EPA Superfund
Record of Decision:
Hercules 009 Landfill Site,
(O.U. 1) Brunswick, GA
3/25/1993
PB94-964070
EPA/ROD/R04-93/144
February 1995
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50272-101
REPORT DOCUMENTATION 11. REPORT NO. '2. 3. Recipient. Acc8uIon No.
PAGE EPA/ROD/R04-93/144
4. Titl. and Subtitle 5. R.port Date
SUPERFUND RECORD OF DECISION 03/25/93
Hercules 009 Landfill, GA 6.
Second Remedial Action - Final
7. Author(s) 8. Performing Organization Rlpt. No.
9. Performing Organization Name and Add.... 10 Project Ta8lclWork Unit No.
11. Contracl(C) or Grant(G) No.
(C)
- (G)
12. Sponsoring Organization Name and Add,... 13. Typa of Report & Period eover8d
U.S. Environmental Protection Agency
401 M Street, S.W. 800/800
Washington, D.C. 20460 14.
15. Supplementary Notel
PB94-964070
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16. Abstract (Umlt: 200 words)
The 16.5-acre Hercules 009 Landfill site is an inactive industrial landfill located in
Brunswick, Glynn County, Georgia. Land use in the area is predeminantly commercial and
residential, with a shopping mall, bank, and restaurant located approximately 1,000
feet north of the site. From 1948 to 1980, Hercules manufactured toxaphene, an
agricultural pesticide used to control boll weevils, ticks, and mites on cattle. Under
a State permit, Hercules used seven acres at the northern end of the site, known as the
009 landfill, to dispose of approximately 33,000 yd3 of wastewater sludge from the
production of toxaphene, empty toxaphene product drums, and toxaphene-contaminated
glassware, rubble, and trash. The landf ill was constructed as six cells, which
reportedly were lined with a soil bentonite clay mixture across the bottom and along
the bermed walls. The thickness of the toxaphene sludge disposed of in these cells was
reported to be six to seven feet. Typically, the wastewater sludge was disposed of
directly in the landfill; powever, occasionally it was staged near the southeast c'orner
of the landfill prior to disposal. In 1980, as a result of a State investigation which
revealed toxaphene in soil and water samples from the drainage ditches. around the site,
Hercules' permit was canceled, and the State ordered the landfill to be closed. In
(See Attached Page)
17. Document Analysis a. Deacrlptonl
Record of Decision - Hercules 009 Landfill, GA
Second Remedial Action - Final
Contaminated Media: soil, sludge, gw, sw
Key Contaminants: VOCs (benzene, TCE, toluene, xylenes), other organics (dioxin,
pesticides), metals (arsenic, chromi urn, lead)
b. Identifiers/Open-Ended Terms
c. COSATI Field/Group
18. Availability Statement 19. Security Class (this Report) 21. No. of Pages
None 72
20. Security Class (this Page) 22. Price
I None
(See ANSI.Z39.18)
SH InstructiDns on Rllv-
OPTIONAL FORM 272 (4.77)
(Farmerly NTJS.35)
Department of Commerce
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EPA/ROD/R04-93/144
Hercules 009 Landfill, GA
Second Remedial Action - Final
Abstract (Continued)
1982, EPA banned the use of toxaphene and site operations ceased. A 1991 ROD addressed an
inter~ action for ground water by extending the existing municipal water lines, as OU2.
This ROD provides a final remedy for the site and addresses contaminated soil, debris,
sludge, ground water, and surface water, as OUI. The primary contaminants of concern
affecting the soil, sludge, ground water, and surface water are VOCs, including benzene,
TCE, toluene, and xylenes; other organics, including dioxin and pesticides; and metals,
including arsenic, chromium, and lead.
The selected remedial action for this site includes conducting a field-scale treatability
study; excavating and transporting the subsurface soil, sludge, and related material in
the staging area with levels exceeding 76 mg/kg of toxaphene,' and the surface soil in the
staging area with levels exceeding 0.25 mg/kg of toxaphene to the landfill area; treating
the consolidated surface soil, subsurface soil, and sludge using in-situ stabilization as
an innovative application to treat organics; covering treated soil and sludge using a clay
multi-media cover; backfilling excavated areas with two feet of c~ean native fill;
providing for a contingency remedy to treat the soil and sludge by dewatering the soil and
sludge, onsite ex-situ chemical extraction, with onsite disposal of the treated material,
based on the results of a treatability study; monitoring ground water, surface water,
sed~ent, and air; providing for a contingency remedy to extract and treat contaminated
ground water onsite using granular activated carbon or another treatment, followed by
onsite or offsi~e discharge to a POTW, and offsite disposal of the spent granular
activated carbon, if toxaphene or other chemicals are shown to be migrating offsite or
from their current positions, or contaminants of concern begin to increase over 50% of
their current value, or it does not seem feasible that the ground-water will naturally
attenuate over t~e; operating and maintaining the cover for a min~um of 30 years and
possibly abandoning onsite private wells; and implementing institutional controls,
including deed restrictions. - The estimated present worth cost for this remedial action i~
$9;900,000, which includes an estimated annual O&M cost of $104,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil excavation goals are based on attaining the baseline risk equal to
or less than lx10-6 for toxaphene, and include surface soil 0.25 mg/kg and subsurface soil
76 mg/kg. Chemical-specific surface soil goals are based on the risk assessment of 1x10-6
for future land'use, and include alpha-BHC 0.044 mg/kg; arsenic 5 mg/kg; acetone 360
mg/kg; benzene 10 mg/kg; beryllium 0.15 mg/kg; bis (2-ethylhexyl) phthalate 20 mg/kg;
cadmium 41 mg/kg; carbon tetrachloride 2.1 mg/kg; chlorobenzene 720 mg/kg; chloroform 45
mg/kg; chromium (III) 56 mg/kg; copper 3,300 mg/kg; dioxin/furans (TEF) 0.001 mg/kg;
Endosulfan II 1.8 mg/kg; ethylbenzene 3,600 mg/kg; lead 500 mg/kg; manganese 4,900 mg/kg;
mercury 26 mg/kg; methylene chloride 37 mg/kg; nickel 310 mg/kg; toluene 7,200 mg/kg; TCE
25 mg/kg; toxaphene 0.25 mg/kg; vanadium 600 mg/kg; xylenes 70,000 mg/kg; and zinc 17,000
mg/kg. Chemical-specific subsurface soil goals are based on the risk assessment of 1x10-6
for future land use, and include acetone 1 mg/kg; alpha-BHC 0.01 mg/kg; arsenic 3,400
mg/kg; benzene 0.06 mg/kg; beryllium 61 mg/kg; bis (2-Ethylhexyl) phthalate 46 mg/kg;
cadmium 11,000 mg/kg; carbon tetrachloride 0.07 mg/kg; chlorobenzene 1.7 mg/kg; chloroform
0.4 mg/kg; chromium (III) 1,000,000 mg/kg; copper 420,000 mg/kg; dioxin/furans (TEF) 0.14
mg/kg; Endosulfan II 0.29 mg/kg; ethylbenzene 13 mg/kg; lead 500 mg/kg; manganese.
1,000,000 mg/kg; mercury 3,400 mg/kg; methylene chloride 0.03 mg/kg; nickel 220,000 mg/kg;
TCE 0.08 mg/kg; toluene 30 mg/kg; toxaphene 76 mg/kg; vanadium 79,000 mg/kg; xylenes 80
mg/kg; and zinc 1,000,000 mg/kg. Chemical-specific ground water goals for natural
attenuation are based on SDWA MCLs, and include benzene 0.005 mg/l; cadmium 0.005 mg/l;
chromium 0.1 mg/l; manganese 0.05 mg/l; nickel 0.1 mg/l; toluene 1 mg/l; toxaphene 0.003
mg/l; and xylenes 10 mg/l.
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RECORD OF DECISION
SUMMARY OF REMEDIAL AL TERNATIVE SELECTION
HERCULES 009 LANDFILL SITE
OPERABLE UN" ONE
BRUNSWICK, GL YNN COUNTY, GEORGIA
PREPARED BY
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
ATLANTA, GEORGIA
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DECLARATION
of the
RECORD OF DECISION
OPERABLE UNIT ONE
SITE NAME AND LOCATION
Hercules 009 Landfill Site
Brunswick, Glynn County, Georgia
STATEMENT OF BASIS AND PURPOSE
-
This decision document (Record of Decision), presents the selected
remedial action for Operable Unit One for the Hercules 009 Landfill
Site, Brunswick, Georgia, developed in accordance with the
Comprehensive Environmental Response, Compensation and Liability Act
o~ 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA) 42 U.S.C. Section 9601 ~ ~., and
to the extent practicable, the National Contingency Plan (NCP) 40 CFR
Part 300.
This decision is based on the administrative record for the Hercules
009 Landfill site ("the Site").
The State of Georgia has concurred with the selected-remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the
Hercules site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare or the environment.
DESCRIPTION OF SELECTED REMEDY
This operable unit is one of two for this Site. This alternative
calls for the design and implementation of response measures which
will protect human health and the environment. Operable unit one,
which is enumerated by this Record of Decision, addresses the source
areas, surface water, and groundwater at the Site. Operable unit.two
was enumerated in an Interim Action ROD that was signed by EPA on June
27, 1991. Operable unit two addressed the off-site threat of future
groundwater contamination by extending the existing municipal water
lines in the City of Brunswick, Georgia to residents that live
adjacent to this Site.
The major components of the selected remedy for operable unit one
include:
.
Conducting a field-scale treatability study and implementation of
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in-situ stabilization of subsurface soils and consolidated surface
soils. ~his remedy is an innovative application of this
technology since EPA has minimal information on stabilization of
manufactured pesticides;
.
Implementation of an ex-situ chemical extraction technology on the
soils and sludges at the Site (with onsite disposal of the treated
material) in the event the treatability study concerning the
stabilization of Site soils and sludges fails to met the reqtiired
standards and therefore will not be effective if implemented;
.
Construction of a cover over the treated soils to reduce rainwater
infiltration. and direct contact with the treated soil. In .
addition, areas excavated for consolidation of surface soil would
be graded and covered with two feet of clean, compacted, native
fill; .
.
Long-term monitoring of groundwater, as well a~ surface water and
sediment in the onsite pond and the adjacent drainage. ditch, with
the contingency implementation of a pump and treat system in case
any of the following occurs: toxaphene begins to migrate off the
Hercules property; if the other contaminants of concern are shown
to be ~igrating from their current positions; if any levels of the
contaminants of concern begin to increase over fifty percent of
their current value; or in case it becomes apparent that onsite
levels of contaminants in the groundwater will 'Rot naturally
attenuate below MCLs over tim~;
Operation and maintenance of the cover for a minimum of thirty
years; and
.
.
Institutional controls for land use and groundwater use
restrictions.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment,
complies with federal and state requirements tnat are legally
applicable or relevant and appropriate to the remedial action, and is
cost-effective. This remedy satisfies the preference for treatment
that reduces toxicity, mobility, or volume as a principal element.
Finally, it is determined that this remedy utilizes a permanent
solution and alternative treatment technology to the maximum extent
practicable.
Because this remedy will result in hazardous substances remaining
'onsite above health-based levels, a review will be conducted within
five years after commencement of the remedial action to ensure that
the remedy continues to provide adequate protection of human health
and the environment.
~&f'r1~
PATRICK M. TOBIN, ACTING REGIONAL ADMINISTRATOR
s-2F-7:s
DATE
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1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
TABLE OF CONTENTS
Site Location and Description........... ......................1
Site History and Enforcement Activities...... .................1
Highlights of Community Participation... .... ..................4
Scope and Role of Operable Units. . . . . . . . . . . . . . . . . . . . .. . . . . . . . .5
Summary of Site Characteristics........ ..... ..................5
5.1 Geology/Soils........................... '-' . . . . . . . . . . . . . . . .5
5 . 2 Hydro 1 ogy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.3 Surface Water and Sediments....... . . . . . . . . . . . . . . . . .. . . . . .8
5.4 Air Monitoring.. . . . . . . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . .9
Summary of Si te Risk..... . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .9
6.1 Contaminants of Concern..... ................. ......... ...9
6.2 Exposure Assessment..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
6.3 Toxicity Assessment. . . . . . . . . . . . . . . . . . . . . .-. . . . . . . . . . . . . . .15
6.4 Risk Characterization...................................15
6.5 Environmental Risk..................................... .16
6.6 . Cleanup Goals................... . . . . . . . . . . . . . . . . . . . . . . . .18
Description of Alternatives......... .... ..... ................20
7.1 Alternative No.1 - No-Action.......................... ..24
7~2 Alternative No.2 - Pump and Treat.......................24
7.3. Alternative No.3 - RCRA Cap..............:-:.............25
7.4 Alternative No.4 - In-Situ Stabilization.............. ..26
7.5 Alternative No.5 - Chemical Extraction..................28
Summary of the Comparative Analysis of Alternatives........ ..29
8.1 Overall Protection of Human Health and the Environment...33
8.2 Compliance With ARARS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
8.3 Long-Term Effectiveness and Permanence... ................40
8.4 Reduction of Toxicity, Mobility or Volume By Treatment...43
8.5. Short-Term Effectiveness. .......... ......................43
8.6 Implementability......................................... 45
8.7 Cost..................................... .. . . . . . . . . . . . . . . .48
8.8 State Acceptance........................................ .49
8 . 9 Community Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
9.0
Summary of Selected Remedy.. ........... ..... ................50
10.0 Statutory Determination. . . . . . . . . . . . . . . . . . . . . . .-. . . . . . . . . . . . . .58
10.1 Protective of Human Health and the Environment...........59
10 . 2 At t a i nmen t 0 f ARARs...................................... 5 9
10.3 Cost Effectiveness....................................... 61
10.4 Utilization of Permanent Solutions.. ..... ................61
10.5 Preference for Treatment as a Principal Element......... .61
11.0
Documentation of Significant Changes... ...... .... ...........62
Appendix A - Respo;-,si veness Summary............................... 63
Appendix B - Concurrence Letter... ........... .................... .97
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Table 6-1
Table 6-2
Table 6-3
Table 6-4
Table 6-5
Table 8-1
Table. 8-2
Table 8-3
Table 8-4
Table 8-5
LIST OF TABLES
Chemicals of Concern - Sludge and Soil...................10
Chemicals of Concern - Groundwater.......................12
Summary of Cumulative Potential Cancer Risk and Non-
Carcinogenic Hazard Indices.. . . . . . . . . . . . . . . . . . . . . . . . . . .17
Remedial Action Target Concentrations.~..................22
Estimated Volumes of Affected Materials...~..............23
Comparative Analysis of Alternatives...:.................31
Potential Location-Specific ARARs......................~.36
Potential Action-Specific ARARs for Selected Remedy......37
Potential Action-Specific ARARs for Contingent Remedies..38
Comparison of Costs...................................... 49
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Figure 1-1
Figure 1-2
Figure 5-1
Figure 6-1
LIST OF FIGURES
Area Map for" Brunswick, Georgia..........................2
Site Map for the Hercules 009 Landfill Site..............3
Cross-Section of a Typical Landfill Cell at the Site.....7
Map of Monitoring Well Locations......~.................21
Figure 9-1- Map Showing Locations of Major Areas to be Stabilized...54
-].].].-
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Decision Summary
Record of Decision
Operable Unit One
HerCules 009 Landfill Site
Brunswick, Georgia
1.0 SITE LOCATION AND DESCRIPTION
The Site is located in the eastern portion of Glynn-County, Georgia,
approximately two miles south of Interstate 95 and one-half mile north
of the City of Brunswick as shown on Figure 1-1. Figure 1-2 is a map
of the Site. The Site is a .16.5 acre property that is bordered by
Georgia State Highway 25 (Spur 25) on the west; an automobile
dealership on the north; a juvenile slash pine forest on the east; and
several homes, a church, a school, and a strip shopping center to the
south/southeast of the property. A shopping mall, built in 1985, a
bank, and a restaurant are located approximately 1,000 feet north of
the landfill~ The property is fenced and has only one entrance
through a locked gate.
Seven acres on the north end'of the property were operated as an
industrial landfill by Hercules between 1976 and 1980 under'a permit
by the Georgia Environment'al Protection Division (GaEPD). The permit
allowed for the disposal of wastewater sludge generated from the
production of toxaphene at the Hercules Brunswick Plant. Six disposal
cells were constructed at the northern end of the property to receive
sludge for disposal. During its years of operation, the 009 Landfill
was monitored by the GaEPD.
2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIES
Hercules began manufacturing toxaphene, an agricultural pesticide, in
1948 and continued production through 1980. Toxaphene received
widespread use in the southeastern United States to control boll
weevils as well as mites and ticks on cattle, until EPA banned its use
in 1982. The Site had been used by the State as a borrow pit for soil
during the construction of Spur 25. Hercules was issued a permit in
1975 by the GaEPD to use seven acres at the northern end of the
property as a landfill to dispose of wastewater sludge generated
during the manufacturing processes.
The 009 Landfill was constructed at the northern end of the property
as six cells, each approximately 100 to 200 feet wide (north-south
direction) and 400 feet long (west-east direction). The thickness of
the toxaphene sludge in the cells was reported to be six to seven
feet. Individual cells were reported to be lined with a
1
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..."""
\ ""
\
\
APPAOXIIMTl; SCALE:
,. - '
Figure 1-1
Area Map for Brunswick, Georgia
soil/bentonite clay mixture across the bottom of the cell and along
the bermed walls.
The sludge deposited in the 009 Landfill consisted of very fine
calcareous particulate, diatomaceous earths and finely crushed
limestone material. Toxaphene adsorbed to this material during
neutralization of by-product hydrochloric acid. Reportedly, the
wastewater treatment sludge consisted of about one percent toxaphene
by weight and 50 percent solids by weight. The sludge was transported
to the landfill in bulk by truck. Trucks hauling material to the Site
reportedly entered the landfill through two entrances, one from
Benedict Road (south side), the other located along Spur 25 (west
side). Typically. the sludge was placed directly into the landfill.
However, sludge was occasionally staged near the southeastern corner
2
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-.
Figure 1-2
Site Map for the Hercules 009
Landfill Site
of the 009 Landfill prior to placement.
In addition to the sludge, the 009 Landfill was also used for disposal
of empty toxaphene product drums, and toxaphene contaminated
glassware, rubble, and trash. Disposal of this material was primarily
limited to Cell 1. Hercules estimated that approximately 33,000 cubic
yards of sludge had been disposed of in the landfill. The cells were
covered with a 24 to 30 inches of "stump dirt" mixed with boiler ash.
The term "stump dirt" refers to soil that was entrained on pine stumps
purchased by the Hercules Brunswick Plant for the extraction of resins
and essential oils.
3
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All cells in the landfill were closed prior to 1983 in accordance with
existing GaEPD Solid Waste Management Regulations. The final contour
of the top of the landfill has a slope of approximately one percent .to
prevent pooling and to minimize infiltration of precipitation. The
sides of the unit have a slope of about ten percent. To control
erosion, the earthen cover was seeded with grasses that have proven to
grow well in the Brunswick area. .
A drainage ditch is located adjacent to the landfill at the eastern
edge. To control surface runoff from the surrounding area, Glynn
County periodically excavates the sediments from this ditch to ensure
adequate drainage capacity. Prior to 1988, sediments from the ditch
were stockpiled on the eastern bank of the ditch, but in early 1988,
these sediments were removed.
During its operation, the landfill was inspected by GaEPD. In March
1980, GaEPD collected soil and water samples from drainage ditches
around the Site. The samples contained toxaphene. As a result, GaEPD
canceled Hercules' permit and the 009 Landfill was closed under a plan
approved by GaEPD.
EPA calculated a Hazard Ranking Score for the closed landfill. In
1984, the landfill was placed on the National Priority List (NPL). As
of July 1, 1991, the Hercules 009 Landfill Site ranked 152 out of 1072
on the NPL (excluding federal facilities). GaEPD began negotiations
with Hercules to perform an RI/FS and initiated Site investigation
activities under State Superfund authority, then withdrew as lead
agency in 1987. EPA assumed primary cont~ol of the Site investigation
and related activities at the end of 1987. Hercules and EPA entered
into an Administrative Order on Consent in July 1988. The Consent
Order required Hercules to perform a Remedial Investigation
/Feasibility Study (RI/FS) of the Site.
3.0
HIGHLIGHTS OF COMMUNITY PARTICIPATION
The main branch of the Brunswick-Glynn Regional Library at 208
Gloucester Street in Brunswick, Georgia was chosen as the local
information repository for the Site. A public comment period for the
proposed plan for operable unit #2 (concerning extension of the
municipal water lines) was held from May 13, 1991 to June 12, 1991.
with a public meeting being held on May 15, 1991.
The public comment period on the proposed plan preceding this ROD
(operable unit #1) was held August 27, 1992 through October 27, 1992.
A public meeting was held on Thursday, September 10, 1992 where
representatives from EPA answered questions from approximately 150
people regarding the Site and the proposed plan under consideration.
The administrative record was available to the public at both the
information repository maintained at the Brunswick-Glynn Regional
Library and at the EPA Region IV Library at 345 Courtland Street in
Atlanta, Georgia. The notice of availability of these documents was
4
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published in the Brunswick News-Herald on August 24, and September 4,
1992. EPA received numerous oral and written comments during. the
comment period. Responses to the significant comments received are
included in the Responsiveness Summary, which is part of this ROD and
designated Appendix A.
This decision document presents the selected remedial action for
operable unit one of the Hercules site, chosen in accordance with
CERCLA, as amended by SARA and to the. extent practicable, the NCP.
The decision for this Site is based on the administrative record.
requirements under Section 117 of CERCLA/SARA for public and state
participation have been met for this operable unit.
The
4.0
SCOPE AND ROLE OF OPERABLE UNITS
EPA has organized the work at this Superfund Site into two operable
units (OUs). These units are:
.
OU one:
The source area at the Site, including the landfilled
sludge, the soils in the sludge-staging area, and the
Benedict Road/Nix Lane area. Contamination in the
groundwater, surface water, sediment, and soils are
addressed in OU #1. Proper abandonment of the private
wells replaced during OU #2 is included in OU #1 if the
owners will allow abandonment.
.
OU two:
The extension of municipal water lines to residents
adjacent to the Site was specified in OU #2 to address.
the threat of a groundwater plume that could affect
residential drinking wells downgradient of the Site.
OU #1 addresses both the source pf contamination in the soils as well
as the groundwater contamination underneath the Site. The purpose of
this operable unit is to monitor groundwater restoration, treat the
source areas at the Site, prevent current or future exposure to the
contaminated soils and groundwater, and reduce contaminant migration.
OU #1 will be consistent with the actions taken during OU #2, to the
extent practicable. The Record of Decision (ROD) governing OU #2
dated June 27, 1991 erroneously was titled OU #1. However, the ROD
dated June 27, 1991 documents the remedial action selection for OU #2.
This ROD documents the remedial action selection for OU #1.
5.0
SUMMARY OF SITE CHARACTERISTICS
5.1
GEOLOGY/SOILS
The results of the RI led to the following findings and conclusions:
.
The Site lies in the Atlantic Coastal Plain province of Georgia.
Surface sediments are described as relatively thin layers of
sands, gravels I and clays of Pleistocene age. These sedi~,lents I
generally less than 150 feet thick, represent the surficial layer.
5
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Beneath the surficial layer are Miocene sediments which are
represented by the Hawthorn formation. The Hawthorne contains
several clay units and is a confining zone between the surficial
water-bearing unit and the deeper Floridan aquifer. The Floridan
aquifer, at an approximate depth of 500 feet, is separated from
the surficial water-bearing unit by approximately 400 feet of the
Miocene sediments. The Floridan aquifer is the primary aquifer in
the area for large irrigation and municipal supplies, while
shallower wells are used for small domestic supplies.
.
Soils at the Site consist of coarse to clayey sands, sandy silts,
and sandy to silty clays. The soils can be grouped into three
distinct hydrogeologic components. From land surface to depths of
25 to 45 feet below land surface isa zone composed of silty sands
and sandy silts. Underlying this zone is a clayey sand and sandy
clay interval ranging in thickness from 10 to 25 feet. The clayey
interval may possibly act as a semi-confining unit within the
surficial layer dividing the silts and sands into shallow and deep
zones beneath the Site; however, the continuity of this. unit to
the west side of the landfill is not completely defined due to
limited drilling on the upgradient (west) side of the landfill.
The material that imrnediatelyunderlies the clayey zone,
representing the third unit, is composed of sands and silty sand
to approximately 85 feet below land surface, where a change to a
coarse sand containing gravel is noted.
.
Site-specific permeability values ranged from 4x10-s centimeters
per second to 9x10-s centimeters per second and correspond to the
shallow zone of the surficial water-bearing unit.
.
. Toxaphene concentrations in the soils surrounding the landfilled
sludge ranged from below the detection limit to 4,900 ppm.
Concentrations of toxaphene were generally highest in the vicinity
of the landfill cells and decreased with distance from the cells.
An exception was an area near the Benedict Road/Nix Lane entrance
to the: Site. Toxaphene concentrations of 26 ppm to 92 ppm in this
area may be the result of sludge transportation to the landfill.
Toxaphene was detected in landfilled sludge samples at
concentrations ranging from 850 to 15,000 ppm. The average sludge
concentration of toxaphene is 6,000 ppm. .
.
.
Acetone, carbon tetrachloride, chlorobenzene, chloroform, and
xylenes were detected in the landfilled sludge samples, but were
not consistently present. No volatile organic constituents (VOCs)
were detected in samples from cells 3, 4, and 6. One or more VOCs
was detected in samples from cells 1, 2, and 5.
.
Arsenic, chromium, copper, lead, manganese, nickel, vanadium, and
zinc were detected in sludge samples. Of these metals, only
copper and lead exceeded typical background concentration ranges.
.
6
Dioxins and furans were detected in all of the sludge samples.
6
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When evaluated based on the Toxicity Equivalence Factor (TEF), by
which the concentrations of all isomers are adjusted by their
toxicity relative to the 2,3,7,8-TCDD isomer, the concentrations
ranged from 3.2 X 10-5 to 3.9 X 10-4 ppm. These concentrations
exceeded background concentrations, but were less than the action
level of 1 x 10-3 ppm.
5.2
Hvdroqeoloqy
Groundwater in the shallow zone of the surficial water-bearing
unit flows toward the east at a seepage veloci~y of 60 to 90 feet
per year. Groundwater in the lower zone flows toward the
southeast at, a seepage velocity of 45 to 65 feet per year.
.
.
Surface elevations at the Site range from 13 to 26 feet mean sea
level (MSL). Water table elevations at the site range from 14 to
17 feet MSL.
.
Interpretation of data obtained during the drilling of boreholes
into the landfill and from piezometer water levels suggest the
following: water is perched above the sludge; saturated sludge
exists within the landfill cells; and there is an unsaturated zone
beneatq the sludge at least part of the year in portions of the
landfill. Figure 5-1 illustrates a typical landfill cell cross-
section. The saturated conditions within the sludge are due to
the absence of a clay cap on the landfill, the ,low permeability
(7x10-7 em/see) of the sludge material, and the bentonite layer
beneath the sludge.
WEST
EAST
I WATER TAILE
't PEACHED WATER
Figure 5-1
Cross-Section of a Typical Landfill Cell at the Site
7
-------
.
Private water supply wells located near the Site have been sampled
annually by Hercules since 1985. Toxaphene has not been detected
above instrumentation quantification limits in the private wells.
.
Groundwater elevations ac the Site exhibit minor cyclical
fluctuations that may be attributable to the tidal cycle.
,However, tidal influences are insufficient to affect basic
groundwater flow patterns.
.
Toxaphene has been detected in four monitoring wells all located
at the-southeastern corner of the landfill at cQncentrations
ranging from 0.0056 ppm to 0.076 ppm. During the latest round of
. sampling, only one ~ell indicated toxaphene contamination,
measured at 0.069 ppm.
Both nickel and benzene have been detected a~ove MCLs in
groundwater samples collected adjacent to the landfill.
.
5.3
Surface Water
.
Surface drainage occurs by overland flow at the Site. The flow at
the Site is divided by the crest of the landfill with both
westward flow toward Highway Spur 25 and eastward flow toward the
drainage ditch located immediately east of the Site. The drainage
along Spur 25 flows through a 36-inch culvert which connects to
the drainage ditch on 'the eastern side of the Site. , This culvert
transverses the Site immediately south of the landfill cells.
Surface drainage from the Glynn Place Mall (approximately 1000
feet north of the Site) enters the east drainage ditch upstream of
the Site. The pond at the southern end of the Site receives
runoff only from the immediate area surrounding the pond, and has
no permanent surface inflow or outflow. This onsite pond is
believed to have been formed during the construction of Spur 25 as
a borrow pit.
.
.
The water table is generally close to the bottom of the drainage
ditch, and groundwater flow from underneath the landfill may
seasonally discharge into the drainage ditch. The water table
configuration is, however, based on a single set of water table
elevations from a single date. Nevertheless, this data indicates
that the water table would provide only minor discharge to the
drainage ditch located immediately east of the Site.
.
Surface water and sediment samples were collected in the onsite
pond and in the off-site drainage ditch. Samples in the drainage,
ditch were collected both alongside the Site and over a mile away
from the Site in the estuary. Toxaphene was not detected in any
surface water samples. However, toxaphene'was detected at a
maximum of 0.86 ppm in two sediment samples adjacent to the Site.
8
-------
.
The biological studies conducted indicate that the Site has not
adversely affected the tested animal communities within the
drainage ditch or the estuary.
5.4
Air Monitorinq
.
An onsite air quality' monitoring program was conducted using four
high volume air samplers equipped with polyurethane foam absorbent
cartridges located on each side of the landfi~l cell area.
Toxaphene concentrations were below the detection limit of 50
mg/~.
6.0
SUMMARY OF SITE RISKS
CERCLA directs EPA to conduct a baseline risk assessment to determine
whether a Superfund Site poses a current or potential threat to human
health and the environment in the absence of any remedial action. The
baseline risk assessment provides the basis for determining whether or
not remedial action is necessary and the justification for performing
remedial action.
6.1
CONTAMINANTS OF CONCERN
The chemicals measured in the various environmental media during the
RI were evaluated for inclusion as chemicals of potential concern in
the risk assessment by application of screening criteria. The
criteria which resulted in elimination of chemicals included: Site
contaminant concentrations below background concentrations;
measurements below quantification limits; a combination of low
toxicity and low concentration or low persistence and low
concentration and low frequency of detection.
Tables 6-1 and 6-2 summarize the maximum detected concentrations of
the chemicals of concern in the subsurface soil, surface soil, sludge,
and groundwater at the Site. No waste constituents were detected
during Site air monitoring.
6.2
EXPOSURE ASSESSMENT
Whether a chemical is actually a concern to human health and the
environment depends upon the likelihood of exposure, i.e. whether the
exposure pathway is currently complete or could be complete in the
future. A complete exposure pathway {a sequence of events leading to
contact with a chemical} is defined by the following four elements:
.
A source and mechanism of release from the source,
.
A transport medium {e.g., surface water, air} and mechanisms
of migration through the medium,
.
The presence or potential presence of a receptor at the
exposure point, and
9
-------
CONSTm1ENT
~
Surface Soil
Subsurface Soil
Sludp
Ber,Wum
Surface Soil
Subawface SoU
Sludp
c.dmbim
Surface Soil
Subaurface Soil
Sludp
Chromium
Surface Soil
Subaurface Soil
Sludge
Copper
Surface Soil
Subaurface Soil
Sludge
Le8d
Surface Soil
Subsurface Soil
Sludp
-...--
Surface Soil
Subsurface Soil
Sludge
-...,.,.
Surface Soil
Subsurface Soil
Sludge
Nick-
Surface Soil
Subsurface Soil
Sludge
V.D8d1am
Surface Soil
Subsurface Soil
Sludge
ZiDe
Surface Soil
Subsurface Soil
Sludge
Aee&o.e
Surface Soil
Subaurface Soil
Sludge
bi8(S-Etbylhnyl)pbtbalate
Sllrface Soil
Subaurface Soil
Sludge
S--
surface Soil
Subsurface Soil
Sludge
Carbo. Tetrachloride
Sllrface Soil
Subsurface Soil
Sludge
TABLE 8-1
CBEMICALS OF CONCERN. SLUDGE AND SOIL
I-=I~~
1
2
6
o
1
o
o
1
o
8
28
6
7
18
6
36
10
6
20
10
6
1
6
o
1
2
4
11
5
1
8
22
6
3
14
1
o
4
o
1
o
o
o
o
2
10
10
37
6
10
S7
6
10
37
6
11
37
6
10
37
6
37
10
6
37
10
6
10
37
6
10
37
6
S7
10
6
10
37
6
10
37
6
4
8
6
10
37
6
10
37
6
I "::T: I
ND . 1.0
ND . 0.55
ND-7.0
-
ND
ND - 0.28
ND
1m
ND-3.6
ND
ND-8.2
liD - 30.9
6. 3 . 12.1
ND - 41.6
ND - 73.9
22.8 - 63.6
ND . 238
1.6 - 228
20.6 - 71.8
ND --60.9
6.9. 1,740
79.5 - 657
ND - 0.10
ND - 0.26
ND
ND. 3.9
ND-24
ND - 46.7
ND - 21.6
ND - 33.3
ND - 78.7
ND - 89.1
ND - 273
40.4 - 221
ND - 0.11
ND- 0.43
ND-U
ND
ND - 0.63
ND
ND - 0.011
ND
ND
ND
ND
ND-4.0
-------
Cot.stitueDt 0.: - .--
N1DIIbw of u.-tiou H1mIb8r of CONCENTBATIO
........ N
CONSTmJENT RANGE (ppm)
Chl~
&ufaao SOU 1 10 ND.O.oH
Suhaurface SOU 1 37 ND . 0.009
Sludge 1 6 ND-1.6
Chloral.....
Surface SoU 0 10 ND
Subaurface SoU 0 37 ND
Sludge 3 6 ND-4.0
-
~
Surface SoU 0 10 ND
Subaw'face SOU 3 37 ND - 0.46
Sludge 0 6 1m
Me&b)1- CbJorid.
Surface SOU 1 10 ND - 0.013
Suhaurface SOU 7 37 ND - 0.026
Sludge 0 6 ND
To-- -
Surface SOU 1 10 ND - 0.025
Sub8urface SoU 2 37 ND - 0.025
Sludge 0 6 ND
TrimJo......o.",t_.
Surface SOU 1 10 ND - 0.01
Suhaurface sOu 0 37 ND
Sludge 0 6 ND
XyleD8
Surface SOU 1 10 ND - 0.009
Suhaurface SOU 3 37 ND-U
Sludge 1 6 NJj:U
EDd-.JlaD n
Surface Soil 1 10 ND - 0.022
Suhaurface SoU 0 37 ND
Sludge 0 6 ND
TosapbeDe
Surface Soil 14 18 ND - 92.0
Subaurface SOU 32 62 ND - 4,900
Sludge 6 6 860 - 15.000
DiodDlFurau (TEF)
Surface SOU 9 9 3.1xlo-T - 3.6xlo-"
Subaurface SOU 4 7 ND - 7.5xlo-"
Sludge 6 6 7s1o-" - S.9xlo-"
ND - Not Deleded
11
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TABLE 6-1
CHEMICALS OF CONCERN - Grmmdwater
Anenic
Beryllium
f^pi^mjiifti
Chromium
Copper
Lead
Manganese
Nickel
Vanadium
Zinc
Acetone
Benzene
Ethylbenzene
Toluene
Xylenea
Toxaphene
DioxuHfunn*
Constituent Occurrence
NUIUDW
of Detection
1
1
2
5
2
5
21
4
1
4
3
1
1
1
2
3
7
Number of Svnple*
32
32
32
32
32
32
32
32
32
32
26
31
31
31
31
40
9
Concentration Bu(«
(Pin)
ND- 0.003
ND- 0.002
ND - 0.0055
ND- 0.121
ND- 0.067
ND - 0.106
ND-2.78
ND - 0.186
ND- 0.118 ~
ND- 0.382
ND - 0.870
ND - 1.10
ND - 0.015
ND - 0.062
ND - 0.035
ND - 0.10
ND - 4.1 x 10*
MCL
(ppm)
0.06
0.004
0.005
0.1
NA'
NA"
0.05'
0.1
NA
5'
NA
0.005
0.7
1
10
0.003
3x10-"
ND -
NA -
Not Detected
Not Available
MO. fc femdiot upon Ox tnugunt udulv>«i onwnt idleB Iwd to 0.016 ppn
• A route of exposure (ingestion, inhalation, dermal
absorption).
If all four elements are present, the pathway is considered complete.
The four major constituent release and transport mechanisms
potentially associated with the Site are as follows:
• The infiltration of precipitation through the wastes and
affected soils and the percolation of the resulting leachate
into subsurface soils and groundwater, followed by
groundwater transport.
• Release of affected surface soil through surface water
run-off. Dissolved constituents and constituents adsorbed
to soil particles could be conveyed to the drainage ditch on
the eastern edge of the Site that runs from the Site, past
an elementary school, and through a residential area prior
to discharging into the estuary approximately one mile from
the Site.
12
-------
.
Release of affected surface soil through wind erosion.
Surface soils could be suspended in air and transported from
their source by the wind.
.
Release of volatile compounds from soils and waste to the
atmosphere. These ~onstituents could be transported and
dispersed by the wind.
Because the thick vegetation and ground cover present at the Site will
impede volatilization and wind erosion, exposure to constituents in
air, either as vapor or adsorbed to dust, is not considered
significant- at the Site under current land use condi~ions. The
presence of vegetation also minimizes direct contact with surface
soils by Site visitors.
An evalua~ion was undertaken of all potential exposure pathways which
could connect chemical sources at the Site with p~tential receptors.
All possible pathways were first hypothesized and evaluated for
co~pleteness using the above criteria. Four current potentially
complete exposure pathways and seven future exposure pathways remained
after screening. The current pathways represent exposure pathways
which coul~exist under current Site conditions while the future
pathways represent exposure pathways which could exist, in the future,
if .the current exposure conditions change. Exposure by each of these
pathways was mathematically modeled using generally'conservative
assumptions.
The current pathways are:
.
potential ingestion of surface soil by a trespasser;
.
potential absorption from surface soil by a trespasser;
.
potential adsorption from ditch sediment by a trespasser,
and
.
potential ingestion pf sediments and surface water by
terrestrial organisms.
The future pathways are:
.
dermal exposure to surface soil by potential onsite
residents;
.
ingestion of contaminated groundwater by potential onsite
residents;
.
ingestion of soil by potential onsite residents;
.
dermal exposure to ditch sediments by potential onsite
residents;
13
-------
.
inhalation of airborne dust by potential onsite residents;
.
ingestion of soil by an onsite worker; and
.
dermal contact with soil by an onsite worker.
The exposure point concentrations for each of the chemicals of concern
and the exposure assumptions for each pathway were used to estimate
the chronic daily intakes for the potentially complete pathways, with
the exception of the groundwater pathway. The chronic daily intakes
were then used in conjunction with cancer.potency factors and
noncarcinogenic reference doses to evaluate risk. .
The major assumptions about exposure frequency and duration that were
included in the exposure assessment were:
.
The most likely trespasser is a child, age 6-12.
.
The trespasser will spend equal time on all areas of the
Site.
.
The trespasser will visit the Site on a routine basis for
six years (age 6-12).
.
The average body weight of the trespasser over th.e six-year
period is 30.5 kg.
The trespasser will visit the Site 150 days per year (five
days per week over the summer and two days per week over the
school year) .
.
.
The resident will spend 24 hours per day, 365 days per year
onsite.
.
The resident child lives on the Site for the nine-year
period from ages 1 to 10. The resident adult lives on the
Site for 30 years.
.
The average weight of the child is 20.5 kg over the n1ne-
year period. The average weight of the adult is 70 kg.
.
The individual expected to have the highest exposure under a
commercial-use scenario is a grounds-keeper.
.
The grounds-keeper's weight is assumed to be 70 kg.
.
The grounds-keeper's exposure period is estimated to be 30
years.
.
The grounds-keeper's exposure frequency is anticipated to be
43 days per year (one day per week for a 43 week growing
season) .
14
-------
The baseline risk assessment considered three land use scenarios
without the added protection of any remedial action: current land
use, future commercial land use, and future residential land use.
Analysis of current land use examined exposure to a potential
adolescent trespasser at the Site. Hypothetical exposure was assumed
to occur by direct contact with surface soil and sediments. Analysis
of the risk associated with future commercial land use considered
potential exposure to a grounds-keeper working at the Site.
Hypothetical exposure was assumed to occur by direct contact with
surface soil. Analysis future residential land use considered
potential exposure to a child and an adult res~,ding at the Site.
Exposure wa~ assumed to occur by direct contact with surface soil,
inhalation of airborne dust, and use of groundwater.- The resident
child was also assumed to contact stream sediments.
6.3
TOXICITY ASSESSMENT
Toxicity values are used in conjunction with the results of the
exposure assessment to characterize Site risk. EPA has developed
critical toxicity values for carcinogens and noncarcinogens. Cancer
potency factors (CPFs) have been developed for estimating excess
lifetime cancer risks associated with exposure to potentially
carcinogenic chemicals. CPFs, which are expressed in units of
(mg/kg/day)-l, are multiplied by the estimated intake of a'potential
carcinogen, in mg/kg/day, to provide an upper-bound 'estimate of the
excess lifetime cancer risk associated with exposure at that intake
level. The term uupper boundu reflects the conservative estimate of
the risks calculated from the CPF. Use of this conservative approach
makes underestimation of the actual cancer risk highly unlikely.
Cancer potency 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.
Reference doses (RfDs) have been developed by EPA for indicating the
potential for adverse health effects from exposure to chemicals
exhibiting noncarcinogenic'effects. RfDs, which are expressed in
units of mg/kg/day, are estimates of lifetime daily exposure levels
for humans, including sensitive individuals. Estimated intakes of
chemicals from environmental media can be compared to the RfD. RfDs
are derived from human epidemiological studies or animal studies to
which uncertainty factors have been applied (e.g., to account for the
use of animal data to predict effects on humans). These uncertainty
factors help ensure that the RfDs will not underestimate the potential
for adverse noncarcinogenic effects to occur.
6.4
RISK CHARACTERIZATION
Human health risks are characterized for potentia} carcinogenic and
noncarcinogenic effects by combining exposure and toxicity
information. Excessive lifetime cancer risks are determined by
multiplying the estimated daily intake level with the cancer potency
15
-------
factor. These risks are probabilities that are generally expressed in
scientific notation (e.g., 1x10-6). An excess lifetime cancer risk of
1x10-6 indicates that, as a plausible upper boundary, an individual
has a one in'one million additional (above their normal risk) chance
of'developing cancer as a result of Site-related exposure to a
carcinogen over a 70-year lifetime under the assumed specific exposure
conditions at a site. .
EPA considers individual excess cancer risks in the range of 1x10-4 to
1x10-6 as protective; however the 1x10-6 risk level is generally used
as the point of departure for setting cleanup levels at Superfund
sites. The_point, of departure risk level of 1x10-6 expresses EPA's
preference for remedial actions that result in risks-at the more
protective end of the risk range. The health-based risk levels for au
#1 are shown in Table 6-3.
Potential concern for noncarcinogenic effects of a ~ingle contaminant
in a single medium is expressed as the hazard quotient (HQ) (or the
ratio of the estimated intake derived from the contaminant
concentration in a given medium to the contaminants's reference dose) .
A HQ which exceeds o~e (1)' indicates that the daily intake from a
scenario exceeds the chemical's reference dose. By adding the HQs for
all contaminants within a medium or across all media, to which a given
population may reasonably be exposed, the Hazard Index (HI) can be
generated. The HI provides a useful reference point-for gauging the
potential significance of multiple contaminant exposures within a
single medium or across media. An HI which exceeds unity indicates
that there may be a concern for potential health effects resulting
from the cumulative exposure to multiple contaminants within a single
medium or across media. The HIs for au #1 are shown in Table 6-3.
The risk assessment results indicated that the risks due to exposure
to toxaphene in surface soil exceeded the 1 x 10-4 risk level for each
land use scenario. Exposure to sediments did not result in risks
exceeding the 1 x 10-6 benchmark. The hazard index exceeded 1.0 and
the increased carcinogenic risk exceeded 1 x 10-4 for ingestion of
groundwater. .
6.5
ENVIRONMENTAL RISK
Biological assessments included vegetation surveys, an elutriate
bioassay, a macroinvertebrate study, and bioaccurnulation studies in
the ditch and in the estuary.
The vegetation surveys concluded that no adverse effects on vegetation
at the Site or in the drainage ditch were apparent. The elutriate
bioassay concluded that no significant differences in reproductive
responses among the freshwater sampling points were apparent. The
macroinverteprate study concluded that the ditch adjacent to the
16
-------
LAND USE EXPOSURE EXPOSURE CARCINOGENIC NONCARCINOGENIC
PATHWAY MEDIUM RISK HAZARD INDEX
CURRENT Ingestion Surface Soil 3.2x10-s 6. 3x10-3
Absorption Surface Soil 4 . 5x1 0 -4 9. 3x10-3
Absorption Sediments 1 . 4x1 0: 7 2. 3x10-3
Total 4. 8x10-4 1.8x10-2
- 2.0x10-s- 7 .6x10-4
FUTURE Ingestion Surface Soil
COMMERCIAL 1.1x10-4 4. 8x10-4
Absorption Surface Soil
Total 1.3x10-4 1.2x10-3
FUTURE Ingestion Surface Soil 1.lx10-3 1.3x10-1
RESIDENTIAL 1.9x10-3 2. 6x10-2
(CHILD) Absorption Surface Soil
Inhalation Surface Soil 3. 5xlO-6 2. 3x10-1
-
Absorption Sediments 5. 7xlO-7 6. Ox10-2
Ingestion Groundwater 8. 3xlO-4- - 5. 7x10+o
Absorption Groundwater 5. 3xlO-7 3. 9x10-3
Total 3. 8xlO-3 6.1x10+o
FUTURE Ingestion. Surface Soil 5.0xlO-4 1.9xlO-2
RESIDENTIAL Absorption Soil 2. Ox10-3 8.5x10-3
(ADULT) Surface
Inhalation Surface Soil 3.5xlO-6 6. 4x10-2
Ingestion Groundwater 7.7x10-7 1.7x10+o
Absorption Groundwater 1 . 2x1 0 -6 2.6x10-3
Total 3. 3x10-3 1.8x10+o
Table 6-3
Summary of Cumulative Potential Cancer Risks
and Non-Carcinogenic Hazard Indices
landfill is a stressed environment, but less so downstream of the
landfill than upstream. The ditch is a stressed environment because,
as the upper reach of a storm drainage system, it experiences low to
no flow with periodic high storm flows, and because it is periodically
dredged. Toxaphene was not detected in any test organisms during the
bioaccumula~ion studies. The overall conclusion of the biological
assessments was that the landfill had not adversely affected the
drainage ditch or the estuary.
Representatives from the U.S. Fish & wildlife Service observed a wood
stork at the pond located on the south end of the Site. The wood
stork, Mycteria americana, is a listed endangered species protected
under the Endangered Species Act of 1973. However, under current Site
17
-------
conditions, environmental receptors are not exposed.to excessive
increased carcinogenic risk. Hazard indexes for environmental
receptors are \.,ithin acceptable levels.
6.6
CLEANUP GOALS
The establishment of health-based cleanup goals serves as an impcrtant
means of guiding remedial activities. A health-based approach is
warranted when cleanup standards promulgated by state or federal
agencies are not available for contaminants in soil, as well as for
certain groundwater contaminants.. The approach to_developing health-
based goals is derived from the risk assessment process. The risk
assessment is essentially a process by which the magnitude of
potential cancer'risks and other health effects at a site can be
evaluated quantitatively. A cleanup goal is establlshed by back-
calculating a health protective contaminant concentration, given a
target cancer risk which is deemed acceptable and realistic. The
concept of the cleanup goal inherently incorporates the concept of
exposure reduction which allows remedial alternatives to be flexible.
Although the contaminants of concern are not the only contaminants at
the Site, they were chosen based on toxicity, mobility and frequency
of detection throughout the Site. It is anticipated that contaminants
at the Sit&which do not have cleanup levels presented in this ROD
will be reduced to acceptable levels when cleanup levels are met for
the 'most toxic and most mobile contaminants for which cleanup levels
have been established.
Actual or threatened releases of hazardous substances from this Site,
if not addressed by implementing the response action selected in this
ROD, may present an imminent and substantial endangerment to public
health, welfare,.- or the environment.
Groundwater
Cleanup goals for groundwater are not presented in Table 6-4 since
only single contaminants in separate sampling locations are above MCLs
at the Site (See Figure 6-1 for monitoring well locations). .
Currently, monitoring well N-6SR has indicated toxaphene contamination
at a level of 0.069 ppm (the MCL is 0.003 ppm), well N-5 and KV-5
indicate benzene at levels of 0.13 ppm and 0.011 ppm respectively (the
MCL for benzene is 0.005 ppm), and KV-3 indicates nickel
contamination at a level of 0.186 ppm (the MCL for nickel is 0.1 ppm).
The MCL shall be the performance standard for groundwater to meet.
In 1990, toxaphene was detected in monitoring wells N-6S, N-11, N-12,
and one deep well, N-6D. Detected toxaphene concentrations ranged'
from 0.0056 ppm at well N-12 to 0.76 pprn at well N-11. It was noted
at the time of analysis that the deep well, N-6D may contain toxaphene
as an artifact of well construction. To further investigate this, N-
6D was abandoned in 1991 and replacement well N-6DR was installed
immediately adjacent to the original location. During the sampling
conducted in 1991, toxaphene was only detected in N-6S at a
concentration of 0.01 ppm. During the round of sampling in November
1991, toxaphene was not detected in groundwater samples collected from
wells N-6DR, N-11, and N-12. Since the single confirmed analytical
18
-------
detection of toxaphene could be an artifact of construction of
monitoring well N-6S (which was installed at the same time as N-6D),
N-6S was abandoned and replacement well N-6SR was installed in March
1992. Toxaphene was detected at 0.069 ppm in the groundwater sample
collected in March 1992 from N-6SR. The absence of toxaphene in
surrounding monitoring wells indicates that there is no plume of
toxaphene within the groundwater.
Benzene was detected in a groundwater sample collected from N-5 at
levels of 0.13 ppm and.0.970 ppm. Further evalu~tfon of benzene in
the groundwater downgradient of monitoring well N-5 was performed by
the collect~on of. KVA samples KV-5 through KV-8. Benzene was detected
in KV-5 at a concentration of 0.011 ppm.
Nickel was detected in KV-3 at 0.186 ppm, which is greater than the
MCL of 0.1 ppm. However, samples obtained using the KVA sampling
procedure may possibly contain higher levels of suspended solids due
to the absence of a sand pack which is normally found with a
monitoring well. Suspended solids present in groundwater samples may
cause analytical results to reflect higher concentrations that those
actually present.
Based on the above, no active remediation is to be immediately
implemented for groundwater. However, if contamination in the
groundwater does not attenuate to below MCLs, the MC~s would be the
cleanup target. The MCLs for toxaphene, nickel, and benzene are
listed in Table 6-2.
Soils
Surface soil requiring remediation were determined using risk-based
action levels, which are summarized in Table 6-4. The action levels
were calculated by using baseline risk assessment exposure assumptions
for exposure of a future resident child to surface soil. Action
levels for non-carcinogenic constituents were calculated using an
allowable hazard index of 1.0. Action levels for carcinogenic
constituents were calculated using an allowable increased cancer risk
of 1 x 10-6. Surface soil remediation target concentratiqns for
toxaphene were exceeded in numerous surface soil sampling locations.
Subsurface soil volumes requiring remediation were determined by two
methods. Inorganic constituent (metals) target concentrations were
calculated by using baseline risk assessment exposure assumptions for
future commercial land use (i.e., limited exposure to the soil).
Action levels for non-carcinogenic constituents were calculated using
an allowable hazard index of 1.0. Action levels for carcinogenic
constituents were calculated using an allowable increased cancer risk
of 1 x 10-6. Organic constituent target concentrations were
calculated using the Summer's model (EPA, 1989) for constituents
leaching to groundwater. Drinking water standards were used for
allowable groundwater concentrations. Both surface soil and
subsurface soil cleanup goals are presented in Table 6-4.'
19
-------
The following criteria were developed to calculate the volume of
affected soil.
.
In those areas where the deepest soil interval sampled in a .
boring indicates constituent concentrations exceeding remedial
action target concentrations, the remedial action limit is
assumed to lie within a distance of two feet below that datum.
The rationale for this criterion is based on observations made at
several locations across the Site. .
.
The lower excavation limit has been drawn parallel to the bottom
of the wastes where practical. This has been done in a manner to
approximate a reasonable excavation plan.
Surface soil sampling results indicate that several areas of the Site
contain surface soil with toxaphene concentrations that exceed the
surface soil. target concentration of 0.25 ppm. Ap~~oximate boundaries
of the affected surface soil were estimated by evaluating the
constituent concentrations in surface soil samples and shallow samples
from soil borings. Figure 9-1 is a plan view of the Site showing the
area of affected surface soil. Volume calculations were based on
excavation to two feet. Volume calculations for surface soil
excavation and remediation resulted in an estimate of 13,500 cubic
yards.
Sludge exceeds the subsurface soil target concentrations for
toxaphene. Sludge volumes ,were calculated based on historical
information about the construction of the landfill and on data
generated from landfill borings. Hercules' records indicated that
approximately 33,000 cubic yards of material were disposed in the
landfill. The quantity is closely approximated by the volume
estimates based on field calculations. Table 6-5 presents a summary
of the volumes estimated for the sludge and soil.
7.0
DESCRIPTION OF ALTERNATIVES
OVERVI~
The assembled Site-specific alternatives represent a range of distinct
waste-management strategies addressing the human health and,
environmental concerns. Although the selected remedial alternative
will be further refined as necessary during the pred~sign phase, the
analysis presented below reflects the fundamental components of the
various alternatives considered feasible for this Site.
20
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TABLE 6-4
REMEDIAL ACTION TARGET CONCENTRATIONS
SURFACE SOIL SUBSURFACE SOIL 009 LANDFILL
REMEDIATION REMEDIATION MAXIMUM
TARGET TARGET OBSERVED SOIL
CONSTITUENT CONCENTRATION" CONCENTRATIO~ CONCENTRATION"
(ppm) (ppm) (ppm)
Arsenic 5 3,400 1.0
Beryllium 0.15 61 O.~
Cadmium 41 11 000 3.6
Chromium (III) 56 1,000,000- 30.9
Copper 3,300" 420,000e 73.9
Lead - 500t 500t 238
Maol!8Dese 4900 1 000 000 1740
Men:u1')' 26 3,400 0.26
Nickel 310 220,000 24
Vanadium 600 79.000 33.3
Zinc 17000 1 000 000 273
Acetone 360 1.0 0.43
bis(2-Ethylhexyl)Phthalate 20 46 0.63
Benzene - 0.011
10 0.06
Carbon Tetrachloride 2.1 0.07 ND
Chlorobenzene 720 1.7 -- - 0.014
Ch10r0fonn 45 0.4 ND
Etbv1benzene 3600 13 0.46
Methvlene Chloride 37 0.03 0.026
Toluene 7,200 30 0.025
Trichloroethylene 25 0.08 0.01
Xylenes (total) 70 000 80 4.4
Alpha.BHC 0.044 0.0' ND
Endosulfan II : 1.8 0.29 0.022
Toxaphene 0.25 76 j::tl:I:II:::I::::ij.I:II::::::::::I::~::j~::::
DioxinlFurans (TEF) 0.001' 0.14 3.5 X 1~
c.
Surface soil remediation target concentrations are based on future residential land use (i.e., unlimited
exposure). Surface soil are defined as those which extend to twelve inches below surface. -Remedial action
target concentrations-based on a carcinogenic risk of 1 x 10-6 or a hazard index of _1.0.
Subsurface soil remediation target concentrations are based on future commercial land use (i.e. limited
exposure) for inorganic constituents, and are based on a carcinogenic risk of 1 x 10-6 or a hazard index of 1.0.
Oiganic constituent target concentration are based on leaching potential.
Values are for surface and subsurface soils.
Beryllium detection observed in subsurface soil and does not exceed remediation target concentrations for
subsurface.
Copper target concentrations based on a reference dose calculated from the MCLG of 1.3 mg/l. -
Lead target concentration based on OSWER directive 9355.4-02.
Dioxins'Furans target concentration from EPA Dioxin Disposal Advisory Group.
Remediation target concentration exceeded for constituent. -
a
b
d
g
22
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TABLB 6-5
BSTIMATED VOLUMES OF AFFBCTED MATBRLALSa
MEDIUM
VOLUMB EXCBBDING RBHBDIATION
TARGBTS (Yd3)
24,000
13,500-
Sludge b
Surface Soil
Overburden
Subsoil
31,000
18,000
a
Volumes of soil and sludge are calculated as8in-place8 or
undisturbed volumes; excavation and transportation processes tend
to increase the total volume of soil by as much as 50%, depending
on soil type, moisture content, and degree of compaction. Volumes
based on piezometer measurements.
All sludge is assumed to exceed target concentrations for
tc»caphene.
b
GROUNDWATER
Currently, monitoring well N-6SR has indicated toxaphene contamination
at a level of 0.069 ppm (the MCL is 0.003 ppm), well N-5 and KV-5
indicate benzene at levels of 0.13 ppm and 0.011 ppm respectively (the
MCL for benzene is 0.005 ppm), and KV-3 indicates nickel
contaminatiqn at a level of 0.186 ppm (the MCL for nickel is 0.1 ppm).
See Figure 6-1 for monitoring well locations. Since groundwater
contamination is currently limited to a solitary but different
contaminant in separate monitoring wells, alternatives for groundwater
remediation are not necessary at this time. However, both onsite and
off-site monitoring of groundwater, surface water, and sediment (both
in the onsite pond and in the adjacent drainage ditch) will continue.
Monitoring of groundwater and surface water will be a part of any
alternative chosen. If toxaphene begins to migrate off the Hercules
009 Landfill property, if the other contaminants of concern migrate
from the current contaminant locations, if any levels of contaminants
of concern begin to increase over fifty percent of their current
. value, or in case it becomes apparent that onsite levels of
contaminants in the groundwater will not naturally attenuate below
MCLs in a time frame comparable to a pump and treat system, a
contingency pump and treat system will be implemented. Measurable
attenuation of groundwater contamination must be achieved within 5
years after the. completion of the soil remedy for the final operable
unit for this Site. During Remedial Design interim goals will be
devised for groundwater contaminant levels which indicate at what
levels natural attenuation would be expected to reach. Such interim
goals will be established for annual intervals. If two consecutive
interim goals are not met, a groundwater pump and treat system must be
23
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initiated. The groundwater will be pumped to the surface and treated
onsite with granular activated carbon. The spent granular activated
carbon will be sent to a hazardous waste facility for disposal. The
treated groundwater will be discharged to a local publicly-owned.
treatment works. If a discharge permit cannot be obtained~ an NPDES
permit for discharge to an off-site surface water body will be
obtained. If an N~vES p~rmit cannot be obtained, onsite discharge to
the onsite pond will be considered. If MCLs are met for two.
consecutive annual monitoring periods, groundwater sampling may be
discontinued at the discretion of EPA. Proper abandonment of the
wells replaced during OU#2 will be implemented if the well owners are
amenable to abandonment. .
7.1
ALTERNATIVE No.1 - No-Action
The No-Action Alternative is carried through the screening process as
required by the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP). This alternative is used as a baseline for
comparison with other alternatives that are developed. Under this
alternative, EPA would take no action to minimize the impact
contamination has on the area. Contamination would remain and
possibly migrate. The present-worth cost for this alternative is
$1,600,000 due to the continued monitoring activities that would
occur.
The No-Action Alternative is retained as the baseline"case for
comparison with other alternatives. No remedial actions would be
performed on either of the media of concern (soil or sludge) at the
Site. The landfill and affected soil areas, as defined during the RI,
would remain in their present condition. The only active component of
this alternative is long-term groundwater, surface water, and sediment
monitoring. This program would be implemented to assess the effect of
waste constituents on the Site.
Groundwater, surface water, and sediment (in both the onsite pond and
the adjacent drainage ditch) at the Site would be sampled and analyzed
annually for site-specific chemicals of concern. The surface water,
sediment, . and groundwater monitoring program would be reevaluated
every five years to assess the appropriateness of the sampling
program. Many of the existing wells at the Site would be used to
. monitor groundwater quality; however, installation of more wells is
probable.
Surface soil monitoring would be performed annually for site-specific
chemicals of concern to evaluate. possible migration. of waste
constituents. Surface soil samples would be collected from potential
drainage areas at the Site. As with groundwater monitoring, a 30-year
period ha.s been used as a basis for cost estimation.
7.2
ALTERNATIVE No.2 - Institutional Controls and Fencinq
The Institutional Controls and Fencing Alternative establishes
24
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institutional measures to block possible waste constituent exposure
pathways through the affected media: soil and sludge. These
inst~tutional measures include the following:
.
long term monitoring as presented in_Alternative 1,
.
fencing to limit access to affected solid materials, and
.
deed restrictions to control future land use.
Institutional controls for the affected surface soil and sludge at the
Site would be implemented by. restricting access to affected Site areas
with additional security fencing and use of deed restrictions. Those
areas of the Site containing surface soil and sludge with waste
constituent concentrations exceeding remedial action target
concentrations would be re-fenced. The replacement-fence would
consist of six-foot high chain-link with at least one strand of barbed
wire extending along the top. The Site would be posted and gates
would be 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 property is transferred to another owner.
Institutional controls for groundwater at and downgradient of the 009
Landfill Site would consist of continued groundwate~monitoring as
described in Alternative 1 and measures that would limit access to
groundwater from the Site. Access to Site groundwater would be
restricted by security fencing and deed restrictions that would
preclude future use by the current or any subsequent land owners.
Analysis of water quality in wells supplying private homes in the
vicinity of the Site indicated no hazardous constituents above
background concentrations. In accordance with the interim ROD for the
Site, public water will continue being supplied to these homes. Long-
term monitoring of the Site would be conducted as described in
Alternative 1,. No-Action.
7.3
ALTERNATIVE No.3 - RCRA Cap of Sludqe and Consolidated Surface
Soil
This alternative combines the actions described in Alternative 2 -
Institutional Controls and Fencing, with excavation and consolidation
of affected. surface soil into the existing landfill, -followed by the
installation of a RCRA Cap. This alternative would contain onsite the
total volume of affected solids.
The purpose of containment is to reduge contact by receptor
populations and the environment with Site waste constituents. This
reduction would be accomplished by minimizing downward vertical
migration of waste constituents due to rain infiltration, preventing
erosion of affected Site materials, and providing a barrier to direct
contact between potential receptors and the affected materials. The
cap would cover the consolidated surface soil containing toxaphene at
25
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concentrations exceeding the surface soil remedial action target of
0.25 parts per million (ppm). Areas excavated for consolidation of
surface soil would be covered with two feet of clean, compacted,
native fill. The total area to be covered with a multimedia RCRA cap
is approximately 7.5 acres. Approximately 10 acres of the Site would
be disturbed by construction activities.
. Containment .would leave affected subsurface soil and sludge in place
with little or no disturbance. A RCRA cap over consolidated surface
materials would minimize contact between percolating water and waste
constituents, thereby reducing the potential for migration of waste
constituents to the groundwater. In addition, a cap installed over
the affected materials would prevent erosion of waste constituents by
wind or surface water runoff. Areas of the Site requiring containment
would be graded to divert surface drainage around and away from the
contained solids. A containment cover of this type would require
periodic maintenance and inspection.
The following design option considered for containment in this
alternative is a multimedia (RCRA) cover over sludge and consolidated
soil. The multimedia cover option would include a cap design for the
landfill disposal area consisting of the following components:
6 inches of topsoil
.
.
18 inches of clean soil
.
1 layer of geotextile fabric
.
6 inches of drainage material (gravel)
1 layer of flexible membrane liner
.
.
2 feet of clay
The multimedia cover option would include a cap design as described
for the areal extent of the existing iandfill (approximately 7.5
acres). Surficial soil exceeding target cleanup levels of 0.25 ppm
would be consolidated to within the confines of the existing landfill.
.The multimedia cover design would comply with GaEPD requirements for
hazardous waste cover systems and would be designed to perform in
accordance with EPA minimum technology guidance. The multimedia cover
would be graded to promote surface drainage and sown with shallow-
rooted grasses.
ALTERNATIVE No.4 - In-Situ Stabilization of Sludqe and
Consolidated Surface Soil with Installation of a Cover
7.4
Alternative 4 consists of the treatment of affected surface soil and
sludge in place by in-situ stabilization. The affected surfacp soil
will be.excavated and then consolidated by placing this soil back on
26
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the 009 Landfill. This alternative involves the stabilization of
subsurface soil, sludge and consolidated surface soil, followed by the
installation of a cover.
The surface soil remedial action target concentrations shall be used
to determine the vertical and horizontal excavation boundaries for
surface soil. The subsurface soil target concentrations were used to
establish treatment boundaries for sUbsurface soil and wastes for cost
estimating purposes. A sampling program would be ~onducted to
determine the actual volumes of surface soil and subsurface soil
requiring remedial action.
In this alternative, subsurface solids and consolidated surface soil
would be treated in place within the landfill. A cover would be
placed over the consolidated, stabilized soil to reduce rainwater
infiltration and direct contact with the treated soil. In addition,
areas excavated for consolidation of surface soil would be graded and
covered with clean, compacted, native fill. Treatment boundaries
would approximate the remedial action limits shown on Figure 9-1.
The incremental risk after implementation of this treatment option
would be 1.~ x 10-6 for carcinogenic effects and 0.0003 for the hazard
index for a child residing near the Site.
This option includes the use of deep soil mixing eqU~pment that
delivers stabilization reagents to the affected solids during mixing
operations. The process involves augering into the affected solids to
the desired depth using hollow-stem augers. The hollow-stem augers
overlap and can vary from two to five augers per assembly. A shallow
soil mixing system is also available and uses a single, wide diameter
auger rather than an assembly of overlapping augers. Treatment agents
are injected into the disturbed matrix through jets constructed in the
auger blades. The reagents can be injected in either a dry, liquid,
or slurry form.
A system such as this would consist of the following typical unit
operations:
.
Shallow Soil Mixing Assembly
.
Reagent Containers and Feed Systems
Drilling depths are limited, but depths up to 30 feet are reportedly
attainable. Treatment duration will vary by depth and by the amount
of mixing required to ensure adequate stabilization. Treatability
studies would be necessary during the remedial design phase to select
the optimal reagent composition and form. Testing of the solidified
treatment zones would also be necessary to ensure that performance
requirements are being met.
27
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ALTERNATIVE No.5 - Excavation, Treatment, and Onsite Disposal of
Sludqe, Subsurface Soil, and Consolidated Surface Soil Followed
by Installation of A Clay Cover
Alternative 5 COI!~ists of excavation of affected solid materials;
onsite treatment of affected solid materials using chemical
extraction; and backfilling of treated residuals into the excavations.
7.5
For the solid waste materials, the first step in tnis alternative
would include the excavation of surface soil and sludge having waste
constituen~s exceeding the appropriate surface soil and subsurface
soil target concentrations for toxaphene of 0.25 ppm and 76 ppm,
respectively. The sludge would be excavated down to the underlying
bentonite layers at a minimum. Following excavation, the affected
materials would be temporarily stockpiled onsite for processing prior
to treatment. The solid waste material requiring treatment is
estimated to consist of approximately 42~000 in-place cubic yards of
affected soil and sludge. The estimated surface soil, sludge, and
subsurface soil quantities are listed in Table 6-5. Since exposure
to subsurface soil is limited, the volume of subsurface soil exceeding
limited exposure targets is used. A sampling program would be
conducted prior to excavation to determine the actual volumes of
surface soil and overburden requiring remedial action. Sludge may
require dewatering prior to treatment. Treated soli~ would be
disposed of by backfilling the excavations. A layer of clean native
soil will be placed over the treated residuals. In addition, areas
excavated for consolidation of surface soil would be covered with
clean, compacted, native soil.
For cost estimation purposes, chemical extraction is assumed to result
in a 35-percent volume increase over the in-place soil volume. Field
trials may be required to confirm full-scale treatment effectiveness
and to determine the physical and chemical characteristics of the
treated residuals.
Each of the treatment process options would require preprocessing of
the solids to remove .oversized debris and to further reduce the
particle size of the matrix. The cost and economic analysis of this
alternative is based, in part, on the assumption that a small portion
of the total mass of solids would be rejected during preprocessing. A
one-percent rejection rate has been used as the basis. for this
assumption. Because of the uncertain regulatory status of this bulk
debris, the assumption has also been made for cost estimation purposes
that these rejected materials would require off~site disposal as a
RCRA-regulated hazardous waste in an EPA approved landfill.
Chemical extraction is a batch process in which soil or sludge is
thoroughly mixed with successive rinse solutions formulated to remove
amenable fractions of waste constituents from the soil and inert
particles. The aqueous phase is then separated from the solid matrix
by decanting. The rinsate from this step is typically treated using
28
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conventional wastewater technology for metals removal, such as pH
adjustment, flocculation, clarification, and dewatering. Rinse water
is typically recYcled after completion of the treatment cycle. Rinse
solutions for chemical extraction include acid and caustic solutions.
An appropriate extraction solution for the 009 Landfill chemicals of
concern will be selected during treatability studies.
The permit requirements for a chemical extraction system generally
depend on the need for discharging the treatment process rinse water
off-site. The solids generated during treatment of the wastewater
typically are characterized as a RCRA hazardous waste and must receive
further tre~tment. and/or be disposed of as such. Process wastewaters
would be temporarily stored in onsite tanks until reCycled.
Wastewater sludge would be dewatered and stockpiled, if necessary.
Dewatered sludge would be transported to an appropriate EPA approved
facility for treatment and landfill disposal. Treatment of the
process rinse water and dewatered sludge would be further defined
during the remedial design stage of the project.
A typical chemical extraction system consists of the following unit
operations:
. . Material processing/sorting
.
Reagent storage
.
Solids mixing
o
Solids reaction
.
Decanting and solids washing
.
Reagent recycling and reconditioning
One vendor's estimate of chemical extraction throughput for Hercules
was 150 tons per day per module. The overall throughput could be
varied by operating several chemical extraction units in series. For
42,000 in-place cubic yards (63,000 tons) of affected solids, a
chemical extraction operation of 7 days per week would reqJire 60
weeks of operation.
8.0
SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
This section of the ROD provides the basis for determining which
alternative provides the best balance with respect to the statutory
balancing criteria in Section 121 of CERCLA and in Section 300.430 of
the NCP. The major objective of the Feasibility Study was to
develop, screen, and evaluate alternatives for the remediation of
Operable Unit One at the Hercules site. The remedial alternatives
selected from the screening process were evaluated using the following
nine evaluation criteria:
29
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.
Overall protection of human health and the environment.
.
Compliance with applicable and/or relevant Federal or State
public health or environmental standards.
.
Long-term €ffectiveness and permanence.
Reduction of toxicity, mobility, or volume of hazardous
substances or contaminants.
.
.
Short-term effectiveness, or the impacts a remedy might have
on the community, workers, or the environment during the
course of implementing it. .
.
Implementability, that is, the administrative or technical
capacity to carry out the alternative.
.
Cost-effectiveness considering costs for construction,
operation, and maintenance of the alternative over the life
of the project, including additional costs should it fail.
.
Acceptance by the State.
.
Acceptance by the Community.
The NCP categorizes the nine criteria into three groups:
( 1)
(2 )
(3)
Threshold Criteria - overall protection of human health and
the environment and compliance with ARARs (or invoking a
waiver) are threshold criteria that must be satisfied in
order for an alternative to be eligible for selection;
Primary Balancinq Criteria - long-term effectiveness and
permanence; reduction of toxicity, mobility, or volume;
short-term effectiveness; implementability, and cost are
primary balancing factors used to weigh major trade-offs
among alternative hazardous waste management strategies; and
Modifvinq Criteria - state and community acceptance are
modifying criteria that are formally taken into account
after public comment is received on the proposed plan and
incorporated in the ROD.
The selected alternative must meet the threshold criteria and comply
with all ARARs or be granted a waiver for compliance with ARARs. Any
alter~ative that does not satisfy both of these requirements is not
eligible for selection. The Primary Balancing Criteria are the
technical criteria upon which the detailed analysis is primarily
based. The final. two criteria, known as Modifying Criteria, assess
the public's and the state agency's acceptance of the alternative.
Based on these final two criteria, EPA may modify aspects of a
specific alternative.
30
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TABLE 8-1
COMPARATIVE ANALYSIS OF ALTERNATIVES
HERCULES 009 LANDFILL FEASIBILITY STUDY
Alternative 4 Altemative 5
Altemative 3 \ In-Situ Stabilization of ' Excavation, Chemical
RCRA Capping of Sludge and Consolidated Extraction, and Onslte
Alternative 1 Altemative 2 Sludge and Consolidated Surface Soil with Disposal of Sludge and
No-Action Institutional Controls Surface Soil Multimedia Cover Surface Soil with Clay
Cover
Description Assumes current Establish deed Excavate and consolidate In-Situ stabilize sludge. Excavate and stockpile
Site conditions restrictions and affected surface soli to Excavate and consolidate sludge and affected
construct additional area of landfill. Grade and affected surface soil. surface soil. Treat with
fencing. install RCRA cap over Stabilize surface soil. chemical extraction
sludge and affected soil. Grade and install (B.E.S.T.) and backfill
Establish deed restrictions Multimedia cover. residuals. Grade and clay
and construct additional Establish deed cover treated soil.
fencing. restrictions and construct Establish deed restrictions
additional fencing. and construct additional
fencing.
Criteria
Overall protection of No change in This alternative would This alternative would This alternative would This alternative would
human health and existing conditions. result in an upper bound result in an upper bound result In an upper bound result In an upper bound
the environment The current land use excess cancer risk of excess cancer risk of 1.0 excess cancer ri9k 1999 exces9 cancer risk of 1.0 x
base line ri9k 3.1 x 10" and a hazard x 10" and a hazard Index than or equal to 1.0 x 10" 10" and a hazard index of
assessment resulted index of 3 x 10" for of 3 x 10" for and a hazard index of 3 x 10" for
In an upper bound noncarcinogenic effects. noncarcinogenic effects. 3 x 10" for noncarcinogenic effects.
exces9 cancer risk Thi9 alternative serves noncarcinogenic effects. This alternative Is
of 3.8 x 104 and a to prevent direct contact This alternative provide9 permanent, but the 9hort-
hazard index of 6.1 with the 9ame surface permanent removal of the term risk 19 greator than
for noncarcinogenic area; however, this affected solid9 requiring that of all the other
effects. remedy has little remedial aption, but the alter~ative9.
permanence. I short term ri9k is '
, increased over Alts. 1
and 2.
Compliance with Does not comply Does not comply with Will meet ARARs. Will meet ARARs. Will meet ARARs.
ARAR9 with ARARs. ARARs.
31
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Alternative 4 Alternative 5
Alternative 3 In-Situ Stabilization of Excavation, Chemical
RCRA Capping of Sludge and Consolidated Extraction, and Onsite
Alternative 1 Alternative 2 Sludge and Consolidated Surface Soil with . Disposal of Sludge and
No-Action Institutional Controls Surface Soil Multimedia Cover Surface Soil with Clay
Cover
long-term None. Will be effective in Will Increase pro~tion\ Stabilization will increase' Treatment will remove
effectiveness controlling direct contact . over. that provided by All protectiveness over that waste constituent source
pathway and preventing 2 by eliminating risk of provided by Alt. 2 and 3 areas, and cover will
future development of direct contact. by immobilizing waste control direct contact
the Site. constituent sources. pathways with treated
Multimedia cover will residuals, providing long'
provide additional term effectivenass.
protectiveness for cirect
contact with treated
residuals.
Reduction of toxicity, None. None. None. Treatment will immobilize Treatment will eliminate
mobility, or volume source material. waste constituent source
areas.
Short-term No effect on the Will provide degree of Site disturbances are Site disturbances are Site disturbances are
effectiveness environment in the effectiveness manageable. Volume of manageable. Volume of manageable. Volume of
short term. Provides approximately equal to truck traffic reduces short- excavated material Is not excavated material
greatest dagree of that of Alt. 1. term effectiveness. significar\l significantly reduces short-
short-term term effectiveness.
effectiveness.
Implementability Readily Equal to Alt. 1. Includes only proven Stabilization of sludge is Chemical extraction of
Implementable using technologies. No off-site proven technology at toxaphene wastes Is
existing technology. TSD facility required. other sites and in Site- proven by treatability
specific treatability studies. Off-site disposal
studies. No off-site facility Is required for
disposal facility required. extract. May require
dewatering. Site boundary
limitation will restrict
I excavation effectiveness
I
Cost low Range low Range low to Medium Range Medium Range High Range
-------
The following analysis is a summary of the evaluation of alternatives
for remediating the Hercules Superfund Site under each of the
criteria. A comparison is made between each of the alternatives for
achievement of a specific criterion.
Threshold Criteria
8.1
Overall Protection of Human Health and the Environment
The No-Action Alternative does not modify or reduce the potential for
human exposure. Nonetheless, to monitor the potential exposure from
ingestion Qf drinking water, the groundwater, surface water, and
sediment sampling and analyses program is established to evaluate
potential future exposures. Implementation of this alternative will
not result in exposure of neighboring residents to unacceptable risks
from the 009 Landfill Site. The estimated upper bound lifetime excess
cancer risk calculated for future land use scenarios at the 009
Landfill Site is 3.8 x 10-3 for the reasonable maximum exposure
conditions. The associated hazard indices for noncarcinogenic effects
under this same scenario is 6.1. The carcinogenic risk factor exceeds
EPA's guideline range of 1 x 10-4 to 1 X 10-6 excess lifetime cancers
in humans as promulgated in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP) , 40 CFR Part 300. A hazard index
greater than 1.0 for noncarcinogenic health effects indicates that
sensitive individuals may exhibit adverse effects afcer direct contact
with the affected soil and use of shallow groundwater at the Site for
a drinking water source.
Alternative #2 is protective of human health and the environment at
the 009 Landfill Site because future exposure to waste constituents
will be reduced by legal restrictions imposed on future land use. The
maximum additional risk posed by direct contact with affected soil
off-site will be 3.8 x 10-3 for carcinogenic constituents, and the
hazard index will be 0.0003.
Alternative #3 will provide overall protection of human health and the
environment. Exposure from direct contact and inhalation with
affected soil and dusts will be minimized by a multimedia cap
constructed with soil, gravel, a geotextile fabric, and clay. The
reasonable maximum exposure after implementation of this alternative
at the 009 Landfill Site will be 1.0 x 10-6. Incremental risk
between 1 x 10-4 and 1 x 10-6 is within the range considered acceptable
by the EPA. The hazard index for noncarcinogenic constituents will be
0.0003 for the reasonable maximum exposure after capping. A hazard
index exceeding 1.0 is considered significant.
The RI indicated that migration of waste constituents from the
landfill has been limited to the immediate surrounding soil.
Consolidation of surface soil exceeding target toxaphene
concentrations of 0.25 ppm will reduce direct contact exposure.
Construction of a low-permeability cap over the landfill areas will
further decrease the potential for direct contact exposure and the
33
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potential for migration from the disposal area by reducing the
infiltration of precipitation. Groundwater quality will be monitored
by a long-term sampling and analysis program. Similarly, soil samples
from drainage areas will be collected during the long-term program to
assess the effectiveness of the cap in preventing the migration of
waste constituents by erosion pathways.
The minimum level of overall protection provided by in-situ
stabilization (Alternative #4) is 1.0 x 10-6 for the lifetime excess
cancer risk and 0.0003 for the hazard index. The additional
protection offered by in-situ stabilization/solidification is further
enhanced by-the short-term protectiveness gained from treatment
without excavation of waste materials. Furthermore, -the risk of
potential releases off-site during transportation to, and disposal at,
a TSD facility will be eliminated by this alternative. However,
short-term protectiveness will be somewhat diminished during
construction activities that consolidate affe~ted surface soil with
waste areas.
In-situ treatment could still result in emissions of waste
constituents from dust and volatilization due to the treatment process
and erosion-from areas awaiting treatment. These risks have not been
quantified. However, the additional risks would be significantly less
than those for alternatives that require excavation. Standard
engineering practices for dust and erosion control will be implemented
to control these migration pathways.
. .
Alternative #5 will provide overall protection of human health and the
environment. Source excavation and treatment will minimize the
potential for future migration of waste constituents to human
receptors and the environment in and around the 009 Landfill Site.
Long-term exposure from direct contact with, and inhalation of,
affected soil and dusts will be minimized by treatment of all affected
soil and. sludge. This alternative would reduce the incremental risk
posed by direct contact to 1.0 x 10-6. The hazard index would be less
than or equal to 0.0003 for any specific constituent, because the
removal target levels of the sludge and affected soil limits risk to
these values. These' risk values are well below EPA's goal of a
carcinogenic risk of less than 1 x 10-4 and a hazard index less than
1.0.
8.2
Compliance with ARARs
The remedial action for the Hercules Site, under CERCLA Section
121(d), must comply with federal and state environmental laws that are
either applicable or relevant and appropriate (ARARs). Applicable
requirements are those standards, criteria or limitations promulgated
under federal or state law that specifically address a hazardous
substance, pollutant, contaminant, remedial action, location or other
circumstance at a CERCLA site. Relevant and appropriate requirements
are those that, while not applicable, still address problems or
situations sufficiently similar to those encountered at the site that
34
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their use is well suited to the particular site. To-Be-Considered
Criteria (TBCs) are non-promulgated advisories and guidance that are
not legally binding but should be considered in determining the
necessary level of cleanup for protection of health or the
environment.
While TBCs do not have the' status of ARARS, EPA's approach to
determining if a remedial action is protective of human health and the
environment involves consideration of TBCs along w~th ARARs.
The affected groundwater in the aquifer beneath the Hercules Site has
been classified by EPA as Class IIA for the surficial aquifer. Class
IIA groundwater is a current source of drinking water. It is EPA's
policy that groundwater resources be protected and restored to their
beneficial uses. A complete definition for groundwater classification
is provided in the Guidelines for Ground-water Classification under
theEPA Ground Water Protection Strateqy, Final Draft, December 1986.
Location-specific ARARs are restrictions placed on the concentration
of hazardous substances or the conduct of activities solely on the
basis of location. Examples of location-specific ARARsinclude state
and federal-requirements to protect floodplains, critical habitats,
and wetlands, and solid and hazardous wast~ facility siting criteria.
Any remedial measures that involve activity in the adjacent drainage
ditch would require a wetlands permit, due to discharge of dredge and
fill materials in to waters of the United States. Alternatives
involving excavation of landfill constituents would likely impact the
adjacent ditch given its close proximity. Table 8-2 summarizes the
pot'ential location-specific ARARs and TBCs for the 009 Landfill Site.
Some remedial alternatives could be limited by the location
requirements for new or existing facilities.
Action-specific ARARs are technology- or activity-based requirements
or limitations on actions taken with respect to hazardous wastes.
These requirements are triggered by the particular remedial activities
that are selected to accomplish a remedy. Since there are usually
several alternative actions for any remedial site, various
requirements can be ARARs. Table 8-3 lists potential action-specific
ARARs for the selected remedy for the Hercules 009 Landfill Site, and
Table 8-4 lists potential action-specific ARARs for the contingent
.remedies (for both source control and groundwater) for the Hercules
009 Landfill Site.
The RCRA Land Disposal Restrictions (LDRs) are potential ARARs for
remedial actions on the sludge and soil at t~e 009 Landfill Site. The
LDRs are applicable to remedial actions that involve A placement " of
restricted RCRA hazardous waste. The area of contamination (AOC) at
this Site consists of the Hercules property commonly known as the 009
Landfill, including all of the landfilled sludge cells, the staging
area located near the landfilled sludge cells, plus the length of the
drainage ditch where the ditch is adjacent to the Hercules property,
the soil on the banks of the drainage ditch, the Benedict Road/Nix
35
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TABLII 8-2
POTD1TUL LOCAT%OIIt SP8C%W%C AltAR.
Location Citation
A Critical habitat upon Endangered species Act of 1973
which endangered or (50 CFR Part 200 and Part 402)
threatened species Fish and wildlife coordination Act -
depends (33 CFR Parts 320-330
Georgia EPD 391-4-10
R&A Within 100-year General RCRA Facility Location Standard
floodplaln (40 CFR 264.18[bJ;
TSCA requirements
(40 CFR 761. 75)
Georgla Facility Location Standards
(391-3-4)
Protection of floodplain -
(40 CFR 6, Appendix AI
Fish and wildlife Coordination Act
(40 CFR 6.302)
TSCA (40 CFR 761.75)
R&A Potential for National Historic Preservation Act,
irrepa~ble harm, loss, Section 106
or destruction of 36 CFR Part 65 and Part 800
significant artifacts Georgia EPD 391-5-9 and 391-5-8
R&A Wetlands Fish and wildlife Coordination Act - -
(40 CFR 6.302)
Georgia EPD 391-3-16-.03
Clean Water Act, Section 401 and 404
Rivers and Harbors Act
Georgia Coastal Marshlands Protection Rules (391-2-3)
R&A Area affecting stream or wild and Scenic River Act
river ~40 CFR 6.302(e»
R&A Within area affecting Wild and Scenic River Act
wild, scenic or Georgia EPD 391-3-6-.03
recreational river
A= APPLICABLE REQUIREMENTS WHICH WERE PROMULGATED UNDER FEDERAL LAW TO
SPECIFICALLY ADDRESS A HAZARDOUS SUBSTANCE, POLLUTANT, CONTAMINANT, REMEDIAL ACTION
LOCATION OR OTHER CIRCUMSTANCE AT THE HERCULES SITE.
R &: A = RELEVANT AND APPROPRIATE REQUIREMENTS WHICH WHILE THEY ARE NOT
"APPLICABLE" TO A HAZARDOUS SUBSTANCE, POLLUTANT, CONTAMINANT, REMEDIAL ACTION,
LOCATION, OR OTHER CIRCUMSTANCE AT THE HERCULES SITE, ADDRESS PR9BLEMS OR
SITUATIONS SUFFICIENTLY SIMILAR TO THOSE ENCOUNTERED AT THE HERCULES SITE THAT
THEIR USE IS WELL SUITED TO THE SITE.
36
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!'ABL8 8-3
S8L8C'1'SD aDIED'r.
POTDI'l':E&L CBDaCAL-SP8CDXC AIlE) ACl'XC8I-SP8CX.XC AIIAIt8
BAR IaDllt:DlO 1IA'I'D AC'f - .0 use l18C~lOD 300
A 40 CFR Part 141 - National Primary Drinking Establishes maximum contaminant levels (MCLs) which
Water =~andards are health-based standards for public water systems.
A 40 CFR Part 141 - Maximum Contaminant Level Establishes drinking water quality goals set at
Goals (MCLGs) levels of no known or anticipated adverse health
effects with an adequate margin of safety.
CLUR WA'I'D AC'f - 33 U. S. C. 1251-137'
R & A 40 C~R Part 131 - Ambient Water Quality ~ggested ambient standards for the protection of
Criteria requirements uman health and aquatic life.
RUOORa COJf88ItVATXC8I AIm It8COVDT ACr - .2 U.B.C. 45101-"87
A1 40 CFR Part 241 - Guidelines for the Land Establishes minimum levels of performance required of
R & A, Disposal of Solid Wastes any solid waste land disposal Site operation and
includes operation and maintenance.
R & A 40 CFR Part 261 - Identification and Defines those solid wastes which are subject to
Listing of Hazardous Wastes regulation as hazardous wastes under 40 CFR Parts
263-265 and Parts 124. 270. and 271.
40 CFR Part 264 - Standards for Owners and Establishes minimum national standards which define
R & A Operators of Hazardous Waste Treatment, he acceptable management of hazardous wastes for
Storage and Disposal (TSD) Facilities owners and operators of facilities which treat, store
Georg.ia-3-4 or dispose of hazardous wastes.
40 CFR Part 268 - Land Disposal Identifies hazardous wastes that are restricted from
A1 51 FR 40641 land disposal and describes those circumstances under
R & A, 52 FR 25760 . ",hich an otherwise prohibited waste may be land
RCRA sections 3004(d) (3), & (e) (3) disposed. - -
Georgia EPD 391-3-11-.16
CLUR An.ACT
A 40 CFR Part 61 - National Emission ~fresses hazardous air pollutants at their point of
tandards for Hazardous Air Pollutants ission fram specific sources
I!. - APPUCA8I.£ REQUIKEMENTS WHlOf WERE PROMUI.CATED UNDER FEDERALIJ\WTO SPECIFlCA!.l.Y ADDRESS A IUZAAOOUS SUBSTANCE. POlLUTANT. CONTAMINANT. REMEDIAl. ACTION
LOCAnON oJ! 0lJfEII CIICIlMSTANC£ AT na: HEllCUU:S $lTE.
R & A . KEUVANT AND Al'nDPRJAT£ KEQUIKDIENI'S WHICH WKIU: na;y ~ HOT 'APPUCABI.£' ro A HAZARDOUS SUBSTANCE. POUUT ANT, CONTAMINANT, /IEMEIXAL ACJ1OH,
LOCAnON,oJ! 0lJfEII CIICIlMSTANC£ AT na: HEIIcuu:s SITE. ADDJIESS PIt08I.aCSOR smlA710HS SUFFJaENTLY SIMIIJ\JI TO 7JfOSE ENCOUNTfJIED AT 7JfE HEKCUI.£S SITE 7HAT THEIR USE
IS WEI.I. SU1T£D TO 7Jf£ $lTE.
- OfEMICAI.-sncmc: 1IlQUIR£M£NT
12 . ACTION-5P£C1F/C KEQUIR£M£NT
37
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TABLIt '-4
COJITDCDII'1' ""''''D8.
PO'1'DI'1'%AL CBIII%c:AL-SPKCInC AJII) ACT%OH-SPEC%I'%C ARAR8
CL8AH WATU ACT - 33 U. S. C. 1251-1375
40 CFR Part 122, 125 - National Pollutant Requires permits for the discharge of pollutants for
Discharge Elimination System any point source into waters of the United States.
R & A 40 CFR 125
40 CFR 131
40 CFR 136.1
~eorgia EPD 391-3-6-.06
R & A 40 CPR Part 131 - Ambient Water Quality suggested ambient standards for the protection of
Criteria requirements human health and,aquatic life.
A 40 CFR Part 403 - National Pretreatment Sets standards t~ control -pollutants which pass
Standards through or interfere with treatment processes in
public treatment works or which may contaminate
sewage sludge.
USOtJJlCK -
CONSDVAT%OH AJII) RZCOVDY ACT - 42 U.S.C. U01-5!I'7
A, 40 CFR Part 241 - Guidelines for the Land Establishes minimum levels of performance required of
R & Ao Disposal of Solid Wastes any solid waste land disposal Site operation and
includes operation and maintenance.
R & A 40 CFR Part 261 - Identification and Defines those solid wastes which are subject to
Listing of Hazardous Wastes regulation as hazardous wastes under 40 CFR Parts
263-265 and Parts 124, 270, and 271.
R & A 40 CPR Part 262 - Standards Applicable to Establishes standards for generators of hazardous
Generators of Hazardous Waste wastes.
40 CPR Part 263 - Standards Applicable to Establishes standards which apply to transporters of
A Transportation of Hazardous Waste hazardous waste within the U.S. if the transportation
- requires a manifest under 40 CPR Part 262.
40 CPR Part 264 - Standards for Owners and Establishes minimum national standards which define
A pperators of Hazardous Waste Treatment,' the acceptable management of hazardous wastes for
Storage and Disposal (TSD) Facilities owners and operators of faci~ities which treat, store
or dispose of hazardous wastes.
40 CPR Part 268 - Land Disposal Identifies hazardous wastes that are restricted from
A 51 PR 40641 land disposal and describes those circumstances under
52 PR 25760 ~hich an otherwise prohibited waste may be land
RCRA sections 3004(d) (3), & (e) (3) ~isposed.
~eorgia EPD 391-3-11-.16
SAn DRIN1I:!NQ WATU ACT - 40 usc sectl- 300
A 40 CPR Part 141 - National Primary Drinking Establishes maximum contaminant levels (MCLs) which
Hater Standards ~re health-based standards for public water systems.
R & A PL No. 99-339 100 Stat.462 (1986) - Maximum Establishes drinking water quality goals set at
Contaminant Level Goals (MCLGs) levels of no known or anti~ipated adverse health
~ffects with an adequate margin of safety.
CL8AH Am ACT
A 40 CPR Part 61 - National Emission ddresses hazardous air pollutants at their point of
Standards for Hazardous Air Pollutants mission from specific sources
US IlATUIALS TRAHSPORTAT%OH ACT - 4i U.S. ' C 1801-1113
40 CPR Parts 107, 171-177 - Hazardous Regulates transportation of hazardous materials.
A Materials Transportation Regulations
A . APPUCA!II.E JIEQUlREMEN7S WHlOf WEX£ PROMULCATED IlND£II fEDER.AI.IAW TO SPErIl'lCAUY ADDRESS A HAZARDOUS SUBSTANCE. ~urANT, CONTAMINANT. REMEDIAL AC710N
LOCAT10N OR OTHER CIRCUMSTANCE AT THE 1f£RCUL&S StI'£.
R & A . RELEVANT AND APPROPRIATE REQUIREMENTS W/fJCH WHlU:7H£Y ARE NClT 'APPUCABU' TO A HAZARDOUS SUBSTANCE,POWrTANT. CONTAMlNANT,REMEDlALACT10N.
LOCAT10N,OR OTHER ORCUMSTANCE AT THE If£RCUU:S 5lTE.ADDRESS PlWlllEMSOR SITUATIONS 5U1'FlaENTLY SIMlAR TO THOSE ENCOUNTERED AT THE HE/ICUL£S 5lTETHATTHlIR USE
S W£I.L SUITED TO THE StI'£.
1 . Of£MICAL-SPEClI'IC REQUIREMENT '.
2 - ACT10IoJ.SP£C1FJC REQUIREMENT
38
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Lane area which abuts the Hercules property, and contiguous soils
located just southeast of the Benedict Road/Nix Lane area. Land
disposal restrictions are not applicable where banned waste is moved,
graded, stabilized, or treated in-situ, entirely within the original
area of contamination, because placement has not occurred, but may be
relevant and appropriate. Toxicity Characteristic Leaching Procedure
(TCLP) results indicated toxaphene was below detection limits in the
waste extract. The Hercules wastewater sludge generated from the
production of toxaphene is exempt from listing as a hazardous wastes
under RCRA (40 CFR 261) because the sludge was lasE handled in June
1980. Although not applicable, pertinent aspects of RCRA closure
requirements may be relevant and appropriate in Alternative #4 because
a hybrid-landfill closure system will be used. If Alternative #5,
chemical extraction, is utilized, then RCRA closure requirements may
be applicable.
Chemical-specific ARARs are specific numericai quantity restrictions
on individually-listed chemicals in specific media. Examples of
chemical-specific ARARs include the MCLs specified under the Safe
Drinking Water Act as well as the ambient water quality criteria that
are enumerated under the Clean Water Act. Since there are usually
numerous chemicals of concern for any remedial site, various numerical
quantity requirements can be ARARs. Tables 8-3 and 8-4 list potential
chemical-specific ARARs for the 009 Landfill Site.
For Alternative #1, there are no chemical-specific, action-specific,
or location-specific ARARs for the chemicals of concern in soil, if
left in place. Chemical-specific ARARs are listed in Tables 8-3 and
Tables 8-4. Groundwater ARARs include Maximum Contaminant Levels.
(MCLs) that establish chemical-specific limits on certain contaminants
in community water systems. Even though the groundwater data suggests
that representative concentrations of constituents are above the
established MCLs, natural attenuation is expected to achieve MCLs over
time due to the treatment of the source area. Long-term monitoring
based on annual sampling is included in each of the proposed remedial
alternatives. This will allow for a statistical analysis of
additional data to further substantiate the presence/absence of a
groundwater plume. This long-term monitoring will provide the data
necessary for a statistical determination of constituent
concentrations in groundwater. If, in EPA's sole discretion, it
becomes apparent that MCLs will not be met through attenuation, then a
contingency pump and treat remedy will be implemented.
For Alternative #2, there are no action-specific or location-specific
ARARs for the chemicals of concern in soil, if left in place. Based
on the available data, groundwater at the 009 Landfill Site meets
ARARs with the exception of chemical specific ARAR of primary drinking
water standards (MCLs). Additional groundwater sampling and analysis
is necessary to verify that representative constituent concentrations
will meet the MCLs.
The multimedia cover (Alternative #3) will comply with the RCRA
39
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action-specific requirements for capping solid wastes in place. The
cover will be designed to divert surface water runoff from a 24-hour,
25-y~ar storm. The existing six-foot security fence will remain
around the cap to limit Site access. A multilayer low permeability
RCRA cap topped with a vegetative topsoil layer will reduce erosion
and protect the integrity of the clay barrier. Percolation of
rainfall from the bentonite layer was calculated to be 0.0000 inches
when a layer of geomembrane was included in the design. This analysis
was developed using the H.E.L.P. model, which was designed to evaluate
the efficacy of landfill caps. Closure caps such as this also meet
the EPA remedial action criteria of eliminating the potential for
dermal exposure and incidental ingestion of surface soil and sludge.
No definable plume of toxaphene could be identified in groundwater.
The remedial actions include further sampling and analysis of both
onsite and off-site groundwater to verify that groundwater quality
will meet MCLs. .
The multimedia RCRA cap detailed in Alternative 3 is consistent with
landfill closure requirements. The design will also comply with all
other requirements for capping solid wastes in place. Action-
specific, cRemical-specific and location-specific ARARs will be met by
this alternative.
In Alternative #4, consolidation of the surface soil-prior to in-situ
treatment of wastes within the area of contamination is not expected
to require a waiver for the RCRA Land Disposal Restrictions. Although.
the soils are not expected to be hazardous wastes, characteristic
leaching tests will have to be performed to confirm this expectation.
The remedial act'ion will include further sampling and analysis of
groundwater to verify that groundwater beneath the Site will meet
ARARs through attenuation in a reasonable time frame. Surface water
on Site currently meets ARARs. .
In Alternative #5, action-specific ARARs, in particular the Land
Disposal Restrictions of 40 CFR Part 268, will be met by chemical
extraction of contamination from the excavated soil prior to onsite
disposal of the treated soil so that regulatory limits for
characteristic wastes are met. The remedial actions described in this
alternative will include further sampling and analysis of groundwater
to verify that groundwater quality will meet ARARs through
attenuation.. Off-site disposal of the. extracted contamination must
meet pertinent RCRA ARARs.
Primary Balancing Criteria
8.3
Lonq-Term Effectiveness and Permanence
The No-Action Alternative #1
Implementation of the No-Action Alternative will not reduce potential
risks associated with affected Site materials. Affected Site
materials under this alternative may eventually be transported through
40
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slow volatilization, fugitive dust emissions, or surf~ce water runoff.
No engineering controls designed to prevent exposure to affected
materials would be contemplated as part of this alternative.
Groundwater and surface water monitoring would be conducted for five.
years to evaluate potential migration pathways. These measures could
indicate poss~01e movement of constituents from the Site but would not
result in a reduction in the concentration of toxaphene.
Alternative #2
The potential risk posed by materials containing waste constituents
will be reduced after implementation of the Institutional Controls
Alternative. (Alternative #2). . Future land use of the Site for
residential or industrial purposes would not be expetted to occur
after implementation of deed restrictions. Deed restrictions will
prevent development of the Site by current and future owners of the
property. The Institutional Controls Alternative will rely on
additional security fencing at the 009 Landfill Site to prevent direct
exposure to chemicals of concern.
OVer time, concentrations of the organic chemicals of concern may be
reduced by naturally-occurring microorganisms that degrade the organic
wastes. The-extent to which natural degradation of organic
constitu~nts will occur is difficult to accurately estimate without
the results of long-term Site-specific studies. This natural
reduction in organic constituent toxicity or volume is not expected to
significantly reduce the risk levels calculated for the 009 Landfill
Site.
Alternative #3
Implementation of Alternative #3 will result in a decreased long-term
potential for migration of constituents from soil or waste to
groundwater. The potential for migration will be reduced by two
means. A RCRA cap will act to limit infiltration through unsaturated
soil/sludge. Source removal of the affected surface and subsurface
soils in the southeastern corner of tne 009 Landfill will eliminate
any source of toxaphene external to the landfill. Long-term
monitoring will be used to evaluate potential changes in groundwater
and surface soil quality.
The risk from direct contact with affected soil or wastes will be
minimized. Long-term effectiveness will be dependent on appropriate
maintenance of the capped areas. Maintenance of caps has been
demonstrated to be straightforward and effective. The long-term
adequacy and reliability of the cover wili depend on proper
maintenance and inspection of the facility. This alternative will
require annual inspections to assess and correct any damage to the cap
from erosion~ .
The proposed cover is a well-established, proven technology that has
been used for years throughout the RCRA Subtitle C and CERCLA
programs.. A multimedia cap. of soil, gravel, geotextile fabric, and
clay reduces infiltration that might lead to possible leaching of the
41
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underlying constituents.
Even though future land use is not expected to change from current
use, institutional controls at the Site will provide legal restraints
to potential development. Failure of the actions included in this
alternative will pose an incremental risk equal to the No-Action
Alternative, i.e., 3.8 x 10-3 for carcinogenic risk and a hazard index
of 6.1 for noncarcinogenic constituents.
Alternative #4
Long-term effectiveness and permanence will be' significantly achieved
by consolidation and in-situ stabilization of sludge/subsurface and
covering affected surface soil (Alternative #4). The mobility of any
untreated. soil containing low concentrations of waste constituents
will be controlled by covering treated areas with a low permeability,
multilayer cover, followed by seeding to establish vegetative ground
cover and reduce erosion. The cover will also serve to minimize the
effects of weathering on treated materials.
Long-term groundwater monitoring will be included as an element of
this alternative to ensure that low concentrations of toxaphene
remaining iV the soil do not enter a pathway for exposure to the
environment. This monitoring program, coupled with maintenance of the
ground cover, will reduce uncertainties that may be associated with
action levels and construction methods. .
Alternative #5 .
After implementation of Alternative #5, risks posed by Site conditions
will be reduced. The mobility of organic and inorganic constituents
in the excavated sludge and soil will be reduced by chemical'
extraction and disposal of the treated soil onsite. Since direct
contact with the sludge and surface soil posed the primary risk at the
Site, the resulting Site risk will be reduced after source removal and
treatment is completed. The carcinogenic risk level after
implementation of this alternative will be 1.0 x 10-6, and the
corresponding hazard index for noncarcinogenic constituents will be
0.0003. For this risk calculation, it was assumed that the landfill
area was backfilled with treated solids and capped with a low
permeability clay cover.
Long-term effectiveness is maximized by excavation, treatment, and
onsite disposal of all solids treated to achieve waste constituent
concentrations at or below remedial action target levels. Fencing and
long-term maintenance would be required at the Site after
implementation of this alternative, which would provide an additional
degree of permanence due to excavating and treating the affected
solids. Even though future land use is not expected to change,
Institutional Controls at the Site will provide legal restraints to
potential future development.
42
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8.4
Reduction of Toxicity, Mobility or Volume Throuqh Treatment
Under the no-action alternative, toxicity, mobility, and volume will
not be reduced through treatment.
Under Alternative #2, naturally~occurring microorganisms may degrade
the organic wastes over time. This may slightly reduce the toxicity
and volume of constituents. On the whole, however, toxicity,
mobility, and volume will not be significantly reduced by the
Institutional Controls Alternative. -
Implementa~ion of Alternative #3 will not reduce the toxicity or
volume of waste constituents. Mobility will be reduced as a result of
a significant decrease in infiltration and erosion.
For in-situ stabilization (Alternative #4), the mobility of chemicals
of concern will be greatly reduced~ Toxicity will be reduced
incidentally during the stabilization process due to the added
material. A.bench-scale treatability study indicated that the volume
of treated material will increase by 25 percent.
The exposur~ potential of waste constituents will be greatly reduced
by a combination of the following factors:
.
Sludge and soil treatment in-situ,
.
Covering the consolidated, treated, surface soil with a
RCRA-like cover,
.
Covering the surface with vegetation, and
.
Conducting monitoring of groundwater and surface soil.
Implementation of Alternative #5 will reduce the mobility of both the
excavated materials and the remaining soil. The excavated materials
will be treated with chemical extraction to the extent required to
meet hazardous characteristic limits imposed by the LDRs.
Treatability studies of onsite waste indicated that the LDR limits are
achievable. Toxicity and volume will be greatly reduced following
implementation of chemical extraction. This alternative will
completely excavate and treat the volume of affected materials
exceeding target levels.
8.5
Short-Term Effectiveness
Alternative #1
Implementation of the proposed no-action Alternative will have little
or no negative, short-term impact on the local community; the No-
Action Alternative offers the least disturbance of the Site. The
monitoring wells proposed for sampling already exist. All of the
monitoring work required will be completed within the boundary of the
009 Landfill Site. These activities will have a minimal effect on the
43
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adjacent residents.
Workers involved with sampling will wear personal protective equipment
during operations in the vicinity of the waste management area
currently fenced. This will include protective outer clothing, steel-
toed boots with proteqtive overboots, and appropriate work gloves.
Proper use of protective equipment will help ensure short-term
protection of workers.
Because the monitoring wells at the 009 Landfill Site are already. in
place, there will be minimal negative environmental effects from
implementa~ion of this alternative. .
Alternative #2
Implementation of the Institutional Controls Alternative (#2) will
have little or no negative effect on the surrounding community. Even
though fence improvements and construction will take place outside the
affected areas, workers installing the fence will wear personal
protective equipment, during operations. This will include protective
outer clothing, steel-toed boots with protective overboots, and
appropriate gloves. Proper use of protective equipment and safe
construction practices will help ensure short~term protection of
workers.
Alternative #3
Alternative #3 will result in increased airborne dust during the
consolidation of surface soil and construction phases of the project.
Dust control by watering, to minimize airborne particulates, will be
conducted during construction. Air monitoring will also be conducted
during construction to assess the environmental effects of airborne
particles. Potential off-site migration of c~emicals of concern due
to erosion will be limited by the utilization of silt fences during
construction. Fugitive dust emissions and erosion are easily managed
with standard engineering practices. .
Workers involved with construction will wear personal protective
equipment during Site operations. This will include protective outer
clothing, steel-toed boots with protective overboots, gloves, and
respirators. Proper use of protective equipment and safe construction
practices will help ensure short-term protection of workers.
Construction of this remedial alternative is estimat€d to require 15
months to implement, allowing time for design, bidding, construction,
and predictable downtime during Site activities.
Alternative #4
In Alternative #4, approximately 73,000 yards of sludge and soil
containing toxaphene exceeding remedial action target concentrations
will be treated in-situ in conjunction with stabilization of
consolidated surface soil. Approximately 13,500 cubic yards of
affected surface soil will be consolidated by placing these soils upon
the landfill. Consolidation practices that minimize unnecessary
44
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releases of waste constituents to the environment will be used.
Nonetheless, due to the inherent limitations of dust and erosion
control techniques, surface soil consolidation will reduce short-term
effectiveness. Standard engineering practices for dust and erosion
control will be implemented to control these migration pathways.
Transport by surface runoff of sediment containing waste constituents
will be controlled by installation of temporary runoff-diversion berms
and silt fences.
Workers at the Site will wear protective clothing. - This may include
protective outer clothing, steel-toed boots with protective rubber
booties, rubber gloves, hard hats, and eye protection. If necessary
for respiratory protection, the workers will wear face masks equipped
with particulate filters.
Alternative #5
Alternative #5 will result in an increase in airborne dust during the
excavation and treatment phases of the project. Air monitoring will
be conducted during these phases to assess the risks posed by airborne
particulates. Potential off-site migration due to erosion will be
limited by the utilization of silt fences during excavation and
grading. This remedial action will disturb a large area and will be
less effective for the short term than Alternatives 1, 2, 3, and 5.
Standard engineering practices should be capable of managing off-site
migration of dusts and erosion materials.
Workers involved with construction will wear personal protective
equipment during Site operations." This will" include protective outer
clothing, steel-toed boots with protective overboots, gloves, and
respirators. Proper use of protective equipment and safe construction
practices will help ensure short-term protection of workers.
Excavation, treatment, and grading activities associated with this
alternative could take 24 months to implement, allowing time for
design, bidding; excavation, and unforeseen downtime during excavating
and grading. "
8.6
Implementabilitv
For Alternative #1:
All sampling equipment will be available to complete the proposed
program for the no-action Alternative. Trained specialists must
review monitoring results to properly assess implications of water
quality data. It is assumed that adequate analytical laboratory
~apacity will be avai~able during sampling periods. Currently,
technologies required to implement this alternative are available.
The tasks required for completion can be provided by more than one
vendor to allow for competitive bids.
For Alternative #2:
The construction of additional security fencing is technically
feasible. The objective of this alternative is to eliminate the
45
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exposure pathway of direct contact. A.properly-maintained security
fence is a reliable means of controlling Site access. Implementation
of deed restrictions should prevent development of the property by
current and future owners of the Site. The Institutional Controls
Alternative will not be an obstacle to further remedial action. .
Monitoring will include long-term sampling of groundwater, surface
soil, and sludge. If fencing and institutional actions fail to
eliminate exposures to waste constituents, calculated potential risks
posed by'constituents from waste management activities will revert to
those calculated for the No-Action Alternative. Implementation of
this alternative will require minimal interaction with state and
federal agencies.
Acquisition of deed restrictions is administratively feasible.
Because numerous fencing contractors operate in the vicinity of the
Site, contractor availability will not affect the schedule of response
actions. Similarly, the availability of legal assistance for
implementing institutional controls will not affect the project
schedule.
For Alternative #3: .
Construction of a RCRA cap is technically feasible. Construction will
require earth-moving equipment for soil, gravel, clay, top soil cover
material. This alternative relies on well-established and proven
technology. Containment will function reliably, as~ing proper
operation and maintenance of the cap and fence. The cap will not be a
significant obstacle to additional remedial measures in the future, if
necessary. Long-term monitoring will be performed on groundwater and
surface soil. The Site monitoring program will follow methods that
were described for Alternative 1. Monitoring of surface soil is
technically feasible and a reliable means of evaluating potential
surface migration of waste constituents. This has been demonstrated
in numerous settings. Failure of the groundwater monitoring program
will not result in a change in the risk to human health or the
environment, since public water supplies are currently utilized in the
adjoining neighborhood. In the worst case, failure of the surface'
soil monitoring program to detect surface mobility of affected soil
could result in undetected additional risks. However, those risks
would be lower than those calculated in the baseline risk assessment,
since affected materials will be capped and fenced. Implementation of
this alternative will depend on agency approval. The following may be
considered: .
.
Cap design criteria,
.
Monitoring wells and surface soil locations proposed for
sampling,
Analyses to be conducted on samples.
Meeting the substantive requirements of federal, state, or local
permits would delay the initiation of remedial action far less than
.
46
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for alternatives requiring excavation and/or treatment. No off-site
treatment, storage capacity, or disposal (TSD) services will be
required as part of this alternative. It is assumed that construction
materials will be available at the time of construction. The critical
materials will. be clay that meets specification, the geotextile
material, and equipment necessary for installation. Currently,
technologies required to implement this alternative are available.
The work tasks required for completion can be provided by more than
one vendor to allow for competitive bids.
For Alternative #4:
Uncertainties associated with in-situ stabilization are the
variability of treatment throughout the treatment zone and the
incapability of the contractor thereafter to monitor treatment
results. These concerns will be addressed by requiring sufficient
overlap between treatment areas and by post-treatment sampling of the
treated zone and the underlying soil. -
The reliability of in-situ stabilization equipment has been
demonstrated at several sites with inorganic contamination.
Implementation of the treatment process has some level of technical
problems t~t could lead to schedule delays, especially since the
treatment agents must be equally distributed throughout each treatment
area. The depths requiring treatment at the 009 Landfill Site are
well within the range demonstrated during previous applications of
this process at similar sites. However, since organic contamination
is present at this Site, further studies are necessary to determine if
this treatment process will effectively immobilize the organics at
this Site. One bench-scale treatability study has been conducted with
encouraging results. However, a field scale treatability study is
necessary since the average level of toxaphene contamination
(approximately 6000 ppm) is greater than the sample used in the bench
scale treatability study (1200 ppm). Additional analytical tests will
be required.
If treatment results in a solidified mass, additional remedial action,
if necessary, may be difficult to implement. Treatment performance
testing will be conducted to monitor the effectiveness of the remedy.
Long-term groundwater and surface water monitoring will be performed
to evaluate future migration.
This alternative will not require permitting or coordinating with
other offices or agencies. Off-site TSD services will not be required
under this alternative. Special drilling equipment capable of
injecting treatment agents during drilling are required for in-situ
stabilization. However, several vendors offer the process, so the
necessary equipment should be available when needed. Currently,
technologies required to implement this alternative are available.
The tasks required for completion can be provided by more than one
vendor to allow for competitive bids.
47
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For Alternative #5: .
Excavation of source material and grading of the remaining soil will
require earth-moving equipment. Property lines on two sides of the
landfill are within approximately 10 feet of where excavation would
occur. OSHA mandated minimum side slopes cannot be achieved within
the Site boundaries. This would increase the necessity for use of
construction procedures that would complicate the logistics of soil
removal. The possibility that contaminated soil or sludge would be
dispersed on adjacent off-site land would be incre?sed.
This alternative relies on well-established and proven technologies.
Chemical e~tractionof source material is also technically reliable
for the chemicals of concern. A treatability study performed by
Resources Conservation Company indicated that in bench-scale
evaluations toxaphene was removed from 009 Landfill material at an
efficiency of 99.7 percent. If excavation, treatment, and onsite
disposal of the affected solids is the chosen alterfiative, additional
remedial measures should not be necessary. If other remedial measures
are required, there should be no obstacle.
Long-term monitoring will be performed on groundwater. The monitoring
program will follow methods that were described in Alternative 1. If
a migration from the current contaminant locations begins to occur or
the plume does not attenuate below MCLs in a time frame comparable to
a pump and treat system, a contingency pump and treat system will be
implemented. The implementability pump and treat systems have been
demonstrated in numerous settings.
Off-site TSD services may be required as part of this alternative to
dispose of sludge and/or treatment water generated during remediation.
It is assumed that construction materials will be available at the
time of construction. The critical materials will be equipment.
necessary for installation. It is also assumed that chemical
extraction materials and contractors will be available at the time of
excavation. Currently, technologies required to implement this
alternative are available. All of the work tasks required for
completion can be provided by more than one vendor to allow for
competitive bids.
8.7
Cost
As shown by Table 8-5, the cost ranges from $1.6 million to $31
million for the alternatives described. Costs fQr operation and
maintenance during the implementation of the alternative as well as
post remediation monitoring are shown in the table below. Although
Alternative #4, In-Situ Stabilization costs $9.9 million dollars and
is not the cheapest of the alternatives, this alternative does provide
more protection than the cheaper alternatives. In addition, this
alternative satisfies the policy for treatment of the contaminated
media.. However, Alternative #4 is not as expensive as Alternative #5,
which is estimated to cost $31 million dollars. Alternative #5 does
satisfy the prefeLence for treatment and does reduce the toxicity and
48
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TABLB 8-5
COMPARISON OF COSTS
Amlual
Alternative Present- Capital Monitoring
. worth Cost Cost and Risk
Maintenance
Cost (30-
yr)
1. No-Action $ 1,600,000 $163,000 $93,000 3.8 X 10-3
2. $ 1,700,000 $235,000 $ 96,000 3.1 x 10-6
Institutional
Controls
3. RCRA.Cap $ 4,900,000 $3,100,000 $ 119~000 1.0 x 10-6
over Sludge
and
Consolidated
Surface Soils
4. In-&:Ltu $ 9,900,000 $ 8,300,000 $ 104,000 1. ° x 10-6
Stabilization
of Sludge and
Consolidated '.- -
. Surface Soils
with
Multimedia
Cover
5. $ 31,000,000 $29,300,000 $ 97,000 1.0 x 10-6
Excavation,
Chemical
Extraction,
and Om:~ite
Disposal of
Sludge and
Surface Soils
with a Clay
Cover
. mobility of the contaminated media, but the greater ~han three-fold
cost increase is not warranted since Alternative #4 will also protect
human health and the environment'.
Modi~ing Criteria
8.8
STATE ACCEPTANCE
The State of Georgia has concurred with the selection of Alternative
#4 to remediate the contaminated soil at the Hercules site.
49
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8.9
COMMUNITY ACCEPTANCE
Based on the comments expressed at the September 10, 1992 public
meeting and the outpouring of written comments received during the
comment period, it appears that the Brunswick community generally
would prefer that Alternative #5, chemical extraction, be chosen
instead of Alternative #4,' stabilization. The majority of the
comments received did favor Alternative #5; however, a significant
number of comments did favor Alternative #3, capping. Nevertheless,
EPA has determined that Alternative #4 is preferrea because it does
employ treatment and because it will be done in-situ, which will
create les~ disturbance and emissions than Alternative #5. The
increased urbanization of the area is a strong factor to be considered
in deciding whether to implement Alternative #5. Alternative #5
would, in effect, mandate that a small to medium.sized chemical plant
be erected at Site for treatment of the sludges and soils. Emissions
would be monitored, but some odor from such a facility is likely to
occur. However, EPA has determined that Alternative #5 be kept as a
contingency remedy if the field scale treatability study for
Alternative #4 does not meet the performance standards.
9.0
S~Y OF SELECTED 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 source control and groundwater monitoring remedy for
this Site. At the completion of this remedy, the risk associated with
this Site has been calculated at 1x10-6 which is determined to be .
protective of human health and the environment. The total present
worth cost of the selected remedy, Alternative #4, is estimated at
$9,900,000. .
A.
SOURCE CONTROL
Source control remediation will address the contaminated soils
and sludges at the Site. The area of contamination (AOC) at this
Sitecons"ists of the Hercules property commonly known. as the 009
Landfill, including all of the landfilled sludge cells, the
staging area located near the landfilled sludge cells, plus the
length of the drainage ditch where the ditch is adjacent to the
Hercules property, the soil on the banks of the drainage ditch,
the Benedict Road/Nix Lane area which abuts the-Hercules
property, and contiguous soils located just southeast of the
Benedict Road/Nix Lane area. Source control shall include
excavation of subsurface soils, sludges and related material in
the fo~er sludge staging area to 76 ppm of toxaphene, excavatio~
of the surface soils in the staging area and the Nix Road area to
0.25 ppm, transportation of these soils and sludges to the
landfill area, mixing of these soils and sludges with the
landfilled sludge, in-situ stabilization of the landfilled sludge
as well as stabilization of the soils from the staging area and
the Nix Road area, construction of a clay cover over the treated
50
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soiis to ~educe rainwater infiltration and direct contact.with
the treated soils and sludges, and back filling the excavated
areas back up to the original grade. Following source control
remediation, deed restrictions, which limit excavation on the
Hercules property, will be placed on the Site.
Since this is a innovative use of stabilization on organic
contamination, a field-scale treatability study must be conducted
early in the remedial design process. If, in ~PA's sole
discretion, the field-scale treatability study does not indicate
that stabilization of the contaminated soils and sludges will
achieve the performance standards in paragraph A.3, Alternative
#5, chemical extraction, will be used to remediate the Site. The
soils in the sludge staging area and the Nix Road area will still
be excavated; however, the landfilled sludge will also be
excavated. This material will be dewatered and treated by
chemical extraction. The treated soils and sluages will be
backfilled into the excavated areas. .
A.l. The ma;or components of source control to be
implemented include:
Based on the comparative analysis summarized in Table 8-1, EPA's
preferred cleanup alternative for the Hercules Site is
Alternative 4, treatment of affected surface soil and sludge in
place by in-situ stabilization. This alternative includes:
.
Conducting a field-scale treatability study and
implementation of in-situ stabilization of subsurface soils
and consolidated surface soils as an innovative application
of this technology since EPA has minimal information on
stabilization of manufactured pesticides;
.
If the treatability study concerning tha stabilization of
Site soils and sludges fails to meet the required
performance standards as set forth in paragraph A.3 and
therefore will not be effective if implemented, then
implementation of an onsite ex-situ chemical extraction
technology on the soils and sludges at the Site (with onsite
disposal of the treated material) would occur. This
represents Alternative 5 in the ROD.
.
For in-situ stabilization, construction of a cover over the
treated soils to reduce rainwater infiltration and eliminate
direct contact with the treated soil. This cover will meet
pertinent RCRA standards. In addition, areas excavated for
consolidation of surface soil will be graded and covered
with clean, compacted, .native fill and brought back up to
the original grade. Figure 9-1 indicates (by shading) the
major areas to be treated. The landfill cells will be
treated in place while the sludge-staging area and the
Benedict Road/Nix Road area will be excavated and
51
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consolidated into the landfill cells;
.
Institutional controls, such as deed restrictions, will be
established to preclude any extensive excavation of the Site
once the soils remedy is implemented; .
.
Operation and maintenance of the cover for a minimum of
thirty years; and
Air emissions from the Site will be monitored to ensure
compliance with the Clean Air Act. Air monitoring will be
conducted to ensure that contaminant concentrations do not
exceed levels considered to be safe for human health. If
levels are exceeded, mitigative procedures such as dust
suppression or vapor capture will be employed t.o prevent
harmful levels of air emissions from leavi~g the Site.
The selected alternative for the Hercules site is consistent with
the requirements of Section 121 of CERCLA and the National
Contingency Plan. The selected alternative will reduce the
mobility, toxicity, and volume of contaminated soil at the Site.
In addi~ion, the selected alternative is protective of human
health and the environment, will attain all Federal and State
applicable or relevant and appropriate requirements, is
cost-effective and utilizes permanent solutions-fo the maximum
extent practicable. The selected alternative for OU #1 is
consistent with previous remedial actions conducted at the Site
for OU #2. .
.
Based on the information available at this time, the selected
alternative represents the best balance among the. criteria used
to evaluate remedies. Alternative #4 is believed to be
protective of human health and the environment, will attain
AP~~s, will be cost effective, and will utilize permanent
solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable.
The cost of this alternative is $9,900,000. This alternative
will be fully protective of human health and the environment and
will meet all Federal and State requirements.
A.2. Treatment of in-situ and consolidated material
Alternative 4 consists of the treatment of affected surface soil
and sludge in place by in~situ stabilization. This alternative
involves the stabilization of subsurface soil, sludge and
consolidated surface soil, followed by the installation of a
multimedia cover. The conceptual layout of this alternative is
shown on Figure 9-1.
The surface soil remedial action target concentrations were used
to determine the excavation locations .and boundaries for surface
52
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soil. The subsurface soil target concentrations were used to
establish vertical and horizontal treatment boundaries for
subsurface soil and wastes. A sampling program will be conducted
to determine the actual volumes of surface soil and subsurface
soil requiring remedial action.
In this alt~rnative, subsurface solids and consolidated surface
soil will be treated in place within the landfill. A multimedia
cover will be placed over the consolidated, s~abilized soil to
reduce rainwater infiltration and direct contact with the treated
soil. In addition, areas excavated for consolidation of surface
soil will be" graded and covered with clean, compacted, native
fill. Treatment boundaries will approximate the appropriate
remedial action boundaries shown on Figure 9-1.
The incremental risk after implementation of this treatment
option shall be at least 1.0 x 10-6 for carcinogenic effects and
0.0003 for the hazard index for a child residing near the Site.
Both are within accepted EPA guidelines for risk exposure.
This option includes the use of deep soil mixing equipment that
delivers stabilization reagents to the affected solids during
mixing operations. The process involves augering into the
affected solids to the desired depth using hollow-stem augers.
The hollow-stem augers overlap and can vary frofu- two to five
augers per assembly. A shallow soil mixing system is also
available and uses a single, wide diameter auger rather than an
assembly of overlapping augers. Treatment reagents are injected
into the disturbed matrix through jets constructed in the auger
blades. The reagents can be injected in either a dry, liquid, or
slurry form. A system such as this could consist of the
following typical unit operations:
.
Shallow Soil Mixing Assembly
.
Reagent Containers and Feed Systems
Drilling depths are limited, but depths up to 30 feet are
reportedly attainable. The specific type of mixing/augering
system will be determined during remedial design. Treatment
duration will vary by depth and by the amount of mixing required
to ensure adequate stabilization. Treatability'studies will be
necessary during the remedial design phase to select the optimal
reagent composition and form. Testing of the solidified
treatment zones will also be necessary to ensure that performance
requirements are being met. Solidification/stabilization on
manufactured pesticides represents an innovative application of
this technology since EPA has minimal information on
stabilization of manufactured pesticides. The NCP encourages the
use of innovative technologies at Superfund Sites. For this
reason, and because this application may be effective at the
Site, solidification/stabilization treatment will be evaluated
53
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during the treatability studies for these waste. If the
stabilization process is unsuccessful, alternative #5 (Ex-Situ
Chemical Extraction) will be used to treat these wastes.However,
implementation of an onsite ex-situ chemical extraction
technology on the soi:s and sludges at the Site (with onsite
disposal of the treated material) will occur if the treatability
study concerning the stabilization of Site soils and sludges
fails to meet the required standards and therefore will not be
effective if implemented.
A.3. Performance Standards for Soils
The Performance Standards for this component of the selected
remedy include the following excavation and treatment standards:
a.
Excavation Standards
Contaminated soils, sludges and related materials shall be
excavated from the area of contamination, particularly the
sludge staging areas and the Benedict Road/Nix Lane area,
and transported to the Hercules 009 landfill for treatment.
Excavation shall continue until the remaining soil and
material achj~ve the following maximum toxaphene
concentration levels. Testing methods approved by EPA shall
be used to determine if the maximum allowafile toxaphene
concentration levels have been achieved, as follows:
Medium
Surface Soils
Subsurface Soils
Performance Goal
0.25 ppm
76 ppm
b.
Treatment Standards
Since the solidification/stabilization technology is not a
proven treatment technology for organics, treatment
effectiveness will be assessed using the TCLP, Multiple
Extraction Procedure and Total Waste Analysis (TWA) methods
for the manufactured pesticides at the Site. The stabilized
soils from this Site must achieve all of the following four
requirements for the technology to be considered effective.
1 .
The boiling point of the contaminants to be stabilized
must be higher than the boiling point of water. During
the stabilization process provisions must be made to
ensure that none of the contaminants volatilize. The
temperature of the process should not exceed 130
degrees F. .
2 .
The TCLP leachate from stabilized/solidified soils
would be required to, at a minimum, yield a leachate
that does not exceed Maximum Contaminant Levels (MCLs)
for the contaminants of concern at the Site.
55
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3 .
4.
5-
TWA will be utilized and compared to the original
analysis of waste using the same extraction procedures.
A 90 percent reduction in concentration or mobility of
the contaminated soil after treatment is the treatment
target. However, the 90 percent reduction in
contaminant concentration or mobility is a general
guidance and may be varied within a reasonable range
considering the effectiveness of the technology and the
clean-up goals for the Site. Although this policy
represents EPA's strong belief that TWA should be used
to demonstrate effectiveness of immobilization,
successf~l achievement of other leachability tests may
also be required in addition to TWA to evaluate the
protectiveness of the treatment. .
In addition, the solidification/stabilization mixture
is required to achieve a minimum of 50 psi compressive
strength and must demonstrate a permeability of lxlO-6
or less. A professional engineer must certify the
soils of the Site have sufficient strength to
structurally support the stabilized mass.
The rate bf disintegration for the stabilization
mixture must be determined and that rate be acceptable
to EPA. .
Soil requiring treatment which do not comply with these
standards will be excavated and treated by chemical
extraction. During the early stages of the preliminary
Remedial Design, the treatment standards will be used to
determine the effectiveness of the stabilization technology.
c.
Capping Standards
Recovered and condensed hazardous substances shall be
treated and disposed of in a manner to be determined in the
Remedial Design Phase and approved by EPA. Treatment and
disposal shall comply with all pertinent applicable or
relevant and appropriate requirements (ARARs), including,
but not limited to RCRA and TSCA.
B.
GROUNDWATER MONITORING/RESTORATION
Groundwater monitoring will be implemented at this Site to assess
any movement of contamination through groundwater. If toxaphene
begins to migrate off the Hercules property, if the other
contaminants of concern are shown to be 'migrating from their
current positions, if any levels of the contaminants of concern
begin to increase over fifty percent of their current value, or
in case it becomes apparent that onsite levels of contaminants in
the groundwater will not naturally attenuate below MCLs over
time, a contingency pump and treat system will be implemented.
56
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B.1. The ma;or components of qroundwater monitorinq/restoration
to be implemented include:
.
Long-term monitoring of groundwater, as well as surface
water and sediment in the onsite pond and the adjacent
drainage ditch, with the contingency implementation of a
pump and treat system in case any of the following occurs:
- toxaphene begins to migrate off the Hercules property; if
the other contaminants of concern are shown to be migrating
from their current positions; if any levels of the
contaminants of concern begin to increase over fifty percent
o~ their current value; or in case it becomes apparent that
onsite levels of contaminants in the groundwater will not
naturally attenuate below MCLs over time. The decision to
implement a pump and treat system will be at the sole
discretion of EPA. Measurable attenuation must be achieved
within 5 years after the completion of the-soil remedy for
the final operable unit for this Site or a pump a~d treat
system will be implemented. During Remedial Design interim
goals will be devised for groundwater contaminant levels
which indicate at what levels natural attenuation would be
expected to reach. Such interim-goals will be established
for annual intervals.' If two consecutive interim goals are
not met, a groundwater pump and treat system must be
initiated. The groundwater will be pumped-eo the surface
and treated onsite with granular activated carbon. The
spent granular activated carbon will be sent to a hazardous
waste facility for disposal as necessary. Thetreated
groundwater will either be discharged off-site to a local
publicly-owned treatment works, discharged onsite to the
onsite pond, or discharged off-site via an NPDES permit.
The ultimate fate of the treated groundwater will be
determined during the design of the pump and treat system.
If MCLs are met for two consecutive annual monitoring
p~riods (either by natural attenuation or pump and treat),
groundwater sampling may be discontinued at the discretion
of EPA;
.
Institutional controls, such as deed restrictions, will be
established to preclude usage of groundwater and minimize
land use until cleanup levels are achieved;
.
Proper abandonment of private wells which were replaced by a
municipal water source in OU#2 if the owners are amenable.
B.2. Extraction, Treatment, and Discharqe of Contaminated-
Groundwater
If deemed necessary by EPA, the groundwater will be pumped to the
surface and treated onsite with granular activated carbon or
other treatment. The spent granular activated carbon will be
sent to an appropriate hazardous waste facility for disposal as
57
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needed. The treated groundwater will be discharged to a local
publicly-owned treatment works. If a discharge permit cannot be
obtained, an NPDES permit for discharge to an off~site surface
water body will be obtained. If an NPDES permit for discharge to
an off-site surface water body cannot be obtained, onsite
discharge to the onsite pond will be considered as an
alternative. .
B.3. Performance Standards for Groundwater
a.
Treatment Standards
- .
If the following standards are not met by riatural
attenuation, groundwater shall be treated until the
following maximum concentration lev~ls are attained
wells to be designated by EPA as compliance points.
at the
Benzene
Nickel
Toxaphene
0.005 mg/l
0.1 mg/l
0.003 mg/l.
c.
Discharge Standards
Discharges from the groundwater treatment system shall
comply with all substantive requirements of-the NPDES
permitting program .under the Clean Water Act, 33 U.S.C.
.1251 et~., and all effluent limits established by EPA.
d.
Design Standards
The design, construction and operation of any groundwater
treatment system shall be conducted in accordance with all
Performance Standards, including the RCRA requirements set
forth in 40 C.F.R. Part 264 (Subpart F) .
C.
Compliance Testinq
Groundwater, treated soils, and surface water monitoring shall
be conducted at this Site. After demonstration of compliance
with all Performance Standards, the Site (including soil and
groundwater) shall be monitored for at least five years. If
groundwater and soil monitoring indicates that the Performance
Standards set forth in Paragraph B.3 are being exceeded at any
time after monitoring and/or pumping has been discontinued,
extraction and treatment of the groundwater will recommence
until the Performance Standards are once again achieved. If
monitoring of the treated soil indicates Performance Standards
set forth in paragraph A.3 have been exceeded, the effectiveness
of the source control component will be re-evaluated.
58
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10.0
STATUTORY DETERMINATION
Under CERCLA section 121, EPA must select remedies that are protective
of human health and the environment, comply with applicable or
relevant and appropriate requirements (unless a statutory waiver is
justified), are cost effective, and utilize permanent solutions and
alternative treatment technologies or resource recovery technologies
to the maximum extent practicable. In addition, CERCLA includes a
preference for remedies that employ treatment that permanently and
significantly reduce the volume, toxicity, or mobility of hazardous
wastes as their principal element. The following. sections discuss how
the select~d remedy meets these statutory requirements.
10.1
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy protects human health and the environment through
isolating and treating a principal threat by in-sitD stabilization of
the sludges and soils at the Site. If in-situ stabilization is shown
not to be effective through a field-scale treatability study to be
conducted, implementation of an onsite chemical extraction remedy will
occur. The minimum level of overall protection provided by in-situ
stabilizati~n is 1.0 x 10-6 for the lifetime excess cancer risk and
.0.0003 for the hazard index. The additional protection offered by in-
situ stabilization/ solidification is further enhanced by the short-
term protectiveness gained from treatment without excavation of waste
materials. Chemical extraction treatment will also provide overall
protection of human health.and the environment. Source excavation and
treatment will minimize the potential for future migration of waste
constituents to human receptors and the environment in and around the
009 Landfill Site. Long-term exposure from direct contact with, and
inhalation of, affected soil and dusts will be minimized by treatment
of all affected soil and sludge. This alternative would reduce the
incremental risk posed by direct contact to 1.0 x 10-6. The hazard
index would be less than or equal to 0.0003 for any specific
constituent, because the removal target levels of the sludge and
affected soil limits risk to these values. The selected remedy
provides protection of human health and the environment by
eliminating, reducing, and controlling risk through treatment,
engineering controls and/or institutional controls.
Groundwater monitoring will be implemented to ensure that no exposure
through ingestion of contaminated groundwater occurs; Currently only a
single contaminant in three separate sampling locations are above MCLs
at the Site. Therefore, no active remediation is to be immediately
implemented for groundwater. However, if contamination in the
groundwater. does not attenuate to below MCLs, the MCLs would be the
performance standard, and an active pump and treat system will be
implemented.
59
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10.2
ATTAINMENT OF THE APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs)
Remedial actions performed under CERCLA must comply with all
applicable or relevant and appropriate requirements (ARARs). All
alternatives considered for the Hercules site were evaluated on the
basis of the degree .to which they complied with these requirements.
The selected remedy was found to meet or exceed the following ARARs.
Clean Air Act
Air emissiQns from the remedial activities at the Site, including
thermal treatment, will be monitored to ensure compIiance with the
substantive requirements of the Clean Air Act. Air monitoring will be
conducted to ensure that contaminant concentrations do. not. exceed
levels considered to be safe for human health. If levels are
exceeded, mitigative procedures such as dust suppression or vapor
capture will be employed to prevent harmful levels of air emissions
from leaving the Site.
Chemical-Specific ARARs
Maximum Contaminant Levels (MCLs) and non-zero MCLGs (where each is
available) are the Groundwater Protection Standards set out in Table
6-2 of this ROD as the remedial action goals. If ie-becomes apparent
that MCLs will not be met due to attenuation, a contingency pump and
treat system will be implemented to insure that MCLs/MCLGs are met.
Action-Specific ARARs
All pertinent RCRA standards will be incorporated into the design and
implementation of this remedy. The RGRA Land Disposal Restrictions
(LDRs) are potential ARARs for remedial actions on the sludge and soil
at the 009 Landfill Site. The LDRs are applicable to remedial actions
that involve "placement" of restricted RCRA hazardous waste. Land
disposal restrictions are not applicable where banned waste is moved,
graded, stabilized, or treated in-situ, entirely within the original
area of contamination, because placement has not occurred, but may be
relevant and appropriate. Toxicity Characteristic Leaching Procedure
(TCLP) results indicated toxaphene was below detection limits in the
waste extract. The Hercules wastewater sludge generated from the
production of toxaphene is exempt from listing as a hazardous wastes
under RCRA (40 CFR 261) because the sludge was last handled in June
1980. Although not applicable, pertinent aspects of RCRA closure
requirements may be relevant and appropriate because a hybrid-landfill
closure system will be used unless the contingent remedy, chemical
extraction, is utilized. If the contingent remedy is utilized, then
RCRA closure requirements may be applicable. If a pump and treat
systems becomes necessary, all pertinent National Pretreatment
Standards will be met before either off-site or onsite discharge of
treated groundwater.
60
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Location-Specific ARARs
Both floodplain and wetlands considerations will be incorporated into
the design and implementation of this remedy.
Endanqered Species Act
The recommended remedial alternative is protective of species listed
as endangered or threatened under the Endangered Species Act.
Requirements of the Interagency Section 7 Consultation Process, 50 CFR
Part 402, will be met. The Department of the Interior, Fish &
Wildlife Service; will be consulted during remedial design to assure
that endangered or threatened species are not adversely impacted by
implementation of this remedy.
Waivers
Section 121 (d) (4) (C) of CERCLA provides that an ARAR may be waived
when compliance with an ARAR is technically impracticable from an
engineering perspective. No waivers will be invoked at this Site.
Other Guidance To Be Considered
Other Guidance To Be Considered-(TBCs) include health based advisories
and guidance. TBCs have been utilized in estimating-incremental
cancer risk numbers for remedial activities at the sites. The risk
data is evaluated relative to the normally accepted point of departure
risk range of 1x10-4 to 1x10-6.
10.3
COST EFFECTIVENESS
EPA believes this remedy will eliminate the risks to human health at
an estimated cost of $9,900,000; therefore, the selected remedy
provides an overall effectiveness proportionate to its costs, such
that it represents a reasonable value for the money that will be
spent.
10.4
UTILIZATION OF PERMANENT SOLUTIONS TO THE MAXIMUM
EXTENT PRACTICABLE
EPA and the State of Georgia have determined that the selected remedy
- represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective manner for
the final source control operable unit at the Hercules 009 Landfill
Site. Of those alternatives that are proteGtive of human health and
the environment and comply with ARARs, EPA and the State have
determined that this selected remedy provides the best balance of
trade-offs in terms of long-term effectiveness, and permanence,
reduction in toxicity, mobility or volume achieved through treatment,
short-term effectiveness, implementability, cost, while also
considering the- statutory preference for treatment as a principal
element and conside~ing state and community acceptance.
61
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10.5
PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
By treating the contaminated soils and sludges by stabilization, the
selected remedy addresses one of the principal threats posed by the
Site through the use of treatment technologies. By utilizing.
treatment as a s;~nificant portion of the remedy, the statutory
preference for remedies that employ treatment as a principal element
is satisfied.
. 11.0
DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for the Hercules 009 Landfill Site was released for
public comment in August, 1992. The Proposed Plan identified
Alternative 4, in-situ stabilization, as the preferred alternative.
EPA reviewed all written and verbal comments submitted during the
public comment period. Upon review of these comments, it was
determined that no significant changes to the remcjy, as it was
originally identified in the Proposed Plan, were necessary.
62
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APPENDIX A:
RESPONSIVENESS SOHMARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
ISSUE
1.
Alternative 5, chemical
extraction, should be the
chosen remedy instead of
EPA'.s preferred remedy of
stabilization.
BPA RESPONSB
Alternative 4, stabilization,
meets all 9 evaluation
criteria and provides the
best balance among all
alternatives. Since the
method of treatment, .
stabilization of organics, is
an innovative technology,
Alternative 4 also meets the
agency's preference for the
use of an innovat~ve
technology. P.Jwever, since
this use of technology is
innovative in this situation,
EPA is proposing alternative
5, chemical extraction as a
contingency remedy.
2 .
In depth health studies
are required to determine
impact of contaminants on
. communi ty .
Under CERCLA, the._purpose of
the RIfFS is to gather enough
information to make a remedy
selection .decision which is
protective of human health
and the enviro~~ent. The
possible impact of
contaminants on a community
in the past is not necessary
in determining how to reduce
risks in the future. Health
concerns must be addressed by
the Agency for Toxic
Substances and Disease
Registry (ATSDR).
63
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RESPONSIVENESS SOMMARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
ISSUE
BPA RESPONSB
3.
Stabilization is an
unproven technology for
organic contamination that
is not suitable for this
site and contamination
would remain a threat to
the c_ommuni ty .
The agency promotes the use
of innovative technologies at
Superfund sites. Abench-
scale treatability study
using -
solidification/stabilization
was conducted for this Site.
This treatability study
indicates that stabilization
is suitable for this Site,
and is protective of human
health and the environment..
Stabilization, while yet
unproven at this Site, has
been used at several sites
with organic contamination,
including the Solidtech, .
Alaska Refinery, and Velsicol
Chemical Sites.
4.
The bentonite liner will
be destroyed during in-
situ stabilization.
5.
Any drilling or auguring
in the landfill during in-
situ stabilization or
chemical extraction could
release air-borne
contaminants.
Once the sludge is
stabilization, the
liner will have no
value.
Air monitoring will be
conducting during any field
activities during remedial
design and remedial action.
Precautions will be taken to
minimize any air-borne
releases. The Health and
Safety Plan for the Remedial
Action will further address
what steps will be taken to
minimize air releases as well
as what steps will be taken
in the event of a substantial
release.
treated by
bentonite
further
64
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RESPONSIVENESS SOHNARY - BBRCOLBS 009 LANDF:ILL,
RECORD OF DBC:ISION
:ISSUE
BPA RESPONSB
.6.
What is rationale for
disturbing the sludge and
liner if the cells are not
leaking?
7 .
The contingency of
chemical extraction would
expose the community to
contamination due to
excavation, leaks from
mechanical equipment
during treatment and there
still will be residual
toxaphene present in the
remaining soil. .
Contamination is currently
being found outside of the
cells in the staging area in
both the soils and
groundwater. The staging
area is immediately adjacent
'to the soutnernmost cell and
is in the direction of
groundwater flow from the
landfill cells. Whether this
contamination is coming from
the sludge cells is
uncertain; however, the
potential threat exists that
the cells could leak in the
future.
If the treatability study
which is to be conducted
using stabilization indicates
that stabilization is not
appropriate, the execution of
a chemical extraction remedy
would cause a moderately-
sized chemical treatment
facility to be placed on the
Site. Air monitoring would
be conducted to detect any
potential leaks from the
mechanical equipment required
for a chemical extraction
remedy. The machinery would
be replaced as needed. The
cleanup goals of 76 ppm for
subsurface soils and 0.25 ppm
for surface soils will be met
by the ei ther the.
stabilization remedy or the
contingency chemical
extraction remedy.
65
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RESPONSIVENESS SOMMARY - HERCULES 009 LANDFILL,
RECORD OF DBCISION
ISStJB
BPA RESPONSB
8.
Alternative 3,
installation of a-RCRA
cap, is the only
alternative that provijes
for adequate risk .
protection from potential
futu~e contamination with
minimal threat during
remedial action.
9 .
Alternative 5, chemical
extraction, is the only
pe~nent remedy.
Alternative 3, 4, and 5 all
provide adequate risk
protection. Stabilization,
alternative #4, is protective
of human health and the
environment, provides for
adequate risk protection from
potential future -
contamination, and has
minimal threat during
remedial action since this
treatment will be- done in-
situ.
Both Alternative 4,
(stabilization) and
Alternative 5 (chemical
extraction) are permanent
remedies.
10.
A cancer impact study
concerning carcinogens
within the landfill is
needed due to the increase
in cancer rates in the
local corranunity.
The corranunity and-the Glynn
County Heaith Department have
asked ATSDR to look at health
issues that could be related
to this Site. ATSDR will
advise EPA and the corranunity
of their findings.
66
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RESPONSIVBNBSS SUHHARY - IIBRCOLBS 009 LANDFILL,
RECORD OF DECISION
11.
ISStJB
The RI fails to address
the following risks .and
requires further study and
sampl ing.:
1) Risk to children at
Altama Elementary School
2) Exposure to residents
on Benedict road to
surface contaminants.
3) Risk to employees at
Nalley Auto Sales
4) Risk to general
population due to spillage
from trucks hauling the
toxaphene wastes from
Hercules to the landfill.
EPA RESPONSE
Sampling will be done during
the Remedial Design and
Remedial Action stages of
this project ~o further
delineate the extent of
contamination. However, such
sampling would not affect the
remedy selection decision for
this Site. 1) The Baseline
risk assessment evaluates
onsite risks and did not
include an exposure scenario
for a school being placed
.onsite. However, the risk
assessment. did include an
exposure assessment for a
future onsite resident
family, which includes
children living on the
landfill for 365 days per
year for 24 hours a day. The
onsite resident exposure
scenario is more conservative
than a future onsite school
scenario. The risk
assessment is used to
establish Site-specific
health-based cleanup goals.
2) The exposure of. residents
on Benedict Road/Nix Lane to
surface contaminants is
addressed by the conservatism
of the health-based cleanup
goals generated from the
future-onsite residential
scenario. The 6.2 ppm level
of toxaphene found-in the
front yard of adjacent
residents is higher than the
health-based cleanup goal for
the Site; therefore, the
surface soil contamination
will be delineated and
removed from the residential
areas. Due to the
contamination. found in the
resident's yards, a referral
67
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RESPONSIVBNBSS SOHHARY - HERCULES 009 LANDFILL,
. . RECORD OF DECISION
ISSUE
EPA RESPONSE
12.
Why was sampling location
SD-4 near Altama
Elementary not sampled in
1990 and 1991, the only
location not tested for
toxaphene.
Removal Branch of EPA was
made. However, this 6.2 ppm
level of toxaphene does not
constitute an immediate
danger; and therefore did not
meet the requirements for an
immediate removal action.
The conservative risk
assessment factors in a 70-
year lifetime of exposure)
when establishing cleanup
goals, which is not
considered in determining
whether an immediate threat
exists. 3) The surface soil
contamination is generally
located in the staging area
near the southeastern corner
of the landfill away from the
Nalley Auto Sales~-acility.
Rainwater runoff from the
staging area drains towards
the drainage ditch to the
east and the onsite pond to
the south. However, further
sampling will be conducted
north of the landfill in the
area of the auto sales
facility. 4) The RI is not
intended to address risks
from the Hercules processing
plant to the Site.
SD-4 was sampled in 1990 for
the full Target Compound and
Target Analyte Lists (which
include toxaphene), No
contaminant detections were
found. Since no detections
were noted in 1990, this
location was not resampled in
1991, but more sampling
locations were added further
away from the Site and in the
onsite pond.
68
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RESPONSrlBNBSS SUMMARY - HERCULES 009 LANDPILL,
RECORD OP DECISION
13.
ISSUB
A complete and thorough
tes'ting plan is needed to
assure children at the
school are not exposed to
contaminants.
14.
The drainage ditch needs
to be included in the
clean up and the area
around the school
remediated back to
background levels at a
mini~um.
EPA RESPONSE
In response to public
concern, the area of the
school adjacent to the
drainage ditch was sampled in
February, 1993. - EPA will
evaluate the results of that
sampling effort and provide
the results to the school
board.
The Baseline Risk Assessment
indicates that the drainage
ditch does not pose a
significant risk to human
health and the environment. .
The area around the school
was tested in February, 1993,
and if any contaminants were
detected, the results will be
referred to the Emergency
Response and Removal Branch
of EPA as well as to ATSDR.
As a matter of risk
evaluation, EPA uses a
Baseline Risk Assessment to
determine cleanup standards
in the 1.0x10-6 to 1.0x10-4
excessive cancer risk range
remediating to background
levels is generally not
practical or feasible. EPA
has determined that this
target risk range is
protective of health and
environment.
69
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RESPONSIVBNBSS SOMHARY - HERCULES 009 LANDF:ILL,
RECORD OP DEC:IS:ION
:ISSUB
15.
Health riskQ to residents
from Benedict Road/Nix
Lane have been ignored. .
Immediate steps should be
taken to stop exposure to
these residents.
BPA RESPONSE
The 6.2 ppm level of
. toxaphene found in the front
yard of adjacent residents is
higher than the health-based
cleanup goal for-the Site;
therefore, the surface soil
contamination will be .
delineated and removed from
the residential areas. The
6.2 ppm level of toxaphene
found in the front yard of
adjacent residents was the
basis for a referral to the
Emergency Response and
Removal Branch of EPA. This
level of toxaphene was found
not to constitute an
immediate danger, and
therefore did not meet the
requirements for an immediate
removal action. The risk
assessment utilizes a
conservative 70-year lifetime
of exposure when establishing
cleanup goals. Action levels
for immediate removal actions
do not take into
consideration a lifetime
exposure but rather short-
term acute exposures. During
the Remedial Design/Remedial
Action phases of this
project, further sampling and
soil excavation will occur
along the Benedict Road/Nix
Lane area.
70
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RESPONSIVENESS SOHMARY - HERCULES. 009 LANDPILL,
RECORD OP DECISION
ISStrB
EPA RESPONSE
16.
Conclusions and
recommendations from
ATSDR's November 1988
Preliminary Health
Assessment have been
ignored and delayed.
17.
Benedict Road/Nix Lane
testing is insufficient to
determine the full extent
of contamination, both
horizontally and
vertically. A
comprehensive testing plan
is required.
The conclusions in ATSDR's
Preliminary Health Assessment
(PHA) were neither ignored
nor delayed. The PHA states
that further environmental
characterization and sampling
of the Site and impacted off-
site areas should-occur
during the RI/FS. Such
actions were undertaken. The
PHA further states that when
additional information and
data became ava~lable, e.g.,
the completed RI/FS, such. .
material will form the basis
.for further assessment by
ATSDR at a later date. The
sampling conducted during the
RI/FS was methodical.
Sampling centered.-around the
landfill and then moved
outward to off-site areas.
The RI report has been
forwarded to AT$DR.
More testing in the Benedict
Road/Nix Lane area will occur
during the Remedial Design
and Remedial Action Stages of
this project.
71
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RESPONSIVENESS SOMHARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
ISSUE
18.
A comprehensive testing
plan is needed f~omthe
point(s) trucks were
loaded along the route(s)
to the landfill to address
contamination along the
transportation route.
BPA RESPONSB
This Site was listed on the
National Priorities List
based upon a release at the
landfill. The purpose of the
RIfFS was to colLect enough
information to make a remedy
selection decision which
would reduce the threat posed
by the landfill. More
testing in the Benedict
Road/Nix Lane area will occur
'during the Remedi~l Design
and Remedial Action Stages of
this project to determine the
extent of contamination
related to releases from the
Site.
19.
There appears to be no
mention of the flood plain
or the one-hundred year
flood plan in the RI.
20.
The environmental
assessment is very biased
and is not a scientific
study; therefore, no
conclusions can be made on
long: term effects of the
site on the environment.
The RI report does not
mention the flood_plain, but
this issue will be addressed
during the Remedial Design
and Remedial Action stages of
this project. '
The environmental assessment
was designed to evaluate
representative species which
would frequent the Site to
determine what the risks
would be to such species.
Moreover, biota from the
drainage ditch were collected
and analyzed for toxaphene.
The risks to the ecological
species are less than the
risks to any potential onsite
resident. Since tne risk
assessment for human health
was used to establish cleanup
goals, these goals are more
stringent than the cleanup
values generated by the
ecological risk assessment.
Thus the proposed remedy is
protective of human health
and the environment.
72
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RESPONSIVENESS StJMNARy - HBRCULBS 009 LANDPILL,
RECORD OP DECISION
ISSOB
EPA RESPONSE
21.
Has in-situ stabilization
been used at similar
sites?
22.
Sampling results near the
school were missing from
the RI result sections.
23.
What is toxaphene? Is it
the only chemical at the
site?
Yes, in-situ stabilization
has been used at dozens of
sites. Stabilization, while
it is innovative at this
Site, has been used at
several sites which contain
organic and/or pesticide
contamination incYuding
Solidtech and Velsicol
Chemical.
The ftNature and Extent of
Contamination a section
. (Chapter 3) of the RI report
contains a discussion of the
results of the 1990 sampling
in the drainage ditch near
the school. The complete
analytical results are listed
in the appendix oL-the RI
report. .
Toxaphene was an. agricultural
pesticide. Toxaphene
received widespread use in
the southeastern United
States to control boll
weevils on cotton as well as
mites and ticks on cattle,
until EPA banned its use in
1982. Other chemicals such
as acetone, carbon
tetrachloride, chlorobenzene,
chloroform, and xylenes were
detected in the landfilled
sludge samples.
73
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RESPONSIVENESS SOHNARY - HERCULES 009 LANDPILL,
RECORD OP DECISION
24.
ISSUE
How was the landfill
constructed? .
BPA RESPONSE
The landfill was operated
from 1975 to 1980. One.
percent toxaphene sludge by
weight was transported from
Hercules' plant fn Brunswick
to the Site. The sludge was
placed in six separate cells.
The cells are linea with a
bentonite/stump dirt liner.
Some drums and rubble are
believed to have been placed
in the first cell~ The cells
measure 100 by 200 feet in
size, and are approximately
six feet deep.
25.
How much sampling was done
at the site? Is the
extent of contamination
known?
28 surfac~ soil samples, 27
subsurface soil borings, and
18 monitoring wells have been
investigated as part of the
RI. Methodical sampling of
surface soil, subsurface
soil, sediment, surface
water, groundwater, and air
was conducted at the site.
More work is necessary to
det~rmine the full extent of
the toxaphene contamination,
which will be conducted
during Remedial Design.
74
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RESPONSIVENESS SOHHARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
26.
ISSUB
What does the RI say about
the clay liner? will it
hold and stop the movement
of Toxaphene?
BPA RESPONSB
The liner for the cells has
been in place for at least 12
years and appears to be an
effective barrier at this
time. Toxaphene-was
engineered to bind strongly
to soils, so its movement is
limited. Much of the
surficial contamination at
the Site is linked to the
sludge staging area. "
However, the selected remedy
will permanently immobilize
the toxaphene, thus reducing
the need for the clay liner.
For more information, the
complete R~ Report is
available for public review
at the Glynn County Library
at 208 Gloucester ~treet in
Brunswick.
27.
What does the RI say about
underground water flow at
the site?
28.
The site is often mowed.
Does this pose a threat?
Groundwater flows to the
southeast at the Site at
seepage velocities of
approximately 60 to 90 feet
per year. For more
information, the complete RI
Report is available for
public review at the Glynn
County Library at 208
Gloucester Street in
Brunswi ck ".
No, the Site is mowed to
prevent any growth of large
vegetation. If any
vegetation such as. shrubs or
trees grew on the landfill,
strong winds or tornadoes
could uproot the trees and
act to bring the sludge to
the surface. "
29.
Does the site pose a
threat to the environment?
Yes. If left untreated, the
Site could pose a threat to
both human health and the
environment.
75
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RESPONSIVBNBSS StJMHARY - HERCULES 009 LANDFILL,
RECORD OF DECISION
30.
ISSUE
Has the site affected
birds, raccoons and deer
populations which are now
rare in this area?
31.
What do chemical
measurements really mean
(i.e. ppb)?
EPA RESPONSE
There is not evidence that
the Site has affected
wildlife. The scarcity of
wildlife in the area is
probably not due-to this
Site, but instead due to the
greatly increased
urbanization of the area in
recent years.
PPB is the abbreviation for
"parts per billion". If a'
chemical is measured
analytically to exist in a
sample at a level of 1 part
per billion, that means that
the ratio of that substance
in that sample is one
molecule of that substance
for every billion~lecules
that are present in this
sample.
32.
Is bioremediation a
possibility?
33.
Whqt has testing indicated
about Altama Elementary
School?
Bioremediation is possible at
pesticide sites, but the
levels found in the landfill
and the slow kinetics of
biological reduction of
pesticides in general make
bioremediation a poor choice
of remediation for this Site.
A sample collected in the
drainage ditch adjacent to
the school did not contain
any contaminants. More
sampling of the school area
adjacent to the drainage
ditch was conducted,in
February 1993. EPA will
eval~ate the results of that
sampling efforts and provide'
the results to the school
board.
76
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RESPONS:IVBNBSS StJHKAJly - BBRCtJLBS 009 LANDP:ILL,
RECORD OF DBC:IS:ION
:ISSUE
BPA RESPONSB
34.
How are action levels set?
For surface soils, action
levels were set at this Site
by conducting a Baseline Risk
Assessment. By assuming no
remediation was done and that
a family with children lived
on top of the landfill (which
would be a worst-case
scenario for exposure),
levels were calculated that
would not cause auy cancer
risks greater than a one-in-
a-million chance that one of
the future scenario residents
would get cancer due to any
exposure from this Site. For
subsurface soils, action
levels are determined by
calculating what level of
contamination could remain
and still be protective of
groundwater in the subsurface
soils. For groundwater the
action level is the Maximum
Contaminant Level (MCL) , as
determined under the Safe
Drinking Water Act.
77
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RESPONSIVENESS SOHMARY - IIBJlCULBS 009 LANDFILL,
RECORD OF DECISION
35.
ISStJB
What are the health.
effects of Toxaphene?
Can toxaphene cause birth
defects?
EPA RESPONSE
Generally, toxaphene exposure
for long periods can result
in damage to the liver,
kidneys, lungs, and nervous
system. According to the
ATSDR's Toxicoloqical Profile
for Toxaphene, no _information
on the reproductive effects
of toxaphene in humans is
available; however,. studies
exist which indicate a low
potential to induce adverse
reproductive affects in lab
animals. For more. complete
information, please refer to
the Toxicoloqical Profile for
Toxaphene which is available
in the repository at 208
Gloucester Street in
Brunswick. .
36.
Are health problems
occurring in the
community? Does the RI
address community health?
37.
What was the Site
permitted for?
A number of health problems
that have occurred in the
Brunswick community were
raised at the public meeting
held September, 1992.
However, the RI does not
address community health
because the RI is designed to
study the Site to establish
enough information to select
a remedy to reduce risk posed
by contamlnation at the Site.
The Site was permitted by the
State of Georgia for the
disposal of 1% toxaphene
sludge from Hercules' main
processing facility in
Brunswick.
38.
Where may I get a copy of
the permit?
Under the Freedom of
Information Act, a letter may
be sent to the GaEPD
requesting this information.
78
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RESPONSIVENESS SOHHARY - BBRCt7LBS 009 LANDFILL,
RECORD OF DBCISION
ISSUE
BPA RESPONSB
39.
Who was involved in the
permitting of the Site?
40.
Was there any type of
testing done during the
period the sludge was
being' landfilled?
The Georgia Environmental
Protection Division and
Hercules were involved in the
permitting process.
Landfilling of sludge was an
aqceptable practice when the
009 landfill was p~rmitted.
EPA does not have testing
information concerning this
Site prior to 1980.
Monitoring of the-Iandfilling
operations was overseen by
the State of Georgia.
41.
Were the carbon
tetrachloride and' other
chemicals present when the
landfilling operations,
were in operation? If so,
at what levels?
42.
Was the Site permitted for
the dumping of drums,
pallets, glassware, etc.?
EPA does not have any records
of any tests conducted during
landfilling operations.
Therefore, it is unknown if
carbon tetrachloride and
other chemicals were present
when landfilling occurred.
However, carbon tetrachloride
has been detected from the
sludge samples collected
during the RI. Carbon
tetrachloride and other
chemicals may have been
present when the toxaphene
sludge was landfilled.
However, breakdown products
of the tox~phene sludge could
also account for some of the
chemicals of concern. Carbon
tetrachloride has been
detected in the landfill
sludge at 4.0 ppm..
Permit #063-003D(SL)H allowed
for the disposal of incoming
toxaphene -wastes. Drums,
pallets, and glassware are
not specifically mentioned in
the permit. The landfilling
of rubbish was discontinued
after the initial cell was
closed.
79
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RESPONSI:VBNBSS SOHKARY - BBRCULBS009 LANDPI:LLr
RECORD OP DBCI:SI:ON
I:SStJB
BPA RESPONSB
43.
What was in the drums and
glassware that were
landfilled?
44.
What plans have been made
to address the toxaphene
contamination along
Benedic't Road/Nix Lane?
The drums and glassware are
believed to have been empty;
however, residues from their
original content_s may have
been present. The drums and
glassware are believed to
have contained the raw
materials which were used at
the Hercules plant to
manufacture toxaphene.
Further testing ~illbe done
during remedial design along
the Benedict Road/Nix Lane
area. Any areas of
contamination above action
levels will be excavated and
placed on the landfill.
45.
Does the toxaphene
contamination found along
Benedict Road/Nix Lane
pose a threat to the
children who live in this
area?
The toxaphene fouQQ along the
Benedict Road/Nix Lane area
poses a potential threat to
the health of the children in
the area. Therefore, during
the Remedial Design/Remedial
Action phases of this
project, further sampling and
soil excavation will occur
along the Benedict Road/Nix
Lane area to eliminate this
potential threat. Based on
the conservative risk
assessment, the 6.2 ppm'level
of toxaphene found in the
front yard of adjacent
residents exists as an
additional cancer risk over a
70-year lifetime of exposure.
However, this level of .
toxaphene does not constitute
an immediate danger and
therefore did not meet the
requirements for an immediate
removal action.
80
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RESPONSIVENESS SUHHARY - HERCULBS 009 LANDPILL,
RECORD OP DBCISION
46.
ISSUE
Did the contractors that
installed the waterlines
along Benedict Road/Nix
Lane bring high levels of
toxaphene to the surface?
BPA RESPONSB
Probably not. High levels of
toxaphene are not believed to
exist along Benedict Road/Nix
Lane. Limited s~pling was
conducted during the water
.line installation. This
sampling did not ~ndicate any
high levels of toxaphene in
the area. Further testing
will be conducted during the
Remedial Design/Remedial
Action phases of this project
to fully delineate the
contamination.
47.
If contaminants of concern
such~s carbon
tetrachloride, benzene,
xylene, etc.~ go into the
water table, would the
private wells off-site be
impacted?
The potential exists for off-
site wells to be impacted
whenever organic compounds
are released to the water
table. At this S~e however,
the off-site wells
immediately downgradient of
the landfill have been
sampled since 1985, and have
always been shown not to
contain organics above the
practical quantification
limits.
48.
Why were air samples not
taken during landfilling
operations?
The landfill was created
using the best available
practices at the time.
Air sampling was not a common
practice when the landfilling
operations were occurring.
81
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RESPONS:IVBNBSS StJHHARY - BBRCtJLES 009 LANDP:ILL,
RECORD OF DECISION
.49.
:ISSt7B
Is it harmful to breathe
toxaphene?
50.
If there is no danger in
drinking water from the
private wells along
Benedict Road/Nix Lane,
why would Hercules agree
to pay $129,000 to run
. water lines?
.EPA RESPONSE
Since toxaphene is a
potential human carcinogen,
inhalation of toxaphene could
potentially be h~rmful.
Generally, toxaphene exposure
for long periods can result
in damage to the liver,
kidneys, lungs, ana nervous
system. For more complete
information, please refer to
the Toxicoloqical Profile for
Toxaphene which is available
in the repository at 208
Gloucester Street in
Brunswick.
Any substantive response by
EPA regarding Hercules'
motives would be entirely
speculative. Repr~sentatives
of Hercules are best able to
knowledgeably respond.
51.
52.
When the landfill cells
were being constructed,
what was done with the
water in the borrow pit?
Will toxaphene cause DNA
mutation in humans?
53.
Were two Remedial
Investigations conducted
at the Site?
EPA does not have any records
of what was done with the
water in the borrow pit.
Data indicates that toxaphene
is a mutagen. For more
complete information, please
refer to the Toxicoloqical
Profile for Toxaphene which
is available in the
repository at 208 Gloucester
Street in Brunswick.
No, only one Remedial
Investigation was conducted.
The RI did, however, go
through several phases as is
generally the case with
remedial studies.
82
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RESPONSIVBNBSS SOHHARY - HERCULBS 009 LANDFILL,
. RECORD OF DECISION
54.
ISSUE
Why did it ~ake so long to
run the water lines and
hook-up the residents?
55.
If any of the chemicals
reported were present in
the well water at higher
than or just below EPA
permitted levels, how long
could a person drink this
water before they may show
health problems?
EPA RESPONSE
Approximately 3 months were
necessary to negotiate the
agreement with Hercules to
install the lines;
approximately six months were
needed to write, review, and
approve the work plans and
designs; approximately 6 .
months were needed to obtain
the proper permits, and
approximately 6 months were
needed to get ac~ess from all
residents.
The Maximum Contaminant
Levels (MCLs) are calculated
based upon an excess cancer
risk in the range of 1. Ox 10-4
to 1.0x10-6 which is
calculated over a~~ year
lifetime. However, any
chemical sensitivities which
vary greatly by individual
may influence one's tolerance
toward any given chemical.
56.
Would EPA recommend that
the people that live on
Benedict Road/Nix Lane
move from where they live
because of the Site?
No,.EPA has no data to
indicate such a
recommendation is warranted.
83
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RESPONSIVENESS SOHHARY - HERCULES 009 LANDP:ILL,
RECORD OF DECIS:ION
57.
ISSUE
Where did the benzene and
'dioxins corne from? .
EPA RESPONSE
Neither can be definitely
traced to a specific source.
Dioxin is found in minute
levels across tQe Site and in
background samples. The
landfilling operations might
not be the source_of the
dioxins. The incineration of
chlorinated hydrocarbons in
the vicinity of the Site may
potentially be the source of
the dioxins. Potential
sources of the benzene could
be either a breakdown product
of the chemicals in the
landfill or could be due to a
leaking underground storage
tank which contains petroleum
products.
58.
Why was the Nix Road area
not tested before 1992?
59.
What were the sample
results from the GaEPD
testing of the water and
soil in March of 1980?
The National Priority Listing
is for the 009 Landfill. The
RI/FS investigation and study
began at the landfill and
worked outward. More
investigation and delineation
along the Benedict Road/Nix
Road area will occur during
the Remedial Design and
Remedial Action stages of
this project.
Testing of the drainage ditch
adjacent to the Site
indicated a level of 435 ppm
of toxaphene in the ditch, .
which is why the l~ndfilling
permit was revoked. The
exact location of this sample
is not currently known.
After closure of the
landfill, monitoring wells
began to be installed from
1980 to the present.
84
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RBSPONSZVBNBSS SOMNARY - HERCULES 009 LANDFILL,
RECORD OF DECISION
60.
ISStJB
Why did EPA place the Site
on the NPL in 1984?
61.
Why did EPA wait u~til
1987 to take over the
Site?
EPA RESPONSE
The Hazard Scoring System for
the National Priority List
takes into account several
factors. The primary reason
for ranking this Site was the
actual release (documented by
the State) to the ~rainage
ditch, and the potential
threat to private wells
nearby.
EPA did not take over the
Site. The Georgia
Environmental Protection
Division relinquished the
lead from this Site in 1987
due to a lack of resources.
62.
Private wells were not
sampled until 1985.
Landfilling operations
began in 1975. Would the
concentration levels of
carbon tetrachloride,
benzene, xylene, etc.,
have been higher in. the
nearby wells when the
landfill operations were
ongoing than the levels
are now?
It is possible that levels
would have been high~r when
operations were active.
However, if organics such as
benzene, xylene, or carbon
tetrachloride were in the
groundwater, residual amounts
would be detected in the
onsite and off-site wells.
Onsite wells were installed
in 1983.
85
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RESPONSIVENESS StJMHARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
ISSt7B
63.
Where were the nickel and
benzene levels above MCLs?
In what medium were they
detected?
BPA RESPONSB
They were detected in
groundwater. To date,
monitoring well N-6SR (in the
former staging area) has
indicated toxaphene
contamination at a level of
0.069 ppm (the MCL is 0.003
ppm), well N-5 and KV-5
indicate benzene at levels of
0.13 ppm and 0.011 ppm
respectively (the MCL for
benzene is 0.005 ppm), and
KV-3 indicates nickel
contamination at a level of
0.186 ppm (the MCL for nickel
is 0.1 ppm). See Figure 5-1
in the RI Report for
monitoring well locations.
64.
What are the contaminants
. at the Site other than
toxaphene?
65.
Can EPAorder a health
study be done instead of
the community being
required to initiate the
health study?
The contaminants GE concern
are listed in table 6-1 and
6-2 in this ROD, but only
toxaphene was found above
cleanup goals.
No, health studies must be
initiated by someone in the
community. A health study
has been requested from ATSDR
by the community and that
agency is taking action upon
this request.
86
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RESPONS:IVENBSS SOMHARY - HERCULBS 009 LANDPILL,
RECORD OF DBCISION
66.
ISSOB .
Would it be better to
remove the toxaphene
chemically (Alternative
#5) to .be sure no further
remediation will be
necessary? It is cheaper
in the long run to do the
job right the first time.
67.
Would disturbing the
landfill material as
proposed in Alternatives 4
and 5 do more harm than
good?
BPA RESPONSB
Because it is better to do
the job correctly the first
time, and in order to insure
that Alternative-#4 will do
the job right, a field-scale
treatability study will. be
conducted. The stabilization
treatment will be designed to
permanently bind the
chemicals. If field-scale
treatability stud~es indicate
that stabilization will not
permanently bind a sufficient
percentage of the
contamination, then
Alternative #5 will be
implemented as a contingency
remedy.
No. The potentiar-exists for
the landfill to fail and
release contamination to the
environment in the future.
Treatment of the material
now, before failure, is
necessary to protect human
health and the environment.
68.
Would incineration be a
better choice of treatment
for the sludge at this
Site?
No. Incineration is a viable
technology for treatment of
the sludge. However, the
urban area around the Site
would not be conducive to.
incineration activities.
69.
70.
Has Hercules received any
fines or penalties for
polluting the Site?
Why was toxaphene banned?
No fines or penalties have
been assessed by E?A.
Toxaphene was found to be a
potential human carcinogen
and was banned to insure
protection of human health.
87
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RESPONSIVENESS SOHKARY - HBRCtJLBS 009 LANDFILL,
RECORD OF DBCISION
ISS0'2
BPA RESPONSB
71.
Why is a cleanup action
being proposed if the
landfill is not leaking?
72.
Would the acidic
groundwater conditions
reduce the life expectancy
of concrete in an in-situ
stabilization remedy?
The potential exists for the
landfill to fail and release
contamination to the
environment in ~e future.
Treatment of the material
now, before failure, is
necessary to protect human
health and the environment.
A field-scale treatability
study will be conducted
specifically to answer this
question. During this
treatability study, the
affect of acidity and other
environmental conditions such
as freeze and thaw cycles
will be investigated.
73.
Would Alternative #4,
stabilization, actually
inhibit self-cleansing of
the Site by encapsulating
the waste?
Encapsulation iSR8t expected
to hinder the natural
degradation of the chemicals
of concern at the Site.
However, stabilization
differs from solidification
in that stabilization is
designed to chemically bind
the chemicals of concern
rather than simply
encapsulating them
(solidification). The
stabilization treatment at
this Site will be designed to
chemically bind a large
percentage of the
contamination.
88
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RESPONSIVENESS StJMHARy - HERCULBS 009 LANDFILL,
. RECORD OF DBCISION
ISSUE
BPA RESPONSB
74.
Was in-situ treatment of
the toxaphene sludge using
potassium hydroxide
considered?
75.
Will underestimations of
soil yolume affect final
cleanup costs?
The use of potassium
hydroxide is not specifically
mentioned. However, an in-
situ precipitation (chemical
stabilization) treatment
which consists of dosing the
contaminated material with an
aqueous reagent to form
insoluble compounds in the
soil matrix was evaluated but
screened out since these
technologies are generally
effective for metals
immobilization only.
Underestimations of soil
volume could affect final
cleanup. costs; however, best
efforts have been used to
determine the soiJ:- -volume and
to estimate cleanup costs.
89
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RESPONSIVENESS SOHKARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
76.
:ISSUE
The RI only considered
chemical transport through
the groundwater by laminar
flow although potential
movement may occur by
"lens-effects".
:SPA RESPONSB
It appears that this comment
was made concerning possible
sedimentary structures that
are lenticular in shape that
may have slightly higher
permeabilities than
surrounding materials
resulting in preferential
flow paths. Data has not
been presented that such
features exist at this Site.
However, if they did exist"
the hydraulic effects of any
such small scale sedimentary
structures would be averaged
out at the scale of the Site.
Where these structures might
cause a local diversion from
laminar flow by a few inches,
at the scale of the Site in
" tens of feet, these local
effects cancel each other out
and laminar flow adequately
represents the subsurface
hydraulics of the Site. If
such features did exist,
their impacts would not be
significant at the scale of
this Site.
77.
The criteria of "overall
protection of human health
and the environment" must
be given greater weight in
considering options for
"remediation than "cost".
Correct. "Overall protection
of human health and the
environment" and "attainment
of ARARs" are the two
threshold criteria for making
a remedy selection decision.
Remedies that do not meet
these two criteria are not
considered further. "Cost"
is a balancing criteria.
Stabilization meets the
criteria of overall
protection of human health
and the environment by
reducing the risk posed at
this Site to less than
1.0 x 10-6.
90
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RESPONS:IVBNBSS SOHHARY - HERCULES 009 LANDF:ILL,
RECORD OF DEC:IS:ION
:ISSUE
EPA RESPONSE
78.
The propo~~d remedy for
the Site is excessively
conservative. The risk
reduction for containment
by a RCRA cap (Alternative
#3) is equivalent to
stabilization (Alternative
#4) .
79.
The exposure scenarios
used for this Site are not
reasonable due to deed
restrictions which
. currently are imposed o~
this Site. The
assumptions and
methodologies required by
EPA significantly
overstate actual risks
posed at the Site.
The risk reduction for
containment is similar to
that of stabilization;
however, the additional
criteria of reducing
toxicity, mobility and volume
through treatment is not met
by capping. Moreover, EPA
has strong preference for
permanent and innovative
treatment, and the
stabilization o~ organics is
an innovative treatment and
permanent solution. Capping,
on the other hand, would not
treat the landfill at all,
only contain it.
EPA has a policy of using the
future onsite resi~ential
scenario on all sites unless
the site is in a heavily
industrialized area with no
residences nearby. The
assumptions and methodologies
required by EPA are intended'
to err, if they must, on the
conservative side in order to
protect human health and the
environment.
80.
81.
The full economic impact
of this Site on the
Brunswick area is not
clear. A clearer
understanding of the
economic impacts is
needed.
Since action levels are
not based on an
understanding of
toxaphene's effect on the
general population a more
conservative estimate is
needed to ensure the
public health.
Economic impact is not a
factor for selecting
Superfund remedial cleanup.
In fact, the action levels
are based .on an understanding
of toxaphene's effect on the
general population.
Moreover, the action levels
are conservative.
91
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RESPONSIVENESS SUMNARY - HERCULES 009 LANDPILL,
RECORD OF DECISION
ISSUE
BPA RESPONSB
82.
The reporting of results
is inaccurate. Two soil
borings (SB-30, SB-31) are
mentioned in the text.
The text states that
toxaphene was detected in
SB-3G, although neither
sampling event is shown on
maps of soil borings or in
the summary discussion of .
the soil borings.
Stabilization of organics
is an innovative
(experimental) treatment
technology. This .
community .is not the place
to conduct an experiment.
83.
84.
Has the Site been tested
for dioxin?
EPA regrets the omission of
these two soil borings on the
map. These two borings were
drilled through ~he landfill
cells. However, this.
oversight does not impact the
sampling results and remedy
selection for this Si~e.
Both stabiliz~tion of
organics and chemical
extraction are considered
innovative. Stabilization of
organics has been used at
more Superfund sites than
chemical extraction. The
only technology fGF this Site
which would not be considered
innovative is incineration.
An area which is quickly
undergoing urbanization would
not be amenable to an
incinerator. The treatment
which would cause the least
disturbance and release. of
organics into the atmosphere
is in-situ stabilization.
Yes, the Site has been tested
for dioxin. Dioxin has "been
detected in the landfilled
sludge at levels up to
3 . 9x1 0-4 ppm. For more
information, please refer
chapter 3 of the RI Report.
85.
Is there any danger from
the landfill in attending
the Altama Elementary
School?
No, EPA has no data to
indicate there is any danger
to the school from the
Landfill. However, Hercules
sampled the schoolyard in
February 1993. EPA and ATSDR
will evaluate those results
and provide them to the
school board.
92
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RESPONSIVENESS SOHHARY - BBRCt7LBS 009 LANDFILL,
RECORD OF DECISION
86.
ISSt1B
Is this Site ahead of Love
Canal on the NPL?
87.
Has the municipal water in
the school been tested
during the RI?
BPA RESPONSE
Yes, this Site was listed as
#153 on the list in 1990
while Love Canal was listed.
as #158. All sites on the
NPL are treated the same once
they are listed. Also, the
numerical listing is not a .
true indicator of the
severity of the site, but
rather indicates how well the
site meets the listing
criteria.
No, any monitoring of
municipal water would be
conducted by the county and
regulated by GaEPD.
88.
What is the time frame for
remediation to occur? Can
delays possibly allow more
contamination to escape
from the landfill cells?
89.
Why was the Site not
sampled in a grid-like
fashion?
Negotiation and lodging of a
Consent Decree between EPA
and Hercules may take up to a
year. Remedial Design
generally takes 1.5 years.
The Remedial Action phase may
take 2 years. Monitoring
will continue to protect
human health and the
environment during this time.
Because the landfilling
operations were conducted
recently and the operations
history of the Site was well
known.
90.
Has toxaphene ever been
reported in the off-site
private wells? At what
levels? Did the levels
increase with time?
Yes. Toxaphene was found in
a.quantity below the
practical quantification
limits of the instrumentation
and is not fully
differentiated from matrix
interferences on the
chromatograph. Toxaphene has
not been found to increase
with time in the groundwater
at this Site.
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RESPONSIVENESS SUMNARY - HERCULES 009 LANDFILL,
RECORD OF DECISION
ISStJB
EPA RESPONSE
91.
Is the contamination
moving outward from the
Site faster than the
testing is being done?
What is the degradation
rate of toxaphene?
92.
93 .
Is there any way to tell
if toxaphene will migrate
from the monolith after
stabllization occurs?
No. Toxaphene was engineered
to bind tightly to soils and
is relatively immobile.
No site-specific degradation
rates have been measured.
However, according to the
ATSDR's Toxicoloqical Profile
for Toxaphene, a study
indicates that toxaphene has
a half-life of 11-years in a
sandy soil.
Yes. The planned
"treataoility study will be
designed to answer this
question. In addition, soil
monitoring will occur
periodically afte~_the
monolith is in place.
94.
If chemical extraction is
implemented, what will be
done with the extracted
toxaphene?
95.
How much consideration has
been given to urban
encroachment in the
Feasibility Study?
Why did the RI take so
long?
96.
This will be determined
during the Remedial Design
stage of the project if
chemical extraction is
implemented.
In the FS, urbanization was a
factor in attempting to gauge
community acceptance of a
remedy such as incineration.
Turnovers in personnel at
EPA,changes in personnel and
environmental consultants
with Hercules, and the
necessity of additjonal
phases of field work are the
reasons the RI took longer to
satisfactorily complete.
94
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RESPONSIVENESS SUMMARY - HERCULBS 009 LANDFILL,
RECORD OF DBCISION
97.
ISSUE
Could the acidic
groundwater conditions
tend to cause toxaphene to
form a dense, nonaqueous
phase liquid (DNAPL)?
98.
Is there any way to be
sure that all of the
sludge will be mixed with
the cement slurry during
stabilization?
BPA RESPONSB
Toxaphene is denser than
water, and in the presence of
a sufficient quantity of a
carrier solvent, could become
a major component of a DNAPL.
However, no indications of a
DNAPL have been found at this
Site.
The treatability. study will
be designed to help answer
this question. The augering
and mixing process will
involve large hollow-stem
augers going all the way to
the bottom of the cells.
Typically, overlapping augers
are used to mix the material
to ensure complete
homogenization.
99.
Why were isopleths of
groundwater contamination
not shown in the RI
report?
100
Since the extent of
contamination is not
known, how do you know
that areas will not be
missed during remediation?
Isopleths of groundwater
contamination were not shown
in the RI report since only
three single, differing,
contaminants were found in
three separate wells. An
isopleth surrounding a single
data point would be
meaningless.
Further sampling will occur
outward from the Site during
the Remedial Design phase of
this project to ensure no
areas of contamination
connected with the Site are
overlooked.
101
Can the dredging of the
ditch be banned?
The dredging is apparently
necessary to drain the mall
parking area sufficiently.
Any ban on the dredging of
this ditch would have to be
mandated by the City of
Brunswick.
95
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RESPONSIVENESS SOMMARY - HERCULES 009 LANDPIL~,
RECORD OP DECISION
102
ISSUE
Can the reported dumping
of toxaphene from.
Hercules' main processing
plant in Brunswick into
Terry Creek be
investigated?
EPA RESPONSE
Yes, this activity is
currently being investigated
by EPA.
103
When -sampling the
residential wells, why was
the tap allowed to run for
approximately 15 minutes
before a sample was
collected?
The standard protocol for
sampling (as listed in EPA
Region IV's Environmental
Compliance Branch Standard
Operatinq Procedures and
Oualitv Assurance Manual is
to purge the well before
sampling so that a true
sample of groundwater quality
is obtained instead of a
sample which may be affected
by the plumbing.
96
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APPENDIX B
CONCURRENCE LETTER - HERCULES 009 LANDFILL
RECORD OF DECISION
97
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FROM:DNREPD ADMIN MGT
DNREPD ADM I N MGT ~
TO: 404 347 3058 MAR 24, 1993 4:10PM P.01
Georgia Department of Natural Resources
205 Butler Street. S.E.. Suite 1252, Atlanta. Georgia 30334
Joe D. Tanner. COmmissioner
Harold F. Roheis. Director
Environmental Prolection Division
March 23. 1993
Mr. Richard Green
Associate Division Director
Office of Superfund
U.S. EPA. Region IV
345 Courtland Street. N.E.
Atlanta, Georgia 30365
RE:
Record of DeCision
. Hercules 009 NPL Site
Dear Mr. Green:
The Georgia Environmental Protection Division (EPD) has reviewed the Record of
Decision, Summary of Remedial Alternative Selection, Operable Unit One for the Hercules 009
Landfill NPL sire. EPD concurs wit.h the selected remedy. .
1f you have any questions, please contacl Mr. Michael Laney at (404) 656-2833.
HFRlmlb
c.: Alan W. Yarbrough
file: Hercules 009(B)
f:\usCl\dr.adte~nIli::8'McuJes.11t
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