PB96-964008
EPA/ROD/R04-96/265
June 1996
EPA Superfund
Record of Decision:
T H Agricultural and Nutrition Site,
Albany, GA
4/26/1996
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I
RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
T H AGRICULTURE & NUTRITION SITE
OPERABLE UNIT TWO
ALBANY, DOUGHERTY COUNTY, GEORGIA
PREPARED BY
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
ATLANTA, GEORGIA
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DECLARATION
Of the
RECORD OF DECISION
OPERABLE UNIT TWO
SITE NAME AND LOCATION
T H Agriculture & Nutrition Site
Albany, Dougherty County, Georgia
STATEMENT OF BASIS AND PURPOSE
This decision document (Record of Decision), presents the selected Remedial
Action for Operable Unit Two for the T H Agriculture & Nutrition (THAN)
Site, Albany, Georgia, developed in accordance with the Comprehensive
Environmental Response, Compensation and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA)
42 U.S.C. Section 9601 et sea. , and to the extent practicable, the National
Contingency Plan (NCP) 40 CFR Part 300. This decision is based on the
administrative record for the THAN site.
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 the T H
Agriculture & Nutrition site. In accordance with 40 CFR 300.430, as the
support agency, GaEPD has provided input during this process. The State of
Georgia, as represented by GaEPD, has concurred with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the THAN site,
if not addressed by implementing the response action selected in this ROD,
may present an imminent and substantial endangerment to public health,
welfare or the environment.
DESCRIPTION OF SELECTED REMEDY
This operable unit is the second of two for the Site. This alternative
requires the design and implementation of response measures which will
protect human health and the environment. The first operable unit
addressed the source of the contamination on the western parcel of the Site
as well as the principle threat of groundwater contamination across the
entire Site. The second operable unit addresses the source of the
contamination on the eastern parcel of the Site.
The major components of the selected remedy for operable unit two include:
The excavation of all soil contaminated with organics necessary to
meet performance standards.
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The staging and preconditioning of soil for low temperature thermal.
desorption treatment.
The treatment of excavated soil by low temperature thermal
desorption.
The placement of treated, decontaminated soil back to the Site.
Periodic sampling of treated soil during the treatment process to
verify the effectiveness of the remedy.
Air monitoring to ensure safety of nearby residents and workers.
Groundwater monitoring to ensure that metals contamination remaining
in the subsurface soil will not result in contaminated groundwater
migrating offsite in concentrations which exceed groundwater
protection standards. Institutional controls such as deed
restrictions to prevent residential use of groundwater were
implemented under the OU 1 remedy.
Deed restrictions to prevent residential use of the property.
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. This remedy satisfies tJa
preference for treatment that reduces toxicity, mobility, or volume as a
principal element. Finally, it is determined that this remedy utilizes a
permanent solution and alternative treatment technology to the maximum
extent practicable.
Because this remedy will result in hazardous substances remaining onsite
above health-based levels 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, ACTING DIRECTOR DATE
WASTE MANAGEMENT DIVISION
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TABLE OF CONTENTS
I'.O SITE LOCATION AND DESCRIPTION 1
2 .0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 1
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 6
4.0 SCOPE AND ROLE OF OPERABLE UNIT 6
5.0 SUMMARY OF SITE CHARACTERISTICS 7
5.1 GEOLOGY/SOILS 7
5.2 SURFACE WATER AND SEDIMENTS 7
5.3 HYDROGEOLOGY 8
5.4 NATURE AND EXTENT OF CONTAMINATION 9
6.0 SUMMARY OF OPERABLE UNIT TWO RISKS 10
6.1 CONTAMINANTS OF CONCERN 10
6.2 EXPOSURE ASSESSMENT 11
6.3 TOXICITY ASSESSMENT 14
6.4 RISK CHARACTERIZATION 14
6.5 ENVIRONMENTAL RISK 17
6.6 CLEANUP GOALS 21
7.0 DESCRIPTION OF ALTERNATIVES 23
7.1 ALTERNATIVE NO. 1 - NO ACTION 23
7.2 ALTERNATIVE NO. 2 A/B - EXCAVATION AND THERMAL
DESORPTION 24
7.3 ALTERNATIVE NO. 3 A/B - EXCAVATION AND OFFSITE DISPOSAL . . 24
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES 25
8.1 OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT . . 26
8.2 COMPLIANCE WITH ARARS 26
8.3 LONG-TERM EFFECTIVENESS AND PERMANENCE 31
8.4 REDUCTION OF TOXICITY, MOBILITY OR VOLUME THROUGH
TREATMENT 31
8.5 SHORT-TERM EFFECTIVENESS 31
8.6 IMPLEMENTABILITY 31
8.7 COST , 31
8.8 STATE ACCEPTANCE 32
8.9 COMMUNITY ACCEPTANCE 32
9.0 SUMMARY OF SELECTED REMEDY 32
9.1 SOIL REMEDY 32
9.2 PERFORMANCE STANDARDS FOR SOIL 34
9.3 SOIL TESTING 35
9.4 COST 35
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10.0 STATUTORY DETERMINATION 3^
10.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT I
10.2 ATTAINMENT OF THE APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs) 36
10.3 COST EFFECTIVENESS 36
10.4 UTILIZATION OF PERMANENT SOLUTIONS TO THE MAXIMUM EXTENT
PRACTICABLE 36
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT 37
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES 37
APPENDIX A - RESPONSIVENESS SUMMARY 38
LIST OF TABLES
TABLE 1 GEOLOGIC AND HYDROGEOLOGIC EQUIVALENTS, ALBANY AREA 8
TABLE 2 CONTAMINANTS OF POTENTIAL CONCERN 12
TABLE 3 CRITICAL TOXICITY VALUES (SLOPE FACTORS) 15
TABLE 4 CRITICAL TOXICITY VALUES (REFERENCE DOSES) 16
TABLE 5 SUMMARY OF RISKS FOR CURRENT USE SCENARIO 18
TABLE 6 SUMMARY OF RISKS FOR FUTURE USE SCENARIO . .
TABLE 7 SUMMARY OF CUMULATIVE POTENTIAL RISKS 20
TABLE 8 SUMMARY OF REMEDIAL ACTION OBJECTIVES 22
TABLE 9 OPERABLE UNIT #2 ALTERNATIVES 24
TABLE 10 POTENTIAL CONTAMINANT SPECIFIC ARARS "87
TABLE 11 POTENTIAL LOCATION SPECIFIC ARARS 28
TABLE 12 POTENTIAL ACTION SPECIFIC ARARS 29
TABLE 13 TO-BE-CONSIDERED (TBCs) DOCUMENTS 31
TABLE 14 SUMMARY OF REMEDIAL ACTION OBJECTIVES 35
LIST OF FIGURES
FIGURE 1 AREA MAP FOR ALBANY, GEORGIA 4
FIGURE 2 SITE MAP FOR THE T H AGRICULTURE & NUTRITION SITE : .
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Decision Summary
Record of Decision
Operable Unit Two
T H Agriculture & Nutrition Site
Albany, Georgia
1.0 SITE LOCATION AND DESCRIPTION
The T H Agriculture & Nutrition (THAN) Site (hereinafter, "the Site") is
located at 1401 and 1359 Schley Avenue in Albany, Georgia. For an area
location map and general Site map, see Figures 1 and 2, respectively. The
Site consists of two former pesticide formulation facilities where various
liquid and dry formulations of pesticides and other chemical compounds were
handled for approximately thirty years. Current owners of the two
properties are T H Agriculture & Nutrition Company, Incorporated ("the
western parcel" or "THAN property") and Mr. Larry Jones ("the eastern
parcel" or "Jones property").- The Jones property contains an active
welding supply store. This parcel (1359 Schley Avenue) consists of
approximately five acres, with several structures remaining in the central
portion of the property. The Site is bordered on the east by residences
and a small U.S. Department of Agriculture laboratory, on the south by
Schley Avenue, on the west by a Seaboard Coastline Railway line, and on the
north by a construction company and by property owned by Albany Motel
Limited. To the west and southwest are lightly populated residential
areas. Several motels are within a one mile radius of the Site, with the
closest being located northeast of the Site. Located approximately 300
feet south of the Site is an elevated expressway and further south, a large
commercial section of Albany.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
The THAN Property, or western parcel, was used as a formulation and
packaging plant for agricultural chemicals from the 1950's until 1982. It
appears that the handling of agricultural chemicals commenced at the THAN
Property while it was owned by Walker Fertilizer Company, from 1956 to
1958. Pesticide formulation operations were then conducted by a succession
of owners until business operations at the THAN Property ceased in 1982.
Pesticides handled at the THAN Property include lindane, DDT, toxaphene,
methyl parathion, malathion, and parathion. All of these pesticides are
CERCLA hazardous substances. Dry pesticides were formulated on the THAN
Property during the 1960s and 1970s (and possibly during the 1950s).
Liquid pesticides were formulated on the THAN Property from approximately
1973 until approximately 1978. During liquid formulation operations, the
blending tank was rinsed between batches with xylene, which was then
discharged into a drainage ditch on the property. Wettable powder began
replacing liquid pesticides in approximately 1976. Very little pesticide
formulating took place after 1978. Business operations on the THAN
Property ceased in 1982.
The eastern parcel, or Jones Property, has a similar history. The Jones-
Property was used as a formulation and packaging plant for agricultural
chemicals from 1964 into the 1970s. It appears that the handling of
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agricultural chemicals commenced at the Jones Property when it was
purchased by Southeastern Liquid Fertilizer Company, Inc., in 1964.
Pesticide formulation operations (dry and liquid) were then conducted by
succession of owners. In 1973, the Jones Property was purchased by Gold
Kist, Inc., which did not engage in pesticide formulation activities on the
property, but continued fertilizer blending and fertilizer and pesticide
retail sales until 1981. In 1985, Gold Kist sold the eastern parcel to the
current owner, Mr. Larry Jones, who operates a welding supply store on the
property.
THAN conducted a removal on the THAN Property in 1984 to remove surficial
soils in accordance with a cleanup plan approved by the Environmental
Protection Division of the Georgia Department of Natural Resources (EPD).
The EPD-approved clean-up plan provided for the removal of identified areas
of soil contamination exceeding clean-up criteria established by EPD.
Removal activities conducted with EPD oversight included demolition of
several buildings, excavation of selected surface soils and subsurface
disposal areas, installation of a perimeter fence, and establishment of a
vegetative cover. Excavated soils and debris were disposed off-site in a
permitted hazardous waste landfill.
The Site was listed on the National Priorities List (NPL) on March 31,
1989. The original listing was based solely on the release of hazardous
substances from the THAN Property. THAN agreed to conduct the Remedial
Investigation/Feasibility Study (RI/FS) pursuant to an Administrative Order
By Consent dated July 6, 1990. In the course of the Remedial
Investigation, sampling on the Jones Property established that the
groundwater contamination plume extends underneath the Jones Property and*
that there is significant source contamination on the Jones Property. EPA
divided the Site into Operable Units: Operable Unit 1 addresses soil
contamination on the THAN Property (western parcel) and groundwater
contamination for the entire Site. Operable Unit 2 addresses soil
contamination on the Jones Property or eastern parcel of the Site.
A second removal was conducted at the THAN Property pursuant to a
Unilateral Administrative Order (UAO) issued to THAN by EPA in March of
1992. The second removal was initially proposed to EPA by THAN while THAN
was conducting the RI/FS for Operable Unit 1 at the Site. EPA's Emergency
Response Branch evaluated THAN's proposal and determined that a removal was
warranted in light of the discovery during the RI/FS of a disposal pit
containing pure product and high concentrations of contamination under the
former wet mix building on the THAN Property. THAN refused to sign a
removal consent order because THAN did not agree with EPA's subsurface soil
action levels. Accordingly, EPA issued a UAO for the removal on the THAN
Property.
Pursuant to the UAO, THAN 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 100 ppm for total
pesticides. Over 24,700 tons of soil.were removed and shipped to a
permitted hazardous waste landfill. THAN conducted on-site thermal
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desorption of approximately 3,000 tons of excavated soil which could not be
landfilled because it contained greater than 1,000 ppm of total pesticides.
The UAO also required THAN to backfill excavated areas and place a uniform
engineered clay cover over the removal area.
P6st-removal confirmation samples show that levels of contamination in the
soil on the THAN Property have been reduced from greater than 1,000 ppm
total pesticides in some locations to levels of less than 25 ppm total
pesticides. The top foot of soil was removed at approximately six of the
seven acres on the THAN Property, with specific areas being excavated to
seven feet below the surface.
EPA issued a ROD for Operable Unit 1 on May 21, 1993, which called for (1)
no further action with respect to soils on the THAN property because the
removal had adequately addressed contaminated soil on that property, and
(2) pumping and treating of contaminated groundwater beneath the entire
Site, including the Jones and THAN properties. THAN is conducting the
RD/RA pursuant to a UAO; the UAO was also issued to THAN's parent company,
North American Phillips Corporation, which refused to comply with the
Order. A UAO was also issued to four PRPs connected to the Jones Property,
Boise Cascade Corporation, Air Products and Chemicals, Inc., Hercules,
Inc., and Gold Kist, Inc., directing them to participate in the Operable
Unit 1 clean-up.
Special Notice letters were sent to potentially responsible parties (PRPs)
connected with the eastern parcel or Jones Property in July of 1992, to
commence negotiations for a consent order providing for PRPs to conduct the
Operable Unit 2 RI/FS. None of the PRPs connected to the Jones Property
were .willing to conduct the Operable Unit 2 RI/FS, so EPA conducted the
study.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
An availability session at a local library and community interviews with
local officials were held at the start of field work for the RI for
operable unit one on December 12, 1990. The main branch of the Dougherty
Public Library at 300 Pine Street was chosen as the local information
repository for the Site. On March 12, 1992, THAN held a public meeting to
discuss the second removal action at the Site. In addition, a fact sheet
concerning the RI for operable unit one was sent to .the mailing list in May
1992.
The public comment period on the proposed plan for the operable unit one
ROD was September 14, 1992 through November 14, 1992. A public meeting was
held on Thursday, September 24, 1992 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 repository maintained at the Dougherty Public Library and at
the EPA Region IV Library at 345 Courtland Street in Atlanta, Georgia. The
notice of availability of these two documents was published in the Albany
News-Herald on September 10, 1992. Responses to the significant comments
received during the public comment period and at the public meeting were
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included in the Responsiveness Summary, which was part of the ROD for
operable unit one.
The public comment period on the proposed plan for this ROD (operable unit
two) was January 31, 1996 through April 1, 1996. EPA published notice that
it would hold a public meeting upon request of the community. However, a
public meeting was not requested by the public. The administrative record
was available to the public at both the information repository maintained
at the Dougherty Public Library and at the EPA Region IV Library at 345
Courtland Street in Atlanta, Georgia. The notice of availability of these
documents was published in the Albany News-Herald on January 31, 1996 and
February 3, 1996, in the Southwest Georgian on February 1, 1996, and in the
Albany Journal on February 9, 1996. Notice of the extension of the comment
period was published in the Albany News-Herald on February 29, 1996 and
March 4, 1996. Responses to the significant comments received during the
public comment period are included in the Responsiveness Summary which is
part of this ROD (Appendix A) .
This decision document presents the selected remedial action for operable
unit two of the THAN site, chosen in accordance with CERCLA, as amended by
SARA, and the NCP. The decision for this Site is based on the
administrative record. The requirements under Section 117 of CERCLA/SARA
for public and state participation have been met for this operable unit,.
4.0 SCOPE AND ROLE OF OPERABLE UNIT
EPA has organized the work at this Superfund Site into two operable units
(OUs). These units are:
OU one: Contamination in the residuum and the upper Ocala aquifers
underneath the entire Site and contamination of soils on the western
portion (THAN property) of the Site.
OU two: Contamination of the soils on the eastern portion (Jones
property) of the Site.
OU #1 addressed both the source of groundwater contamination in the soils
on the western parcel as well as the groundwater contamination underneath
the entire Site. The non-aqueous phase liquid (NAPL) plume was also
addressed in OU #1. The purpose of operable unit one was to initiate
groundwater restoration, collect data on aquifer response to remediation,
prevent current or future exposure to the contaminated soils, and reduce
contaminant migration into the groundwater.
Operable unit two addresses the source of contamination on the eastern
parcel of the site. This Site was divided into two operable units after
the RI report showed that continuous groundwater contamination is present
under both properties, and that source areas exist on the eastern parcel
which needed to be investigated further. Additional Potentially
Responsible Parties (PRPs) are involved on the eastern parcel since that
property was owned and operated separately from the western parcel.
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5.0 SUMMARY OF SITE CHARACTERISTICS
5.1 GEOLOGY/SOILS
The sedimentary units outcropping in Dougherty County range from Quaternary
to Cretaceous in age. Only the uppermost geologic units consisting of the
Residuum, the Ocala Limestone, the Claiborne Group, and the Wilcox Group
are pertinent to this study. The Residuum is typically a silty clay with
minor varying amounts of sand, limestone fragments, and lignite. It has an
average thickness onsite of approximately 26 feet and thickens to the
northwest. The lithology and structure of the deposit is influenced
primarily by the amount of weathering and the effect of precipitation on
the highly soluble limestone. The Residuum overlies the Ocala Limestone.
The Ocala consists of medium to fine-grained highly weathered,
fossiliferous limestone with some silt and sand. The surface of the
limestone gently undulates and contains depressions, typical of karst
terrains. The limestone grades from a highly weathered material at the top
of the formation to a more brittle rock approximately 30 feet (about 60
feet below ground surface) into the formation. Table 1 provides
information concerning the generalized stratigraphy.
5.2 SURFACE WATER AND SEDIMENTS
The area surrounding the Site is drained by the Flint River and
Kinchafoonee Creek systems. Kinchafoonee Creek, located approximately 0.4
miles to the east of the THAN site is the nearest natural body of surface
water. However, there are no swales, drainage ditches, or intermittent
streams that drain from the Site directly to surface waters.
Drainage from the central and eastern portion of the site drains into a
culvert which flows beneath Schley Avenue. This culvert drains to a small
holding pond immediately south of the Liberty Expressway. An outlet for
this pond was not located.
Drainage from the western portion of the Site enters a curb inlet on Schley
Avenue and flows into a ditch south of Schley Avenue. From this point th*
storm water flows west through a culvert beneath the Georgia-Great Southern
railroad tracks and into a depression south of the Liberty Expressway.
Runoff from the Interstate Truck Leasing facility which is south of the
depression also flows into this depression. The depression drains into the
storm sewer system beneath Palmyra Road through an inlet at the west end.
The storm system beneath Palmyra Road flows one-half mile southeast, then
turns east and flows one-half mile beneath Stuart Avenue, and eventually
discharges into a large stormwater holding pond south of the Liberty
Expressway ( southeast of the Site). The holding pond drains through an
outlet which flows beneath Liberty Expressway and discharges into
Kinchafoonee Creek one-quarter mile to the northeast.
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Table 1
Geologic and Hydrogeologic Equivalents, Albany Area
Approximate
Thickness
(Feet)
15-50
175
230
120
180
80
300
Geologic Sequence
Group
Formation
Residuum
Ocala
Claiborne
Wilcox
Midway
Lisbon
Tallahatta
Hatchetigbee
Tuscahoma
Clayton
Providence Sand
Ripley
Hydrogeologic
Sequence
Upper water-
bearing
Floridan
Aquifer
Clayton
Aquifer
Providence
Sand Aquifer
Confining Unit
5.3
HYDROGEOLOGY
The shallow groundwater system is contained in the residuum soils and the
upper portion of the Ocala Limestone. Infiltration of rainfall runoff
through the surface sands and residuum materials is the major source of
recharge to the aquifers. Typically, the groundwater reservoirs are
recharged most during the winter and spring months when precipitation is
high and evapotranspiration is low. Conversely, little recharge is added
to the groundwater system during the dry summer months in which heavy
agricultural pumpage causes regional drawdowns in the water level
elevations. Recharge rates are directly affected by the transmissivity and
thickness of the overburden residuum.
Shallow water levels have been observed to rise more than 10 feet within
hours of any intense rainfall event. The magnitude of the rise in water
levels are unexpected since the Site is overlain by a low permeability clay
layer similar to a "cap." The magnitude of the response is also unexpected
since the volume of water infiltrating through this layer (cap) is very
low. The increase in water levels are due to a hydraulic pressure increase
transmitted laterally throughout the residuum and weathered Ocala from
runoff infiltrating more permeable sediments in topographically low areas
where ponding of surface water temporarily occurs.
This Site has several unique hydrogeologic features. First, it is unusual
for a very low permeability clay which effectively inhibits surface
recharge to exist at land surface in the Dougherty Plains. Nevertheless,
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recharge occurs through numerous depressions which transmit water rapidly
to a lower more transmissive unit (lower Floridan). Secondly, although the
total porosity of the Residuum and upper Floridan Aquifer is high (30-50
percent), very little "drainage" of water (probably less than 5 percent) of
these units takes place during drought periods.
A comparison of piezometric maps before and after a heavy rainfall event
may suggest that the storage in the aquifer "has been filled," which causes
an increase in the gradient and suggests that water is freely flowing.
However, this is not the case. Based on the number of laboratory
permeability tests and slug tests conducted within the upper 30 feet of
Residuum and limestone, the actual physical movement of water (vertically
or horizontally) is not significant. Except for the existence of some
paths of preferential groundwater flow in the more brittle and permeable
sections of the limestone, the volume of water moving laterally through the
Site is relatively small.
Solution features such as joints, fractures, and solution channels are
generally not present in the shallow aquifer. Based on the slug tests and
aquifer pumping tests conducted onsite, there appears to be "channels" of
preferred groundwater flow in the weathered upper Floridan aquifer. These
channels are formed by unequal weathering of the limestone. Most of the
upper Floridan is very fine grained and appears in large "islands" of low
permeability separated by the more permeable channels. Most wells are
screened into the islands; however, wells located near or in the channels
will often have a much greater ability to produce water.
5.4 NATURE AND EXTENT OF CONTAMINATION
The primary organochlorine (OC) pesticides detected in soil on the eastern
parcel include: toxaphene, 4,4'-DDT and its metabolites, and endrin. The
analytical results for the surface and subsurface soil samples indicated
that generally the surface soils have the highest concentrations of the OC
pesticides and that the concentrations decrease significantly with depth.
However, the highest concentration of toxaphene was found at a depth of
five feet. The physical/chemical nature of the OC pesticides suggests that
they are not readily biodegraded in the surface environment. The OC
pesticides are generally not soluble in water. However, they are
significantly more soluble in organic solvents, such as xylene. The OC
pesticides also have more affinity for organic matter in soils, which is
generally highest in concentration in the upper limits of the vadose zone.
The presence of the OC pesticides and their relatively high concentrations
in the surface soils attest to their relative immobility and non-
biodegradability.
Organophosphorus (OP) pesticides are essentially absent from surface and
subsurface soil samples. The OP pesticides were detected in only three
subsurface soil samples.
The major herbicide detected on the eastern parcel was 2,4-D. The highest
concentration of this compound was detected in a subsurface soil sample.
Like the OC pesticides, the concentrations generally decreased with depth.
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The frequency of detection of these compounds was low and somewhat
localized. The herbicides are also similar to the OC pesticides in theirj
stability and immobility in soil. They are, however, more mobile in the
presence of organic solvents.
Volatile and semivolatile organic compounds were generally found in
subsurface soil samples on the eastern property, albeit infrequently and at
low concentrations. Volatile organic compounds were not detected in most
of the surface soil samples since these contaminants are readily
volatilized or biodegraded.
Elevated levels of metals were found throughout the eastern property.
Levels of aluminum, arsenic, chromium VI, iron, and vanadium were detected
in surface soils at levels significantly above background levels. In
subsurface soils, beryllium, cadmium, lead and manganese were detected at
elevated levels. In previous investigations, these metals also were
detected in groundwater samples below the eastern property at levels above
Maximum Contaminant Levels or health-based concentrations.
OC pesticides such as DDT and toxaphene were detected in the sediment
samples both on- and off-site. However, the concentrations of the
pesticides generally dropped significantly in the off-site collection
locations as compared to the onsite collections. As expected, the
pesticides are bound to the sediments rather than to the surface water,
since the water samples collected in the depression and holding pond south
of the Liberty Expressway did not detect any contamination by pesticides.
Surface water samples were contaminated with 2,4-D and atrazine.
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 and
subsurface soil pose a potential risk.
The major risk currently associated with OU2 of the THAN Site is the
ingestion and dermal contact of contaminated soil. In addition, the
migration of subsurface contaminants into the groundwater would pose a risk
for potential users of the groundwater. Surface water and sediment
contamination did not pose a significant 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 CONTAMINANTS OF CONCERN
The majority of the wastes and residues generated by production operations
at the facility have .been managed, treated, and disposed of onsite
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throughout the Site's history. The chemicals measured in the various
environmental media during the RI were evaluated for inclusion as chemicals
of potential concern in the risk assessment by application of screening
criteria. The criteria which resulted in elimination of chemicals
included: inorganics whose maximum concentration did not exceed two times
the average background concentration and inorganics that are essential
nutrients or are normal components of human diets. Table 2 lists the
chemicals of potential concern for the Site.
6.2 EXPOSURE ASSESSMENT
Whether a chemical is actually a concern to human health and the
environment depends upon the likelihood of exposure, i.e. whether the
exposure pathway is currently complete or could be complete in the future.
A complete exposure pathway (a sequence of events leading to contact with a
chemical) is defined by the following four elements:
A source and mechanism of release from the source,
A transport medium (e.g., surface water, 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.
The current pathways are:
potential oral exposure by on-site workers to on-site surface
soils,
potential oral exposure by visitors to on-site surface soils
and off-site drainage ditch soils and pond/depression
sediments,
potential oral exposure by visitors to off-site surface water,
potential dermal exposure by on-site workers to on-site surface
soils,
11
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Table 2
Contaminants of Potential Concern
Aluminum
Arsenic
Beryllium
Cadmium
Chromium VI
Iron
Lead
Manganese
Vanadium
Atrazine
Benzo(a)pyrene
Benzo(b)
fluoranthene
Indeno(l,2,3)
pyrene
Dieldrin
4, 4 '-DDT
4, 4 '-DDE
4, 4 '-ODD
Endrin
Ethylene dibromide (EDB)
Methyl carathion
Toxaphene
Surface Soil
Maximum
(mq/kq)
23,000
8.9
0.91
6.7
110
48,000
200
4,600
78
1.30
1.30
0.92
0.44
390
26
13
- 40
1,500
RME *
(mq/kq)
10,148
4.6
0.5
1.8
28.4
27,052
22.9
452
53.6
0.3
0.03
0.03
0.4
390
11
13
12.5
1,500
Subsurface
soil
(mg/kg)
121,000
53
40
23
64
110,000
620
9,200
270
0.44
210
4.1
19
13
0.87
69
1,800
Sediment
(mg/kg)
2.3
35.000
31
380
190
Surface Water
(ug/L)
310
8.9
* = Reasonable maximum exposure (Upper Confidence Limit or maximum when UCL is greater than maximum
12
-------
potential dermal exposure by visitors to on-site and off-site
drainage ditch soils and pond/depression sediments ,
potential dermal exposure by visitors to off-site surface
water, and
potential inhalation exposure by workers and visitors to dust.
The future pathways are:
potential dermal exposure by residents to surface soil,
potential oral exposure by residents to surface soil,
potential inhalation exposure by residents to dust, and
potential ingestion of groundwater from a future drinking water
well.
The exposure point concentrations for each of the chemicals of concern and
the exposure assumptions for each pathway were used to estimate the
chronic daily intakes for the potentially complete pathways, with the
exception of the groundwater pathway. The chronic daily intakes were then
used in conjunction with cancer potency factors and noncarcinogenic
reference doses to evaluate risk.
The major assumptions about exposure frequency and duration that were
included in the exposure assessment were:
Future onsite residents were assumed to have an exposure
frequency of 350 days per year. The industrial worker is
assumed to spend 250 days per year onsite for 25 years, based
on a 5 day working week for 50 weeks per year. A 7-16 year-old
juvenile visitor who would enter the Site is assumed to have an
exposure frequency of 24 days per year for 10 years. The
juvenile visitor is assumed to visit the depression and surge
pond 36 times per year for 10 years.
Soil ingestion rates for future onsite residents include a rate
of 200 mg/day for children and 100 mg/day for adults. Soil
ingestion rates for current use are 50 mg/day for an industrial
worker and 100 mg/visit for a juvenile visitor. The surface
water ingestion rate is 20 ml/day for a visitor wading in the
depression or surge pond. The sediment ingestion rate is 100
mg per visit.
Dermal contact exposure parameters for surface water for a
juvenile visitor include contact 4 times/month for 9
months/year or 36 visits/year for 10 years.
In all scenarios a standard body weight of 70 kg was used for
adults and 45 kg was used for juveniles.
13
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6.3 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 numerous toxicity 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 3 presents
cancer slope factors for the potential chemicals of concern.
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 in adverse
health effects, even for the most sensitive members of the population.
Table 4 presents reference doses for the potential chemicals of concern.
6.4 RISK CHARACTERIZATION
Human health risks are characterized for potential carcinogenic and non-
carcinogenic effects by combining exposure and toxicity information.
Excessive lifetime cancer risks are determined by multiplying the
estimated daily intake level with the cancer potency factor. These risks
are probabilities that are generally expressed in scientific notation
(e.g., IxlO'6). An excess lifetime cancer risk of IxlO'6 indicates that,
as a plausible upper boundary , an individual has a one in one million
additional (above their normal risk) chance of- developing cancer as a
14
-------
TABLE 3
CRITICAL TOXICITY VALUES1
SLOPE FACTORS (SFs)
Compound
Aluminum
Arsenic
Beryllium
Cadmium
Chromium VI
Iron
Lead
Manganese
Vanadium
Atrazine
Benzo (a)pyrene
Benzo (b) f luoranthene
Indeno (1,2,3) pyrene
Dieldrin
4,4' -DDT
4, 4 '-DDE
4,4' -ODD
Endrin
Toxaphene
Cancer Slope Factor
CSFo
NA
1.75E+00
4.3E+00
NA
NA
NA
NA
NA
NA
2.2E-01
7.3E+00
7.3E+00
7.3E+00
1.6E+01
3.4E-01
3.4E-01
2.4E-01
NA
1.1E+00
CSFi
NA
1.5E+01
8.4E+00
6.3E+00
4.2E+01
NA
NA
NA
NA
NA
3.1E+00
NA
NA
1.6E+01
3.4E-01
NA
NA
NA
1.1E+00
CSFd
NA
8 . 8E+00
2.2E+U1
NA
NA
NA
NA
NA
NA
4.4E-01
1.5E+01
1.5E+01
1.5E+01
3.2E+01
6.8E-01
6.8E-01
4.8E-01
NA
2.2E+00
Notes;
1 Critical toxicity values obtained from Integrated Risk Information
System (IRIS) or Health Effects Assessment Summary Tables (HEAST)
(USEPA, Fiscal Year 1991).
CSFo - Cancer Slope Factor (Oral), (mg/kg/day) -1
CSFi - Cancer Slope Factor (Inhalation), (mg/kg/day)'1
CSFd - Cancer Slope Factor (Dermal), (mg/kg/day)"1; derived by converting
the oral CSF to an absorbed dose value
NA - Not Applicable (No data)
15
-------
TABLE 4
CRITICAL TOXICITY VALUES1
REFERENCE DOSES (RfDs)
Compound
Aluminum
Arsenic
Beryllium
Cadmium (water)
Cadmium (food)
Chromium VI
Iron
Lead
Manganese (water)
Manganese (food)
Vanadium
Atrazine
Benzo (a) pyrene
Benzo (b) f luoranthene
Indeno (1,2,3) pyrene
Dieldrin
4,4' -DDT
4, 4 '-DDE
4,4' -ODD
Endrin
Toxaphene
Reference Doses
RfDo
1E+00
3E-04
5E-03
5E-04
1E-03
5E-03
3E-01
NA
5E-03
1.4E-01
7E-03
3.5E-02
NA
NA
NA
5E-05
5E-04
5E-04
5E-04
3E-04
NA
RfDd
2E-01
6E-05
1E-03
1E-04
2E-04
1E-03
6E-02
NA
1E-03
3E-02
1E-03
2E-02
NA
NA
NA
3E-05
3E-04
3E-04
3E-04
2E-04
NA
Notes :
1 Critical toxicity values obtained from Integrated Risk Information
System (IRIS) or Health Effects Assessment Summary Tables (HEAST)
(USEPA, Fiscal Year 1991).
RfDo - Reference Dose (Oral), mg/kg/day
RfDd - Reference Dose (Dermal), mg/kg/day; derived by
converting the oral RfD to an absorbed dose value
NA - Not Applicable (No data)
16
-------
result of site-related exposure to a carcinogen over a 70-year lifetime
under the assumed specific exposure conditions at a site.
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 THAN Site.
EPA considers individual excess cancer risks in the range of IxlO'4 to
IxlO'5 as protective; however the IxlO'6 risk level is generally used as the
point of departure for setting cleanup levels at Superfund sites. The
point of departure risk level of IxlO"6 expresses EPA's preference for
remedial actions that result in risks at the more protective end of the
risk range. The estimated health risks for OU #2 are shown in Tables 5, 6,
and 7.
Potential concern for noncarcinogenic effects of a single contaminant in a
single medium is expressed as the hazard quotient (HQ) (or the ratio of the
estimated intake derived from the contaminant concentration in a given
medium to the contaminant's reference dose). A HQ which exceeds one (1)
indicates that the daily intake from a scenario exceeds the chemical's
reference dose. By adding the HQs for all contaminants within a medium or
across all media to which a given population may reasonably be exposed, the
Hazard Index (HI) can be generated. The HI provides a useful reference
point for gauging the potential significance of multiple contaminant
exposures within a single medium or across media. An HI which exceeds
unity indicates that there may be a concern for potential health effects
resulting from the cumulative exposure to multiple contaminants within a
single medium or across media. The His for OU #2 are shown in Tables 5, 6
and 7 .
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.
6.5 ENVIRONMENTAL RISK
The Site is located in a light industrial area in the city limits of
Albany, Georgia, primarily surrounded by industrial facilities. Natural,
vegetative covers, such as pine woods, have been fragmented due to
industrial and highway development. Surface water bodies near the site
consist of two areas (a depression and a surge pond) which receive surface
17
-------
TABLE 5
SUMMARY OF CANCER RISKS
AND NON-CANCER RISKS BY EXPOSURE ROUTE
CURRENT USE SCENARIO
Location
Site
Surface
Soil
Drainage-
Ditch Soil
DOT Surge
Pond Water
DOT Surge
Pond
Sediment
Depression
Area Water
Depression
Area
Sediment
Exposure
Route
Inadvertent
Ingestion
Dermal Contact
Inhalation of Dust
Inadvertent
Ingestion
Dermal Contact
Inhalation of Dust
Inadvertent
Ingestion
Dermal Contact
Inadvertent
Ingestion
Dermal Contact
Inadvertent
Ingestion
Dermal Contact
Inadvertent
Ingestion
Dermal Contact
TOTAL CURRENT RISK
On-Site Worker
Cancer
3E-04
2E-04
5E-08
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
6E-04
HI
0.5
0.4
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.9
Site Visitor
Cancer
4E-05
2E-05
2E-09
2E-05
IE-OS
2E-11
NA
NA
NA
NA
NA
NA
NA
NA
9E-05
HI
0.1
0.1
NA
0.1
0.03
NA
0.0002
0.0002
0.01
0.002
0.003
0.004
0.03
0.004
0.4
NA - Not applicable
18
-------
TABLE 6
SUMMARY OF CANCER RISKS
AND NON-CANCER RISKS BY EXPOSURE ROUTE
FUTURE USE SCENARIO
Location
Site
Surface
Soil
Drainage
Ditch Soil
DOT Surge
Pond Water
DOT Surge
Pond
Sediment
Depression
Area Water
Depression
Area
Sediment
Exposure
Route
Inadvertent
Ingestion
Dermal Contact
Inhalation of
Dust
Inadvertent
Ingestion
Dermal Contact
Inhalation of
Dust
Inadvertent
Ingestion
Dermal- Contact
Inadvertent
Ingestion
Dermal Contact
Inadvertent
Ingestion
Dermal Contact
Inadvertent
Ingestion
Dermal Contact
TOTAL FUTURE RISK
Child Resident
Cancer
2E-03
4E-04
6E-08
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2E-03
HI
12.9
2.1
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
15.1
Adult Resident
Cancer
8E-04
8E-04
6E-08
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2E-03
HI
1.4
1.2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.6
Lifetime
Resident
Cancer
3E-03
1E-03
1E-07
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA'
NA
4E-03
HI
3.7
1.4
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
5.1
On-site Worker
Cancer
3E-04
2E-04
5E-08
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
6E-04
HI
0.5
0.4
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.8
Site Visitor
Cancer
4E-05
2E-05
2E-09
2E-05
1E-05
2E-11
NA
NA
NA
NA
NA
NA
NA
NA
9E-05
HI
0.1
0.1
NA
0.1
0.03
NA
.0002
.0002
0.01
0.002
0.003
0.004.
0.03
0.004
0.4
NA = Not applicable
19
-------
Table 7
Summary of Potential Cancer Risks
and Non-Carcinogenic Hazard Quotients for
Individual Chemicals
Chemicals
of
Concern
Inadvertant
Ingestion
Cancer
Risk
Hazard
Quotient
Dermal Contact
Cancer
Risk
Hazard
Quotient
Inhalation of
Dust
Cancer
Risk
Hazard
Quotient
On-Site Worker Scenario
Arsenic
Dieldrin
4,4' -DDT
Toxaphene
IE- 06
1E-06
2E-05
3E-04
0.01
0.004
0.4
NA
3E-07
1E-06
2E-05
2E-04
0.001
0.003
0.3
NA
1E-09
1E-10
2E-09
3E-08
NA
NA.
NA
NA
Child Resident Scenario
Arsenic
Chromium VI
Iron
Lead
Vanadium
Aluminum
Beryllium
Benzo (a) -
pyrene
Dieldrin
4,4' -DDT
4,4' -DDE
4,4' -ODD
Endrin
Toxaphene
9E-06
NA
NA
NA
NA
NA
2E-06
3E-06
8E-06
1E-04
4E-06
3E-06
NA
2E-03
0.2
0.1
1.2
NA
0.1
0.1
0.0001
NA
0.1
10.0
0.3
0.3
0.5
NA
4E-07
NA
NA
NA
NA
NA
1E-07
5E-07
1E-06
3E-05
7E-07
6E-07
NA
3E-04
0.01
0.003
0.05
NA
0.00
0.01
0.002
NA
0.02
1.8
0.1
0.1
0.1
NA
1E-09
2E-08
NA
NA
NA
NA
8E-11
2E-11
1E-10
3E-09
NA
NA
NA
3E-08
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Adult Resident Scenario
Arsenic
Iron
Beryllium
Benzo (a) -
pyrene
Dieldrin
4,4' -DDT
4,4' -DDE
4,4' -ODD
Endrin
Toxaphene
4E-06
NA
1E-06
1E-06
3E-06
6E-05
2E-06
1E-06
NA
8E-04
0.02
0.1
0.0001
NA
0.01
1.1
0.03
0.04
0.1
NA
9E-07
NA
3E-07
1E-06
3E-06
6E-05
2E-06
1E-06
NA
8E-04
0.01
0.03
0.001
NA
0.01
1.0
0.03
0.03
0.1
NA
1E-09
NA
9E-11
2E-11
1E-10
3E-09
NA
NA
NA
3E-08
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA = Not applicable
20
-------
water drainage from the Site, other nearby facilities, and the highway.
The area has no wetlands identified by EPA's Advance Identification
wetlands project considered of high ecological value.
Although onsite, terrestrial vegetation, soil invertebrates, and animals
may have experienced adverse effects due to their exposures to chemicals of
potential concern (COPCs) in surface soil and sediment, these areas are
considered of limited habitat value because of their small size and lack of
ample surrounding habitat. Plants, soil invertebrates, herbivorous small
animals, and insectivorous birds exposed to COPCs in the depression
southwest of the Site may be adversely effected. However, this area cannot
offer an ample food supply to support animal populations, nor does it serve
as an important corridor for animals roaming between habitats. Aquatic
biota exposed to COPCs in the surge pond south of the Site may be adversely
effected, but wading piscivorous birds and waterfowl should not be affected
by exposure to COPCs.. The surge pond does not offer a unique or valuable
aquatic habitat, since more desirable habitats exist in the vicinity of the
Site.
6.6 CLEANUP GOALS
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 THAN site currently contain concentrations of Site-related
contaminants at levels which would pose an unacceptable risk (cumulative
risk in excess of IxlO"4 for cancer risks and/or hazard indices in excess
of 1 for non-cancer risks) to human health for current on-site workers
exposed to the soil. 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.
The cleanup levels.for soil are contained in Table 8. The soil cleanup
levels have been generated to ensure treatment of contaminated soil which
exceeds the health-based cleanup levels established at the IxlO"5 risk
level for carcinogenic contaminants and a hazard quotient level of 1 for
non-carcinogenic contaminants. A IxlO"5 risk level was chosen because it
falls within EPA's risk range of IxlO"4 and IxlO"6 and it results in a
significantly more cost effective remedy than the IxlO"6 risk level. This
cleanup level provides an acceptable exposure level that is protective of
human health and the environment in an industrial setting. Cleanup levels
for contaminated surface soil are based on an on-site worker exposure
scenario and assume an industrial land use. Cleanup levels for
contaminated subsurface soil are based on protection of groundwater.
21
-------
TABLE 8
Summary of Remedial Action Objectives
Compound
Manganese
4,4' -DDT
Ethylene dibromide
Methyl parathion
Toxaphene
Medium
Surface Soil
(mg/kg)
NA
94
NA
NA
29
Subsurface
Soil (mg/kg)
337
NA
0.006
17
NA
NA = Not applicable
The soil cleanup levels will be applied at the Site to ensure that current
on-site workers will not be exposed to unacceptable concentrations of
site-related chemicals and that groundwater will be protected. At the
IxlO"5 risk level and hazard quotient level of 1, cleanup levels are
necessary for 4,4'-DDT and toxaphene for surface soil. Metals were not
found in the surface soil at concentrations which exceeded health-based
levels. For subsurface soil, cleanup levels are necessary for manganese,
ethylene dibromide, and methyl parathion.
Transport modeling was used to evaluate the contribution of contaminated
subsurface soil to groundwater contamination. The PESTAN computer
transport model was used for organics to determine the levels of
contamination which can exist in the subsurface soil and not create a
condition in the groundwater whereby groundwater protection standards are
exceeded.
PESTAN was. developed by the EPA Robert S. Kerr Environmental Research
Laboratory in Ada, Oklahoma for estimating the vertical migration of
pesticides through soil to groundwater. The model presents an analytical
solution to a solute transport equation, considering sorption, dispersion,
and degradation. The model output consists of chemical concentrations at
varying depths in the unsaturated soil profile for specified times. The
model presents one-dimensional concentration profiles, assuming steady
state flow conditions in a single layer soil with constant sorption and
mass sink parameters. PESTAN is most applicable in the portions of vadose
zone located between the bottom of the root zone and the water table.
The PESTAN model was found to be most appropriate for the evaluation of
organics in the subsurface soils at the Site since it considers many
fate/transport properties, such as dispersion, sorption, and degradation.
The model also allows for evaluation of a contaminant "front" as it passes
through previously uncontaminated soil.
The PESTAN modeling results indicate that the low infiltration rate and
relatively low solubilities of the compounds found in operable unit 2 allow
contaminants to exist in the subsurface soils at high concentrations and
not cause the groundwater to exceed the groundwater protection standards.
Because of the low solubility, more contaminant mass in the subsurface soiY"
22
-------
does not result in higher concentrations in the resulting leachate, but
rather results in an increased amount of time for the slug to pass through
a particular depth in the soil profile.
The PESTAN modeling, coupled with the results of the subsurface soil
investigation performed during the RI, indicate that the subsurface soils
on the Site would contribute to groundwater contamination at concentrations
exceeding the groundwater protection standards for ethylene dibromide and
methyl parathion.
The Summers model was used to evaluate the fate of inorganic contaminant
transport in the subsurface soil at the Site. Summers was used due to the
lack of site specific distribution coefficients (Kd) for metals. The
Summers modeling, coupled with the results of the subsurface soil
investigation, indicate that the subsurface soils would contribute to
groundwater contamination at concentrations exceeding the groundwater-
protection standards for cadmium, lead, and manganese.
The Summers model was used to determine subsurface soil cleanup levels
based on their detection in both subsurface soils and earlier groundwater
samples. In the latest sampling efforts, low flow techniques have been
used in order to reduce turbidity effects on the samples and consequently
obtain a representative groundwater sample. The subsequent analysis has
detected only manganese. This manganese contamination is localized in the
area to the west of the main building above levels which could pose a
threat to groundwater. The result of this latest groundwater sampling
indicates that a subsurface soil cleanup level is only necessary for
manganese. Future groundwater monitoring for manganese, cadmium, and lead
will verify this conclusion.
7.0 DESCRIPTION OF ALTERNATIVES
Two alternatives for the remediation of contaminated soil at OU#2 of the
THAN site were evaluated in depth in the Feasibility Study Report and
listed in the Proposed Plan for the Site, along with the No Action
alternative. These alternatives are complete and address the remediation
of all the media. Table 9 summarizes the alternatives and their costs.
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 were analyzed. Two technologies 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 ALTERNATIVE NO. 1 - NO ACTION
The no action alternative is carried through the screening process as
required by the National Oil and Hazardous Substances Pollution Contingency
Plan (NCP). This alternative is used as a baseline for comparison with
other alternatives that are developed. Under this alternative, EPA would
take no further action to minimize the impact soil contamination has on the
area. Soil contamination would remain and possibly migrate due to surface
runoff. The cost for this alternative is for continued monitoring of the
soil and groundwater quality at the Site. The cost for this alternative is
$157,000.
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Table 9
Operable Unit #2 Alternatives
Alternative
Number
Remedial Action
Present Worth
No Action
$157,000
2 A/B
Excavation & Onsite Treatment with
Thermal Desorption; Onsite
Disposal
$5,400,000
or
$2,500,000
3 A/B
Excavation & Offsite Disposal
$4,500,000
or
$1,000,000
(Non-hazardous)
$8,000,000
or
$1,600,000
(Hazardous)
7.2 ALTERNATIVE NO. 2 A/B - EXCAVATION AND THERMAL DESORPTION
WITH QNSITE DISPOSAL
This alternative involves excavating contaminated surface and subsurface
soil necessary to meet the RA objectives. Onsite treatment would be low
tempera'ture thermal desorption. The treated soil would be backfilled
onsite. The final treatment system would depend on the outcome of
treatability testing and would be determined during the remedial design
phase. Alternative 2 has been divided into two sub-alternatives which vary
in scope. Alternative 2A would consist of excavating all contaminated soil
necessary to meet the remedial action objectives, which involves an
estimated 19,174 cubic yards. Under Alternative 2B, organic-contaminated
soil would be excavated, but metals contaminated soils would remain in
place. This sub-alternative is included because the groundwater
contamination by metals appears to be isolated (located immediately west of
the main building) and does not appear to be migrating. The estimated
volume of soil for Alternative 2B is 3,060 cubic yards. The cost of this
alternative is estimated to be $5,400,000 if all contaminated soil is
excavated and treated and $2,500,000 if only soil contaminated with
organics is excavated and treated.
7.3 ALTERNATIVE NO. 3 A/B - EXCAVATION AND OFFSITE DISPOSAL
This alternative involves excavating contaminated surface and subsurface
soil 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 at the
facility before disposal. Alternative 3 has been divided into two
alternatives which vary in scope. Alternative 3A would involve excavating
all contaminated soil. Alternative 3B would consist of excavating only
soil contaminated with organics. Metals contaminated soils would remain
place. This sub-alternative is included because the groundwater
24
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contamination by metals appears to be isolated (located immediately west of
the main building) and does not appear to be migrating. Assuming that the
soil is a RCRA hazardous waste, the estimated cost is $8,000,000 for all
contaminated soil (3A) and $1,600,000 for soil only contaminated with
organics (3B). If the soil is not characterized as a RCRA hazardous waste,
it would be transported to a Subtitle D landfill. The estimated cost of
this alternative would then be $4,500,000 for all contaminated soil and
$1,000,000 for only soil contaminated with organics.
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
This section of the ROD provides the basis for determining which
alternative provides the best balance with respect to the statutory
balancing criteria in Section 121 of CERCLA and in Section 300.430 of the
NCP. The major objective of the FS was to develop, screen, and evaluate
alternatives for the remediation of Operable Unit Two at the THAN 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:
(1) 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-term effectiveness; 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
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comment is received on the proposed plan and incorporated in the
ROD.
The selected alternative must meet the requirement for overall protection
of human health and the environment and comply with all ARARs or be granti
a waiver for compliance with ARARs. Any alternative that does not satisff
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 the THAN 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
Alternative 1 would not contain or remediate the soil contamination.
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. Alternative 2
would remediate contaminated soil with onsite treatment to reduced risk
levels. Alternative 3 would remove the contaminated soil from the site to
reduce risks. Sub-alternative B for both alternatives would be less
effective, since metal-contaminated soil would remain in place, but these
sub-alternatives are still protective of human health and the environment
For Alternatives 2 and 3, cleanup would reduce risks to a 10~5 additional
risk for direct contact with soils by on-site workers, which is within
EPA's acceptable risk range.
8.2 COMPLIANCE WITH ARARS
The potential ARARs for this Site are listed in Table 10, 11, and 12.
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 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 not 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.
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TABLE 10
POTENTIAL CONTAMINANT-SPECIFIC ARARS
Standard, Requirement, Criteria, or
Limitation
Citation
Description
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
Clean Air Act
National Primary and Secondary Ambient Air
Quality Standards
National Emissions Standards for Hazardous
Air Pollutants (NESHAPs)
Solid Waste Disposal Act (SWDA)
Land .Disposal Restrictions
40 USC Section 300
40 CFR Part 141
40 CFR Part 143
40 CFR Part 141
33 USC Section 1251-1376
40 CFR Part 131 Quality
Criteria for Water,
1976, 1980, 1986
42 USC Section 6905,
6912, 6924, 6925
40 CFR Part 264
42 USC Section 7401-7642
40 CFR Part 50
40 CFR Part 61
42 USC Section 6901-6987
40 CFR Part 268.10-12;
40 CFR Part 268 tSubpart
D)
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 for groundwater protection standards, general
monitoring requirements, and technical requirements.
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.
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
Chapter 391-3-6
Chapter 391-3-5
Chapter 391-3-1
Section 02
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.
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TABLE 11
POTENTIAL LOCATION-SPECIFIC ARARS
Standard, Requirement, Criteria, or
Limitation
Citation
Description
Federal
RCRA, as amended
RCRA Location Standards
Fish and Wildlife Conservation Act
Floodplain Management Executive
Order
Endangered Species Act
42 USC Section 6901
40CFRPart264.18(b)
16 USC Part 2901 et seq.
Executive Order 11988;
40 CFR Part 6.302
16 USC Section 1531
Establishes design, construction, operation and
maintenance standards for treatment/storage/disposal
(TCD) facilities constructed in a 100-year floodplain.
Requires states to identify significant habitats and develop
conservation plans for these areas.
Actions that are to occur in floodplain should avoid adverse
effects, minimize potential harm, restore and preserve
natural and beneficial value.
Requires action to conserve endangered species or
threatened species, including consultation with the
Department of Interior.
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TABLE 12
POTENTIAL ACTION-SPECIFIC ARARS
Standard, Requirement, Criteria,
or Limitation
Citation
Description
Federal
Solid Waste Disposal Act (SWDA)
Criteria for Classification of Solid
Waste Disposal Facilities and Practices
Hazardous Waste Management
Systems General
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
Hazardous Materials Transportation
Regulations
42 USC Section
6901-6987
40 CFR Part 257
40 CFR Part 260
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
49 CFR 107, 171-177
Establishes criteria for use in
determining which solid waste disposal
facilities and practices pose a
reasonable probability of adverse effects
on health, and thereby constitute
prohibited open dumps.
Establishes procedure and criteria for
modification or revocation of any
provision in 40 CFR Parts 260-265.
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 part
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 transportation of hazardous
materials.
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Standard, Requirement, Criteria,
or Limitation
Occupational Safety and Health
Act
Clean Air Act
National Ambient Air Quality
Standards
Air Use Approval
Particulate Discharge Limitations and
Performance Testing
Hazardous Materials
Transportation Act
Hazardous Materials Transportation
Regulations
Citation
20 USC Section 651-
678
42 USC Section
7401-7642
40 CFR Part 50
40 CFR 60
(Subpart A)
40 CFR 60
(Subpart B)
49 USC Section
1801-1813
49 CFR Parts 107,
171-177
Description
Regulates worker health and safety.
Treatment technology standard for
emissions to air
incinerators
surface impoundments
waste piles
landfills
fugitive emissions
Requires notification and performance
testing by owner or operator.
Defines limitations for parti culate
emissions, test methods, and monitoring
requirements for incinerators.
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
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.
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TABLE 13
TO-BE-CONSIDERED (TBCs) DOCUMENTS1
Document
Georgia Hazardous Site Response Act
(HSRA)
Citation
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.
Primary Balancing Criteria
8.3 LONG-TERM EFFECTIVENESS AND PERMANENCE
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 metals-contaminated
soil would remain on site, but these sub-alternatives are still protective
of human health and the environment.
8.4 REDUCTION OF TOXICITY, MOBILITY OR VOLUME THROUGH TREATMENT
Alternative 2 would reduce mobility and toxicity through treatment.
Alternative 3 would reduce mobility of contamination by removing
contaminated soil off-site and placing the soil in a landfill which would
contain the contamination. 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, since metals-contaminated soil would remain on site.
8.5 SHORT-TERM EFFECTIVENESS
Alternative 2 would require approximately 2 years and Alternative 3 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 for Alternatives 2 or 3.
8.6 IMPLEMENTABILITY
Technological expertise, services, equipment and materials are adequately
available for the implementation of Alternatives 2 and 3. Alternative 2
would require a longer period to implement due to the on-site treatment of
the contaminated soil.
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8.7 COST
The total present worth cost of Alternative 2 is approximately $5,400,000
if all contaminated soil is excavated and treated and $2,500,000 if only
organic-contaminated soil is excavated and treated. For disposal at a noij
hazardous waste landfill, the total present worth cost for Alternative 3 r
approximately $4,500,000 if all contaminated soil is removed and
approximately $1,000,000 if only organic-contaminated soil is removed. For
disposal at a hazardous waste facility, the total present worth cost for
Alternative 3 is approximately $8,000,000 if all contaminated soil is
removed and approximately $1,400,000 if only organic-contaminated soil is
removed.
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 the T H
Agriculture & Nutrition site. In accordance with 40 CFR 300.430, as the
support agency, GaEPD has provided input during this process. The State of
Georgia, as represented by GaEPD, has concurred with the selected remedy.
8.9 COMMUNITY ACCEPTANCE
During the public comment period, comments were received on the proposed
plan from three commenters. See Appendix A - Responsiveness Summary for
EPA's responses to the comments.
9.0 SUMMARY OF SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the NCP, the
detailed analysis of alternatives and public and state comments, EPA has
selected a remedy for Operable Unit 2 of the Site. The selected remedy is
Alternative 2B, which provides for the following:
1. Excavation of all soil contaminated with organics necessary to
meet performance standards for organics (See Table 14) .
2 . The staging and preconditioning of soil for low temperature
thermal desorption treatment.
3 . Treatment of excavated soil by low temperature thermal
desorption.
4. Placement of treated, decontaminated soil back to the site.
5. Periodic sampling of treated soil during the treatment process to
verify the effectiveness of the remedy.
6. Air monitoring to ensure the safety of nearby residents and
workers.
7 . Monitoring of groundwater on an annual basis for five
years to ensure that metals contamination of groundwater is not]
migrating offsite in concentrations which exceed groundwater
32
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protection standards. Monitoring may be suspended with EPA
approval after two years if groundwater protection standards are
met.
8. Deed restrictions to prevent residential use of the property.
At the completion of this remedy, the risk associated with this Site has
been calculated at IxlO"5 which is determined to be protective of human
health and the environment. The total present worth cost of the selected
remedy, Alternative 2B, is estimated at $2,500,000.
9.1 SOIL REMEDY
The selected remedy for contaminated soils is low temperature thermal
desorption. This remedy includes the utilization of a mobile thermal
treatment unit to remove contaminants from soil at OU2 of the THAN site.
The low temperature thermal desorption unit consist of a heated chamber
with temperatures ranging from 300 - 1,200 degrees Fahrenheit, depending on
the specific type of unit. Approximately 3,000 cubic yards of organic-
contaminated soil would be excavated, broken up, preconditioned (if
necessary), and fed into the chamber of the desorption unit. The thermal
unit will drive off organic contaminants from the soil. The contaminants
in the vapor would be treated onsite by activated carbon, baghouses or an
equivalent system. The soil will be treated to meet the performance
standards outlined in Table 14. The treated soil will be placed back at
the site.
In order to facilitate this remedy, OU2 of the THAN site is designated as a
Corrective Action Management Unit (CAMU)' and an Area of Containment (AOC)
for purposes of this ROD. All waste managed within the CAMU/AOC must
comply with the requirements set out in this ROD for soil remediation. OU2
and the designated CAMU/AOC consists of the Jones property and is bordered
by the THAN property on the west, Schley Boulevard on the south, residences
and a U.S. Department of Agriculture laboratory on the east, and the Albany
Motel Limited property on the north. The CAMU/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 CAMU/AOC.
Major components of the soil remedy include:
* The excavation of organic-contaminated surface and subsurface
soils (approximately 3,000 cubic yards) which exceed action
levels.
* The staging and preconditioning (if necessary) of soil for entry
into the thermal desorption unit.
* The feeding of contaminated soil into the heated chamber for
treatment.
* The processing of contaminated soil through the thermal
desorption unit including the activated carbon, baghouse, or
equivalent system.
* The placement of treated soil back to the site.
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* The periodic sampling of soil during treatment to verify
effectiveness of the remedy.
* Air monitoring to ensure safety of nearby residents and workers.
* Demobilization and restoration of the site property after
completion of the remedy.
* Monitoring of groundwater for metals on an annual basis for five
years.
* Institutional controls to prevent residential use of the site.
9.2 PERFORMANCE STANDARDS FOR SOIL
For the low temperature thermal desorption remedy, the performance
standards for surface soil are based upon a IxlO"5 risk level for a cleanup
associated with current and future industrial land use. Because an
operating welding supply company exists on the eastern parcel and the
property is zoned for commercial use through the year 2010, an industrial
scenario was selected for operable unit two. A IxlO'5 risk level was
chosen because it falls within EPA's risk range of IxlO"4 and IxlO"6 and it
results in a significantly more cost effective remedy than the IxlO"6 risk
level. This risk level remains protective of human health and the
environment. For the subsurface soil the cleanup level was calculated
using the PESTAN and Summers groundwater models. Performance standards are
outlined in Table 14. Excavation of organic-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.
All excavated soil shall be treated by means of a mobile low temperature
thermal desorption unit to the performance standards outlined in Table 14.
All treatment shall comply with ARARs, OSHA, and state standards. Treated
soil will be used to backfill the site if it achieves the performance
standards, otherwise it will be treated again by the thermal desorption
unit until performance standards are achieved.
EPA has determined that excavation of metals-contaminated soil is not
necessary. Metals concentrations in surface soil are below the IxlO"5 risk
level or hazard quotient of 1. Metals in subsurface soil were examined to
determine if the migration of metals to groundwater. was possible. The
metals selected for examination were beryllium, cadmium, lead, and
manganese. This selection was based on the presence of these metals in
groundwater at levels above drinking water or other health based standards
in early sampling events. Computer modeling using the Summers model
concluded that concentrations of cadmium, lead, and manganese in the
subsurface soil were at levels which could result in migration of the
contaminants into the groundwater. Beryllium concentrations were below
levels which could result in migration into the groundwater.
Subsequent sampling of the groundwater at OU2 using low-flow techniques
found that manganese is the only metal of concern in the groundwater.
Manganese contamination in the groundwater at OU2 appears to be restricted
to the area west of the main building. This is also the area of the
highest subsurface soil contamination. Manganese contamination was not
found in the monitoring wells to the east of the building (which is
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downgradient of the contamination). The result of these sampling events
indicates that a subsurface soil cleanup level is only necessary for
manganese. The groundwater will be monitored for cadmium, lead, and
manganese on an annual basis for five years to ensure that metals
contamination of groundwater is not migrating offsite in concentrations
that exceed groundwater protection standards. If monitoring indicates that
metals contamination is migrating offsite, EPA would then consider
additional cleanup, such as excavating and treating metals-contaminated
soil. The public would be notified if additional activities were being
considered.
TABLE 14
Summary of Remedial Action Objectives
Compound
4,4' -DDT
Ethylene dibromide
Methyl parathion
Toxaphene
Medium
Surface Soil
(mg/kg)
94
NA
NA
29
Subsurface
Soil (mg/kg)
NA
0.006
17
NA
NA = Not applicable
9.3 SOIL TESTING
Soil testing shall be conducted on the site to determine the effectiveness
of meeting the soil performance standards outlined in Table 14.
Performance will be met when the confirmatory sampling effort shows all
surface soil samples have been remediated to a level at or below the
performance standards and subsurface soils meet the performance standards
on a site-wide basis. Confirmatory sampling will include testing of both
the decontaminated soil exiting the thermal desorption unit and any soil
left in place.
9.4 COST
For low temperature thermal desorption, the estimated present worth cost of
the remedy is approximately $2,500,000. These costs include planning and
design fees, as well as mobilization and implementation. The capital cost
is approximately $2,000,000; the operation and maintenance cost is
approximately $500,000.
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
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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
isolating and treating threats at Operable Unit 2 of the Site in the
contaminated soil. The selected remedy provides protection of human health
and the environment by eliminating, reducing, and controlling risk through
treatment and institutional controls. The surface and subsurface soils at
Operable Unit 2 of the Site will be treated through low temperature thermal
desorption. For surface soil the cleanup will meet a IxlO'5 risk-based
level . The subsurface soils will be cleaned up to levels that are
protective of groundwater for organic contamination. Although metals
contaminated soil will be left in place at a level that could impact
groundwater, groundwater monitoring will be implemented to ensure that
metals contamination of groundwater does not migrate offsite in
concentrations which exceed groundwater protection standards.
10 .2 ATTAINMENT OF THE APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
(ARARs)
Remedial actions performed under CERCLA must comply with all applicable or
relevant and appropriate requirements (ARARs) . All alternatives consideraA
for the THAN 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, 11, and 12.
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.
Other Guidance To Be Considered
Other Guidance To Be Considered (TBCs) include health based advisories and
guidance. TBCs have been utilized in estimating incremental cancer risk
numbers for remedial activities at the sites. The risk numbers are
evaluated relative to the normally accepted point of departure risk range
of IxlO'4 to
10.3 COST EFFECTIVENESS
The estimated cost of EPA's selected remedy is $2,500,000. 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. EPA evaluates the
incremental cost of each alternative as compared to the increased
effectiveness of the remedy. The selected remedy, Alternative 2B, does
cost more than the no action alternative; however, effectiveness achieved'
by Alternative 2B justifies the higher cost. The selected remedy also
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costs more than Alternative 3B. However, the reduction in mobility and
toxicity achieved by Alternative 2B justifies the additional cost. The
selected remedy is less costly that Alternatives 2A and 3A, which would
address subsurface soil contamination with metals. However, the
incremental increase in effectiveness under 2A or 3A would not justify the
substantial increase in cost. The remedy is considered cost effective.
10.4 UTILIZATION OF PERMANENT SOLUTIONS TO THE MAXIMUM EXTENT PRACTICABLE
The selected remedy utilizes permanent solutions to the maximum extent
practicable by using treatment to permanently reduce contaminant levels.
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The statutory preference for treatment will be met because the selected
remedy treats the contaminated soil which is the principal threat posed by
Operable Unit 2 at the Site.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
This selected remedy differs from the preferred remedy in the proposed plan
in removing cadmium, lead and manganese as contaminants of concern. As
discussed above, subsequent groundwater monitoring has found that cadmium
and lead are not migrating into the groundwater and that manganese is
isolated to the area on the west side of the main building. The period of
groundwater monitoring for metals also has been changed to five years to
ensure protection of groundwater resources. In addition, deed restrictions
to prevent residential use of the property were added to the remedy.
In order to facilitate this remedy, OU2 of the THAN Site is designated as a
Corrective Action Management Unit (CAMU) and an Area of Containment (AOC)
for purposes of this ROD. All waste managed with the CAMUXAOC must comply
with the requirements set out in the ROD for soil remediation. OU2 and the
designated CAMU/AOC consist of the Jones property and is bordered by the
THAN property on the west, Schley Boulevard on the south, residences and a
U.S. Department of Agriculture laboratory on the east, and the Albany Motel
Limited property on the north. The CAMU/AOC also includes suitable areas
in close proximity to the contamination necessary for implementation of the
selected remedy. Since soil contamination at OU2 will be cleaned to the
risk-based performance standards, no closure standards apply for this
CAMU/AOC.
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APPENDIX A
Responsiveness Summary
T H Agriculture & Nutrition Site
Operable Unit 2
Albany, Georgia
The U.S Environmental Protection Agency (EPA) held a public comment period
from January 31, 1996 through March 1, 1996 for interested parties to give
input on EPA's Proposed Plan for Remedial Action at Operable Unit 2 (OU2)
of the T H Agriculture & Nutrition (THAN) Superfund Site in Albany,
Dougherty County, Georgia. The public comment period was extended an
additional thirty days, until April 1, 1996, 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 final decision of the remedial action for OU2 of the T H Agriculture &
Nutrition Site.
This responsiveness summary for the T H Agriculture & Nutrition 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.
II. Background on Community Involvement and Concerns - This
section provides a brief history of community interest and concerns
regarding the THAN Site.
Ill. Summary of Manor 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 were presented to the public in a Proposed Plan
released in January 1996. The public comment period was January 31, 1996
through April 1, 1996. Public notices in the Albany News-Herald were
published on January 31, 1996 and February 3, 1996. A public notice was
published in the Southwest Georgian on February 1, 1996 and in the Albany
Journal on February 9, 1996. The public notice indicated the EPA wold hold
a public meeting if requested by the public. Notice of the extension to
the public comment period was published in the Albany News-Herald on
February 19, 1996 and March 4, 1996. A public meeting was not requested by
the public.
EPA has organized the work at this Site into two phases or operable units
(OUs) . OUl involves the eastern parcel currently owned by T H Agriculture
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& Nutrition Company, Incorporated. A removal action on OUl was performed
in 1992 to excavate and treat contaminated soils. Current remedial actions
on OUl are addressing groundwater contamination underneath the entire Site
and soil on the western parcel. Operable unit two addresses the source of
contamination on the eastern parcel currently owned by Mr. Larry Jones whi
operates the Jones Welding Supply Company.
For the contaminated soils on OU2, the selected remedy is Alternative 2B,
Excavation and Onsite Treatment with Thermal Desorption and Onsite
Disposal. The major components of the selected remedy include:
* Excavation of organic-contaminated surface and subsurface
soils necessary to meet action levels for organics,
* Treatment of contaminated soils by low temperature
thermal desorption,
* Backfilling of treated soils on the site, and
* Monitoring of groundwater for metals on an annual basis
for five years. (Monitoring may be suspended with EPA approval
after two years if groundwater protection standards are met.)
* Deed restrictions to prevent residential use of the
property.
The estimated cost of this alternative is $2,500,000.
This selected remedy differs from the preferred remedy in the period of
groundwater monitoring which has been changed from two years to five years,
to ensure protection of groundwater resources. In addition, deed
restrictions to prevent residential use of the property were added to the
remedy.
In order to facilitate this remedy, OU2 of the THAN Site is designated as a
Corrective Action Management Unit (CAMU) and an Area of Containment (AOC)
for purposes of this ROD. All waste managed within the CAMU/AOC must
comply with the requirements set out in the ROD for soil remediation. OU2
.and the designated CAMU/ AOC consist of the Jones property and is bordered
by the THAN property on the west, Schley Boulevard on the south, residences
and a U.S Department of Agriculture laboratory on the east, and the Albany
Motel Limited property on the north. The CAMU/AOC also includes suitable
areas in close proximity to the contamination necessary for implementation
of the selected remedy. Since soil contamination at OU2 will be cleaned to
the risk-based performance standards, no closure standards apply for this
CAMU/AOC.
II. Background on Community Involvement and Concerns
EPA has taken the following actions to ensure that interested parties have
been kept informed and given an opportunity to provide input on activities
at the THAN OU2 Site.
An availability session at a local library and community interviews with
local officials were held at the start of field work for the RI for
operable unit one on December 12, 1990. The main branch of the Dougherty
Public Library at 300 Pine Street was chosen as the local information
repository for the Site. On March 12, 1992, THAN held a public meeting to
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discuss the second removal action at the Site. In addition, a fact sheet
concerning the RI for operable unit one was sent to the mailing list in May
1992.
The public comment period on the proposed plan for the operable unit one
ROD was September 14, 1992 through November 14, 1992. A public meeting was
held on Thursday, September 24, 1992 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 repository maintained at the Dougherty Public Library and at
the EPA Region IV Library at 345 Courtland Street in Atlanta, Georgia. The
notice of availability of these two documents was published in the Albany
News-Herald on September 10, 1992. Responses to the significant comments
received during the public comment period and at the public meeting were
included in the Responsiveness Summary/ which was part of the ROD for
operable unit one.
The public comment period on the proposed plan for this ROD was January 31,
1996 through April 1, 1996. EPA published notice that it would hold a
public meeting upon request of the community.. However, a public meeting
was not requested by the public. The administrative record was available
to the public at both the information repository maintained at the
Dougherty Public Library and at the EPA Region IV Library at 345 Courtland
Street in Atlanta, Georgia. The notice of availability of these documents
was published in the Albany News-Herald on January 31, 1996 and February 3,
1996, in the Southwest Georgian on February 1, 1996, and in the Albany
Journal on February 9, 1996. Notice of the extension of the comment period
was published in the Albany News-Herald on February 29, 1996 and March 4,
1996.
Ill. Summary of Manor Questions and Comments Received During the
Public Comment Period and EPA's Responses
Comment 1: The property owner requested additional information regarding
risk to on-site workers.
Response 1: The risk to on-site workers is a long-term risk caused by
direct exposure to the soils. Because the area of highest contamination is
not an area with day-to-day operations, the exposure of on-site workers is
limited and would only be of concern after many years. The site will be
cleaned before the on-site workers have significant exposure.
Comment 2: The property owner requested additional information regarding
the impact of the clean-up to property and business operations.
Response 2: The area of highest contamination is located on the west side
of the existing building. EPA will attempt to conduct the clean-up with
minimal or no disruptions to the building or the operations.
Comment 3 : One commenter suggested that bioremediation should have been
carried through to the final stage of remedial alternative screening.
Response 3: The bioremediation alternative was screened out because it was
not a viable alternative. This commenter presented data that demonstrated
toxaphene was degraded from 40 mg/kg to less that 2 mg/kg. However, in the
same data when starting concentrations of toxaphene were higher (577 mg/kg
and 1050 mg/kg), the final concentrations were 270 mg/kg and 244 mg/kg
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respectively, which does not meet the cleanup standards for this site.
Comment 4: One Potentially Responsible Party (PRP) commented that they
agree with EPA's conclusion regarding the need to remediate only organic-
contaminated soil.
Response 4: No response needed.
Comment 5: One PRP commented that risk assessment scenarios that are more
representative of actual current conditions need to be evaluated. A more
realistic current exposure would be for an occasional trespasser or grounds
maintenance personnel or possibly a guard at the site. Scenarios for
future conditions need to consider potential institutional controls such as
deed restrictions that may limit future use of the property to industrial
applications only.
Response 5: The current use of the site is an operating welding supply
company. Although the facility does not use the west side of the building
(which is most highly contaminated) on a day-to-day basis at this time,
this area could be used at any time in the future resulting in unacceptable
risk to on-site workers. Deed restrictions have been included in the
remedy to limit future use of the property to industrial applications.
Comment 6: One PRP commented that cleanup standards for soils should be
reevaluated after the risk assessment has been updated. Cleanup standards
for surface soil should consider exposure to on-site workers and protection
of surface water runoff. Cleanup standards for subsurface soil should
consider potential exposure to construction workers.
Response 6: EPA does not agree that the risk assessment should be updated
The risk assessment should be updated only if new issues of protectivenes
arise. Cleanup standards for surface soil have been set to protect on-sit:e~
workers. Cleanup standards for subsurface soil have been set to protect
groundwater from contamination. These subsurface standards will be
protective of short-term exposure by construction workers.
Comment 7: One PRP suggested that additional remedial alternatives should
be considered in light of more realistic risk assessment alternatives and
revised cleanup standards. Remediation of surface soil only, institutional
controls, in-situ soil stabilization and solidification, and containment
technologies such as capping should be considered.
Response 7: EPA does not agree that the cleanup standards should be
revised. EPA considered stabilization/solidification and containment
technologies. However, these alternatives are not as effective at reducing
toxicity and volume of waste and are considered less protective. EPA has
included institutional controls (deed restrictions) in the remedy.
Comment 8: One PRP states that while the preferred alternative presented
in the Proposed Plan is protective of human health and the environment,
there are several less costly alternatives (institutional controls, deed
restrictions, in-situ treatment, and containment by capping) that would
achieve an acceptable reduction of risk, thus meeting the objectives of the
National Oil and Hazardous Pollution Contingency Plan (NCP). In light of
the comments above, these alternatives should be evaluated and the proposed
plan revised accordingly.
Response 8: See response 7.
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Comment 9: One PRP commented that the Feasibility Study for OU2 is
questionable in that it appears to have relied upon the results of computer
modeling to conclude that there are inorganic compounds at the Jones
property that should be remedied. The modeling is poorly documented and
appears to depend on general rules of thumb or estimates for many of the
input parameters.
Response 9: The Feasibility Study utilized computer modeling to determine
that subsurface metal contamination could continue to contaminate
groundwater resources. Metals concentrations of beryllium, cadmium, lead,
and manganese in the soil were significantly above background levels for
the site and these same metals were found in earlier groundwater samples
from the site.
In the latest sampling efforts, low flow techniques have been used in order
to reduce turbidity effects on the samples and consequently obtain a
representative groundwater sample. The subsequent analyses have detected
only manganese. This contamination is localized in the area to the west of
the main building. Therefore, cadmium and lead were removed from the list
of contaminants of concern and manganese will continue to be sampled and
monitored.
Comment 10: One PRP stated that analytical data does not support the
Feasibility Study (FS) statement that inorganic contamination extends from
1 to 22.5 feet; the comparison of maximum detected concentrations of the
metals to a cleanup standard is inappropriate; that maximum detected lead
concentrations did not exceed the industrial worker exposure limit of 1000
parts per million; and that the manganese occurrence is not as extensive as
implied by the FS.
Response 10: The Remedial Investigation for this site found levels of
inorganic contamination from 1 to 22.5 feet below surface which exceeded
the background levels for this site. Maximum concentrations were compared
to cleanup standards as a conservative approach for protection of
groundwater. The maximum detected lead concentrations did not exceed the
industrial worker limit, but did result in groundwater contamination when
used in the groundwater model. Lead has subsequently been removed as a
contaminant of concern for subsurface soil. Manganese occurrence in excess
of the maximum subsurface soil background concentration of 269 mg/kg is
frequent; manganese concentrations in groundwater in excess of the national
maximum of 3000 mg/kg occur in multiple wells.
Comment 11: One PRP stated that the maximum detected lead and manganese
are in subsurface samples which should be compared with leachability values
calculated using site-specific Kd values.
Response 11: EPA is aware of the value of site specific soil/water
distribution coefficients (Kd). Because site specific data was not
available, EPA decided to develop soil clean-up levels for inorganics using
literature derived values. In order to account for natural variation in
the Kd, the Summer's model and conservative input values were chosen for
the purpose. In addition, the protective measure of monitoring of
groundwater for inorganic contamination has been provided in the ROD. This
monitoring will provide verification of leachability of inorganics and
protection of human health and the environment at the site.
Comment 12: One PRP stated that if a localized source of metals exists,
then a localized action may be recommended.
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Response 12 : EPA agrees with this comment, but has no knowledge of any
localized source of metals. The subsurface manganese contamination appears
to be concentrated on the west side of the main building, but the source of
this contamination is unknown.
Comment 13: One PRP stated that Figure 2-3 of the FS shows the extent of
metals contamination including samples JP-25, JP-33 and JP-47, but the
analytical data does not support the figure.
Response 13: Samples JP-25, JP-33, and JP-47 had concentrations of one or
more metal which significantly exceeded the background concentrations for
the site.
Comment 14: One PRP stated that the site-specific Risk Assessment and
Remedial Investigation (RI) data do not support remediation of soils for
inorganic contamination for the protection of human health and the
environment.
Response 14: The data from the RI/FS for OU1, the RI for OU2, and
subsequent groundwater sampling events indicate that manganese is present
in elevated levels which are causing contamination of groundwater in a
local area to the west of the main building. The selected remedy includes
continued groundwater sampling and monitoring to determine if remediation
of subsurface soils is necessary.
Comment 15: One PRP stated surface and subsurface soils- have levels of
pesticides, toxaphene, and DDT and its degradation products, DDD and DDE,
that require remediation. The other co-occurring pesticides (dieldrin,
endosulphan, dinoseb, and so forth) will be removed if toxaphene and DDT
are addressed in remediation, but because of their low detected
concentrations, they do not require remediation. None of the other
volatile organic compounds (VOCs), semivolatile organic compounds (VOCs)
metals require remediation.
Response 15; EPA agrees with the statement regarding toxaphene and DDT for
the surface soil remediation. However, groundwater modeling indicates that
methyl parathion and ethylene dibromide are contaminants of concern for
subsurface soil due to the likelihood of leaching into the groundwater.
v
Comment 16: One PRP stated that the executive summary of the Remedial
Investigation (RI) report wrongly presents xylene as a potential problem at
the site.
Response 16: The RI states that "soils in the southwestern portion of the
site are contaminated with toxaphene and xylene." The OUl RI and OU2 RI
found xylene contamination in several samples which was consistent with
previous operations at the site.
Comment 17: One PRP stated that none of the metals detected appeared to be
at elevated concentrations (above naturally occurring levels).
Response 17: Many of the samples from both the OUl and OU2 RI had levels
of metals which significantly exceeded the background level for the site.
In the latest sampling efforts, low flow techniques have been used in order
to reduce turbidity effects on the samples and consequently obtain a
representative groundwater sample. The subsequent analyses have detected
only manganese. This contamination is localized in the area to the west of
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the main building. Therefore, cadmium and lead were removed from the list
of contaminants of concern and manganese will continue to be sampled and
monitored.
Comment 18: One PRP stated that all of the reported semivolatile organic
compounds were estimated concentrations and appear to be within the
detection limit ranges. None of them appear to be in significant
concentrations to be of exposure concern.
Response 18: EPA agrees that the semivolatiles do not appear to be
contaminants of concern.
Comment 19: One PRP stated that Table 2-1 in the Risk Assessment (RA)
reported mean values higher than the maximum values, that cancer risks in
the RA were estimated using a dose averaging time of 75 years, instead of
the standard of 70, and that a conversion factor was omitted from the
equation for the soil intake estimates.
Response 19: EPA found no occurrences in Table 2-1 of the RA document
where the reported mean value was higher than the maximum. The cancer
risks were estimated using the standard of 70 years. The conversion factor
was included in the equation for the soil intake estimates.
Comment 20: One PRP stated that the RA addressed only surface soil
contamination.
Response 20: Since no direct routes of exposure are anticipated for
current and future use of the property, direct subsurface exposure was not
addressed in the RA. Subsurface contamination was addressed in the
Feasibility Study for protection of groundwater.
Comment 21: One PRP stated that a fate and transport discussion is lacking
in the RA.
Response 21: Although a fate and transport discussion is not provided, the
report satisfies the requirements established by EPA. In addition, a fate
and transport discussion is provided in the RI/FS for Operable Unit 1.
Comment 22: One PRP stated that analytical data used in the RA should be
included in the report or referenced in the report.
Response 22: The data were obtained from the EPA RI report cited in
Section 2-2.
Comment 23: One PRP stated that the exposure point concentration estimates
in the RA assumed that all data are lognormally distributed for the
Reasonable Maximum Exposure (RME) calculation. However, the DDT
concentrations used were the maximum detected concentrations which could
mean that the data distribution assumptions may not be accurate.
Response 23: The RME calculation was performed according to EPA guidance.
When the calculated upper confidence limit is greater that the maximum
detected concentration, the RME defaults to the maximum detection as was
done for DDT.
Comment 24: One PRP stated that the Feasibility Study report presented
Remedial Action Objectives (RAOs) based on the protection of groundwater
for methyl parathion and EDB which were not even reported in the RA.
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Response 24: Subsurface soil was not an issue for the risk assessment as
explained in response 20. However, subsurface soil contamination is an
issue for the protection of groundwater and RAOs were appropriately
determined using leachate model results.
Comment 25: One PRP stated that for oral and inhalation exposure pathway^
in the RA, the EPA cancer slope factor (CSF) and reference dose (RfD)
values were used. For dermal intake estimations, modified CSF and RfD
values were used, which is technically incorrect.
Response 25: Toxicity factors were adjusted from administered to adsorbed
toxicity factors as noted in Section 4.1 of the RA. The method is
consistent with Appendix A to the Risk Assessment Guidance for Superfund
(RAGS) . Further, the absorption percentages that were used are consistent
with the EPA policy cited in Section 4.1.
Comment 26: One PRP stated that the exposure pathway evaluations, in the RA
are not realistic. The exposure pathways included on-site workers and
youth trespassers for current land use and. on-site residents for future
land use.
Response 26: The exposure setting of the Jones property is described in
Section 3. Currently, the site is used for commercial purposes and
residential areas are located in close proximity; thus, on-site workers and
site visitors are potential receptors. Residential use of the property is
an unlikely, but possible, future use scenario. The western parcel of the
site already has stopped commercial operations, so residential use is not
impossible.
Comment 27: One PRP stated that exposure factors used in the RA are, for
the most part, the default exposure factors from EPA. The assumptions us<
are not realistic for the current land use at the site.
Response 27: The exposure factors that were used were a combination of
standard default exposure factors and professional judgement. This
approach is typically used when site-specific data is lacking.
Comment 2 8: One PRP stated that a site land use map is needed to properly
evaluate the future land use.
Response 28: EPA used the Albany-Dougherty Planning Commission's
"Comprehensive Development Plan", June 1989, for projected land use in the
area. Commercial zoning of the property through year 2010 was confirmed by
telephone conversation with a staff person on the Albany-Dougherty Planning
Commission.
Comment 2 9: One PRP stated that the on-site worker scenario appears to
drive the risk assessment. The narrative seems to imply that the worker is
in the contaminated area for the full time at work. A more realistic
scenario could be a worker trespassing the area or mowing the grass or an
off-site youth visiting the site occasionally.
Response 29: The current use of the site is an operating welding supply
company. Although the facility does not use the west side of the building
(which is most highly contaminated) on a day-to-day basis at this time,
this area could be used at any time in the future resulting in unacceptabj^
risk to on-site workers.
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Comment 30: One PRP stated that the juvenile site visitor scenario seems
excessive, because site access is controlled.
Response 30: See response 27. In addition, site access is not controlled
during non-business hours.
IV. Concerns to be Addressed in the Future
No concerns to be addressed in the future were identified.
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APPENDIX B
CONCURRENCE LETTER
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Georgia Department of Natural Resources
205 Butler Street, S.E., Suite 1154 Atlanta, Georgia 30334
Joe D. Tanner, Commissioner
Environmental Protection Division
Harold F. Reheis, Director
404/656-2833 404/656-7802
April 29, 1996
Mr.
Acting Division Director
Waste Management Division
U.S. EPA, Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
RE: Record of Decision
T H Agriculture & Nutrition
NPL Site
Operable Unit Two (OU #2)
Dear Mr. Green:
The Georgia Environmental Protection Division (EPD) has reviewed the Record of Decision,
Summary of Remedial Alternative Selection for the T H Agriculture & Nutrition Site (Operable Unit Two)
in Albany, Georgia. EPD concurs with the selected remedy in which the major components include:
excavation of all soil contaminated with organics necessary to meet performance standards;
staging and preconditioning of soil for low temperature thermal desorption;
treatment of excavated soil by low temperature thermal desorption;
placement of treated, decontaminated soil back to the Site;
periodic sampling of treated soil during the treatment process to verify the effectiveness of the
remedy;
air monitoring to ensure safety of nearby residents and workers;
groundwater monitoring to ensure that metals contamination of groundwater is not migrating off-
site in concentrations which exceed groundwater protection standards; and
institutional controls such as deed restrictions to prevent residential use of the property and/or
groundwater where implemented under the Operable Unit 1 (OU#1) remedy.
If you have any questions, please contact Ned Emrick at (404) 656-7802.
Sincerely,
H
ld F. Refieis
Director
HFR/nce
R:\Ned\THRODLTR
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