples. No organic compounds were detected above the
detection limits in either of the sediment samples.
6.0 SUMMARY OF SITE RISKS
;ual or threatened releases of hazardous substances from this Site, if
__.t addressed by implementing the response action selected in this Record
of Decision, may present an imminent .and substantial endangerment to public
welfare or the environment.
A Baseline Risk Assessment was conducted EPA to evaluate the risks
present at the Para-Chem Southern Site to .iuman health and the environment,
under present day conditions and under assumed future use conditions. The
Baseline Risk Assessment describes the risks to human health and the
environment which would result if the contamination present at the Site is
not cleaned up. This section of the ROD reports the results of the
baseline risk assessment conducted for this Site.
6.1 Hunan Health Risks
The human health risk assessment evaluated the nature and extent of the
threat to public health caused by the release or threatened release of
hazardous substances from the Site.
6.1.1 Contan|in*t*fc8 of Concent
The contaminated media at the 6ite are groundwater, surface water, sediment
and sludge/subsurface soil. Surface soils were not evaluated in the
remedial investigation. Historical information indicates that waste was
>>ced in subsurface trenches or burial areas.
-------
16
.e Site land use is currently industrial. Water for drinking at the
facility is supplied by the local water company. The Site is expected to
remain industrial in the future. Groundwater is currently used as a source
for drinking, showering, cooking, dish washing, laundering and gardening
for properties surrounding the Site.
Chemicals were included in the discussion of the Site risks if the results
of the risk assessment indicated that a contaminant might pose a
significant current or future risk or contribute to a cumulative risk which
is significant. The criteria for including chemicals in the ROD risk
discussion was a carcinogen risk level within or above the acceptable risk
range, i.e., 1 x 10~* to 1 x 10~*, or a hazard quotient (HQ) greater than
0.1. The groundwater pathway is the only exposure media whose risk levels
are at a significant level. For this reason this discussion will focus on
the groundwater pathway.
The exposure point concentrations represent the upper 95% confidence limits
of the arithmetic means. If the upper 95% confidence limit exceeded the
maximum, the maximum concentration was used for the exposure point
concentration. The exposure concentration information for the groundwater
pathway is presented in Tables 6-1, 6-2, and 6-3.
6.1.2 Exposure Assessment
» potential for current exposure to contaminated media at the Site is
..~ghly unlikely. Since water at the Site is supplied by the local water
company there is no current exposure .to groundwater. In addition, it is
highly unlikely that a worker would receive any exposure to subsurface
soil, or prolonged exposure to contaminated sediment and surface water.
Given the presence of residential areas in the vicinity of the Site and the
use of groundwater by some area residents, a future residential scenario
was evaluated.
The pathways associated with groundwater at this Site included ingestion of
contaminated groundwater, inhalation of volatiles while showering and
cooking, dermal (skin) absorption while showering. Other potential
exposure pathways evaluated were the incidental ingestion and dermal
contact with surface water and sediment. Exposure pathways involving air
as a medium were not considered due to the lack of evidence for surficial
contamination and extensive grass and vegetative cover at the Site.
Populations that could potentially be exposed to Site contaminants are
child and adult residents living on the Site, and children and adults
living near the Site who might visit or play on the Site. Based on these
potential receptors, seven general future exposure pathways were selected
for further numerical risk quantifications
• Ingestion of groundwater
:*:|: ^
';.:;• • Inhalation of volatiles while showering and cooking
-------
17
TABLE 6-1
SUMMARY OF CONTAMINANTS OP CONCERN
PARA-CHEM SUPBRFUND SITE
CONTAMINANT
Aluminum
Antimony
Arsenic
Barium
Cadmium
Calcium
CftroTBii_Tm
Cobalt
Copper
con
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Sodium
Thallium
Vanadium
Zinc
GROUND
WATER
(MG/L)
2.27
. .
0.003
- .
. _
- -
- _
- -
- -
- -
_ _
14.1
. .
- -
.- -
- -
-- _
_ -
- -
SURFACE
WATER
(MG/L)
- -
. .
_ -
- -
. -
- .
. .
- -
- -
. .
. .
- -
0.0237
- -
. .
. .
-'-
. .
. .
0.0243
STREAM
SEDIMENT
(MG/KG)
. -
. .
- -
- _
- -
- .
- -
. -
. .
. -
. .
- _
- .
•» •»
•• •»
. -
.-.
- .
- .
26.7
SUBSURFACE
SOILS
(MG/KG)
46400
- -
1.6
159
- -
. .
•» «•
. -
- -
- -
- -
- _
272
- _
• -
- -
. .
. -
. -
170
SLUDGE
(MG/KG)
32000
3120
2.8
. -
0.54
- _
38.6
_ -
- -
- -
- -
- _
129
- —
- -
. _
- -
- _
- -
4550
-------
18
TABLE 6-1 (cont.)
SUMMARY OF CONTAMINANTS OF CONCERN
PARA-CHEM SUPBRFUND SITE
CONTAMINANT
Acetone
Benzene
Bis ( 2-ethylhexyl )
phthalate
BraBodichloroflte thane
2-Butanone
Butylbenzylphthalate
Chloroethane
Chloroform
Dibutylphthalate
, 1-Dichloroethane
l , 2-Dichloroethane
1 , 1-Dichloroethene
1 , 2-Dichloroethene
Dimethylphthalate
Dioctylphthalate
Ethyl acrylate
Ethylbenzene
Isophorone
Methylene Chloride
2-Methylphenol
4-Methylphenol
Naphthalene
Pentachlorophenol
Phenol
GRblAUj
WATER
(M6/L)
4.9
0.005
0.03
- -
79
0.002
- -
0.022
- -
0.95
0.005
4.3
0.2
- - •
- - '
- - .
. ~*-
. -
0.021
- -
- -
- .
- -
SURFACE
HATER
(M6/L)
_ .
- .
- -. •
0.0002
. .
_ _
. -
0.0006
*• tm
0.0006
- .
0.002
- -
- - •
- -
<•» «*
. -
. -
- -
4V «•
. -
. .
- .
- -
STREAM
SEDIMENT
(MG/KG)
. -
- .
. .
_ -
_ -
- .
. -
- -
- -
_ -.
«» «»
- -
- -
- -
. - •
- -
- -
- -
- -
. _
. .
- -
SUBSURFACE
SOILS
(MG/KG)
0.101
. -
- .
0.007
231
- -
- -
_ -
0.123
- -
0.011
- .
_ -
- -
1.3
• «•
_ .
0.01
- - •
- .
_ _
0.002
- -
SLUDGE
(MG/KG)
. .
- -
_ .
1.1
5200
. -
- .
- .
19
16
350
3.6
. -
«» •»
- -
. .
_ -
0.088
. -
0.64
. _
24
- -
-------
19
TABLE 6-1 (cont.)
SUMMARY 07 CONTAMINANTS OP CONCERN
PARA-CHBM SUPBRPUND SITE
CONTAMINANT
GROUND
HATER
(MG/L)
ORGANICS (cont.)
Tetrachloroe thane
Tetrahydrofuran
Toluene
1,2, 4-Trichlorobenzene
1,1, 1-Trichloroethane
1,1, 2-Trichloroethane
Triohloroethene
Xylene (Total)
PESTICIDES
,4 '-DDE
14, 4 'DDT
0.058
62
6.1
- -
12
0.017
1.1
0.065
. -
- .
SURFACE
WATER
(MG/L)
STREAM
SEDIMENT
(MB/KG)
SUBSURFACE
SOILS
(M6/K6)
SLUDGE
(MG/KG)
- _
0.04
- .
- -
0.002
- -
_ _
_ -
- -
- -
- .
. -
0.001
- -
. -.
- -
• «•
• *»
. -
. .
0.11
0.015
0.003
- -
0.577
0.002
0.001
0.022
- .
120
. -
590
- -
14000
3.1
3.4
5
0.059
0.07
-------
20
TABLE 6-2
GROUNDWATBR INGBSTIOH EXPOSURE ASSUMPTIONS
PARA-CHEM SOUTHERN, INC. SUPBRPUND SITE
Ground
IVncTK
cw -
IR
EF »
ED -
BW «
AT -
Assumptions:
CW -
IR -
EF
ED -
BW a
m
AT -
••^
water Ingestion Dose CW x [R x EF » ED
(mg/kg-day) * BWxAT
Chemical concentration in gnundwater (tng/L)
digestion me (L/day)
Exposure frequency (days/year)
Exposure duratioo (yean)
Body weight (kg)
?•
Avenging tune (days)
Upper 95% confidence limit of the mean concentranon in groundwater.
1 liter/day, for the taore child (1-6) resident.
1 liter/day, for the future child (7-12) resident.
2 liten/day, for die name adult resident (EPA, I991a).
350 days/year for die future children and adult residents (EPA. 1991a).
6 yean for die future child (1-6) resident (EPA, 1991a).
6 yean for die future child (7-12) resident (EPA, I991a).
18 yean for die future adult resident (EPA, 199U).
IS kg for the future child (1-6) resident (EPA. 199 U).
27 kg for die feture child (7-12) resident (EPA, 1985).
70 kg for die future adult resident (EPA, 199U).
Exposure duration (yean) x 365 days/year for evaluating ooncancer risk.
-------
21
TABLE 6-3
CHRONIC REFERENCE DOSES
PAR&-CHBM SOUTHERH, INC. STJPBRPUND SITE
1992
ATSOR 1M»
006-02
gPA.itia
£866-01 '
ZOOE-01
1.006-02
iRiantta
4.006-03
gQOE'fOO
IRISL1892
3.006-
41 4.006—03 AT8DKI
.25.
* T?» oral MO lor tw ehHMcM «•* ia*d •> V* MMion ROX
•MM^ ^^afl^^d ^Mi^» ^^«^^^i«A^Ht ta •^A^M» A
Bonmovi novMOMBraMB VIVKKVI^
thitt
fWQDy«Mur*«tt»W»littodtom»ol^Dttty«nd«bodri*OTorTO^
Ctwntori It ntt ol
-------
22
• Dermal absorption while showering
• Incidental' ingestion of surface water*
• Dermal contact with surface water*
• Incidental ingestion of sediment"
• Dermal contact with sediment*
* Child (age 7-12 years) resident only
In order to quantify the exposure associated with each pathway, various
standard assumptions were made for key variables in the exposure
calculations. These variables include the contaminant level in the medium,
usually referred to as the exposure point concentration; and the amount of
the contaminant taken into the body, or chronic daily intake, which must be
calculated using a number of assumptions. The result of the exposure
assessment is a set of tables showing a calculated average daily intake
value for each contaminant or compound, as well as a summary value for each
exposure pathway.
The exposure assumptions for the groundwater ingestion pathway are
~">ntained in Table 6.2. Additionally, for the evaluation of exposure to
latiles from showering, cooking, dish washing and laundering, the
-sumption was made that this exposure is equivalent to the ingestion rate
of two liters/day. The assumptions for the surface water and sediment
pathways were for a six (6) year exposure by a twenty seven (27) kg child.
The exposure frequency was assumed to be fortyfive (45) days/year and 2.6
hours/day. The water and soil ingestion rates were fifty (50) ml/hour, and
one hundred (100) mg/day, respectively.
6,1,3 Toxi.ci.tv Assessment of Contaminants
In this portion of the Baseline Risk Assessment, the toxic effects of
contaminants were investigated and evaluated by EPA. The critical
variables needed to calculate estimates of risk to human health and the
environment were obtained from the EPA toxicological database. Critical
toxicity values for the Site contaminants are presented in Tables 6-3 and
-------
23
TABLE 6-4
CANCER SLOPE FACTORS
PARA-CHBM SOUTHERN, INC. SUPERFUND SITE
OML
FACTO*
IRS. 1»i»
BS. itn i
_SL
««*-•"
ra»-gi
_iZS£:
-------
24
ope factors (SPs) have been developed by BPA's Carcinogenic Assessment
Group for estimating excess lifetime cancer risks associated with exposure
to potentially carcinogenic contaminants of concern. SPs, which are
expressed in units of (mg/kg-day)*1, are multiplied by the estimated intake
of a potential carcinogen, in mg/kg-day, to provide the upper bound
estimate of the excess lifetime cancer risk associated with exposure at
that intake level. The term "upper bound" reflects the conservative
estimate of the risks calculated from the SF. Use of this approach makes
underestimation of the actual cancer risk highly unlikely. Slope factors
are derived from the results of human epidemiological studies or chronic
animal bioassays to which animal-to-human extrapolation and uncertainty
factors have been applied (e.g., to account for the use of animal data to
predict effects on humans).
Reference doses (RfOs) have been developed by EPA for indicating the
potential for adverse health effects from exposure to contaminants of
concern 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. Estimated intakes of contaminants
of concern from environmental media (e.g., the amount of a contaminant of
concern ingested from contaminated drinking water) can be compared to the
RfO. RfDs are derived from human epidemiological studies or *n*"|y1 studies
to which uncertainty factors have been applied (e.g., to account for the
use of animal data to predict effects on humans).
?cinogenic contaminants are classified according to EPA's weight-of-
.idence system. This classification scheme is summarised belowt
•
Group At Known human carcinogen.
Group Bis Probable human carcinogen, based on limited human
epidemiological evidence.
Group B2s Probable human carcinogen, based on inadequate human
epidemiological evidence but sufficient evidence of
carcinogenicity in animals.
Group Cs Possible human carcinogen, limited evidence of
carcinogenicity in animals.
Group D» Hot classifiable due to insufficient data.
Group Bs Hot a human carcinogen, based on adequate *"^i»fll studies
and/or human epidemiological evidence.
6.1.4 Risk
The final step of the Baseline Risk Assessment, generation of numerical
estimates of risk, was accomplished by integrating the exposure and
xicity information. Tables 6-4 and 6-5 present summaries of the total
-------
TABLE 6-5
HAZARD INDICES
PARA.-CHBK SOUTHERN, INC. SUPBRFUND SITE
25
SURFACE WATER I SURFACE WATER
INGESTION ABSORPTION
NO NO
NO NO
NO I NO
SEDIMENT
RJPTION
NO
NO
NO
NO
NO
GROUNOWATER
INGEST1ON
J.7E+00
NTV
TOTAL
5.2E+00
NTV
5.3E-02
7.9E-06
7.6E+OI
CHEMICALS
ORGANICS
Bromedemeratmam
01
6.7E-01
NTV
S.lEt-01
1.1E-MM
ME-02
6.2E-01
NTV
1.8E»00
7.6E-KX)
4.5E-01
2.0E+01
3.5E-03
t.ee-01
6.7E-01
NTV
3.4E+01
7.1 E-Qj
1.7E-03
t.l-Dichloco*imn«
l.2-Dlchkxo«m«n«
I.I -Dichtoto«tn«n»
1.2-0ichhxo>m«n«
eMoridi
NTV
3.6E-01
5.0E+OQ
9.9E-01
1.7E+02
INORGANICS
Aluminum
ATMfiC
Man
Tom
. NTV-NotOBOtyvJ
NA«Notapplcabt«
-------
26
TABLE 6-6
LIFETIME CANCER RISK
PARA-CHKM SOUTHERN, IMC. SUPBRFUND SITE
CHEMICALS
ORQANICS
Banzena
6*3(2 •• wttyltwxyi )pwtm^*
p/on u^duuf u0u uu M
GMofolQfin
12* )icNoroetnan*
1|1w jtcttofooiftont)
MMnyfon0 criofKitf
Tttracttoreemene
1 .1 ,2-Tricttofoetnand
Tncntorootncns
INORGANICS
Araanc •
Total
GflOUNOWATEH
INQESTION
2E-06
7E-06
NO
INHALATION
OFVOCs
SURFACE WATER i SURFACE WATER
INGESnON i ABSORPTION
3E-06I NO
MA j NO
NO
NO
TOTAL
6E-06
7E-06
NO < tE-091 46-101 2E-09
2E-06I 46-051 2E-10I 7E-11I 4E-05
7E-06I IE-OS I Nti>
NO
46-021 2E-02I 6E-08I 4E-08
2E-06I 8E-07I N6
5E-OSI 3E-06I NO
2E-OSI 2E-O5I NO
2E-04I 2E-04I NO
8E-05
NA
4E-02I 2E-02
NO
NO
NO
NO
2
6
3
&
4
NO ! 3
NO
E^OSI
:-O2
E-06
B-051
•-05 1
1--04
BE -05
6E-06I 4E-08I 6E-02
NA.NotappiKMtia
NO • NotdauciBd
a:\HOUC\1NP\aMOOvai4\MMNM01AI
-------
27
.card quotient (non-carcinogenic risk) and total cancer risk associated
with the Site. Since the hazard indices associated with the young child
are higher than for the older child or adult, only the values for the young
child were summarised in this decision document.
For carcinogens, risks are estimated as the incremental probability of an
individual developing cancer over a life-time as a result of exposure to
the carcinogen. Excess life-time cancer risk is calculated from the
following equation*
Risk - GDI x SP
Wheret
Risk - a unit less probability (e.g., 2 x 10'*) of an individual
developing cancer;
GDI - chronic daily intake averaged over 70 years (mg/kg-day; and
SF * slope-factor, expressed as (mg/kg-day)'1
-hese risks are probabilities that are generally expressed in scientific
notation (e.g., 1 x 10*4 or IB-4). An excess lifetime cancer risk of 1 x
••»-• indicated that, as a reasonable maximum estimate, an individual has a
In 1,000,000 chance of developing cancer as a result of Site related
.^posture over a 70 year lifetime under the specific exposure conditions at
the Site. EPA generally uses the 1B-4 to 1E-6 risk range as an "acceptable
risk range" within which the Agency strives to manage risks as part of the
Snperfund cleanup. Once a decision has been made to take an action, the
Agency has expressed a preference for cleanups achieving the more
protective end of the range (i.e., 1B-6).
The potential for noncarcinogenic effects is evaluated by comparing an
exposure level over a specified time period (e.g., life time) with a
reference dose derived for a similar exposure period. The rate of exposure
to toxicity is called a hazard quotient (HQ). By adding the HQs for all
contaminants of concern that affect the same target organ (e.g., liver)
within a medium or across all media to which a given population may
reasonably be exposed, the Hazard Index (HI) can be generated. The RQ is
calculated as follows*
Non-Cancer HQ • COI/RfO
Where*
GDI - Chronic Daily Intake
RfO • Re rence Dose; ar
GDI and Rfd ire ex assed in the £ a units and represent the same exposure
riod (i.e., aferor._c, subchronic, ->r short-term).
-------
28
.fetime carcinogenic risk for a hypothetical future on-Site resident over
a thirty (30) year period is estimated to be 6.0 x 10**. The risk is
primarily due to potential ingestion of groundwater and inhalation of VOCs
while showering. Risk values of this magnitude exceeded acceptable cleanup
goals as described in the National Oil and Hazardous Substances Contingency
Plan (NCP), 40 C.F.R. Part 300.430(e)(2). Groundwater ingestion and
inhalation of VOCs pathways accounted for the greatest risk associated with
this Site. Approximately 99% of the total carcinogenic risk is.
attributable to exposure to 1,1-Dichloroethene.
Future non-carcinogenic risk is estimated as HI • 310 for future on-Site
children and HI - 100 for future on-Site adult residents. In both cases,
exposure through ingestion of groundwater and inhalation of VOCs while
showering are major contributors to the risk. Exposure to 2-Butanone, 1,1-
Dichloroethene, 1,1,1-Trichloroethane, and Trichloroethene accounted for
the largest percentage of this risk. The risk associated with exposure to
surface water and sediment are below the Agency's level of concern.
It should be noted that there is some degree of uncertainty associated with
the calculated numerical estimates of human health risks generated in the
Baseline Risk Assessment. This is due to the considerable number of
assumptions required to provide variables in the equations, and the
specific selections of each variable from a range of possibilities.
*- the absence of empirical or Site specific data, assumptions are
reloped based on best estimates of exposure or dose-related
_ ^lationships. The risk estimates for this Site are based on a number of
assumptions that incorporate varyingrdegrees of uncertainty resulting from
many sources including!
• . Environmental monitoring and data evaluation;
• Assumptions in the selection of exposure pathways and scenarios;
• Choice of models for exposure, and input parameters to these
models;
• Choice of models for evaluation of toxicological data in dose-
response quantifications, and;
• Assumptions in the expression of noncarcinogenic and carcinogenic
risks.
fi.2 Environmental Risks
Because land use on the surrounding properties is coned for both
residential and industry usage, the ecological communities surrounding the
Para-Cham Southern Site have been altered from their natural state. No
state or federally designated endangered or threatened species are found at
or near the Site. For these reasons, the Baseline Risk Assessment
• :ermined thai? the potential for environmental risks was low.
-------
29
..•a following contaminants were selected for evaluation based on their
presence in surface water (Inorganicst aluminas, manganese/ sodium, cine;
Organicss 1,1-Dichloroethene, 1,1,1-Trichloroethane, Tetrahydrofuran).
Only aluminum and zinc were present at concentrations that posed a
potential risk to aquatic life. Aluminum levels may pose a risk to aquatic
life, however, the on-Site levels do not differ from the background levels.
This would indicate that the aluminum concentrations can not be attributed
to sources originating at the Site and are reflective of background
concentrations present in the surface water.- '*- " ~r"* ••••*•" -• • •
^^.:f -f •.>*...». . . .. .-..-.-£• ' ~~ .::" ' .' •'-
Contaminants present in the sediments that were selected for evaluation
consisted of inorganics only (aluminum, manganese, cine). For these
contaminants, only cine could be evaluated based on available criteria.
Zinc levels were below the biological effect levels established by the
National Oceanic and Atmospheric Administration, therefore no risk to
benthic life is expected on this basis.
Two (2) macroinvertebrate evaluations were performed on this unnamed
tributary in June 1985 (Aquatic Analysts) and May 1991 (Shealy ESI). The
1985 report concluded that the Site had impacted the microinvertebrate
community within the unnamed tributary. The 1991 report indicated that
conditions had improved and the unnamed tributary exhibited good water
quality.
~^e RI Sampling results indicate that groundwater is discharging from the
lifer into the on-Site unnamed tributary at low levels. These levels are
—»t considered ecologically significant at this time. Should these levels
increase, which could occur by way of continued movement of the groundwater
contaminant plume, contamination could pose an ecological threat to the
unnamed tributary.
7.0 REMEDIAL ALTERNATIVES
The Feasibility Study (FS) considered a wide variety of general response
actions and technologies for remediating soil and groundwater at the Site.
Table 7-1 summarizes these response actions and technologies, and provides
the rationale for why each was retained or rejected for further
consideration in the development of remedial alternatives.
Based on the FS, Baseline Risk Assessment, and Applicable or Relevant and
Appropriate Requirements (ARARs), the remedial action objectives (RAOs)
listed below were established for the Site. Alternatives were developed
with the goal of attaining these Remedial Action Objectives!
• Prevent ingestion of groundwater containing any carcinogen
concentrations above Federal or State limits, or if there is no
established limit, above levels which would allow a remaining
excess cancer risk of greater than 10** to 10~V
•'• '. 4"
-------
30
• Prevent ingestion of groundwater containing any non-carcinogen
concentrations above Federal or State limit*, or if there is no
established limit, above levels which would allow an unacceptable
remaining non-carcinogenic threat (HI greater than 1.0).
• Restore the groundwater system to potential productive use, by
cleanup to the standards described above, and by preventing the
migration of the pollutants beyond the existing limits o'f the
contaminant plume.
• Prevent ingestion or direct contact with contaminated sludge
having greater than a 10"* to 10~* excess cancer risk, or
exceeding the allowable health threat (HI greater than 1.0) for
non-carcinogens.
• Prevent migration of contaminants from the sludge to groundwater,
which would result in groundwater contamination in excess of
Federal/State limits or health-based maximum levels.
• Monitor contaminant concentrations in the unnamed tributary, and
maintain water quality in accordance with Federal and South
Carolina Ambient Water Quality Criteria for surface waters.
• Characterization of the five anomalies discovered during the soil
gas survey through additional sampling.
7.1 Description of Remedial Alternatives
The technologies identified in Table 7-1 considered potentially applicable
for remediating the Site were further evaluated on the effectiveness and
implementability criteria. Table 7-2 lists those which passed this final
screening, and outlines the technology components of each of the five (5)
remedial alternatives proposed for remediation.
-------
TABLE 7-1
SCREENING OF REMEDIAL TECHNOLOGIES
PARA-CHEM SOUTHERN, IMC. FEASIBILITY STUDY
am°*ri£tl££0a~ Mctooioir Process Options Bffeotlveness
No Action environmental Sampling May not achieve
Monitoring remedial action
objectives.
Institutional Access renoing Reliability is
Actions Restrictions dependent on
long-term
maintenance.
Thla option does
not alter the
waste
characteristics.
Deed ., Dependent upon
restrictions continued
implementation in
the future. Does
not affect
characteristics
of waste. Not
reliable.
Implementabllity
May not be
acceptable to
local community or
regulatory
agencies.
Readily
implementable from
technical and
administrative
perspectives.
•I .
Requires legal
aeslstance for
development of
specific
components and
legal authority
for insurance, of
effective • ••
Relative Cost
tow
tow capital,
low
maintenance
tow capital,
no
maintenance
Containment
Cover
Soil Cap
More permeable
than other non-
synthetic liner
materials.
implementation.
Technical anid
administrative
implementabllity
has been
demonstrated at
numerous sites.
Can be constructed
using proven ;
methods and , .
standard •> i
earthmovlng •
equipment. : ;
tow capital,
low
maintenance
-------
TABLE 7-1 (COHT.)
SCRBKHIH6 OF RRMBDIAL TECHNOLOGIES
PARA-CHBM SOUTHERN FEASIBILITY STODT
otl
Procee. option.
Bfffeoti
Implementability Relative Coet
Clay cap
Relatively leae
permeable than
other non-
aynthetio liner
materlale. Can
be conatructed
with MT'cm/eec
permeability..
Technical and
adminivtrative
baa been
demonstrated at
numeroua Sitea.
Can be conatructed
uaing proven
methode and
•tandard
earthmovlng
equipment.
Moderate
capital, low
maintenance
Synthetic
membrane
KID nail 8LODOI
Containeent
(cont)
Cover
Multimedia cap
Oreat abort-term
effectiveness has
been demonstrated
when uaed in
multimedia cape
with other
capping media.
Stability,
durability, and
strength decrease
without uae of
other cover
media.
Relatively leaa
auaceptible to
cracking and
weathering than
other materiala
that are uaed
aingly for waete
cap conatruction.
Technical and
administrative
implementability
baa been
demonstrated at
numeroua
landfilla. Can be
constructed uaing
proven methode and
equipment uaed in
conatruction of
sanitary
landfilla.
Caq be built uaing
•tandard equipment
and Mthode proven
at other eurrace
ia^oundeenta•
Moderate
capital, low
maintenance
Moderate
capital, low
maintenance
-------
TABLE 7-1 (CONT.)
SCREENING OF REMEDIAL TECHNOLOGIES
PARA-CHEM SOUTHERN FBASIBILITT STUDY
Oeneral
^Actions
technology
Process Option*
effect!'
Xmplsmentablllty Relative OMt
Removal Actions
Bulk Sludge
- ral
excavation
Treatment Action* Thermal
Physical/
Chemical
Thsrmal
destruction
Thermal
separation
Dewatering
Soil Mashing
Chemical
extraction
effective using
alternative
techniques.
Dragline and/or
clam shell
excavation may be
appropriate.
effective for
removal of
oroanlce and
volatile metals.
Potentially
applicable for
organics removal.
Effectiveness
strongly
dependent on soil
matrix.
effective for
separating Mater
from solid.
Potentially
effective for all
types of
contaminants.
Potentially
effective for all
classes. Site
speciflo
treatabillty
testing Mae
favorable.
The relatively Moderate
small amount of
sludge in the
concrete settling
basin makes large
scale excavation
less impleoentable
than those
designed for Site-
specific
application.
Implenentable. Very high
economically not
feasible for
material Mlth high
Mater content.
Selected for use Very high
at several NPL
Sites.
Oily sediments can Moderate
be difficult to
dswatsr.
Formulation of High
suitable Mashing
fluid is difficult
for complex
mixtures.
Potentially High
implementaole.
-------
TABUS 7-J. (CONT.)
SCRBBMING OF REMEDIAL TECHNOLOGIES
PARA-CHEM SODTHBRH FEASIBILITY STUDY
„ Actions Tsi'iliiti il < my
Chemical
dechlorination
Bffeotlveness
Potentially
effective for
chlorinated
organics.
Implement ability
Potentially
implemsntable .
Demonstrated at
several Sites.
Relative Cost
High
Stabilication/
Solidification
MKDIPMl BMDOB
(conty
Treatment Actions
(cent)
Biological
Systems
Batch
biodegradation
Disposal
In situ
biodegradation
On-Site Disposal Landfilling
Potentially
effective cor all
types of
contaminants.
Effectively
lamobilices semi-
volatiles and
non-volatiles.
Potentially
effective for
organica removal
only. Bench
testing would be
required to
determine
possible extent.
Potentially
effective for
organics removal
only. Bench
testing would be
required to
determine
possible extent.
Effectiveness is
dependent on
proper long-term
maintenance of
containment
facility.
Implementable.
Demonstrated on
wastes containing
complex organic
mixtu
Moderate
cures.
Potentially
implementable if
sludge is not
toxic to
microorganisms.
Potentially
inplementable if
sludge is not
toxic to
microorganisms.
Technically
feasible by use of
standard
landfilllng
methods. May not
be favorable from
an administrative
point of view.
High
High
High
-------
TABUS 7-1 (CONT.)
SCREBHIHG OF REMEDIAL TECHNOLOGIES
PARA-CHBM SOUTHERN FBA8IBILITT STUDY
General Response
^Actions
Technology
Bffectl
TrnplnaBntsMlltj Relative Ooet
Off-Site
Disposal
Backfilling
Landfilling
Effective if
prior treatment
meets regulatory
reetriotlons
tffectire
oontalnaent is
dependent on
proper long-term
maintenance of
facility by a
third party.
Potentially
. implementable, .
depending on
success of
treatment prior to
backfilling
Technical
feasibility is
dependent on
availability of
capacity at time •
of remediation.
May not be
favorable from an
administrative
point of view.
Low
High
-------
TABLE 7-1 (COHT.)
SCRBBHING OF REMEDIAL TECHNOLOGIES
PARA-CHBM SOOTHBRH FBASIBILITT STUDY
General Response)
Actions
tnniOMt dtOOHD-
MaXBIl
Ho Action
Institutional
Actions
nemaJial
Tec ihnol ooj
Bnvironmental
Monitoring
Access
restrictions
Alternate water
supply
Process Options
Sampling
Deed restrictions
.,
Municipal water
supply
Bffectivenees
Oseful means of
documenting
characteristics
of ground-
water, but does
not alter
characteristics
of waste.
Dependent upon
continued
implementation
in the future.
Does not affect
characteristics
of waste.
Effective means
of preventing
exposure to
Implementability
Technically
implementable,
but alone may not
meet with
approval of local
community or
regulatory
agencies.
Requires legal
assistance for
development of
specific
components and
legal authority
to ensure
implementation.
Water users can
be added to
system using
Cost
Low capital.
moderate
'
Low
Moderate
capital.
OCM
OCM
low
Monitoring
Oroundwater
monitoring
Collection
Removal
Extraction wells
affected ground
water, but does
not reduce the
toxlcity,
mobility, or
volume of the
waste.
Oseful means of
documenting
character1stics
of ground-
water, but does
not alter
characteristics
of waste.
Proven
effective in
Site-specific
application.
Requires approval
by local utility
authority and'
definition of
service area.
Technically
implementable,
but alone may not
meet with
approval of local
community or
regulatory
agencies.
Currently
operating system
in place.
Low capital,
moderate OCM
high capital,
Io5 OftM
-------
TABLE 7-1
SCREENING OP REMEDIAL TECHNOLOGIES
PARA-CHBlf SOUTHERN FEASIBILITY STUDY
General Response
Actions
Treatment?
Remedial Process option* Bf feotiveness
Technology
Biological Aerobic Less
chlorinated
compounds can
be degraded.
Anaerobic Reductive
decblorination
can yield
aarobically
degradable
compounds.
Phyeical/Chemio Stripping ' Effective for
al treatment treatment of
VOCa.
'*
Adsorption Currently
effective on
organioe at
Site.
Implementability
Require* either
infiltration/inle
otlon of water to
the aquifer or
batch treatment
reactor •.
Requires
infiltration or
injection of
water to the
aquifer.
Can be
implemented in
conjunction with
other
technologies
Can be
implemented in
conjunction with
other
technologies
Cost
High capital,
low operating
Moderate
capital, low
operating
Low capital,
moderate
operating
High capital
cost, high
operating
cost
-------
TABLE 7-1 (CONT.)
SCRKKMING OF REMEDIAL TECHNOLOGIES
PARA-CHEM SOOTBBRM FEASIBILITY STODT
Action*
•ffeotlv
Impleaintability Oomt
(oont.)
Treatment (cont.)
Off-Bit*
treatment
Diacharg*
Xn-aitu
treatment
On-Blte
diepoaal
POTW
RCRA facility
Bioraclamation
Local atcaaa
Potentially
applicable
where organici
are preaent.
Bffective if
facility ia
available.
Potentially
effective with
VOCa
Bffective and
reliable
dlacharge
method that,
except for
volatilisation
doea not alter
waate
oharaoteriatica
Can be
implemented with
approval from
Sewer Authority.
No RCRA water
treatment
facility nearby..
Muat be
tranaported.
Limited
commercial
availability for
in-altu treatment
of chlorinated
VOCa on a pilot
acale.
Reguirea MPOBS
diaoharge permit.
Capital coat
low, low
operating
coat
Tranaportatio
n coat
extremely
high
High capital
coat,
moderate
operating
coat
Low capital,
very low OCM
Infiltration
Mot affective
in clayey
aolla. Low
hydraulic
oonduotlvitiea
will limit rate
of
infiltration.
Can be built
uaing atandard
conatruction
methoda.
Modarat*
-------
TABLE 7-1 (CONT.)
SCRBBMIHG OF REMEDIAL TECHNOLOGIES
PARA-CHBM SOUTHERN FEASIBILITY STODT
General
Action*
Technology
Process Option* Iffectiveaess Imp} ss»int-iM.li.ty Ooet
Off-Bit*
disposal
Spray irrigation
Pipeline to river
or stream
Publicly owned
treatment work*
May require
storage during
winter when low
evapotranapirat
ion would
reduce
effectiyeneee.
Mould be
effective in
traneporting
water
•ffeotive and
reliable
discharge
nethod that,
uaed alone doea
not alter waete
characteristic*
Can be High capital,
loplemented using high OftM
currently
available
equipment.
Requires NPDB8 High capital,
discharge permit, low O&M
rights-of-way,
and under-highway
crossings.
Requires approval Moderate
fro* sewer capital, low
district. OfcM
-------
40
SABLE 7-2
Alternative
1
2
3
4
5
i
FINAL REMEDIAL ALTERNATIVES
PARA-CHEM SOUxuJstui IHC. SUP4RFUND SITE
Description of Alternatives
No Action
Institutional Controls for all media t Deed and Access
Restrictions .
Pump and Treat Affected Groundwater s Maintain control of
groundwater flow with existing or modified extraction wells
and reduce toxicity with treatment.
Capping of Sludge Areas with Groundwater Extraction and
Treatment i Construct multimedia cap over sludge combined
with groundwater treatment outlined in Alternative 3.
Removal and Disposal of Sludge and Groundwater Extraction
and Treatment t Groundwater treatment as outlined in
Alternative 3 combined with removal of sludge and treatment
by one of the following;
5a. Thermal Destruction and Off -Site Disposal
5b. Landfill in Off -Site Facility
Unit
-------
41
»U alternatives except 1 (Mo Action) and 2 (Institutional Controls)
:lude sampling to insure that all contaminated groundwater at
ocentrations that exceeded the remediation goals trill not migrate beyond
Site boundaries. Additionally, all of the alternatives include six (6)
Five (5) Tear Reviews to be conducted during the assumed thirty (30) year
Operations & Maintenance period. The cost of these reviews, $41,700, is
included with the capital costs but was calculated using the same five
percent discount factor as O&M costs.
Certain ARARs are applicable to each alternative. Alternatives 2*
(Institutional Controls), 3 (Groundwater Treatment) and 4 (Capping of
Sludge and Groundwater Treatment) would not satisfy the requirements of
the South Carolina Hazardous Haste Management Regulations (SCHWMR), Reg.
61-79.264, which require removal of contamination "to the maximum extent
possible.* Alternative 5 (Treatment of Sludge with Groundwater Treatment
would, assuming successful implementation, comply with this ARAR.
Alternatives 3 (Groundwater Treatment), 4 (Capping of Sludge and
Groundwater Treatment) and 5 (Sludge Treatment and Groundwater Treatment)
involve materials handling and potential generation of particulates, and/cr
VOC emissions from treatment, and thus, must comply with the South Carolina
Ambient Air Quality Standards (AAQS) which implement the South Carolina
Pollution Control Act, and the National Emission Standards for Hazardous
Air Pollutants (HBSHAP) under the Clean Air Act. Alternative 5b (Sludge
Treatment through Landfilling) includes landfill disposal of a potential
hazardous waste and, therefore, could be required to comply with RCRA land
disposal restrictions (LDRs), (40 C.F.R. Part 268, SCHWMR 61-79.268) if the
-Tudge and/or soils are shown to be hazardous wastes subject to land
iposal requirements (40 C.F.R. Part 261, SCHWMR 61-79.261). Finally,
3. Department of Transportation (DOT), EPA (40 C.F.R. Part 262), and
SCDHBC (SCHWMR 61-79.262) regulations governing the transportation of
hazardous materials would also apply to Alternative 5 if the sludge and/or
soils prove to be hazardous waste.
The treatment system related to Alternative 5a (Thermal Destruction of
Sludge) and 5c (Biological Treatment of Sludge) may produce a residual
sludge that may be subject to the identification (40 C.F.R. Part 261,
SCHWMR 61-79.261), transportation (40 C.F.R. Part 262, SCHWMR 61-79.262),
manifestation (40 C.F.R. Part 263, SCHWMR 61-79.263), and land disposal
restriction (40 C.F.R. Part 268, SCHWMR 61-79.268) requirements of RCRA, if
the resulting residual sludge is determined to be a RCRA hazardous waste.
Additionally there are ARARs which are applicable, or relevant and
appropriate, to each of the alternatives addressing groundwater. Site
groundwater is classified by South Carolina as Class GB (SC Water
Classifications and Standards, Regulation 61-68), and by EPA as Class IIB
(Guidelines for Ground Water Use and Classification, EPA Ground Water
Protection Strategy, US EPA 1986). Alternative 2 (Institutional Controls)
would not meet the relevant and appropriate ARARs concerning groundwater as
a potable water source, the' National Primary and Secondary Drinking Water
Standards, promulgated in 40 C.F.R. Parts 141-143, and the State of South
Carolina Primary Drinking Water Regulations, SC Reg. 61-58, because Site
oroundwater violates numerous MCLs specified in these regulations. Also,
j;;;j:j> CBRCLA preference for treatment to reduce toxicity, mobility, or volume
^contaminants wherever possible would not be satisfied by this
alternative. The remaining alternatives 3 (Groundwater Treatment), 4
(Capping of Sludge with Groundwater Treatment) and 5 (Disposal of Sludge
with Groundwater Treatment) would achieve these standards. Alternatives 3
-------
42
(Groundwater Treatment), 4 (Capping of Sludge and Gronndwater Treatment)
»nd 5 (Disposal of Sludge and Groundwater Treatment) would be subject to
» following major applicable ARARss South Carolina Ambient Air Quality
andards (SC Regulation 62.5), national Emissions Standards for Hazardous
Air Pollutants (NKSHAPs, 40 C.P.R. Part 61), Clean Water Act Discharge
Limitations (40 C.F.R. S 403.5), and the Clean Water Act Pretreatment
Standards (40 C.F.R. Parts 122, 125, 129, 133, and 136).
The "OiM cost" included for each alternative refers to the costs of
operating and maintaining the treatment described in the alternative, for
an assumed period of thirty 30 years. All of the Alternatives except
Alternative 1 (Mo Action) have anticipated O&M costs. Such costs would
include, primarily, periodic inspections of the Site. The O&H costs were
calculated using a five percent discount rate per year.
7.2.1 Alternative 1t No Action
The No Action alternative is retained as the baseline case for comparison
with other alternatives. No remedial actions would be performed on the
media of concern at the Site. For the purpose of evaluating the 'No
Action" alternative, it will be assumed that the existing groundwater
extraction and treatment system is not operating. The entire Site, as
defined during the RI, would remain in its present condition. The only
active component of this alternative is long-term groundwater monitoring.
This program would be implemented to assess the effect of waste
contaminants on the Site over a thirty (30) year design life. Gronndwater
-*-. the Site would be sampled and analyzed semi-annually for Site-specific
ttaminants of concern. The monitoring program would be reevaluated every
.
-------
43
fencing and deed restrictions at the Sit*. Security fencing installed as
~trt of this alternative would consist of a six (6) foot high chain-link
ice with at least one strand of barbed wire extending along the top. The
.need area would be posted and gates kept locked. In addition to fencing,
legal actions would be taken to attach deed restrictions that would control
future access and land use in the event the Site property is transferred to
another owner.
Institutional controls for affected groundwater beneath and downgradient of
the Site would consist of periodic groundwater monitoring as described in
Alternative 1 and measures that would limit exposure to groundwater from
the Site. Access to Site groundwater would be restricted by deed
restrictions that would preclude future residential use of the groundwater
by the current or subsequent land owners. Long-term monitoring at the Site
would be conducted as described in Alternative 1 (Mo Action).
Capital Costst $ 152,000.00
Annual O&M Costss $ 129,000.00 .
Total Present Worth Costst $ 2,130,000.00
7.2.3 Alternative 3t Groundwater Extraction t Trea+T'ent
This alternative combines the options described in Alternative 2
(Institutional Controls, with operation of the existing (or modified)
groundwater extraction and treatment program. This alternative includes
the following components!
• long term monitoring as presented in Alternative 1;
• institutional controls as presented in Alternative 2 for the
known contaminated portions of the aquifer)
• groundwater flow containment and extraction;
• groundwater treatment; and
• discharge effluent to POTW.
Groundwater flow containment would initially be accomplished by using the
currently operating fourteen (14) recovery wells (KW-4 through RW-17) that
are currently operating at the Site. The system will operate for
approximately thirty (30) years. The wells extend in an arc from south to
north approximately parallel to the eastern property line. During the
Remedial Design/Remedial Action phases of the project, the need for
upgrades to the existing system, including the addition of bedrock
extraction wells will be evaluated. In the interim, recovery wells RW-2
and RW-3 will be upgraded and added to the existing jet pump extraction
system. The existing well locations are shown in Plata 1-1. Currently,
the wells (RN-4 through RW-"7) extract aproximately 30 gallons per minute
(gpm).
The volatile organic contain, .ants of concern at the Site have been shown to
:: effectively^emoved from groundwater by air stripping. Those inorganic
: ':'2s not addressed by the on-Site treatment system will receive treatment
at the POTW. Para-Chem has an operating permit (Permit No. IO-1182) for
discharge of treated water to the Western Carolina Regional Sewer Authority
(WCRSA). WCRSA requires monthly monitoring of discharge to evaluate
-------
44
treatment system performance. Monthly sampling is expected to continue
-der this treatment alternative in accordance with WCRSA pretreatment
luirements. Treatment of groundwater by air stripping Is currently
—feting WCRSA permit requirements.
After treatment, groundwater extracted from beneath the Site is piped to
the Western Carolina Regional Sewer Authority (WCRSA) Onrbln Creek plant.
The WCRSA currently requires that Para-Chem effluent be monitored on a
monthly basis for volatile organic compounds and cine. The treatment
program proposed under this alternative would continue those analyses, as
prescribed by WCRSA.
In addition to groundwater extraction and treatment from the saprolite, a
minimum of two recovery wells will be Installed within the shallow bedrock
zone adjacent to bedrock borings B-l and B-8. EPA may require the
conversion of several of the bedrock borings to monitoring points. Bach
interval containing detectable concentrations of VOCs will be monitored.
The rationale for the dual (2) groundwater program of monitoring and
extraction is based on two considerationst remediating the cones with the
highest concentrations of contaminants; and, controlling the hydraulic
effects of drawdown. The need for additional wells will be determined
based on evaluation of the system's effectiveness and monitoring results.
Capital Costss $ 630,000.00
Annual O&M Costss $ 281,000.00
Total Present Worth Costss $ 4,944,000.00
{. 4 Alternative 41 Capping of Sludge with Groundwater Treatment
.uis alternative combines Alternative 2 (Institutional Controls) and the
groundwater treatment program of Alternative 3 with Installation of an
impermeable cap over the concrete settling basin. Sludge disposal areas
will be investigated during the Remedial Design. Sludge identified during
the investigation will be consolidated in the area of the concrete settling
basin prior to capping. The purpose of capping is to reduce contact by
receptor populations and the environment with waste contaminants found at
the Site. This reduction would be accomplished by minimising vertical
migration of waste contaminants, preventing erosion of affected Site
materials, and providing a barrier to direct contact. The cap would cover
the sludge containing organic and inorganic compounds at concentrations
that exceed the sludge remedial action targets. The concrete settling
basin has a surface area of approximately 250 square feet. Figure 6-4
shows the plan view of a conceptual layout for this alternative.
An impermeable cap would minimise contact between percolating water and
waste contaminants, thereby reducing the potential for migration of waste
contaminants to the groundwater. In addition, a cap installed over the
affected materials would prevent erosion of waste contaminants by wind or
surface water runoff. Adjacent surface areas would be graded, as
necessary, to divert surface drainage around and away from the contained
solids. A containment cover of this type would require periodic
maintenance and inspection.
• >ital Costsi** $ 716,000.00
aual O&M Costst $ ' 302,000.00
Total Present Worth Costss $ 5,358,000.00
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45
7.2. S Alternative 51 Bxeavat -. of Sludge with Groundwater Treatment
:ernative 5 consists of the groundwater treatment program presented in
.tentative 3 with removal of sludge with concentrations of contamination
exceeding remediation goals. The known areas include the concrete settling
basin and locations near CS-06, HA-13, and HA-16. This alternative
includes two options for sludge removals a) excavation; and, b) pumping.
This alternative also includes three options for sludge treatment/disposalt
a) off-Site treatment by thermal destruction; b) off-Site disposal of the
sludge in a secure landfill; and c) on-Slte biological treatment of the
sludge in the existing waste treatment unit. Treatment by thermal
destruction using a rotary kiln was selected on the basis of commercial
availability and a history of prior application to similar wastes.
Biological treatment in the on-Site activated sludge unit was selected on
the basis of availability, ease of implementation, and a history of prior
application to similar wastes.
For sludge that may be affecting groundwater quality, the first step in
this alternative would include removal from the concrete settling basin and
from areas near HA-13, HA-16, and other areas that may be identified during
future investigations. Following sludge removal the in-ground concrete
tank will be removed and sampled to evaluate proper disposal options.
Confirmatory testing will be conducted at the limits of the excavation.
If adjacent soils exceed remediation target concentrations for protection
of groundwater, these soil will be removed. Alternative Sa of this
alternative, affected soils, if present, would be excavated and treated by
thermal destruction. The solid wastes requiring treatment are estimated to
>nsist of approximately 200 in-place cubic yards of affected sludge. The
:ent of subsurface excavation would be determined by collection and
~aalysis of confirmation samples from underlying soil after the removal of
the sludge and visibly-affected soil.
Sludge may require dewatering prior to implementation of thermal
destruction or land disposal. However, even if the moisture content is
high, the relatively small volume of material might eliminate the need for
special handling prior to treatment or disposal. High moisture content
will be required for implementation of Alternative 5c (biological
treatment) alternative. Bach treatment facility evaluated during remedial
design will be fully operational and in compliance with the applicable
regulations. Disposal of treatment residuals would be in accordance with
facility permit requirements.
Bach of the treatment process options could require preprocessing of the
solids to remove debris and to reduce the particle sice of the waste
matrix. At other Sites where larger volumes of heterogenous wastes are
excavated for treatment, a one-percent rejection rate is often used to
obtain more accurate cost estimates. However, since the quantity of
material in and adjacent to the concrete settling basin is comparatively
small, the cost and economic analysis of this alternative assumes that the
entire mass of sludge will be treated.
Clean backfill would be placed in the excavated concrete settling basin.
The graded cover would be sown with shallow-rooted grasses to reduce
ision. The restored area would receive periodic maintenance and
jpection.
The selected waste transporter required for Alternatives 5a and 5b must be
in compliance with applicable federal and state environmental and public
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46
health statute* applicable to the waste contaminant* identified at the
"«te. if necessary, RCRA manifests, as required under 40 C.F.R. Parts 262
i 263, would be completed for all wastes shipped off-Site. Vehicles
.ansporting from the Site would be licensed by the Department of
Transportation (DOT) and would display the proper DOT placard.
Option Sat Incineration
Capital Costs * $ 1,792,000.00
Annual O&M Costs s $ 281,000.00
Total Present Worth Costs s $ 6,106,000.00
Option 5bs Off -Site Land Disposal
Capital Costs i $ 1,271,000.00
Annual O&M Costs s $ 281,000.00
Total Present Worth Costs s $ 5,585,000.00
Option Set On-Site Biological Treatment
Capital Costs t $ 1,184,000.00
Annual O&M Costs s $ 281,000.00
Total Present Worth Costs: $ 5,498,000.00
~ 0 SUMMARY OP COMPARATIVE ANALYSIS OP ALTERNATIVES
.ae five (5) alternatives were evaluated based upon the nine (9) criteria
set forth in 40 C.F.R. S 300.430(«) (i) of the HCP. In this section , brief
summaries of how the alternatives were judged against these nine criteria
are presented. Also included is a description of the criteria. For ease
of reference, the five (5) alternatives considered are listed in Table 8-1.
8.1 Threshold Criteria
Two (2) threshold criteria must be achieved by a remedial alternative
before it can be selected.
1. Overall protection of h"1*"**! health and the enviropn*ent addresses
whether the alternative will adequately protect human health and the
environment from the risks posed by the Site. Included in judgement by
this criterion is an assessment of how and whether the risks will be
properly eliminated, reduced, or controlled through treatment, engineering
controls, and/or institutional controls.
Alternative 1 (HO Action) would not achieve protection of human health and
the environment. Risks identified in the Baseline Risk Assessment would
continue to exist. Alternative 2 (Institutional Controls) would produce
limited protection by preventing human contact with contaminated
oroundwater and sludge/soil by restricting aquifer and property usage;
Hii^TBver, the potential threat to the on-Site stream from contaminated
'*: 'aundwater discharge would remain. Alternative 3 (Gronndwater Treatment)
would achieve a moderate degree of protection. Further migration of the
groundwater contaminants would be prevented, and groundwater extracted at
the leading plume edge would be treated prior to discharge to WCRSA.
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47
Alternative 4 (Capping of Sludge with Groundwater Treatment) would provide
••ditional protection by reducing rainfall infiltration through the
itaminated sludge and/or coil, thereby reducing the amount of
—
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48
2. Reduction of toxiclt(Yf jK>*flilit^. pr voJBB? addresses the anticipated
-*rformance of the treatment technologies that an alternative nay employ.
f 1986 amendment to CBRCLA, the Superfund Amendments and Reauthorization
-c (SARA), directs that, when possible, BPA should choose a treatment
process that permanently reduces the level of toxicity of Site
contaminants, eliminates or reduces their migration away from the Site,
and/or reduces their volume on a Site.
TABLE 8-1
REMEDIAL ALTERNATIVES COST
Description
1
2
3
4
5
Mo Action
Institutional Controls
Gronndwater Extraction fc Treatment
Cap Sludge with Groundwater
Extraction t Treatment
Excavation of Sludge with Ground-
Water Extraction & Treatment
5a Incineration
Sb Off-Site Landfill Disposal
5c Biological Treatment
Cost
$2,108,000
$2,130,000
$4,944,000
$5,385,000
$6,106,000
$5,585,000
$5,498,000
Alternatives 1 (Ho Action) and 2 (Institutional Controls) would not meet
this criterion since no treatment would occur. Alternatives 3 (Groundwater
Treatment) and 4 (Capping of Sludge and Groundwater Treatment) would
achieve varying degrees of mobility, toxicity and volume reduction.
Alternative 5 (Excavation of Sludge and Groundwater Treatment) would
achieve the greatest degree of reduction of toxicity, mobility, and volume
through excavation .and treatment of sludge and soil which is acting as a
continuing source of contamination to gronndwater.
3. Short-term effectiveness refers to the length of time needed to achieve
protection, and the potential for adverse effects to human health or the
environment posed by implementation of the remedy, until the remediation
goals are achieved.
Of all the alternatives that achieve ARARs, Alternative 3 (Gronndwater
Treatment) affords the greatest level of short-term protection because it
: tsents the lo&st disturbance to the Site. The remaining alternatives
;uld release amounts of volatile emissions during implementation but
should be manageable through standard construction practices.
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4. implementabilltv considers the technical and administrative feasibility
-* an alternative, including the availability of materials and services
:essary for implementation.
Implementation is not a concern for Alternative 1 (No Action), since no
actions would be implemented. Alternative 2 (Institutional Controls) would
require the least effort to implement as it only requires institutional
controls . The remaining alternatives, Alternatives 3 (Groundwater
Treatment), 4 (Capping of Sludge and Groundwater Treatment) and 5
(Excavation of Sludge and Groundwater Treatment), are implementable using
proven technologies. Alternative 5c (Biological Treatment of Sludge) would
require a treatability study to determine the effectiveness of biological
treatment of Site-specific contaminated sludge.
5. Cost includes both the capital (investment) costs to implement an
alternative, plus the long-term O&M expenditures applied over a projected
period of operation. The total present worth cost for each of the five (5)
alternatives is presented in Table 8-1.
8.3 Modifying Criteria
State acceptance and community acceptance are two (2) additional criteria
that are considered in selecting a remedy, once public comment has been
received on the Proposed Plan.
1. State acceptancet The State of South Carolina concurs with the
•"lection of Alternative 5c, the preferred alternative outlined in the
iposed plan. South Carolina's letter of concurrence is provided in
_^pendLx A to this ROD.
2. Community acceptance During the Proposed Plan public meeting, held on
June 29, 1993, EPA presented its preferred alternative, Alternative 5c, for
the remediation of the Site. The public comment period opened on June 22,
1993, and closed on July 21, 1993. Mo written comments were received
concerning the Para-Cham Southern Site. Comments expressed at the public
meeting are addressed in the Responsiveness Summary attached as Appendix B
to this ROD.
9.0 Tm* SBIiBC'l'ED REMEDY
Based upon consideration of the requirements of CERCLA, the NCP, the
detailed analysis of alternatives and public and state comments, EPA has
selected a remedy that addresses soil and groundwater contamination at this
Site. At the completion of this remedy, the risk remaining at this Site
will be within BPA's acceptable risk range of 1 x 10"* to 1 x 10"4, which is
considered protective of human health and the environment. The selected.
remedy for this Site 1st
Alternative Set Excavation and Biological Treatment of Sludge
combined with Groundwater Extraction and Treatment
Total Present Worth Costst $5,498,000.00
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50
9.1 Source Control
irce control remediation will address the contaminated sludge and/or
,ils at the Site. Sludge excavation involves the removal of affected
materials from an identified area followed by treatment or disposal. The
purpose of excavation is to physically remove the source of waste
contaminants to prevent potential future migration of wastes. This
technology is viable and effective in minimizing future impact to
groundwater* assuming that all significant sources of waste contaminants
are located and excavated. The solid wastes requiring treatment are
estimated to consist of approximately 200 in-place cubic yards of affected
sludge.
The major components of source control include the excavation of
contaminated sludge and/or soil until the remaining materials achieve the
concentrations established as performance standards as described in Section
9.3 of this ROD. Following sludge removal the in-ground concrete tank will
be removed and sampled to evaluate proper disposal options. Subsurface
soils adjacent to sludge may also be contaminated and therefore violate the
performance standards. The extent of subsurface soil excavation would be
determined by collection and analysis of confirmation samples from
underlying soil after the removal of the sludge and visibly-affected soil.
The subsurface soil shall be excavated until the remaining soil achieves
the performance standards or the water table is encountered.
Clean backfill would be placed in the excavated concrete settling basin.
The graded cover would be sown with shallow-rooted grasses to reduce
•~osion. The restored area would receive periodic maintenance and
tpection.
The excavated sludge will be treated .through the use of the operational on-
Site waste treatment unit. This unit will be used to biologically degrade
the organic chemicals present in the sludge. The unit will be required to
continue to meet the requirements of.all applicable federal, state, or
local permit conditions. The system typically consists of the following
unitsi
• Equalization tank
• Activated Sludge unit
• Settling unit
• POTW disposal
This treatment process could require preprocessing of the solids to remove
debris and to reduce the particle size of the waste matrix. Additionally a
high moisture content will be required for implementation of this
alternative. Sludge would be added incrementally to the existing process
waste stream following any necessary pretreataent process.
The operating waste treatment system is currently treating volatile organic
compounds present in the process waste stream. The compound 1,1,1-TCA. is
•; > only contanlnant of concern not present in the current waste stream.
; .jcific system details for biological destruction of all contaminants of
concern within the available treatment unit would be developed as a part of
the remedial design phase of the project.
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Adjacent contaminated soil will be transported to a regulated facility.
~*«is decision is based on the small volume of contaminated soil expected at
Is Site. Any portions of the contaminated sludge and related material
.*at is unsuitable for biological treatment will also be sent to a
regulated facility and disposed of in compliance with all ARARs. If
necessary, excavated wastes would be treated on-Site using stabilisation
technologies in order to meet the appropriate land disposal treatment
requirements. Excavated material would then be transported by a licensed
hazardous-waste transporter to an off-Site hazardous waste disposal
facility permitted to dispose of RCRA hazardous wastes. Bach treatment
facility evaluated during remedial design will be fully operational and in
compliance with the applicable regulations. Disposal of treatment
residuals would be in accordance with facility permit requirements.
The selected waste transporter must be in compliance with applicable
federal and state ARARs identified for the waste contaminants identified at
the Site. If necessary, RCRA manifests, as required under 40 C.F.R. Parts
262 and 263, would be completed for all wastes shipped off-Site. Vehicles
transporting from the Site would be licensed by the Department of
Transportation (DOT) and would display the proper DOT placard.
9.1.1 Sludae/Soi.1 Performance Standards
Protective levels of subsurface sludge and soil contaminants were based on
the results of a leaching model using Site-specific information conducted
in the FS. Three sludge samples exhibited concentrations in excess of the
'-•vels for 1,1-Dichloroethene, Tetrachloroethene, Toluene, and 1,1,1-
Lchloroethane. Some of the RI subsurface soil samples did not exceed
.^ese standards; however, performance standards were established as a
contingency to allow the remedial action to proceed in the event subsurface
contaminant concentrations exceeding these standards are encountered.
There are no established federal or state standards for acceptable levels
of contaminants in subsurface sludges and soils.
The levels presented in the following section will be established as
performance standards for this Site. The initial performance standards as
presented in the FS and proposed plan included calculation errors. These
corrections have been made and are incorporated into Table 9-1 and do not
create a different level of performance.
The standards outlined in this section comprise the performance standards
defining successful implementation of this portion of the remedy. The
Performance Standards for this component of the selected remedy include the
following excavation and treatment standards!
9.1.2 Excavation and Traa*""
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TABLE 9-1
SLUDGE/SOIL PERFORMANCE STANDARDS
Contaminants
Acetone
1, 1-Dichloroethene
1 , 2-Dichloroethene
Tetrachloroethene
Toluene
1,1, 1-Trichloroethane
Trichloroethylene
Maximum COT
Detected
Sludge
ND
350
3.6
120
590
14,000
3.4
icentration
(mg/kg)
Soil
0.14
0.015
ND
0.110
0.009
1.1
0.001
Remediation
Goal
(mg/kg)
4687
2.6
446
.446
122.7
10.5
1.7
Sludge/Soil Remediation Goals were based on leaching potential
calculated by the PESTAN model.
9.1.3 ADD
or Relevant and Appropriate Reouireingnts ( ARARs \
ARARs originate from applicable requirements , intended to definitely and .
specifically apply to a remedial action; or relevant and appropriate
requirements, which, while not intended to apply to the specific situation
in question, EPA judges to be applicable to a remedial action. In
lit ion, when establishing criteria for ensuring the proper implementation
a remedial action, EPA and the State have agreed to consider a number of
procedures that are not legally binding.
Applicable Requirements. Soil remediation shall comply with all applicable
portions of the following Federal and State of South Carolina regulationst
49 C.F.R. Parts 107, 171-179, promulgated under the authority, of the
Hazardous Materials Transportation Act. Regulates the labelling,
packaging, placarding, and transport of hazardous materials off-Site.
40 C.F.R. Parts 261, 262 (Subparts A-D), 263, 264, and 268, promulgated
under the authority of the Resource Conservation and Recovery Act. These
regulations govern the identification, transportation, manifestation, and
land disposal .restriction requirements of hazardous wastes in addition to
closure and groundwater monitoring requirements. If the contaminated soils
fail TCLP, the material will be handled and disposed of as hazardous
waste. To determine if the materials which fail TCLP are subject to land
disposal restrictions in 40 C.F.R. Part 268, EP toxicity test will be
performed as appropriate. Should the materials fail the BP Toxicity test,
the material will be subject to the referenced land disposal restrictions.
However, if BP toxicity tests are performed and the contaminated soils do
not exceed BP toxicity limits, then the land disposal restrictions in 40
C.F.R. Part 268 will not apply, even though the contaminated soils fail
.' -LP. In the fjrent that the Site soils requiring remediation do not test
jardous (i.e., do not fail TCLP), the regulations listed here will be
Considered relevant and appropriate rather than applicable.
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S3
SCOmat 61-79.124, .261, .262, .263 and .268, South Carolina Hazardous Waste
"nnagement Regulations, promulgated pursuant to the Hazardous Waste
lagement Act, SC Code of Laws, 1976, as amended. Establishes criteria
,c identifying and handling hazardous wastes, as well as land disposal
restrictions. These regulations will also become relevant and appropriate
in the event that the soils requiring remediation do not prove to be
hazardous, as described in the above paragraph.
Relevant and Appropriate Requirements. The following regulations are
•relevant and appropriate* to sludge and/or soil remedial actions at the
Site. Applicability of these air quality control regulat on* is due to the
..otential for release of harmful particulates (metals) or VOCs during soil
excavation and handling activities.
40 C.F.R. Parts 60 and 61, promulgated under the authority of the Clean Air
Act. Included are the National Emissions Standards for Hazardous Air
Pollutants (NESHAPs). Ambient air quality standards and standards for •
emissions to the atmosphere fall under these regulations.
SC Reg. 61-62, South Carolina Air Pollution Control Regulations and
Standards, promulgated pursuant to the S.C. Pollution Control Act, SC Code
of Laws, 1976, as amended. Establishes limits for emissions of hazardous
air pollutants and particulate matter, and establishes acceptable ambient
air quality standards within South Carolina.
9.2 Groundwater
. jundwater remediation will address the contaminated groundwater at the
_.te. Groundwater remediation will include the extraction of contaminated
groundwater, treatment, and discharge to WCRSA.
The major components of groundwater remediation to be implemented include
the operation of the existing (or modified) groundwater extraction and
treatment program. The existing operation consists of the extraction and
treatment by airstripping of contaminated groundwater at the Site. This
will include the following componentst
• long term monitoring as presented in Alternative 1,
• institutional controls as presented in Alternative 2,
• groundwater flow containment and extraction,
• groundwater treatment, and
• discharge of treated water to WCRSA in accordance with all
applicable regulations and other Performance Standards.
The extraction, treatment, and discharge of contaminated groundwater would
initially be accomplished by using the fourteen (14) recovery wells (RW-4
through RW-17) that are currently operating at the Site. The system will
irate for approximately thirty (30) years. The wells extend in an arc
: ;jm south to north approximately parallel to the eastern property line.
During the Remedial Design/Remedial Action phases of the project, the need
for upgrades to the existing system, including the addition of bedrock
extraction wells will be evaluated. In the interim, recovery wells RW-2
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54
and RW-3 will be upgraded and added to the existing jet pump extraction
-"stem. The well locations are shown in Figure 6-3. Currently, the wells
f-4 through RW-17) extract approximately thirty (30) gallons per minute
. ..pn). During the Remedial Design phase, the air emissions from the
stripper exhaust will be estimated and the impact to human health and the
environment will be assessed. The use of a control technology (e.g. carbon
adsorption) may be necessary if warranted by the assessment.
Para-Chem has an operating permit (10-1182) for discharge of treated water
to the Western Carolina Regional Sewer Authority (WCRSA). WCRSA requires
monthly monitoring of discharge to evaluate treatment system performance.
The authority currently requires that Para-Chem effluent be monitored on a
monthly basis for volatile organic compounds and cine. The treatment
program proposed under this alternative would continue those analyses, as
prescribed by WCRSA, in addition to any other monitoring which may be
required by WCRSA. • •
In addition to groundwater extraction and treatment from the saprolite,
two (2) recovery wells will be installed within the shallow bedrock cone
adjacent to bedrock borings B-l and B-8. EPA may require the conversion
of several of the bedrock borings to monitoring points. Bach interval
containing detectable concentrations of VOCs will be monitored.
9.2.1 Groundwater Performance Standards
In the FS, groundwater concentrations protective of human health and the
"vironment were calculated based on the Site-specific risk calculations
m the Baseline Risk Assessment. Some of the remediation goals are
--tabliahed in cases where there is no MCL for a particular contaminant.
Specific contaminants for which health-based goals were established were
acetone, 2-butanone, chloroform, and 1,1-dichloroethane. The remediation
goal for 1,1,2-trichloroethane are based on the MCLG for this contaminant.
Aluminum, manganese, and cine remediation goals were based on secondary
HCLs for these contaminants.
The groundwater remediation goals in Table 9-2 below shall be the
performance standards for groundwater treatment. Groundwater shall be
treated until the following maximum concentration levels are attained .
As part of the remedial design, sufficient additional groundwater and
surface water data shall be collected to achieve the following objectivest
A. Verify the presence or absence of contamination beyond the
existing series of recovery wells. This will include identifying
areas of contaminated groundwater that the existing system will not .
adequately remediate. Capture sone modeling will be performed using
several different scenarios.
B. Confirm the contributing source of contamination in the surface
water within the on-Site tributary of Big Durbin Creek.
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TABLE 9-2
>ROUNDWATBR PERFORMANCE STANDARDS
Contaminant
Concentration
Detected (mg/1)
lation
Goal
(mg/1)
Source
Organic Compounds
Acetone
Benzene
2-Butanone
Chloroform
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
1,2-Dichloroethene
Methylene Chloride
Toluene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
Trichloroethene
atrachloroethene
ylene (total).
noroanlc Compounds
Aluminun
Arsenic
Manganese
Zinc
8.9
0.005*
480*
0.022*
1.5
6.0*
7.9*
2.T
1.1*
11
16
0.015*
1.8
0.058
0.012
8.55
0.0034-
19.2
10
0.52
0.005
0.60
0.0005*
0.78
0.005
0.007
0.07
0.005
1
0.2
0.003
0.005
0.005
10
0.05
0.05
0.05
5
A
B
A
A
A
B
B
B
B
B
B
C
B
B
B
D
B
D
D
SOURCES OF REMEDIATION LEVELS
A - Health-Based Remediation Level (HI>1)
B - MCL
C - MCLG
D - Secondary MCL
* Denotes contaminant concentrations from previous sampling
investigation* (RI Workplan Appendix H) at which concentrations exceeded
the performance standard.
** This value is below the current practical quantitation limit (PQL) set
at 0.001 mg/1 for chloroform. Therefore the acceptable performance
standard will be set at the PQL at the time of analysis until the PQL is
equivalent to 0.0005 mg/1.
Attainment of these objectives must be accomplished during the first
nortion of remedial design, so that design of the extraction and treatment
-;v^»tem has, as*3.ts basis, an accurate conceptual model of Site conditions.
;Afirmation of the extent of contamination will also require collection of
further information and data for characterizing the specific hydrogeology
of the Site, and will include modelling as appropriate.
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56
n 2.3 AxrnHcabla or Relevant and Jtcoronriate ReauirfunantB
..ARs originate from applicable requirements, intended to definitely and
specifically apply to a remedial action; or relevant and appropriate
requirements, which, while not intended to apply to the specific situation
in question, EPA judges to be applicable to a remedial action. In
addition, when establishing criteria for ensuring the proper implementation
of a remedial action, EPA and the State'have agreed to consider a number
of procedures that are not legally binding.
Groundwater remediation shall comply with all applicable portions of the
following federal and State of South Carolina regulations*
40 C.F.R. Parts 60 and 61, promulgated under the authority of the Clean Air
Act. Included are the National Emissions Standards for Hazardous Air
Pollutants (HBSHAPe). Standards for emissions to the atmosphere fall under
these regulations. Applicable to the air stripping unit to be used for
groundwater treatment.
SC Rag. 61-58, South Carolina Primary Drinking Water Regulations,
promulgated pursuant to the Safe Drinking Water Act, SC Code of Laws, 1976,
as amended. These regulations are similar to the federal regulations
described above, and are relevant and appropriate as remediation criteria
for the same reasons set forth above.
SC Reg. 61-62, South Carolina Air Pollution Control Regulations and
"•andards, promulgated pursuant to the Pollution Control Act, SC Code of
jfs, 1976, as amended. Establishes limits for emissions of hazardous air
c-^llutants and particulate natter, and establishes acceptable ambient air
quality standards within South Carolina. This regulation is applicable in
the same manner as the federal regulation cited above.
40 C.P.R. Part 122, 125, 129, 133 and 136, CWA Discharge Limitations (CWA $
301), promulgated under the authority of the Clean Water Act. Applicable
to any point discharges of wastewaters to waters of the United States.
Applicable to discharge of treated waters.
40 C.P.R. S 403.5, CWA Pretreataent Standards (CWA S 307), promulgated
under the authority of the Clean Water Act. Regulates discharges of water
to POTWS.
SC Reg. 61-68, South Carolina Water Classifications and Standards,
promulgated pursuant to the Pollution Control Act, SC Code of Laws, 1976,
as amended. These regulations establish classifications for water use, and
set numerical standards for protecting state waters.
SC Reg. 61-71, South Carolina Well Standards and Regulations, promulgated
under to the Safe Drinking Water Act, SC Code of Laws, 1976, as amended.
Standards for well construction, location and abandonment are established
for remedial work at environmental or hazardous waste Sites.
*0 C.P.R. Part 131, Ambient Water Quality Criteria (CWA S 304), promulgated
i:;: ler the authority of the Clean Water Act. Sets numerical criteria for
iient water quality based on toxicity to aquatic organisms and human
health.
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57
40 C.P.R. Parts 141-143, National Primary and Secondary Drinking Water
"*-.andards, promulgated under the authority of the Clean Water Act. These
julations establish acceptable maximum levels of numerous substances in
. *0>lic drinking water supplies, whether publicly owned or from other
sources such as groundwater. w«y<»mn» contaminant Level* (MCLs) and Maximum
Contaminant Level Goals (MCLGs) are specifically identified in the NCP as
remedial action objectives for groundwaters that are current or potential
sources of drinking water supply (NCP 40 C.F.R. S 300.430(a)(l)(ii) (P).
Therefore, MCLs and MCLGs are relevant and appropriate as criteria for
groundwater remediation at this Site.
Various to be considered (TBC) materials were utilized in the Baseline Risk
Assessment and in the Feasibility Study. Because cleanup standards were
established based on these documents, they are considered TBC. In the
Baseline Risk Assessment, TBC material included information concerning
toxicity of, and exposure to, Site contaminants. TBC material included the
Integrated R k Information System (IRIS), Health Effects sessment
Summary Tabl (HEAST), and other EPA guidance as specific in the Baseline
Risk Assessment. Other TBC material include the following
Revised Procedures for Planning and Implementing Off-Site Response Actions,
OSWER Directive 9834.11, November 1987. This directive, often referred to
as "the off-Site policy,• requires EPA personnel to take certain measures
before CBRCLA wastes are sent to any facility for treatment, storage, or
disposal. EPA personnel must verify that the facility to be used is
operating in compliance with S 3004 and S 3005 of RCRA, as well as all
ther federal and state regulations and requirements. Also, the permit
-der which the facility operates must be checked to ensure that it
thorizes (•!) the acceptance of the type of wastes to be sent, and (2) the
_/pe of treatment to be performed on the wastes.
40 C.F.R. Part 50, promulgated under the authority of the Clean Air Act.
This regulation includes the National Ambient Air Quality Standards
(NAAQS), and establishes a national baseline of ambient air quality levels.
The state regulation which implements this regulation, South Carolina Reg.
62-61, is applicable to the source control portion of the remedy.
'uidelines for Ground Water Use and Classification, EPA Ground Water
protection Strategy, U.S. EPA,. 1986. This document outlines EPA's policy
of considering a Site's groundwater classification in evaluating possible
remedial response actions. As described under Section 1.4, the groundwater
at the Site is classified by EPA as Class I IB and by South Carolina as
Class GB groundwater, indicating its potential as a source of drinking
water.
National Oceanic and Atmospheric Administration (NOAA) ER-L/ER-M Values.
These guidelines were developed as screening criteria for sediment
contamination in surface water bodies, and are based on toxicity to aquatic
life.
40 C.F.R. Part 50, National Ambient Air Quality Standards (NAAQS),
promulgated under the authority of the Clean Air Act. This regulation
includes the National Ambient Air Quality Standards (NAAQS), and
-.ablishes a national baseline of ambient air quality levels. The state
•^ulation which implements this regulation, South Carolina Reg. 62-61, is
applicable to the groundwater portion of the remedy.
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58
Clean Air Act, S 501 and 502, 1990 CAA Amendments, 42 U.8.C.
' 7661 and S 7661(a). The amendments will require that all "major sources•
I certain other sources regulated under the CAA obtain operating permits.
.though CERCLA S 121(e) exempts this remedy from requiring such a permit,
air stripping at this Site may have to comply with any substantive
standards associated with such permits. Regulations have been proposed,
but not promulgated, for the operating permit program.
Remedial design often includes the discovery and use of unforeseeable, but
necessary, requirements, which result from the planning and investigation
inherent in the design process itself. Therefore, during design of the
source control or groundwater component of the selected remedy, EPA may,
through a formal ROD modification process such as an Explanation of
Significant Differences or a ROD Amendment, elect to designate further
ARARs which are applicable, or relevant and appropriate, to this remedy.
Discharge of treated groundwater to the POTH shall comply with all
applicable HCRSA industrial pretreatment standards, as well as any other
effluent standards or limits established by EPA.
9.4 Compliance Testing
The selected remedy will include groundwater extraction for an estimated
period, during which the system's performance will be carefully monitored
on a regular basis and adjusted as warranted by the performance data
collected during operation. Modification may include any or all of the
"Allowingi
* at individual wells where cleanup goals have been attained, pumping
may be discontinued;
* alternating pumping at wells to eliminate stagnation points;
* pulse pumping to allow aquifer equilibration and encourage adsorbed
contaminants to partition into groundwater; and
* installation of additional extraction wells to facilitate or
accelerate cleanup of the contaminant pit
To insure that cleanup goals continue to be maintained, the aquifer will be
monitored at those wells where pumping has ceased on a. regular periodic
basis, following discontinuation of groundwater extraction. The intervals
between groundwater sampling/analysis events will be established in the
Remedial Action Work Plan.
The decision to invoke any or all of these measures may be made during a
periodic review of the remedial action (Five Tear Review), which will occur
at five year intervals in accordance with CERCLA Section 121(c), 42 U.S.C.
S 9621(c).
9.5 Monitor Site Gronndwater flfld Surface Water
"::';::;.::: ^
ginning with initiation of the remedial design, groundwater and surface
water samples shall be collected and analysed on a regular quarterly
schedule. Analytical parameters for groundwater and surface water samples
will include the known Site contaminants of concern. The specific wells to
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be sampled and methodology for sample collection will be determined during
••••sign. Surface water samples will be collected, as a minimum, from the
lamed tributary at one upstream location and one downstream location as
. .icessary to monitor the contamination. The analytical data generated from
the quarterly sampling events will be used to track the concentrations and
movement of groundwater contaminants until a long-term Site monitoring plan
is implemented in the remedial action phase.
10.0 STATUTORY DETERMINATIONS
The selected remedy for this Site meets the statutory requirements set
forth at Section 121(b)(l) of CBRCLA, 42 U.S.C. S 9621(b)(l). This section
states that the remedy must protect human health and the environment; meet
ARARs (unless waived); be cost-effective; use permanent solutions, and
alternative treatment technologies or resource recovery technologies to the
maximum extent practicable; and finally, wherever feasible, employ
treatment to reduce the toxicity, mobility or volume of the contaminants.
The following section discusses how the remedy fulfills these requirements.
Protection of^ ftuinan health and the environment! The selected remedy will
remove the human health risks from contact with contaminated Site sludge
and soils. The groundwater remediation system will extract and treat
contaminated groundwater, thereby reducing and eventually removing the
future risks to human health which could result from ingestion of or
contact with groundwater.
~-«mpliance with ARARs t The selected remedy will meet ARARa, which are
ited in Section 9.1.2 of this ROD.
Cost effectiveness i Among the alternatives that are protective of human
health and the environment and comply with ARARs, the selected alternative
is the most cost-effective choice because it uses a treatment technology to
address the sludge which is acting as a source of contamination for the
groundwater. This approach will reduce the volume of groundwater that will
need to be treated. The selected alternative is the most cost-effective
choice because it uses a well proven widely-used treatment method for which
costs can be reliably predicted (air stripping), and because the use of the
POTW option is the most cost-effective means to dispose of the treated
groundwater.
Utilization of per|**T.ernatives considered, and utilizes the most cost-effective option for
jposal of sludge, soil, and treated groundwater. The selected sludge and
soil remedial action is the most practical and easily implemented
alternative, given the relatively small volume of sludge requiring
remediation (approximately 200 cubic yards).
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60
erence for treatment as a principal r*""edv el^m^nt t The proposed
;ernative will fulfill the preference for treatment as a principal
.ement through the extraction and treatment of contaminated groundwater in
addition to the excavation and biological treatment of sludge.
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