EPA Superfund
Record of Decision:
PB99-964007
EPA541-R99-025
1999
Marzone Inc/Chevron
Chemical Co. Site OU2
Tifton, GA
7/1/1999
-------
-------
RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
MARZONE INC./CHEVRON CHEMICAL COMPANY SUPERFUND SITE
OPERABLE UNIT TWO
TIFT COUNTY, GEORGIA
PREPARED BY
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION 4
ATLANTA, GEORGIA
-------
-------
TABLE OF CONTENTS
1.0 SITE LOCATION AND DESCRIPTION 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 1
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 3
4.0 SCOPE AND ROLE OF OPERABLE UNITS 4
5.0 SUMMARY OF SITE CHARACTERISTICS 5
5.1 PHYSIOGRAPHY/TOPOGRAPHY 5
5.2 GEOLOGY/SOILS 5
5.3 SURFACE WATER AND SEDIMENTS . .- 6
5.4 HYDROGEOLOGY 6
5.5 SAMPLING STRATEGY 7
6.0 SUMMARY OF OPERABLE UNIT TWO RISKS 23
6.1 HUMAN HEALTH RISK ASSESSMENT 25
6.1.1 CONTAMINANTS OF CONCERN 25
6.1.2 EXPOSURE ASSESSMENT 25
6.2 ECOLOGICAL RISK ,' 33
6.2.1 ECOLOGICAL SETTING 33
6.2.2 EXPOSURE ASSESSMENT 39
6.2.3 THREATENED AND ENDANGERED SPECIES REVIEW .40
6.3 REMEDIATION OBJECTIVES 44
7.0 DESCRIPTION OF ALTERNATIVES 46
7.1 SOIL AND SEDIMENT ALTERNATIVES 47
7.1.1 ALTERNATIVE NO. 1 - NO FURTHER ACTION 47
7.1.2 ALTERNATIVE NO. 2 A/B - EXCAVATION AND SOLIDIFICATION/
STABILIZATION WITH ONSITE DISPOSAL 47
7.1.3 ALTERNATIVE NO. 3 A/B - EXCAVATION AND OFFSITE
DISPOSAL 48
7.2 GROUNDWATER ALTERNATIVES 49
7.2.1 ALTERNATIVE NO. 1 - NO ACTION ALTERNATIVE 49
7.2.2 ALTERNATIVE NO. 2 - MONITORED NATURAL ATTENUATION
49
7.2.3 ALTERNATIVE NO. 3 - FUNNEL AND GATE 50
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES 51
8.1 OVERALL PROTECTION OF HUMAN HEALTH AND THE
ENVIRONMENT : 52
-------
8.2 COMPLIANCE WITH ARARS 53
8-3 LONG-TERM EFFECTIVENESS AND PERMANENCE 53
8-4 REDUCTION OF TOXICTTY. MOBILITY OR VOLUME TRROTTGW
TREATMENT " ~~
8.5 SHORT-TERM EFFECTIVENESS ' " .' 54
8.6 IMPLEMENTABILITY ,.,
8.7 COST ^
8.8 STATE ACCEPTANCE '.'.'.'"' "
8.9 COMMUNITY ACCEPTANCE '.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'. 55
9-0 SUMMARY OF SELECTED REMEDY ... 55
9.1 SOIL AND SEDIMENT REMEDY .' ." ' „
9.1.1 DESCRIPTION OF REMEDY .' 57
9.1.2 PERFORMANCE STANDARDS 5g
9.1.3 SOIL TESTING 5g
9.1.4 COST 5*
9.2 GROUNDWATER REMEDY ..'.'.'.[ JJ
9.2.1 DESCRIPTION OF REMEDY ... 59
9.2.2 PERFORMANCE STANDARDS . 61
9-2.3 GROUNDWATER TESTING .,
9.2.4 COST .'.'.'.'.'.'.'.'';.'.'.'.'.'.'.' ' " 62
10.0 STATUTORY DETERMINATION 62
l0-1 PROTECTION OF HUMAN HEALTH AND'THE'ENVIRONMENT '
10-2 ATTAINMENT OF THE APPLICABLE PR RELEVANT AND ^
APPROPRIATE REQUIREMENTS f AR ARC> M
10.3 COST EFFECTIVENESS *
10-4 UTILIZATION OF PERMANENT SOLIJTIDNSTo'THE MAYTMTivr
EXTENT PRACTICABLE 65
H.O DOCUMENTATION OF SIGNIFICANT CHANGES 66
-------
TABLES
TABLE 5-l:ORGANIC CONTAMINANTS IN SURFACE SOIL 8
TABLE 5-2:INORGANIC CONTAMINANTS IN.SURFACE SOIL 9
TABLE 5-3: ORGANIC CONTAMINANTS IN SUBSURFACE SOIL 10
TABLE 5-4: INORGANIC CONTAMINANTS IN SUBSURFACE SOIL . . 11
TABLE 5-5: CONTAMINANTS IN DITCH SURFACE WATERS 12
TABLE 5-6: CONTAMINANTS IN WETLAND SURFACE WATER 13
TABLE 5-7: CONTAMINANTS IN GUM CREEK SURFACE WATER 14
TABLE 5-8: CONTAMINANTS IN DITCH SEDIMENTS 15
TABLE 5-9: CONTAMINANTS IN WETLAND SEDIMENTS 17
TABLE 5-10: CONTAMINANTS IN GUM CREEK SEDIMENTS 18
TABLE 5-11: ORGANIC CONTAMINANTS IN GROUNDWATER - MARCH 1996 19
TABLE 5-12: ORGANIC CONTAMINANTS IN GROUNDWATER - MAY 1998 19
TABLE 5-13: ORGANIC CONTAMINANTS IN GROUNDWATER - DECEMBER 1998 . . 20
TABLE 5-14: INORGANIC CONTAMINANTS IN GROUNDWATER 21
.TABLE 5-15: INORGANIC CONTAMINANTS IN GROUNDWATER 22
TABLE 5-16: INORGANIC CONTAMINANTS IN GROUNDWATER 23
TABLE 6-1: CHEMICALS OF POTENTIAL CONCERN FOR HUMAN HEALTH 24
TABLE 6-2: SURFACE SOIL EXPOSURE POINT CONCENTRATIONS SUMMARY .... 26
TABLE 6-3: SURFACE WATER EXPOSURE POINT CONCENTRATION SUMMARY . . 27
TABLE 6-4: GROUNDWATER EXPOSURE POINT CONCENTRATION SUMMARY ... 28
TABLE 6-5: CANCER SLOPE FACTORS FOR CHEMICALS OF POTENTIAL
CONCERN 29
TABLE 6-6: REFERENCE DOSES FOR CHEMICALS OF POTENTIAL CONCERN 31
TABLE 6-7: RISK CHARACTERIZATION SUMMARY - CARCINOGENS - CURRENT
USE 34
TABLE 6-8: RISK CHARACTERIZATION SUMMARY - NON-CARCINOGENS -
CURRENT USE 35
TABLE 6-9: RISK CHARACTERIZATION SUMMARY - CARCINOGENS - FUTURE
USE 36
TABLE 6-10: RISK CHARACTERIZATION SUMMARY - NON-CARCINOGENS -
FUTURE USE 37
TABLE 6-11: SUMMARY OF CANCER AND NON-CANCER RISKS BY EXPOSURE ... 38
TABLE 6-12: SUMMARY OF CANCER RISKS BY EXPOSURE ROUTE -
FUTURE USE SCENARIO 38
TABLE 6-13: SUMMARY OF NON-CANCER RISKS BY EXPOSURE ROUTE -
FUTURE USE SCENARIO 39
TABLE 6-14: ECOLOGICAL EXPOSURE PATHWAYS OF CONCERN 42
TABLE 6-15: ECOLOGICAL ORGANIC CONTAMINANTS OF CONCERN 43
TABLE 6-16: SUMMARY OF SOIL AND SEDIMENT REMEDIATION PERFORMANCE
STANDARDS FOR CONTAMINANTS OF CONCERN 45
TABLE 6-17: SUMMARY OF GROUNDWATER REMEDIATION PERFORMANCE
STANDARDS FOR CONTAMINANTS OF CONCERN 46
-------
TABLE 7-1: OPERABLE UNIT #2 SOIL ALTERNATIVES 47 .-
TABLE 7-2: OPERABLE UNIT #2 GROUNDWATER ALTERNATIVES 49 IB'
TABLE 9-1: SUMMARY OF SOIL AND SEDIMENT REMEDIATION PERFORMANCE
STANDARDS FOR CHEMICALS OF CONCERN . 59
TABLE 9-2: SUMMARY OF GROUNDWATER REMEDIATION PERFORMANCE
STANDARDS FOR CHEMICALS OF CONCERN 61
TABLE 9-3 - SUMMARY OF SELECTED REMEDY COSTS 63
TABLE 9-3 -SUMMARY OF SELECTED REMEDY COSTS 64
TABLE 10-1: CONTAMINANT-SPECIFIC ARARS 67
TABLE 10-2: LOCATION-SPECIFIC ARARS ... 68
TABLE 10-3: POTENTIAL ACTION-SPECIFIC ARARS 71
TABLE 10-4: TO-BE-CONSIDERED (TBCs) DOCUMENTS1 '.'.'.'.'.'.'.'.'.'.'.'.'.'.'.12
FIGURES
FIGURE 1-1: SITE MAP 2
FIGURE 9-1: APPROXIMATE NON-WOODED WETLAND AREA OF '
CONTAMINATION 60
-------
The major components of the selected remedy for operable unit two include:
• Excavation and disposal of surface soils which exceed the surface soil performance
standards.
• Excavation and disposal of sediments from the railroad drainage ditch and from the non-
wooded wetland area south of the railroad spur which exceed the sediment performance
standards.
Transportation by truck of contaminated soil and sediment to a permitted Subtitle C or D
landfill.
• Restoration of surface soil and wetland areas.
Confirmation sampling to verify that remaining soil and sediment is below performance
standards.
Monitoring of wetland and creek area for at least five years to determine if remaining
contamination is naturally attenuating. Levels of contamination in these areas do not pose
an immediate or acute threat; therefore, access restriction is not necessary.
• Installation of at least two additional groundwater monitoring wells.
Annual groundwater monitoring for at least five years for the contaminants of concern, as
well as potential transformation products and geochemical parameters to determine if
comtaminanation is naturally attenuating.
Review of groundwater data after five years to determine if natural attenuation is effective.
A contingency remedy of an in-situ treatment wall system may be implemented at EPA's
sole discretion, if results do not confirm that natural attenuation is effective.
• Institutional controls to restrict use of contaminated groundwater.
The selected remedy will address the principal threat wastes of toxaphene and DDT and its
breakdown products, as well as secondary threat wastes of chlordane, BHCs, endrin, dinoseb, and
metals. Toxaphene, DDT, chlordane and metals are found in surface soils and sediments, posing
an unacceptable risk to human health and the environment. BHCs, endrin, dinoseb, and metals are
found in groundwater and pose an unacceptable risk to future users of groundwater as a drinking
water source.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with federal and
state requirements that are legally applicable or relevant and appropriate, and is cost-effective.
-------
-------
Although this remedy does not utilize treatment that reduces toxicity, mobility, or volume as a
principal element, this negative aspect is outweighed by the cost-effectiveness, long term
effectiveness and ease of implementing the selected remedy. Finally, it is determined that this
remedy utilizes a permanent solution and alternative treatment technology to the maximum extent
practicable.
ROD DATA CERTIFICATION CHECKLIST
The following information is included in the Decision Summary section of this Record of
Decision. Additional information can be found in the Administrative Record file for this site.
• Chemicals of concern (COCs) and their respective concentrations
• Baseline risk represented by the COCs
• Cleanup levels established for COCs and the basis for the levels
• Current and future land and groundwater use assumptions used in the baseline risk
assessment and ROD
• Land and groundwater use for which the site will be available as a result of the Selected
Remedy
Estimated capital, operation and maintenance (O&M), and total present worth costs;
discount rate; and the number of years over which the remedy cost estimates are projected
Decisive factors that led to selecting the remedy
Because this remedy will result in hazardous substances remaining onsite above health-based
levels that would allow for unlimited use and unrestricted exposure, a review will be conducted
every five years after commencement of the remedial action to ensure that the remedy continues
to provide adequate protection of human health and the environment.
RICHARD D. GREEN, DIRECTOR DATE
WASTE MANAGEMENT DIVISION
-------
o
-------
Decision Summary
Record of Decision
Operable Unit Two
Marzone Inc./Chevron Chemical Company
Tifton, Georgia
1.0 SITE LOCATION AND DESCRIPTION
The Marzone Inc./Chevron Chemical Company Site (hereinafter, "Marzone" or "the Site") is
located in south-central Georgia in the city of Tifton, at the intersection of Golden Road and the
Norfolk-Southern Railroad tracks (EPA ID# GAD991275686). The Site consists of two former
facilities where various liquid and dry formulations of pesticides and/or fertilizers were handled
for approximately thirty years. The current owner of the two properties is Milan, Incorporated.
This Record of Decision (ROD) addresses all environmental media (soil, surface water, sediment,
and groundwater) associated with Operable Unit 2 (OU2), roughly defined as the Golden Seed
property, Gum Creek and the associated wetlands, and a segment of the railroad drainage ditch
(see
Figure 1).
During the Remedial Investigation for OU1, pesticides and metals were discovered in the soils and
sediments in and around the Golden Seed facility, which is located approximately 1,000 feet
southeast of the former formulation facility at OU1. Because the Golden Seed facility served as a
separate source area, the Site was divided into two operable units. EPA conducted the Remedial
Investigation/Feasibility Study for OU2 of the Site.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
The Marzone OU2 Property may have been used as a formulation and packaging plant for
pesticides and fertilizers chemicals from the 1967 until 1992. It appears that the handling of
agricultural chemicals commenced at the Marzone OU2 property as early as 1967. Pesticide
formulation and/or fertilizer operations may have been conducted by a succession of owners until
1992 when business operations at the Marzone OU2 Property apparently ceased.
The Site was listed oh the National Priorities List (NPL) in August 1989. Chevron Chemical
Company, Kova Fertilizer, Inc., and Billy Mitchell, three of the Potentially Responsible Parties
(PRPs), agreed to conduct the Remedial Investigation/Feasibility Study (RI/FS) at what later
became OU1 pursuant to an Administrative Order By Consent dated September 1990. In the
course of the Remedial Investigation, sampling on the Golden Seed Property established that
significant source contamination existed on the Golden Seed Property.
EPA conducted a removal action at OU2 in 1993 to remove raw chemicals, contaminated debris,
and heavily contaminated surface soils. Containers of chemicals, including pesticides and
-------
i—\^—CITY WATER
Y\ SUPPLY WELL
FORMER
WOOD
TREATMENT
ANNEX
PROPERTY
FORMER SHED
HORSE PASTURE
FORMER BURN
PEANUT
DISTRIBUTION <3
FACILITY
^-prr AREA
GOLDEN
SEED
PROPERTY
OU BOUNDARY
EXISTING ROADWAY
EXISTING RAILROAD
DITCH CENTERUNE
CREEK
EXISTING BUILDING
375'
750'
Figure 1-1: Site Map
-------
herbicides were found at the site. EPA demolished and removed several on-site structures,
excavated and removed the first foot of soil in areas of contamination, and excavated and
removed contaminated subsurface soil and debris to an action level for subsurface soils of 10
ppm for total pesticides. Over 6,000 tons of soil and debris were removed and shipped to a
permitted landfill.
EPA issued a ROD for Operable Unit 1 on September 30,1994, which called for (1) low
temperature thermal desorption of contaminated soils and (2) pumping and treating of
contaminated groundwater. Chevron Chemical Company and Kova Fertilizer are conducting the
remedial design/remedial action (RD/RA) pursuant to a Unilateral Administrative Order (UAO).
The soil remedy was changed by a ROD amendment in July 1997 to off-site landfill disposal.
EPA has approved the installation of a full-scale pilot project for the groundwater remedy
utilizing an in-situ treatment wall. The in-situ treatment wall was installed in August 1998. EPA
will review the performance of the pilot project before evaluating whether a ROD amendment is
appropriate for the OU1 groundwater remedy.
EPA initiated the Remedial Investigation/Feasibility Study (RI/FS) for the Marzone OU2 property
in November 1995. Field work was conducted by EPA's contractor, CDM Federal Program
Corporation, and EPA's Environmental Response Team. A Remedial Investigation/Feasibility
report was issued by EPA in June 1998.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The Tifton and Tift County Public Library at 1 Library Lane was chosen as the local information
repository for the Site. Since the NPL listing of the Marzone Site in 1989, numerous public
meetings and open houses have been held regarding OU1. The public comment period for the
original OU1 ROD was from July 15, 1994 to September 14, 1994. A public meeting was held
on July 26,1994. A public comment period for the first proposed plan for a ROD amendment,
which covers the former burn pit area, was held from September 16,1996 to November 16, 1996
A public meeting was held on September 26, 1996. A second public comment period for the
former burn pit ROD amendment was from August 25, 1998 to September 25, 1998. A public
meeting was held on September 3, 1998. The former burn pit ROD amendment was issued on
November 10,1998. In addition, a 30-day public comment period was provided on an
Explanation of Significant Differences which was issued in September 1996. A public comment
period for the second proposed plan for a ROD amendment was held from April 1, 1997 to May
1,1997. A public meeting was held on April 17, 1997. The ROD amendment for OU1 was
signed on June 18, 1997. An Explanation of Significant Differences was issued in July 1998.
EPA met with members of the community in February 1998 to discuss the progress of the RI/FS
for OU2. The public comment period on the proposed plan for the OU2 ROD was July 31, 1998
through October 10,1998. A public meeting was held on September 3,1998 where
representatives for EPA answered questions regarding the Site and the proposed plan under
consideration. The administrative record was available to the public at both the information
3
-------
repository maintained at the Tifton/Tift County Public Library and at the EPA Region IV Library
at 61 Forsyth Street in Atlanta, Georgia. The notice of availability of these documents and of the
public comment period was published in the Tifton Gazette on July 31, 1998. Notice of an
extension to the comment period and rescheduled public meeting was published in the Tifton
Gazette on August 25,1998. Notice of an additional extension to the public comment period was
published on September 15, 1998. These notices were also published in the Tift Area Today
Calendar. Responses to the significant comments received during the public comment period and
at the public meeting are included in the Responsiveness Summary, which is part of this ROD.
EPA awarded a Technical Assistance Grant (TAG) to the community group, People Working for
People, Inc. (PWP), in April 1995. PWP utilized the grant through approximately May 1997 to
hire a technical advisor to provide technical expertise to the community. PWP is now using
technical services through EPA's Technical Outreach Services for Communities to provide
technical expertise to the community.
This decision document presents the selected remedial action for operable unit two of the
Marzone site, chosen in accordance with CERCLA, as amended, and the NCP. The decision for
this Site is based on the administrative record. The requirements under Section 117 of CERCLA
for public and state participation have been met for this operable unit.
4.0 SCOPE AND ROLE OF OPERABLE IJNTTS
The Marzone Site was divided into two operable units (OUs) after the RI field work discovered
an additional source area at the Golden Seed facility. Additional Potentially Responsible Parties
(PRPs) may be involved on OU2, since that property was, at times, owned and operated
separately from OU1. These units are generally as:
• OUOne: Contamination of the soils and groundwater at the former Marzone facility, a
portion of the Slack property, and a segment of the railroad drainage ditch from Golden Road to
the mid-point between the culverts located at the southern portion of the railroad spur. EPA
signed a ROD for this operable unit on September 30, 1994. OU1 addresses surface and
subsurface soil contamination from pesticides and other organic chemicals, as well as groundwater
contamination resulting from the soil contamination. The purpose of operable unit one is to
prevent current or future exposure to the contaminated soils by removing surface contamination,
to reduce contaminant migration into the groundwater by removing subsurface contamination
which served as a source to the groundwater, and to initiate groundwater restoration. This
operable unit for soils is in the remedial action phase. Soil excavation and disposal is complete.
For groundwater, this operable unit is in the remedial design phase. A foil-scale pilot
groundwater treatment system has been constructed and is operating. EPA will review the
performance of the pilot project before evaluating whether a ROD amendment is appropriate for
the groundwater remedy.
-------
• OU Two: Contamination of the soils and grouhdwater at the Golden Seed facility and
adjacent property to the west and north of the Golden Seed facility, as well as sediments and
surface water in Gum Creek, the associated wetlands, and the railroad drainage ditch from the
mid-point between the culverts located at the southern portion of the railroad spur to the
northeastern corner of the Golden Seed facility. Operable unit two addresses the source of
contamination at the Golden Seed facility and resulting soil, groundwater, surface water and
sediment contamination. The purpose of operable unit two is to reduce the principal threats from
pesticides, other organic chemicals, and metals which have contaminated surface and subsurface
soil and have migrated into the groundwater and sediments.
5.0 SUMMARY OF SITE CHARACTERISTICS
The conceptual model for Operable Unit Two involves drums and disposal pits as the primary
sources. Leaching from the pits and spills from the drums served as the primary release
mechanism into the soil. Secondary release mechanisms from the soil include dust and/or volatile
emissions which could be carried by wind to human and ecological receptors,
infiltration/percolation into the groundwater which could carry contaminants to human and
ecological receptors (Gum Creek and associated wetlands), and storm water runoff which could
carry contaminants by surface water or sediments to human or ecological receptors.
5.1 PHYSIOGRAPHY/rOPOGRAPHY
The city of Tifton is located in the south-central portion of the Tifton Upland subdivision of the
Coastal Plain Physiographic Province. The Tifton Upland is a topographically high section of the
Coastal Plain where ground surface elevations range upward to approximately 500 feet, National
Geodetic Vertical Datum of 1929 (NGVD). The regional land surface slopes downward toward
the southeastern border of the upland to approximately 100 feet NGVD.
Tift County consists of uplands, river terraces, and flood plains with moderately wide interstream
divides separating relatively broad valleys. The surface expression of the divides is generally
level, very gently sloping or undulating, while the valley walls have modest slopes and nearly level
valley floors.
5.2 GEOLOGY/SOILS
The Coastal Plain is composed of a wedge of clastic and carbonate sediments ranging in age from
Jurassic/Cretaceous to recent. The depth of the Coastal Plain sediments varies from a feather-
edge thickness at the Fall Line to more than 7,000 feet in southwestern Georgia. The sediments
represent both non-marine and marine sources. The Coastal Plain sediments lie unconformably on
a basement complex of Piedmont crystalline rocks, Triassic red beds and volcanics, and
metamorphosed Paleozoic sedimentary rocks.
-------
Extensive sedimentary deposition has occurred in the Site area. The two primary geologic units
of interest are the Hawthorne Group and the underlying Floridan Aquifer System, represented in
this area by the Suwannee Formation.
The uppermost geologic unit occurring in the study area is the Miocene-age Hawthorne Group
The Hawthorne has two major fades: a non-marine fades composed of the Coosawhatchiue
Formation, the Marks Head Formation and the Parachuchla Formation, and a marginal
manne/non-manne fades composed of the Altamaha Formation. The Hawthorne Group occurs at
ground surface in the study area and extends to an approximate depth of 300 feet below grade at
1™J^T J^~?L3i!? ?°!northwest of *• former Marzone facility (OU1). The Hawthorne is
composed of interbedded clay and clay with limestone, with minor beds of sand, sandy clay sand-
silt and clay, and limestone. 3i
The Hawthorne is reported to be continuous throughout the study area. In the Site area, the
^^^Ca&aa^ 3°° ?*• The H*™110™ G«»P » significant to the Site because it is
CtiriNlnfirf*n trt nA a fvmfinintr unit* nTrAf*Nn**s> +1*^ T71M« J _ A •*+ *i .
n i/unmung unit, overlying tne Flondan Aquifer System, a major water
The Hawthorne Group is underlain by the Oligocene-age Suwannee Formation. The Suwannee
occurs at a depth of 300 or more feet below grade in the study area. It is composed of monolithic
hmestone which is locally cavernous. The Suwannee represents the Floridan Aquifer System in
S^S^Kr^
5-3 SURFACE WATER AND SEDIMENTS
The Site area is situated within the drainage basin of the southeast-flowing Alapaha River Local
drainage moves by overland flow to Gum Creek. Gum Creek forms a smaU (less than one a^re)
pond approximately 2,000 feet east of the site. Gum Creek drains this unnamed pond and
discharges to the New River, approximately five miles downstream of the Site. In the Site area,
Gum Creek is primarily a wet-weather stream consisting of a series of pools and small riffle areas
Drainage at the Golden Seed property is to the south, toward the railroad drainage ditch that '
follows the rail spur. The railroad drainage ditch drains into a marshy area adjacent to Gum
Creek via two culverts that pass beneath the railroad tracks. Following periods of rain, this area
contains a series of stagnant pools of water which overflow toward Gum Creek.
5.4 HYDROGEQLOfiV
Groundwater is a significant natural resource in the Site area and has been the subject of many
previous audies Several aquifers of regional significance may be present in this area of the
southeast US. These aquifers include the Surficial Aquifer System (not present in the Site area)
the Intermediate Aquifer System (IAS), and the Floridan Aquifer System (FAS). The IAS consists
of various Hawthorne Group members composed largely of sand, clay, shell zones, and limestone
-------
occurring within a 13-county area of southwest Florida. In Georgia, the Hawthorne consists
chiefly of interbedded clay, sand, and silt and is described as a confining unit in the Site area.
Discontinuous Hawthorne water-bearing zones are present in several areas within Georgia and
Florida. Shallow water-bearing units of the Hawthorne Group are recharged primarily by
precipitation. Discharge from water-bearing zones within the Hawthorne Group appears
primarily to be to local surface waters, although vertical flow to underlying strata is possible.
The FAS is one of the most extensive and prolific water-producing sources in the southeastern
U.S. At the Site, the FAS is overlain by a 300-foot thickness of predominantly fine-grained,
cohesive, plastic sediments of the Hawthorne Group. The system is recharged principally by
rainfall and stream flow in its outcrop area some 25 miles northwest of the Site. The Site and
surrounding area is not a significant recharge area.
5.5 SAMPLING STRATEGY
The original work plan for Marzone OU2 specified the following samples:
• 63 surface soil and 24 subsurface soil samples for onsite analysis using immunoassay
analytical techniques for toxaphene, DDT and gamma-BHC;
• 24 surface soil and 12 subsurface soil samples to be analyzed for volatiles, semivolatiles,
pesticides, and metals by a Contract Laboratory Program lab;
• 4 surface water samples from the railroad drainage ditch, 8 surface water samples from the
wetlands, and 7 surface water samples from Gum Creek to be analyzed for volatiles,
semivolatiles, pesticides, and metals, as well as water quality parameters;
• 4 sediment samples from the railroad drainage ditch, 16 sediment samples from the
wetlands, and 7 sediment samples from Gum Creek to be analyzed for volatiles,
semivolatiles, pesticides, and metals; and
• 7 groundwater samples to be analyzed for volatiles, semivolatiles, pesticides, and metals,
as well as water quality parameters.
Because of various technical problems, the following samples were collected and analyzed:
• 63 surface soil and 24 subsurface soil samples for onsite analysis using immunoassay
analytical techniques for toxaphene, DDT and gamma-BHC;
• 24 surface soil and 12 subsurface soil samples to be analyzed by a Contract Laboratory
Program lab;
-------
TABLE 5-1 :ORGANIC CONTAMINANTS IN SlIRFACF snn ,
CHEMICAL
Heptachlor
Heptachlor epoxide
Gamma-BHC
Delta-BHC
DDT
DDE
ODD
Dieldrin
Endrin
Endosulfan sulfate
Toxaphene
Endrin aldehyde
Gamma-chlordane
Alpha-chlordane
Endrin ketone
Atrazuie
Dalapon
Dinoseb
Dioxin (TEQ)
Di-N-Butylphthalate
1 Fluoranthene
Pyrene
Benzyl Butyl Phthalate
Bis(2-cthylhexy) phthalate
Chiysene
Di-N-Octylphthalate
Benzo(b &/or k)fluoranthene j
Benzo-a-pyrene
(3- &/or 4-) Methvlohenol
CONCENTRATION DETECTED
(UG/KGORPPB)
MINIMUM
4.8J
8.7J
4J
6.8J
15N
0.61J
6.8
55.8
12J
8.8J
320
79
11
35
41
38
22
74
0.00022
370
44J
54J
450
950
80J
690
51J
82J
63J
MAXIMUM
120N
146
4J
21
23,000
2,500
150,000
55.8
19,000
8.8J
100,000
450.5
3,300
1,300
5.900N
85
22
74
0.0091
1,200
92J
54J
2,000
2,200
80J
690
160J
82J
63J
FREQUENCY OF
DETECTIONS
5/29
4/29
1/29
2/29
23/29
22/29
17/29
1/29
8/29
1/29
22/29
3/29
14/29
11/29
5/29
2/13
1/13
1/13
6/6
16/24
. — —
2/24
1/24
7/24
5/24
1/24
1/24
2/24
1/24
1/24
J -Estimatedvalue
N -Presumptivelyidentified
PPB - Parts per billion or micrograms per kilogram
Minimum concentration is that detected above the detection limit
-------
3 surface water samples from the railroad drainage ditch, 8 surface water samples from the
wetlands, and 7 surface water samples from Gum Creek;
4 sediment samples from the railroad drainage ditch, 8 sediment samples from the
wetlands, and 7 sediment samples from Gum Creek; and
7 groundwater samples.
TABLE 5-2:INORGANIC CONTAMINANTS IN SURFACE SOIL
CHEMICAL
Arsenic
Barium
Beryllium
Cadmium
Chromium
Cobalt
Copper
Lead
Antimony
Nickel
Selenium
Vanadium
Zinc
Mercury
Aluminum
Manganese
Calcium
Iron
Magnesium
CONCENTRATION DETECTED
(MG/KGORPPM)
MINIMUM
1.0
8.9
0.16J
1.1
2.6J
0.6
5.4
LJ.9J
3.1J
1.3
1.2J
6.3
35
0.1
630
6.2J
251
1,100
65.1
MAXIMUM
18
229.5
0.6
5.9
26
17.9
1785
280.5
4.2
195.5
1.7
60
20,400
0.14
14,OOOJ
13,600
12,OOOJ
27,000
1020
FREQUENCY OF
DETECTIONS
21/29
21/29
6/29
4/29
26/29
5/5
21/29
28/29
2/29
18/29
3/29
19/29
20/29
8/29
29/29
28/29
15/29
29/29
13/29
PPM - Parts per million or milligrams per kilogram
ND - Not detected
J - Estimated value
Minimum concentration is that detected above the detection limit.
-------
An additional sampling event was conducted in June 1997 for the ecological risk assessment
This event involved soil sampling in five locations, surface water and sediment sampling in nine
locations ( one railroad drainage ditch, two wetlands and six Gum Creek), and tissue sampling In
addition, sampling events were conducted in May 1998 and December 1998 to further delineate
groundwater and subsurface soil contamination. The May 1998 event involved groundwater
sampling at the seven permanent monitoring wells. The December 1998 event involved
groundwater sampling at six of the seven permanent wells (one well was damaged), groundwater
sampling at eight temporary monitoring wells, and subsurface soil sampling around the concrete
pad.
5-5 NATURE AND EXTENT OF CONTAMINATION
Surface and subsurface soils were sampled and analyzed for pesticides, herbicides, metals volatile
organic compounds, and semivolatile organic compounds. Summaries of the results are presented
in Tables 5-1 through 5-4.
TABLE 5-3:0] 3ANIC CONTAMINANTS IN SIIRSTTRFAPP SOTT
CHEMICAL
DDT
DDE
ODD
Endrin
Toxaphene
Gamma-chlordane
Alpha-chlordane
Endrin ketone
Parathion
Di-N-butylphthalate
Benzyl butyl phthalate
Bis(2-ethvlhexyl)Dhthalate
CONCENTRATION DETECTED
(UG/KGORPPB)
MINIMUM
0.97J
0.65JN
0.85J
0.5J
660
0.32J
0.54J
4.3N
31J
490
400
650
MAXIMUM
1000
35
120
140
660
33
35
53
31J
960
580
1,100
FREQUENCY OF
DETECTIONS
12/17
6/17
4/17
5/17
1/17
8/17
5/17
2/17
1/17
9/12
4/12
8/12
J - Estimated value
N - Presumptively identified
PPB - Parts per billion or micrograms per kilogram
Minimum concentration is that detected above the detection limit.
10
-------
The primary pesticides detected in surface soil at OU2 include: toxaphene, 4,4-DDT and its
metabolites and chlordane isomers (gamma-chlordane and alpha-chlordane). Other pesticides
include heptachlor, heptachlor epoxide, gamma-BHC (lindane), delta-BHC, dieldrin, endrin,
endrin aldehyde, and endrin ketone. DDT and its metabolites (DDX) ranged from below
detection limit (BDL) to 175.5 parts per million (ppm). Toxaphene ranged from BDL to 100
ppm. Chlordane ranged from BDL to 4.6 ppm. Three herbicides, atrazine, dalapon, and dinoseb,
were detected in surface soil samples, but were not widespread.
Surface soil was also tested for dioxins. The background surface soil sample had a dioxin toxic
equivalent (TEQ) of 0.0076 parts per billion (ppb). TEQs on-site ranged from 0.00022 to 0.0091
ppb.
Eight pesticides were detected in subsurface soil samples. These include DDX and the two
chlordane isomers found in surface soil. Others included endrin, toxaphene, and endrin ketone.
Parathion was detected in one subsurface soil sample.
TABLE 5-4: INORGANIC CONTAMINANTS IN SUBSURFACE SOIL
CHEMICAL
Arsenic
Beryllium
Cadmium
Nickel
Selenium
Thallium
Vanadium
Zinc
Aluminum
Manganese
Magnesium
CONCENTRATION DETECTED
(MG/KGORPPM)
MINIMUM
2.1J
0.29J
0.2J
0.8 U
1.1
0.74J
6.8
13
4,000
5
50J
MAXIMUM
5.1-
0.29J
0.2J
25
2J
0.74J
64
220
17,000
66
420
FREQUENCY OF
DETECTIONS
8/17
1/17
2/17
10/17
6/17
1/17
17/17
7/17
17/17
13/17
7/17
PPM - Parts per million or milligrams per kilogram
ND - Not detected
J - Estimated value
Minimum concentration is that detected above the detection limit.
11
-------
TABLE 5-5: CONTAMINANTS IN DITCH SURFACE WATERS
CHEMICALS
Delta-BHC
Gariima-BHC (Lindane)
DDE
Endrin
Endrin ketone
Atrazine
Dinoseb
Arsenic
Barium
Cadmium
Cobalt
Chromium
Copper
Nickel
Lead
Vanadium
Zinc
Aluminum
Manganese
Iron
Magnesium
Sodium
Potassium
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
0.16
0.08
0.29
0.22
0.44
0.29
0.12JN
73
11
U
3J
3J
30.8
4J
3
6J
64
268
35
750
2,940
3,400
4,200
MAXIMUM
0.16
0.08
0.29
0.22
0.85
0.94
1.1
14.3
90
2J
3J
3J
47
12J
3.8
8J
1,300
5,200
1,400
4,720
7,900
8,400
11,000
FREQUENCY OF
DETECTIONS
1/4
1/4
1/4
1/4
3/4
2/3
2/3
2/4
4/4
2/4
1/4
1/4
2/4
4/4
2/4
1/4
4/4
3/4
4/4
4/4
4/4
4/4
4/4
PPB - Parts per billion
J - Estimated value
N - Presumptive evidence of presence of material
Minimum concentration is that detected above the detection limit.
12
-------
TABLE 5-6: CONTAMINANTS IN WETLAND SURFACE WATER
CHEMICAL
Alpha-BHC
Beta-BHC
Gamma-BHC(Lindane)
DDT
ODD
Endrin
Toxaphene
Alpha-chlordane
Endrin ketone
Atrazine
2,4-D
Dinoseb
Arsenic
Barium
Cobalt
Chromium
Copper
Lead
Nickel
Thallium
Vanadium
Zinc
Aluminum
Manganese
Calcium
Iron
Magnesium
Potassium
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
0.09
0.17
0.036J
4.6
11
0.15
7.5
0.061J
0.59
0.3 IN
0.14J
0.54J
9.7
15
U
3J
14.7
3.5
8.3
5
7.5
96
145
49
4,700
670
1,500
3,200
MAXIMUM
0.09
0.17
0.2
4.6
11
0.15
13N
0.062
1.6
0.83
0.29J
2.6 ^
20.3
130
6J
19
83
8.6
8.3
5
7.5
1,400
14,000
2,500
48,000
19,000
7,400
17,000
NUMBER OF
DETECTIONS
1/10
1/10
8/10
1/10
1/10
1/10
2/10
2/10
6/10
8/8
2/8
3/8
2/10
10/10
4/10
6/10
8/10
2/10
1/10
1/10
1/10
10/10
9/10
10/10
10/10
10/10
10/10
10/10
N - Presumptive evidence of presence of material
J - Estimated value
Minimum concentration is that detected above the detection limit.
13
-------
Elevated levels of metals were found throughout OU2. Sixteen metals were found at
concentrations greater than two times average background concentration in surface soil samples.
Metals exceeding background concentrations include arsenic, barium, beryllium, chromium,
copper, nickel, vanadium, zinc, manganese, and mercury. Zinc and copper are prevalent om the
Golden Seed property. Arsenic, mercury, and chromium exceeded background concentrations on
the area west and north of the Golden Seed facility. Eleven metals were detected in subsurface
soils at concentrations greater than two times average background concentration in subsurface
soil samples. These included arsenic, beryllium, cadmium, nickel, zinc, and manganese.
TABLE 5-7: CONTAMINANTS IN GUM CREEK SURFACE WATER
CHEMICAL
Beta-BHC
Gamma-BHC(Lindane)
DDD
Dieldrin
Endosulfan sulfate
Endrin
Endrin ketone
Toxaphene
Atrazine
Arsenic
Barium
Chromium
Copper
Lead
Vanadium
Zinc
Aluminum
Manganese
Iron
Sulfate
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
0.03J
0.014J
0.05
0.08
0.18
0.013J
0.52
3.6JN
0.6N
7.6
26
U
6.3
2J
2J
50
147
58
950
2,100
MAXIMUM
0.03J
0.07
0.05
0.08
0.18
0.043J
0.8 .
6. IN
0.89N
7.6
96
11
51.6
24
26J
420
9,500
3,180
12,000
14,000
FREQUENCY OF
DETECTIONS
1/13
7/13
1/13
1/13
1/13
5/13
2/13
2/13
6/7
1/13
13/13
4/13
5/13
9/13
7/13
10/13
10/13
13/13
13/13
7/13
J - Estimated value
N - Presumptive evidence of presence of material
Minimum concentration is that detected above the detection limit.
14
-------
TABLE 5-8: CONTAMINANTS IN DITCH SEDIMENTS
CHEMICAL
DDT
DDE
ODD
Endrin
Heptachlor epoxide
Toxaphene
Endrin aldehyde
Gamma-chlordane
Alpha-chlordane
Atrazine
Fluoranthene
Pyrene
Benzo(a)anthracene
Chiysene
Benzo(b &/or k)fluoranthene
Benzo-a-pyrene
(3- &/or 4-)methylphenol
CHEMICAL
>
Arsenic
Barium
Beryllium
Cadmium
Chromium
Copper
Nickel
Lead
Vanadium
Zinc
Aluminum
Manganese
Iron
Sodium
CONCENTRATION DETECTED
(UG/KGORPPB)
MINIMUM
37
9N
24
180
154
8,500
55J
71C
170C
63
170J
200J
170J
260J
580J
220J
61J
MAXIMUM
20,000
1,190
13,000
240
154
83,000
55J
980*
980*
63
170J
200J
170J
260J
580J
220J
61J
CONCENTRATION DETECTED
(MG/KGORPPM)
MINIMUM
1.3J
9.1
0.3
0.090J
3.8
8.7
3.5
12
7.6J
46
2,500
84
3,000
210
MAXIMUM
14
79
0.3
1.9J
45
300
21
75
79
1,500
33,000
770
37,000
210
FREQUENCY OF
DETECTIONS
5/5
5/5
5/5
2/5
1/5
2/5
1/5
3/5
3/5
1/2
1/4
1/4
1/4
1/4
1/4
1/4
1/4
FREQUENCY OF
DETECTIONS
4/5
5/5
1/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
1/5
15
-------
* Measured as total chlordane
ND- Not detected
J - Estimated value
N - Presumptive evidence of presence of material
C - Confirmed by GC/MS
Minimum concentration is that detected above the detection limit.
Volatile organic compounds were not detected in surface or subsurface soils. Ten semivolatile
organic compounds (SVOCs) were detected in surface soil. Five were polycyclic aromatic
hydrocarbons, four were phthalates, and one was a phenol. Three phthalate compounds were
detected in subsurface soil samples.
Surface water and sediments were also sampled and analyzed for pesticides, herbicides, metals,
volatile organic compounds, and semivolatile organic compounds. Summaries of the results are
presented in Tables 5-5 through 5-10.
Eighteen surface water samples were collected for OU2 in the original sampling event: three
from the ditch, eight from the wetland, and seven from the creek. Nine additional samples were
taken in the June 1997 event: one from the ditch, two from the wetland, and six from the creek
Seven pesticide/herbicide compounds, beta-BHC, gamma-BHC, DDE, endrin, endrin ketone,
atrazme, and dinoseb, were detected in the surface water samples collected from the ditch.
Twelve pesticide and herbicide compounds including toxaphene, endrin ketone, and gamma-BHC
(lindane) were detected in the surface water samples from the wetland. Of the pesticides/
herbicide detected in Gum Creek surface water samples, endrin, toxaphene, lindane and atrazine
were detected most frequently.
In the ditch surface water, fifteen metals were detected at concentrations which were greater than
two times background including chromium, nickel, and lead. Twelve metals were detected in the
wetlands surface water at concentrations exceeding two times background. These metals
included copper, zinc, and manganese. In Gum Creek surface water, eleven metals were found at
concentrations which were greater than two times background including chromium, lead and
manganese.
One volatile organic compound (VOC) was detected in the ditch surface water samples. Toluene
was found at 7 ppb in the background ditch surface water sample. Xylene was detected in the
background surface water sample for the wetland. VOCs were not detected in the surface water
samples for Gum Creek. SVOCs were not detected in surface water samples for the ditch or
wetland. Bis(2-ethylhexyl)phthalate was present in the background surface water sample for Gum
Creek.
Ten pesticide/herbicide compounds were detected in sediment samples obtained from the drainage
ditch. Eleven pesticide/herbicide compounds including DDX, toxaphene, and chlordane isomers
were detected in shallow (0-2 inch) sediment samples from the wetland. Ten pesticide
compounds were detected in the deep (6 - 12 inch) sediment samples from the wetland. In Gum
16
-------
TABLE 5-9: CONTAMINANTS IN WETLAND SEDIMENTS
CHEMICAL
Heptachlor
Heptachlor epoxide
Alpha-BHC
Beta-BHC
Gamma-BHC (Lindane)
DDT
DDE
ODD
Dieldrin
Toxaphene
Gamma-chlordane
Alpha-chlordane
Endrin ketone
Dinoseb
CHEMICAL
Arsenic
Barium
Beryllliurn
Cadmium
Cobalt
Copper
Nickel
Lead
Selenium
Vanadium
Zinc
Manganese
Calcium
Iron
Magnesium
Sodium
Potassium
CONCENTRATION DETECTED
(UG/KGORPPB)
MINIMUM
160N
54
3.8J
20
14
147.4
17
30
156
2,700
15
33
2,300
29
MAXIMUM
160N
193
91
270
99
14,000
1,100
9,020
156
170,000
5,500
2,500
3,200
29
CONCENTRATION DETECTED
(MG/KGORPPM)
MINIMUM
2.1J
3.7
0.3
0.15J
0.250J
5.4
0.770J
3.9
0.98J
12.5
9.8
3.6
73
2,100
64
38
61
MAXIMUM
37
580
0.3
7
17J
850
480
180
3.6J
15.4
4,620
3,300
8,300
30,000
1,600
520
1,700
FREQUENCY OF
DETECTIONS
1/23
2/23
3/23
3/23
4/23
15/23
18/23
16/23
1/23
16/23
14/23
11/23
2/23
1/5
FREQUENCY OF
DETECTIONS
17/23
19/23
1/23
14/23
19/23
22/23
23/23
23/23
6/23
2/73
23/23
23/23
23/23
21/21
21/21
14/21
18/21
J -Estimated value
Minimum concentration is that detected above the detection limit
17
-------
TABLE 5-10: CONTAMINANTS IN GUM CREEK SEDIMENTS
CHEMICAL
DDT
DDE
ODD
Toxaphene
Gamma-chlordane
Alpha-chlordane
CHEMICAL
Arsenic
Barium
Beryllium
Cadmium
Cobalt
Chromium
Copper
Nickel
Lead
Vanadium
Zinc
Mercury
Aluminum
Manganese
Calcium
Iron
Magnesium
Sodium
Potassium
CONCENTRATION DETECTED
(UG/KGORPPB)
MINIMUM
42N
11
10
10,000
21
16
MAXIMUM
93,000
7,900
18,000
22,000
29,000
11,000
CONCENTRATION DETECTED
(MG/KGORPPM)
MINIMUM
0.6
9.2
0.5
0.1 U
0.75J
3.3
2.7
1.1J
7.3
7.1
21
0.59
2,623
10
429
1,800
57.6
190
187
MAXIMUM
40
330
0.5
2.9J
17J
41
1,000
26
290
81
1,500
0.59
42,000
2,400
4,400
37,000
1,000
190
1,100
FREQUENCY OF
DETECTIONS
6/13
8/13
8/13
2/13
6/13
4/13
FREQUENCY OF
DETECTIONS
11/13
13/13
1/13
8/13
9/13
13/13
12/13
13/13
13/13
13/13
13/13
1/13
13/13
13/13
13/13
13/13
13/13
1/13
7/13
N - Presumptive evidence of presence of material
Minimum concentration is that detected above the detection limit.
18
-------
TABLE 5-11: ORGANIC CONTAMINANTS IN GROUNDWATER - MARCH 1996
CHEMICAL
Alpha-BHC
Gamma-BHC
Endrin
Endosulfan II (Beta)
Endrin ketone
Atrazine
2,4-D
2,455-T
Dinoseb
Chloroform
1 , 1 ,2-Trichloroethane
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
0.067
0.019
0.17
0.039
1.2
0.35
0.82
2.1
0.64
2J
U
MAXIMUM
0.083
0.39J
3.9
0.64
5.1
0.71
0.82
2.1
3,400
2J
U
NUMBER OF
DETECTIONS
2/7
3/7
2/7
2/7
2/7
2/7
1/7
1/7
3/7
1/7
1/7
J - Estimated
N - Presumptive evidence of presence of material
Minimum concentration is that detected above the detection limit.
TABLE 5-12: ORGANIC CONTAMINANTS IN GROUNDWATER - MAY 1998
CHEMICAL
Alpha-BHC
Beta-BHC
Gamma-BHC
Endrin
Endrin ketone
Dinoseb
1 ,2-Dichloroethane
1 , 1 ,2-Trichloroethane
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
0.062
0.078JNA
0.065A
0.16JNA
0.068J
0.092J
0.61J
1
MAXIMUM
0.085
0.097JN
0.12
0.44N
5.2
4,300
1.0
1.2
NUMBER OF
DETECTIONS
3/7
2/7
3/7
3/7
4/7
3/7
4/7
2/7
J - Estimated
N - Presumptive evidence of presence of material
A - Average value
Minimum concentration is that detected above the detection limit.
19
-------
TABLE 5-13: ORGANIC CONTAMINANTS IN GROUNDWATER - nF.rFMRF^ 100*
CHEMICAL
Alpha-BHC
Gamma-BHC
Endrin ketone
Atrazine
Dinoseb
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
0.048J
0.028J
0.094
0.012
0.0073
MAXIMUM
0.17
0.5
4.1
1.8
1,100
NUMBER OF
DETECTIONS
4/12
5/12
9/12
8/12
9/12
J - Estimated
N - Presumptive evidence of presence of material
A - Average value
Minimum concentration is that detected above the detection limit.
Creek six pesticide compounds were detected in sediment samples. Two pesticides (heptachlor and
4-chloro-2-methyl phenoxy acetic acid (MCPA)) were detected in background samples but not i
others.
in
Fourteen metals were detected at concentrations greater than two times background in ditch
sediments. These metals include arsenic, chromium, cadmium, nickel, and lead. In the wetland
sediments, fifteen metals were detected at concentrations greater than two times background. Gum
Creek sediment samples contained seventeen metals at concentrations greater than two times
background.
Three VOCs were detected in the background sediment samples collected from the ditch, but were
not detected in other samples. These VOCs were toluene, ethyl benzene, and methyl ethyl ketone
VOCs were not detected in shallow or deep sediment samples from the wetland or the sediment
samples from Gum Creek. Seven SVOCs were detected in one sediment sample from the ditch
Twelve SVOCs were detected in shallow sediment samples and five SVOCs were detected in deep
sediment samples. In Gum Creek, eight SVOCs were detected in the duplicate background sediment
Seven groundwater monitoring wells were installed and developed for the remedial investigation at
OU2. Eight temporary wells were installed for the December 1998 sampling event. Groundwater
samples were analyzed for pesticides and herbicides, volatiles, and semivolatiles (Tables 5-11 through
5-16). Nine pesticides and herbicides were detected in groundwater samples. These included endrin
ketone, atrazine, dinoseb, endrin, alpha-BHC, gamma-BHC (lindane) and endosulfan n. Eighteen
metals were detected in groundwater samples at concentrations which were greater than two times
background. Chloroform, 1,2-dichloroethane, and 1,1,2-trichloroethane were the only VOCs
detected in the groundwater samples. SVOCs were not detected in groundwater samples.
20
-------
TABLE 5-14: INORGANIC CONTAMINANTS IN GROUNDWATER - MARCH 1996
CHEMICAL
Arsenic
Barium
Beryllium
Cadmium
Cobalt
Chromium
Copper
Nickel
Lead
Selenium
Zinc
Aluminum
Manganese
Calcium
Iron
Magnesium
Sodium
Potassium
Sulfate
Ammonia
Total Phosphorus
Nitrate/Nitrite
Chloride
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
11
9
U
17
130
12
29
12J
5
7J
62
2,400
16J
3,400
460
1,700
2,2001
1,7001
9,900
260
50
110
6,800
MAXIMUM
34
160
18JN
17
130
230
1,400
720
50
16J
2,1001
970,000
8,800
180,000
19,000
49,000
220.000J
80,OOOJ
6,300,000
260,000
240,000
70,000
48,000
NUMBER OF
DETECTIONS
2/7
7/7
4/7
1/7
1/7
4/7
7/7
7/7
7/7
2/7
111
3/7
111
7/7
7/7
7/7
7/7
7/7
6/7
7/7
5/7
5/7
6/7
J - Estimated
N - Presumptive evidence of presence of material
Minimum concentration is that detected above the detection limit.
21
-------
TABLE 5-15: INORGANIC CONTAMINANTS IN GROUNDWATER - MAY 1998
CHEMICAL
Arsenic
Barium
Beryllium
Cadmium
Cobalt
Chromium
Copper
Nickel
Lead
Selenium
Zinc
Aluminum
Manganese
Calcium
Iron
Magnesium
Sodium
Potassium
Nitrate/Nitrite
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
4.4
4.4
2
3.6
3.4
36
3.4
2.9
22
2.5
17
160
33
4,400
180
1,100
4,500
4,000
240
MAXIMUM
4.4
350
12
12
89
89
650
400
22
20
1,500
580,000
5,800
150,000
28,000
30,000
140,000
74,000
38,000
NUMBER OF
DETECTIONS
1/7
7/7
3/7
2/7
4/7
3/7
7/7
4/7
1/7
3/7
7/7
7/7
7/7
7/7
6/7
7/7
7/7
111
6/7
tft
J - Estimated
N - Presumptive evidence of presence of material
Minimum concentration is that detected above the detection limit
Principal threat wastes at the site include pesticides (toxaphene, DDT and its metabolites, and
chlordane) and metals in surface soil which may migrate by wind or surface runoff to other surface
soils, surface waters, and sediments. Additional principal threat wastes are pesticides (BHCs),
herbicides (dinoseb) and metals which may migrate by infiltration into the groundwater. Low-level
threat wastes are other pesticides, organics, and metals which were found in low frequency or are
relatively non-mobile.
22
-------
TABLE 5-16: INORGANIC CONTAMINANTS IN GROUNDWATER -DECEMBER 1998
CHEMICAL
Barium
Cobalt
Chromium
Copper
Nickel
Zinc
Aluminum
Manganese
Calcium
Iron
Magnesium
Sodium
Potassium
Sulfate
Nitrate
Nitrite
CONCENTRATION DETECTED
(UG/LORPPB)
MINIMUM
23
20
9.5
8.1
18
9.9
410
5.9
1,300
140
400
3,700
1,000
1,700
260
ND
MAXIMUM
1,200
120
140
850
570
1,700
730,000
7,500
150,000
11,000
49,000
170,000
67,000
5,800,000
66,000
ND
NUMBER OF
DETECTIONS
9/11
2/11
3/11
3/11
2/11
9/11
11/11
10/11
11/11
11/11
11/11
11/11
8/11
6/6
6/6
0/6
J - Estimated
N - Presumptive evidence of presence of material
ND - Not detected
Minimum concentration is that detected above the detection limit.
6.0 SUMMARY OF OPERABLE UNIT TWO 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. Based upon this
analysis it was determined that the surface soil, sediments, and groundwater pose current or potential
risks.
The major human health risks currently associated with OU2 of the Marzone Site are the ingestion
and dermal contact of contaminated soil by actual on-site visitors. For potential future residents, the
23
-------
TABLE 6-1 : CHEMICALS OF POTENTIAL CONCERN FOR HUMAN HF. AT .TH
CHEMICAL
AIpha-BHC
Gamma-BHC
(Lindane)
DDT
DDE
DDD
Endrin
Toxaphene
Gamma-chlordane
Alpha-chlordane
Endrin ketone
Atrazine
Dinoseb
Chloroform
1,1,2-
Trichloroethane
Arsenic
Beryllium
Cadmium
Chromium
Copper
Nickel
Lead
Vanadium
Zinc
Aluminum
Manganese
Iron
Ammonia
Nitrate/Nitrite
SURFACE SOIL
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
SURFACE WATER
Yes
Yes
Yes
Yes
Yes
Yes
Yes
GROUNDWATER
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
24
-------
major risks associated with OU2 are ingestion and dermal contact of contaminated soil and ingestion
of groundwater. Sediment contamination poses a current and future unacceptable ecological risk.
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.
6.1 HUMAN HEALTH RISK ASSESSMENT
6.1.1 CONTAMINANTS OF CONCERN
The chemicals measured in the various environmental media during the RI were evaluated for
inclusion as chemicals of potential concern (COPCs) in the risk assessment by application of screening
criteria. The criteria which resulted in elimination of chemicals included: inorganics whose maximum
concentration did not exceed two times the average background concentration, inorganics that are
essential nutrients or are normal components of human diets, inorganic and organic chemicals whose
maximum concentration in soil or groundwater was lower than a risk-based concentration
corresponding to an excess cancer risk of 1x10-6 or a hazard quotient level of 0.1, as specified by the
EPA Region 3 Risk-Based Concentration Table, and inorganic or organic chemicals whose maximum
detected concentrations in surface water was lower that the Ambient Water Quality Criteria. Table
6-1 lists the chemicals of potential concern for human health for the Site. These chemicals wre then
further evaluated in the baseline risk assessment to determine the chemicals of concern (COCs) that
would require remediation.
Data from the Remedial Investigation indicate that the transfer of contamination from subsurface soil
to groundwater is not a concern. This conclusion is based on two factors. First, few contaminants
detected in subsurface soil were detected in groundwater. Only two organic constituents, endrin and
endrin ketone, were detected in both subsurface soil and groundwater. Second, a comparison of the
highest concentrations of constituents found in subsurface soil with EPA's Soil Screening Levels for
migration to groundwater indicates that additional investigation is not warranted. None of the
compounds exceeds its corresponding soil screening level, indicating that the levels found are not a
concern. Parathion has no soil screening level; however, it was not detected in any of the
groundwater samples and its maximum detection is considerably less than the cleanup value for
methyl parathion of 4,550ug/kg established in the Record ofDecision for Operable Unit 1 ofthe Site.
This indicates that parathion is not likely to migrate to groundwater at levels of concern. Therefore,
subsurface soil is not included in the remedial objectives specified in Section 6.3.
6.1.2 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:
25
-------
A source and mechanism of release from the source,
A transport medium (e.g., surface water, groundwater, air) and mechanisms of migration
through the medium,
The presence or potential presence of a receptor at the exposure point, and
A route of exposure (ingestion, inhalation, dermal adsorption).
If all four elements are present, the pathway is considered complete.
An evaluation was undertaken of all potential exposure pathways which could connect chemical
sources at the Site with potential receptors. All possible pathways were first hypothesized and
evaluated for completeness using EPA's criteria. The current pathways represent exposure pathways
which could 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
TABLE6-2: SURFACES IL EXPOSURE POINT CONCKNTRATTOMS sriMMAPY
CHEMICAL OF
POTENTIAL CONCERN
DDT
DDE
ODD
Endrin
Toxaphene
Gamma-chlordane
Alpha-chlordane
Endrin ketone
Arsenic
Beryllium
Copper
Vanadium
Aluminum
Manganese
Iron
Q*>% TTPT _ O« ««>,- ««„* ,.~_JL
EXPOSURE POINT
CONCENTRATION (MG/KG)
23
2.5
31
2.5
100
1.9
0.29
0.9
11
0.16
286
38
9,883
450
13,862
STATISTICAL
MEASURE
Maximum
Maximum
95%UCL
95% UCL
Maximum
95% UCL
95% UCL
95% UCL
95% UCL
95% UCL
95% UCL
95% UCL
95% UCL
95% UCL
95% UCL
JT— —"• —rr~* ^w.^uwnv** lujui uu mo tumimeuc mean sou concentration
Maximum - Maximum concentration detected of a chemical. Used as a default in place of the
95% UCL, when the 95% UCL exceeds the maximum.
26
-------
The current pathways are:
potential ingestion of surface soils and drainage ditch and wetland sediments by visitors,
potential ingestion of surface water by visitors,
potential dermal exposure by visitors to surface soils and drainage ditch and wetland
sediments,
potential dermal exposure by visitors to surface water, and
potential inhalation exposure by visitors to dust.
The future pathways are:
potential dermal exposure by visitors or residents to surface soil and drainage ditch and
wetland sediments,
potential dermal exposure by residents or visitors to surface water,
potential ingestion of surface soil by visitors or residents,
potential ingestion of surface water by visitors or residents,
potential inhalation exposure by residents to dust, and
potential ingestion of groundwater from a future drinking water well or inhalation of VOCs
released from the groundwater.
TABLE 6-3: SURFACE WATER EXPOSURE POINT CONCENTRATION SUMMARY
CHEMICAL OF
POTENTIAL CONCERN
Gamma-BHC (Lindane)
Toxaphene
Atrazine
Zinc
Aluminum
Manganese
Iron
EXPOSURE POINT
CONCENTRATION (UG/L)
0.03
4.8
0.8
365
9,500
279
12,000
STATISTICAL
MEASURE
95% UCL
95% UCL
95% UCL
95% UCL
Maximum
95% UCL
Maximum
95% UCL - 95 per cent upper confidence limit on the arithmetic mean soil concentration
Maximum - Maximum concentration detected of a chemical. Used as a default in place of the
95% UCL, when the 95% UCL exceeds the maximum.
27
-------
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. The chronic daily intakes were then used in conjunction with cancer potency factors and
noncarcinogenic reference doses to evaluate risk. Exposure-point concentrations for contaminants
in surface soil, surface water, and groundwater are provided in Tables 6-2, 6-3, and 6-4.
The major assumptions about exposure frequency and duration that were included in the exposure
assessment were:
TABLE 6-4: GROUNDWATER EXPOSURE POINT CONCENTRATION SUMMARY
CHEMICAL OF
POTENTIAL CONCERN
Alpha-BHC
Gamma-BHC (Lindane)
Endrin
Endrin ketone
Atrazine
Dinoseb
Chloroform
1 , 1 ,2-Trichloroethane
Arsenic
Beryllium
Cadmium
Chromium
Copper
Nickel
Lead
Zinc
Aluminum
Manganese
Iron
Ammonia
Nitrate/Nitrite
EXPOSURE POINT
CONCENTRATION (UG/L)
0.042
0.09
0.7
1.1
0.2
572
2
1
9
4
3
46
335
143
22
553
163,409
1,822
6,207
73,192
17,688
STATISTICAL MEASURE
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean
Mean - Mean concentration, using one-half the sample quantitation limit for non-detects.
28
-------
TABLE 6-5: CANCER SLOPE FACTORS FOR CHEMICALS OF POTENTIAL CONCERN
CHEMICAL
Alpha-BHC
Gamma-BHC
(Lindane)
DDT
DDE
DDD
Toxaphene
Gamma-chlordane
Alpha-chlordane
Atrazine
Chloroform
1,1,2-
Trichloroethane
Arsenic
Beryllium
Cadmium
Chromium VT
Lead*
CSF(oral)
6.3E+00
1.3E+00
3.4E-01
3.4E-01
2.4E-01
1.1E+00
1.3E+00
1.3E+00
2.2E-01
6.1E-03
5.7E-02
1.5E+00
4.3E+00
NA
NA
NA
CSF(defmal)
1E-H)1
3E+00
7E-01
7E-01
5E-01
2E+00
3E+00
3E+00
4E-01
8E-03
7E-02
8E+00
2E+01
NA
NA
NA
CSF(inhalation)
6.3E400
NA
3.4E-01
NA
NA
1.1E+00
1.3E+00
1.3E+00
NA
8.1E-02
5.6E-02
1.5E+01
8.4E-K)0
6.3E+00
4.2E+01
NA
* Lead is considered a probable human carcinogen; however, no data on cancer slope factors are available.
NA - Not applicable (no data)
CSF - Cancer slope factor (mg/kg/dayy1
1) Future onsite residents were assumed to have an exposure frequency of 3 50 days per year for
30 years. A site visitor who would enter the Site is assumed to have an exposure frequency
to soil and dust of 80 days per year for 10 years. The juvenile visitor is assumed to visit the
wetland and creek area 12 times per year for 10 years.
2) Soil ingestion rates for future onsite residents include a rate of 200 mg/day for children and
100 mg/day for adults. The soil ingestion rate for current use is 100 mg/visit for the site
29
-------
visitor. The surface water ingestion rate is 10 ml/hour for 4 hours/visit for a visitor wading
in the wetland and creek area for a total rate of 40 ml/visit.
3) Dermal contact exposure parameters for surface water for a visitor assume contact 4
times/month for 3 months/year or 12 visits/year for 10 years.
4) In all scenarios a standard body weight of 70 kg for adults, 15 kg for children, and 45 kg for
juveniles was used.
6.1.3 TOXICITY ASSESSMENT
Toxicity assessment is a two-step process whereby the potential hazards associated with route-
specific exposure to a given chemical are (1) identified by reviewing relevant human and animal
studies; and (2) quantified through analysis of dose-response relationships. EPA has conducted
numeroustoxicity assessments that have undergone extensive review within the scientific community.
EPA toxicity assessments and the resultant toxicity values were used in the baseline risk assessment
to determine both carcinogenic and non-carcinogenic risks associated with each chemical of concern
and route of exposure. EPA toxicity values that are used in this assessment include:
cancer slope factors (CSFs) for carcinogenic effects, and
• reference dose values (RfDs) for non-carcinogenic effects.
Cancer slope factors are route-specific values derived only for compounds that have been shown to
cause an increased incidence of tumors in either human or animal studies. The slope factor is an
upper bound estimate of the probability of a response per unit intake of a chemical over a lifetime and
is determined by low-dose extrapolation from human or animal studies. When an animal study is
used, the final slope factor has been adjusted to account for extrapolation of animal data to humans.
If the studies used to derive the slope factor were conducted for less than the life span of the test
organism, the final slope factor has been adjusted to reflect risk associated with lifetime exposure.
Table 6-5 presents cancer slope factors for the chemicals of potential concern (COPCs).
Reference doses (RfDs) have been developed by EPA for indicating the potential for adverse health
effects from exposure to chemicals exhibiting noncarcinogenic effects. Reference doses are ideally
based on studies where either animal or human populations were exposed to a given compound by
a given route of exposure for the major portion of the life span (referred to as a chronic study). The
RfD is derived by determining dose-specific effect levels from all the available quantitative studies,
and applying uncertainty factors to the most appropriate effect level to determine a RfD for humans.
The RfD represents a threshold for toxicity. RfDs are derived such that human lifetime exposure to
a given chemical via a given route at a dose at or below the RfD should not result hi adverse health
effects, even for the most sensitive members of the population. Table 6-6 presents reference doses
for the chemicals of potential concern.
30
-------
TABLE 6-6: REFERENCE DOSES FOR CHEMICALS OF POTENTIAL CONCERN
CHEMICAL
Gamma-BHC (Lindane)
DDT
Endrin
Gamma-chlordane
Alpha-chlordane
Endrin ketone
Atrazine
Dinoseb
Chloroform
1, 1,2-Trichloroethane
Arsenic
Beryllium
Cadmium
Chromium VI
Copper
Nickel
Lead*
Vanadium
Zinc
Aluminum
Manganese
Iron
Nitrate/Nitrite
RfD (oral)
3E-04 *
5E-04
3E-04
6E-05
6E-05
3E-04
3.5E-02
' 1E-03
1E-02
4E-03
3E-04
5E-03
5E-04
5E-03
4E-02
2E-02
NA
7E-03
3E-01
1E-KX)
2.3E-02
3E-01
1E-01
RfD(dennal)
2E-04
3E-04
2E-04
3E-05
3E-05
2E-04
2E-02
5E-04
8E-03
3E-03
6E-05
1E-03
1E-04
1E-03
4E-03
4E-03
NA
1E-03
6E-02
2E-01
5E-03
6E-02
2E-02
RfD(inhalation)
NA
NA
NA
2E-04
2E-04
NA
NA
NA
NA
NA
NA
6E-06
NA
3E-05
NA
NA
NA
NA
NA
NA
1.43E-05
NA
NA
Table only includes COPCs for which reference doses are available.
* Lead produces non-cancer effects; however, no data on reference doses are available.
NA - Not applicable (no data)
RfD - Reference Dose (mg/kg/day)
31
-------
6.1.4 RISK CHARACTERIZATION
Human health risks are characterized for potential carcinogenic and non-carcinogenic effects by
combining exposure and toxicity information. For carcinogens, risks area generally expressed as the
incremental probability of an individual's developing cancer over a lifetime as a result of exposure to
the carcinogen. Excess lifetime cancer risk is calculated from the following equation:
Risk = GDI xSF
where: risk = a unitless probability (e.g., 2 x 10'5) of an individual's developing cancer
GDI * chronic daily intake averaged over 70 years (mg/kg-day)
SF = slope factor, expressed as (mg/kg-day)*1
These risks are probabilities that are generally expressed in scientific notation (e.g., IxlCT6). An
excess lifetime cancer risk of 1 xl Q-6 indicates that an individual experiencing the reasonable maximum
exposure estimate has a 1 in 1,000,000 chance of developing cancer as a result of site-related
exposure. This is referred to as an "excess lifetime cancer risk" because it would be in addition to
the risks of cancer individuals face from other causes such as smoking or exposure to too much sun.
The chance of an individual's developing cancer from all other causes has been estimated to be as
high as one in three. EPA's generally acceptable risk range for site-related exposures is 10"4 to 10"*.
EPA considers individual excess cancer risks in the range of W4 to 10"* as protective; however the ^
1x10 nsk level is generally used as the point of departure for setting cleanup levels at Superfund IB
sites. The point of departure risk level ofIxlO* expresses EPA's preference for remedial actions that
result in risks at the more protective end of the risk range.
Potential concern fornoncarcinogenic effects of a single contaminant in a single medium is expressed
as the hazard quotient (HQ) (or the ratio of the estimated intake derived from the contaminant
concentration in agiven medium to the contaminant's reference dose). A HQ which exceeds one (1)
indicates that the daily intake from a scenario exceeds the chemical's reference dose. By addling 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 ffl 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 HQ is calculated as follows:
Non-cancer HQ = CDI/RfD
where:
GDI = Chronic daily intake
RfD = Reference dose
32
-------
GDI and RfD are expressed in the same units and represent the same exposure period (i.e., chronic,
subchronic, or short-term).
Throughout the risk assessment process, uncertainties associated with evaluation of chemical toxicity
and potential exposures arise. For example uncertainties arise in derivation of toxicity values for
reference doses (RfDs) and carcinogenic slope factors (CSFs), estimation of exposure point
concentrations, fate and transport modeling, exposure assumptions and ecological toxicity data.
Because of the conservative nature of the risk assessment process, risk estimated in this assessment
are likely to be overestimates of the true risk associated with potential exposure at OU #2 of the
Marzone Site. The estimated human health risks for OU #2 are shown in Tables 6-7 through 6-13.
Neither a cancer slope factor nor reference dose value is available for lead. Instead, blood lead
concentrations have been accepted as the best measure of exposure. EPA has developed an
integrated exposure uptake biokinetic model to assess chronic exposures of children to lead. This
model was used to evaluate exposures of future child residents to lead. EPA uses a blood lead level
of 10 ug/dl as the benchmark to evaluate lead exposure. The projected blood lead levels for this site
are below 10 ug/dl for all age groups.
6.2 ECOLOGICAL RISK
6.2.1 ECOLOGICAL SETTING
The Marzone Site is located in a rural area with a combination of light industrial/agriculture and
residential land use. The ecological setting of the Site consists of areas of open fields, scrub/shrub,
drainage, wetlands, and woodlands, with an intermittent stream named Gum Creek. The various
habitats are large and diverse enough, including the riparian corridor, to support a variety of small
wildlife species.
The open fields are located on the northern portion of OU2 of the Site. These grassy areas are kept
mowed or bush-hogged for maintenance. The area surrounding the former facility is considered a
highly disturbed ruderal area dominated by opportunistic grasses and forbes. North of this highly
disturbed area, the habitat consists of ruderal grasslands.
Scrub/shrub habitats are located west of the highly disturbed grassy area and in the central portion
of OU2 of the Site south of the railroad spur. These habitats are relatively small in size and consist
of shrub and sapling layers. Both areas appear to have been previously disturbed either by mowing,
dumping of agriculture remnants (e.g., peanuts), or possibly due to previous contamination (south
of the railroad spur). Vegetative stresses are evident in a 1979 aerial photograph that includes this
disturbed area south of the railroad spur. The vegetation in this photograph is dead. The area
appears to have recovered somewhat, however, evidence of chlorotic conditions are still present.
Gum Creek flows southeast approximately 5 miles where it joins the New River. Gum Creek is an
intermittent stream where it flows through the site. Approximately 1.5 miles downstream, several
33
-------
TABLE 6-7: RISK CHARACTERIZATION SUMMARY - CARCINOGENS - CURRENT USE
Scenario Timeframe: Current
Receptor Population: Visitor
Receptor Age: Juvenile
Media
Soil
Surface
Water
Exposure
Medium
Soil
Soil
Soil
Soil
Exposure
Point
Soil On-
Site, Direct
Contact
Soil On-
Site, Direct
Contact
Soil On-
Site, Direct
Contact
Soil On-
Site, Direct
Contact
Chemical of
Potential
Concern
DDT
ODD
Toxaphene
Arsenic
Ingestion
5x10-7
5x10-7
8x10-6
1x10-6
Inhalation
N/A
N/A
N/A
N/A
Dermal
6x10-7
6x10-7
9x10-6
3x10-7
Soil Risk Total
Surface
Water
Direct
Contact
Toxaphene
2x10-8
-
3x10-7
Surface Water Risk Total
Total Risk
Exposure Route
Total
1.1x10-6
1.1x10-6
1.7x10-5
1.3x10-6
2x10-5
3x10-7
3x10-7
2x10-5
34
-------
TABLE 6-8: RISK CHARACTERIZATION SUMMARY - NON-CARCINOGENS - CURRENT USE
Scenario Timeframe: Current
Receptor Population: Visitor
Receptor Age: Child
Media
Soil
Exposure
Medium
Soil
Soil
Soil
Soil
Soil
Exposure Point
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Chemical of
Potential
Concern
DDT
Gamma-
chlordane
Arsenic
Iron
All other
COCs
Ingestion
0.02
0.02
0.02
0.02
0.028
Inhalation
N/A
N/A
N/A
N/A
N/A
Dermal
0.03
0.02
0.005
0.01
0.021
Soil Risk Total
Total Risk
Exposure Route
Total
0.05
0.05
0.025
0.03
0.049
0.2
0.2
35
-------
TABLE 6-9: RISK CHARACTERIZATION SUMMARY - CARCINOGENS - FUTURE USE
Scenario Timeframe: Future
Receptor Population: Resident
Receptor Age: Child
Media
Soil
Ground
Water
Exposure
Medium
Soil
Soil
Soil
Soil
Ground
Water
Exposure Point
SoilOn-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Chemical of
Potential
Concern
DDT
ODD
Toxaphene
Arsenic
Ingestion
9x10-6
8x10-6
1x10-4
2x10-5
Inhalation
N/A
N/A '
N/A
N/A
Dermal
2x10-6
2x10-6
3x10-5
5x10-8
Soil Risk Total
Ingestion
Alpha-BHC
Arsenic
Beryllium
1x10-6
8x10-5
9x10-5
N/A .
N/A
N/A
N/A
N/A
N/A
Groundwater Risk Total
Total Risk
Exposure Route
Total
1.1x10-5
1x10-5
1.3x10-4
2x10-5
1.7x10-4
1x10-6
8x10-5
9x10-5
1.7x10-4
3.4x10-4
36
-------
TABLE 6-10: RISK CHARACTERIZATION SUMMARY - NON-CARCINOGENS - FUTURE USE
Scenario Timeframe: Future
Receptor Population: Resident
Receptor Age: Child
Media
Soil
Ground
Water
Exposure
Medium
Soil
Soil
Soil
Soil
Soil
Ground
Water
Ground
.Water
Ground
Water
Ground
Water
Ground
Water
Exposure Point
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Soil On-Site,
Direct Contact
Chemical of
Potential
Concern
DDT
Gamma-
chlordane
Arsenic
Iron
All other
COCs
Ingestion
0.6
0.4
0.5
0.6
0.9
Inhalation
N/A
N/A
N/A
N/A
N/A
Dermal
0.2
0.1
0.03
0.04
0.03
Soil Risk Total
Ingestion
Ingestion
Ingestion
Ingestion
Ingestion
Dinoseb
Aluminum
Manganese
Nitrate/ Nitrite
All other
COCs
37
10
5
11
6
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Groundwater Risk Total
Total Risk
Exposure Route
Total
0.8
0.5
0.53
0.64
0.93
3.4
37
10
5
11
6
69
73
37
-------
TABLE 6-1 1 : SUMMARY OF CANCER AND NON-CANCER RISKS BY EXPOSURE
ROUTE - CURRENT USE SCENARIO
Exposure
Route
Inadvertent Ingestion of Soil
Dermal Contact with Soil
Inhalation of Dust
Inadvertent Ingestion Surface
Water
Dermal Contact Surface Water
TOTAL RISK
Site Visitor
Cancer
IE-OS
IE-OS
3E-09
2E-08
3E-07
2E-05
HI
0.1
0,1
0.002
0.002
0.005
0.2
TABLE 6-12: SUMMARY OF CANCER RISKS BY EXPOSURE ROUTE -
FUTURE USE SCENARIO
Exposure Route
Inadvertent Ingestion of Soil
Dermal Contact with Soil
Inhalation of Dust
Inadvertent Ingestion of Surface
Water
Dermal Contact with Surface
Water
Ingestion of Groundwater
Inhalation of VOCs while
Showering
TOTAL RISK
Site Visitor
IE-OS
1E-05
3E-09
2E-08
3E-07
NA
NA
2E-05
Child
Resident
2E-04
4E-05
2E-08
NA
NA
2E-04
NA
4E-04
Adult
Resident
7E-05
7E-05
2E-08
NA
NA
3E-04
2E-06
4E-04
Lifetime
Resident
2E-04
1E-04
3E-08
NA
NA
5E-04
2E-06
8E-04
38
-------
TABLE 6-13: SUMMARY OF NON-CANCER RISKS BY EXPOSURE ROUTE -
FUTURE USE SCENARIO
Exposure Route
Inadvertent Digestion of Soil
Dermal Contact with Soil
Inhalation of Dust
Inadvertent Ingestion of Surface
Water
Dermal Contact with Surface
Water
Ingestion of Groundwater
TOTAL RISK
Site Visitor
0.1
0.1
0.002
0.002
0.005
NA
0.2
Child
Resident
3
0.4
0.02
NA
NA
69
73
Adult
Resident
0.3
0.2
0.005
NA
NA
25
25
Lifetime
Resident
0.8
0.2
0.01
NA
NA
32
33
tributaries flow into the creek forming a perennial stream. During periods of heavy rainfall, the
stream within the site consists of a series of flowing pools and small riffle areas. The banks of the
stream overflow creating a marshy area. The stream flows through a wooded area consisting of little
to no ground cover or understory. The overstory consists of a 90 to 100% canopy cover. This
canopy is consistent along the stream as it flows south of the site.
The wetlands at OU2 of the site are classified as palustrine emergent, palustrine scrub/shrub, and
palustrine forested. These wetlands are located on the southern portion of OU2, most being south
of the railroad spur. Emergent and scrub/shrub wetlands are located along the railroad spur and in
one central area south of the spur. The forested wetlands are located along the flood plain edges of
Gum Creek. Hydrophytic vegetation and evidence of hydric conditions are evident (buttressed
trunks, hypertrophied lenticils, shallow root systems, etc.).
6.2.2 EXPOSURE ASSESSMENT
A complete exposure pathway must exist for a receptor species to be exposed to a contaminant of
concern (COC). The exposure pathway consists of the following elements: a source and mechanism
of COC release to the environment, an environmental transport medium for the released COC, a point
of contact with the contaminated medium, and a route of entry of the COC into the receptor at the
exposure point. An examination of sources, releases, fate and transport mechanisms, exposure points,
and exposure routes is conducted in order to determine the complete exposure pathways that exist
at this site. If any of these elements are missing, the pathway is incomplete and is not considered
further.
39
-------
An evaluation was undertaken of all potential exposure pathways which could connect chemical
sources at the Site with potential receptors. All possible pathways were first hypothesized and
evaluated for completeness using EPA's criteria. The following exposure pathways were developed:
Potential ingestion, dermal contact, or plant uptake of soil contaminants by terrestrial
receptors,
Potential ingestion of contaminated surface water by terrestrial receptors,
Potential dermal exposure to contaminated surface water by aquatic, semi-aquatic, or
terrestrial receptors,
Potential ingestion of or dermal exposure to contaminated sediments by aquatic, semi-
aquatic, or terrestrial receptors,
Potential plant uptake of sediment contaminants by aquatic or semi-aquatic receptors, and
Potential inhalation of contaminants in fugitive dust by terrestrial receptors.
Determining potential exposure routes is key to evaluating the toxic mechanisms associated with the
COCs. Chemical contact can occur through dermal absorption, inhalation, ingestion, and biotransfer.
This evaluation emphasizes the most likely routes of exposure by surfaces soil, surface water, and
sediments. The primary pathways proposed for ecological receptors are related to the drainage ditch,
wetland, Gum Creek, and the surface soils.
6.2.3 THREATENED AND ENDANGERED SPECIES REVIEW
A threatened and endangered and rare (T&E) species review and survey were conducted for OU2
of the Site. Prior to initiation of the T&E field survey, a list of T&E species potentially present in Tift
County was obtained from the Georgia Department of Natural Resources (GA DNR), Wildlife
Resource Division. According to a database search conducted by the GA DNR, there are no known
occurrences of T&E species with the potential to occur on within 3 miles of the site. However, based
on habitat present at the site, a list of T&E species with the potential to occur at the site was
developed. A field survey was conducted to identify the presence of these species. No T&E species
were observed during the survey.
6.2.4 TOXICITY ASSESSMENT
An ecological risk assessment was conducted for OU2 of the Site by the EPA Environmental
Response Team (ERT). The contaminants of potential concern (COPC) were identified using results
from the Remedial Investigation (RI) Report and the ERT sampling event. The primary organic
COPC identified in the RI were cnlordane, DDT, DDE, ODD, and toxaphene. These same
compounds were the most frequently detected chemicals in site specific tissue samples, soil, sediment,
and water samples, and were also detected in earthworm tissue from toxicity tests from the ERT
sampling event. The pesticide data from the ERT sampling event were screened using a risk
-------
characterization process that relates exposure concentrations to concentrations that potentially cause
adverse effects (benchmark values). The exposure concentrations were the highest concentration
detected for each contaminant in the surface water, surface sediment and surface soil samples
collected on site.. The benchmark values are based on the lowest concentration considered to be
protective of the most sensitive organism in a medium, and were derived from peer reviewed
literature and the EPA criteria.
A hazard quotient (HQ) for each COPC is calculated by comparing the exposure concentration to
the benchmark value. An elevated hazard quotient (greater than one) signifies that exposure to the
contaminant may present a risk. Additional data and analysis is necessary to determine if risk actually
exists, as conservative assumptions were used throughout the screening-level risk assessment.
Compounds with HQs of less than one were eliminated from further consideration as a contaminant
of concern (COC). Contaminants for which maximum concentrations of compounds exceeded
benchmarks for water, sediment, and soil are presented in Table 6-7.
Contaminants that were above the benchmark, but detected infrequently, (such as heptachlor epoxide)
were analyzed further. Statistical analysis showed that these contaminants were strongly collocated
with contaminants which were detected more frequently. Additionally, the mechanisms of toxicity
for the chlorinated pesticides at the Site are similar, so that the potential effects to biota would be
comparable for most compounds. Based on these factors, the ecological risk assessment for organics
focused on chlordane, DDT, DDD, DDE, and toxaphene.
Inorganic contaminants were also analyzed in the RI and the ERT study. Several metals (aluminum,
arsenic, cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc) were significantly
elevated. While other metals were detected at the site and still may pose potential risk to biota, they
are typically collocated with the commonly occurring metals.
The organic contaminants were evaluated using four methods: 1) a food chain model, 2) a
comparison between contaminant concentrations measured in surface water and literature-based
values on toxicity of water concentrations to amphibians; 3) the use of soil and water toxicity tests;
and 4) analysis of receptor body tissue. The method used was dependent upon the specific toxicity
mechanism of the COC. Iron was not evaluated in the food chain model because it is considered to
be a direct-acting acute toxicant and does not biomagnify.
Body tissue from earthworms, crayfish, mosquitoes, frogs and small mammals were analyzed to
provide direct measurements of body burdens. The results from these analyses were used in food
chain models to determine the acute and sub-lethal toxicity of site contaminants to birds and
mammals. Soil and water toxicity tests were performed using earthworms and aquatic invertebrates.
41
-------
EXPOSURE
MEDIUM
Wetland
(Surface
water and
sediment)
Wetland
(Surface
water and
sediment)
Soil
Soil and
water
Soil and
water
RECEPTOR
TABLE 6-14: ECOLOGICAL EXPOSURE PATHWAYS OF CONCERN
Aquatic
invertebrates
Amphibians
Terrestrial
invertebrates
Worm-eating,
insect-eating
and
carnivorous
birds
Carnivorous
and
omnivorous
mammals
EXPOSURE ROUTES
Direct contact with
water and sediment;
ingestion of sediment
Direct contact with
water and sediment;
ingestion of sediment
and water
Direct contact with soil
Ingestion of terrestrial
invertebrates, insects, or
vertebrates; ingestion of
aquatic vertebrates;
ingestion of water or soil
Ingestion of terrestrial
vertebrates or aquatic
vertebrates and
invertebrates; Ingestion
of soil or water
ASSESSMENT
ENDPOINT
Structure and function of
wetland community and
aquatic invertebrate
community
Structure and function of
wetland community and
amphibian community
Structure and function of
upland soil communities
Acute and sub-lethal toxicity
to worm-eating, insect-
eating and carnivorous birds
Acute and sub-lethal toxicity
to carnivorous and
omnivorous mammals
MEASUREMENT ENDPOINT
Toxicity of water and sediment to
Hyallela and Ceriodaphnia and
crayfish tissue analysis
Green tree frog and green frog tissue
concentration; comparison of water
data with LOECS
Earthworm toxicity test
Analysis of insect, earthworm, small
mammal and frog tissue and use of
analytical results in food chain model
Analysis of small mammal, crayfish,
and frog tissue and use of analytical
results in food chain model
42
-------
TABLE 6-15: ECOLOGICAL ORGANIC CONTAMINANTS OF CONCERN
CHEMICAL
ODD
Gamma-BHC
DDD
DDE
DDT
Dieldrin
Endrin
Endrin ketone
Toxaphene
DDD
DDE
Alpha-chlordane
Heptachlor
epoxide
MEDIA/UNITS
Water - ug/L
Water - ug/L
Soil - ug/kg
Soil - ug/kg
Soil - ug/kg
Soil - ug/kg
Soil - ug/kg
Soil - ug/kg
Soil - ug/kg
Sediment - ug/kg
Sediment - ug/kg
Sediment - ug/kg
Sediment - ug/kg
MAXIMUM
CONCENTRATI
ON
0.05
0.2
5,800
1,500
8,744
720
650
680
21,000
5,600
1,200
1,100
190
BENCHMARK
0.00641
0.081
5002
5002
5002
5002
5002
5002
5002
3.3'
3.31
1.71
53
HAZARD
QUOTIENT
7.8
2.5
11.60
3.00
17.49
1.44
1.30
1.36
42.00
1696.97
363.64
647.06
38.00
1 Region 4 Waste Management Division Screening Values for Hazardous Waste Sites
2 Dutch Soil Cleanup (Interim) Act, criteria for moderate soil contamination that requires further
study
3 Persuad et al. 1992 (I,HI.)
6.2.5 RISK ASSESSMENT
The ERT study made the following conclusions regarding ecological risk at the Marzone OU2 Site.
Based on the results of the RI toxicity tests, the pesticide and metals present in crayfish tissue,
and the potential risk to amphibians posed by DDT and some metals, there appears to be a
potential threat to the overall functioning of the wetland community as well as individual
receptors.
43
-------
Based on the presence of pesticides and metals in earthworm tissue and the mortality results
from earthworm toxicity tests, there is potential risk to soil communities.
The results of the hazard quotient calculations for worm-eating birds (using American Robin
as a measurement endpoint) suggest that there is a potential risk associated with pesticides
and aluminum, cadmium, chromium, copper, lead and zinc at the Marzone OU2 Site.
The results of the hazard quotient calculations for insectivorous birds (using Red Winged
Blackbird as a measurement endpoint) suggest that there is no potential risk associated with
pesticides at the Marzone OU2 Site. The risk associated with metals to insectivorous birds
could not be assessed.
with pesticides and metals at the Marzone OU2 Site.
The results of the hazard quotient calculations for carnivorous mammals (using Red Fox as
ameasurement endpoint) suggest that there is no potential risk associated with pesticides but
there is nsk from aluminum at the Marzone OU2 Site.
The results of the hazard quotient calculations for omnivorous mammals (using Raccoon as
a measurement endpoint) suggest that there is no potential risk associated with pesticides, but
there is nsk from aluminum and manganese at the Marzone OU2 Site.
Thefollowing contaminants wereretained as ecological COCs: chlordane, DDT, DDE DDD
toxaphene, aluminum, arsenic, cadmium, chromium, copper, iron, lead,' magnesium!
manganese, and zinc.
6.3 REMEDIATION OBJECTIVES
The remedial action objectives for Marzone OU2 are:
1)
2)
3)
containment or treatment of all contaminated surface soils above health-based or ecological
action levels,
containment or treatment of contaminated sediment above ecological action levels, and
restoration of ground water to drinking water levels.
Thecleanup.of surface sod and groundwater to residential use or drinking water action levels is based
on toe anticipated use of the Marzone OU2 site as residential property. Although the site has been
used as commerciaVindustrial property in the past, residential neighborhoods are located near the
bite. The selected response action will address current human health risks to on-site visitors and
ecological nsks and will address future human health risks to residents, by removing or treating
44
-------
contaminated soil and sediment and by treating or containing contaminated groundwater. Subsurface
soil is not included in the remedial objectives for the reasons specified in Section 6.1.1.
TABLE 6-16: SUMMARY OF SOIL AND SEDIMENT REMEDIATION PERFORMANCE
STANDARDS FOR CONTAMINANTS OF CONCERN
COMPOUND
DDT
DDE
ODD
Toxaphene
alpha - chlordane
gamma-chlordane
Copper
Lead
Zinc
MEDIUM
SURFACE SOIL
(MG/KG)
1.0*
1.0*
2.0*
0.4*
0.1**
0.1**
20**
330**
100**
SEDIMENT
(MG/KG)**
5.0
5.0
5.0
3.0
0.1
0.1
20
330
100
* Surface soil performance standards based on protection of future residents at a 10* calculated cancer risk level
for direct contact
* * Surface soil or sediment performance standards based on ecological risk; surface soil standards also protective
of future residents at a 10"6 calculated cancer risk level for direct contact and a Hazard Index of less than 1.0
for non-carcinogens
The establishment of health-based cleanup goals serves as an important 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 established by
back-calculating a health protective contaminant concentration, given a target cancer risk or hazard
index 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.
The soils at the Marzone OU2 site currently contain concentrations of Site-related contaminants at
levels which would pose an unacceptable risk (cumulative risk in excess of 10"6 for cancer risks and/or
hazard indices in excess of 1 for non-cancer risks) to human health for future on-site residents
exposed to the soil arid groundwater and for ecological receptors exposed to soil, sediments, and
45
-------
surfacewater Actual or threatened releases of hazardous substances from this Site
TABLE 6-17: SUMMARY OF GROUNDWATER REMEDIATION PERFORMANCE STANDARDS
FOR CONTAMINANTS OF CONCERN
—• . .
•^•
PERFORMANCE STANDARD (UG/L)
COMPOUND
' Aluminum
11111 • IIM.I
Beryllium
•••••^—•^^MH^M
Cadmium
-• i.
Manganese
5**
Nickel
Nitrate/Nitrite
alpha-BHC
1 8,611 *
——•>••—^™™
1.000 (MCL for nitrite)
0.03 ***
gamma-BHC
Endrin
0.2**
2**
••^••••••a
7**
, Dinoseb
* Calculated value for Hazard Quotient = 1
** EPA Maximum Contaminant Level
*** EPA Action Level
?16dSor,1S ^ TTT*8 °f COnCBni for °U2 Of the Site •» ^ained in Tables 6-15 a
excL^eheLlTPHT 'T bfen generated tO enSUre treatment of contaminated soil wht
ST±51!±S^
7-° DESCRIPTTON OF AT.TFRMATTVCC
Two alteratives for the remediation of contaminated soU and sediment at OU#2 of the
Marzone site were evaluated in depth in the Feasibility Study Report and Ihrted h he
ZSSft r ** .^ ^^ ^ ^ N° Action -temttJ Two alternate for
remediation of contaminated groundwater also were evaluated in J—"-
oo
» * i summarize the alternatives and their costs. For the soil and
alternatives, sub-alternative A includes complete excavation of amftteirik
dSve^ medrdWet1^ "b'
alternative B ,s a modification which includes complete excavation of surface soils and
46
-------
drainage ditch sediments. In addition, wetland sediments which exceed performance
standards in the non-wooded portion(s) of the wetland area (Le., "hot-spot" areas) will also
be removed. For the wetlands, EPA initially only considered excavation of all areas which
exceeded performance standards (sub-alternative A). However, after consideration of the
adverse impacts of remediation in the wooded areas of the wetlands, EPA added sub-
alternative B to allow excavation of the "hot-spot" areas while preserving the wooded
wetland areas.
The site-specific alternatives analyzed in the Feasibility Study represented a range of distinct
waste-management strategies addressing the human health and environmental concerns. Eight
remedial technologies for containment or treatment of soil or groundwater were analyzed.
Two technologies for soil and sediment and two technologies for groundwater were retained
as the most effective for this site. Although the selected remedial alternative will be further
refined as necessary during the predesign phase, the analysis presented below reflects the
fundamental components of the various alternatives considered feasible for this Site.
7.1 SOIL AND SEDIMENT ALTERNATIVES
Table 7-1: Operable Unit #2 Soil Alternatives
Alternative Number
1
2A/B
3A/B
Remedial Action
No Action
Excavation & Onsite Treatment with
Solidification/Stabilization; Onsite Disposal
Excavation & Offsite Disposal
Present Worth
$0
A - $2,952,850
B- $1,431,560
A - $2,988,840
B - $1,596,900
7-1.1 ALTERNATIVE NO. 1 - NO FURTHER 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 further action to minimize the impact soil contamination has on the area.
Soil contamination would remain and possibly migrate due to surface runoff. There is no cost
for this alternative.
7.1.2 ALTERNATIVE NO. 2 A/B - EXCAVATION AND SOLIDIFICATION/
STABILIZATION WITH ONSITE DISPOSAL
This alternative involves excavating contaminated surface soil and sediments necessary to
meet the performance standards. Onsite treatment would be solidification/stabilization which
uses cement or other pozzolanic material to bind the contaminants to the soil The treated
47
-------
soil would be backfilled onsite and covered with a layer of vegetated topsoil. The final
treatment system would depend on the outcome of treatability testing and would be
determined during the remedial design phase. Treated soil would be subject to the Toxicity
Characteristic Leaching Procedure (TCLP) and other tests to determine if treatment was
effective. If the soil mixture failed the tests, it would be retreated until the test was passed.
Excavation and treatment of contaminated soils and sediments will remove source material
which is causing contamination of Gum Creek surface water and sediment. Removal of this v
source contamination will result hi a reduction in surface water and sediment contamination
in Gum Creek. Restoration and/or mitigation of destroyed wetlands would be required.
Alternative 2 has been divided into two sub-alternatives which vary hi scope. Alternative 2A
would consist of excavating all contaminated soil and sediments necessary to meet the
remedial action objectives, which involves an estimated 14,300 cubic yards. Under
Alternative 2B, surface soils and drainage ditch soils would be excavated and treated.
Wetland sediment in the "hot-spot" areas also would be excavated and treated. Contaminated
wetland sediment in the wooded area would remain in place, but would be monitored for at
least five years until an acceptable level of ecological risk is achieved. Monitoring stations
could include the area immediately south of the Golden Seed facility (Area 1), an area halfway
between U.S. Highway 41 and Area 1 (Area 2), an area near the intersection of Gum Creek
and U.S. Highway 41 (Area 3), and an area at the pond located southeast of U.S. Highway
41 (Area 4). This sub-alternative is included because the destruction of wetland caused by
remediating the less accessible wetland sediment could outweigh the benefit of removing the
contamination. The estimated volume of soil for Alternative 2B is 6,300 cubic yards. The cost
of this alternative is estimated to be $2,952,850, if all contaminated soil and sediment is
excavated and treated and $1,432,560, if surface soil, drainage ditch, and "hot-spot" areas are
excavated and treated. For alternatives 2A and 2B, the expected outcome is that residential
use of the non-wetland area would be available when the surface soil remedy was completed
(approximately two years after initiation).
7.1.3 ALTERNATIVE NO. 3 A/B - EXCAVATION AND OFFSITE DISPOSAL
This alternative 'involves excavating contaminated surface soil and sediment necessary to meet the
remedial action objectives and transporting it offsite for disposal. The excavated area would be
backfilled with clean topsoil. If the soil is characterized as a RCRA hazardous waste, it would be
transported to a RCRA Subtitle C disposal facility and pretreated, if necessary, at the facility before
disposal. If the soil is characterized as a RCRA non-hazardous waste (as expected based on Marzone
OU1 characteristics), it would be transported to a RCRA Subtitle D disposal facility. Excavation and
disposal of contaminated soils and sediments will remove source material which is causing
contamination of Gum Creek surface water and sediment. Removal of this source contamination will
result in a reduction in surface water and sediment contamination in Gum Creek. Restoration and/or
mitigation of destroyed wetlands would be required.
Alternative 3 has been divided into two alternatives which vary in scope. Alternative 3 A would
consist of excavating all contaminated soil and sediments necessary to immediately meet the remedial
action objectives, which involves an estimated 14,300 cubic yards. Under Alternative 3B, surface
soils and drainage ditch soils would be excavated and treated. .Wetland sediment in the ".hot-spot"
'areas also would be excavated and treated. Contaminated wetland sediment in the wooded area
would remain hi place, but would be monitored for at least five years until an acceptable level of
ecological risk is achieved. Monitoring stations could include the area immediately south of the
48
-------
Golden Seed facility (Area 1), an area halfway between U.S. Kghway 41 and Area 1 (Area 2), an
area near the intersection of Gum Creek and U.S. Highway 41 (Area 3), and an area at the pond
located southeast of U.S. Highway 41 (Area 4). this sub-alternative is included because the
destruction of wetland caused by remediating the less accessible wetland sediment could outweigh
the benefit of removing the contamination. The estimated volume of soil for Alternative 3B is 6,300
cubic yards. If the soil is not characterized as a RCRA hazardous waste (based on Marzone GUI soil
characteristics), it would be transported to a Subtitle D landfill. The estimated cost of this alternative
would be $2,988,840 for all contaminated soil and sediment and $1,596,900 if surface soil, drainage
ditch, and "hot-spot" areas are excavated. For this alternative, the expected outcome is that
residential use at the non-wetland area would be available when the remedy was completed (less than
one year after initiation).
7.2 GROUNDWATER ALTERNATIVES
7.2.1 ALTERNATIVE NO. 1 - NO ACTION ALTERNATIVE
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
further action to minimize the impact groundwater contamination has on the area. Groundwater
contamination would remain and possibly migrate off-site. There is no cost for this alternative.
Table 7-2: Operable Unit #2 Groundwater Alternatives
Alternative Number
1
2
3
Remedial Action
No Action
Monitored Natural Attenuation
Funnel and Gate
Present Worth
$0
$477,676
$2,696,966
7.2.2 ALTERNATIVE NO. 2 - MONITORED NATURAL ATTENUATION
This alternative is based on groundwater data which has indicated that groundwater contamination
may be naturally attenuating as it moves across the site, based on three sampling events conducted
since 1996. Multiple sampling events over an extended period of time will be necessary to confirm
that natural attenuation is effective at this she. Natural attenuation is a combination of processes
which act to reduce the level of contamination in groundwater. These processes include
biodegradation, adsorption, dilution, and dispersion. Under this alternative, EPA would monitor
groundwater for a period of at least five years to ensure that natural attenuation was effectively
reducing groundwater contamination. At least two additional groundwater monitoring wells, one
located to the west of the Golden Seed facility and another located to the southeast of MW-02, would
be installed to provide better coverage of the groundwater contamination and its movement. After
five'years, a contingency remedy of a passive in-situ treatment system would be implemented at
EPA's sole discretion, if monitoring'resultsdid not confirm that natural attenuation was effective. The
cost for this alternative, without the treatment contingency, is estimated to be $477,676. For this
49
-------
7.2.3
50
-------
for this alternative is estimated to be $2,696,966. For this alternative, the expected outcome is the
availability of groundwater for drinking water uses when cleanup levels are achieved (at least 30
years).
8-° 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 NCR The major objective of the FS was to develop, screen, and evaluate alternatives
for the remediation of Operable Unit Two at the Marzone site. The remedial alternatives selected
from the screening process were evaluated using the following nine evaluation criteria:
• Overall protection of human health and the environment.
• Compliance with applicable and/or relevant and appropriate Federal or State public
health or environmental standards.
• Long-term .effectiveness 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.
• Acceptance by the State.
• Acceptance by the Community.
The NCP categorizes the nine criteria into three groups:
W 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;
(2) Primary Balancing Criteria - long-term effectiveness and permanence; reduction of toxicity,
mobility, or volume; short-termeffectiveness; implementability, and cost are primary balancing factors
used to weigh major trade-offs among alternative hazardous waste management strategies; and
(3) Modifying 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.
51
-------
The selected alternative must meet the requirement for overall protection of human health and the
environment and comply with all ARARs or be granted a waiver for compliance with ARARs. Any
alternative 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.
The following analysis is a summary of the evaluation of alternatives for remediating OU2 of the
Marzone 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
Overall protection of human health and the environment addresses whether each alternative provides
adequate protection of human health and the environment and describes how risks posed tlirough
each exposure pathway are eliminated, reduced, or controlled through treatment, engineering
controls, and/or institutional controls.
Soil alternative 1 would not contain or remediate the soil or sediment contamination. Neither would
surface water contamination be reduced. Cleanup levels for soil would not be achieved with
alternative 1, and alternative 1 therefore would not provide adequate protection of human health and
the environment. Since alternative 1 does not meet a threshold criteria, it will not be discussed further
in the document. Soil alternative 2 would remediate contaminated soil and sediment with onsite
treatment to reduced risk levels. Soil alternative 3 would remove the contaminated soil from the site
to reduce risks. Both alternatives would provide protection from exposure due to direct contact or
soil ingestion. Sub-alternative B for both alternatives would be less effective than sub-alternative A,
since some contaminated sediment would remain in place, but each sub-alternative B is still protective
of human health and the environment and is balanced by a reduced overall destruction of the
wetlands. For soil alternatives 2 and 3, cleanup would reduce human health risks to a W6 additional
cancer risk for direct contact with soils by future residents, which is within EPA's acceptable risk
range. Excavation and treatment or disposal of contaminated soils and sediments will remove source
material which is causing contamination of Gum Creek surface water and sediment. Removal of this
source contamination under soil alternatives 2 or 3 will result in a reduction in surface water and
sediment contamination in Gum Creek.
Groundwater alternative 1 would not contain, remediate, or adequately monitor groundwater
contamination. EPA would not know if cleanup levels for groundwater were achieved with
alternative 1, and alternative 1, therefore, would not have a basis for taking additional action, if
necessary, to provide adequate protection of human health and the environment. Since alternative
1 does not meet a threshold criteria, it will not be discussed further in the document. Groundwater
alternative 2 would provide performance monitoring to verify that natural attenuation was reducing
contamination in the groundwater to cleanup levels. A contingency treatment alternative would be
implemented if groundwater monitoring did not demonstrate that natural attenuation was effective.
Groundwater alternative 3 would provide treatment of contaminated groundwater to meet cleanup
levels. Both alternatives would provide long-term protection from exposure due to ingestion of
groundwater, since cleanup would reduce contamination to EPA Safe Drinking Water Act Maximum
Contaminant Levels.
52
-------
8.2 COMPLIANCE WITH ARARS
Section 121(d) of CERCLA requires that remedial actions at CERCLA sites at least attain legally
applicable or relevant and appropriate Federal and State requirements, standards, criteria, and
limitations which are collectively referred to as "ARARs," unless such ARARs are waived under
CERCLA Section 121 (d)(4). Applicable requirements are those substantive environmental protectio n
requirements, criteria, or limitations promulgated under Federal or State law that specifically address
hazardous substances, the remedial actions to be implemented at the site, the location of the site, or
other circumstances present at the site. Relevant and appropriate requirements are those substantive
environmental protection requirements, criteria, or limitations promulgated under Federal or State
law which, while not applicable to the hazardous materials found at the site, the remedial action itself,
the site location or other circumstances at the site, nevertheless address problems or situations
sufficiently similar to those encountered at the site that their use is well-suited to the site. Compliance
with ARARs addresses whether a remedy will meet all of the applicable or relevant and appropriate
requirements of other Federal and State environmental statutes or provides a basis for invoking a
waiver.
Soil alternatives 2 and 3 would comply with all Federal or State ARARs. Contaminant-specific
ARARs would be met through excavation and treatment or disposal of contaminated soiL All
excavation, storage, handling, treatment and disposal of contaminated soil would be conducted in
accordance with applicable RCRA requirements. Off-site disposal of contaminated soil under Soil
alternative 3 would be at a permitted RCRA Subtitle C, or Subtitle D landfill, as appropriate. During
treatment, air emissions from the site would be monitored to ensure compliance with the Clean Air
Act. Air monitoring would be conducted to ensure that contaminant concentrations do hot exceed
levels considered to be safe for human health. If levels are exceeded, mitigative procedures would
be employed to prevent harmful levels of air emissions from impacting on-site workers or from
leaving the Site. RCRA design standards would be incorporated into the remedial design of all
remedial activities.
Drinking water standards would be met by both groundwater alternatives 2 and 3. However, the time
period for alternative 2 may be longer than that for alternative 3 (estimated at 30 years).
Primary Balancing Criteria
8.3 LONG-TERM EFFECTIVENESS AND PERMANENCE
Long-term effectiveness and permanence refers to expected residual risk and the ability of a remedy
to maintain reliable protection of human health and the environment over time, once clean-up levels
have been met This criterion includes the consideration of residual risk and the adequacy and
reliability of controls.
Soil alternatives 2 and 3 would provide long-term effectiveness through removal and treatment or
disposal of contaminated soils. If contaminated soil remains on site above levels which allow for
unrestricted use, a review at least every five years would be required to ensure that the remediation
continued to protect human health and the environment. Sub-alternative B for both alternatives would
be less effective, since some contaminated sediment would remain in place, but these sub-alternatives
are still protective of human health and.the environment and are balanced by reduced overall
destruction of the wetlands. Groundwater alternatives 2 and 3 would provide long-term effectiveness
through reduction of contamination by natural attenuation or active treatment.
53
-------
The alternatives increase in long-term effectiveness and permanence as more treatment options are
included. Therefore, soil alternative 2 and groundwater alternative 3 provide greater long-term
effectiveness and permanence than soil alternative 3 and groundwater alternative 2.
8.4 REDUCTION OF TOXICITY. MOBILITY OR VOLUME THROUGH TREATMENT
Reduction of toxicity, mobility, or volume through treatment refers to the anticipated performance
of the treatment technologies that may be included as part of the remedy, Soil alternative 2 would
reduce mobility and toxicity through treatment; however, volume would increase. Soil alternative 3
would reduce mobility of contamination by removing contaminated soil off-site and placing the soil
in a landfill. Toxicity and volume would remain the same if pretreatment was not required. Toxicity
would be reduced if pretreatment was required before disposal at a RCRA Subtitle C facility. Sub-
alternative B for alternatives 2 and 3 would reduce toxicity and mobility less than sub-alternative A,
since some contaminated sediment would remain hi place.
Groundwater alternative 2 would not utilize treatment to reduce toxicity, mobility, or volume, unless
the contingency is implemented. However, this alternative takes advantage of natural processes to
reduce toxicity and mobility of contaminants. Groundwater alternative 3 would utilize treatment to
reduce toxicity of contaminants.
8.5 SHORT-TERM EFFECTIVENESS
Short-term effectiveness addresses the period of time needed to implement the remedy and any
adverse impacts that may be posed to workers and the community during construction and operation
of the remedy until clean-up goals are achieved. Soil alternative 2 (A or B) would require
approximately 2 years and soil alternative 3 (A or B) would require approximately 1 year to
implement. Appropriate monitoring and engineering controls would be applied to reduce fugitive
dust, noise and risks to on-site remedial workers and nearby workers and residents for soil
alternatives 2 or 3.
Groundwater alternative 2 would require approximately 15 months to implement (including 12
months for treatability studies and modeling). Groundwater alternative 3 would require
approximately 14 months to implement. For administrative purposes EPA is assuming that the time
to reach cleanup levels for alternatives 2 and 3 will be at least 30 years.
8.6 IMPLEMENT ABILITY
Implementability addresses the technical and administrative feasibility of a remedy from design
through construction and operation. Factors such as availability of services and materials,
administrative feasibility, and coordination with other governmental entities are also considered.
Technological expertise, services, equipment and materials are adequately available for the
implementation of soil alternatives 2 and 3. Soil alternative 2 would require a longer period than
alternative 3 to implement due to the on-site treatment of the contaminated soil. Technological
expertise, services, equipment and materials are also adequately available for the implementation of
groundwater alternatives 2 and 3. Groundwater alternatives 2 and 3 would require approximately
the same time to implement.
54
-------
8.7 COST
The total present worth cost of soH alternative 2 is approximately $2,952,851 ($2,756,851 for capital
cost and $196,000 for operations and maintenance (O&M) costs) if all contaminated soil and
SC?mf "1 !?J?fvated *"* ***** (sub-alternative A) and $1,432,563 ($1,255,271 for capital costs
and $177,292 for O&M costs) if some wetland sediments are not excavated (sub-alternative B) For
disposal at a non-hazardous waste landfill, the total present worth cost for soil alternative 3 is
approximately $2,988,838 ($2,948,838 for capital costs and $40,000 for O&M costs) if all
STSS^STl"011 ai?d1sediment is removed (sub-alternative A) and approximately $1,596 874
($1,493,082 for capital costs and $103,792 for O&M costs) if some wetland sediments are not
excavated (sub-alternative B).
For groundwater alternative 2, the total present cost is estimated to be $461,426. The estimated
25?i£*t.£r additi°nal1wells *** featability studies is $181,838 and the estimated O&M cost is
J2795S9. The cost for the contingency would be the same as for groundwater alternative 3 The
cost for groundwater alternative 3 is approximately $2,696,966. . The estimated capital cost is
$2,501,181 and the estimated O&M cost is $195,785.
Modifying Criteria
8.8 STATE ACCEPTANCE
The State of Georgia, as represented by the Georgia Environmental Protection Division (GaEPD)
has been the support agency during the Remedial Investigation and Feasibility Study process for
Marzsrte.Inaccori^^
Pr°CeSS' fGe°r^
8-9 COMMUNITY ACCEPT AMrE
During the public comment period, comments were received on the proposed plan. See Appendix
A-Responsiveness Summary for EPA's responses to the comments ee Appendix
9-° SUMMARY OF SELECTED REMEDV
Based upon consideration of the requirements of CERCLA, the NCP, the detailed analysis of
alternatives and public and state comments, EPA has selected a remedy for Operable Unit 2 of the
Site. The selected remedy is Alternative 3B for soils and sediments and Alternative 2 for
groundwater. The soil and sediment remedy provides for the following:
1. Excavation and off-site disposal of surface soils which exceed the surface soil performance
standards.
2. Excavation and off-site disposal of sediments, from the railroad drainage ditch beginning at
the culverts at the southernmost point of the railroad spur continuing in a northeasterly
direction, which exceed the sediment performance standards
55
-------
3. Excavation and off-site disposal of sediments, in the non-wooded wetland area south of the
railroad spur, which exceed the sediment performance standards.
4. Transportation of contaminated soil and sediment to a permitted Subtitle C or D landfill. JMk
5. Restoration (backfilling, grading, and seeding or replanting vegetation) of surface soil and
wetland areas.
6. Confirmation sampling of soil and sediment to verify that remaining soil and sediment is below
performance standards.
7. Monitoring of wetland and creek area in the wooded area for at least five years to determine
if remaining contamination is naturally attenuating. EPA would consider additional remedial
actions, if contamination does not appear to be naturally attenuating.
This alternative was selected because the destruction of wetland caused by remediating the
inaccessible wetland sediment would outweigh the benefit of removing the contamination. If the soil
is not characterized as a RCRA hazardous waste (as anticipated based on Marzone OU1 soil
characteristics), it may be transported to a Subtitle D landfill. Excavation and disposal of
contaminated soils and sediments will remove source material which is causing contamination of Gum
Creek surface water and sediment. Removal of this source contamination will result in a reduction
in surface water and sediment contamination in Gum Creek.
The selected groundwater remedy is Alternative 2 - monitored natural attenuation. This selected
remedy is based on groundwater data which have indicated that groundwater contamination may be
naturally attenuating as it moves across the site. Natural attenuation is a combination of processes
which act to reduce the level of contamination in groundwater. These processes include
biodegradation, adsorption, dilution, and volatilization. The major components of the groundwater
remedy are as follows:
1. Installation of at least two additional groundwater monitoring wells, one located to the west
of the Golden Seed facility and another located to the southeast of MW-02 to provide better
coverage of the groundwater contamination and its movement.
2. Annual groundwater monitoring for at least five years for the contaminants of concern, as
well as potential transformation products and geochemical parameters.
3. Review of groundwater data after five years to determine if natural attenuation is effective.
A contingency remedy of an in-situ treatment wall may be implemented at EPA's sole
discretion, if results did not confirm that natural attenuation was effective.
4. Institutional controls to restrict use of contaminated groundwater.
The contingency for a funnel-and-gate system is included in this alternative, because of uncertainties
with the natural attenuation process. Groundwater monitoring data indicate that most contaminants
arc decreasing in concentration, especially for dinoseb and the more toxic metals. For BHCs and
other metals, evidence of natural attenuation is inconclusive. Temporary monitoring wells located
between the facility at Marzone OU1 and the Golden Seed portion of Marzone OU2 demonstrate the
presence of BHCs in this area, suggesting that Marzone OU1 may have contributed to the BHC
56
-------
contamination in OU2. The remedial action at OU1 has removed the source of contamination to the
ground water (contaminated soil). Treatment of contaminated groundwater at OU1 is ongoing in a
remedial design pilot study. The OU1 remedial action and remedial design pilot study and its
outcome may therefore result in a decrease in BHC concentrations at OU2 over time, since source
material at OU1 has been removed. However, the effects of OU1 actions on OU2 groundwater
quality are uncertain, because the contribution of OU 1 contamination to OU2 groundwater is not fully
understood at this time.
EPA will review and analyze data from the OU2 monitoring wells after five years. If the data does
not demonstrate a sufficient decline in concentration, EPA may, at its sole discretion, implement the
contingency remedy of an in-situ treatment wall In addition, if the data demonstrates to EPA that
OU1 activities have contributed to BHC groundwater contamination at OU2, but that the OU1
remedial action and natural attenuation are not effective in reducing BHC concentrations, EPA would
consider additional remedial actions at OU1.
At the completion of this remedy, the additional cancer risk associated with this Site has been
calculated at 10"6 for surface soils and sediments or more protective levels necessary for ecological
protection. Groundwater performance standards are established to meet EPA's Maximum
Contaminant Levels (MCLs) for drinking water or to meet a 10'6 additional cancer risk level, if MCLs
are not available. The combined total present worth cost of the selected remedy, Alternatives 3B for
soil/sediment and 2 for groundwater, is estimated to be $1,910,298.
9.1 SOIL AND SEDIMENT REMEDY
9.1.1 DESCRIPTION OF REMEDY
The selected remedy for contaminated soils is excavation and off-site disposal (Alternative 2B). This
remedy includes excavation of soils and sediments which exceed the performance standards;
dewatering sediments, if necessary; sampling of soils and sediments to determine the appropriate
disposal alternative (Subtitle C or D landfill); and transportation by truck to the landfill.
In order to facilitate this remedy, OU2 of the Marzone site is designated as an Area of Concern
(AOC) for purposes of this ROD. All waste managed within the AOC must comply with the
requirements set out in this ROD for soil remediation. OU2 and the designated AOC consists of the
former Golden Seed facility, a portion of the railroad spur drainage ditch, Gum Creek and associated
wetlands, and a portion of the Banner Grain property and Newton property adjacent to the former
Golden Seed facility. The AOC also includes suitable areas in close proximity to the contamination
necessary for implementation of the remedy selected in this ROD. Since soil contamination at OU2
will be cleaned to the risk-based performance standards, no closure standards apply for this AOC.
Major components of the soil and sediment remedy include:
1.
2.
Excavation of contaminated surface soils (0 to 1 feet) on and around the Golden Seed area
which exceed performance standards. The volume of surface soil is estimated to be 4,300
cubic yards.
On-site stockpiling surface soil for sampling to determine the appropriate disposal alternative
(Subtitle C or D landfill).
57
-------
3. Backfilling of surface soil area with sampled, clean fill and restoration of area. Restoration
will include grading and seeding.
4. Excavation of sediments, from the railroad drainage ditch beginning at the culverts at the
southernmost point of the railroad spur continuing in a northeasternly direction, which exceed
the sediment performance standards.
5. Additional sampling of non-wooded wetland area to better delineate the areas of
contamination.
6. Excavation of sediments in the non-wooded wetland area south of the railroad spur
(approximately 1,000 cubic yards) which exceed the sediment performance standards.
7. • Dewatering, if necessary, and sampling of sediments to determine the appropriate disposal
alternative (Subtitle C or D landfill).
8. Restoration of excavated wetland areas. Restoration will consist of backfilling sediments,
grading, and replanting shrubs and grasses.
9. Transportation of contaminated soil and sediment to a permitted Subtitle C or D landfill.
10. Confirmation sampling to verify that remaining soil and sediment is below performance
standards.
11. Monitoring of wetland and creek area for at least five years to determine if remaining
contamination is naturally attenuating. EPA would consider additional remedial actions, if
contamination does not appear to be naturally attenuating.
12. Air monitoring to ensure safety of nearby residents and workers.
9.1.2 PERFORMANCE STANDARDS
Performance standards for surface soil and sediments are presented in Table 9-1. The performance
standards for surface soil are based upon a 10"6 additional cancer risk level for a cleanup associated
with future residential land use or more stringent ecological risk levels. Excavation of contaminated
soils within OU2 shall continue until the remaining soil achieves the performance standards. All
excavation shall comply with ARARs, OSHA, and state standards. Pertinent testing methods will be
selected or approved by EPA and used to determine that performance standards have been achieved.
The performance standards for sediments are based on ecological models which calculate a potential
risk to ecological receptors. Contaminated sediments within the non-wooded wetland area south of
the railroad spur (Figure 9-1) will be excavated, dewatered and disposed of in a Subtitle C or D
landfill. The wetland will be restored by replacing sediment and replanting shrubs and grasses.
f
9.1.3 SOIL TESTING
" . : * • ... -
Soil testing shall be conducted on the site to determine the effectiveness of meeting the soil and
sediment performance standards outlined in Table 9-1. Performance will be met when the
confirmatory sampling effort shows surface soil (0 to 1 feet) and sediment samples from the drainage
58
-------
ditch and non-wooded wetland area south of the railroad spur have been remediated to a level at or
below the performance standards.
TABLE 9-1: SUMMARY OF SOIL AND SEDIMENT REMEDIATION
PERFORMANCE STANDARDS FOR CHEMICALS OF CONCERN
COMPOUND
DDT
DDE
ODD
Toxaphene
alpha - chlordane
gamma-chlordane
Copper
Lead
Zinc
MEDIUM
SURFACE SOIL
(MG/KG)
1.0*
1.0*
2.0*
0.4*
0.1**
0.1**
20**
330**
100**
SEDIMENT
(MG/KG) **
5.0
5.0
5.0
3.0
0.1
0.1
20
330
100
Surface soil performance standards based on protection of future residents at a 1 0* calculated cancer risk level
for direct contact
** Surface soil or sediment performance standards based on ecological risk; surface soil standards also protective
of future residents at a Kr6 calculated cancer risk level for direct contact and a Hazard Index of less than 1.0
for non-carcinogens
9.1.4 COST
For excavation and off-site disposal (Alternative 2B), the estimated present worth cost of the remedy
is approximately $1,596,874. These costs include planning and design fees, as well as mobilization
and implementation. The capital cost is approximately $1,493,082; the operation and maintenance
cost is approximately $103,792. A breakdown of estimated costs is in Table 9-3.
9.2 GROUNDWATER REMEDY
9.2.1 DESCRIPTION OF REMEDY
The selected ground water remedy is Alternative 2- monitored natural attenuation with a contingency
for an in-situ passive treatment system such as funnel-and-gate. This selected remedy is based on
groundwater data which have indicated that ground water contamination may be naturally attenuating
as it moves across the site. Natural attenuation is a combination of processes which act to reduce the
level of contamination in groundwater. These processes include biodegradation, adsorption, dilution,
and volatilization. The components of the groundwater remedy are as follows:
59
-------
3.
150'
Figure 9-1
Approximate Non-wooded Wetland Area of Contamination
Installation of at least two additional groundwater monitoring wells, one located to the west
of the Golden Seed facility and another located to the southeast of MW-02 to provide better
coverage of the groundwater contamination and its movement.
Annual groundwater monitoring for at least five years for the contaminants of concern, as
well as potential transformation products and geochemical parameters. Monitoring results
wHl be used to determine the effectiveness of natural attenuation processes such as
biodegradation, dispersion, dilution, chemical or biological stabilization, or transformation.
Review of groundwater data after five years to determine if natural attenuation is effective in
reaching performance standards. A contingency remedy of an in-situ treatment wall may be
implemented at EPA's sole discretion, if results do not confirm that natural attenuation was
effective. However, before implementing the contingency remedy, EPA may determine that
additional groundwater monitoring is necessary.
4. Institutional controls to restrict use of contaminated groundwater.
60
-------
9.2.2 PERFORMANCE STANDARDS
The performance standards for groundwater are based upon Maximum Contaminant Levels (MCLs)
established by the EPA Safe Drinking Water Act, if available. If MCLs are not available for a
contaminant of concern, performance standards are based on a 10"6 additional cancer risk level for
carcinogens or a hazard quotient of 1 or less for non-carcinogens. Pertinent testing methods will be
selected or approved by EPA and used to determine that performance standards have been achieved.
9.2.3 GROUNDWATER TESTING
Groundwater will be monitored until groundwater concentrations have met the appropriate
performance standards. After five years of monitoring, the data will be analyzed to determine if
natural attenuation processes are effective. A contingency remedy of an in-situ treatment wall may
be implemented at EPA's sole discretion, if results did not confirm that natural attenuation was
effective. Instead of implementing the contingency remedy, EPA may determine that additional
groundwater monitoring is necessary.
TABLE 9-2: SUMMARY OF GROUNDWATER REMEDIATION PERFORMANCE
STANDARDS
COMPOUND
Aluminum
Beryllium
Cadmium
Manganese
Nickel
Lead
Iron
Nitrate/Nitrite
alpha - BHC
gamma- BHC
Endrin
Dinoseb
PERFORMANCE STANDARD
(UG/L)
28,702*
4**
5**
660*
100**
15 ***
8,611*
1,000 (MCL for nitrite)
0.03 ***
0.2 **
2**
7 **
* Calculated value for Hazard Quotient = 1
** EPA Maximum Contaminant Level
*** EPA Action Level
61
-------
9.2.4 COST
For monitored natural attenuation, the estimated present worth cost of the remedy is approximately
$477,676. These costs include planning and design fees, as well as mobilization and implementation.
The capital cost is approximately $198,087; the operation and maintenance cost is approximately
$279,589. A breakdown of estimated costs is in Table 9-3.
10.0 STATUTORY DETERMINATION
Under its legal authorities, EPA's primary responsibility at Superfund sites is to undertake remedial
actions that achieve adequate protection of human health and the environment. In addition, Section
121 of CERCLA establishes several other statutory requirements and preferences. These specify that,
when complete, the selected remedial action for this Site must comply with applicable or relevant and
appropriate environmental standards established under Federal and State environmental laws. The
selected remedy also must be cost-effective and utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum extent practicable. Finally, the
statute includes a preference for remedies that employ treatment that permanently and significantly
reduce the volume, toxicity, or mobility of hazardous wastes as their principal element. The following
sections discuss how the selected remedy meets these statutory requirements.
10.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy protects human health and the environment through treating and monitoring
threats at Operable Unit 2 of the Site. The selected remedy provides protection of human health and
the environment by eliminating, reducing, and controlling risk through removal of contaminated
surface soils and sediments, monitoring of groundwater, and institutional controls. Contaminated
surface soils and sediment "hot spots" will be excavated and transported to a RCRA permitted
landfilL Groundwater and remaining contaminated sediments will be monitored to determine if
contaminant concentrations are naturally attenuating. A contingency remedy of an in-situ treatment
wall may be implemented at EPA's sole discretion, if results did not confirm that natural attenuation
was effective. Instead of implementing the contingency remedy, EPA may determine that additional
groundwater monitoring is necessary. Institutional controls will restrict the use of groundwater until
it meets groundwater performance standards.
10.2 ATTAINMENT OF THE APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS f ARARs)
Remedial actions performed under CERCLA must comply with all applicable or relevant and
appropriate requirements (ARARs). All alternatives considered for the Marzone OU2 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 all ARARs, including those listed in Tables 10-1, 10-2, 10-3,
and 10-4.
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 are necessary
with respect to the selected remedy.
62
-------
TABLE 9-3 - SUMMARY OF SELECTED REMEDY COSTS
Capital Costs
Soil Remedy • Capital Costs
Mobilization/demobilization
Excavation
Shipping costs
Disposal
Backfill of clean soil
Grading
Landscaping
Sheet piling for wetlands
Water removal in wetlands
Clearing, grubbing, and chipping
Wetland restoration
Subtotal - Capital costs
Fees (Contractor, Legal, Administrative)
Total Capital Costs
Contingency (25%)
Total Construction Costs
Quantity
1
6,300
358
5,250
6,300
20,100
4.15
7,500
5
0.7
0.7
Unit
LS
Cubic yard
Load
Ton
Cubic yard
Square yard
Acre
Square feet
Day
Acre
Acre
Unit Cost
$50,000
$10
$175
$50
$60
$0.16
$1,413
$12
$200
$500
$3,200
Soil Remedy - O&M Costs
Biennial Surface Water/Sediment
Sampling
Annual Surface Water/Sediment
Sampling
Confimatory sampling
Total Annual O&M Cost
Present Worth Cost
SOIL REMEDY - TOTAL COST
2/year
I/year
50
5 years
25 years
Samples
$4,500
$4,500
$500
Estimated
Installed Cost •
$ 50,000.00
$ 63,000.00
$ 62,650.00
$ 262,500.00
$ 378,000.00
$ 3,216.00
$ 5,863.95
$ 90,000.00
$ 1,000.00
$ 350.00
$ 2,240.00
$ 918,819.95
$ 275,645.99
$ 1,194,465.94
$ 298,616.48
$ 1,493,082.42
$ 45,000.00
$ 112,500.00
$ 25,000.00
$ 182,500.00
$ 103,792.00
$1,596,874.42
63
-------
TABLE 9-3 - SUMMARY OF SELECTED REMEDY COSTS (CONTINUED)
Quantity
Unit
Unit Cost
Estimated
Installed Cost
Groundwater - Capital Costs
Field Sampling and Analysis
Natural Attenuation Modeling
Micorcosm Study
Installation of Additional Wells
Subtotal - Capital costs
Fees (Contractor, Legal, Administrative)
Total Capital Costs
Contingency (25%)
Total Construction Costs
Groundwater - O&M Costs
Quarterly Groundwater Sampling
Annual Groundwater Sampling
Biennial Surface Water Sampling
Annual Surface Water Sampling
Total Annual O&M Cost
Present Worth Cost
GROUNDWATER - TOTAL COST
TOTAL REMEDIATION COST
1
1
1
2
I/year
I/year
2/year
I/year
Event
Event
Event
Wells
$29,000
$20,000
$62,900
$5,000
$ 29,000.00
$ 20,000.00
$ 62,900.00
$ 10,000.00
$ 121,900.00
$ 36,570.00
$ 158,470.00
$ 39,617.50
$ 198,087.50
5 years
25 years
5 years
25 years
.$30,000
$7400
$4,500
$4,500
$ 150,000.00
$ 187,500.00
$ 45,000.00
$ 112,500.00
$ 495,000.00
$ 279,589.00
$ 477,676.50
$ 2,074,550.00
LS - Lump sum
Notes:
1) Estimated costs are based on conceptual evaluation of the potential remedy and are subject to change based on
preliminary and final design
2) Assume that all excavated material shipped to Subtitle D landfill
3) Unit costs based on experience at OU1
4) Load assumed tobe 22 cubic yards; number ofloads includes 25% expansion factor; tonnage based on 1.5 cubic yard
(expanded) per ton.
64
-------
Other Guidance To Be rnnsirfprwi
OtherGuidanceTo 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 numbers are evaluated relative to the normally accepted point of departure risk range of lO"4 to
10.3 COST EFFECTIVENESS
Cost effectiveness is determined by comparing the cost of all alternatives being considered with their
overall effectiveness to determine whether the costs are proportional to the effectiveness achieved.
Overall effectiveness is defined by three of the five balancing criteria: long-term effectiveness, short-
term effectiveness, and reduction of toxicity, mobility, or volume through treatment. EPA evaluates
the incremental cost of each alternative as compared to the increased effectiveness of the remedy.
The selected remedy provides long-term effectiveness and reduction of toxicity, mobility, or volume
through treatment.
The estimated cost of EPA's selected remedy is $ 1,910,298. The selected remedy, Alternative 3B for
soils and Alternative 2 for groundwater, is the most cost effective alternative.
10-4 UTILIZATION OF PERMANENT SOLUTIONS TO THE MAXIMUM EXTENT
PRACTICABLE ~~
The selected remedy utilizes permanent solutions to the maximum extent practicable. Excavation and
landfill disposal of contaminated soils and sediments will provide a permanent solution for surface
soils and sediments. Monitored natural attenuation will allow natural processes to reduce
contaminant levels in the groundwater. A contingency remedy of an in-situ treatment wall may be
implemented at EPA's sole discretion, if results did not confirm that natural attenuation was effective.
Instead of implementing the contingency remedy, EPA may determine that additional groundwater
monitoring is necessary.
Alternative 2 for soils would provide long-term effectiveness and reduction of toxicity, mobility, or
volume through treatment; however, this alternative is more costly and has less short-term
effectiveness. Alternative A for each of the soil alternatives would provide greater long-term
effectiveness in removing contaminant mass, but would cause greater destruction to the ecological
habitat. Alternative 3 for groundwater would provide long-term effectiveness and reduction of
toxicity, mobility, or volume through treatment; however, this alternative is more costly.
10-5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The statutory preference for treatment will not be met, since contaminated soil and sediment will be
placed in a landfill and groundwater will be allowed to naturally attenuate. However, mobility of
contaminants in the soil and sediment will be reduced by placement in a permitted landfill Natural
attenuation will reduce groundwater concentrations and associated risks through naturally occurring
treatment processes.
65
-------
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
There arc no significant changes from the proposed plan.
66
-------
TABLE 10-1:
CONTAMINANT-SPECIFIC ARARS
Federal
Safe Drinking Water Act
National Primary Drinking
Water Standards
National Secondary Drinking
Water Standards
Maximum Contaminant Level
Goals (MCLGs)
Clean Water Act
Ambient Water Quality
Criteria
Resource Conservation and
Recovery Act (RCRA), as
amended
RCRA Groundwater
Protection
R&A
R&A
40 USC Section 300
40 CFR Part 141
40 CFR Part 143
40 CFR Part 141
33 USC Section 1251 et.
seq
40 CFR Part 131 Quality
Criteria for Water, 1976,
1980,1986
42 USC Section 6905,
6912,6924, 6925
40 CFR Part 264
Establishes maximum contaminant levels (MCLs)
which are health-based standards for public water
systems.
Establishes secondary maximum contaminant
levels (SMCLs) which are non-enforceable
guidelines for public water systems to ensure the
aesthetic quality of the water.
Establishes drinking water quality goals set at
levels of no known or anticipated adverse health
effects with an adequate margin of safety.
Requires the states to set ambient water quality
criteria (AWQC) for water quality based on use
classifications and the criteria developed under
Section 304(a) of the Clean Water Act.
Provides forgroundwater protection standards,
general monitoring requirements, and technical
requirements.
Clean Air Act
42 USC Section 7401 et.
67
-------
National Primary and
Secondary Ambient Air
Quality Standards
National Emissions Standards
for Hazardous Air Pollutants
(NESHAPs)
Solid Waste Disposal Act
(SWDA)
Land Disposal Restrictions
State
Georgia Department of
Natural Resources
Environmental Protection
Division; Water Quality
Control
Georgia Drinking Water
Regulations
Georgia Department of
Natural Resources
Environmental Protection
Division; Air Quality Control
R&A
R&A
A
A
A
R&A
seq.
40CFRPart50
40CFRPart61
42 USC Section 6901
et.seq.
40 CFR Part 268. 10-12;
40 CFR Part 268
(SubpartD)
Chapter 39 1-3-6
Chapter 391-3-5
Chapter 391-3-1
Section 02
Establishes standards for ambient air quality to
protect public health and welfare.
Provides emissions standards for hazardous air
pollutants for which no ambient air quality
standards exist.
Disposal of contaminated soil and debris resulting
from CERCLA response actions are subject to
Federal land disposal restrictions.
Establishes groundwater classifications and water
quality standards.
Regulates water systems within the state that
supply drinking water that may affect the public
health.
Establishes air quality standards.
A - Applicable
R&A- Relevant and appropriate
68
-------
TABLE 10-2:
LOCATION-SPECIFIC ARARS
Standard, Requirement, Criteria,
or Limitation
Citation
Federal
Description
Solid Waste Disposal Act (SWDA)
42 USC Section
6901 et. seq.
RCRA Location Standards
R&A
40CFRPart
264.18(b)
Establishes design, construction, operation and
maintenance standards for
treatment/storage/disposal (TCD) facilities
constructed in a 100-year floodplain.
Fish and Wildlife Conservation
Act
R&A
16 USC Part 2901
et. seq.
Requires states to identify significant habitats and
develop conservation plans for these areas.
Floodplain Management Executive
Order
R&A
Executive Order
11988;
40 CFR Part 6.302
Actions that are to occur in floodplain should
avoid adverse effects, minimize potential harm,
restore and preserve natural and beneficial value.
Protection of Wetlands Executive
Order No. 11990
R&A
40CFR6.302(a)
and Appendix A
Requires Federal agencies to avoid, to the extent
possible, the adverse impacts associated with the
destruction or loss of wetlands. Alternatives that
involve the alteration of a wetland may not be
selected unless a determination is made that no
practicable alternative exists.
Clean Water Act - Guidelines for
Specifications of Disposal Sites for
Dredged or Fill Material
R&A
40 CFR Part 230
Regulates the discharge of dredged or fill
material into U.S. waters, including wetlands to
ensure that discharges are evaluated with respect
to impact on aquatic ecosystems.
Endangered Species Act
R&A
16 USC Section
1531
Requires action to conserve endangered species
or threatened species, including consultation with
the Department of Interior.
69
-------
State
Georgia Erosion and
Sedimentation Control
Rules for Environmental Planning
Criteria
Game, and Fish
R&A
R&A
R&A
Chapter 391-3-7
Chapter 391-3-16
OCGA Section 27
Establishes requirements for obtaining a permit
before any land disturbing activities is undertaken.
Establishes criteria for the protection of
groundwater recharge areas and wetlands.
Protects endangered and threatened species.
Prohibits any activity which disturbs, mutilates, or
destroys wildlife homes.
A - Applicable
R&A- Relevant and appropriate
70
-------
TABLE 10-3: POTENTIAL ACTION-SPECIFIC ARARS
Standard, Requirement,
Criteria, or Limitation
Federal
Citation
Solid Waste Disposal Act
(SWDA)
Identification and Listing of
Hazardous Wastes
Standards Applicable to
Generators of Hazardous Waste
Standards Applicable to
Transporters of Hazardous
Waste
Standards Applicable to
Hazardous Waste Generation,
Storage, Transportation, and
Disposal Facilities
Land Disposal Restrictions
Hazardous Waste Permit
Program
Occupational Safety and
Health Act
R&A
R&A
R&A
R&A
•••m^VIBMII
A
42 USC Section
6901-6987
40 CFR Part 261
40 CFR Part 262
40 CFR Part 263
40 CFR 264
40 CFR Part
268.10-12; 40 CFR
268 (Subpart D)
40 CFR 270
20 USC Section
651-678
Description
Defines those solid wastes which are subject to
regulation as hazardous wastes under 40 CFR Parts 263-
265 and Parts 124,270. and 271.
Establishes standards for generators of hazardous waste.
Establishes standards which apply to persons
transporting hazardous waste within the U.S. if the
transportation requires a manifest under 40 CFR cart
262.
Established standards for hazardous waste treatment,
storage, and disposal facilities.
Disposal of contaminated soil and debris resulting from
CERCLA response actions are subject to Federal land
disposal restrictions.
Establishes provisions covering basic EPA permitting
requirements.
Regulates worker health and safety.
71
-------
TABLE 10-3: POTENTIAL ACTION-SPECIFIC ARARS
Standard, Requirement,
Criteria, or Limitation
Clean Air Act
National Ambient Air Quality
Standards
Hazardous Materials
Transportation Act
Hazardous Materials
Transportation Regulations
Citation
A
A
42 USC Section
7401-7642
40CFRPart50
49 USC Section
1801-1813
49 CFR Parts 107,
171-177
Description
Treatment technology standard for emissions to air from
incinerators, surface impoundments, waste piles,
landfills, and fugitive emissions.
Regulates transportation of hazardous materials.
State
Georgia Hazardous Waste
Management Act
Georgia Solid Waste
Management Rules
Georgia Air Quality Control Law
Georgia Hazardous Waste
Management Rules
A
R&A
A
A
Code of Georgia,
Title 12, Article 3,
Chapter 8
Chapter 391-3-4
Title 12, Chapter 9
Rules and
Regulations of the
State of Georgia,
Chapter 391-3-11
Institution and maintenance of a state-wide program for
the management of hazardous wastes through the
regulation of the generation, transportation, storage,
treatment, and disposal of hazardous wastes.
Siting and design requirements for disposal sites.
Air pollution control, air quality, and emissions control
standards.
Establishes the policies, procedures, requirements, and
standards to implement the Georgia Hazardous Waste
Management Act.
72
-------
A-Applicable
R & A - Relevant and appropriate
TABLE 10-4: TO-BE-CONSIDERED (TBCs) DOCUMENTS1
Document
Georgia Hazardous Site Response Act
(HSRA) and associated rules
Citation
OCGA Title 12,
Chapter 8, Article 3,
Part 2 and Chapter
391-3-19
Description
Establishes State hazardous
substance cleanup activities and
requirements
1 TBCs - To-be-considered criteria are documents which are not legally binding, but should be considered in determining the
necessary level of cleanup for protection of human health or the environment.
73
-------
-------
ATTACHMENT 1
RESPONSIVENESS SUMMARY
-------
-------
RESPONSIVENESS SUMMARY
RECORD OF DECISION AMENDMENT
MARZONE INC./CHEVRON CHEMICAL COMPANY SITE
OPERABLE UNIT TWO
TBFTON, TIFT COUNTY, GEORGIA
The U.S. Environmental Protection Agency (EPA) held a public comment period from July 31,
1998 through October 10 1998 for interested parties to give input on EPA's Amended Proposed
Plan for Remedial Action at Operable Unit Two (OU 2) of the Marzone fac./Chevron Chemical
Company (Marzone) Superfund Site in Tifton, Tift County, Georgia. EPA conducted a public
meeting on September 3, 1998, at the J.T. Reddick Middle School hi Tifton, Georgia. The
meeting presented the results of the Remedial Investigation, the Feasibility Study, and Risk
Assessment, as well as the proposed plan for remediation. The public comment period was
extended an additional 30 days, from September 10,1998 to October 10 1998 after EPA received
a request for an extension.
A responsiveness summary is required to document how EPA addressed citizen comments and
concerns about the Site, as raised during the public comment period. All comments summarized
in this document have been factored into the amended final decision of the remedial action for
OU2of the Marzone Site.
This responsiveness summary for the Marzone Site is divided into the following sections.
I. Overview - This section discusses the recommended alternative for remedial action
and the public reaction to this alternative.
n. Background on Community Involvement and Concerns - This section provides a
brief history of community interest and concerns regarding the Marzone Site.
ffl. Summary of Major Questions and Comments Received During the Public
Comment Period and EPA's Responses - This section presents comments
submitted during the public comment period and provides the responses to these
comments.
IV. Concerns to be Addressed in the Future- This section discusses community
concerns of which EPA should be aware during remedial design.
I. Overview
The remedial alternatives for Operable Unit Two were presented to the public in an Amended
Proposed Plan released on July 31,1998 and in pubfic notices in the Tifton Gazette on July 31,
1998; August 25,1998; and September 15,1998. A public meeting was held on September 3'
1998.
-------
n. Background on Community Involvement and Concerns
EPA has taken the following actions to insure that interested parties have been kept informed and
given an opportunity to provide input on activities at the Marzone Site. Through a Technical
Assistance Grant (TAG) to the community group, People Working for People, Inc., EPA has
provided information on site activities and investigation results. The TAG expended all grant
funds in May 1997. A TAG advisor has not been available since that time.
The public comment period for this amended ROD was initially announced as July 31,1998
through August 30,1998. EPA extended the comment period until September 10, 1998, because
information was not available in the Administrative Record until that date. EPA extended the
comment period an additional 30 days upon request. A public meeting was held on September 3,
1998 where representatives from EPA answered questions regarding the Site and the amended
proposed plan under consideration. The administrative record was available to the public at both
the information repository maintained at the Tifton and Tift County Library and at the EPA
Region 4 Library in Atlanta, Georgia. The notice of availability of the proposed plan and the
administrative record was published in the Tifton Gazette on July 31, 1998 and August 25, 1998.
Community concerns included the groundwater contamination, air monitoring, and traffic. A
summary of the concerns and EPA's responses follow.
in. Summary of Major Questions and Comments Received During the Public Comment
Period and EPA's Responses
1 • Comment: One commenter asked about the location of air monitors during the remedial
action.
EPAResponse: An air monitoring system will be installed and utilized during the remedial
activities at the Site. The specific locations of air monitors will be determined during the
remedial design phase and will depend on local wind patterns.
2. Cpmment: One commenter was concerned about the possibility of trucks not following the
proposed route which does not pass through the residential area.
EPA Response: The truck traffic will be carefully monitored to ensure that all trucks are
following the approved route. Truckers who do not follow the approved route will not be
allowed to continue working at the she. A toll-free number will be available for residents
to use, if they have concerns about the truck traffic.
3- Comment: One commenter asked if EPA had determined where dinoseb in the
groundwater is coming from and wfll EPA be doing more testing. The Commenter also
wondered if the dinoseb is part of Operable Unit 1 (OU1) or OU2.
-------
EPA Response: EPA conducted additional testing in the area where dinoseb was
discovered. The source of the dinoseb is still unknown; however, the concentrations of
dinoseb are decreasing apparently due to natural attenuation. The dinoseb is a part of
OU2; it was not found on OU1.
4- Comment: One commenter asked about the location of the groundwater plume discussed
in the Remedial Investigation Report. The commenter also asked if dinoseb was in the
groundwater plume and what other contaminants were in the plume.
EPA Response: The Remedial Investigation Report and Feasibility (RI/FS) Study Report
were amended with an errata sheet to remove the statements regarding a groundwater
plume between OU1 and OU2. Since EPA issued the RI/FS report, EPA has gathered
additional groundwater data. This data indicate that some of the groundwater
contamination may originate in OU1. Additional groundwater contamination may
originate in the area of the Golden Seed buildings and move toward the south. The
contaminants which appear consistently in the groundwater around the buildings are
metals, alpha-BHC, gamma-BHC, and endrin. Dinoseb was not found in any groundwater
samples at OU1. High concentrations of dinoseb were found in a well (MW-2) in the
northeast portion of OU2. The dinoseb contamination at OU2 is probably moving to the
south or southeast. Wells to the southwest of MW-2 do not show high levels of dinoseb
contamination. The dinoseb movement will be better defined during the Remedial Design
phase.
5. Comment: One commenter asked if testing had been conducted upstream from the creek
which flows south of the Golden Seed facility.
EPA Response: EPA has conducted extensive testing of this area with the South Tift Area
Initiative and the Remedial Investigations for the Marzone site. Available data do not
indicate that unacceptable levels of contamination exist upstream of the Site (west of
WhiddonRoad).
6. Comment: One commenter asked who would be checking the monitored natural
attenuation system for groundwater.
EPA Response: EPA will be responsible for the accuracy of the monitored attenuation
data, whether collected by EPA or some other party under EPA oversight.
7. Comment: One commenter supported the remedy selection for the railroad drainage ditch,
but stated that the aerial extent to be remediated should be validated with current sampling
analysis.
EPA Response: Sampling and analysis of the drainage ditch from the southwest corner of
the Slack property to the culverts at the southern point of the railroad spur was conducted
-------
in fall of 1998. Results indicated that remediation of this portion of the ditch was
required. This remediation was conducted in 1998.
Sampling of the ditch from the culverts to the northeastern corner of the Golden Seed
property was conducted during the OU2 remedial investigation. This portion of the
drainage ditch will be remediated during the OU2 remedial action.
8. Comment: One commenter supported the-selected remedy for surface soils, but stated that
subsurface soils adjacent to the Golden Seed concrete pad should be sampled. The
commenter also criticized the use of immunoassays at this Site.
EPA Response: Additional subsurface soil sampling was conducted in December 1998.
The results from this sampling indicate that contamination was not present above levels of
concern.
Sampling around the concrete pad was not conducted during the March 1996 field work
because of flooding in that area. Other subsurface samples upslope from the concrete pad
were not collected because of extremely shallow groundwater levels (1 foot below land
surface).
Additional soil and subsurface sampling was not conducted prior to December 1998 for
the following reasons:
1) The EPA removal program conducted soil sampling after excavating each grid to
ensure compliance with the performance standard of 100 ppm (total pesticides). The
average of the results from this sampling is 18.6 ppm (total pesticides). Data from the
removal report indicates that the majority constituents in these samples were toxaphene,
DDT, DDE, and DDD which are not contaminants of concern (COCs) in the
groundwater.
2) In comparing the groundwater COCs with surface and subsurface soil COCs, only two
organic contaminants correlate. The contaminants, endrin and endrin ketone, are not
drivers in the groundwater remediation. The second round of sampling found
concentrations of endrin below the Safe Drinking Water Act Maximum Contaminant Level
(MCL). A performance standard is not available for endrin ketone, but EPA does not
believe that the concentration of endrin ketone is of concern, based on comparison with
the endrin MCL.
3) The highest metals concentrations were only found in well MW-2 which is most likely
not influenced by activities around the concrete pad, since groundwater flow would not
proceed from the pad area to well MW-2.
-------
Immunoassays were used as a screening tool for toxaphene, DDT, and gamma-BHC to
define the boundary of contamination. The technique has been used successfully at other
Superfund sites and was a useful tool at this site.
9. Comment: One commenter stated that the Kd's for subsurface contaminants of concern
(COCs) are badly overstated, which may understate COC mobility.
EPA Response: Values for Kd's may be overstated when compared to literature values.
However, this issue is not considered to be significant since the only organic contaminants
found in both soils and groundwater are endrin and endrin ketone which for endrin was
not detected above the performance standard (MCL) in the second round of sampling.
There is no MCL or other performance standards for endrin ketone; however, the highest
level of endrin ketone in groundwater was found in well MW-2 which is upgradient from
the highest soil concentration.
10- Comment: One commenter concurred with the selected remedy of monitored natural
attenuation, but disagrees with the selection of a contingency remedy at this time. The
commenter stated that analytical results for metals may not be accurate, possibly due to
suspended solids in water samples. The commenter also stated that the groundwater is
not a useable water supply because of low yield and proximity to an animal enclosure.
EPA Response: A contingency remedy is necessary for this site, since the application
of monitored natural attenuation is unproven for the Marzone OU2 contaminants of
concern. The in-situ treatment wall is considered to be the best contingency remedy given
the hydrogeology of the area. This contingency remedy is being pilot-tested at OU1 of the
Marzone site and has been successful to date at that operable unit.
Suspended solids may have been a problem for some of the groundwater samples.
However, analysis of the data shows no correlation between high turbidity (which
correlates with high suspended solids) and high metal concentrations. In fact, well MW-
02SH, which showed the highest concentrations of most inorganics cited in the Comment,
had a turbidity of 3 NTU. Such a turbidity would be associated with a low suspended
solids concentration. The spatial variability in sample concentrations is not considered to
necessarily be evidence of a suspended solids problem, since organic contaminant'
concentrations showed similar variability.
The comment regarding the groundwater not being a useable water supply is not
supported by a quantitative analysis of the aquifer at OU2 which compares the potential
well yield to the wen yield criterion established by the EPA to define a potential source of
drinking water (150 gallons per day or approximately 0.1 gallon per minute yield per
U.S.EPA, Guidelines for Ground-Water Classification under the EPA Ground-Water
Protection Strategy. 1986). The more critical concern may be the potential for metals or
-------
pesticide-contaminated groundwater to discharge to nearby surface water or wetlands.
This concern could require that the shallow groundwater contamination be addressed,
regardless of the aquifer yield.
11. Comment: One commenter supported the decision to not remediate Gum Creek because
of the greater damage which would be done to the ecosystem.
EPA Response: EPA agrees with this comment.
12. Cpmment: One commenter disagreed with the selected remedy for the non-wooded
wetland area between the railroad spur and Gum Creek (the "hot-spot" area). The
commenter believes that the remedy should be the same as that for Gum Creek. The
commenter stated that Ac selection of cleanup levels should incorporate bioavailability
and biodegradation factors, and that cleanup decisions should be based on clear
demonstrations of causal linkage between the presence of contaminants and demonsitrated
ecological stress. The commenter stated that the available data are inadequate to
determine the extent of the proposed remedial action. The commenter further stated that a
detailed costtoenefit analysis as required by EPA (1988) should be utilized to justify
sediment removal.
EPA Response: The toxicity of the chemicals detected at Marzone is well documented in
the literature. Site-specific body burdens in prey species were used to evaluate potential
exposures to higher trophic-level organisms who may consume the frogs, etc. Because of
the tendency for pesticides such as those detected at Marzone to biomagnify in the food
chain, effects are expected in these higher-trophic level organisms. Thus, for
conservatism, EPA focused the assessment on the birds and mammals that can consume
prey species from the wetland. It is not necessary to demonstrate an effect in the frog or
in the populations of the other prey species that EPA collected before reaching the
conclusion that a significant ecological risk is present. The readily visible characteristics
of the wetland, such as the apparent health of vegetation and the presence of crayfish,
insects, and frogs, does not substantiate a claim of no unacceptable risk. The lower
trophic-level organisms are not particularly sensitive to the pesticides detected at this site.
The she-specific bioavailability of contaminants detected in site soils has already been
assessed through the use of the earthworm toxicity test. The fact that all earthworms died
when exposed to Area 2 soils demonstrates the site-specific bioavailability.
A causal relationship between the presence of site COCs and the documented ecological
stress has been demonstrated using several fines of evidence, which are the measurement
endpomts described in the Ecological Risk Assessment (ERA). A population or
community evaluation would be difficult to perform for this site, because of the mobility of
higher trophic-level populations.
-------
An adequate number of samples was collected in the wetlands area to meet the stated
objectives of the investigation, which were to conduct an overall surface water and
sediment investigation and to characterize the area. Samples were collected near the
source (at and around the culvert leading from the active portion of the site) and at the
ultimate receiver (Gum Creek). Contamination was found hi both areas. Therefore, EPA
concluded that contamination exists between these areas. A more precise definition of the
area of contamination will be provided by additional sampling during the remedial design
phase. However, a conservative estimate of the area of contamination has been described
in the ROD.
The EPA document referenced by the commenter ("Guidance for Conducting Remedial
Investigations and Feasibility Studies Under CERCLA", Interim Final, October 1988)
does not require a detailed cost/benefit analysis. The guidance states that the
"presentation of differences among alternatives can be measured either qualitatively or
quantitatively, as appropriate, and should identify substantive differences (e.g., greater
short-term effectiveness concerns, greater cost, etc.). Quantitative information that was
used to assess the alternatives (e.g., specific cost estimates, time until response objectives
would be obtained, and levels of residual contamination) should be included hi these
discussions." The proposed plan and Record of Decision present the differences among
alternatives in this way and, thus, justified the selected remedy for the wetland area.
13. Comment: One commenter criticized the method for determining remediation goal
objectives (RGOs) for the wetland sediments.
EPA Response: The RGOs for the pesticides were calculated be a different approach than
those for metals because of the differing mechanisms of toxicity. Pesticides are of concern
for food chain exposure to higher trophic-level organisms, while direct toxicity as
measured by a toxicity test is a better measure of toxicity for metals (other than mercury).
Thus, RGOs for pesticides were based on food chain modeling and site-specific
bioaccumulation data, while RGOs for metals were based on toxicity test results. EPA's
approach is consistent in that EPA always uses the most sensitive endpoint for a
contaminant to develop a RGO for that contaminant.
-------
-------
ATTACHMENT 2
STATE CONCURRENCE
-------
-------
Georgia Department of Natural Resources
205 Butler Street Suite 1154. East Tower, Atlanta, Georgia 30334-4flio
l*** c mm*. CaOTiKtfoMr
OMaion
June 3d, 1999
Ms. Annie Godfrey
USEPA Region IV (4WDSSRB)
61 Forsyth Street
Atlanta, Georgia 30303
Re: Final Record of Decision
Marzone IncVChevron Chemical Company
Superfund Site. Operable Unit 2
Dear Ms. God&ey:
The Georgia Environmental Protection Division (EPD) has completed its review of the above
referaced document EPD concurs with the Environmental Protection Agency's proposed Final
Record of Decision (ROD) as written for the Marzone/Chevron Chemical Site, Operable Unit 2.
If you have any questions, please contact Norman R. Woodbum of my staff at (404) 656-7802.
.Sincerely,
Harold F. Reheis
Director
HFR:nwr
-------
-------
Reproduced by NTIS
National Technical Information Service
Springfield, VA 22161
This report was printed specifically for your order
from nearly 3 million titles available in our collection.
For economy and efficiency, NTIS does not maintain stock of its vast
collection of technical reports. Rather, most documents are printed for
each order. Documents that are not in electronic format are reproduced
from master archival copies and are the best possible reproductions
available. If you have any questions concerning this document or any
order you have placed with NTIS, please call our Customer Service
Department at (703) 605-6050.
About NTIS
NTIS collects scientific, technical, engineering, and business related
information — then organizes, maintains, and disseminates that
information in a variety of formats — from microfiche to online services.
The NTIS collection of nearly 3 million titles includes reports describing
research conducted or sponsored by federal agencies and their
contractors; statistical and business information; U.S. military
publications; multimedia/training products; computer software and
electronic databases developed by federal agencies; training tools; and
technical reports prepared by research organizations worldwide.
Approximately 100,000 new titles are added and indexed into the NTIS
collection annually.
For more information about NTIS products and services, call NTIS
at 1-800-553-NTIS (6847) or (703) 605-6000 and request the free
NTIS Products Catalog, PR-827LPG, or visit the NTIS Web site
http://www.ntis.gov.
NTIS
Your indispensable resource for government-sponsored
information—U.S. and worldwide
-------
------- |