United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EP A/ROD/R04-93/157
September 1993
PB94-964014
v°/EPA Superfund
Record of Decision
Helena Chemical Landfill, SC
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R04-93/157
3. Recipient's Accession No.
This and Subtitle
SUPERFUND RECORD OF DECISION
Helena Chemical Landfill, SC
First Remedial Action - Final
5 Report OH*
09/08/93
7. Authors)
a Performing Organization Rept No.
9. Performing Organization Name and Address
10 Project Taskwork Unit No.
11. Contrmct(C) or Grant(G) No.
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Raport A Period Covered
800/800
14.
15. Supplementary Notes
PB94-964014
ia Abstract (Limit: 200 words)
The 4-acre Helena Chemical Landfill site is located on the northern portion of the
13.5-acre Helena Chemical Company property in Fairfax, Allendale County, South
Carolina. Land use in the area is mixed commercial, industrial, agricultural, and
residential. A water supply well to the city of Fairfax supplies water to 2,300
residents, and is located 200 feet west of the property. Surface water at the facility
drains into a small ditch which subsequently drains into Duck Creek, a tributary
located northwest of the property that flows into the Cooswatchie River located to the
west of the property. In addition, several wetland areas occur in the northern portion
of the facility in close proximity to the former landfill. Prior to the 1960s, and
until 1978, the Helena Chemical Company and two previous owners manufactured liquid and
powdered insecticides onsite. The facility consists of three buildings: the north
warehouse, which was used to formulate liquid insecticides; the south warehouse, which
was used to formulate powdered insecticides; and the office. The former landfill is
located north of the north warehouse and was reportedly used for disposal of chemical
wastes. Several above-ground solvent tanks, which have since been removed, were used
to store solvents transported to the site by rail. Types of chemicals formulated or
stored onsite included pesticides, solvents, diesel fuels, and clays. In 1980, State
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Helena Chemical Landfill, SC
First Remedial Action - Final
Contaminated Media: soil, sediment, gw, sw
Key Contaminants: VOCs (benzene), other organics (pesticides), metals (chromium, lead)
b. Mentlfiers/Open-Ended Terms
c COSATl Field/Group
Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No-ofPagM
100
22. Price
(SeeANSt-Z39.1B)
See Instruction* on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R04-93/157
Helena Chemical Landfill, SC
First Remedial Action - Final
Abstract (Continued)
investigations regarding an onsite waste dump indicated high levels of various pesticides
at the site. In 1981, the State required Helena Chemical to provide additional information
regarding site activities. The State, EPA, and Helena Chemical conducted additional site
investigations from 1981 through 1992. These investigations confirmed the presence of
site-related pesticides in the soil and indicated the presence of pesticides in sediment,
debris, ground water, and surface water in the vicinity of the former landfill. Two
removal actions were conducted at the site during 1984 and 1992, and 500 and 1,000 yds^ of
contaminated soil, respectively, were removed to a permitted hazardous waste landfill.
This ROD addresses a first and final remedy for the remaining onsite contamination in the
soil, sediment, ground water, and surface water. The primary contaminants of concern
affecting the soil, sediment, ground water, and surface water are VOCs, including benzene;
other organics, including pesticides; and metals, including chromium and lead.
The selected remedial action for this site includes excavating approximately 20,000 yd^ of
contaminated soil and debris from the former landfill and areas adjacent to the northern
warehouse; treating the soil an debris using hydrolytic/photolytic dechlorination (HPD),
followed by ex-situ biodegradation; returning the treated soil and debris to the original
excavated areas; covering the treated soil with at least one foot of clean fill; providing
for a contingent remedy including low temperature thermal desorption, if treatability
studies indicate that the HPD/biological treatment cannot attain the soil remediation
goals; demolishing the former formulation buildings, if necessary, to allow for removal
and treatment of all contaminated soil; testing the demolished buildings to determine
appropriate handling and disposal options; mitigating any impact to wetlands; extracting
and treating contaminated ground water onsite to POTW pre-treatment requirements, with
discharge to the local POTW; and monitoring excavated and treated soil and ground water
(in-situ, as well as, extracted and treated) to ensure compliance with all performance
standards. The estimated present worth cost for this remedial action is $3,900,000.
PERFORMANCE STANDARDS OR GOALS:
The soil excavation standard is based on protection of human health and the environment
and is equal to 50 mg/kg total pesticides. Soil treatment standards are based on RCRA
LDRs and range from 66 ug/kg to 1,300 ug/kg. Chemical-specific ground water treatment
goals are based on SDWA MCLs, and include benzene 5 ug/1; chromium 100 ug/1; lead 15 ug/1;
and pesticides 0.002-3 ug/1.
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RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
HELENA CHEMICAL SUPBRFUND SITE
FAIRFAX, ALLENDALB COUNTY
SOUTH CAROLINA
PREPARED BY:
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
ATLANTA, GEORGIA
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DECLARATION FOR THE RECORD OF DECISION
SITE NAME AND LOCATION
Helena Chemical
Fairfax, Allendale County, South Carolina
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Helena Chemical Superfund Site (the Site) in Fairfax, South
Carolina, which was chosen in accordance with the the Comprehensive
Environmental Response, Compensation and Liability Act of 1980, as
amended by the Superfund Amendments and Reauthorization Act of 1986
and, to the extent practicable, the National Oil and Hazardous
Substances Contingency Plan (NCP). This decision is based on the
Administrative Record file for this Site.
The State of South Carolina concurs with the selected remedy.
Appendix B contains the letter indicating their concurrence.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action selected
in this Record of Decision (ROD) , may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE SELECTED REMEDY
This remedial action addresses onsite soil contamination, the
principal threat at this Site; as well as onsite and offsite
groundwater contamination.
The major components of the selected remedy include:
SOURCE CONTROL
D Excavation of contaminated surface and subsurface
soil, with verification sampling;
D Treatment of the contaminated soils by means of
hydrolytic/photolytic dechlorination and biological
degradation;
D Placement of the treated soils into on-Site excavations.
D Site re-grading to prevent uncontrolled storm-water
run off into waters of the State or the United States.
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GROUNDWATER
Extraction of contaminated groundwater from the surface
(shallow) aquifer;
Treatment and discharge of the treated groundwater to a
local Publicly-Owned Treatment Works (POTW).
MITIGATION FOR ADVERSE IMPACTS TO WETLANDS
D Mitigation for adverse impacts to environmental receptors
in accordance with regulatory guidelines established
under the authority of Section 404 of the Clean Water
Act.
SITE MONITORING
D Quarterly sampling of groundwater and nearby public water
supply to monitor the concentrations and movement of
contaminants in affected and potentially affected
aquifers.
CONTINGENCY REMEDY
D Low temperature thermal desorption (LTTD) is a
contingency remedy for soil treatment, to be implemented
should the chosen soil treatment technology prove
incapable of achieving performance standards.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost effective. This remedy utilizes permanent
solutions and alternative and/or innovative treatment technology to
the maximum extent practicable for this Site. The selected
groundwater remedy component satisfies the preference for
treatment. The selected remedy for source control and soil
treatment also satisfies the preference for treatment.
Since selection of this remedy will result in contaminated
groundwater remaining onsite above health-based levels until remedy
implementation is complete, a review will be conducted within five
years after commencement of remedial action to insure that the
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remedy continues to provide adequate protection of human health and
the environment .
Patrick M. Tobin
Acting Regional Administrator
Date
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TABLE OF CONTENTS
SECTION PAGE
1. 0 SITE LOCATION AND DESCRIPTION 1
1.1 Site Location 1
1.2 Site Description 1
1.3 Site Topography and Drainage 4
1. 4 Climate 4
1.5 Geology and Hydrogeologic Setting 5
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES . 6
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 8
4.0 SCOPE AND ROLE OF THIS ACTION WITHIN SITE STRATEGY 9
5 . 0 SUMMARY OF SITE CHARACTERISTICS 9
5.1 Site-Specific Geology and Hydrogeology 9
5 .2 Nature and Extent of Contamination 18
5.2.1 Surface and Subsurface Soils 20
5.2.2 Groundwater 27
5.2.3 Surface Water 34
6.0 SUMMARY OF SITE RISKS 34
6 .1 Contaminants of Concern 36
6.2 Exposure Assessment 49
6 .3 Toxicity Assessment 52
6.4 Risk Characterization 56
6.5 Environmental (Ecological) Risks 59
7.0 DESCRIPTION OF REMEDIAL ALTERNATIVES 60
7 .1 Alternative 1; No Action 63
7.2 Alternative 2; Landfill 63
7 .3 Alternative 3; Biodegradation 64
7.4 Alternative 4; HPD 65
7.5 Alternative 5; HPD/Biodegradation 66
7 . 6 Alternative 6; LTTD 67
8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 68
8.1 Criteria for Comparative Analysis 68
8.1.1 Threshold Criteria 68
8.1.2 Primary Balancing Criteria 68
8.1.3 Modifying Criteria 69
8.2 Comparison of Alternatives 69
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Table of Contents (cont'd.) ii
SECTION PAGE
9 . 0 THE SELECTED REMEDY 70
9.1 Description of Selected Remedy 71
9.1.1 Source Control 71
9.1.2 Ground Water Remediation 72
9.1.3 Wetlands Mitigation 73
9.1.4 Compliance Testing 74
9.1.5 Contingency Remedy 75
9.2 Applicable or Relevant and Appropriate Rrequirements
(ARARs) 75
9.2.1 Applicable Requirements 75
9.2.2 Relevant and Appropriate Requirements 76
9.2.3 Criteria "To Be Considered" 79
9.3 Performance Standards 80
9.3.1 Excavation Standards 80
9.3.2 Treatment Standards 80
9.3.3 Ground-Water Remediation Stds 81
9.3.4 Storm Water Discharge Stds 81
9.3.5 Wetlands Mitigation 81
10.0 STATUTORY DETERMINATIONS 82
APPENDICES
APPENDIX A - RESPONSIVENESS SUMMARY
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LIST OF FIGURBS iii
FIGURE PAGE
- 1 Location Map 2
2 Site Layout Map 3
3 Monitoring Well and Soil Boring Locations 10
4 Pesticides in Surficial Soils 21
5 Soil Pathway Exposure Assumptions 46
6 Ground-Water Pathway Exposure Assumptions 48
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LIST OF TABLES iv
TABLE PAGE
-1 Phase II Slug Test Results ; 14
2 Hydraulic Gradients 14
3 Phase III Slug Test Results 16
4 Preliminary Contaminants of Concern 19
5 Phase II Pesticides in Surface Water & Sediment 33
6 Pesticides in Soils 37
7 Semi-Volatiles in Soils 39
8 Volatiles in Soils 40
9 Summary of Ground-Water Contamination 41
10 Phase III Pesticides in Surface Waters & Sediments...43
11 GW Contaminant Exposure Data 50
12 Soil Contaminant Exposure Data 51
13 Summary of GW Exposure Risk 53
14 Summary of Soil Exposure Risk 54
15 Summary of Health-Based Risk Criteria 55
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DECISION SUMMARY
HELENA CHEMICAL SUPERFDND SITE
_^ FAIRFAX, ALLENPALB COUNTY, SOUTH CAROLINA Page 1
1.0 SITE LOCATION AND DESCRIPTION
1..1 SITE LOCATION
Helena Chemical Company, Fairfax, South Carolina is located on 13.5
acres adjacent to Highway 321 in Allendale County, South Carolina.
Figure 1.1 is a vicinity map. Located at the facility is a former
landfill which contains pesticide residues and other waste
materials generated on-Site. The former landfill .occupies
approximately four (4) acres on the northeast portion of the
Fairfax property. Figure 1.2 is an approximately scaled survey of
the facility showing the location of the landfill. The site is
encircled by a chain link security fence topped with barbed wire.
A city water well that is utilized by a population of approximately
2,300 is located 200 feet west of the property.
1.2 SITE DESCRIPTION
Three buildings exist on the Fairfax property; the north warehouse,
the office, and the south warehouse. The north warehouse, which
was once utilized to house the liquid insecticide formulation
operation, is currently used to store various pesticides,
herbicides, and fertilizers which are sold to farmers. There are
several significant features of the liquid formulation building
which were focal points of the investigation. Two 22,000 gallon
above ground solvent tanks were once located near the north
entrance to the "kettle room" in the former liquid formulation
building. These tanks were present prior to Helena's occupancy of
the property. Solvents used in the formulation process were
delivered to the site by rail car via a rail spur which was used to
serve the facility. The solvents were offloaded by pressurizing
the tanker cars and pumping the solvents through product lines
which ran under the formulation building to the storage tanks. The
storage tanks were located in the area identified as the "tank
farm" on Figure 2. The solvents were then gravity fed to the
kettle as needed. The solvent tanks are no longer present;
however, the concrete slab on which the tank saddles rested still
exists. The remains of a tank farm which was used to store the
technical grade pesticide compounds are located on the east side of
the liquid formulation building. Only the concrete pads on which
the tanks rested and a retaining wall remain. During the Remedial
Investigation (RI) a drain pipe which originates inside the
warehouse was observed and is suspected to have been used to
discharge effluent onto the ground surface in an area northwest of
the structure. The south warehouse where powdered insecticides
were formulated is no longer in use. A septic tank system which
serviced the property is located between the north liquid
formulation building and the office.
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Figure 1; Helena Location Map
^.C .
Helena Ch«mic«l J
Fairfax Site
.' • ^ /./
f /
CONTOUR DVTERVAL 1.5 METERS \ )
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Figure 2; Helena Site Map
CITY OT FAIRFAX
MUNICIPAL VEIL
- TREE LINE
- FENCE
APPROXIMATE
PROPERTY BOUNDARY
— — - FORMER STREAM
CHANNEL
INTERMITTENT STREAM
- RAILROAD SPUR
APPROX. 13.5 ACRES
BIQREHEDIATION
PIUJT STUDY
TEST rni«
FORMER LOCATION
OF HOUSE
FORMER LOCA
OF SOLVENT \ APPROX,
\ STORAGE TANKS \ LOCATION
OF FORMER
LANDFILL
\ UNDERGROUND
PIPING
APPROX SEPTIC
TANK LOCATION
PAH ROAD
Envlronnental ana Safety Designs. Inc.
FIGURE 1.8
FACILITY SKETCH
HELENA CHEMICAL CD.
FAIRFAX, SOUTH CAROLINA
U.S. HVY 331
sitra mas oe /emoxm jwx •rmart-na
DWG DATE: 03/29/92 I DWG NAME:HELS1T3
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Located northwest of the north warehouse are the remains of a house
that burned sometime prior to 1988. The house belonged to the
previous property owner, Charles Blue.
According to City of Fairfax Water Department records, a 12" water
main constructed of cast iron extends across the site between the
north warehouse and the former landfill. The water line trends in
a general east-west direction and is reported to have been
installed approximately ten years ago.
Between the years of 1971 and 1978, Helena used the Fairfax
facility for the formulation of liquid, and some dry, agricultural
insecticides. Prior to the ownership by Helena Chemical Company
(beginning in 1971), two other chemical companies operated at the
Fairfax facility: Atlas Chemical Company, owned by Billy Mitchell
(prior to the mid 60's), and then Blue Chemical Company, owned by
Charles Blue (mid 60's through 1971). Both Atlas Chemical Company
and Blue Chemical Company utilized the Fairfax facility for the
formulation of insecticides. Chemicals formulated and/or stored at
the facility prior to Helena's ownership include: DDT, aldrin,
toxaphene, disulfoton, dieldrin, chlordane, BHC (benzene
hexachloride), and ethoprop (Mocap). The Fairfax facility is
presently being operated as a retail sales outlet and warehouse for
agricultural chemicals. Chemicals used in the previous formulation
of insecticides by Helena at the Fairfax facility 'include:
toxaphene, methyl parathion, EPN (ethyl p-nitrophenyl
thionobenzene-phosphonate), and disulfoton. In producing the
insecticides, the chemicals were formulated as mixtures with other
ingredients including diesel fuel, aromatic solvents, and clays.
1.3 SITE TOPOGRAPHY AND DRAINAGE
The local topography of the Fairfax area exhibits little relief.
The Helena Chemical property slopes slightly to the north. North
of the property is a topographically low area that collects surface
water during period of high rainfall. Additionally, surface water
from the facility drains into a small ditch that parallels the
property to the northwest. This ditch carries the water to Duck
Creek, a tributary located northwest of the property, which in turn
flows into the Coosawatchie River located to the west of the
Fairfax property. The creek and the river are located within a
three (3) mile radius of the Site.
1.4 CLIMATE
The relatively temperate climate of Fairfax is typical of the South
Carolina coastal plains region. This is largely due to the close
proximity of the Atlantic Ocean and its warm Gulf Stream current
flowing northward near the southeastern border of the state
creating a warming effect on the region.
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Data provided by the South Carolina State Climatology office
indicated the annual mean temperature in the vicinity of Fairfax is
65.1°F. The mean annual precipitation of Fairfax is approximately
47.95 inches. These figures are based on data gathered at Hampton,
S.C. which is the closest reporting station to Fairfax (a reporting
station has recently been established in Allendale, S.C.; however,
at the present time insufficient data has been gathered to
calculate the annual means).
Prevailing winds in the Fairfax area exhibit seasonal variations.
In the spring, southwest winds are predominate; summer, south and
southwest winds prevail; autumn, prevailing winds are from the
northeast; and in winter, northeast and southwest winds have close
to the same frequency. Average wind speeds throughout the year
range from 6 to 10 miles per hour (Climate Report No. G5, S.C.
State Climatology Office, May 1990).
1.5 GEOLOGY AND HYDROGEOLOGIC SETTING
Site specific geological and stratigraphic data were developed
during the installation of test borings and monitoring wells.
Three distinct stratigraphic units were observed in the upper 145
feet of unconsolidated sediments encountered at the site, and a
fourth may be present.
The lowermost stratigraphic unit identified during the
investigation was a gray to green, fine grained clayey sand
interbedded with clay laminae and numerous shell fragments. The
unit was moist, but did not exhibit the saturated properties as
seen in the overlying sands. Based on lithology, this unit is
presumed to be the upper portion of the McBean/Santee Limestone
Formation. The observed thickness of this unit was approximately
45 feet. The maximum thickness of this formation was not determined
during the investigation.
Overlying what is presumed to be the McBean Formation is a
predominantly yellow to gold, fine to coarse sand. This unit is
also characterized by numerous shell fragments interspersed among
the sand grains. These sands are thought to be a member of the
Barnwell Group. The Barnwell Group is comprised of the Tobacco
Road Sand and the Dry Branch Formation. Recent investigations have
indicated that the contact between the formations is a one to three
foot thick layer, of coarse sand and gravel. This gravel layer was
not positively identified in any of the borings; therefore,
distinct facies changes were not stratigraphically identified
during the RI.
Overlying the sands of the Barnwell Group is a light gray and green
medium sand which in some locations graded to a coarse tan sand
with some pebbles and shell fragments. The lower contact between
the formations was distinguished by a silicified shell hash in
other locations. The sands graded in a fining upward sequence to a
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very fine to medium grained sand intermingled with a dense red,
orange, and gray mottled clay. These sediments are characteristic
of what is thought to be the Duplin Formation.
Based on the boring logs from MW-12, MW-14, MW-19 and MW-20, there
appears to be a lateral facies change to the north of the landfill.
Surface soils north of the landfill consist of a dark gray, dense
clay. Due to limited information, it is unclear whether the
detrital sand underlying this area is a continuation of the Duplin
or if a portion of the Duplin has been eroded and the sand a
product of more recent depositional processes.
The highest yielding aquifer in the area surrounding Fairfax is
found within the sands of the Cape Fear, Middendorf, and Black
Creek Formations. These regional aquifers are some of the most
permeable units in the stratigraphic column, providing large
quantities of water for both municipal and private use.
The high clay content of the Black Mingo Formation results in
relatively low permeability. This has led to the designation of
the formation as an aquitard or aquiclude. Some small domestic
wells, however, may be utilizing water from more permeable portions
of the Black Mingo.
Although previous studies have indicated the McBean was not thought
to be important as a public or commercial source, member beds
within this formation produce sufficient water for use. The Town
of Fairfax south municipal well is screened within the
McBean/Santee Formation. A pumping test on the municipal well
conducted by the city engineers indicated a transmissivity of 500
ft.Vday at a pumping rate of approximately 298 gpm. The overlying
sands of the Barnwell Group have been described as a relatively low
permeability, low yielding aquifer that is used primarily for
domestic water supply. The Barnwell underlying the site, however,
is recognized as a highly permeable, saturated sand.
Previous investigations tentatively identified the presence of the
Cooper Marl at the Site. Recent investigations, however, have
indicated that the surficial sediments are characteristic of the
Duplin Formation of Miocene age. The upper portion of the Duplin
Formation appears to be acting as an aquitard at the Site.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
Several companies have operated pesticide formulation facilities on
the Site currently owned by Helena. Prior to the mid-60's, the
Site was owned by Atlas Chemical Company, and from the'mid-60's
until 1971 by Blue Chemical Company. Between the years 1971-1978,
Helena Chemical company used the Site for the formulation of both
liquid and dry agricultural insecticides. Chemicals that have been
stored and/or formulated at the facility during its active life
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include DDT, aldrin, toxaphene, disulfoton, dieldrin, chlordane,
benzene hexachloride (BHC), ethoprop, methyl parathion and ethyl p-
nitrophenyl thionobenzene-phosphonate (EPN). During the
formulation process these chemicals were mixed with carrying agents
including diesel fuel, volatile organic chemicals and adsorbent
materials.
The first regulatory actions taken with respect to the Helena Site
occurred in November, 1980, as a result of reports by a former
employee of Helena and a newspaper reporter that a waste dump was
being operated on the Site. The Site was investigated at that time
by the South Carolina Department of Health and Environmental
Control (SCDHEC). Numerous soil samples were collected and
analyzed in December, 1980. High levels of various pesticides,
including aldrin, BHC isomers, chlordane, dieldrin, disulfoton,
endrin and toxaphene were detected in these samples. As a result
of these findings, SCDHEC requested that Helena provide further
information regarding activities at the Site, including chemicals
handled as part of the operation, waste disposal practices and
other pertinent information with respect to past and present Site
activities.
SCDHEC issued a Notice of Violation to Helena in July, 1981, for
the operation of a waste disposal facility in violation of
applicable South Carolina regulations. Negotiations between SCDHEC
and Helena resulted in the issuance of Administrative Consent Order
No. 81-05-SW on October 1, 1981. In compliance with the terms of
this Consent Order, Helena conducted investigations at the Site
lasting from October, 1981, to July, 1982. The results of these
studies indicated that surficial soils were heavily contaminated
with pesticides, including those identified in the earlier sampling
described above. The results of analyses of ground-water samples
obtained as part of this investigation were contradictory; the
positive results reported from the first sampling event were not
confirmed in samples taken at that time or in subsequent sampling
events. Surface water samples, taken from water standing in the
wetland areas in the northern portion of the Site, were found to be
heavily contaminated with site-related pesticides.
Helena prepared a plan for site remediation which was submitted to
SCDHEC for review, and, under the terms of an amendment to
Administrative Consent Order No. 81-05-SW, dated March 12, 1984,
remediation efforts were conducted that consisted mainly of the
removal of contaminated soils to a permitted hazardous waste
landfill.
In 1985, EPA, in conjunction with SCDHEC, conducted a Site
Screening Investigation at the Helena Chemical Site in order to
prepare a Hazard Ranking System (HRS) package for the Site in order
to determine whether the Site should be included on the National
Priorities List (NPL) . The HRS ranking was completed in June,
1987, and the Helena Site was proposed for listing in June, 1988.
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8
The Site was listed on the NPL in February, 1990.
In April, 1989, an Administrative Order by Consent (AOC) was
jointly developed, negotiated and agreed to by EPA arid Helena
Chemical Company. Under the terms of this AOC, Helena agreed to
conduct a Remedial Investigation (RI) and Feasibility Study (FS) at
the Site under the oversight of EPA. The purpose of the RI/FS
process was to develop an appropriate remedy for the Site as
required by the National Contingency Plan (NCP). Helena retained
the services of Environmental Safety and Designs, Inc. (ENSAFE) , of
Memphis, Tennessee as their contractor to conduct the RI/FS. RI
field activities began in May, 1989, and were completed in April,
1992.
Two removal actions for contaminated soils have taken place at the
Site. In addition to the removal of approximately 500 cubic yards
of contaminated material conducted by Helena in March, 1984, as
discussed above, in April, 1992, approximately 1000 cubic yards of
contaminated soils were also removed by Helena under the oversight
of EPA and likewise transported to a secure hazardous waste
landfill.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Initial community relations activities at the Helena Chemical NPL
Site included development and finalization of the Community
Relations Plan in December 1989. An information repository was
established at the Fairfax City Hall in January 1990.
A "kickoff" fact sheet announcing the start of the RI/FS was issued
in April 1990. On April 19, 1990, EPA held a public meeting at the
Fairfax Community Center to present the Agency's plans for the
RI/FS. The meeting was attended by several local citizens,
representatives of Helena Chemical, elected local officials and was
covered by local newspapers. EPA's presentation to the public
included information on how to participate in the investigation and
remedy selection process under Superfund. At the meeting, several
questions were asked and a fair amount of interest was expressed by
the community.
Following completion of the FS, a second public meeting was held on
May 27, 1993, to update the public on the RI findings to date, and
to present the proposed plan for the remedial actions at the Site.
The meeting was attended by only a few members of the public, with
no press coverage. At this meeting, the primary concerns expressed
by the public involved the threat posed by contaminated ground
water to the nearby public supply well.
Proposed Plan fact sheets were distributed on May 18, 1993. An
advertisement was published in two of the local newspapers on the
same date. Both the advertisement and the fact sheet highlighted
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the Public Comment period extending from May 18, 1993, until June
17, 1993.
At the Proposed Plan public meeting on May 27, 1993, EPA presented
the Agency's selection of Preferred Alternatives for addressing
soil, sediment, surface water and groundwater contamination at the
Site. Public comments and questions are documented in the
Responsiveness Summary, Appendix A.
4.0 SCOPE AND ROLE OF THIS ACTION WITHIN SITE STRATEGY
The purpose of the remedial alternative selected in this ROD is to
reduce current and future risks at this Site. The remedial action
for soil will remove current and future health threats posed by
contaminated shallow soil and will prevent leaching of the soil
contaminants to groundwater. The groundwater remedial action will
remove future risks posed by potential usage of contaminated
groundwater. It will also serve to remove the threat to surface
water by reducing the concentrations of surficial aquifer
contaminants reaching nearby surface water systems. Wetlands
mitigation will address the unacceptable levels of environmental
risk posed by contamination of sediments and surface waters in on-
site and adjacent jurisdictional wetlands. This is the only ROD
contemplated for this Site.
5.0 SUMMARY OF SITE CHARACTERISTICS
The RI investigated the nature and extent of contamination on and
near the Site, and defined the potential risks to human health and
the environment posed by the Site. A supporting RI objective was
to characterize the Site-specific geology and hydrogeology. The
main portion of the RI was conducted from May 1989 through April
1992. Onsite locations of soil borings, soil samples, and monitor
wells are shown in Figure 3.
5.1 SITE SPECIFIC GEOLOGY AND HYDROGEOLOGY
The local hydrogeologic characterization discussed below was
derived from RI data, including falling head permeability tests,
grain size analyses, slug tests, piezometric surface maps, and
numerous boring logs. In addition, the Barnwell Group aquifer
system was monitored to determine if the City of Fairfax Municipal
well affected the aquifer during pumping and non-pumping events as
described below.
For the purpose of the RI, the hydrogeologic assessment
concentrated primarily on the uppermost aquifer at the Site. The
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10
Figure 3; Monitoring Wells and Soil Borings
100
feet
HIGHVAY
S-13
LEGEND
- TREE LINE
• - fENCE
APPROXIMATE
PROPERTY BOUNDARY
—- —- - FTIRMER STREAM
CHANNEL
INTERMITTENT STREAM
O MV-t - MONITORING WELL LOC.I
BH/HCB-* - BORING
UFMXDC. LOCATUkO
CSX RAILROAD
HV-26.» MV-gS
U.S. HVY 331
Environnen-tal and Safety Designs. Inc.
sun* racrr fle
FIGURE 2.4
BORING AND MONITORING
VELL LDCATIDNS
HELENA CHEMICAL CO.
FAIRFAX, SOUTH CAROLINA
DWG DATE:03/29/92 I DWG NAME:HELFAX28
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11
uppermost aquifer occurs within sands of the Barnwell Group and the
lower portion of the Duplin Formation. Member beds within these
formations may exhibit minor facies changes; however, they are
considered to be hydraulically connected.
Beneath the site, the upper portion of the Duplin Formation at
times demonstrates the hydrogeologic characteristics of an
aquitard. High clay content and corresponding low permeability are
two characteristics that limit vertical groundwater flow in this
unit. Grain size analyses and boring logs indicate that the Upper
Duplin has a high silt and clay content. The average silt and clay
fraction from nine (9) soil samples was 33 percent. The samples
averaged 90 percent finer than the upper limit designation- for fine
sand. These analyses suggest that the Upper Duplin is a silty,
clayey very fine sand with the capability to retard groundwater
flow.
Estimates of permeability were determined with Shelby tube samples
collected from the Upper Duplin. Eight undisturbed soil samples
were obtained from MW-4, MW-8, MW-10, MW-14, MW-20, MW-22, MW-24,
and MW-26 by pushing a thin walled Shelby tube 12-24 inches into
the soil. Rigid wall falling head permeability tests were
conducted on these samples in accordance with the Corp of Engineers
method EM 110-2-1906. The resulting permeability values were
indicative of an aquitard, and they highlight the capability of
this unit to restrict near surface groundwater movement. Two
additional thin wall Shelby tubes were collected from the clay cap
overlying the closed landfill, and these soil samples also exhibit
low permeabilities.
The upper aquifer system appears to be comprised of, in descending
order, the lower sands of the Duplin Formation, the Tobacco Road
Sand Formation, and the Dry Branch Formation. These units exhibit
saturated conditions and appear hydraulically connected in the
study area. Although there are a few thin clay/silt, laminae
present in the upper 30 feet of the unit the limited thickness and
lateral extent of these laminae suggest that they do not impede
vertical groundwater flow. Well logs indicate these sands to be
vertically uninterrupted from an average depth of approximately 12
feet to a depth of at least 90 feet below ground surface. The
overall thickness of the uppermost aquifer is estimated to be
approximately 80 feet.
The Fairfax municipal well log included in the RI describes a
yellow and gray clay from 90 to 103 feet. During the installation
of soil boring HCB-5 on the north end of the Helena property a dark
gray to green, fine grained clayey sand interbedded with clay
laminae and numerous shell fragments was identified from
approximately 95 to 145 feet below ground surface. The unit was
moist, but did not exhibit the saturated properties as seen in the
upper Eocene sands and appeared relatively impermeable. Based on
the aforementioned lithological descriptions, this unit is thought
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12
to be representative of the upper section of the McBean Formation.
Defining the lateral and vertical extent of this unit was beyond
the scope of this investigation. The drillers log from the City of
Fairfax municipal well, however, indicates the presence of
limestone at depths of 260 to 347 below ground surface. The
limestone may be representative of the Santee which varies
considerably in the area and may signify actual lateral facies
changes between the downdip Santee and the updip McBean.
Water level measurements conducted during the RI indicate that
groundwater flow directions in both the shallow and deep portions
of the upper aquifer exhibit seasonal variation. Summer water
levels indicate that shallow flow is directed to the
south-southwest. The piezometric diagram of water levels taken in
April 1991, however, reveals directional components to the south,
east and southeast. Similarly, but to a lesser extent, groundwater
flowing in the deeper portions of the aquifer exhibits variation in
direction throughout the year. Although deep well control is
limited, flow direction in the summer is directed to the southwest.
This corresponds with shallow flow directions. The data for April
and September, 1991, indicate that the deeper groundwater flow was
toward the south-southeast.
The lack of vertical groundwater flow is apparent from the minimal
differences in water level between wells in the nine (9)
deep/shallow well clusters at the site. From the eight (8) water
level measuring events that have been conducted, the maximum
downward vertical gradient was 0.018 feet per foot between MW-1 and
MW-2 for July, 1990. The minimum was 0.0001 feet per foot between
MW-19 and MW-20 for October, 1991. The average downward gradient
of the nine (9) well clusters for the eight (8) measurement events
was 0.002 feet per foot.
Interestingly, the upper aquifer appears to change from unconfined
to confined conditions at different times throughout the year. The
July, 1990 water levels for most of the wells on site were from 2
to 2.5 feet below the top of the confining portion of the Duplin
formation. This suggests unconfined conditions may exist for at
least a portion of the year. Conversely, confined conditions were
encountered in the spring of 1991 when water levels were well above
the contact between the more permeable sands of the upper aquifer
system and the overlying less permeable clayey sands. This
artesian condition was further supported by groundwater flowing out
the top of MW-14 in March, 1991. One simple explanation for this
phenomenon is associated with changing water levels in the upper
aquifer.
During the dryer portion of the year (July and August), water
levels fall below the base of the clayey sands of the Duplin
Formation. This effectively dewaters the upper portion of the
aquifer. Dewatering is a characteristic behavior of unconfined
aquifers. During wet periods when water levels rise above the
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13
contact between the permeable sands and the low permeability clayey
sand within the Duplin, the aquifer exhibits confined conditions.
To obtain estimates of groundwater velocity, several slug tests
were conducted at the site on March 4 and 5, 1991. Testing
consisted of rising and/or falling head slug tests for MW-2, MW-4,
MW-6, MW-8, andMW-10.
Rising and falling head slug tests were performed to characterize
the hydraulic conductivity (K) of aquifer materials. Slug tests
were initiated during Phase II-B and Phase III of the RI. Before
each slug test was initiated, the static water level in'the well
was measured using an electronic water level indicator. A
stainless steel cylinder of known volume was then introduced
"instantaneously" into the well, at which time, the water level and
the time were recorded. Periodically, water level/elapsed time
measurements were made as the head fell back to the original level.
Similarly, rising head slug tests were preformed by removing the
slug and recording water level/elapsed time measurements as the
head rose back to normal. For slug tests, the time required for
the water level to return to normal is a function of the hydraulic
conductivity (K) of the aquifer.
For this investigation, an In-Situ, HERMIT 1000B data logger and a
50 psi pressure transducer were used to record water level/elapsed
time measurements during each slug test. For purposes of graphing
data, the instrument was programmed to record measurements on a
logarithmic time scale. The slug consisted of a five-foot (5)
long, 1.66-inch diameter stainless steel cylinder with a stainless
steel ring welded on one end. A teflon coated stainless steel cord
tethered to the ring served to suspend the slug in the well just
above or below the water level. At the beginning of each test, the
data logger was activated the instant the slug was either lowered
into or removed from the water.
The hydraulic conductivity (K) calculated from each slug test is
presented in Table 1 below. The methods used to arrive at these
values are discussed below. Rising and falling head slug test data
from each well were graphed as time (elapsed) versus Log(H/Ho) in
order to create a straight line. Log(H/Ho) is the Log base ten of
the change in head divided by the initial head. Hydraulic
conductivity (K) was computed from these plots using a method
developed by Hvorslev.
This method utilizes a variable known as the basic time lag in an
equation that calculates the hydraulic conductivity. Hvorslev
contends that the basic time lag is the time at which the head
ratio (H/Ho) equals 0.37. Log (H/H<,) was plotted against time on
standard graph paper. A corresponding basic time lag was taken
from the time scale at the bottom of each diagram, and then
calculated using an equation for hydraulic conductivity.
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14
Well
MW2
Falling
2.5
MW4
Falling
1.23
kmax = 9.5
ft/day
MW6
Falling
9.2
kmin =1.23
ft/day
MW6
Rising
4.6
kave =5.3
ft/day
MW8
Rising
9.5
MW10
Falling
4.2
MW10
Rising
5.6
The Hvorslev equation used in these calculations was developed for
confined conditions with the assumption that the test well is
screened in the upper portion of a permeable unit that is overlain
by an impermeable unit. This scenario approximately describes
Fairfax site conditions.
To estimate groundwater velocity, the hydraulic gradient was
derived from the piezometric data generated during the RI. The
maximum and minimum slopes between contour lines were measured
directly from the isocon maps developed from this data, and these
values are shown in Table 2.
Shallow Wells
Max
0.0026
Min
0.00033
Deep Wells
Max
0.0035
Min
0.0007
Estimates of the shallow horizontal groundwater velocity (V) were
calculated from the following formula:
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15
V = Ki/n
Where:
V = groundwater velocity
K = hydraulic conductivity
i = hydraulic gradient
n = porosity
A porosity (n) of 25 percent was chosen based on estimates for
medium-to coarse-grained, poorly sorted sand aquifers. The maximum
and minimum estimated velocities were calculated using the maximum
and minimum hydraulic conductivities and corresponding hydraulic
gradients in the formula.
Estimated Shallow Groundwater Velocity V (ft/day)
Vmax = (Kmax * imax)/n =0.1 ft/day
Vmin = (Kmin * imin)/n = 0.0016 ft/day
Additional slug tests were completed upon completion of Phase III
field activities. With the following exceptions, Phase III slug
tests were conducted in a manner similar to the Phase II-B slug
tests:
Phase III tests incorporated a different type of slug than
Phase II-B. Instead of using the stainless steel cylinder,
one gallon of deionized water was "instantaneously" introduced
in the well.
Only falling head tests were conducted as water was not
"instantaneously" removed from the well.
For the Phase III investigation, an In-Situ HERMIT 2000 data logger
and a 20 psi pressure transducer were used to record water
level/elapsed time measurements during each slug test. A one
gallon jug of deionized water was used to slug each well. At the
beginning of each test, the data logger was activated the instant
that water was poured into the well.
Data reduction and compilation were conducted using the same
equations and calculations described for the Phase II-B slug tests.
The Phase III slug test graphs are presented in Appendix C and
Table 3 summarizes the hydraulic conductivity values derived from
the graphs.
To determine if the aquifer supplying the Fairfax municipal well is
separate from the shallow aquifer beneath the site, two aquifer
communication tests were conducted the week of November 11, 1991.
The City of Fairfax public works department provided - full
cooperation during the tests.
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16
MW5
Falling
10.04
MW15
Falling
3.23
MW17
Falling
3.15
The first test involved pumping the city well for three 1-hour long
intervals separated by nonpumping periods of approximately 1-hour
in length. This test was designed to approximate the normal
operating conditions of the city pump system. During the test,
water levels were monitored in three observation wells (MW-5,
MW-15, and MW-17). Data from this test were inconclusive because
identifiable trends did not develop from short duration pumping.
The second test was conducted to investigate what effects might
result from pumping the city well for longer than one hour. Pumping
duration for the second test lasted approximately 5.5 hours and
MW-5, MW-15, and MW-17 served as observation wells again. With a
pumping duration of 5.5 hours, this test was never designed or
intended to be a constant rate aquifer test.
A Hermit 2000 data logger with three pressure transducers and a
barometric pressure probe were used during each test. Each
observation well had one of the pressure transducers-monitoring
water level fluctuations. The barometric probe was placed on the
ground to measure changes in barometric pressure during the tests.
The data logger recorded measurements from the four transducer
inputs simultaneously and on five-minute intervals during pumping
and nonpumping events.
For the second test, the data logger was activated approximately
17.5 hours before the city well pump was started to investigate
local water level trends. The static water level in each
monitoring well at the time the data logger was activated became
the zero reference level for that well. Throughout the recording
period, the data logger recorded water level changes from this
original reference level.
Prior to the test, the city water tank was allowed to -drain to
approximately 1/3 capacity. Because some water had to remain in
the tank to maintain water pressure, this was the lowest water tank
level that Fairfax water supply officials would permit. Pumping at
390 gallons per minute (gpm), it took the city water supply well
approximately 5.5 hours to refill the water tank during the test.
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17
Drawdown values from each well were plotted against time to
investigate water level trends. Drawdown is represented as a
positive deflection from the original zero reference level in the
data. Water levels recorded above the original reference level
were recorded as negative drawdowns. Similarly, a rise in water
level is represented by a negative deflection. In all three
monitoring wells there was a general downward trend in water levels
with time. This may be the result of increasing barometric
pressure at the site. When the water level graphs were compared to
the barometric pressure graph, however, the graphs show a definite
change in water level with respect to pressure along the time axis.
The difference in drawdown changes may be due to the difference in
water level elevation.
Interestingly, water levels in each observation well rose abruptly
when the pump was turned on. Although immediate, the maximum rise
in any of the wells was slightly above 0.1 feet. While the pump
was running, water levels fluctuated greatly. When the pump
stopped, water levels dropped to levels corresponding to prepumping
trends.
This phenomenon of abrupt rise and fall of water levels induced by
pumping is common in confined and semiconfined aquifers. The
occurrence is attributed to the elastic properties of aquifer
materials (Lohman, 1972} . When the hydraulic pressure in an
artesian aquifer is reduced from pumping, the aquifer matrix
compresses to compensate. This matrix compression is physically
manifested as a slight net reduction in the thickness of the
aquifer. When pumping is halted, the aquifer matrix elastically
rebounds and the original aquifer thickness is recovered.
Ultimately, what appears to be a rise and fall in water levels may
actually be a decrease and increase in the thickness of the
aquifer. During the test, as aquifer thickness changed, the ground
surface, well casings, and the transducers attached to the casings
were lifted or lowered with respect to the nearly static water
level. These reactions were recorded by the transducers as changes
in water level.
With regard to communication between the deep city water supply
aquifer and the shallow aquifer beneath the site, the results of
this test are inconclusive. No large scale effects (obvious
drawdown) from pumping were observed in any of the monitoring wells
over the relatively short pumping duration used in this test. A
much longer pumping duration (24-hours or more) may be necessary to
investigate whether the observed phenomenon is the result of a
hydraulic connection between the two aquifers.
While evaluating the results of this pump test, however,
consideration should be given to the actual city pump system
configuration. According to Fairfax water supply officials, the
city pump rarely runs longer than 1/2 an hour at a time.
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18
Therefore, the pump test duration of 5.5 hours created much more
stress on the aquifer than normal pumping conditions would create.
Even though greater stress occurred during this test, no excessive
drawdowns were observed in the monitoring wells.
Given the uncertainty associated with the pump test already
conducted and the possibility of communication between the shallow
aquifer and the production zone of the City well, EPA believes that
further pump tests are warranted. The details by which additional
pump tests will be conducted will be determined during the Remedial
Design review process.
5.2 NATURE AND EXTENT OF CONTAMINATION
Environmental contamination at the Site can be summarized as
follows:
1) Organic and inorganic constituents of concern have been
identified in the various media. The primary
constituents of concern at the Site include: aldrin,
alpha-BHC, beta-BHC, delta-BHC, gamma-BHC, DDT, DDD, DDE,
dieldrin, endosulfan, endrin, endrin ketone, toxaphene,
endosulfan sulfate, disulfoton, benzene, lead and
chromium. Table 4, reproduced from the RI, identifies
the preliminary contaminants of concern for the Site.
2) Surface and subsurface soils throughout the Site have
been affected by past waste disposal activities. The
highest levels of contamination are found in the vicinity
of the former liquid formulation building now used as a
warehouse, in the vicinity of the old landfill, and near
the southernmost building on the Site in an area where
transhipments of materials from railroad cars occurred.
3) Ground waters in the aquifers immediately underlying the
Site have been affected by waste disposal activities at
the Site. The ground waters underlying the Site are
considered to be Class IIB ground waters under the draft
EPA Guidelines for Ground-Water Classification,
indicating that they are a potential source of public
water supply. These ground waters are also classified as
Class GB ground waters under South Carolina regulations.
The ground water has been contaminated to levels that
render it a threat to public health should it ever be
used for potable water supply and which exceed state
ambient standards for Class GB ground waters. Ongoing
sampling has to date revealed no site-specific
contamination in the nearby municipal water supply well.
4) High levels of contamination remain in soils and waste
materials in the old landfill located in the northern
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19
5)
portion of the Site. These soils and waste materials are
likely to be a continuing source of ground-water
contamination.
Surface water and sediments in on-site wetlands and
drainage pathways have been affected by past waste
disposal activities. Pesticide concentrations in samples
taken from on-site surface waters exceeded criteria that
'ft , V-,
SOIL/SEDIMENTS
Dieldrin
Endosulfan
Endrin Ketone
4,4'-DDT
Disulfoton**
Tributylphosphorotrithioate
(TBPT)**
Toxaphene
Aldrin
Endosulfan Sulfate
Endrin
Methoxychlor
4,4'-DDE
4,4'-DDD
BHC (a, fi, A and gamma)
ORODNDWATER
Benzene
Aldrin
Endosulfan II
Toxaphene
DDT (plus DDE & DDD)
BHC (a, E, A and gamma)
Dieldrin
Endrin
Endrin Ketone
Heptachlor Epoxide
Disulfoton
TBPT
Lead
Chromium
SURFACE WATER
BHC (fi, A)
Dieldrin
Endrin Ketone
are protective of aquatic life. Sediments in the on-site
wetland areas were found to be contaminated with site-
related pesticides at levels that are likewise likely to
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20
have an adverse impact on indigenous aquatic life.
6) Background and on-site air sampling indicates that local
ambient air has not been affected by past waste disposal
activities.
5.2.1 Surface and Subsurface Soils
The results of the field investigation identified varying
concentrations of polychlorinated pesticide compounds and minor
quantities of volatile organics in shallow surface soils (0 to 3
feet) . Soils from the 1 to 3 foot interval would normally be
considered shallow subsurface soils; however, for purposes of this
discussion soils from 0 to 3 feet will be referred to as surface
soils. Surface soils were collected employing hand, augering
techniques as previously described. Figure 4 is an isocon
displaying the relative distribution of total pesticides in surface
soils at the Fairfax site.
In addition to surface soil samples, ten soil borings were
completed utilizing hollow stem auger techniques. Soil samples
were collected for analysis from the surface, and from just below
the interface of the vadose and saturated zones. Analytical
results from some deep soil boring samples have indicated elevated
levels of chlorinated pesticides.
5.2.1.1 VOCs in Soils
Soil samples collected throughout the RI have identified relatively
low levels of various volatile organic chemicals (VOCs). The most
commonly detected were acetone and methylene chloride; however, the
data validation review suggests that these and some other
contaminants may be laboratory artifacts. Two other chlorinated
solvents were identified in soil samples, tetrachloroethylene
(PCE), and trichloroethylene (TCE), although the TCE detected in
two samples is believed to be a laboratory artifact. In addition,
the aromatic solvents, benzene, toluene, ethylbenzene, and xylene
were identified. Xylene is considered to be directly related to
the formulation process. The VOCs found during the RI are
discussed below.
Acetone
Acetone is a clear, colorless liquid with a fragrant mint-like
odor. Acetone is a common organic solvent which is highly soluble
in water. It is also one of the most common laboratory
contaminants found in environmental samples. Acetone was
-------
HOJIGZI
TDTAL PESTICIDES
0-1'
ITKM
OMtML
Dntmrrnxr
IOCIDUM WILL UK.
»* - roncuc *-(•
<«*>
FIGURE 4J
PESTTCIK3 IN SOILS
HELENA OCMICAL COMPANY
FAWAX SOUTH CAROLINA
PWQ M*ugr Hn H
(0
rH
C-H
•H O
CO
cn
Q> i-H
M1 T3 (d
-H -H
0) O U
Vl -H -H
3 OJ >W
Cn w V^
fc,
0)
CO
-------
22
identified in approximately 57 percent of the soil samples
collected. Concentrations range from 2 Hg/kg (ppb) - 13,000 ^g/kg
(ppb).
Methylene Chloride
Methylene chloride is a clear, colorless, highly volatile liquid.
It is used as a degreaser, photographic film processing chemical,
solvent, raw material for organic synthesis, and a fumigant. It is
soluble in water to 20,000 mg/1. Methylene chloride is a common
laboratory contaminant found in environmental samples.
Approximately 38 percent of the surface soil samples analyzed
indicated variable levels of methylene chloride. Concentrations
range from 2 ppb - 140 ppb.
Tetrachloroethylene
Tetrachloroethylene (PCE) is a colorless liquid with a chloroform-
like odor, and is slightly soluble in water (150 mg/1) . It. is used
for dry cleaning, metals degreasing and heat exchange fluid. PCE
was formerly used in mixtures with grain protectants and certain
liquid grain fumigants (vermifuge).
Tetrachloroethylene was identified in less than one percent of the
soil samples. Concentrations ranged from 11 ppb - 240 ppb.
Trichloroethylene
Trichloroethylene (TCE) is a colorless, mobile, volatile liquid
with a chloroform-like odor. It is used as a degreaser, dry
cleaning solvent, gas purification agent, and a raw material in
organic chemical manufacturing.
Trichloroethylene was identified in two soil samples, SS-10-1 and
SS-19-2. The concentrations were 24 and 210 ppb, respectively. TCE
was also detected at 19 ppb in the trip blank submitted with these
samples on 02/26/91. The samples were run consecutively indicating
the values may be laboratory artifacts or lab error.
Benzene
Benzene is a clear, colorless, volatile liquid which' is very
slightly water soluble. Benzene is a component of gasoline and an
organic solvent which was formerly used (on a limited basis) in
pesticide formulation.
Benzene was identified in approximately three percent of the
samples. Concentrations ranged from 3 to 1,300 ppb.
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23
Toluene
Teluene is a colorless liquid with a benzol-like odor. It is used
as a solvent, and in dye manufacturing, artificial leather
production, asphalt and naphtha constituents, fuel blending and
extraction of organic soluble plant materials.
Approximately eight percent of the soil samples identified low
levels of Toluene. Samples range from a low of 1 ppb to a high of
210 ppb.
EthyIbenzene
Ethylbenzene is a colorless liquid with an aromatic odor and
limited water solubility (140 mg/1) . It is used in synthetic
rubber manufacturing, as a solvent, and is component of gasoline.
Ethylbenzene was detected in approximately three percent of the
soil samples. Concentrations range from 3 ppb - 4100 ppb.
Xylene
Xylene is a clear liquid which consists of a mixture of three (3)
isomers: ortho-, meta-, and para-. Xylene is used in the
manufacture of a number of consumer products, and is also a
component of gasoline and a raw material for synthesis of organic
chemicals.
Xylene was detected in four percent of the soil samples. The
highest concentrations were found in the soils beneath the cap of
the former landfill. The values range from 3 H-g/kg to 27,000
Hg/kg.
5.2.1.2. Semi-Volatiles in Soils
Although no semi-volatile compounds were confirmed in soils during
the Data Validation report three tentatively identified compounds
(TIC's) were recognized: disulfoton, chlorobenzilate, and
butylphosphorotrithioate. Levels of disulfoton ranged from 60 ppb
- 430,000 ppb and were identified in four percent of the soil
samples collected. Butylphosphorotrithioate was detected in three
samples at a concentrations ranging from 750 to 7900 ppb.
Chlorobenzilate was not detected in samples collected by ENSAFE,
but was identified in one split sample collected by the EPA
oversight contractor. Disulfotone sulfone was identified in one
sample at 51 ppb. Disulfoton sulfone is a degradation product of
disulfoton.
Disulfoton (a.k.a. Di-syston) is a colorless, oily liquid (in the
pure state), and the technical grade is brown in color. It is
generally insoluble in most organic solvents. Disulfoton was
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24
produced as an insecticide for mites and aphids on small grains,
corn, sorghum, cotton, and other field crops.
Butylphosphorotrithioate is a colorless to pale yellow clear liquid
which is insoluble in water. It was produced as a pesticide and
cotton defoliant.
Chlorobenzilate (a.k.a. 4,4'-Dichlorobenzilic acid ethyl ester) is
a viscous liquid sometimes yellow in color, and is slightly water
soluble. It was manufactured as an acaricide. It was approved for
use in the USA in 1969 for application on 11 crops which were
primarily fruits and vegetables.
5.2.1.3 Pesticides in Soil
Soil samples collected during the RI have indicated a varied
distribution of individual pesticide components. Concentrations
for total pesticides range from below detection limits to 7170
mg/kg in surface and shallow subsurface soils. For the purpose of
total pesticides, the values indicated represent the summation of
all pesticide components identified during the RI. The primary
pesticide constituents identified were DDT (and its degradation
products), toxaphene, and BHC (including isomers). Contaminant
distribution data have been generated for the primary constituents
identified on the property. Those components comprising a less
significant fraction of the total pesticides identified include
aldrin, chlordane (including isomers), dieldrin, endrin, endrin
ketone, total endosulfans, heptachlor, heptachlor epoxide, and
methoxychlor.
The most significant levels of pesticides identified on the site
were found immediately north, northwest, and/or east of the north
warehouse. The overall levels of contamination generally show a
decrease in concentration with depth from the surface to three feet
below grade. Isolated "hot spots" however, show an increase in
concentrations at the one to two foot interval with subsequent
decrease in concentration again with depth. Individual pesticides
are further detailed below.
Toxaphene
Toxaphene (a.k.a. chlorinated camphene) is produced as a yellow,
waxy solid with a pleasant piney odor. Toxaphene is nearly
insoluble in water.- It was used as an insecticide for cotton,
early stages of vegetables (peas, soybeans, and peanuts), and wheat
and other small grains. Current uses are limited to cattle and
sheep dipping (under certain provisions), disinfecting buildings,
and termite, insect, rodent and other pest control (limited
application). Toxaphene has not been produced commercially in the
U.S. since 1982.
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25
Toxaphene is generally present at the highest concentration in the
pesticide fractions identified at the Site. Toxaphene was
identified in 40 percent of the samples collected and
concentrations ranged in value from 42 ng/kg (ppb) to 2700 mg/kg
(ppm) . Toxaphene data from the RI indicate contamination with the
highest concentrations is found immediately northwest of the north
warehouse, and elevated concentrations were also identified east of
the building.
DDT, DDE, and DDD
DDT (a.k.a. 4,4'-Dichlorodiphenyltrichloroethane) was produced as
colorless crystals or white/off-white powder. It is odorless or
has a slight aromatic odor. DDE and DDD are found as contaminants
(minor fraction) in DDT, and may also be produced through
degradation of DDT. These compounds are non-systemic contact and
stomach insecticides. DDT was used primarily to control insects
capable of spreading malaria, typhus, and other insect transmitted
diseases. Use of these products has been banned in the U.S.
DDT was detected in approximately 61 percent of the soil samples
collected during the RI. The reported concentration of DDT and its
degradation products in soils ranged from 2.3 ppb to 2,800 ppm.
Contaminant distribution data generated during the RI indicate
contamination from DDT is greatest at the surface and decreases
with depth.
BHC (Lindane) and laomers
Lindane is produced as a white crystalline powder, and is only
slightly soluble in water (varies between isomers). Lindane is a
organochlorine pesticide. Lindane is the gamma isomer of benzene
hexachloride (BHC).
All four BHC isomers (alpha, beta, gamma, and delta) were
identified in soil samples collected during the investigation. The
most frequently detected isomer was beta-BHC which was found in
approximately 38 percent of the soil samples. Concentrations of BHC
range from 0.1 ppb - 390 ppm. Again, data indicate a decrease in
concentration levels with increased depth.
Aldrin
Aldrin is produced as tan to dark brown crystals which are
essentially insoluble in water. It was formerly used as an
insecticide, and has been registered as a termaticide in the USA.
The manufacture and use of aldrin have been banned in the USA.
Aldrin was detected in approximately 17 percent of the soil
samples. Values ranged from 1.2 ppb - 800,000 ppb. Predominant
soil contamination from aldrin was identified west and northwest of
the north warehouse.
-------
26
Chlordane
Chlordane (pure form) exists as a colorless to amber, odorless,
viscous liquid which is insoluble in water. Chlordane was also
produced in emulsifiable concentrates, granules, dusts and wettable
powders (for termite control) . It was formerly used as a fumigant
and acaricide, and also as a home and garden pesticide/insecticide.
As of 1983, the only approved use of chlordane in the USA is for
termite control.
Chlordane (alpha and gamma isomers) was identified in approximately
four percent of the soil samples. Chlordane concentrations range
from 15 ppb - 58,694 ppb.
Dieldrin
Dieldrin was produced as white crystals or light tan flakes which
are odorless and insoluble in water. Dieldrin was formerly used to
control soil insects, insects of public health concern and
termites. Its use as a broad spectrum insecticide ceased in 1974
when EPA restricted its use to direct soil injection for termite
control and non-food seed/plant treatment.
Dieldrin was identified in approximately 36 percent of the soil
samples collected during the RI. Dieldrin concentrations range
from 4.6 ppb - 96,000 ppb. Soil contamination was identified
between the warehouse and the former house and in the low lying
areas north and west of the former landfill. Concentrations
decrease with depth.
Total Endosulfans
Endosulfan (two (2) isomers) was produced as brown crystals
essentially insoluble in water. Its primary application was as an
insecticide for vegetables. Endosulfan sulfate is a degradation
product of endosulfan.
Endosulfan was detected in approximately 5 percent of the soil
samples collected. Endosulfan sulfate was detected in approximately
13 percent of the samples analyzed. Concentrations ranged from 2.1
ppb - 22,000 ppb. The most significant concentrations were
identified immediately northwest of the warehouse. Less
significant contamination was identified in the low lying area
northwest of the landfill. Analytical data indicates that
Endosulfan concentrations have decreased with depth.
Endrin
Endrin was produced as water insoluble white crystals dissolved in
a liquid carrier (organic solvent). The only uses currently
registered in the US are for cotton and bird perches. It is a
persistent insecticide used on field crops to control army cutworm,
-------
27
meadow voles, and grasshoppers under strict adherence to Federal
regulations on application. Endrin ketone is an impurity in and
degradation product of endrin.
Endrin and Endrin Ketone were identified in soil samples west of
the warehouse and west-northwest of the landfill. Concentrations
ranged from 0.74 ppb - 9,200 ppb. Approximately 12 percent of the
samples collected contained endrin and 16 percent its degradation
product endrin ketone. Concentrations appear to decrease with
depth with the exception of one anomaly from sample SS-3-3.
Keptachlor
Heptachlor was produced as white to tan, waxy-looking solid
crystals which are nearly insoluble in water. It has been used as
an insecticide for termite control, and was also formerly used in
fieldcrops (including corn, citrus, pineapples, cereal, vegetables
sugar beets, nuts and cotton) for pest control (fire ants, boll
weevils). Heptachlor epoxide is a degradation product of
heptachlor.
Heptachlor was identified in approximately 25 percent of the soil
samples. The concentration of heptachlor and its degradation
products ranged from 1.0 ppb to 68,000 ppb. The predominant area
of. contamination was in the low lying area north and west of the
landfill with some minor levels of contaminant identified, north of
the warehouse.
Meth.oxych.lor
Methoxychlor was produced as a white, crystalline solid- dissolved
in an organic liquid carrier. It is essentially insoluble in
water. Methoxychlor has been used as an insecticide for livestock
and poultry, alfalfa, citrus, vegetables, soybeans, deciduous
fruits and nuts, and other crops as well as home use, garden and
ornamental plants, and forests. A common formulation is
Methoxychlor with.Diazinon (1:2 mix).
Four percent of the soil samples collected contained methoxychlor.
Concentrations ranged from 24 ppb - 12,000 ppb. Methoxychlor was
identified in the low lying area north of the landfill and
northwest of the warehouse.
5.2.2 Ground Water
A total of 22 monitoring wells were installed at the Fairfax site
during the RI. Thirteen wells were completed as shallow monitoring
wells and nine wells were completed as deep monitoring wells. All
wells were completed within the upper Eocene aquifer system. The
installation and subsequent sampling of wells during Phase III of
-------
28
the RI corresponded with the third quarter sampling event of 1991
for the wells installed during Phase II-A.
Chlorinated pesticides and volatile organics were identified in
samples collected from on-site shallow monitoring wells. One deep
well (MW-3) also indicated low levels of pesticides in ground
water. Endosulfan sulfate was detected in MW-5; however, the
quantity was "j" flagged. Four metals were detected in various
wells at concentrations above their respective MCLs and are
discussed below.
The City of Fairfax municipal well (south well) was sampled during
Phases II-A and III of the field investigation. Samples were
collected both before and after treatment by a chlorination
process. No Site-related contaminants were identified in any of the
samples collected from the municipal well samples. The north well
field, which is located approximately one mile north of the Site,
was not sampled.
5.2.2.1 Volatile Organics in Groundwater
Groundwater samples collected throughout the RI have identified low
levels of various fractions of the volatile compound list. The
most commonly detected were acetone and carbon disulfide; however,
data validation suggests that these and other minor constituents
are laboratory artifacts. Other constituents identified include
benzene, chlorobenzene, chloroform, 1,2-dichloropropane,
ethylbenzene, methylene chloride, and xylene were identified.
Acetone
Acetone was identified in groundwater samples from all site
monitoring wells except for MW-1, MW-10, 20, 21, 22, 23, and 24.
Additionally, acetone was identified in the raw (before
chlorination) and finished (after chlorination) water samples
collected from the Fairfax municipal well. As mentioned previously
acetone is considered to be a lab artifact. Concentrations range
•from 3 ^ig/1 (ppb) - 150 p.g/1 (ppb) identified in numerous
groundwater samples.
Carbon Disulfide
Groundwater samples from all site monitoring wells except for MW-1
and MW-3 identified varying levels of carbon disulfide. The
untreated city water was also positive for carbon disulfide.
Concentrations range from 3 ppb - 130 ppb. Carbon disulfide was
only detected in eight samples collected during all sampling events
subsequent to Phase II-A. Many of the reported concentrations were
"j" flagged (estimated values). In addition to the Phase II-A
wells, carbon disulfide was identified in monitoring wells MW-18,
MW-20 and MW-22 installed during Phase III of the RI.
-------
29
Methylene Chloride
Methylene chloride was detected in groundwater samples collected
from monitoring wells MW-1, MW-2, MW-4, MW-5, MW-8, MW-10, MW-12,
MW-14, MW-19 and the finished city water during the investigation.
Concentrations range from 1 ppb - 7 ppb. Once again, many of the
reported concentrations were "j" flagged.
Benzene
Benzene was identified in groundwater samples collected from MW-12
during Phase II-A, the first quarterly sampling event under Phase
II-B, and the December sampling event. Concentrations of benzene
varied from 34 ppb to 52 ppb in the three respective sampling
events. Benzene was detected in MW-4 during two sampling events at
concentrations of 5 and 6 ppb. During Phase III benzene was
detected in MW-14 at 37 ppb.
Chlorobenzene
Chlorobenzene was detected in groundwater samples collected from
monitoring wells MW-4, MW-6, MW-8, MW-12 and MW-14. Concentrations
ranged from 2 ppb - 17 ppb.
Chloroform
The finished water sample collected from the City of Fairfax
municipal water well detected chloroform at 2 ppb. This occurrence
probably results from the City's water chlorination process. No
Chloroform was detected in the municipal well system during Phase
III sampling.
1,2-Dichloropropane
1,2-Dichloropropane was detected in samples collected from
monitoring wells MW-8, MW-12, and MW-14 in the quarterly sampling
events. Concentrations range from 6 ppb to 28 ppb.
Ethylbenzene
Ethylbenzene was detected in samples collected from monitoring
wells MW-4, MW-8, MW-12, MW-14, MW-19, MW-22, and MW-24 during
sampling events completed to date. Concentrations range from 2 ppb
- 190 ppb.
Xylene
Groundwater samples collected from monitoring wells MW-4, MW-6, MW-
8, MW-12, MW-14, MW-19, MW-22 and MW-24 exhibited elevated levels
of xylenes. Concentrations ranged from 5 ppb - 2000 ppb.
Monitoring well MW-4 contained the highest concentration.
-------
30
5.2.2.2 Semi-Volatlies in Ground Water
Disulfoton was identified in monitoring wells MW-4 and MW-12 during
two of the groundwater sampling events. Concentrations of 78 ppb
and 110 ppb were reported in MW-4 while concentrations of 3 ppb and
4 ppb were reported for MW-12. Both of the concentration values for
MW-12 were reported as estimated concentrations (i.e., *j"
flagged). Butyl phosphorotrithioate was identified in MW-15 during
Phase III at a concentration of 49 ppb, and was likewise "j"
flagged.
5.2.2.3 Pesticides in Groundwater
Monitoring well samples indicate that elevated levels of pesticides
exist in shallow groundwater. Contaminants identified .appear to
consist primarily of toxaphene, DDT (and its degradation products) ,
BHC (including isomers) and dieldrin. Those components comprising
a less significant fraction of the total pesticides identified
include aldrin, chlordane (including isomers), endrin and endrin
ketone, total endosulfans, and heptachlor and heptachlor epoxide.
Methoxychlor, which was identified in soil samples, was not
identified in groundwater.
Toxaphene
Toxaphene contamination comprises the most significant
concentrations of the pesticides fraction identified in groundwater
at the Site. Toxaphene was identified in groundwater samples from
monitoring wells MW-4, MW-6, MW-8, and MW-10 collected during the
Remedial Investigation. Concentrations ranged in value from 9.9 ppb
- 120.0 ppb. The laboratory did not identify toxaphene in
groundwater samples collected during the March 1991 sampling event;
however, toxaphene is believed to be present in MW-4, MW-6, and MW-
10. Internal validation and assessment of chromatagrams indicates
the probable presence of toxaphene in these wells-.' Due to severe
matrix interferences in these samples, however, toxaphene
quantification was not possible. The maximum concentration of
toxaphene was detected in MW-8.
The Maximum Contaminant Level (MCL) for toxaphene in groundwater
were established at 3.0 ppb.
DDT, DDE, and DDD
DDT, DDE, and DDD were detected in groundwater samples collected
from monitoring wells MW-4, MW-6, MW-12, MW-14, and MW-22 during
the RI and ranged in value from 0.045 ppb to 2 ppb. An MCL has not
been established for DDT, or its metabolites DDE and DDD.
-------
31
BHC (Lindane)
Lindane and its BHC isomers (alpha, beta, and delta) were
identified in groundwater samples collected from monitoring wells
MW-3, MW-4, MW-6, MW-8, MW-10, MW-12, MW-14, MW-16, MW-18, MW-22,
and MW-24. Concentrations of BHC range from 0.024 ppb - 42.0 ppb.
The MCL for lindane has been established at 0.2 ppb.
Dieldrin
Dieldrin was identified in groundwater samples from monitoring
wells MW-4, MW-6, MW-8, MW-10, MW-12, and MW-14 in the first
quarterly sampling event. Subsequent quarterly sampling events
identified dieldrin in monitoring wells MW-6, MW-8, MW-10, MW-12,
MW-14, MW-16, MW-18, MW-22, and MW-24. Concentrations range from
0.024 ppb .-5.5 ppb.
An MCL has not been established for dieldrin.
Aldrin
Aldrin was detected in groundwater samples collected from
monitoring wells MW-4, MW-6, MW-8, and MW-12. Values ranged from
0.22 ppb - 7.9 ppb. The maximum concentration was detected in MW-
4.
An MCL has not been established for aldrin.
Chlordane
Chlordane (alpha and gamma isomers) was identified in groundwater
samples collected from monitoring wells MW-4 and MW-12. Chlordane
was detected in MW-4 during the Phase II-A sampling events at 1.2
ppb. Chlordane was identified in MW-12 during Phase II-A, and both
Phase II-B sampling events at concentrations ranging from 0.31 ppb
- 1.3 ppb. The MCL established for Chlordane is 2.0 ppb.
Total EndoBulfans
Endosulfans were detected in monitoring wells MW-4 and MW-6 during
the Phase II-A at concentrations of 1.8 ppb and .021 ppb
respectively. Phase III groundwater sampling indicated elevated
concentrations of endosulfans from monitoring wells MW-2, MW-5, MW-
14, and MW-24. Concentrations ranged from 0.054 ppb to 0.62 ppb.
Endrin
Endrin and endrin ketone were identified in groundwater samples
collected from monitoring wells MW-4, MW-6, MW-8, MW-10, MW-12, MW-
18, MW-22, and MW-24. Concentrations ranged from 0.3 ppb - 2.1 ppb
for endrin, and from 0.064 ppb - 18 ppb for endrin ketone. The MCL
for endrin is 2.0 ppb.
-------
32
Heptachlor
Heptachlor and heptachlor epoxide were identified in monitoring
wells MW-6 and MW-12. The concentrations identified were 0.12 ppb
for heptachlor and 0.57 ppb for heptachlor epoxide. Groundwater
samples collected during Phase III of the RI did not show
detectable quantities of heptachlor or heptachlor epoxide.
MCLs have been established at 0.4 ppb and 0.2 ppb, respectively.
5.2.2.4 Metals in Groundwater
The metals analyses conducted during the Phase II-A sampling event
did not provide conclusive evidence that metals contamination of
ground waters was a result of releases from the Site. Most metals
in groundwater were detected at concentrations below detection
limits or at levels comparable to background concentrations.
During subsequent Phase II-B and Phase III groundwater sampling
events beryllium, chromium, cadmium, and lead were detected in
samples at levels which exceeded their respective MCLs.
Beryllium
Beryllium was identified in monitoring wells MW-4, MW-8, and MW-20
at concentrations of 6 ppb, 9 ppb, and 5 ppb respectively. The MCL
for beryllium is 4 ppb. The detection of beryllium at
concentrations above MCLs was a one time occurrence in each of the
wells; therefore its presence does not appear to be significant.
Chromium
The presence of chromium was detected in monitoring wells MW-4, MW-
6, MW-20, MW-23, and MW-24 at levels which exceeded the MCL of 100
ppb. The maximum concentration reported was 415 ppb which was
detected in MW-20.
Cadmium
Cadmium was identified in MW-20 during both the September/October
1991 and December 1991 sampling at a concentration of 10 ppb. The
MCL for cadmium is 5 ppb.
Lead
Lead was detected above the action level of 15 ppb in samples
collected from monitoring wells MW-12, MW-20, MW-23, and MW-26.
Lead was most frequently identified above the action level in MW-
12.
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33
Table 5
T.W. 4-22
Peiticidet (SurUc* W«ter/Sedimcm
Prw«« U-A/Tl-B. Ill ;
PARAMETER
alpha - BHC
beta - BHC
gamma • BHC
delta • BHC
Aldrin
Dioldfin
4.4' ODD
4,4' DOT
4.4- DOE
.
Endrin Ketona
Heptachlor
Toxaphena
Gamma '
Chlordine
Alpha
Chlordano
Endrin
MATRIX
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment •'--
Surface Watar
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
Surface Water
Sediment
NUMBER OF
SAMPLES
2 .
10
2
to
2
10
2
10
2
1C
2
10
2
to
2
10
2
10
2
10
2
10
2
10
.2
10
2
10
2
10
'NUMBER OF
HfTS
0
2
2
3
0
2
1
0
0
1
2
1
2
9
1
7
0
8
2
0
0
2
1
2
0
2
0
1
0
1
RANGEIppbl
: —
0.1-60
0.57-1.2
0.1-500
—
0.1-67
—
—
—
—
0. 45-6.2
—
0.045-0.23
18-3400
—
S.7'5700
—
9.8-280
0.35-1.4
—
—
2.1-25
78-42000
18-300.7
—
—
-
MEAN(ppb)
—
30.5
1
171.7
—
33.6
0.28
—
—
990
3.5
3200
0.2
437
1.2__
862.9
—
80
1
—
—
13.6
NOT
QUANTIFIED
21039
459.4
443
—
1.6
-------
34
5.2.3 Surface Water and Sediments
Sediments in the wetland areas located in the northern portion of
the Site were found to be contaminated with semivolatile chemicals
and pesticides. Table 5 summarizes the findings of the RI with
respect to contaminated sediments. There are no chemical-specific
ARARs for sediments, but the levels of contamination found in the
RI exceed concentrations that have been shown through toxicological
research to have an adverse impact to aquatic life due to toxic
effects of these contaminants. This research is summarized in the
National Oceanographic and Atmospheric Administration (NOAA)
publication .entitled The Potential for Biological Effects of
Sediment-Sorbed Contaminants Tested in the National Status and
Trends Program, NOAA Technical Memorandum NOS OMA 52, August, 1991.
The pattern and distribution of contamination in the sediments
indicate that the primary source of contamination is the landfill
that was placed partially in the jurisdictional wetlands. Sediment
contamination also extends into off-site drainage pathways for
surface waters. The sediment contamination found in both on-site
and off-site locations poses an unacceptable risk to environmental
receptors.
On-site surface waters were found to have been contaminated with
pesticides at levels which exceed Ambient Water Quality Criteria
(AWQC) for the protection of aquatic life. Federal AWQC have been
established under the authority of Section 303 of the Clean Water
Act for the purpose of establishing protective guidelines for
ambient water quality. AWQC as developed by EPA are identified in
Section 121 of CERCLA as amended by SARA as chemical-specific ARARs
for NPL sites. In addition, the AWQC have been adopted by the
State of South Carolina as ambient surface water quality standards,
and are therefore ARARs for the Site. Table 5 also summarizes the
findings of the RI with respect to surface water contamination at
the Helena Chemical Site. The surface water contamination
identified as part of the RI also poses an unacceptable risk to
environmental receptors in the on-site wetland areas and in
drainage pathways leading off-site.
6.0 SUMMARY OF SITE RISKS
A Baseline Risk Assessment was conducted to evaluate the risks
presented by the Helena Chemical Superfund Site to human health and
the environment, under present day conditions and under assumed
future use conditions. Currently, there are no residents living on
the Site and only a few residents residing close to the Site.
There are no potable water supply wells on the Site, although there
is a municipal water supply well located less than one-quarter mile
away. Information gathered from census data regarding population
trends in Allendale County and surrounding areas suggests that
future land use will remain commercial and industrial, with little
potential for residential use of groundwater as a potable water
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35
source. The Site was evaluated, however, under residential
exposure scenarios, including exposure pathways involving the use
of shallow ground water as a potable water supply source. These
exposure scenarios correspond to potential future use of the Site
for residential development.
Under the current land use scenario, potential human receptors at
the Site include residents in the vicinity of the Site who may be
occasional Site trespassers, and workers on the Site. The Site is
surrounded by residential, agricultural and light industrial areas.
Beyond these areas immediately surrounding the Site (including the
City of Fairfax) , the local area is not densely populated, and
consists primarily of agricultural land and forests. The most
likely potential human receptors under the current land use
scenario are workers and occasional trespassers. No private
drinking water wells were identified either on-Site or immediately
downgradeent from the Site, and no users of surface water for
potable water supplies were identified downgradient from the Site.
Under current land use, the Reasonable Maximum Exposure (RME) is
represented by the individual worker or Site trespasser who may be
exposed by direct contact and incidental ingestion of surface soil
and stream sediments.
Potential environmental receptors under the current land use
scenario include the plants and animals at the Site. Site
features, including the small unnamed stream and wetlands adjacent
to the Site, and nearby wooded areas and open fields, provide a
variety of habitats. No unique or critical habitats have been
identified at the Site, and no vegetative stress is evident based
upon site visits by regulatory personnel. No threatened or
endangered species have been observed at the Site or in adjacent
areas.
Future land use for the Site was considered to include potential
development of the area as residential property. This potential
land use scenario is considered to be that which would result in
the greatest degree of risk to human health should the Site remain
unremediated. The RME under a residential land use scenario is
assumed to be an adult person or child living on the Site property
and drinking potable water obtained from a private well drilled
into the Barnwell Formation. Under the future land use scenario,
environmental receptors would likely be more limited than at
present, since residential development of the property would in all
likelihood involve the elimination of the wetland and forested
areas on and adjacent to the Site.
EPA has determined that the elevated levels of pesticides in the
soils and ground waters at the Site pose the primary hazard to
human health at the Site. In addition, the elevated levels of
pesticides in the sediments and soils located in the wetland areas
adjacent to and downstream of the Site pose a hazard to
environmental receptors inhabiting those areas. Primary exposure
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36
pathways for humans are incidental dermal contact with and
ingestion of contaminated soils, and ingestion of contaminated
ground water. Air transport of particulate matter contaminated
with Site-related constituents of concern is not considered to be
a significant risk to human health because the contaminated soils
are generally in vegetated areas and the most heavily contaminated
soils have been removed prior to this time. Air sampling results
conducted during the Remedial Investigation indicated that airborne
contamination was not present above levels that would pose a
significant risk to human health.
EPA has established in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP), 40 CFR Part 300, a range of 1 X
10"4 to 1 X 10"6 as acceptable limits for excess lifetime
carcinogenic risks. Excess risk within EPA's acceptable limits
means that any individuals exposed to Site conditions under the
assumed exposure scenarios will run a one in ten thousand (1 X 10"*)
to a one in one million (1 X 10~6) increased chance of developing
cancer. Under the "No Action" scenario, (assuming the Helena
Chemical Site is left as it is now) the estimated carcinogenic risk
for current land use is 8.0 X 10"5. The estimated excess cancer
risk calculated for the future land use scenarios at the Site is
2.6 X 10"*. These calculated risks for the future land use scenario
exceed the acceptable risk levels established by EPA and are based
on the assumption that no cleanup activities will have occurred.
EPA has also established acceptable exposure limits based upon non-
carcinogenic health effects. A Hazard Index (HI) of 1.0 or greater
has been established by EPA as the criterion defining unacceptable
levels of exposure for non-carcinogenic health effects. The HI is
the ratio of exposure levels resulting from site conditions to
acceptable exposure levels (ie., exposure levels that result in no
adverse health affects) for any given contaminant. The HI for
potential non-carcinogenic effects under the current land use
exposure scenario is 0.3. The associated Hazard Index for
non-carcinogenic effects under the future land use exposure
scenario is 8.6.
Actual or threatened releases of hazardous substances from this
Site, if not addressed by the preferred alternative or one of the
other active measures considered, may present a current or
potential future threat to the public health, welfare, or the
environment.
6.1 CONTAMINANTS OF CONCERN
Numerous chemical contaminants were identified in site media during
RI Phases II-A, II-B, and III. Tables 6, 7, 8, 9, and 10 provide
a summary of those contaminants which were evaluated or considered
for evaluation during the Baseline Risk Assessment process. In
Tables 6-10 the term "hit" or "hits" refers to positive results of
-------
Table 6
37
TO&njtf : ;•:'.:.
Summary of SoiPe«t>cki« Concentration*
HCFSCShe :•;
Parameter
Aldrin
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
4,4'-DDT
4,4'-DOE
4,4'-DDD
Oieldrin
Endoeulfan II
Endosulfan
Sulfate
Endrin
Endrin Ketona
SolCUaa
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Number: of.
Sample*;
261
162
261
152
261
152
261
152
261
152
261
152
261
152
261
152
261
152
261
152
261
152
261
152
261
152
Number of Hit*
35
6
32
6
52
15
22
4
19
4
124
41
66
31
72
22
79
21
13
4
33
16
26
11
35
12
• ' .
.. Range
(Ppb)
1 .2 - 800000
1.4-810O
2.1 - 390000
4.4- 1800
4.9 - 270000
4.9 - 6200
4.1 -210000
5- 1500
4.2 - 220000
5-67
5.1 - 2800000
8.5 - 220000
0.74- 21000
4.5- 15000
2.3 - 750000
4.0 - 600OO
3.7 - 960OO
4.6-44OOO
23 - 7100
23-7100
2.1 - 22000
2.6 - 22000
5.8- 1600
9.1 - 1600
2.1 - 9200
5.3 - 1200
Mean (ppbj
27100
1690
12300
530
9900
750
19000
380
11700
34
31000
19200
1100
910
16800
6 400
3500
2700
660
1820
1040
1920
390
650
530
220
-------
Table 6 (continued)
38
TabU
Summary of Sol Pee
HCFSI
Parameter
Heptachlor
Heptachlor
Epoxida
Methoxychlor
Toxaphene
alpha-Chlordana
gamma-
Chlordane
Sol CUM
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Number of
Sample*
261
152
261
152
261
152
261
152
261
152
261
152
7-1
:Sha
Number of Htt»
11
3
9
4
10
6
62
22
4
1
6
4
Range
(ppbl
6.1 - 68000
19-35
2.4 - 29
6-29
24- 12000
24- 12000
78 • 2700000
78 - 350000
15-9600
—
16- 14000
16-66
Mean (ppb)
9300
26
15
20
2050
3300
66000
43300
2500
15
2600
39
-------
39
Table 7
Table 7-2
Summary of Soil Semivolatile Concentrations
HCFSC Site
Parameter || Soil Class
Disulfoton0
Tributylphoshoro-
trithioate"
Chlorobenzilate"
Total
Surface
Total
Surface
Total
Surface
Number
of
Samples
261
152
261
152
261
152
Number of
Hits
12
1
3
0
0
0
Range ~
60-
430000
—
750-
7900
—
—
—
Mean
(ppb)
59400
97
3200
—
—
—
Notes: Only disulfoton of the semivolatile SAS compounds (originally Tentatively Identified
Compounds) were detected in site surface soils.
a One disulfoton sulfone hit (51 ppb) was identified during Phase II-A. This hit occurred as a
Tentatively Identified Compound with estimated ("J" flag) concentration. This hit was not
used to compute the average disulfoton concentration.
Compound identified in a limited area in immediate vicinity of landfill.
-------
Table 8
40
Table 7-3
Summary of Sol VolatB** Concentration*
HCFSCSH* ••:•'• :'y-.-- •- • . Y".;:;-'. : ^ • Y':r:: ;v': :vl
Parameter
Benzene
Chloroform
Ethylbenzera
Methylene Chloride
Toluene
Acetone
2-Butanone
Xylenes
Carbon Disulfide
Trichtoroethytene
Styrene
1 ,2-Oichloroethene
Tetrachloroethene
1 ,2-Oichloropropana
Chlorobenzene
Sof«le*»
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Total
Surface
Number of Sample**
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
210
151
Numb«rofHttr
6
0
5
2
7
0
80
39
17
4
119
69
31
13
9
1
4
3
2
0
2
O
2
1
2
2
2
0
4
0
Rang*
3- 1300
—
1-11
2-11
3-410O
— '
2- 140
2 - 140
1 - 120
1 -89
2- 13000
2- 13000
1 -36
3 -32
3 - 27000
—
12-48
19-48
24-210
__
—
—
2- 12
—
1 1 - 240
1 1 - 240
15-75
_
5 -9000
—
MeaMppbl
223
—
4
7
1260
—
20
30
32
35
320
600
12
13
4250
3
30
35
117
—
2
—
7
12
130
130
45
—
2300
—
-------
Table 9
41
Ta«a7-4 ' '.:':-- ;• • •• ;:;/.
Summary of Groundwater Contaminants .: . ...••,.- .\x/.
HCfscstu • ---'pf:1'-' '-* -f--0.:-:*€:
Parameter,:
Aldrin
alpha-BHC
beta-BHC
dulta-BHC
gamma-BHC
4,4'-DDT
4,4'-DDD
4,4'-DDE
Oieldrin
Endosulfen II
Toxaphene*
Endrin
Endrin Ketona
CRQL
0.05
0.05
0.05
0.05
0.05
0.1
0.1
0.1
0.1
0.1
1.0
0.1
0.1
Sampling Data
October 91
December 9 1
October 91
December 91
October 91
December 91
October 91
December 91
October 91
December 91
October 9 1
December 91
October 9 1
December 91
October 9 1
December 91
October 91
December 91
October 91
December 91
October 91
December 91
October 91
December 9 1
October 91
December 9 1
Number
oJHrU
2
2
9
8
8
7
7
5
7
6
1
1
3
1
2
0
9
7
1
0
0
1
0
1
7
6
Rang* (ppb)
at Hit*
0.88 - 2.3
0.66-1.2
O,1 T - 18
0.17-31
0.26-26
0/19 -26
O.O24 - 5.7
O.O94*1.2
0,1 Z- 6.6
O.23 - 2.2
«_.
—
O.O45-0.66
_
O.O51 - 2.0
. <_-.
O.O24-3.4
Q.23 - 6.5
—
_
_
_
__
—
0.064-18
O.17-11
Mean
(ppb»
otHrtt
1.59
0.93
2.78
6.72
5.42
4.70
1.25
0.62
1.47
0.91
0.45
1.2
0.26
2.10
1.03
_
0.99
2.70
0.62
__
—
36.O
0.3
6.15
4.15
' •'•
35%Upp«r:;:
Confidence
UmftMaan 1
IppW :
0.266
3.44
3.74
1.06
0.69
0.175
0.24
0.21
1.11
0.13
8.29
0.081
2.98
-------
Table 9 (continued)
42
Table 7-* " . \ •".'' '"' f'
Summary of -Groundwatar Contaminants
HCFSCSh.
Parameter
Endosulfan Sulfata
Benzene
Disulfoton
TBPT
Chromium
Lead
CRQL
0.1
5.0
5
10
Sampling Oat*
October 91
December 9 1
October 91
December 91
October 91
December 9 1
October 91
December 91
October 91
December 91
October 91
December 91
Number
ofHfta
3
0
2
1
0
2
0
1
21
14
24
16
Range (ppb)
of Hits
0,064-0,12
—
6-37
—
—
3- 11O
__
—
3.3 -416
tO.O • 298
0.7 -4A
1.0-38.2
Mean
tppbj
of Hit*
0.08
—
21
35
—
57
—
49
62.4
51.9
8.0
10.8
•
95% Upper*
Confidence.:.;.
Limit Mean
'•':••
-------
Table 10
43
Table 7-6
Pe*tWde» (Surface Witar /Sediment)
Phue II-A, (I-B, m
PARAMETER
Alpha - BHC
beta- BHC
gamma - BHC
delta • BHC
Aldrin
Dialdrin
4,4' ODD
4,4' ODT
4,4* DOE
£ndrin Ketane
Heptachlor
Toxaphene
-------
44
analyses. Many of the contaminants identified during the RI
occurred at low frequency and/or in very low concentrations
relative to the practical quantification limit for each compound.
The selection of contaminants that would be fully evaluated during
the Baseline Risk Assessment in order to quantify Site risks were
selected in accordance with guidance as contained in the document
Risk Assessment Guidance for Superfund (RAGS), EPA/540/1-89/002,
12/89. The selection process included the following criteria: (1)
the chemical has demonstrated significant toxicity to animal life
in published reports, (2) USEPA health-based numbers can be
obtained for the chemical, (3) whether its occurrence is
significant, based on frequency, concentration and exposure
potential, in regard to the total risk posed by the Site. The
rationale used for selection of the evaluated contaminants and for
eliminating the other contaminants is provided in the. following
discussions.
The selected contaminants of concern for the baseline risk
assessment are shown in Table 4. Pesticides were the primary
hazardous contaminants detected. In addition, a limited number of
semi-volatile, volatile, and inorganic parameters were identified
and will be carried through the baseline risk assessment process as
explained below. Only Contract Laboratory Program (CLP) data were
used for the evaluation of baseline risk at the Helena Chemical NPL
Site.
In soils, DDT (plus DDE and DDD) , BHC (all isomers) , toxaphene and
dieldrin were the most frequently detected and generally were found
in the higher concentrations. Aldrin, endosulfan sulfate, endrin
and endrin ketone were the next most frequently detected
pesticides. Endosulfan, heptachlor, heptachlor epoxide,
methoxychlor, and chlordane were the least frequently detected.
Disulfoton and tributylphosphoro-trithioate (TBPT,
butylphosphorotrithioate) were also detected infrequently, but were
nonetheless evaluated as part of the BRA. Due to the low frequency
of detection and the relatively low concentrations of heptachlor,
heptachlor epoxide and chlordane (both isomers) found in site
soils, these compounds were not evaluated as part of the BRA as it
was determined that they would not contribute significantly to the
overall risk posed by the site. This approach is consistent with
the process for eliminating compounds from further consideration as
outlined in RAGS. Endosulfan sulfate and endrin ketone are not
listed in EPA databases which contain Agency reviewed toxicity
data, and as a result the reference doses (RfD's) of their parent
compounds {endosulfan and endrin, respectively) were used to
compute the risk posed by these compounds. This procedure provided
a conservative estimate of risk (or hazard index).
A large number of inorganic parameters were detected in soil
samples. No inorganic contamination associated with site
activities was found, however, in soils at a frequency and/or
-------
45
concentration sufficient to warrant consideration as a contaminant
of concern.
Site-related contamination was identified in the surface water
samples gathered during the RI. An evaluation of this data
indicates that pesticides are the only hazardous substances
detected at significant concentration and frequency in this medium
to warrant further consideration. Due to the intermittent nature
of the surface water on-site, this medium was not considered a
significant pathway for direct human exposure.
In groundwater, aldrin, BHC (all isomers), DDT (plus DDE & DDD),
dieldrin, and endrin ketone were detected in the highest
concentration or frequency, and represent the contaminants of
concern from the groundwater perspective. Other detected
chlorinated pesticide compounds included endosulfan II, endrin,
toxaphene, endosulfan sulfate, and heptachlor epoxide. With the
exception of heptachlor epoxide, these compounds were also
evaluated in the Baseline Risk Assessment (BRA). Heptachlor
epoxide was detected in one groundwater sample during Phase II-A.
It has not been detected in any other sample during subsequent
groundwater sampling events. As a result, heptachlor epoxide was
not considered a contaminant of concern for the groundwater
pathway. Heptachlor epoxide was therefore not evaluated as part of
the BRA process. TBPT was also detected in one groundwater sample
during the 3rd Quarter 1991 groundwater sampling event. Disulfoton
was detected in two groundwater samples from the 4th Quarter 1991
sampling event and was evaluated as a contaminant of concern in
groundwater. Benzene, lead, and chromium were also detected in
groundwater samples. The frequency of detection and concentration
for these parameters was generally higher than for the pesticide
compounds and they were evaluated due to their potential
contributions to overall risk (or hazard index).
Carbon disulfide was not consistently detected between RI phases.
As a result, carbon disulfide results were attributed to laboratory
artifacts, and were not evaluated further. Although bis{2-
ethylhexyl)phthalate (BEHP), acetone, methylene chloride, and 2-
butanone were identified in a significant number of samples, they
were not evaluated as contaminants of concern. These compounds are
common exogenous contaminants attributable to sampling methods
and/or laboratory artifacts, and are not related to current or
former site operations.
Numerous polynuclear aromatic hydrocarbons (PAHs) and phenolic
compounds were identified in soil and groundwater during RI Phase
II-A. These compounds were detected at low frequencies and at
concentrations at or near their respective practical quantitation
limits. Subsequent to Phase II-A, the semi-volatile contaminants
of concern were limited to tentatively identified compounds (TICs)
identified during Phase II-A. The TICs were disulfoton, TBPT, and
chlorobenzilate. As a result, the BRA focused on the TICs and
-------
46
Figure 5
flour* 7.3
Equation* for Calculating Oral and Dermal
^Chronic .Expoaur* LavaU from .
HCFSC Site Sole
Future She R**iderrt» and Currant She Worker*
FUTURE SITE RESIDENTS
SOIL INGESTION PATHWAY
Age-adjusted Ingestion Factor (IF_M,)
'F—u.* Img-yr/kg-day) = IR_,. ,j x ED..
BW..
° _•!»>•
where:
age-adjusted soil ingestion factor (mg-yr/kg-day)
average body weight from ages 1-6 (kg)
average body weight from ages 7-31 (kg)
exposure duration during ages 1-6 (yr)
exposure duration during ages 7-31 (yr)
ingestion rate of soil age 1 -6 (mg/day)
ingestion rate of soil age 7-31 (mg/day)
age-adjusted ingestion factor (mg-yr/kg-day)
Default Values
109 mg-yr/kg-day
16 kg
70kg
6 years
24 years
200 mg/day
100 mg/day
109 mg-yr/kg-day
DERMAL CONTACT PATHWAY
Age-adjusted Contact Factor (CF_, ^,)
i (mg-yr/kg-day)
BW..,,,
.,^ x AF x ED.,..
where:
AF
age-adjusted contact factor (mg-yr-event/kg-day)
skin surface area available for contact (cm'/event)
skin surface area available for contact (cm'/event)
soil to tkin adherence factor (mg/cm2)
exposure duration during age 1-6 (yr)
exposure duration during age 7-31 (yr)
3400 mg-yr-event/kg-day
2430 cm'/event
2300 cm'/event
2 mg/cm1
6yr
24 yr
COMBINED DAILY ABSORBED DOSE
Non-Careinogena
Daily Absorbed Dose «=
(I
((CF^ ,^xC.x10^g/mg x EF, x
Carcinogena
Daily Absorbed Doee =
((IF— /-ixC.x10-
-------
47
Figure 5 (continued)
' Equation* :for Catenating Oral and Dsvmai -•
Crronic Exposure Lmvi* from : •':.-'•'"•" -''-,'•
HCFSCSteSo**: : -; : ;
Future SHe Residents end Current She Workers
where:
C.
EF,
ATMC
ATC
ABS'
Chemical concentration in soil
Residential exposure frequency
Averaging time (non-carcinogen)
Averaging time (carcinogen)
Absorption factor (unitless)
Default Values
chemical-specific
350 days/year
10,950 days
25.550 days
0.01
CURRENT SITE WORKERS
COMBINED SOIL INGESTION AND DERMAL CONTACT PATHWAYS DAILY ABSORBED DOSE
Non-Carcinogens
Combined Chronic Absorbed Dose =
(OR-.—., x C, x 10" kg/mg x EFW x EDJrtBW. x
((C. x 10* kg/mg x ABS x AF x SAW x EF. x EDJ/IBW. x A
Carcinogens
Combined Chronic Absorbed Dose =
C. x 10-* kg/mg x EF. x EDJ/1BW. x ATC.^,J)
(1C. x 10* kg/mg x ABS x AF x SAW x EF, x EDJ/IBW. x ATt _ .))
where:
ED.
BW,
AT«..
ATC_
ABS
AF
SA.
Worker toil inflection rate (mg/day)
Soil contaminant concentration (mg/kg)
Worker exposure frequency (days/year)
Worker exposure duration (years)
Worker body weight (kg)
Worker averaging time-non-carcinogen (days)
Worker averaging time-carcinogen (days)
Absorption factor (unitiess)
Soil to skin adherence factor (mg/cm1)
Skin surface area available for contact (ccrf/event)
Default Values
100 mg/day
Chemical-specific
250 days/year
30 years
70kg
10,950 days
25,550 days
0.01 ••
2 mg/cm2
2300 cm'/event
-------
48
Figure 6
Equations For Calcualtion Of Chronic Exposure
:., For The Groundwater Pathway* :
FUTURE SITE RESIDENTS
Non-Carcinogenic
Chronic Absorbed Dose from Groundwater =
Cw x IR^ x EF x ED/IBW x ATNC)
Carcinogenic
Chronic Absorbed Dose from Groundwater =
Cw x IRw.tl, x EF x ED/(BW x ATC)
Where: Default Values
C_ Groundwater contaminant concentration (mg/liter) Chemical-specific
IR,.W Groundwater ingestion rate (1 /day) 2 liter/day
EF Groundwater exposure frequency (days/year) 350 days/year
ED Residential exposure duration (years) 30 years
BW Body weight (kg) 70 kg. \ —
ATNC Averaging time for non-carcinogens (days) 30 years x 365 d/yr = 10,950 days
ATC Averaging time for carcinogens (days) 70 years x 365 d/yr = 2S,5SO days
a - Default exposure assumptions value* referenced from USEPA, RAGS, 12/89 and OSWER Directive #9285.6-03.
Note: Assume absorbed dose to equivalent to intake/ingested dose.
Cancer Risk = Carcinogenic Chronic Absorbed Dose x Slope Factor
Hazard Index = Non-Carcinogenic Chronic Absorbed Dose/RfD
-------
49
eliminated PAHs and phenolic compounds from further considerationon
the basis of low detection frequency and low concentration.
6.2 EXPOSURE ASSESSMENT
Contaminated media at the Site include surface and subsurface soil;
shallow groundwater; and surface water and sediments in on-Site and
adjacent wetlands. Pathways involving air as a medium were not
considered due to the extensive grass and vegetative cover at the
Site, and the lack of positive results from air monitoring for
Site-specific contaminants.
Populations that could potentially be exposed to Site contaminants
under current exposure conditions are on-Site workers and
occasional trespassers. Potential future land use exposure
scenarios include child and adult residents living on the Site, and
children and adults living near the Site who might visit or play on
the Site.
Based on these potential receptors, three general exposure pathways
were selected for numerical risk quantification:
1. Current exposure of adult non-residents (Site workers and
trespassers) to contaminants in surface soils through
incidental ingestion and dermal contact.
2. Future exposure of on-site adult and child residents to
contaminants in shallow soils through incidental ingestion and
dermal contact.
3. Future exposure of onsite adult and child residents to
contaminants in groundwater through ingestion.
In order to quantify the exposure associated with each pathway,
various standard procedures were used to determine key variables in
the exposure calculations. These variables include the contaminant
level in the medium, usually referred to as the exposure point
concentration; and the amount of the chemical taken into the body,
or chronic daily intake, which must be calculated using a number of
assumptions. Since EPA policy is that exposure estimates must
approximate a Reasonable Maximum Exposure (RME) scenario, each of
the variables was selected with the goal of producing the maximum
exposure that could reasonably be expected to occur. Tables 13 and
14 present the exposure point concentrations calculated for the
contaminants of concern in soils and ground water. It should be
noted that the mean concentrations for each contaminant detected in
the "hot spots" were used as the exposure point concentrations in
the RME evaluation.
Calculation of average daily intake requires input of numerous
exposure parameters which are usually applicable to a particular
-------
50
Table 11
' % '- •,"••*"*& -"f^^'i ' v.-TaH«7-13 J*i<>'-- '
Groundwatar Contaminant Lavvta
-------
Table 12
51
f ,- ^ s.-'. s~rt'
Sol Contaminant Laval* (mg/kg) Yielding 1O*to 1C*
vUppcr Bound Risk tavsb f or Fuuvv R«uiinit Expovur* Scwiwio* vt th« HCFSC Srta
Potential Futu-* Site R*«U*nt
Curcnt Upper
Bound K«k Level
Notes: No compound presented a hazard index in excess of 1; a linear relationship exists batween soil concentration and
associated risk levels, therefore the cleanup objectives for each risk level may be computed by determining the
following:
X (Soil Cleanup Goal) = Risk Level Goal x Current Soil Concentration/Current Rick Level
NA No Slope Factor for the compound.
— Current contaminant levels in soil do not present a risk in excess of the respective risk levels.
-------
52
exposure pathway. The exposure parameters used for soils
aresummarized in Figure 5. The same parameters for ground-water
exposure are shown on Figure 6.
The result of the exposure assessment is a set of tables showing a
calculated average daily intake value for each chemical or
compound, as well as a summary value for each exposure pathway.
Tables 13 and 14 contain these data and summaries.
6.3 TOXICITY ASSESSMENT
In this portion of the Baseline Risk Assessment, the toxic effects
of contaminants were investigated and evaluated. The critical
variables needed to calculate estimates of risk were obtained from
the EPA toxicological databases. Critical toxicity values for
Helena Chemical Site contaminants are presented in Table 15.
Slope factors (SFs) have been developed by EPA's Carcinogenic
Assessment Group for estimating lifetime cancer risks associated
with exposure to potentiall carcinogenic contaminants of concern.
SFs, which are expressed in terms of (mg/kg-day)"1, are multiplied
by the estimated intake of a potential carcinogen in order to
provide an upper-bound extimate of the excess lifetime cancer risk
associated with exposure at that intake level. The term "upper
bound" reflects the conservative estimate of the risks calculated
from the SF. Use of this approach makes under-estimation of the
actual cancer risk highly unlikely. Slope factors are derived from
the results of human epidemiological studies or chronic animal
bioassays; if animal bioassays are used, animal-to-human
extrapolation and uncertainty factors are applied to account for
the use of animal data to predict effects on humans. The SFs for
the carcinogenic contaminants of concern are contained in Table 15.
Reference doses (RfDs) have been developed by EPA for use in
indicating the potential for adverse health effects from exposure
to contaminants exhibiting noncarcinogenic effects. RfDs, which
are expressed in units of mg/kg-day, are estimates of lifetime
daily exposure levels for humans, including sensitive individuals
or subpopulations. Estimates intakes of contaminants of concern
ingested from environmental media can be compared to the RfD. RfDs
are derived from human epidemiological studies or animal studies to
which uncertainty factors have been applied, to account for the use
of animal data to predict effects on humans. The RfDs for the
noncarcinogenic contaminants of concern are also contained in Table
15.
Carcinogenic contaminants are classified according to EPA's weight-
of-evidence system. This classification scheme is summarized
below:
Group A: Known human carcinogen.
-------
53
Table 13
'»-•-,> -h, , ." ~r,Af^\. v, , .
1, ' .Tabta 7-9
Summary of Risk* forfutm Stte Ra*idant Direct IngwtioiY of GraundwaurV
. " ' ' ' ' HCFSCSits ' ' ' ~*
Parameter
Aldrin
alpha-BHC
bata-BHC
delta-BHC
gamma-BHC
DDT
DDD
DDE
Dieldrin
Endosulfan II
Endrin
Endrin Ketone
Toxaphene
Endosulfan Sulfate
Disulfoton
TBPT
Benzene
Lead
Chromium
95% UCLk
(ppbl
O.266
3.44
3.74
1.06
0.69
0.175
0.24
0.21
1.11
0.13
0.081
2.98
8.29
0.091
9.12
10.7
6.85
11.5
69.75
Slop*
Factor
(SFT
17
6.3
1.8
NA
1.3
0.34
0.24
0.34
16
NA
NA
NA
1.1
NA
NA
NA
0.029
NA
NA
Reference Dos*
IRfDr
0.00003
NA
NA
NA
.0003
0.0005
NA
NA
0.00005
0.00005
0.0003
0.0003'
NA
0.00005'
O.OOO04
NA
NA
0.0014'
1.0
:- ".*
::•-•-:'
Sum of Cancer Risks and Hazard Indices'
Upper Bound
Cancer Risk*
5.32E-5
2.54E-4
7.90E-5
NA
1 .05E-5
7.00E-7
6.75E-7
8.31E-7
2.08E-4
NA
NA
NA
;.i. 1.07E-4
NA
NA
NA
1 .99E-6
NA
NA
4ZR!sfc--7.1E.4:~.
Hazard Index'
0.24
NA
NA
NA
0.063
0.0096
NA
NA
0.61
0.073
0.0073
0.27
~~NA
0.050
6.25
NA
NA
0.23
8.19E-4
..•:::T:HI-::7,80:::::-;
a - assume* consumption of 2 liters/day of contaminated groundwater (at 95% UCL for each parameter) over
a 70 year period for carcinogens and a 30 year period for non-carcinogens.
b - Rgure 7-2 provides the equations used to compute chronic daily intake for establishing risk levels and hazard
indices.
c - 95% Upper Confidence Limits means calculated using detected values for hits and one-half the sample
quantitation limit for non-hits. Data used was derived from the 3rd end 4th Quarter 1991 Groundwater
Sampling Events.
d - RfD for endrin applied to endrin ketone; RfD for endosulfan applied to endosulfan sulfate.
e - The unit risk for lead is calculated from a treatment technology based MCL of 0.015 mg/l. A USEPA
approved RfD for lead has not been established.
f Hazard Indices have been summed as a conservative estimate of non-carcinogenic risk; generally summation
of Hazard Indices is appropriate only for contaminants having the same target organ effect (for non-
carcinogens).
-------
54
Table 14
,:".!"" ^.v" ;; • - •yra*»-:7-to •' . • ; .
..,...,•:. Summary of Ri*k> for Cwrent Adtrft Worker* and Ftntr* 6ita Residents .
• from Oral and Dermal Exposure to Contaminants in Sbl/Sadinienti
•• •. ..'•••<< ' • * HCFSCSttn
Concentration of
Contaminant
(mg/kg)"
1.59
0.53
0.75
0.38
0.034
19.2
6.45
0.91
2.69
«
1.82
1.92
0.65
0.22
3.3
43.3
0.097
0.0
Contaminant
Aldrin
olpha-BHC
beta-BHC
delta-BHC
gamma-BHC
DDT
ODD
DDE
Dieldrin
Endosulfan
Endosulfan Sulfate
Endrin
Endrin Ketone
Methoxychlor
Toxaphene
Disulfoton
TBPT
Sum of Upper Bound Cancer Risk . :
Sum of Hazard Indices •
Future Resident Upper
Bound Risk Level*
(or Hazard Index)
5.3E-5
(HI =0.0243)
6.5E-6
2.65E-6
NA
8.68E-8
(HI =0.00052)
1.28E-5
(Hl=0.176)
3.04E-6
6.07E-7
8.45E-5
(HI =0.246)
(HI =0.1 67),: ',
(Hl=0.176)
(HI =0.0084)
(HI =0.0034)
(HI =0.003)
9.35E-5
(HI =0.011)
NA
-' -:; : 2S7&4"-'v-"":::-.'-;""
Sum:ofHI = .82..:
Adult Worker Upper Bound
Risk Level*
(or Hazard Index)
1.56E-5
(HI =0.076)
2.0E-5
8.3E-7
NA
2.7E-8
(HI = 1.6E-4)
4.0E-6
(Hl = 0.055)
9.5E-7
1.9E-7
2.6E-5
(HI = 0.0771
(HI =07052)
(HI =0.055)
(HI = 2.6E-3)
(HI = 1.1E-3)
(HI = 9.4E-4>
2.92E-5
(HI =0.0035)
NA
8.0E-5
Sum of HI =0.32
Notes:
a Mean concentration in soil (95% C.L. was not calculated as the data are not normally distributed). The mean
contaminant concentrations in the "hot spots" onsite were assumed to be present over the entire site area. Uniform
exposure to all arees onsite was assumed to provide a conservative estimate of exposure. This approach is consistent
-with USEPA, Region IV guidance for establishing RME levels.
b HI (Hazard Index) of > 1 is a cause for concern. Upper bound risk levels of 10"* to 10* are considered on a case-by-
case basis as to their acceptability by the USEPA.
c TBPT was not identified in surface soils onsite.
NA Not applicable
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55
Table 15
,~,v -„<(*, ^« * X, £g~*~. -J,^
* 2 < .,» *- »-^.r '
«. >T !.--•«-,
orate
Contaminant
Chlordane
Endrin
Heptachlor
Heptachlor Epoxide
Oisulfoton
Benzene
Aldrin
e-BHC
B-BHC
gamma-BHC (Ljndane)
delta-BHC
Dieldrin
Endosulfan
ODD
ODE
DDT
Toxaphene
TBPT*
Mathoxvchlor
Chlorobenzilata
Chromium'
Lead
' " .Tabt»;
H«ah»*eaaad Value* for C
TNoncarcmogans {RfD
ipo«ur« to Contaminants o
Sjopcf actor :(SR
(mg/kg/dayr*
1.3
NA
4.5
9.1
NA
0.029
17
6.3
1.8
1.3
NA
16
NA
0.24
0.34
0.34
1.1
NA
NA
NA
NA
NA
N» *?-**•
-aicinog«n» (CPF) «od
JandARARafar
f Concern rt the HCF5C Site
fWD
(mg/kgyday)
O.OO006
O.OO03
O.O005
0.000013
0.00004
NA
0.00003
NA
NA
0.0003
NA
0.00005
O.OO005
NA
NA
O.OO05
NA
NA
O.OO5
0.02
1.0
0.0014"
•-..:; • •-..: •%,,. .
ARAR
(MCt ac mg//)
0.002
0.002'
0.0004
0.0002
NA
0.005
NA
NA
NA
0.0002
NA
NA
NA —
NA .
NA
NA
0.003
NA
0.04
—
0.1
0.015'
a A proposed MCL of 0.002 mg//
b No verified risk based criteria exist for TBPT.
c The unit risk for lead is calculated from a treatment technology based MCL of 0.015 mg/l. A USEPA approved RfD for
lead has not been established.
d based on assumption that all chromium is present in the (III) valance state.
e % unit risk computed from MCL
NA Not available or not determined
Slope Factor synonymous to Cancer Potency Factor (CPR
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56
Group Bl: Probable human carcinogen, based on limited human
epidemiological evidence.
Group B2: Probable human carcinogen, based on inadequate
human epidemiological evidence but sufficient
evidence of carcinogenicity in animals.
Group C: Possible human carcinogen, limited evidence of
carcinogenicity in animals.
Group D: Not classifiable due to insufficient data.
Group E: Not a human carcinogen, based on adequate animal
studies and/or human epidemiological evidence.
6.4 RISK CHARACTERIZATION
It should be noted that there is some degree of uncertainty
associated with the calculated numerical estimates of human health
risks generated in the Baseline Risk Assessment. This is due to
the considerable number of assumptions required to provide
variables in the equations, and the specific selections of each
variable from a range of possibilities. The potential risk
associated with soils and groundwater exposure was quantified
through the standard risk assessment scenarios (Tables 13 and 14) .
6.4.1 Ground Water
Ground-water risk based upon residential drinking water.exposure
was evaluated as a potential future risk. Samples from several
monitoring wells had at least one contaminant that exceeded the
current MCL.
Table 13 presents the individual risks associated with each
parameter found in ground water along with total carcinogenic and
non-carcinogenic values. The total groundwater risk for future
residents consuming water from the surficial aquifer was calculated
at 7.1 x 10"4. The summation of the Hazard Indices for the future
groundwater exposure scenario was calculated at 7.8. Toxaphene,
dieldrin and alpha-BHC account for 80 percent of the carcinogenic
risk, Disulfoton accounts for 80 percent of the non-carcinogenic
risk. These values indicate that significant carcinogenic and
noncarcinogenic risk may be posed by consumption of contaminated
groundwater from a potable water well located onsite. The
assumptions upon which these risk levels were based are
conservative.
The groundwater risk levels were computed using the 95 percent
Upper Confidence Limit of the mean from each well for each
parameter. The 95 percent Upper Confidence Limit was computed
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57
using detected values for hits and one-half the sample quantitation
limit for non-detects. The mean value for each groundwater
monitoring well (for the 3rd and 4th Quarter 1991 sampling events)
was used. This more rigorous statistical approach for computing
the Reasonable Maximum Exposure (RME) was used due to the greater-
uncertainty associated with the distribution of contaminants in the
groundwater medium.
Under current circumstances, contaminants attributable to the site
pose no imminent carcinogenic or non-carcinogenic risk to site
workers or area residents through the groundwater exposure pathway.
The adjacent municipal potable water well is screened in a deeper
saturated zone separated by a possible aquitard from the
contaminated aquifer. The municipal well has been tested, and no
site constituents have been detected in the potable source.
Residences within the groundwater contaminant plume . area are
connected to the municipal water system rendering private wells
unnecessary.
In light of these factors, future resident exposure through the
groundwater pathway may be minimized through control of the limited
shallow aquifer contamination. Control would serve to reduce
contaminant levels in the shallow aquifer (with concurrent
reductions in the future resident groundwater onsite exposure risk
potential), and would prevent migration of contaminants to the
unaffected deep aquifer supplying the nearby municipal well.
Surface water is not considered a significant pathway for direct
human exposure.
6.4.2 Soils
Direct soil exposure poses a pathway of significant reasonable
potential risk (current and future). Upper bound cancer risk and
toxicity hazard index values were calculated for the contaminants
of concern. A summary of these calculated values is shown in Table
14.
The soil samples indicated that soils had a wide range of
contaminant levels with rather defined areas of greater contaminant
concentration (north and northeast portions of the Site). The vast
majority of Site contamination exists within an area from the north
warehouse building onsite to 300 feet north and northwest of this
warehouse building. Careful perusal of the data gathered during
the RI reveal approximately 30% of the Site's total soil area is
contaminated with total pesticide levels greater than 100 ppb.
Volatiles in soils tend to be in these same areas (warehouse and
old landfill) but only constituted 20-25% of the total area. Soil
contaminant mean concentrations were computed using the 'hot spot'
method where only those samples with detectable contaminant
concentrations were included in the calculations. The total area
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58
of the 'hot spots' encompasses approximately 30 percent of the
entire site area. In order to provide a conservative exposure
estimate, the computed mean concentration of each contaminant (from
'hot spots') was assumed to exist over 100 percent of the site.
This approach is consistent with EPA guidance for establishing
reasonable maximum exposure (RME) levels.
Throughout most of the year, site sediments are not submerged, and
as a result, present the same exposure pathways as site soils;
Sediment contaminant concentrations were within the range observed
in site soils. Therefore, no differentiation was made between soil
and sediment for risk computation purposes for the ingestion and
dermal contact pathways.
In order to provide a conservative estimate of the potential risk
posed by the direct ingestion and dermal contact soil exposure
pathways, the following exposure scenario assumptions were applied^
The potential for direct soil ingestion or dermal contact with
soils is greatest for those soils closest to ground surface. As a
result, the arithmetic mean was computed for each constituent of
concern using soil concentrations from samples collected within one
foot of ground surface. The distribution of pesticide contaminants
indicated that higher concentrations for an area are generally
present at the surface. Only positive results were used for the
calculation of mean contaminant concentrations in soil. As a
result, the mean values calculated (and used for calculation of
chronic daily intakes) were biased toward the higher range of all
values observed for soils. This approach is consistent with the
'hotspot' approach discussed in USEPA, RAGS, 12/89.
In addition for purposes of calculating carcinogenic risk (or
hazard index) , it was assumed that the computed average contaminant
concentrations were present over 100 percent of the site. It was
also assumed that current site workers and future site residents
would have uniform exposure to all areas onsite. This assumption
is conservative in that current site operations are restricted to
approximately 25 percent of the site area. Highly contaminated
soils are concentrated north and northeast of the north warehouse;
The current operations area is restricted to the southern portion
of the north warehouse. Current site workers do not enter other
highly contaminated areas over the course of everyday operations.
The relevant current and potential future soil exposure scenarios
for this site are considered to be adult workers and future site
residents exposed through the combined pathway of ingestion and
dermal adsorption of contaminated soil. Trespassers would be
expected to spend a minimal amount of time on-site compared to
adult workers and therefore should be more than adequately
protected based on the occupational risk calculations.
Table 14 summarizes computed risk values (and hazard indices) for
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59
the soil direct ingestion and dermal contact exposure pathway. The
combined carcinogenic risk from surface soil contaminants is 8.0 x
lO"5 for current adult workers and 2.57 x 10~4 for future site
residents. Aldrin, toxaphene, and dieldrin account for the
majority (approximately 85 percent) of the total upper bound cancer
risk for onsite surface soils for both current adult workers and
future site residents. The sum of hazard indices is less than
unity (1) for current adult workers and 1.0 for future site
residents, using only soil exposure pathways. It is worth noting,
however, that the sum of hazard indices is generally relevant only
in instances where the target organ for each contaminant is the
same. As a result, the computed sum of hazard indices yields a
more conservative assessment of non-carcinogenic risk.
The areas directly north and northwest of the northernmost
warehouse represent the area of concern for most surface soil
contaminants. It should be noted that each individual surface soil
contaminant was assumed to be present over 100 percent of site
surface soils (at the mean concentration). In reality, each
contaminant is present in a much smaller area. The contamination
distribution assumptions and the occupational exposure duration
assumptions used in calculating risk are conservative. It should
also be noted that occupational exposures are intermittent and not
continuous. Again, the conservative assumption of continuous
exposure was used.
6.4.3 Surface Water
The surface water identified on-site is intermittent in nature, and
only exists after rainfall associated with storm events. Standing
water is generally isolated to the densely vegetated area along the
north property line. This area is not subject to recreational use,
and site workers do not have occasion to enter this area during
normal site operations. As a result, surface water is not
considered a viable exposure pathway.
6.5 ENVIRONMENTAL (ECOLOGICAL) RISKS
Surface water and sediment samples were gathered during the RI from
on-Site areas and in drainage pathways leading from the Site into
local surface water streams. These samples were shown to be
contaminated with Site-specific pesticides at levels which present
an unacceptable level of risk to environmental receptors.
Surface water samples were contaminated with pesticides at
concentrations which exceed ARARs, namely Federal Ambient Water
Quality Criteria (AWQC) and State of South Carolina ambient
standards for surface waters. The AWQC and state standards have
been established based upon protection of aquatic life from adverse
effects of exposure to toxics, and it is presumable that
concentrations which exceed these criteria and standards will have
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an unacceptable adverse impact on environmental receptors.
Sediment samples were also found to be contaminated with Site-
specific pesticides. There are no promulgated standards or
criteria for sediment quality at either the State or Federal level,
so no ARARs exist for sediment quality. Considerable research has
been conducted, however, on the environmental effects of exposure
to contaminated sediments. This research has been compiled by the
National Oceanographic and Atmospheric Administration (NOAA), in
the document entitled The Potential for Biological Effects of
Sediment-Sorbed Contaminants Tested in the National Status and
Trends Program. NOAA Technical Memorandum NOS OMA 52, August, 1991.
The levels of sediment contamination found at this Site exceed the
levels cited in this document as being likely to contribute to
adverse impacts to biological receptors.
7.0 DESCRIPTION OF REMEDIAL ALTERNATIVES
The Feasibility Study (FS) considered a wide variety of general
response actions and technologies for remediating soil and
groundwater. Based on the FS, Baseline Risk Assessment, and
Applicable or Relevant and Appropriate Requirements (ARARs), the
remedial action objectives (RAOs) listed below were established for
the Site. Alternatives were developed with the goal of attaining
these objectives:
Groundwater - EPA believes that active remediation of groundwater
(such as a groundwater pump and treat system) in the Barnwell
formation underlying the Site is a practicable and appropriate
response. The Barnwell Formation is classified under the EPA
Guidelines for Ground-Water Classification as a Class IIB ground
water, ie., a potential source of potable water supply. These
ground waters also are classified as Class GB waters of the State.
The contamination at the Site has resulted in impairment of the
ground-water resource as a potential drinking water source due to
unacceptable risks to human health. In addition, the likelihood of
a hydraulic connection between the Barnwell Formation and the
underlying McBean/Santee Formation exists; the nearby municipal
supply well draws water from the McBean/Santee Formation. In order
to prevent migration from the existing contaminant plume into the
underlying drinking water supply aquifer, ground-water extraction
is warranted.
The remedial action objective for contaminated ground water is to
restore the affected aquifer to a condition that renders it
suitable for use as a potable water supply. Criteria based upon
protection of human health via drinking water exposure for site-
specific contaminants of concern are listed in Table 6. These
criteria constitute the remedial goals for ground water at the
Helena Site.
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Given the likelihood of a hydraulic connection between the Barnwell
and the McBean/Santee formations, and the inconclusive nature of
the pump test conducted as part of the RI, EPA anticipates that
effective implementation of the ground-water remediation at this
Site will include another pump test. The purpose of such a pump
test will be to determine the degree of interconnection between the
formations mentioned above. The exact means by which this pump
test will be conducted will be determined during remedial design
activities.
Surface and Subsurface Soils - Soils on the Site, both at the
ground surface and at depths grater than one foot, are contaminated
at levels which exceed criteria protective of human health under an
exposure scenario which assumes unrestricted land use, including
residential development, and which exceed concentrations that are
likely to continue to leach contaminants to ground water. The
overall remedial action objective for the surface and subsurface
soils is to remove and remediate contaminated soils to such a
degree that both ground-water quality (in conjunction with ground-
water extraction and treatment) and human health are protected.
The RI identified soil remediation goals for both of these
purposes. Table 7 presents a comparison of these remedial goals as
developed in the RI. EPA review of the remedial goals developed in
the RI for the protection of ground water revealed, however, that
the technical basis for these goals was inadequate. EPA therefore
conducted an independent analysis of soil contamination levels and
has determined that a soil remediation goal of 50 ppm total
pesticides is protective of human health and the environment, and
will result in the removal of 90% of the total pesticide mass that
exists at the site.
The evaluation performed by EPA was based upon contaminant
distribution data provided in the RI. EPA used this contaminant
distribution data to calculate the contaminant mass associated with
the soils at the Site as it is related to contaminant
concentrations. Contaminants migrating from a relatively
concentrated source area via soils or ground water tend to be
logarithmically distributed. By determining the concentration at
which the bulk of contaminant mass will be removed and optimizing
this concentration with relation to the volume of soil requiring
treatment (i.e., by avoiding a situation whereby the law of
diminishing returns is created), the appropriate soil remediation
goal can be estimated.
The proposed remedial action would then consist of treating the
soils by a combination of bioremediation and hydrolytic/photolytic
dechlorination (HPD), and replacement of the treated soils in the
on-site excavations, followed by covering the backfilled material
with one foot of clean soils. The performance standards for
treatment of the soils would satisfy the Land Disposal Restrictions
(LDRs) found in 40 CFR Part 268, promulgated under the authority of
the Resource Conservation and Recovery Act (RCRA). This proposal
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is based partly upon the concept that ground-water quality can be
protected by treatment of soils in these source areas in
combination with extraction and treatment of contaminated ground
water. The removal and treatment of soils in the source areas is
also protective of human health via direct contact and incidental
ingestion.
Wetlands and Contaminated Sediments - The placement of fill
material in jurisdictional wetlands, and the contamination of the
sediments in the wetlands that resulted from this placement, have
resulted in an unacceptable level of risk to environmental
receptors. The remedial action objective for the fill and the
contaminated sediments is to mitigate for the impacts that have
resulted in these unacceptable levels of risk to environmental
receptors. Mitigation will comply with the requirements of Section
404 of the Clean Water Act, and specific mitigative measures will
be determined in accordance with the criteria and guidelines
established under Section 404(b) (1) of that Act. These regulations
are relevant and appropriate to the circumstances of the release of
contaminants from the landfill placed in jurisdictional wetlands.
The following section provides a summary of the six (6)
alternatives developed in the FS Report to address the
contamination of soils, sediments and ground water at the Helena
Chemical NPL Site. The primary objective of the FS was to
determine and evaluate alternatives for the appropriate extent of
remedial action to prevent or mitigate the migration or the release
or threatened release of hazardous substances from the Site. With
the exception of the No-Action alternative, all alternatives
include the same provision for extraction, treatment and proper
disposal of contaminated ground water. Likewise, all alternatives
with the exception of No Action have the same provision for
mitigation of the adverse effects associated with pesticide
contamination in the wetlands adjacent to the Site. While wetlands
mitigation is not discussed in the FS as a component of any of the
alternatives, EPA has determined that unacceptable levels of risk
to environmental receptors have resulted from the release of site-
specific contaminants into jurisdictional wetlands. Mitigation for
these releases has been determined to be relevant and appropriate
to the circumstances of the release under the criteria for such
determinations contained in the NCP. Alternatives 2 through 6
(Alternative 1 being the No-Action alternative) differ only in the
technologies to be applied for the remediation of contaminated
soils.
The following descriptions of remedial alternatives are summaries
of more complete descriptions found in the FS report. The FS
report contains a more detailed evaluation of each alternative and
is available for review in the Administrative Record for the Site.
All costs are based upon capital costs plus the present worth of
annual operation and maintenance costs.
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63
7.1 ALTERNATIVE 1 - NO ACTION
By statute, EPA is required to evaluate a "No Action" alternative
to serve as a basis against which other alternatives can be
compared. Under the No Action Alternative, no remedial response
would be performed on any of the media of concern (surface soil,
ground water or sediments) at the Site. This alternative does not
reduce the risk calculated by the Baseline Risk Assessment. The No
Action Alternative results in an excess cancer risk of 8.0 X 10"5
and a Hazard Index for non-carcinogenic effects of 0.3 for current
land use exposure scenarios, and an excess cancer risk of 2.6 X 10"4
and a Hazard Index for non-carcinogenic effects of 8.6 for
potential future land use scenarios.
The estimated present worth cost for the no-action alternative is
$480,000. This cost is for monitoring of ground water and soils
for thirty years.
7.2 ALTERNATIVE 2 - DEMOLISH FORMULATION BUILDINGS; CONSOLIDATE
CONTAMINATED SOILS AND DEBRIS IN ONSITE LANDFILL; GROUND-WATER
EXTRACTION. TREATMENT AND DISPOSAL; AND WETLANDS MITIGATION
All alternatives, excluding No Action, include ground-water
containment by means of extraction, treatment and appropriate
disposal. The installation of ground-water extraction wells will
prevent the migration of contaminants beyond the present extent of
the contaminant plume, and will over time remove contaminants from
the ground water lying beneath the Site. At present, the extent of
contaminated ground water is confined to the shallow aquifer (the
Barnwell Formation) and does not appear to extend laterally to off-
site areas.
Extracted ground water will be treated to criteria appropriate for
the final means of disposal. At present, it is planned that the
extracted ground water will be treated and discharged to the local
sanitary sewer system, also known as a POTW. Pretreatment
requirements will be set by the owner/operator of that sanitary
sewer system in order to insure that the discharge permit for the
system will not be violated. It is possible, based upon initial
estimates of ground-water quality, that no pretreatment will be
necessary; for the purposes of preliminary cost estimates, however,
it is assumed that some degree of pretreatment for extracted ground
water will be required. The actual technologies to be employed
will be based upon the pretreatment criteria established by the
owner/operator of the POTW.
Extraction of contaminated ground water will continue until the
ground-water remediation goals are met throughout the extent of the
plume. Should it prove to be technically impracticable to achieve
these remedial goals, EPA will amend the ROD to reflect any changes
in remediation criteria.
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64
All alternatives, with the exception of No-Action, also include the
demolition of on-site buildings as necessary to remove contaminated
soil for treatment. Testing of the demolished buildings will be
conducted during remedial design in order to determine the
appropriate methods of disposal for demolition debris. It is
likely that the demolition debris will not be significantly
contaminated, so that no special handling will be required,
allowing disposal of the demolition debris as non-hazardous solid
waste.
All alternatives, with the exception of the No-Action Alternative,
also include mitigation for contaminated soils and sediments in the
wetland areas adjacent to the Site and downstream can be
accomplished in a number of ways under the regulations, guidelines
and criteria established under Section 404 (b) (1) of the Clean Water
Act, which is an ARAR for the remedial action at this Site. The
exact form of mitigation that will satisfy the requirements of this
ROD will also conform with the Memorandum of Agreement (MOA)
between the Corps of Engineers and EPA which took effect on
February 7, 1990. This MOA is a criterion "to be considered" in
the determination of remedial actions for the Site. Removal of the
fill placed in the affected wetlands, accompanied by removal of the
contamination that has resulted from transport of toxic materials
from that fill, is one potential method. Another would be the
restoration of degraded wetlands at some off-site location.
Another possibility is the acquisition of unaffected wetlands that
are currently threatened by development or other destructive
activities and placing those wetland areas in a protected status.
A number of factors will be used to determine the most cost-
effective and environmentally sound manner in which compliance with
the mitigation guidelines will be achieved.
Alternative 2 calls for the demolition of the former formulation
buildings on the Site, excavation of contaminated soils and
disposal of contaminated soil in an on-site landfill constructed
especially for this purpose. All soils exceeding 50 ppm total
pesticides would be placed in the landfill. The landfill would be
constructed to meet all applicable technical requirements regarding
design of such landfills, including top and bottom liners to
prevent infiltration of rainfall and also to prevent any further
contamination of ground water. Long-term maintenance of the
landfill would be required as part of the implementation of this
alternative.
The estimated cost for this alternative is $5.5 million.
7 .3 ALTERNATIVE 3 - DEMOLISH FORMULATION BUILDINGS. EXCAVATION AND
ON-SITE BIOLOGICAL TREATMENT OF CONTAMINATED SOILS. GROUND-WATER
EXTRACTION. TREATMENT AND DISPOSAL. AND WETLANDS MITIGATION
The ground water and wetlands portions of this alternative are
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65
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, contaminated soils containing greater than
50 ppm total pesticides would be treated on-site by means of
biological degradation. Biological degradation would take place in
treatment cells constructed on-site that would be lined to prevent
any leaching of contaminants to ground waters underlying the Site.
Biological treatment cells would consist of lined pits into which
the contaminated soils would be placed. Once placed into the
cells, moisture content, temperature and nutrient levels would be
adjusted and maintained to maximize the rate of biological
activity. Both aerobic and anaerobic conditions are envisioned in
order to maximize the effect of biological degradation.
Anticipated treatment would consist of anaerobic treatment,
particularly for soils contaminated with DDT, followed by aerobic
treatment. Some of the Site soils may require aerobic treatment
alone.
Treatability studies would be conducted to determine if this
alternative can achieve the remedial goals, but preliminary data
indicate that significant reductions in concentration of many site-
specific contaminants can be achieved by biological degradation.
Once soils are treated to the remedial goals, they would be
replaced in the on-site excavations from which they were removed:
The performance standard for treatment would be based upon the LDRs
for site-specific contaminants.
The estimated cost for this alternative is $8.0 million
7.4 ALTERNATIVE 4 - DEMOLITION OF FORMULATION BUILDINGS.
EXCAVATION AND HYDROLYTIC / PHOTOLYTIC DECHLORINATION OF CONTAMINATED
SOILS. GROUND-WATER EXTRACTION. TREATMENT & DISPOSAL. AND WETLANDS
MITIGATION
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and -disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, contaminated soils containing greater than
50 ppm total pesticides from the Site would be treated by means of
hydrolytic/photolytic dechlorination (HPD) of the pesticide
contaminants. This process would be implemented at Helena Chemical
by mixing contaminated soils with chemical reagents and exposing
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66
them to heat and ultraviolet (UV) radiation. The mixing process is
necessary to distribute the reagents (usually hydrated lime,
possibly supplemented by sodium hydroxide) throughout the mass of
contaminated material. The mixed material/reagent mass is then
placed in thin layers in cells similar to those proposed for
biological treatment in order for the soils to be exposed to heat
and UV energy from the sun. The soil mass would also be kept moist
in order to enhance biodegradation of any organic end products
resulting from the hydrolytic/photolytic dechlorination process.
Soils would be periodically "turned over" to maximize contaminant
exposure to UV radiation. The performance standard• for the
treatment process would be the LDRs for site-specific contaminants.
Treatability studies would also be required to determine if this
technology would be capable of achieving the required performance
standards.
The estimated cost for this alternative is $7.2 million.
7.5 ALTERNATIVE 5 - DEMOLISH FORMULATION BUILDINGS. EXCAVATION.
HYDROLYTIC/PHOTOLYTIC DECHLORINATION AND BIOLOGICAL TREATMENT OF
SOILS ON-SITE. GROUND-WATER EXTRACTION. TREATMENT AND DISPOSAL. AND
WETLANDS MITIGATION
This is the preferred alternative for remediation of the Helena
Site.
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, the two technologies discussed under
Alternatives 3 and 4 above would be combined in order to take
advantage of the particular benefits of each. Past studies and
experience with biological treatment have indicated that biological
treatment alone is effective for many of the site-related soil
contaminants at Helena (notably DDT and its metabolites) ,
Biological treatment alone, however, is less effective for
toxaphene, which is another Site contaminant found in significant
concentrations, likewise contributing significantly to the risk
associated with Site exposure. HPD, on the other hand, has been
shown in pilot-scale studies to be effective in the destruction of
toxaphene. The two technologies would be combined in a treatment-
train mode, with HPD treatment followed by biological treatment.
In addition to biological treatment of site-specific contaminants
other than toxaphene, the second step of the treatment train would
also serve to further degrade the breakdown products produced by
the initial HPD step.
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Otherwise, the treatment processes would be as described under
Alternatives 3 and 4, above. The soil remediation goal would
remain at 50 ppm total pesticides, and the treatment performance
standard would be based upon the LDRs for site-specific
contaminants. The estimated cost for this alternative is $3.9
million.
7 . 6 ALTERNATIVE 6 - DEMOLISH FORMULATION BUILDINGS, EXCAVATION AND
LOW TEMPERATURE THERMAL DESORPTION OF SOILS ON-SITE. GROUND-WATER
EXTRACTION. TREATMENT AND DISPOSAL, AND WETLANDS MITIGATION
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, contaminated soils exceeding 50 ppm total
pesticides from the Site would be treated on-site by means of low
temperature thermal desorption (LTTD). This process -involves
processing contaminated soils through a rotary dryer or kiln. The
soil mass is heated to a temperature level that is sufficient to
drive the contaminants off of the soil matrix, but not high enough
to actually incinerate or destroy the contaminants. Soil
contaminants are volatilized from the solids and purged from the
kiln or dryer by means of an inert purge gas. After the purge gas
leaves the desorption unit, it is treated by an off-gas treatment
system that prevents the soil contaminants from being released into
the environment. Typical air pollution control equipment (such as
cyclonic precipitators and baghouses) are also used to protect air
quality during operation of desorption units.
LTTD typically concentrates the Site contaminants into a low-
volume, highly concentrated waste stream that must in turn be
disposed of in a manner that complies with all environmental
regulations. This residual waste stream would be disposed of
either by incineration or by transport to an approved waste
disposal facility.
Numerous vendors for this type of treatment system exist, and EPA
has experienced good success with its use on soils contaminated
with pesticides at other Superfund sites. Treatability studies
would likewise be necessary in order to assess the suitability of
this technology for application at the Helena Chemical Site. The
performance standard for this treatment system would likewise be
the LDRs for site specific contaminants.
The estimated cost for this alternative is $4.4 million.
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8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The alternatives for Site remediation were evaluated based on the
nine criteria set forth in the NCP (40 CFR § 300.430(e)(9)). In
the sections which follow, brief summaries of how the alternatives
were judged against these criteria are presented.
8.1 CRITERIA FOR COMPARATIVE ANALYSIS
8.1.1 Threshold Criteria
Two threshold criteria must be achieved by a remedial alternative
before it can be selected.
1. Overall protection of human health and the environment
addresses whether the alternative will adequately protect human
health and the environment from the risks posed by the Site.
Included in judgement by this criterion is an assessment of how and
whether the risks will be properly eliminated, reduced, or
controlled through treatment, engineering controls, and/or
institutional controls.
2. Compliance with applicable or relevant and appropriate
requirements (ARARs) addresses whether an alternative will meet all
of the requirements of Federal and State environmental laws and
regulations, as well as other laws, and/or justifies a waiver from
an ARAR. The specific ARARs which will govern the selected remedy
are listed and described in Section 9.0, Selected Remedy.
8.1.2 Primary Balancing Criteria
Five criteria were used to weigh the strengths and weaknesses among
alternatives, and to develop the decision to select one of the
alternatives. Assuming satisfaction of the threshold criteria,
these are the main considerations in selecting an alternative as
the remedy.
1. Long term effectiveness and permanence refers to the ability of
the alternative to maintain reliable protection of human health and
the environment over time, once the remediation goals have been
met.
2. Reduction of toxicitv, mobility, or volume addresses the
anticipated performance of the treatment technologies that an
alternative may employ. The 1986 amendment to CERCLA, the
Superfund Amendments and Reauthorization Act (SARA) , directs that,
when possible, EPA should choose a treatment process that
permanently reduces the level of toxicity of site contaminants,
eliminates or reduces their migration away from the site, and/or
reduces their volume on a site.
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3. Short-term effectiveness refers to the length of time needed to
achieve protection, and the potential for adverse effects to human
health or the environment posed by implementation of the remedy,
until the remediation goals are achieved.
4. Implementability considers the technical and administrative
feasibility of an alternative, including the availability of
materials and services necessary for implementation.
5. Cost includes both the capital (investment) costs to implement
an alternative, plus the long-term O&M expenditures applied over a
projected period of operation.
8.1.3 Modifying Criteria
State acceptance and community acceptance are two additional
criteria that are considered in selecting a remedy, once public
comment has been received on the Proposed Plan.
1. State acceptance: The State of South Carolina concurs with
this remedy.
2. Community acceptance was indicated by the verbal'comments
received at the Helena Chemical NPL Site Proposed Plan public
meeting, held on May 27, 1993. The public comment period opened on
May 18, 1993, and closed on June 17, 1993.
Written comments received concerning the Helena Chemical NPL Site,
and those comments expressed at the public meeting, are addressed
in the Responsiveness Summary attached as Appendix A to this ROD.
8.2 COMPARISON OF ALTERNATIVES
All alternatives, except Alternative 1, provide adequate protection
of human health and the environment. All alternatives, again with
the exception of Alternative 1, achieve all identified ARARs. With
respect to short-term effectiveness and implementability,
Alternatives 2-6 are all are comparable. Treatment Alternatives 3
through 6 achieve overall protectiveness and risk reduction by
permanently treating the waste and using the treated materials to
prevent contact with less affected soils beneath the treatment
areas. Landfill Alternative 2 achieves similar risk reductions,
but does not satisfy the statutory preference for reducing the
toxicity and volume of the waste, although the mobility of Site
contaminants would be greatly reduced. Therefore, Alternatives 3-6
are preferable to Alternative 2.
Neither Alternative 3 nor Alternative 4 (biological treatment alone
or HPD alone) has been shown to be fully effective for the entire
range of pesticide contaminants found at the Site. The long-term
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effectiveness of Alternatives 3 and 4 is therefore less assured
than that for Alternatives 5 and 6. Alternative 6, treatment of
soils by LTTD, would make use of a proven treatment technology that
could reasonably be expected to achieve the remedial goals
specified in this ROD. Preliminary studies regarding the proposed
technology described under Alternative 5 (combining biological
treatment with HPD) indicate that remedial goals for all Site
contaminants are likely to be achievable.
Alternatives 5 and 6, therefore, are those that best meet the
statutory preference for permanent solutions that reduce the
toxicity, mobility and volume of waste materials while using
technologies that can reasonably be expected to achieve the
remedial goals determined to be protective of human health and the
environment, and to achieve ARARs. They also fulfill the other
criteria regarding long- and short-term effectiveness and
implementability. The projected cost for Alternative 5 is
significantly less than that for Alternative 6. Given that
Alternative 5 can be implemented at significantly less cost than
could Alternative 6, Alternative 5 is the preferred alternative.
EPA recognizes, however, that the preferred remedy includes a soil
treatment technology (HPD/biological treatment) that is an
innovative technology that has not been demonstrated capable of
achieving performance standards specified in Section 9, below. EPA
therefore will retain Alternative 6 as a contingency remedy to be
implemented should treatability studies of HPD/biological treatment
prove that this technology is incapable of achieving the
performance standards for this Site. The only difference between
Alternative 5 and Alternative 6 is the soil treatment technology to
be employed. Alternative 6 contains low temperature thermal
desorption (LTTD) as the soil treatment technology.
9.0 THE 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 that includes source control,
ground-water remediation, and mitigation for wetlands impacts for
this Site. At the completion of this remedy, the residual risk
associated with this Site will fall within the acceptable range
mandated by CERCLA and the NCP of 10"6 to 10"4 which is determined
to be protective of human health. The unacceptable level of risk
posed to environmental receptors will also be adequately addressed.
The total present worth cost of the selected remedy, Alternative 5,
is estimated at $3.9 million.
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9.1 DESCRIPTION OF SELECTED REMEDY
9:1.1. Source Control
Source control will address the contaminated soils and waste
materials at the Site. Source control shall include excavation of
contaminated soils and waste materials, on-Site treatment by means
of combined hydrolytic/photolytic dechlorination (HPD) and
biological degradation, and placement of the treated soils and
waste materials back into on-Site excavations. The treated soils
will then be covered by a minimum of one foot of clean backfill.
The major components of source control to be implemented include:
9.1.1.1. Excavation
Excavation of materials contaminated with greater than 50 ppm of
total pesticides at the Site. Excavation will be limited to the
uppermost three feet of soils at the Site in order to prevent
creation of a preferential flow path for infiltration of rain water
into the shallow aquifer.
9.1.1.2. Treatment of Excavated Soils
Treatment of all excavated materials by means of a combination of
hydrolytic/photolytic dechlorination and biological degradation.
Contaminated soils and waste materials containing greater than 50
ppm total pesticides from the Site would be treated by means of
hydrolytic/photolytic dechlorination (HPD) of the pesticide
contaminants. This process would be implemented at Helena Chemical
by mixing contaminated soils with chemical reagents and exposing
them to heat and ultraviolet (UV) radiation. The mixing process is
necessary to distribute the reagents (usually hydrated lime,
possibly supplemented by sodium hydroxide) throughout the mass of
contaminated material. The mixed material/reagent mass is then
placed in thin layers in cells similar to those proposed for
biological treatment in order for the soils to be exposed to heat
and UV energy from the sun. The soil mass would also be kept moist
in order to enhance biodegradation of any organic end products
resulting from the hydrolytic/photolytic dechlorination process.
Soils would be periodically 'turned over" to maximize contaminant
exposure to UV radiation.
Contaminated soils containing greater than 50 ppm total pesticides
would also be treated on-site by means of biological degradation
subsequent to the HPD process steps. Biological degradation would
take place in treatment cells constructed on-site that would be
lined to prevent any leaching of contaminants to ground waters
underlying the Site. Treatability studies would be conducted to
determine if this alternative can achieve the remedial goals, but
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preliminary data indicate that significant reductions .in
concentration of many site-specific contaminants can be achieved by
biological degradation. Once soils are treated to the remedial
goals, they would be replaced in the on-site excavations from which
they were removed, and covered by a minimum of one foot of clean
fill. The performance standard for the combined treatment process
would be based upon the LDRs for site-specific contaminants.
Biological treatment cells would consist of lined pits into which
the contaminated soils would be placed. Once placed into the
cells, moisture content, temperature and nutrient levels would be
adjusted and maintained to maximize the rate of biological
activity. Both aerobic and anaerobic conditions are envisioned in
order to maximize the effect of biological degradation.
Anticipated treatment would consist of anaerobic treatment,
particularly for soils contaminated with DDT, followed by aerobic
treatment. Some of the Site soils may require aerobic treatment
alone.
The final element of the source control portion of the .overall
remedy will be to grade the Site and construct any structures or
appurtenances necessary so. that the Site complies with all
regulations regarding storm water run off from industrial
facilities. This will prevent any further non-point source
contribution from future Site activities to contamination in
adjacent waters of the United States.
9.1.2. Ground Water Remediation
Groundwater remediation will address the contaminated groundwater
at the Site. Groundwater remediation will include extraction of
contaminated groundwater, treatment, and discharge to the local
Publicly Owned Treatment Works (POTW).
The major components of groundwater remediation to be implemented
include:
Extraction from the surficial aquifer by means of pumping wells and
treatment by standard treatment technologies generally available to
achieve pre-treatment requirements imposed by the POTW; and
Discharge of treated water to the nearest access point into the
sanitary sewer collection system serving the local POTW.
The installation of ground-water extraction wells will prevent the
migration of contaminants beyond the present extent of the
contaminant plume, and will over time remove contaminants from the
ground water lying beneath the Site. At present, the extent of
contaminated ground water is confined to the shallow aquifer (the
Barnwell Formation) and does not appear to extend to any
significant degree laterally to off-site areas, although one well
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located off the Site property (MW-18) was contaminated during the
RI.
Extracted ground water will be treated to criteria appropriate for
the final means of disposal. At present, it is planned that the
extracted ground water will be treated and discharged to the local
sanitary sewer system, also known as a POTW. Pretreatment
requirements will be set by the owner/operator of that sanitary
sewer system in order to insure that the discharge permit for the
system will not be violated. It is possible, based upon initial
estimates of ground-water quality, that no pretreatment will be
necessary; for the purposes of preliminary cost estimates, however,
it is assumed that some degree of pretreatment for extracted ground
water will be required. The actual technologies to be employed
will be based upon the pretreatment criteria established by the
owner/operator of the POTW.
Extraction of contaminated ground water will continue until the
ground-water remediation goals are met throughout the extent of the
plume. Should it prove to be technically impracticable to achieve
these remedial goals, EPA will amend the ROD to reflect any changes
in remediation criteria.
9.1.3 Wetlands Mitigation
Mitigation for contaminated soils and sediments in the wetland
areas adjacent to the Site and downstream can be accomplished in a
number of ways under the regulations, guidelines and criteria
established under Section 404(b)(1) of the Clean Water Act, which
is an ARAR for the remedial action at this Site. These guidelines
and criteria include the MOA between EPA and the Corps of
Engineers, effective date February 7, 1990, concerning the
determination of mitigation. Removal of the fill placed in the
affected wetlands, accompanied by removal of the contamination that
has resulted from transport of toxic materials from that fill, is
one potential method. Another would be the restoration of degraded
wetlands at some off-site location. Another possibility is the
acquisition of unaffected wetlands that are currently threatened by
development or other destructive activities and placing those
wetland areas in a protected status. A number of factors will be
used to determine the most cost-effective and environmentally sound
manner in which compliance with the mitigation guidelines will be
achieved.
The exact form of mitigation for the effects of contaminated
sediments will be based in part upon the consideration that,
although the sediments are contaminated to a level that is expected
to adversely impact flora and fauna normally found in such a
habitat, and that therefore pose an unacceptable level of risk to
environmental receptors, the habitat function has not been
completely destroyed. In addition, other valuable wetland
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functions remain intact and could conceivably be physically
destroyed by an active removal of contaminated sediments. Physical
reconstruction of wetland areas damaged by such physical
disruptions is theoretically possible, but EPA's experience with
reconstructed wetlands as part of regulatory actions taken under
the authority of Section 404 of the Clean Water Act has been that
limited success can be expected from such projects. Also,
reasonable estimates of the time required to achieve full
restoration of the existing wetlands under this approach may be
similar to that required for natural attenuation and biodegradation
of site-related contamination to insignificant concentrations.
Finally, it is possible that other sources of pesticide
contamination exist that will not be addressed as part of the
remedy for the Helena Chemical Site, since those sources are not
related to the Site or activities that took place at the Site.
Even should a successful reconstruction of contaminated wetlands be
achieved, it is possible that these other sources would rer
contaminate the wetland areas adjacent to the Helena Site,
rendering the reconstruction ineffective in the long term.
Executive Order 11990, and regulations related to that Order found
at 40 CFR Part 6, will also be considered in determining the most
effective means by which the mitigation will be accomplished.
These regulations require EPA to avoid, to the extent possible, the
adverse impacts associated with the destruction or loss of wetlands
and to avoid direct or indirect support of new construction in
wetlands if a practicable alternative exists. Mitigative measures
consistent with these requirements will therefore be given
preference in determining specific actions to be required as part
of the remedial action.
By insuring that adequate habitat for ind Tenous species
potentially found in the wetlands associated with ne Site will be
made available by the mitigative measures proposed, the adverse
impacts to the habitat function of the Helena wetlands can be
remedied. While individuals of these species may under some
mitigative options continue to be impacted by toxic effects of
contaminants in the sediments at the Site, the viability of the
various species populations in the area will be protected and
enhanced by the long-term stability and availability of suitable
habitat provided for by mitigation as part of the remedy.
9.1.4. Compliance Testing
Monitoring of groundwater (both in situ and after extraction and
treatment), excavated soils, and treated soils shall be conducted
as part of this remedial action. After demonstration of compliance
with Performance Standards, Site ground water shall be monitored
for five years. If monitoring indicates that the Performance
Standards set forth below are being exceeded at any time after
pumping has been discontinued, extraction and treatment of the
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ground water will recommence until the Performance Standards are
once again achieved.
Compliance testing of the residual soils that have been subjected
to treatment will also be performed, to insure compliance with the
LDR requirements established as performance standards for- the soil
treatment technology.
9.1.5 Contingency Remedy
Should treatability studies demonstrate that the selected remedy
described above, HPD/biological treatment, cannot achieve
performance standards established for the Site, the treatment
technology used for soil remediation at the Site will be low
temperature thermal desorption (LTTD) in lieu of HPD/biological
treatment. LTTD has been successfully used at other NPL sites with
similar soil contaminants and levels of contamination, and
therefore can be expected to satisfactorily achieve performance
standards at this Site.
Using this technology, contaminated soils exceeding 50 ppm total
pesticides from the Site would be treated on-site by means of low
temperature thermal desorption (LTTD). This process involves
processing contaminated soils through a rotary dryer or kiln. The
soil mass is heated to a temperature level that is sufficient to
drive the contaminants off of the soil matrix, but not high enough
to actually incinerate or destroy the contaminants, Soil
contaminants are volatilized from the solids and purged from the
kiln or dryer by means of an inert purge gas. After the purge gas
leaves the desorption unit, it is treated by an off-gas treatment
system that prevents the soil contaminants from being released into
the environment. Typical air pollution control equipment (such as
cyclonic precipitators and baghouses) are also used to protect air
quality during operation of desorption units.
Numerous vendors for this type of treatment system exist, and EPA
has experienced good success with its use on soils contaminated
with pesticides at other Superfund sites. Treatability studies
would likewise be necessary in order to assess the suitability of
this technology for application at the Helena Chemical Site. The
performance standard for this treatment system would likewise be
the LDRs for site specific contaminants.
9.2. APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARs)
9.2.1. Applicable Recruirements
The remedy will comply with all applicable portions' of the
following Federal and State regulations:
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40 CFR Part 6, Subpart C, promulgated under the authority of the
National Environmental Policy Act. Specifically:
Section 6.302(a), governing protection of wetlands, including
referenced Appendix A to 40 CFR Part 6. These regulations
incorporate Federal Executive Order 11990 into Federal
regulation.
40 CFR Part 122, promulgated under the authority of the Clean Water
Act. Specifically:
Section 122.26, governing storm water discharges from
industrial sites.
Section 122.50, governing discharges to publicly owned
treatment works (POTWs).
40 Part 136, promulgated under the authority of the Clean Water
Act. These regulations govern the water quality testing of
discharges associated with NPDES-related activities. For this Site
they are applicable to testing of waters discharged to a POTW and
to the testing of storm water discharges.
South Carolina Code of Regulations (SCCR) Chapter 61-72, governing
the discharge of storm waters from industrial sites. Specifically:
Section 72.307, containing design criteria for storm water
discharge facilities.
SCCR Chapter 61-69, governing ambient water quality standards for
surface and ground waters. Specifically:
Section 61-68(C), establishing applicability of state water
quality standards.
Section 61-68(E), establishing minimum criteria for all state
waters.
Section 61-68(F), establishing ambient standards for surface
waters.
Section 61-68(G), establishing ambient standards for ground
waters.
9.2.2. Relevant and Appropriate Requirements
40 CFR Part 141, promulgated under the authority of the Safe
Drinking Water Act. Specifically:
Maximum Contaminant Levels (MCLs) and Maximum Contaminant
Level Goals (MCLGs) promulgated under the authority of the
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Safe Drinking Water Act are specifically identified in the
National Contingency Plan (NCP) as remedial action objectives
for ground waters that are current or potential sources of
drinking water supply. The ground waters underlying this Site
are classified as Class IIA ground waters under the EPA
Guidelines for Ground-Water Classification. Ground-water
extraction and treatment is included in this remedy in order
to satisfy EPA's stated goal of returning usable ground waters
to their beneficial uses within a reasonable time frame (see
FRVol. 53, no. 245, p 51433, and Section 300 .430 (a) (1) (ii) (F)
of the NCP) . MCLs and MCLGs are therefore relative and
appropriate for use as remedial action objectives for the
remedial action at this Site.
Maximum Contaminant Level Goals (MCLGs) are found in 40 CFR
Part 141, Subpart F.
Maximum Contaminant Levels (MCLs) are found in 40 CFR Part
141, Subparts B and G.
40 CFR Part 230, Subparts B and H, promulgated under the authority
of the Clean Water Act. These regulations govern the mitigation of
impacts to jurisdictional wetlands associated with the placement of
fill material in waters of the United States and any secondary
adverse impacts resulting from that placement.
Since the solid waste on-Site is not hazardous waste, but contains
hazardous constituents, the following regulations established under
the authority of RCRA are relevant and appropriate to the
circumstances of the release, but are not directly applicable.
This includes regulations found at 40 CFR Parts 261-268 cited
below.
40 CFR Part 261, Subpart B. These regulations establish methods
for the testing of hazardous materials at RCRA-regulated
facilities. They will be used to guide testing procedures
established as part of the compliance monitoring portion of this
remedy.
40 CFR Part 264, Subpart B, established under the authority of
RCRA. Specifically:
Section 264.14, establishing criteria for Site security.
Section 264.15, establishing criteria for inspection of the
Site by the owner/operator.
Section 264.16, establishing criteria for training of
personnel who will be involved in Site remediation.
40 CFR Part 264, Subpart D, which requires the development of a
contingency and emergency procedures plan for the Site.
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40 CFR Part 264, Subpart F, which governs releases from solid waste
management units. Specifically:
Section 264.95, which requires the establishment of a point of
compliance for ground-water protection standards. The
performance standards established in this ROD for ground-water
remediation will serve as the ground-water protection
standards. A point of compliance will be established at the
downgradient boundary of the final disposal site for treated
soils and waste materials.
Section 264.97, which establishes requirements for a ground-
water monitoring program. These requirements will be used to
establish a ground-water monitoring program for the purpose of
evaluating releases from the final disposal site for treated
soils and waste materials.
Section 264.98, which established requirements for a detection
monitoring program. This detection monitoring program will be
used to evaluate potential releases from the final disposal
site for treated soils and waste materials.
40 CFR Part 264, Subpart G, which governs closure of solid waste
management units. Specifically:
Section 264.111, which sets forth closure performance
standards.
Section 264.112, which requires the submission of a closure
plan for review and approval.
40 CFR Part 268, Subpart D, which establishes treatment standards
which must be achieved prior to land disposal of hazardous wastes.
These regulations will establish the performance standards for
treatment of contaminated soil and waste materials excavated from
the Site.
Federal Ambient Water Quality Criteria (AWQC) established under the
authority of Section 304(a) of the Clean Water Act.
These criteria are specifically identified in Section
121 (d) (2) (A) of CERCLA as amended by SARA to be ARARs for
CERCLA remedial actions. AWQC are developed as guidance for
the States to develop ambient surface water quality standards
that will be fully protective of human health and the
environment. As such, AWQC are relevant and appropriate to
the selected remedial action. Discharge of the treated
effluent from this site must not result in ambient surface
water concentrations that exceed chemical-specific AWQC.
SCCR Chapter 61-79, which contain the State of South Carolina
regulations governing the management, treatment, storage and
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disposal of hazardous wastes. These regulations are, in a manner
analogous to Federal RCRA regulations, relevant and appropriate to
the circumstances of the releases from this Site without being
directly applicable. In addition, since the South Carolina
regulations simply incorporate verbatim the Federal RCRA
regulations, the sections of SCCR Chapter 61-79 corresponding to
the Federal RCRA sections cited above are hereby incorporated into
this ROD as relevant and appropriate requirements.
9.2.3 Criteria "To Be Considered"
CERCLA guidance recommends the identification of criteria that may
be relevant and appropriate to the circumstances of the release at
a site, but which do not meet the statutory definition of an ARAR.
To be defined as an ARAR, a standard or criterion must be a
requirement or regulation promulgated under Federal or state
authority, and must be of general applicability. Other standards
or criteria, known as criteria to be considered or TBCs, may be
necessary in order for the remedy to be fully protective of human
health and the environment. These TBCs may include EPA reference
doses, cancer potency factors, drinking water health advisories or
other health-based criteria.
A number of TBC criteria have been identified for ground-water
remediation at the Helena Chemical NPL Site. They are based upon
protection of human health via drinking water exposure, using data
contained in EPA data bases regarding toxicity and/or
carcinogenicity of these compounds, and also using standard
assumptions regarding intake and exposure via drinking water.
The following TBC criteria have been developed based upon an
incremental carcinogenic risk of 1 X 10"6:
Aldrin 0.002 parts per billion (ppb)
alpha-BHC 0.006 ppb
beta-BHC 0.020 ppb
delta-BHC 0.006 ppb
Dieldrin 0.002 ppb
DDT 0.100 ppb
ODD 0.100 ppb
DDE 0.100 ppb
The following TBC criteria are based upon non-carcinogenic toxicity
(hazard index less than 1):
Disulfoton 1.400 ppb
Endrin Ketone 2.000 ppb
Lead 15.000 ppb
In addition, the Memorandum of Agreement between EPA and the U.S.
Army Corps of Engineers concerning the determination of mitigation
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under the Clean Water Act Section 404(b)(l) guidelines ia also a
TBC criterion for remedial actions related to wetlands mitigation
at this Site.
9.3. PERFORMANCE STANDARDS
The Performance Stan.dards for this component of the selected remedy
include the following:
9.3.1. Excavation Standards
Excavation shall continue until the remaining soil and materials
are contaminated at a concentration of no more than 50 parts per
million (ppm) total pesticides. Total pesticides shall be
determined by summing the concentrations of all pesticides found in
any soil sample analyzed for the pesticides fraction of the
Hazardous Substances List (HSL). Testing methods approved by EPA
shall be used to determine if the allowable pesticide concentration
levels have been achieved.
9.3.2. Treatment Standards
Since the remedy also specifies land disposal of the treated waste,
the LDR-based ARARs are also performance standards for the residue
left after treatment of the soils and waste. These performance
standards are found in 40 CFR Part 268, Subpart D, Section 268.43.
They are:
From Table CCW1:
Aldrin 66 parts per billion (ppb)
BHC, all isomers, total 660 ppb
Chlordane, total 130 ppb
Dieldrin 130 ppb
Disulfoton 100 ppb
DDT, DDE, DDD, total 87 ppb
Endrin 130 ppb
Endosulfan, all isomers, total 66 ppb
Endosulfan sulfate 130 ppb
Heptachlor 66 ppb
Heptachlor epoxide 66 ppb
Methoxychlor 180 ppb
Toxaphene 1300 ppb
Note 1: Compliance to be determined by grab samples of
treatment residue.
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81
9.3.3. Ground-Water Remediation Standards
Groundwater shall be extracted until the following Maximum
Concentration Levels (MCLs) are attained at the wells designated
during remedial design by EPA as compliance points.
Aldrin 0.002 parts per billion (ppb)
Benzene 5.0 ppb
alpha-BHC 0.006 ppb
beta-BHC 0.02 ppb
delta-BHC 0.006 ppb
Chlordane 2.0 ppb
Chromium 100.0 ppb
Dieldrin 0.002 ppb
DDT 0.1 ppb
ODD 0.I ppb
DDE 0.1 ppb
Endrin 2.0 ppb
Lead 15.0 ppb
Lindane 0.2 ppb
Toxaphene 3.0 ppb
Heptachlor 0.4 ppb
9.3.4 Storm Water Discharges
Final Site grading and drainage shall comply with the substantive
design criteria contained in SCCR Chapter 61-72, Section 72.307.
9.3.5 Wetlands Mitigation
Wetlands mitigation actions taken as part of this remedy shall
comply with the substantive requirements of 40 CFR Part 230,
Subparts B and H, promulgated under . the authority of the Clean
Water Act. These regulations govern the mitigation of impacts to
jurisdictional wetlands associated with the placement of fill
material in waters of the United States and any secondary adverse
impacts resulting from that placement. Quantitative performance
standards shall be established as part of remedial design
activities.
Mitigation activities shall also comply with the requirements of 40
CFR Part 6, Subpart C, promulgated under the authority of the
National Environmental Policy Act. Specifically:
Section 6.302(a), governing protection of wetlands, including
referenced Appendix A to 40 CFR Part 6. These regulations
incorporate Federal Executive Order 11990 into Federal
regulation.
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82
10.0 STATUTORY DETERMINATIONS
The selected remedy for this Site meets the statutory requirements
set forth at Section 121(b)(l) of CERCLA, 42 U.S.C. § 9621(b)(l).
This section states that the remedy must protect human health and
the environment; meet ARARs (unless waived); be cost-effective; use
permanent solutions, and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable;
and finally, wherever feasible, employ treatment to reduce the
toxicity, mobility or volume of the contaminants. The
following sections discuss how the remedy fulfills these
requirements.
Protection of human health and the environment: The selected soil
remedy will remove the human health risks from dermal contact and
incidental ingestion of contaminated Site soils. The groundwater
remediation system will extract and treat contaminated groundwater,
thereby reducing and eventually removing the future risks to human
health which could result from ingestion of or contact with
groundwater, and the environmental risks which could result from
continued discharge of contaminants to adjacent jurisdictional
waters.
In addition, the remedy selected to address the contamination of
surface waters and sediments in the on-Site and adjacent wetlands
(mitigation as per CWA Section 404 guidelines) will be protective
of the environment.
Compliance with ARARs: The selected remedy will meet ARARs, which
are listed in Section 9.2 of this ROD.
Cost effectiveness: The selected soil remedy component is the most
cost effective of the alternatives considered. Among the
alternatives that are protective of human health and the
environment and comply with all ARARs, the selected alternative is
the most cost-effective choice because it uses a treatment method
for which costs can be reliably predicted and because the use of
the POTW option is the most cost-effective means to dispose of the
treated groundwater.
Utilization of permanent solutions, and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable: The selected remedy represents the maximum
extent to which permanent solutions and treatment can practicably
be used for this action. All of the selected remedy components are
considered permanent solutions.
Among the alternatives that are protective of human health and the
environment and comply with all ARARs, EPA and the State of South
Carolina have determined that the selected remedy achieves the best
balance of trade-offs in terms of long-term effectiveness and
permanence, reduction of toxicity/mobility/volume, short-term
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83
effectiveness, implementability, and cost. Hie selected
groundwater action is more readily implementable than the other
alternatives considered, and utilizes the most cost-effective
option for disposal of treated water. The selected soil remedial
action achieves the best compliance with the five balancing
criteria described in the NCP.
Preference for
The
proposed groundwater remediation system will fulfill the preference
for treatment as a principal element, through extraction and
treatment of contaminated groundwater until the remedial goals are
achieved.
The soil remedial action will also satisfy the preference, due to
the treatment of soils by the selected technology,
HPD/biodegradation. Likewise, the contingency remedy fully
satisfies this preference.
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PB94-964070
EPA/ROD/R04-93/144
February 1995
EPA Superfund
Record of Decision:
Hercules 009 Landfill Site,
(O.U. 1) Brunswick, GA
3/25/1993
Information Resource Center
US EPA Region 3
Philadelphia, PA 19107
EPA Report Collection
Information Resource Center
US EPA Region 3
Philadelphia, PA 19107
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R04-93/144
3. Recipient's Accession No.
4. Title and Subtitle
SUPERFUND RECORD OF DECISION
Hercules 009 Landfill, GA
Second Remedial Action - Final
5. Rsport Date
03/25/93
6.
7. Author(s)
8. Performing Organization Rept. No.
9. Performing Organization Nam* and Address
10 Project Task/Work Unit No.
11. Contraet(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Nam* and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/800
14.
15. Supplementary Notes
PB94-964070
16. Abstract (Limit: 200 words)
The 16.5-acre Hercules 009 Landfill site is an inactive industrial landfill located in
Brunswick, Glynn County, Georgia. Land use in the area is predominantly commercial and
residential, with a shopping mall, bank, and restaurant located approximately 1,000
feet north of the site. From 1948 to 1980, Hercules manufactured toxaphene, an
agricultural pesticide used to control boll weevils, ticks, and mites on cattle. Under
a State permit, Hercules used seven acres at the northern end of the site, known as the
009 landfill, to dispose of approximately 33,000 yd3 of wastewater sludge from the
production of toxaphene, empty toxaphene product drums, and toxaphene-contaminated
glassware, rubble, and trash. The landfill was constructed as six cells, which
reportedly were lined with a soil bentonite clay mixture across the bottom and along
the bermed walls. The thickness of the toxaphene sludge disposed of in these cells was
reported to be six to seven feet. Typically, the wastewater sludge was disposed of
directly in the landfill; however, occasionally it was staged near the southeast corner
of the landfill prior to disposal. In 1980, as a result of a State investigation which
revealed toxaphene in soil and water samples from the drainage ditches.around the site,
Hercules' permit was canceled, and the State ordered the landfill to be closed. In
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Hercules 009 Landfill, GA
Second Remedial Action - Final
Contaminated Media: soil, sludge, gw, sw
Key Contaminants: VOCs (benzene, TCE, toluene, xylenes), other organics (dioxin,
pesticides), metals (arsenic, chromium, lead)
b. Identifiers/Open-Ended Terms
c. COSATI Field/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None •
21. No. of Pages
72
22. Price
(SeeANSI-Z39.18)
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R04-93/144
Hercules 009 Landfill, GA
Second Remedial Action - Final
Abstract (Continued)
1982, EPA banned the use of toxaphene and site operations ceased. A 1991 ROD addressed an
interim action for ground water by extending the existing municipal water lines, as OU2.
This ROD provides a final remedy for the site and addresses contaminated soil, debris,
sludge, ground water, and surface water, as OU1. The primary contaminants of concern
affecting the soil, sludge, ground water, and surface water are VOCs, including benzene,
TCE, toluene, and xylenes; other organics, including dioxin and pesticides; and metals,
including arsenic, chromium, and lead.
The selected remedial action for this site includes conducting a field-scale treatability
study; excavating and transporting the subsurface soil, sludge, and related material in
the staging area with levels exceeding 76 mg/kg of toxaphene, and the surface soil in the
staging area with levels exceeding 0.25 mg/kg of toxaphene to the landfill area; treating
the consolidated surface soil, subsurface soil, and sludge using in-situ stabilization as
an innovative application to treat organics; covering treated soil and sludge using a clay
multi-media cover; backfilling excavated areas with two feet of clean native fill;
providing for a contingency remedy to treat the soil and sludge by dewatering the soil and
sludge, onsite ex-situ chemical extraction, with onsite disposal of the treated material,
based on the results of a treatability study; monitoring ground water, surface water,
sediment, and air; providing for a contingency remedy to extract and treat contaminated
ground water onsite using granular activated carbon or another treatment, followed by
onsite or offsife discharge to a POTW, and offsite disposal of the spent granular
activated carbon, if toxaphene or other chemicals are shown to be migrating offsite or
from their current positions, or contaminants of concern begin to increase over 50% of
their current value, or it does not seem feasible that the ground~water will naturally
attenuate over time; operating and maintaining the cover for a minimum of 30 years and
possibly abandoning onsite private wells; and implementing institutional controls,
including deed restrictions. . The estimated present worth cost for this remedial action i'
$9/900,000, which includes an estimated annual O&M cost of $104,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil excavation goals are based on attaining the baseline risk equal to
or less than 1x10"^ for toxaphene, and include surface soil 0.25 mg/kg and subsurface soil
76 mg/kg. Chemical-specific surface soil goals are based on the risk assessment of 1x10"^
for future land:use, and include alpha-BHC 0.044 mg/kg; arsenic 5 mg/kg; acetone 360
mg/kg; benzene 10 mg/kg; beryllium 0.15 mg/kg; bis (2-ethylhexyl) phthalate 20 mg/kg;
cadmium 41 mg/kg; carbon tetrachloride 2.1 mg/kg; chlorobenzene 720 mg/kg; chloroform 45
mg/kg; chromium (III) 56 mg/kg; copper 3,300 mg/kg; dioxin/furans (TEF) 0.001 mg/kg;
Endosulfan II 1.8 mg/kg; ethylbenzene 3,600 mg/kg; lead 500 mg/kg; manganese 4,900 mg/kg;
mercury 26 mg/kg; methylene chloride 37 mg/kg; nickel 310 mg/kg; toluene 7,200 mg/kg; TCE
25 mg/kg; toxaphene 0.25 mg/kg; vanadium 600 mg/kg; xylenes 70,000 mg/kg; and zinc 17,000
mg/kg. Chemical-specific subsurface soil goals are based on the risk assessment of IxlO"6
for future land use, and include acetone 1 mg/kg; alpha-BHC 0.01 mg/kg; arsenic 3,400
mg/kg; benzene 0.06 mg/kg; beryllium 61 mg/kg; bis (2-Ethylhexyl) phthalate 46 mg/kg;
cadmium 11,000 mg/kg; carbon tetrachloride 0.07 mg/kg; chlorobenzene 1.7 mg/kg; chloroform
0.4 mg/kg; chromium (III) 1,000,000 mg/kg; copper 420,000 mg/kg; dioxin/furans (TEF) 0.14
mg/kg; Endosulfan II 0.29 mg/kg; ethylbenzene 13 mg/kg; lead 500 mg/kg; manganese
1,000,000 mg/kg; mercury 3,400 mg/kg; methylene chloride 0.03 mg/kg; nickel 220,000 mg/kg;
TCE 0.08 mg/kg; toluene 30 mg/kg; toxaphene 76 mg/kg; vanadium 79,000 mg/kg; xylenes 80
mg/kg; and zinc 1,000,000 mg/kg. Chemical-specific ground water goals for natural
attenuation are based on SDWA MCLs, and include benzene 0.005 mg/1; cadmium 0.005 mg/1;
chromium 0.1 mg/1; manganese 0.05 mg/1; nickel 0.1 mg/1; toluene 1 mg/1; toxaphene 0.003
mg/1; and xylenes 10 mg/1.
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RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
HERCULES 009 LANDFILL SITE
OPERABLE UNIT ONE
BRUNSWICK, GLYNN COUNTY, GEORGIA
PREPARED BY
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
ATLANTA, GEORGIA
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DECLARATION
of the
RECORD OF DECISION
OPERABLE UNIT ONE
SITE NAME AND LOCATION
Hercules 009 Landfill Site
Brunswick, Glynn County, Georgia
STATEMENT OF BASIS AND PURPOSE
This decision document (Record of Decision), presents the selected
remedial action for Operable Unit One for the Hercules 009 Landfill
Site, Brunswick, Georgia, developed in accordance with the
Comprehensive Environmental Response, Compensation and Liability Act
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 Hercules
009 Landfill site ("the Site").
The State of Georgia has concurred with the selected-remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the
Hercules site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare or the environment.
DESCRIPTION OF SELECTED REMEDY
This operable unit is one of two for this Site. This alternative
calls for the design and implementation of response measures which
will protect human health and the environment. Operable unit one,
which is enumerated by this Record of Decision, addresses the source
areas, surface water, and groundwater at the Site. Operable unit two
was enumerated in an Interim Action ROD that was signed by EPA on June
27, 1991. Operable unit two addressed the off-site threat of future
groundwater contamination by extending the existing municipal water
lines in the City of Brunswick, Georgia to residents that live
adjacent to this Site.
The major components of the selected remedy for operable unit one
include:
• Conducting a field-scale treatability study and implementation of
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in-situ stabilization of subsurface soils and consolidated surface
soils. This remedy is an innovative application of this
technology since EPA has minimal information on stabilization of
manufactured pesticides;
• Implementation of an ex-situ chemical extraction technology on the
soils and sludges at the Site (with onsite disposal of the treated
material) in the event the treatability study concerning the
stabilization of Site soils and sludges fails to met the required
standards and therefore will not be effective if implemented;
• Construction of a cover over the treated soils to reduce rainwater
infiltration and direct contact with the treated soil. In
addition, areas excavated for consolidation of surface soil would
be graded and covered with two feet of clean, compacted, native
fill;
• Long-term monitoring of groundwater, as well as- surface water and
sediment in the onsite pond and the adjacent drainage.ditch, with
the contingency implementation of a pump and treat system in case
any of the following occurs: toxaphene begins to migrate off the
Hercules property; if the other contaminants of concern are shown
to be migrating from their current positions; if any levels of the
contaminants of concern begin to increase over fifty percent of
their current value; or in case it becomes apparent that onsite
levels of contaminants in the groundwater will not naturally
attenuate below MCLs over time;
• Operation and maintenance of the cover for a minimum of thirty
years; and
• Institutional controls for land use and groundwater use
restrictions.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment,
complies with federal and state requirements that are legally
applicable or relevant and appropriate to the remedial action, and is
cost-effective. This remedy satisfies the preference for treatment
that reduces toxicity, mobility, or volume as a principal element.
Finally, it is determined that this remedy utilizes a permanent
solution and alternative treatment technology to the maximum extent
practicable.
Because this remedy will result in hazardous substances remaining
onsite above health-based levels, a review will be conducted within
five years after commencement of the remedial action to ensure that
the remedy continues to provide adequate protection of human health
and the environment.
PATRICK M. TOBIN, ACTING REGIONAL ADMINISTRATOR DATE
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TABLE OF CONTENTS
1.0 Site Location and Description 1
2 .0 Site History and Enforcement Activities 1
3 .0 Highlights of Community Participation 4
4.0 Scope and Role of Operable Units 5
5 .0 Summary of Site Characteristics 5
5.1 Geology/Soils ._ 5
5 .2 Hydrology 7
5.3 Surface Water and Sediments 8
5 .4 Air Monitoring 9
6 .0 Summary of Site Risk 9
6 .1 Contaminants of Concern 9
6.2 Exposure Assessment 9
6 .3 Toxicity Assessment ~ 15
6.4 Risk Characterization 15
6.5 Environmental Risk 16
6.6 Cleanup Goals 18
7.0 Description of Alternatives 20
7.1 Alternative No. 1 - No-Action 24
7.2 Alternative No. 2 - Pump and Treat 24
7.3 Alternative No. 3 - RCRA Cap 7". 25
7.4 Alternative No. 4 - In-Situ Stabilization 26
7.5 Alternative No. 5 - Chemical Extraction , 28
8.0 Summary of the Comparative Analysis of Alternatives. 29
8.1 Overall Protection of Human Health and the Environment...33
8.2 Compliance With ARARS 34
8.3 Long-Term Effectiveness and Permanence 40
8.4 Reduction of Toxicity, Mobility or Volume By Treatment...43
8.5 Short-Term Effectiveness 43
8 . 6 Implementability 45
8 .7 Cost 48
8.8 State Acceptance 49
8 . 9 Community Acceptance 50
9.0 Summary of Selected Remedy 50
10.0 Statutory Determination - 58
10.1 Protective of Human Health and the Environment 59
10.2 Attainment of ARARs 59
10.3 Cost Effectiveness 61
10.4 Utilization of Permanent Solutions 61
10.5 Preference for Treatment as a Principal Element 61
11.0 Documentation of Significant Changes 62
Appendix A - Responsiveness Summary 63
Appendix B - Concurrence Letter 97
-i-
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LIST OF TABLES
Table 6-1
Table 6-2
Table 6-3
Table 6-4
Table 6-5
Table 8-1
Table.8-2
Table 8-3
Table 8-4
Table 8-5
Chemicals of Concern - Sludge and Soil 10
Chemicals of Concern - Groundwater 12
Summary of Cumulative Potential Cancer Risk and Non-
Carcinogenic Hazard Indices 17
Remedial Action Target Concentrations._. 22
Estimated Volumes of Affected Materials 23
Comparative Analysis of Alternatives 31
Potential Location-Specific ARARs .36
Potential Action-Specific ARARs for Selected Remedy 37
Potential Action-Specific ARARs for Contingent Remedies..38
Comparison of Costs 49
-11-
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LIST OF FIGURES
Figure 1-1 Area Map for Brunswick, Georgia 2
Figure 1-2 Site Map for the Hercules 009 Landfill Site 3
Figure 5-1 Cross-Section of a Typical Landfill Cell at the Site 7
Figure 6-1 Map of Monitoring Well Locations ~ 21
Figure 9-1. Map Showing Locations of Major Areas to be Stabilized...54
-111-
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Decision Summary
Record of Decision
Operable Unit One
Hercules 009 Landfill Site
Brunswick, Georgia
1.0 SITE LOCATION AND DESCRIPTION
The Site is located in the eastern portion of Glynn County, Georgia,
approximately two miles south of Interstate 95 and one-half mile north
of the City of Brunswick as shown on Figure 1-1. Figure 1-2 is a map
of the Site. The Site is a .16.5 acre property that is bordered by
Georgia State Highway 25 (Spur 25) on the west; an "automobile
dealership on the north; a juvenile slash pine forest on the east; and
several homes, a church, a school, and a strip shopping center to the
south/southeast of the property. A shopping mall, built in 1985, a
bank, and a restaurant are located approximately 1,000 feet north of
the landfill. The property is fenced and has only one entrance
through a locked gate.
Seven acres on the north end of the property were operated as an
industrial landfill by Hercules between 1976 and 1980 under'a permit
by the Georgia Environmental Protection Division (GaEPD). The permit
allowed for the disposal of wastewater sludge generated from the
production of toxaphene at the Hercules Brunswick Plant. Six disposal
cells were constructed at the northern end of the property to receive
sludge for disposal. During its years of operation, the 009 Landfill
was monitored by the GaEPD.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
Hercules began manufacturing toxaphene, an agricultural pesticide, in
1948 and continued production through 1980. Toxaphene received
widespread use in the southeastern United States to control boll
weevils as well as mites and ticks on cattle, until EPA banned its use
in 1982 . The Site had been used by the State as a borrow pit for soil
during the construction of Spur 25. Hercules was issued a permit in
1975 by the GaEPD to use seven acres at the northern end of the
property as a landfill to dispose of wastewater sludge generated
during the manufacturing processes.
The 009 Landfill was constructed at the northern end of the property
as six cells, each approximately 100 to 200 feet wide (north-south
direction) and 400 feet long (west-east direction). The thickness of
the toxaphene sludge in the cells was reported to be six to seven
feet. Individual cells were reported to be lined with a
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Figure 1-1
Area Map for Brunswick, Georgia
soil/bentonite clay mixture across the bottom of the cell and along
the bermed walls.
The sludge deposited in the 009 Landfill consisted of very fine
calcareous particulate, diatomaceous earths and finely crushed
limestone material. Toxaphene adsorbed to this material during
neutralization of by-product hydrochloric acid. Reportedly, the
wastewater treatment sludge consisted of about one percent toxaphene
by weight and 50 percent solids by weight. The sludge was transported
to the landfill in bulk by truck. Trucks hauling material to the Site
reportedly entered the landfill through two entrances, one from
Benedict Road (south side), the other located along Spur 25 (west
side). Typically'the sludge was placed directly into the landfill.
However, sludge was occasionally staged near the southeastern corner
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Figure 1-2
Site Map for the Hercules 009
Landfill Site
of the 009 Landfill prior to placement
In addition to the sludge, the 009 Landfill was also used for disposal
of empty toxaphene product drums, and toxaphene contaminated
glassware, rubble, and trash. Disposal of this material was primarily
limited to Cell 1. Hercules estimated that approximately 33,000 cubic
yards of sludge had been disposed of in the landfill. The cells were
covered with a 24 to 30 inches of "stump dirt" mixed with boiler ash.
The term "stump dirt" refers to soil that was entrained on pine stumps
purchased by the Hercules Brunswick Plant for the extraction of resins
and essential oils.
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All cells in the landfill were closed prior to 1983 in accordance with
existing GaEPD Solid Waste Management Regulations. The final contour
of the top of the landfill has a slope of approximately one percent to
prevent pooling and to minimize infiltration of precipitation. The
sides of the unit have a slope of about ten percent. To control
erosion, the earthen cover was seeded with grasses that have proven to
grow well in the Brunswick area.
A drainage ditch is located adjacent to the landfill at the eastern
edge. To control surface runoff from the surrounding area, Glynn
County periodically excavates the sediments from this ditch to ensure
adequate drainage capacity. Prior to 1988, sediments from the ditch
were stockpiled on the eastern bank of the ditch, but in early 1988,
these sediments were removed.
During its operation, the landfill was inspected by GaEPD. In March
1980, GaEPD collected soil and water samples from drainage ditches
around the Site. The samples contained toxaphene. As a result, GaEPD
canceled Hercules' permit and the 009 Landfill was closed under a plan
approved by GaEPD.
EPA calculated a Hazard Ranking Score for the closed landfill. In
1984, the landfill was placed on the National Priority List (NPL). As
of July 1, 1991, the Hercules 009 Landfill Site ranked 152 out of 1072
on the NPL (excluding federal facilities). GaEPD began negotiations
with Hercules to perform an RI/FS and initiated Site investigation
activities under State Superfund authority, then withdrew as lead
agency in 1987. EPA assumed primary control of the Site investigation
and related activities at the end of 1987. Hercules and EPA entered
into an Administrative Order on Consent in July 1988. The Consent
Order required Hercules to perform a Remedial Investigation
/Feasibility Study (RI/FS) of the Site.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The main branch of the Brunswick-Glynn Regional Library at 208
Gloucester Street in Brunswick, Georgia was chosen as the local
information repository for the Site. A public comment period for the
proposed plan for operable unit #2 (concerning extension of the
municipal water lines) was held from May 13, 1991 to June 12, 1991
with a public meeting being held on May 15, 1991.
The public comment period on the proposed plan preceding this ROD
(operable unit #1) was held August 27, 1992 through October 27, 1992.
A public meeting was held on Thursday, September 10, 1992 where
representatives from EPA answered questions from approximately 150
people regarding the Site and the proposed plan under consideration.
The administrative record was available to the public at both the
information repository maintained at the Brunswick-Glynn Regional
Library and at the EPA Region IV Library at 345 Courtland Street in
Atlanta, Georgia. The notice of availability of these documents was
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published in the Brunswick News-Herald on August 24, and September 4,
1992. EPA received numerous oral and written comments during the
comment period. Responses to the significant comments received are
included in the Responsiveness Summary, which is part of this ROD and
designated Appendix A.
This decision document presents the selected remedial action for
operable unit one of the Hercules site, chosen in accordance with
CERCLA, as amended by SARA and to the extent practicable, the NCP.
The decision for this Site is based on the administrative record. 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 UNITS
EPA has organized the work at this Superfund Site into two operable
units (OUs). These units are:
• OU one: The source area at the Site, including the landfilled
sludge, the soils in the sludge-staging area, and the
Benedict Road/Nix Lane area. Contamination in the
groundwater, surface water, sediment, and soils are
addressed in OU #1. Proper abandonment of the private
wells replaced during OU #2 is included in OU #1 if the
owners will allow abandonment.
• OU two: The extension of municipal water lines to residents
adjacent to the Site was specified in OU #2 to address
the threat of a groundwater plume that could affect
residential drinking wells downgradient of the Site.
OU #1 addresses both the source of contamination in the soils as well
as the groundwater contamination underneath the Site. The purpose of
this operable unit is to monitor groundwater restoration, treat the
source areas at the Site, prevent current or future exposure to the
contaminated soils and groundwater, and reduce contaminant migration.
OU #1 will be consistent with the actions taken during OU #2, to the
extent practicable. The Record of Decision (ROD) governing OU #2
dated June 27, 1991 erroneously was titled OU #1. However, the ROD
dated June 27, 1991 documents the remedial action selection for OU #2.
This ROD documents the remedial action selection for OU #1.
5.0 SUMMARY OF SITE CHARACTERISTICS
5.1 GEOLOGY/SOILS
The results of the RI led to the following findings and conclusions:
• The Site lies in the Atlantic Coastal Plain province of Georgia.
Surface sediments are described as relatively thin layers of
sands, gravels, and clays of Pleistocene age. These sedi.uents,
generally less than 150 feet thick, represent the surficial layer.
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Beneath the surficial layer are Miocene sediments which are
represented by the Hawthorn formation. The Hawthorne contains
several clay units and is a confining zone between the surficial
water-bearing unit and the deeper Floridan aquifer. The Floridan
aquifer, at an approximate depth of 500 feet, is separated from
the surficial water-bearing unit by approximately 400 feet of the
Miocene sediments. The Floridan aquifer is the primary aquifer in
the area for large irrigation and municipal supplies, while
shallower wells are used for small domestic supplies.
Soils at the Site consist of coarse to clayey sands, sandy silts,
and sandy to silty clays. The soils can be grouped into three
distinct hydrogeologic components. From land surface to depths of
25 to 45 feet below land surface is a zone compo'sed of silty sands
and sandy silts. Underlying this zone is a clayey sand and sandy
clay interval ranging in thickness from 10 to 25 feet. The clayey
interval may possibly act as a semi-confining unit within the
surficial layer dividing the silts and sands into shallow and deep
zones beneath the Site; however, the continuity of this unit to
the west side of the landfill is not completely defined due to
limited drilling on the upgradient (west) side of the landfill.
The material that immediately underlies the clayey zone,
representing the third unit, is composed of sands and silty sand
to approximately 85 feet below land surface, where a change to a
coarse sand containing gravel is noted.
Site-specific permeability values ranged from 4xlO"5 centimeters
per second to 9xlO"5 centimeters per second and correspond to the
shallow zone of the surficial water-bearing unit.
Toxaphene concentrations in the soils surrounding the landfilled
sludge ranged from below the detection limit to 4,900 ppm.
Concentrations of toxaphene were generally highest in the vicinity
of the landfill cells and decreased with distance from the cells.
An exception was an area near the Benedict Road/Nix Lane entrance
to the. Site. Toxaphene concentrations of 26 ppm to 92 ppm in this
area may be the result of sludge transportation to the landfill.
Toxaphene was detected in landfilled sludge samples at
concentrations ranging from 850 to 15,000 ppm. The average sludge
concentration of toxaphene is 6,000 ppm.
Acetone, carbon tetrachloride, chlorobenzene, chloroform, and
xylenes were detected in the landfilled sludge samples, but were
not consistently present. No volatile organic constituents (VOCs)
were detected in samples from cells 3, 4, and 6. One or more VOCs
was detected in samples from cells 1, 2, and 5.
Arsenic, chromium, copper, lead, manganese, nickel, vanadium, and
zinc were detected in sludge samples. Of these metals, only
copper and lead exceeded typical background concentration ranges.
Dioxins and furans were detected in all of the sludge samples.
-------
When evaluated based on the Toxicity Equivalence Factor (TEF), by
which the concentrations of all isomers are adjusted by their
toxicity relative to the 2,3,7,8-TCDD isomer, the concentrations
ranged from 3.2 x 10~5 to 3.9 x 10'4 ppm. These concentrations
exceeded background concentrations, but were less than the action
level of 1 x lO'3
ppm.
5.2 Hvdroqeoloqy
Groundwater in the shallow zone of the surficial water-bearing
unit flows toward the east at a seepage veloci-ty of 60 to 90 feet
per year. Groundwater in the lower zone flows toward the
southeast at.a seepage velocity of 45 to 65 feet per year.
Surface elevations at the Site range from 13 to 26 feet mean sea
level (MSL). Water table elevations at the site range from 14 to
17 feet MSL.
Interpretation of data obtained during the drilling of boreholes
into the landfill and from piezometer water levels suggest the
following: water is perched above the sludge; saturated sludge
exists within the landfill cells; and there is an unsaturated zone
beneath the sludge at least part of the year in portions of the
landfill. Figure 5-1 illustrates a typical landfill cell cross-
section. The saturated conditions within the sludge are due to
the absence of a clay cap on the landfill, the low permeability
(7xlO~7 cm/sec) of the sludge material, and the bentonite layer
beneath the sludge.
WEST
EAST
r—MOMTORMQ
\ WELL
• ••—-.--•-.••*•_•».:;^*•.*•**•'.•• ^.^-t^i'-z* ^
OF BORROW PIT EXCmwnON (AS
BV TMP ancPMVORAi Bmojruav
.BOTTOM OF BORROW PIT EXCmwnON (AS
DBWED BY THE OOEWYSICAL BOUNDARY)
sot
WATER TABLE
PERCHED WATER
Figure 5-1
Cross-Section of a Typical Landfill Cell at the Site
-------
• Private water supply wells located near the Site have been sampled
annually by Hercules since 1985. Toxaphene has not been detected
above instrumentation quantification limits in the private wells.
• Groundwater elevations at the Site exhibit minor cyclical
fluctuations that may be attributable to the tidal cycle.
. However, tidal influences are insufficient to affect basic
groundwater flow patterns.
• Toxaphene has been detected in four monitoring wells all located
at the-southeastern corner of the landfill at concentrations
ranging from 0.0056 ppm to 0.076 ppm. During the latest round of
sampling, only one well indicated toxaphene contamination,
measured at 0.069 ppm.
• Both nickel and benzene have been detected aL-ove MCLs in
groundwater samples collected adjacent to the landfill.
5.3 Surface Water
• Surface drainage occurs by overland flow at the Site. The flow at
the Site is divided by the crest of the landfill with both
westward flow toward Highway Spur 25 and eastward flow toward the
drainage ditch located immediately east of the Site. The drainage
along Spur 25 flows through a 36-inch culvert which connects to
the drainage ditch on the eastern side of the Site. . This culvert
transverses the Site immediately south of the landfill cells.
• Surface drainage from the Glynn Place Mall (approximately 1000
feet north of the Site) enters the east drainage ditch upstream of
the Site. The pond at the southern end of the Site receives
runoff only from the immediate area surrounding the pond, and has
no permanent surface inflow or outflow. This onsite pond is
believed to have been formed during the construction of Spur 25 as
a borrow pit.
• The water table is generally close to the bottom of the drainage
ditch, and groundwater flow from underneath the landfill may
seasonally discharge into the drainage ditch. The water table
configuration is, however, based on a single set of water table
elevations from a single date. Nevertheless, this data indicates
that the water table would provide only minor discharge to the
drainage ditch located immediately east of the Site.
• Surface water and sediment samples were collected in the onsite
pond and in the off-site drainage ditch. Samples in the drainage
ditch were collected both alongside the Site and over a mile away
from the Site in the estuary. Toxaphene was not detected in any
surface water samples. However, toxaphene was detected at a
maximum of 0.86 ppm in two sediment samples adjacent to the Site.
8
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Dried Stales
Environmental Protection
Aflency
Office of
Emergency and
Remedial Response
EPA/ROORCM-90/065
June 1990
CoPV/
Superfund
Record of Decision:
Harris/Palm Bay Facility, FL
legion 3
Philadelphia, PA 19107
-------
50272-101
REPORT DOCUMENTATION 1. REPORT MO. J-
PAGE EPA/ROD/R04-90/065
4. TM*md8uMM>
SUPERFUND RECORD OF DECISION
Harris/Palm Bay Facility, FL
First Remedial Action
7. Auftor(i)
9. Ptrfeimfcig OrgcMzrion Nwra and Addraw
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
X B»cipt«nf « Acc«««ion Mo.
S. fteportO**
06/28/90
i
•. l%1emihiu Organization tofrt. No.
10. ProjccVTMk/Wat* IMt No.
11. CofttracKC) or OnnKO) No.
(C)
(0)
11. Typ» at (taped • Pwtod Cownd
800/000
14.
IS.
1«. AtoMel(LMI:200MOfd«)
The 345-acre Harris/Palm Bay Facility site is an electronics manufacturing company in
Palm Bay, Brevard County, Florida. Surrounding land use is commercial, residential,
and industrial. The site overlies an unconsolidated aquifer, which is used by a public
wellfield located south of and downgradient of the site. From the 1950s to 1967, the
site was operated by an electronics firm when Harris Corporation purchased the
facility. Current facility operations are subdivided into the Government Systems
operations area and the Semiconductor Complex area. In 1981, EPA identified VOCs in
ground water wells located south of the Government Systems facility. Ground water
contamination was attributed to several onsite incidents at the Government Systems
plant including two fires, which resulted in the dumping of chemical vats, a broken
acid/solvent line, and spillage at drum storage areas. Seepage from two former
treatment lagoons may also be a source of a shallow contaminant plume. In 1985, Harris
constructed a treatment facility to implement an onsite ground water treatment and
monitoring program which is still in operation. This Record of Decision (ROD)
addresses ground water contamination at the Government Systems facility. A subsequent
(See Attached Page)
17. Do
Record of Decision - Harris/Palm Bay Facility, FL
First Remedial Action
Contaminated Medium: gw
Key Contaminants: VOCs (TCE), metals (chromium, lead), other inorganics
b. kten«**ra/0|»n-End*dT«nM
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19. 9*0
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22. Me*
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(Fonmrty MTO48)
272 (4-77)
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EPA/ROD/RO4-90/065
Harris/Palm Bay Facility, FL
First Remedial Action
Abstract (Continued)
ROD will address the contaminated ground water at the Semiconductor Complex and all of
the contaminated onsite soil. The primary contaminants of concern affecting the
ground water are VOCs including TCE; metals including chromium and lead; and other
inorganics including fluoride.
The selected remedial action for this site includes continued ground water pumping and
treatment using air stripping to remove VOCs; using the treated ground water as
industrial process water then reinjecting the treated ground water onsite into a deep
aquifer; and evaluating and modifying the existing ground water monitoring program to
fully characterize onsite contamination. The estimated present worth cost for this
remedial action is $1,430,000, which includes a total O&M cost of $950,000 for five
years.
PERFORMANCE STANDARDS OR GOALS: The goal of this remedial action is to restore the
aquifer to its beneficial use. Cleanup standards were chosen as the more stringent of
State or Federal SDWA standards. Chemical-specific ground water goals include TCE
5 ug/1 (MCL), chromium 50 ug/1 (MCL), and lead 15 ug/1 (proposed MCL).
-------
RECORD OF DECISION
DECLARATION
Site Name and Location;
Harris Corporation/Palm Bay Facility
Palm Bay, Brevard County, Florida
Statement and Basis of Purpose;
This decision document represents the selected remedial action for the
Harris Corporation/Palm Bay Facility site 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) and, to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP).
This decision is based upon the contents of the administrative record for
the Harris Corporation/Palm Bay Facility site.
The United States Environmental Protection Agency and the State of Florida
agree on the selected remedy.
Assessment of the Site;
Actual or threatened releases of hazardous substances from this site, if
not addressed by implementing the response action selected in this Record
of Decision (ROD), may present a current or potential threat to public
health, welfare, or the environment.
Description of Remedy;
The first operable unit defined for this site is the contaminated
groundwater associated with the Harris Corporation Government Systems
facility. Through treatment and engineering controls, this operable unit
remedy eliminates or reduces the risks associated with the site due to
exposure to contaminated groundwater via the public water supply.
The major components of the selected remedy include:
continued operation of the existing extraction, treatment, and
disposal system;
- extraction of contaminated groundwater from the surficial
aquifer
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treatment of the extracted groundwater by air stripping the
volatile organic compounds
injection of the treated groundwater into the deep Floridan
Aquifer, which is not a source of potable water in the area
* a design analysis to determine the effectiveness of the existing
system for plume containment and treatment
' modification of the system based on results of the design analysis
0 continued sampling in order to monitor progress of the cleanup
' a review of the site within five years after initiation of remedial
action in order to ensure protectiveneas of the remedy
Statutory Determinations;
The selected remedy is protective of human health and the environment,
complies with Federal and State requirements that are legally applicable
or relevant and appropriate to the remedial action, and is
cost-effective. This remedy utilizes permanent solutions and alternative
treatment (or resource recovery) technologies to the maximum extent
practicable and satisfies the statutory preference for remedies that
employ treatment that reduces toxicity, mobility, or volume as a principle
element. As this remedy will initially result in hazardous substances
remaining on-site above health-baaed levels, a review will be conducted
within five years after commencement of remedial action to ensure that the
remedy continues to provide adequate protection of human health and the
environment.
« 2 8 «»
Greer C. Tidwcll, Regional Administrator x Date
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Record of Decision
The Decision Summary
Harris Corporation/Palm Bay Facility
NFL Site
Palm Bay, Brevard County, Florida
Prepared by:
U.S. Environmental Protection Agency
Region IV
Atlanta, Georgia
-------
TABLE OF CONTENTS
1.0 Introduction 1
1.1 Site Name, Location, and Description 1
1.2 Site History and Enforcement Activities 5
1.3 Community Participation 8
1.4 Scope and Role of Operable Units 8
2.0 Summary of Site Characteristics 9
2 .1 Site Contaminants 9
2 .2 Geology 13
2.3 Hydrogeology 13
3.0 Summary of Site Risks 19
3.1 Identification of the Contaminants of Concern (Indicator
Chemicals) 19
3.2 Exposure Assessment Summary 20
3.3 Toxicity Assessment Summary 22
3.4 Risk Characterization 23
3. 5 Environmental Risks 27
4.0 Description of Alternatives 27
4.1* Alternative 1 - No Action 27
4.2 Alternative 2 - Continued Operation of the Groundwater
Extraction and Treatment System with Deep
Well Injection 28
4.3 Alternative 3 - Modification of the Groundwater Extraction
and Treatment System 1 32
4.4 Alternative 4 - Disposal via Spray Irrigation 34
4.5 Alternative 5 - Disposal via Percolation 35
4.6 Alternative 6 - Disposal via Reinjection to the Surficial
Aquifer 37
5.0 Summary of Comparative Analysis of Alternatives 40
5.1 Overall Protection of Human Health and the Environment 40
5.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) 41
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5.3 Long-Term Effectiveness and Permanence 45
5.4 Reduction of Toxicity, Mobility, or Volume Through Treatment..45
5 . 5 Short-Term Effectiveness 47
5 . 6 Implementability 47
5. 7 Cost 48
5 .8 State Agency Acceptance 49
5.9 Community Acceptance 49
6.0 Selected Remedy 49
7.0 Statutory Determinations 51
7.1 Protection of Human Health and the Environment 51
7.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) 52
7.3 Cost-Effectiveness 52
7.4 Utilization of Permanent Solutions and Alternative Treatment
Technology or Resource Recovery Technologies to the Maximum
Extent Practicable 52
7. 5 Preference for Treatment as a Principle Element 53
LIST OF FIGURES
Figure 1 - Site Location Map 2
Figure 2 - Site Layout Map 4
Figure 3 - Government Systems Soil Sample Locations 6
Figure 4 - Isopleths of Average 1988 Total VOC Concentrations,
40-Foot Zone 10
Figure 5 - Isopleths of Average 1988 Total VOC Concentrations,
80-Foot Zone 12
Figure 6 - Generalized Geologic Column 14
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Figure 7 - Water-Level Elevations, 40-Foot Zone 17
Figure 8 - Water-Level Elevations, 80-Foot Zone 13
LIST OF TABLES
Table I - Sampling Data for Groundwater Contaminants of Concern at
Government Systems 21
Table II - Reference Doses (RfD) and Cancer Potency Factors (q*) for
Constituents Detected at Government Systems 24
Table III - Risk Characterization for Groundwater Contaminants at
Government Systems 26
Table IV - Aquifer Cleanup Levels Specified in the FDER/Harris Consent
Order 29
Table V - Government Systems Groundwater Remediation Goals 46
LIST OF APPENDICES
Appendix A - Reports on Previous Investigations Conducted at the
Government Systems Facility 54
Appendix B - Underground Injection Control Class I Permit Injection
Limits 57
Appendix C - National Pollutant Discharge Elimination System Permit
Discharge Limits 60
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RECORD OF DECISION
THE DECISION SUMMARY
HARRIS CORPORATION/PALM BAY FACILITY
OPERABLE UNIT I
PALM BAY, BREVARD COUNTY, FLORIDA
1.0 Introduction
The Harris Corporation (Harris) site was proposed for inclusion on the
National Priorities List (NPL) in April 1985. The Harris site has been
the subject of numerous investigations performed by the responsible party,
Harris Corporation, under an Administrative Order on Consent with the
State of Florida that was signed in December 1983. These previous
investigations include: 1) studies of affected groundwater, including
geologic and hydrogeologic studies; 2) studies of affected soils;
3) evaluation of methods of remediation and treatability; and
4) investigations assessing the ongoing remediation program.
1.1 Site Name, Location, and Description
The Harris Corporation/Palm Bay Facility site is located on 345 acres
along Palm Bay Road in Palm Bay, Brevard County, Florida [Figure 1]. The
site consist* of groundwater and soils contamination associated with
Harris Corporation including the groundwater plumes extending from Harris
onto the adjacent property owned by General Development Utilities (GDU).
Harris Corporation manufactures electronic components as well as
communication and information processing equipment. There are two major
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m
r-
O
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H i
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operating divisions, the Government Systems (now called Electronic
Systems) and the Semiconductor Complex. Harris acquired a third area,
Building 100, in 1970.
GDU, a subsidiary of General Development Corporation, provides the public
water supply and "sewage treatment and disposal for at least 33,000
residents of Palm Bay. The GDU well field consists of 25 producing
wells. A number of these wells are located directly south of, and
downgradient from, the Government Systems facility.
Harris Corporation has been operating the Government Systems facility in
Palm Bay since 1967. Harris purchased Radiation Corporation, an
electronics firm supporting the space industry, which operated at the site
from the 1950's to the early 1960's. All expansion from the original
buildings has been onto undeveloped property with the exception of
Building 100. Two previous manufacturing firms (Sorban and Mohawk Data
Services) operated at Building 100 and used the site for painting
operations, a chromium plating operation, a machine shop, and a drum
storage area.
The Harris site is surrounded to the east, west, and north primarily by
commercial and other industrial-zoned properties which in turn are bounded
by residential properties. A municipal park, known as Knecht Park, lies
east of the site. Site usage is not expected to change.
The significant surface features present include several small bodies of
water on the Harris property/ a pond in Knecht Park, and Turkey Creek
[Figures 1 & 2]. The Harris ponds are primarily used for stormwater
retention, although some are used for irrigation. The site is within the
drainage basin of Turkey Creek and its tributaries which lie to the
southwest, south, and southeast. Stormwater runoff that is not retained
on-site is discharged to the municipal stormwater drainage system and
eventually into Turkey Creek.
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Clear monl Street
rn
•8
»t
General
Development
Utilities. Inc
1 1'
I ipscomb Street
51
55
I I
L
n 7"
7
Sernic onduclor
Complex
r." i
6J
H
6?A
X«?^l
rr:3
Robert J Conlan tllvd
Not to Scale
HARRIS CORPORATION
SUPERFUND SITE
Palm Bay, Brevard County, Florida
SITE LAYOUT MAP
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1.2 Site History and Enforcement Activities
In 1981, the EPA sampled GDU production wells which lie south of Harris
Government Systems facility as part of a nationwide survey of groundwater
quality. In March 1982, the EPA reported to the Florida Department of
Environmental Regulation (FDER) that numerous volatile organic compounds
(VOCs) were detected in six GDU production wells. Harris confirmed the
presence of VOCs in monitor wells on the Government Systems property in
1982. Harris entered into a Consent Order with FDER (OGC Case No.
82-0582) in December 1983 with Amendments in January, 1984 and October,
1984. Harris agreed to conduct a groundwater investigation to determine
the extent of chemical impacts and to develop and implement a groundwater
restoration program. Since entering into this agreement, Harris, with
FDER oversight, has conducted numerous investigations, installed 134 wells
at Government Systems, and conducted groundwater sampling.
Although not all incidents involving the release of hazardous substances
have been identified, some contributing events are known. Two fires
occurred in the northeast corner of Building 6, one in 1967 and another in
1974. Chemical vats were dumped by the fire department and flushed out
through holes which were broken into the floor of the building. The
volume of chemicals released in these two incidents is unknown.
Several possible source areas have been identified at Harris based on
knowledge of past operating and handling practices. The volume of
materials released is not known. From 1968 to 1970, storage drums
containing paints, solvents and similar materials were stored in the area
of the northeast corner of Building 6 and along the western sides of
Building* 10 and 11. In the late 1960's an acid and solvent line between
Building 6 and a metal-finishing waste treatment plant apparently leaked.
As a result, source areas may include the stormwater drain extending from
this area eastward to the drainage swale along Perimeter Road and to two
former treatment lagoons located in the southeast corner of the site
[Figure 3].
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A i — i
u 1 — 1
n
U
/ITL-TLn
100
L.
nf>iMf»iT mar /
m_<* aa *mm ,
LEGEND
• SOIL SAMPLE LOCATIONS
0 SUSPECTED POSSIBLE CHEMICAL SOURCE LOCATION
*CO
— «
GOVERNMENT SYSTEMS SOL SAMPLE LOCATIONS
Figure 3
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In addition, Building 5 ia located on the former site of two
neutralization lagoona that were cleaned out in 1980. A neutralization
ditch was located south of these lagoons which conveyed water to the two
treatment lagoons already mentioned. East of Building 15 is an area
suspected to be the location of an old trash site. The old pump and lift
stations are also potential sources of contamination. More recently,
Harris documented a 1986 acid line leak in the area of Building 4.
The estimated VOC plume configurations indicate that the major source area
is probably near Building 6. Therefore, the major sources may be the
fires, broken solvent line, and drum storage areas near Building 6. The
treatment lagoons previously located near Building 5 may be a source for
the shallow plume in that area.
The Harris Corporation site was proposed for the National Priorities List
(NPL) on April 1, 1985, and became a final NPL site on July 1, 1987. EPA
issued a general notice letter to Harris Corporation on April 6, 1989,
notifying Harris of its potential liability under the Comprehensive
Environmental Response and Liability Act of 1980 (CERCLA). This notice
letter was issued pursuant to Section 104 and other provisions of CERCLA
as amended by the Superfund Reauthorization Act (SARA). In this notice
letter, EPA recognized the remedial efforts taken by Harris Corporation at
the site* in compliance with the Consent Order executed between Harris and
the State of Florida.
FOER elected to assume management of enforcement activities at the site
due to this existing agreement. EPA has provided technical support by
reviewing site documents including the sampling and analytical results.
Previous investigations conducted by both Harris and GDU have included
studies assessing the nature and extent of chemical impacts on the
groundwater and soils, methods of remediation, and assessments of the
ongoing remedial action. Appendix A lists the reports for studies that
have been conducted to perform Contaminant Assessment Plan and Feasibility
Study activities.
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1.3 Community Participation
The EPA Proposed Plan for the Harris Corporation site was released to the
public in March, 1990. This Proposed Plan, along with technical reports
prepared by Harris relating to Contaminant Assessment Plan and Feasibility
Study activities, was placed in the Administrative Record. The decision
for this site is based on documents found in the Administrative Record.
The Administrative Record is located in an information repository
maintained in each of two locations: the EPA Records Center in the Region
IV office in Atlanta, Georgia, and the Palm Bay Public Library in Palm
Bay, Florida. The notice of availability for these documents was
published in the Florida Today newspaper on March 18, 1990. EPA mailed a
fact sheet on March 16 to each person on the site-related mailing list.
On March 23, EPA issued a press release announcing the public meeting,
comment period, and document availability.
A 30 day public comment period was held from March 18, 1990 through April
17, 1990. In addition, a public meeting was held on March 27, 1990 in
Palm Bay. At this meeting, representatives from EPA and FDER presented
information and answered questions about the problems at the site and the
actions taken to date. EPA responses to the comments received during this
period are included in the Responsiveness Summary, which is part of this
Record of Decision.
1.4. Scope and Role of Operable Units
As with many Superfund sites, the problems at the Harris Corporation site
are complex. Therefore, EPA has divided the Harris site into a minimum of
two operable units (OUs) for better management of the response activities.
These operable units are:
OU One: Contaminated groundwater associated with Government Systems
OU Two: Contaminated groundwater at the remainder of the site
(including the Semiconductor Complex and Building 100) as
well as contaminated soils at the entire site
-------
This Record of Decision addresses only Operable Unit One, contaminated
groundwater associated with the Government Systems facility. Under
oversight from PDER, this operable unit is currently in remediation using
a groundwater treatment system.
Remediation of th'e groundwater at the Semiconductor Complex is scheduled
to begin in late 1990, also under FDER oversight. Additional soil
sampling to identify contaminant source locations along with treatability
studies may be necessary as part of Operable Unit Two. Any interim
actions will be consistent with any planned future actions.
2.0 Summary of Site Characterization
The chemical characterization of groundwater for Operable Unit One at the
site has been studied and monitored since 1984. Appendix A lists the
studies conducted by both Harris and GDU which provide documentation
concerning the nature and extent of chemical impacts upon the aquifer.
2.1 Site Contaminants
Contaminants identified at the Government Systems facility can be divided
into four categories: volatile organic compounds (VOCs), acid extractable
organics (AEOs), metals, and fluoride. These contaminants are associated
with processes conducted at Government Systems.
VOCs
The contamination has been approximated vertically and horizontally and is
tracked by a network of monitor wells. Two significant, affected
groundwater zones have been identified in the Government Systems area:
the 40-foot zone and the 80-foot zone. There are two VOC plumes
identified in the 40-foot zone [Figure 4]. One plume lies near Building 5
at the eastern edge of the site in the vicinity of the old stormwater
drain outfall and treatment lagoons. The other plume is located near
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•4
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o I ii
LI UNO
MAKHIS CUKI'UKAlltlN UKUIIUH Mil
ISlX'll III U AV1KAG1 I9MM IOIAI V(IC', (I'AHM, I'lH HI11ION)
HARRIS CORPORATION GOVERNMENT SYSTEMS
BOPLETHS OF AVERAGE 1988 TOTAL VOC CONCENTRATIONS
40-FOOT ZONE
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11
Building 6. The VOC plume in the 80-foot zone of the leaky artesian
aquifer extends from the area near Building 6, and continues
south-eastward toward and across the southeast boundary of the Harris
property [Figure 5].
AEO8
Harris conducted testing for acid extractable organics (AEOs) in
groundwater from. 90 wells across the site after trace levels of phenols
were detected. Subsequent analyses showed the level of AEOs to be below
detection limits except for a phenol concentration of 20 ug/1 in a sample
taken in 1986 from Well GS-37S, one of the Harris extraction wells.
Metala
Metals above the EPA and Florida Maximum Contaminant Levels (MCLs) were
detected in some shallow well-point samples collected during
reconnaissance testing in 1986 around Building 6. Chromium and lead were
the metals of primary concern. Subsequent groundwater sampling of
permanent monitor wells at Harris shows these and other metals (cadmium,
silver, and mercury) to be below detection limits. As a result,
monitoring wells are no longer routinely sampled for metals.
Fluoride
Shallow well-point samples delineated an area of elevated fluoride
immediately west and south of Building 4. Harris performed a follow-up
study which found one well (GS-M14) with significantly high fluoride
levels (6.64-6.68 mg/1). In order to detect any migration of fluoride,
monitoring for this compound also occurs in the surrounding wells.
Fluoride has been detected in groundwater only at the 15-foot depth, not
the 40- and 80-foot depths. There is insufficient evidence to conclude
that fluoride is moving laterally or vertically with the groundwater.
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•8
S
LEGEND
HARRIS CORPORATION UONIIOR WHIL
ISOPUTM OF AVIRAU 1988 1OIAI VOC'S (PARIS PER BIUIUN)
HARRIS CORPORATION GOVERNMENT SYSTEMS
BOPLETHS OF AVERAGE 1968 TOTAL VOC CONCENTRATIONS
80-FOOT ZONE
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13
2.2 Geology
Physiographically, the Harris site is on the Atlantic Coastal Ridge, part
of the Pamlico Terrace. This surface is a relict beach ridge thought to
have formed about 125,000 years ago (late Pleistocene) when sea level was
approximately 25 fco 30 feet above the present level. Land surface
elevation at Harris is approximately 19-22 feet above sea level.
The subsurface geology of coastal Brevard County is relatively uniform.
The Harris site is located in an area where the surficial deposits are
unconsolidated sediments approximately 110 feet deep. These deposits are
comprised (in descending order) of undifferentiated Holocene sediments,
the Fort Thompson and Anastasia Formations of Pleistocene age, and Tamiami
Formation of Pliocene age. These sediments are relatively flat-lying,
fine to medium grained sand layers containing variable amounts of clay,
shell fragments, carbonate and organic material. The clay layers are
discontinuous and occur intermittently. Several distinct layers of
reddish-brown, sandy silts are found in the upper 40 feet of sediments.
At depths between 4 and 12 feet, a hardened silt layer is found that has
been referred to as a "hardpan".
Underlying the upper surficial deposits, starting at about 90 to 110 feet,
are clay layers of the Miocene age Hawthorn Formation. This formation is
comprised of clayey silts and sands, phoephatic sediments and limestone,
and is between 100 and 200 feet in total thickness. Below the Hawthorn
Formation, from about 330 to 1920 feat below land surface, the
stratigraphic section is dominated by interbedded limestones and dolomites
of the Eocene age Ocala Limestone, Avon Park Formation and Lake City
Limestone. Underlying this section is the Oldsmar Formation of Lower
Eocene age extending to a depth of approximately 2640 feet which is also
dominated by limestone and dolomite units. Figure 6 shows a generalized
geologic column for the site.
2.3 Hydrogeology
Both Harris and GDU have completed studies on the characterization of the
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14
El«v»non
(M««n
$41
— 10 —
— .10 —
— .JO -
-.40 —
Monuonng
Zontt
Llyw
^~ 'S-foct Monitonng
— .70 —
— M -
-.JOS -
- X —
- 30 —
- 40 —
— M —
- M —
- 70 —
— M —
— M —
— ,00 —
— IX —
80-Foo
' Sana
SOURCE
Compiltd from Pott. BueU«y, Schuh and Jtmigan Inc..
Oacembcr 1963; Gcraahty 4c Milter. Inc., November 1907;
and G«ragnty ic Miller. Inc.. July 1987.
HARRIS CORPORATION
GROUNDWATER PROGRAM
GENERAUZED GEOLOGIC
COLUMN
Pigur« 6
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15
hydrologic properties of the subsurface sediments. These studies include
direct measurement of hydrologic conductivity by laboratory analysis of
water flow through core samples as well as indirect calculation of the
estimated permeability based on particle size analysis. Harris conducted
aquifer tests at Government Systems in addition to the aquifer tests
performed as part of the development of the GDU wellfield. Geophysical
investigations of the permeability and stratigraphy of subsurface layers
have been completed using electro-magnetic, resistivity, and
ground-penetrating radar surveys. Pump tests show how the pumping at GDU
affects the aquifer. In addition, several studies characterize the
potentiometric surface from water level measurements.
An unconfined water table aquifer lies in the upper portion of the
surficial unconsolidated deposits to a depth of approximately 40 to 60
feet. At that depth, a relatively low-permeability (3 gpd/ft ) dominant
clay layer containing fine sand and shell separates it from a lower, leaky
artesian aquifer. This lower artesian aquifer extends to a depth of
approximately 90 to 110 feet and is underlain by impermeable clay layers
of the Hawthorn Formation.
The transmissive aquifer layers are dominated by shell hash containing
variable amounts of sand and clay [Figure 6]. The estimated average
transmissivity of the unconfined water table aquifer is 3420 gpd/ft. The
clay layer lying between the two aquifers has an estimated average
transmissivity of only 24 gpd/ft. This clay layer acts as an aquitard for
downward migration of groundwater. (Estimated transmissivities of the
lower zone of high permeability leaky artesian aquifer range from 7600 to
15800 gpd/ft in this area.) The lower zone of high permeability is about
20 to 40 feet thick and lies at depths of about SO feet. This zone is the
principal water-producing zone from which water supplies are drawn by
GDU. Below the lower shallow aquifer are impermeable clay layers of the
Hawthorn Formation which form an aquiclude below the production zone and
separate this shallow aquifer from the confined Floridan Aquifer below.
The Floridan Aquifer exists under artesian conditions in the area with
potentiometric levels above land surface. As a result, there is no
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16
recharge to the Floridan Aquifer from the surficial aquifer. The FLoridan
Aquifer iiea within the limestones and dolomites of the Ocala Group, Avon
Park Formation and the Oldsmar Formation. Water level measurements in
wells completed in the surficial aquifer (including the water table and
leaky artesian aquifers) establish that the potentiometric surface (water
level contour) La at shallower depths on the north side of Harris than on
the south side. Baaed on these water level measurements, a hydraulic
gradient exists across the Harris site toward the south and southeast
[Figures 7 & 8].
Field tests done with GDU wells pumping and then with the wells turned off
demonstrate that the potentiometric surface and hydraulic gradient are
significantly influenced by pumpage of the GDU production wells located
south and southeast of the site. Under static conditions (i.e., GDU
production wells turned off), the hydraulic gradient in the production
zone (leaky artesian aquifer, 80-foot zone) was estimated to be about
0.004 ft/ft (about 20 ft/mile). With the GDU wells pumping, the hydraulic
gradient averages 0.01 ft/ft (about 50 ft/mile) which is greater than two
times the static gradient. The hydraulic gradient at the southeast corner
of the site is calculated to be 0.0035 ft/ft. During another
investigation, the gradient was calculated to be 0.0094 ft/ft. The
groundwater gradient is much steeper in the 80-foot zone than in shallower
zones due to the influence of the GDU wellfield. As a result, this
gradient creates a potential for the downward movement of groundwater from
shallower zones. Using the estimated hydraulic conductivities and
porosities of the transmissive layers, groundwater flow rates are
estimated for the 15-foot, 40-foot, and 80-foot zonea to be 16, 77 and 273
ft/year, respectively.
The climate in the Palm Bay area is subtropical humid, with the winter
months being generally dryer than the summer months. As part of the
modeling of the hydrologic regime at the site, Harris Corporation
researched a number of the parameters related to the climate of the area.
Average rainfall in this area is about 56 inches per year. Adjusting for
evapotranspiration and surface runoff, the estimated effective recharge of
the shallow aquifer is 36 inches per year.
-------
• MAHHI3 CORPORATION VOC
Ht COVLHV Will
WA IEM I t VI I ttt «» IION
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-------
N
HAHHIS COflPOHAtlON VOC
RECOVt R y WE LI
GENERAL DEVELOPMENT
LHILIIIES. INC WELL
WATER-LEVEL ELEVAIION
IN FEE 7 (HOW MSl
It H-LEVEL ELEVAIIONS
buHJOl ZONE
3/24/6S
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19
3.0 Summary of Site Risks
.EPA performed an evaluation of the baseline public health and
environmental risk associated with the Harris site. This baseline
evaluation helps determine whether or not a remedial action is necessary
by identifying the risk poaed by the site if no remedial action is taken.
The baseline assessment also provides the framework for developing the
preliminary remediation goals for the site.
EPA has determined that actual or threatened releases of hazardous
substances from this site may present an imminent and substantial
endangerment to public health, welfare, or the environment. In order to
address this potentially imminent and substantial endangerment, EPA
recommends the implementation of the response action selected in this ROD.
3.1 Identification of the Contaminants of Concern (Indicator Chemicals)
Groundwater is the media of concern for Operable Unit One. The
contaminants of concern are primarily volatile organic compounds (VOCs),
but also include acid extractable organics (AEOs) and inorganic
compounds. These contaminants have been selected based on site-specific
data collected by Harris as part of initial sampling efforts as well as
the ongoing monitoring program at the Government Systems facility. The
identified contaminants of concern consist of compounds which are the most
toxic, mobile, and presently persistent chemicals related to this operable
unit.
The indicator chemicals for this site were based on an analysis of the
compounds identified in groundwater sampling conducted by Harris. The
analysis for VOC contamination involved data from a 1989 sampling event.
The analyses for metals and fluoride utilized less recent data because
sampling for these compounds has been less frequent than for VOCs. Data
from wells where no contaminants of concern were detected have been
excluded. In calculating the averages across all wells sampled, one-half
the detection limit was used for those contaminants not detected (if at
least one contaminant of concern was detected in that well).
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20
Table I shows the concentrations for groundwater contaminants of concern
based on samples collected from monitoring wells at Government Systems and
GDU. These groundwater samples contained elevated concentrations of the
following nine VOCs: 1,1-dichloroethane (1,1-DCA), 1,1-dichloroethylene
(1,1-DCE), methylene chloride (MC), trichloroethylene (TCE), vinyl
chloride (VC), chlorobenzene (CB), 1,2-dichlorobenzene (1,2-DCB),
1,2-dichloroethylene (1,2-DCE), and ethyl benzene (EB). In addition,
metals (chromium, lead, and copper) as well as fluoride were reported as
present in the groundwater associated with Government Systems.
Chromium, lead, and copper as well as other metals had previously been
detected beneath the Harris facility at levels above water quality
standards. Subsequent sampling by Harris showed steadily declining levels
of these metals. In addition, the most recent data analyzed by EPA
indicates that chromium was detected in only one well and copper is not
found at levels of concern. Analyses for metals at GDU indicate that
metals are not detected at levels above drinking water standards.
FOER conducted split sampling at Harris in 1985. The results of this
sampling were used to confirm the methodology and quality assurance of the
Harris sampling procedures as well as the analytical results obtained.
3.2 Exposure Assessment Summary
This ROD addresses the groundwater exposure pathway. The potential human
exposure pathway of primary concern is ingestion. Other water use
pathways include dermal contact and inhalation.
The preliminary classification for the contaminated groundwater aquifer is
class II, a potential or existing drinking water source. Class II
aquifers should be remediated to levels that are protective of human
health.
GDU is located directly south of the Harris facility. Groundwater flow at
the site is to.the south, southeast towards the GDU facility which
provides the public water supply for Palm Bay. Therefore, the potential
receptors of contaminated groundwater in the absence of groundwater
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21
Table I
Sampling Data for
Groundwater Contaminants of Concern at Government Systems
Carcinogens
Maximum
Concentration
(uq/U
Mean
(uq/Ua
Number
of
Samples
Frequency
of
Detection
1,1-Dichloroethane
1,1-Dichloroethylene
Methylene Chloride
Trichloroethylene
Vinyl Chloride
1790
671
26
1860
2280
123
50
5
311
323
29
29
29
29
29
22
8
3
16
18
Noncarcinoqena
VOCi
1,1-Dichloroethane
1,1-Dichloroethylene
Methlyene Chloride
Chlorobenzene
1,2-Dichlorobenzene
1,2-Dichloroethylene
Ethyl Benzene
1790
671
26
16
19
240
76
123
50
5
3
5
84
13
29
29
29
29
29
29
29
22
8
3
10
8
24
5
Chromium
Lead
Copper
Mercury
Fluoride
30
80
c
56
8580
3181
8
9
12
15
1
7
0
11
a - This concentration represents the 95 percent upper confidence limit on
the arithmentic average.
b - This category includes carcinogens which are also considered to have
noncarcinogenic toxic effects.
c - Chromium was only detected at one sampling location.
d - Copper was not detected at levels of concern.
e - Mercury was not detected. However, the detection limit that was used
is 2.5 times greater than the EPA required quantitation limit.
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22
remediation are the Palm Bay residents. If the remediation program is
discontinued, the contaminated groundwater will migrate further into the
GDU well field. Also, groundwater from the shallow zone of the aquifer
could potentially discharge to Turkey Creek which runs south of the
facility. In that event, the creek could become a human health and/or
environmental exposure pathway.
Another potential human exposure pathway of concern is the inhalation of
off-gassing from the air stripping system. During pilot testing of the
air stripping tower at Harris, FDER analyzed projected air emissions.
This analysis indicated that the volume of emissions is not high enough to
present an unacceptable health risk. EPA performed a similar analysis in
February, 1990 to confirm these results. However, since the FDER
analysis, exposure limits for some volatile organic compounds, including
vinyl chloride, have been reduced by the Occupational Safety and Health
Administration (OSHA) and the American Conference of Governmental and
Industrial Hygienists (ACGIH). Therefore, the health risks associated
with the air stripper emissions should be reviewed based on these new
limits.
The risk calculations for the ingestion of groundwater are based on the
exposure point concentrations which represent the upper (95 percent)
confidence limit on the arithmetic average. The arithmetic average is
based on sampling data collected from wells in the area of the groundwater
contamination. The exposure assumption used in the risk assessment is
that an exposed individual consumes two liters of the untreated water
daily for 70 years.
3.3 Toxicity Assessment Summary
Cancer potency factors (CPFs') have been developed by the EPA Carcinogenic
Assessment Group for estimating excess lifetime cancer risks associated
with exposure to potentially carcinogenic chemicals. CPFs, which are
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23
expressed in units of (mg/kg-day) are multiplied by the estimated
intake of a potential carcinogen, in mg/kg-day, to provide an upper-bound
estimate of the excess lifetime cancer risk associated with exposure at
that intake level. The term "upper bound" reflects the conservative
estimate of the risks calculated from the CPF. Use of this approach makes
underestimating the actual cancer risk highly unlikely. Cancer potency
factors are derived from the results of human epidemiological studies or
chronic animal bioassays to which animal-to-human extrapolation and
uncertainty factors have been applied [Table II].
Reference doses (RfDs) have been developed by EPA for indicating the
potential for adverse health effects from exposure to chemicals exhibiting
noncarcinogenic effects. RfDs, which are expressed in units of mg/kg-day,
are estimates of lifetime daily exposure levels for humans, including
sensitive individuals. Estimated intakes of chemicals from environmental
media (e.g., the amount of a chemical ingested from contaminated drinking
water) can be compared to the RfD. RfDs are derived from human
epidemiological studies or animal studies to which uncertainty factors
have been applied (e.g., to account for the use of animal data to predict
effects on humans). These uncertainty factors help ensure that the RfDs
will not underestimate the potential for adverse noncarcinogenic effects
to occur [Table II].
Hexavalent chromium is a human carcinogen when inhaled. However, oral and
dermal exposure have not been identified as carcinogenic. The volatile
organic contaminants of concern in the groundwater at the Harris facility
which are considered to be carcinogens from oral exposure are 1,1-DCA;
1,1-DCE; MC; TCB; and VC. The inorganic constituents in the site
groundwater are not considered to be carcinogenic from the oral exposure
route. Therefore, the hazards associated with these constituents are
lower than for the five potential carcinogenic VOCs.
3.4 Risk Characterization
A hazardous waste risk assessment considers the likelihood that adverse
effects will occur as a result of exposure to chemicals released into the
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24
Table II
Reference Doses (RfD) and Cancer Potency Factors (q*)
for Constituents Detected at Government Systems
Constituent
Reference Dose
Oral
(mg/kg/day)
Cancer Potency Factor EPA
Oral Classi-
(mg/kg/day) fication
Oroanics
Trichloroethylene
Vinyl Chloride
1,1-Dichloroethane
1,1-Dichloroethylene
Methylene Chloride
Chlorobenzene
1,2-Dichlorobenzene
t-1,2-Dichloroethylene
Ethyl Benzene
0.12
0.009
0.060
0.027
0.089
0.020
0.10
0.011
2.3
0.091
0.6
0.0075
B2
A
B2
C
B2
D
D
D
D
Inorganics
Mercury
Chromium
Copper
Fluoride
Lead
A -
Bl =
B2 =»
C -
D -
0.0003 D
0.0050 D(oral)
D
0.060 D
0.0014 B2
Human Carcinogen (sufficient evidence in humans)
Probable Human Carcinogen (limited evidence in humans)
Probable Human Carcinogen (limited evidence in animals)
Possible Human Carcinogen (limited evidence in animals)
Inadequate evidence of animal or human carcinogenic ity
Agency verified toxicity number is not available
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25
environment. The risk assessment includes carcinogenic as well as
noncarcinogenic effects.
Excess lifetime cancer risks are determined by multiplying the intake
level with the cancer potency factor. These risks are probabilities that
e
are generally expressed in scientific notation (e.g., 1x10 or 1E-6).
An excess lifetime cancer risk of lxlO~ indicates that, as a plausible
upper bound, an individual has a one in one million chance of developing
cancer as a result of site-related exposure to a carcinogen over a 70-year
lifetime under the specific exposure conditions at a site. The Agency
considers individual excess cancer risks in the range of lxlO~ to
IxlO"6 as protective. However, the 1x10 level is generally used as
the point of departure for setting cleanup goals at Superfund sites.
Table III contains the concentrations that are equivalent to a 1x10
risk level.
Table III also contains the excess cancer risks associated with a
groundwater exposure level representing the 95 percent upper confidence
limit of the mean. This mean value, shown in Table I on page 21, is based
on an analysis of Harris sampling data. Therefore, a potential source of
uncertainty in this risk assessment is based on the methodology (discussed
in Section 3.1) used to determine the mean values for contaminants in the
groundwater.
Potential concern for noncarcinogenic effects of a single contaminant in a
single medium is expressed as the hazard quotient (or the ratio of the
estimated intake derived from the contaminant concentration in a given
medium to the contaminant's reference dose). By adding the hazard
quotients for all contaminants within a medium or across all media to
which a given population may reasonably be exposed, the Hazard Index can
be generated. The hazard index provides a useful reference point for
gauging the potential significance of multiple contaminant exposures
within a single medium or across media. EPA has not prepared a hazard
index for this site. However, Table III contains the hazard quotients for
the mean (upper 95 percent confidence limit) groundwater concentration for
the noncarcinogens. This table also contains the concentration that is
equivalent•to the reference dose.
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26
Table III
Risk Characterization for Groundwater Contaminants
at Government Systems
Carcinogens
1,1-Dichloroethane
1,1-Dichloroethylene
Methlyene Chloride
Trichloroethene
Vinyl chloride
Groundwater
Risk Level
Maximum/Average
4.6 x
1.1 x
5.5 x
5.7
10~3/3.
10"2/8.
x 10'4/9
1 x 10
3 x 10
10
10
1 x
6 x
1.5 x 10~V2.1 x 10
-4
-4
-6
-5
-2
10 Excess
Cancer Risk
Concentration
(ug/1)
0.39
0.06
4.80
3.20
0.02
Noncarcinogens
1,1-Dichloroethane
1,1-Dichloroethylene
Methylene Chloride
Chlorobenzene
1,2-Dichlorobenzene
1,2-Dichloroethylene
Ethyl Benzene
Mercury
Chromium
Copper
Fluoride
Hazard Quotient
Maximum/Average
4.
2.
1.
1.
6.
3.
2.
4.
3
1
2
6
2
4
2
1
x
x
X
X
X
X
X
X
10
10
10
10
10
10
10
1.
10
-1
0
-2
-2
-3
-1
-2
7
0
/2
/I
/2
/3
/I
/I
/3
c
X
e
/I
.9
.6
.5
.6
.6
.2
.8
10
.5
x
x
X
X
X
X
X
-1
X
10
10
10
10
10
10
10
10
-2
-1
-3
-3
-3
-1
-3
0
Concentration
Equivalent to
RfD (ug/ll b
700
63
420
140
630
140
700
2
35
420
This category includes carcinogens which are also considered to
have noncarcinogenic toxic effects. Hazard values were not
quantified for lead since there are no current agency verified
toxicity values for lead.
This concentration represent* the groundwater concentration
equivalent to the RfD and a 20% relative source contribution.
Mercury was not detected. However, in some cases, the detection limit
used is 2.5 times greater than the CLP required quantitation limit.
Chromium was detected above the detection limit in only one well.
The maximum hazard quotient was based on the data from this well
and the RfD for hexavalent chromium.
The Hazard Quotient was not calculated because there is no RfD.
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27
3.5 Environmental Risks
Under natural conditions, shallow groundwater discharges to Turkey Creek
which runs south of the facility. At present, due to the pumping by GDU
and the Harris groundwater extraction system, groundwater is reportedly
not discharging to Turkey Creek. However, if the pumping is discontinued
prior to complete remediation, terrestrial and aquatic organisms could be
exposed via contaminated surface water. Discharge to surface waters via
stormwater run-off is another potential environmental risk.
The National Oceanic and Atmospheric Administration (NOAA) review of site
conditions identifies Turkey Creek as the principal area of either surface
discharge or groundwater discharge. Future work on the remaining operable
unit(s) should include sampling of the creek sediments in order to verify
that past releases did not leave potentially toxic levels of contaminants
in Turkey Creek.
4.0 Description of Alternatives
EPA considered six alternatives for the remediation of the groundwater
associated with Government Systems. All of these alternatives are based
on the use of the existing aeration treatment system operating at
* «
Government Systems.
In order to document all remedial alternatives considered at the site,
this Record of Decision includes options eliminated early in the
evaluation process. These options were reviewed by Harris prior to
selecting th« existing system and are presented here as Alternatives 4, 5,
and 6. Th« comparison of all alternatives is based on a maximum system
throughput of 750,000 gpd.
4.1 Alternative 1 - No Action
The Superfund Program requires that the "no-action" alternative be
considered at every site. Under the "no-action" alternative, EPA would
take no further action at the site to control or treat the source of
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28
contamination. The "no-action" alternative aerves as a baseline with
which other alternatives can be compared. "No action" would involve
shutting down the existing groundwater extraction and treatment system on
each of the Harris and GDU properties. While this alternative does
include groundwater monitoring, the only reduction of contaminant levels
would be via natural processes such as dispersion. Potential health risks
would remain from ingestion of, or dermal contact with, untreated
groundwater. Furthermore, discharges into Turkey Creek could potentially
result in a threat to terrestrial and aquatic organisms there.
The present (1990) value cost of this alternative is approximately
$355,000. This estimated coat includes shutting down the existing
treatment system at $50,000 and groundwater monitoring for five years at
$61,000 per year.
4.2 Alternative 2 - Continued Operation of the Groundwater Extraction
and Treatment System with Deep well Injection
Alternative 2, Continued Operation of the Groundwater Extraction and
Treatment System with Deep Well Injection, is currently being performed at
the site pursuant to a Consent Order with the State of Florida. Table IV
lists the aquifer cleanup levels specified in the FDER/Harris Consent
Order.
Groundwater withdrawal is accomplished with a combination of 11 wells, six
in the 80-foot zone and five in the 40-foot zone. VOCs are then removed
and treated by a relatively simple multistage air stripping process. The
treated water is currently used in a manufacturing process before being
injected approximately 2500 feet deep into the lower Floridan Aquifer.
The Floridan Aquifer is saline and nonpotable in the area. This injection
process is regulated by FDER and EPA through an Underground Injection
Control (UIC) permit for a Class I non-hazardous industrial well.
The existing system was implemented in three stages as described beginning
on page 30.
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29
Table IV
Aquifer Cleanup Levels Specified
in the FDER/Harris Consent Order
Consent
Agreement
Constituent
Design
Specification
(uq/L>
Trichloroethylene
<5
1,1-Dichloroethylene
<5
Cis-l,2-Dichloroethylene
<5
Trans-1,2-Dichloroethylene
<5
Vinyl Chloride
<5
1,1,1-Trichloroethane
<5
1,1-Dichloroethane
<5
Methylene chloride
<2S
Ortho-Dichlorobenzene
<25
Chlorobenzene
<25
Ethyl Benzene
<25
Toluene
<25
* This concentration la higher than the current MCL or pMCL.
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30
Stage 1:
To create a hydraulic capture zone on the southern boundary of the
Harris Corporation Government Systems facility, Harris instituted an
extraction program involving three wells (GS-123D, GS-124D, and
GS-125D). These well positions allow for interception of contaminated
water from the deep zone of the main VOC plume. The three wells
create a cone of depression upgradient from the GDU production wells.
The planned pumping rate of each of the hydraulic barrier wells was
25 gpm each. Field checks by Harris in 1985 indicated the following
production rates for the hydraulic barrier wells:
well . Rate
GS-123D 40 gpm
GS-124D 53 gpm
GS-125D 52 gpm
Stage 2:
Another deep extraction well (GS-127D) and 10 well points in the
shallow zone were added during Stage 2, in order to initiate
remediation activities in two areas. These areas were: (1) the
highly contaminated shallow zone near Building No. 5 and (2) the
southern part of the deep zone contaminant plume in the Government
Systems parking lot. Well GS-127D is identical in construction to the
three barrier wells used in Stage 1 and is equipped with a 50-gpm
(nominal) submersible pump discharging to a header that transmits
contaminated groundwater to the groundwater treatment system. Well
GS-127D produced 50 gpm during continuous pumping of Stage 1 and Stage
2 wells in 1985. The well point system installed as part of Stage 2
allowed for the extraction of groundwater from contaminated areas of
the shallow zone. These well points were designed to have a jetting
shoe below the screen to allow installation by jetting. Two well
point pumps provided the vacuum to run the system. The combined
pumping rate of the 10 well points during Stage 1 and Stage 2
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31
operation was about 30 gpm (measured at the groundwater treatment
system). These well points were eventually replaced with two
permanent wells, GS-44S and GS-18S.
Stage 3:
Implementation of Stage 3 allowed for the extraction of the most
highly contaminated portion of the plume, in the vicinity of Building
6. Six additional wells were added during this stage: GS-35S
(shallow or 40-foot zone), GS-35D (deep or 80-foot zone), GS-37S,
GS-37D, GS-43S, and GS-43D. These wells are grouped in three pairs,
with each pair consisting of a shallow zone and a deep zone well. All
six wells are equipped with 50-gpm (nominal) submersible pumps. The
shallow and deep zone extraction wells are operated at the pumping
rates of 25 and 50 gpm respectively.
Treatment System Description:
The extracted groundwater flows through a network of pipes to a
treatment system which removes VOCs by a packed column air stripping
tower. The packed column aeration system is widely used for the
removal of VOCs from contaminated drinking water. Contaminated
groundwater is delivered from the extraction wells to a 20,000-gallon
raw water holding tank. The raw water is pumped to the top of the
6-foot diameter tower and distributed over the packing media by a
weir-trough distributor. The water cascades over 25 feet with
counter-current air flow supplied by a forced draft centrifugal
blower. The stripping tower is mounted on top of the 20,000-gallon
treated water holding tank. Tower effluent flows by gravity into the
holding tank and is then pumped to a water reuse system on the site.
The treated groundwater ia used for process water under a Consumptive Use
Permit issued by the St. Johns River Water Management District. After use
as process water, the treated groundwater is disposed of by deep well
injection into the lower Ploridan Aquifer. This injection process
utilizes a Class I non-hazardous well with an Underground Injection
Control (UIC) permit monitored by FDER. The Ploridan Aquifer is not
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32
considered to be a potable water source in this area due to high Total
Dissolved Solids (TDS) and chloride concentrations.
In addition to the system operating on the Harris facility, there is a
groundwater extraction and treatment system ongoing at the GDU facility.
Water from seven-production wells is pumped to an air stripper. The
stripper effluent is mixed with water from other GDU production wells
before undergoing the standard water purification process prior to public
consumption. The construction and monitoring of this system has been
funded by Harris. An informal agreement exists between Harris and GDU
such that GDU is to provide Harris six months advance notice in the event
that GDU sells its property.
The existing treatment, disposal, and monitoring system has been
implemented in stages since 1984. Alternative 2 would involve the
continued use of this existing system for at least another three years.
The present value (1990) cost of Alternative 2 is estimated to be
$792,000. This cost includes operation and maintenance of the existing
system and groundwater monitoring for three years at a total of $264,000
per year.
4.3 Alternative 3 - Modification of the Groundwater Extraction and
Treatment System
Alternative 3 involves continued operation of the existing extraction and
treatment system aa well aa a modification of the system. This
modification will ba designed to improve the capture- of site-related
contaminant plume* and optimize system effectiveness.
Modification is necessary to better define the contaminant plumes, ensure
containment of these plumes, and enhance the efficiency of aquifer
cleanup. Source characterization indicates the possible presence of
metals and AEOs in the groundwater. The analyses to date do not
adequately define this contamination. Therefore, modifications may be
needed to more adequately monitor and, if necessary, treat this potential
contamination in the groundwater.
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EPA developed a list of proposed modifications for the purpose of
estimating costs associated with Alternative 3. These modifications may
include, but are not limited to: (1) installing approximately four
additional extraction wells, (2) discontinuing the use of some existing
wells, and (3) decommissioning monitoring wells that are no longer of use
but are determined to be located in source areas. The exact number of
wells affected and any altered pumping rates will be determined during the
remedial design phase.
The remedial design will include a detailed design analysis of the
existing system to determine the location of additional wells. It will
also address, if necessary, the discontinued pumping of any existing
wells. The design may include a schedule for temporarily shutting down
the entire system to determine remedial action success. A shut-down would
be initiated only after contaminant levels in the aquifer met the
specified cleanup goals. This shut-down would allow the groundwater to
recharge and reach an equilibrium condition. Additional sampling and
analyses as well as careful monitoring of the aquifer could then determine
whether or not the sources of contamination had been removed.
The existing groundwater monitoring program will be evaluated and modified
as necessary to fully characterize the extent of contamination at the
site. The modified monitoring program will be implemented for a period of
three years or until the cleanup goals are met. After the onset of
remedial action, EPA will conduct a review of the site within five years
to verify that the aquifer is being restored to beneficial use. If the
cleanup goals appear to be met after the first review, sampling would
continue annually or semi-annually for a period of time necessary to
verify that long-term restoration of the aquifer had occurred. However,
if the review identifies a need for further remedial action, monitoring,
or attainment of cleanup goals, the appropriate action will be initiated.
The present (1990) value cost for this alternative is estimated at
$1,430,000. This estimated cost includes design modifications and
construction of additional wells at a cost of $480,000. Also included is
$950,000 for three years of system operation and maintenance as well as
five years of groundwater monitoring.
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4.4 Alternative 4 - Disposal via Spray Irrigation
This alternative would utilize the aame groundwater extraction and
treatment system described in Alternative 2. However, the method for
disposal of treated groundwater involves spray irrigation with discharge
to a drainage ditch.
Spray irrigation relies on two natural forces to dispose of water,
evapotranspiration and percolation. Of the two, percolation is the
predominant disposal method. Several design criteria are critical in
evaluating a spray irrigation system: the amount of available acreage on
which to apply the treated groundwater, hydraulic assimilation capacity of
the site, and the application rate of the water.
The area has two major soil types, a satellite sand and MyaJcka sand. The
estimated percolation rate of this area is approximately 0.6 inches/hr.
Based on a hydrologic budget model prepared for the site, the average
maximum hydraulic load the site could support is 3.9 inches per week.
However, standing water has been observed throughout the dry season. This
phenomenon is the result of improper drainage brought about by development
on three sides of the site, creating a berming effect. In order to meet
the requirements for spray irrigation, fill material would need to be
brought i'n to raise the area approximately three feet.
In addition to its poor drainage, this site is further restricted by
Section 17-6 of the Florida Administrative Code (FAC), which limits the
hydraulic loading of alow rat*
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One of the principal disadvantages of using a spray irrigation system is
its dependence on weather conditions. Spray irrigation systems cannot be
operated during or after periods of heavy or prolonged rainfall. During
rainy periods, the treated groundwater would have to be stored or
discharged to the drainage ditch. The spray irrigation system is also
more labor intensive because the system must be switched on and off
manually to meet the changing weather conditions and to avoid flooding of
the area.
Environmentally, spray irrigation is attractive because it provides a
secondary method of aerating the treated groundwater, and a portion of the
water will be percolated back into the surficial aquifer for reuse. The
principal environmental disadvantage is that almost half of the water will
be discharged to the drainage ditch.
Harris does not currently have sufficient acreage for complete spray
irrigation. In addition, the cost of bringing in fill to elevate the area
is prohibitive. Environmentally, spray irrigation is preferable to
reinjection. However, spray irrigation would be too land intensive,
requiring approximately 100 acres of land to spray irrigate 750,000 gpd.
Treated water would then have to be pumped approximately five miles.
Site-specific features thus reduce the technical feasibility of
Alternative 4. EPA did not estimate the costs associated with this
alternative because it was eliminated early in the evaluation process and
no current cost data exists.
4.5 Alternative 5 - Disposal via Percolation
This alternative utilizes the same groundwater extraction and treatment
system described in Alternative 2. However, the method of disposal of
treated groundwater would be to return the treated water to the surficial
aquifer through a percolation pond with overflow to a drainage ditch.
For this alternative, several simplifying assumptions were made regarding
the hydrogeology of the available eight acre tract. The firat assumption
was that the aquifer is an unconfined, homogeneous, isotropic, single-
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layer system. (In reality, the site geology is known to be more complex
and actually consists of three layers: an upper aquifer, an aquitard, and
a lower aquifer.) Second, the assumed average permeability of the
single-layer system was 150 gpd/ft . This value was determined by
proportioning the measured permeability values and thickness of each of
the three geologic layers. Third, the assumed average aquifer thiclcness
was 93 feet, based on previous geological investigations. Other data used
in this analysis include the following:
o average ground surface elevation at the site is +18' MSL
o average groundwater piezometric surface at the site is +10' MSL
o estimated distance to the Turkey Creek outfall is 2,500 feet
o percolation rate is 63 gal/day lineal foot of pond
o estimated water surface elevation at the Turkey Creek outfall is
less than +2' MSL
o assumed maximum percolation pond water surface is +22" MSL
o assumed maximum usable pond area is 625' x 525' (7.45 acres),
based on the berm configuration
These data and a modified version of Darcy's Law, led to the conclusion
that the maximum seepage flow available at the 8 acre tract is about
40,000 gpd. However, the achieveable seepage rate at the site is probably
much leas than 40,000 gpd, because the actual subsurface conditions are
less favorable for percolation than assumed in this analysis. Further,
the actual hydraulic gradient may also prove to be lower than the gradient
assumed for this analysis. One alternative would be to construct a
percolation pond on the 8 acre tract and allow the overflow to discharge
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to the drainage ditch. This would mean that during normal operating
conditions, approximately 40,000 gpd would enter the soil and up to
710,000 gpd of treated groundwater would be discharged to surface waters.
There are several factors to be considered regarding the environmental
impact of a percolation pond. On the positive side, the 8 acre pond would
provide a 110 day retention time for treated water entering the pond,
which would allow for further volatilization of any VOCs. The negative
aspect to the percolation pond is that once the pond is filled, up to
710,000 gpd of treated water must be discharged to the surface waters and
cannot be returned to the aquifer for use. In addition, volatilization
will occur only at the surface interface unless an aerator is used to
enhance volatilization of less accessible areas.
Harris does not currently own enough acreage adjacent to the Government
Systems facility to construct a percolation pond to dispose of 750,000 gpd
solely through percolation. Construction of a smaller percolation pond on
the available land will allow percolation of an estimated 40,000 gpd. The
remainder of the treated water will flow to the drainage ditch. The use
of percolation ponds is not feasible, because there is insufficient
acreage available to construct a percolation pond large enough to dispose
of most of the treated groundwater. No current cost data exists for this
alternative.
4.6 Alternative 6 - Disposal via Reinjection to the Surficial Aquifer
This alternative utilizes the same groundwater extraction and treatment
system described in Alternative 2. However, the method of disposal of
treated groundwater involves returning the treated water to the surficial
aquifer via reinjection wells.
A review of the hydrogeological characteristics of the Harris site shows
that reinjection into the surficial aquifer could take place in either of
the two permeable zones present. The upper portion of the surficial
aquifer is located from approximately +17' to -20' MSL and has an average
permeability of 95 gpd/ft2. The lower portion of the aquifer is located
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from -30' to -80' MSL, with an average permeability of 200 gpd/ft2.
Based on the transmissivity and permeability of the surrounding areas, 20
to 30 four-inch diameter shallow wella with five-foot screens capable of
reinjecting 2 to 3.5 gpm would be required to inject 100,000 gpd treated
water into the upper aquifer. The deeper zone of the surficial aquifer
would require only three six-inch diameter wells with ten-foot screens
reinjecting approximately 23 gpm to dispose of 100,000 gpd treated water.
In order to achieve maximum utilization of the available reinjection area,
the wells must be located in lines running east and west, generally
perpendicular to the north-south direction of groundwater flow. The
required distance between wells is based on the cone of influence. This
distance would be about 30 feet for the shallow wells and 200 feet for the
deeper wells.
In selecting the system location, the first consideration is to position
the reinjection wells outside the zone of influence associated with the
groundwater withdrawal wells. This positioning is necessary to avoid a
reduction in radius of influence of a given withdrawal system, and to
avoid repumping treated groundwater. The only available reinjection area
not in the zone of influence of the groundwater withdrawal wells is an
eight acre tract located east of Perimeter Road on the Government Systems
facility. Either two rows of 15 shallow wells each or three deep wells
could be installed in this tract.
The presence of an aquitard at -20' to -28' MSL is another condition to
consider. Th« aquitard limits the amount of water which can be injected
into the shallow reinjection wells. Too great a reinjection rate will
cause an upflow of the water, which could result in ponding. However, the
aquitard has a positive effect on the deeper reinjection wells by acting
aa a barrier preventing water from rising to the surface.
The increased pressure applied to the aquifer should check any further
dispersion of the contaminants to the east by establishing wells east of
the suspected area of contamination. In addition, the reinjected water
can be returned to the aquifer instead of being lost to surface water
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discharge. However, there La a potential for introducing trace amounts of
VOCs into groundwater currently considered free of these contaminants.
The existing groundwater treatment system has been designed to remove VOCs
to the prescribed levels in the Harris/PDER Consent Order. This system
also has operating safeguards such as an automatic shutdown in the event
of a malfunction in the air stripping tower fan.
Despite these precautions, the possibility exists for inadvertently
contaminating the aquifer due to the lag time between sampling the treated
effluent and receiving the analytical laboratory results. Use of a 1.2
million gallon treated water holding tank would eliminate the possibility
of discharging contaminated water into the aquifer. However, prior to
initiating reinjection, an acceptable air to water ratio for achieving the
concentration limits established in the Consent Order would be set during
start-up activities. Once the normal operation begins, this ratio is
expected to be fairly consistent. Therefore, failure of the tower fan is
the only likely means of introducing contaminated groundwater into the
clean zone of the aquifer. The motor control system design addresses this
contingency. In the event of tower fan failure the influent pumps
automatically shut down. As a result, the system would not require large
holding tanks.
The preferred zone of reinjection would be outside the area of
contamination in the lower surficial aquifer, which is more permeable,
requires fewer wells and prevents ponding. Environmentally, reinjection
offers two positive aspects. Pressurizing the aquifer will prevent the
spread of VOC contamination to the east and allow the treated water to be
reused by placing the water back into the surficial aquifer. The
potential for reinjecting contaminated water back into a clean area may be
reduced by incorporating the proper instrumentation and motor control
switches to avoid discharge of contaminated water if the fan motor fails.
The information presented thus far for Alternative 6 relates to the
reinjection of 100,000 gpd. In order to accommodate the reinjection of a
maximum of 750,000 gpd, 20 additional deep reinjection wells would be
required across the Government Systems property. However/ according to
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Harris, placement of the reinjection wells around the site would be
difficult due to the extensive network of underground utilities. As with
Alternatives 4 and 5, no current cost data for this alternative exists.
5.0 Summary of Comparative Analysis of Alternatives
EPA uses nine criteria for evaluating remedial alternatives at NPL sites.
The first two are known as threshold criteria and are the minimum
requirements that all alternatives must meet: overall protection of human
health and the environment and compliance with site-specific cleanup
standards. There are five balancing criteria used for comparison of the
alternatives: long-term effectiveness; reduction of toxicity, mobility,
or volume; short-term effectiveness; implementability; and cost. The last
two, state acceptance and community acceptance, are known as modifying
criteria and can serve to influence the EPA preferred remedy.
5.1 Overall Protection of Health and the Environment
Alternative 1, No Action, would allow for the continued migration of
contaminants to the GDU wellfield downgradient of the site. This
alternative is not considered effective because it does not mitigate
potential health risks associated with exposure to groundwater by
ingestion and dermal absorption. Alternative 1 exceeds the 1 x 10 to
1 x 10 target risk range and, therefore, is not protective of human
health and the environment. The No Action Alternative will not be
considered further aa a remedial option for this site.
Alternative* 2 through 6 are protective of human health and the
environment baaed on the use of air stripping treatment for VOCs. By
providing a barrier for contaminant migration as well as treatment of the
contaminant plume, these alternatives mitigate the risk of migration to
the GDU well field and other potential users of the aquifer. The capture
zone of the extraction system prevents migration as well as discharge of
contaminated groundwater to surface water, thus avoiding a potential
environmental threat.
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5.2 Compliance with Applicable or Relevant and Appropriate Requirements
(ARARS)
Remedial actions performed under CERCLA must comply with all site-specific
Applicable or Relevant and Appropriate Requirements (ARARs). The ARARs
for this site can be grouped into six categories. The Harris remediation
system must comply with cleanup standards from: the Safe Drinking Water
Act (SDWA), the Underground Injection Control (UIC) program, the National
Pollutant Discharge Elimination System (NPDES), the Resource Conservation
and Recovery Act (RCRA), the State of Florida Administrative Code (FAC),
and the Clean Air Act (CAA).
All alternatives except for the No Action Alternative would comply with
ARARs. "No Action" would allow contaminants to remain in the groundwater
at concentrations above drinking water standards. This level of
contamination would violate the SDWA and FAC. Alternatives 2-6 assist in
restoring the levels of contaminants in the aquifer to drinking water
standards and, therefore, lead to compliance with the SDWA and FAC. Water
injected into the Floridan Aquifer in Alternatives 2 and 3 would meet the
UIC permit requirements. Water discharged to the drainage ditch in
Alternatives 2 and 3 would meet NPDES permit limits. In Alternatives 2-6,
the extracted groundwater would be treated to meet health-based standards
prior to disposal and would, therefore, meet the current RCRA Regional
guidance regarding contaminated groundwater. Finally, emissions from the
air stripper used in Alternatives 2-6 would meet National Ambient Air
Quality Standards.
Safe Drinking Water Act
The SDWA mandate* EPA to protect human health from contaminants in
drinking water. Since the groundwater in the area of the Harris site is
an existing drinking water source, the aquifer is classified as Class II
groundwater. Therefore, the SDWA standards set by EPA are relevant and
appropriate.
EPA has developed two types of drinking water standards, primary and
secondary standards. Primary standards are based upon protection of human
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health. These Maximum Contaminant Levels (MCLs) are enforceable at the
federal level. MCLs are contaminant-specific standards and are potential
ARARs for affected potable water at NPL sites. Section 121(d)(2)(b)(i) of
CERCLA prescribes that these standards, as determined by the Safe Drinking
Water Act (SDWA) (40 CPR Part 141 and 142) and Section 304 of the Clean
Water Act, should be used in setting cleanup goals for response actions at
NPL sites. Secondary standards (SMCLs) are often concerned with the
aesthetic quality of water as well as economic considerations and are not
enforceable at the federal level. However, SMCLs are in the category of
standards "to-be-considered" (TBC) as ARARs in order to protect the
groundwater for future use.
For some constituents, there are no primary or secondary standards
established pursuant to the SDWA. In this event, concentrations of
contaminants in groundwater remaining at the completion of the remedial
action must still be protective of human health and the environment. For
carcinogens, the one in one million (1E-6) cancer risk level is considered
adequately protective of human health. For non-carcinogens, a threshold
value may be determined from the currently available EPA toxicological
data base. If a proposed MCL (pMCL) is available for a constituent, it
may also be used. Proposed MCLs are not enforceable standards, but are
considered TBCs.
«
In summary, Alternatives 2 through 6 meet the ARARs for VOCs based on use
of the aeration treatment system. The primary ARARs that apply to aquifer
remediation are the MCLs promulgated under the SWDA. These are applicable
where water will be provided directly to 25 or more people or to 15 or
more service connections. MCLs are relevant and appropriate when the
surface or groundwater is used or may be used for drinking water. "To be
considered" remediation goals, including proposed MCLs and risk based
calculations, apply when a population is exposed to contaminants.
Underground Infection Control
The Safe Drinking Water Act also provides for a permit program which is
designed to prevent contamination of underground sources of drinking
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water. This program is known as the Underground Injection Control (UIC)
program. The UIC program regulates underground injection into five
classes of wells. There are two Class I permitted injection wells present
on the Harris Corporation Government Systems facility for the disposal of
industrial waste water. These wells are not currently permitted for the
injection of hazardous waste. Therefore, the groundwater must be treated
to health-based standards as described in the Table III on page 26 before
injection.
Alternatives 2 and 3 involve additional ARARs for the deep well injection
of treated groundwater into the Floridan Aquifer. The Floridan Aquifer is
not a potential source for drinking water because it is saline and
nonpotable. The UIC permit administered by PDER lists the injectate
limits as shown in Appendix B.
National Pollutant Discharge Elimination System (NPDES)
In addition, the extraction and treatment system described in Alternatives
2 and 3 must comply with the National Pollutant Discharge Elimination
System (NPDES) standards under the Clean Water Act (CWA). Currently,
discharges from the treatment system to the drainage ditch east of
Perimeter Road may occur during equipment failure or emergencies. As an
alternative to deep well injection, the treated groundwater can be
discharged to the surface through this permitted NPDES outfall. Any
surface water discharge flowing into this ditch eventually runs into a
tributary of Turkey Creek. The current NPDES discharge limits are listed
in Appendix C.
Resource Conservation and Recovery Act
The volatile organic compounds present in the groundwater associated with
Government Systems are characterized as spent solvents. Spent solvents
are RCRA "listed" hazardous wastes as defined in 40 CFR 261.31. Since it
contains a listed hazardous waste, the contaminated groundwater must be
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managed as a hazardous waste. As a result, groundwater containing
hazardous waste cannot be injected into the Class I injection wells at the
site. To do so would be in violation of RCRA and UIC requirements,
including the Land Disposal Restrictions. After treatment to health-based
levels, which the Harris system accomplishes, EPA considers that the
groundwater no longer contains hazardous waste. Once these health-based
levels are reached, the groundwater is no longer subject to regulation
under Subtitle C of RCRA.
In addition, EPA has determined that Resource Conservation and Recovery
Act (RCRA) technical standards regarding corrective action and closure are
relevant and appropriate for the groundwater plumes and contaminant source
areas at Government Systems. Corrective action on any portion of the site
determined to be releasing contaminants to the groundwater will comply
with RCRA technical standards.
Florida Administrative Code
EPA considers all appropriate state standards as potential ARARs. The
State of Florida has requested that EPA include the Florida Administrative
Code (FAC) requirement that the aquifer be cleaned up to a level such that
the groundwater is "free from nuisance". EPA has determined that the
"free from" requirement, a secondary standard pursuant to the SDWA, is
relevant and appropriate for this site. The existing Consent Order
between FDER and Harris lists protective standards for aquifer cleanup.
These standards are considered to meet the "free from" criteria for the
site.
Clean Air Act
Emissions from the air stripper used in Alternatives 2-6 must meet ambient
air standards from the National Ambient Air Quality Standards (Section 109
of the Clean Air Act as set forth in 40 CFR Part 50).
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Cleanup Goals for Operable Unit One
Table V is a list of the site-specific contaminants and the appropriate
cleanup levels based on the ARARs discussed above. These cleanup levels
are based on MCLs, the FAC "free from" requirements, pMCLs, 1E-6
health-based risk values, and SMCLs as appropriate for each contaminant
listed.
The State of Florida MCLs that are more stringent than federal standards
will be used as ARARs. In addition, the cleanup criteria identified in
the FDER/Harris Consent Order will be used to meet the FDER "free from"
requirements. This approach provides for consistent application of the
FDER Consent Order with respect to EPA response goals.
5.3 Long-Term Effectiveness and Permanence
Alternatives 2-6 mitigate the risk to the population of exposure to
contaminated groundwater. The extraction and treatment system used in all
of these alternatives adequately reduces the exposure to VOCs in the
groundwater. Alternative 3 allows for enhanced control of contaminant
migration by making the system more efficient in treating for VOCs as well
as addressing the potential for AEO and inorganic contaminants.
Alternative 3 would also remediate the groundwater to a long-term
acceptable risk range. Alternative 6 involves some risk due to the
reinjection of treated groundwater to the surficial aquifer. In
Alternative 6, this riak is associated with the potential exposure to
contaminant* in the drinking water from downward migration to the lower
aquifer.
5.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternatives 2-6 reduce the toxicity and volume of the contaminants in
groundwater through treatment. In addition, these alternatives limit the
mobility of contaminants by decreasing the size of the contaminant plume
and/or eliminating part of the source through the use of extraction
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TABLE V
Government Systems Groundwater Remediation Goals
Concentration
Contaminants (ppb) Basis
Vinyl chloride
Trichloroethylene
1, 1-Dichloroethylene
c-1, 2-Dichlorethylene
Methylene chloride
1, 1-Dichloroethane
Chlorobenzene
t-1 , 2-Dichloroethylene
1 , 2-Dichlorobenzene
Ethyl benzene
Toluene
1,1, 1-Trichloroethane
Trichlorobenzene
Lead
Mercury
Chromium
Copper
1
3
5
5
5
5
25
5
25
25
25
5
25
15
2
50
1000
MCL (1)
MCL (1)
CO
CO
1E-6, pMCL, TBC
CO
CO
CO
CO
CO
CO
CO
CO
MCL ( 2 ) , TBC
MCL
MCL
SMCL
Fluoride 2000 SMCL
MCL Maximum Contaminant Level
(1) The State of Florida has promulgated MCLs for TCE and
VC which are more stringent than EPA's MCLs, therefore,
the State MCLs are ARARs for the Harris Site.
(2) The present MCL for lead is 50 ppb. A level of 15 ppb
has been proposed as a health-based standard and is,
therefore, a to-be-considered (TBC) site cleanup goal.
CO These standards are listed in the 1983 FDER/Harria Consent
Order and are considered to be the "free from" criteria
identified in the Florida Administrative Code.
TBC To-be-con*idered cleanup goal
1E-6 One in one million excess cancer risk level
pMCL Proposed Maximum Contaminant Limit (40 CFR/ Vol. 54, No. 97/
May 22, 1989)
SMCL Secondary Maximum Contaminant Level
Notet This list does not include cleanup goals for acid extractable
organica (AEOs) because current sampling data do not identify
specific AEOs.
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wells. Alternative 3 not only allows for more efficient reduction of the
contaminant plume, it allows for treatment of the potential groundwater
contamination from metals, fluoride, and AEOs.
5.5 Short-Term Effectiveness
Alternatives 2-6 eliminate the immediate risk to the general population of
exposure to contaminated groundwater. Any short-term risk to workers
involved in construction of the selected remedy would be reduced through
implementation of a health and safety plan.
The environmental impact of alternatives 2 and 3 is minimal since
groundwater is reinjected into the deep Floridan Aquifer which is not a
potable water source in the area. Alternatives 4 and 5 pose some
environmental impact to aquatic organisms exposed to the surface water and
any volatile organics. Alternative 6 poses an environmental threat to the
surficial aquifer by potentially introducing trace amounts of VOCs to an
area currently considered free of contamination.
Alternatives 2 and 3 would each require an estimated three years to
implement. Implementation time frames for Alternatives 4 through 6 are
not applicable because these alternatives were considered and eliminated
at an early stage of the project.
FDER estimates that Alternative 2 will substantively meet the cleanup
criteria stated in the FDER Consent Order within three years.
Implementation of Alternative 3 will take approximately three years and
will produc* information necessary to estimate the time required for
restoration of th« aquifer to EPA standards.
5.6 Implementability
The implementability of an alternative is based on technical and
administrative feasibility, constructibility, and the availability of
materials and services needed to implement a specific remedy.
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Alternatives 2 and 3 are technically and administratively feasible. These
two alternatives involve technologies which have been used in the past and
have a demonstrated performance record. The groundwater recovery,
treatment, and disposal system specified in Alternative 2 is already
operational. Alternative 3 also utilizes this system, but with
modifications. Alternatives 4 and 5 are not currently implementable due
to a lack of available land. Alternative 6 is not administratively
feasible because of the potential for contamination of a drinking water
aquifer in the event of equipment failure. The technical feasibility is
questionable because of the uncertainties in our ability to predict its
effect on the physical characteristics of the aquifer. For example,
reinjection into the surficial aquifer may introduce indeterminate
influences on the existing groundwater flow patterns.
EPA policy allows for interim remedies at sites involving groundwater
contamination. An interim remedy can be location-specific or
medium-specific and should be used when there is enough existing
information to effect the remedy. A limited evaluation of alternatives
can be used to compare the advantage of taking an early action to the
possible ramifications of waiting until a comprehensive site investigation
has been completed. An interim groundwater extraction and treatment
system at Harris has served to protect the drinking water supplied by
GDU. As a result, the phased implementation of the existing treatment
system produced data that can be used in optimizing the system
during the modifications to be determined in Alternative 3.
5.7 Cost
The present worth value represents the total cost of remediation expressed
in today's dollars. The present worth cost associated with Alternative 1
is approximately $355,000. Alternative 2 has an estimated present worth
cost of $792,000, including Operations and Maintenance (O&M) costs. The
estimated present worth cost of Alternative 3 is $1,430,000, including O&M
costs. The costs associated with Alternatives 4 through 6 have not been
estimated because these alternatives were eliminated early in the
evaluation process and no current cost data is available.
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5.8 State Agency Acceptance
The State of Florida, as represented by the FDER, concurs with the use of
Alternative 3 for Operable Unit One. This alternative is acceptable to
FDER with provisions that the FDER is a part of the review process for the
design analysis. In an early action designed to capture the contaminant
plume and protect the GDU wellfield, FDER approved the use of Alternative
2 after also considering Alternatives 4-6.
5.9 Community Acceptance
EPA received comments from local citizens at the public meeting held on
March 27, 1990 and during the public comment period. Responses to
specific comments are available in the Responsiveness Summary for this
Record of Decision. Based on these comments, the community supports the
EPA decision to modify the existing groundwater extraction and treatment
system at the Harris site.
6.0 Selected Remedy
Operable Unit One addresses the groundwater contamination associated with
the Government System* facility of Harris Corporation. The selected
remedy for this operable unit is Alternative 3, which requires
modification to the existing groundwater extraction and treatment
system.
This remedy consists of: (1) continued operation of the existing
extraction, treatment, and disposal system, (2) a design analysis for
plume containment and treatment, (3) modification of the system based on
results of the.design analysis, (4) continued sampling and monitoring of
the cleanup, and (5) a review of the system by EPA and FDER within five
years after the onset of remedial action. This remedy includes the
current deep well injection of groundwater treated to EPA health-based
levels. As an alternative, the treated groundwater will be discharged to
the surface through a NPDES permitted outfall.
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Implementation of Alternative 3 will improve the treatment and containment
of the existing groundwater extraction and treatment system. it will
involve a review of existing sampling data as well as the resampling of
wells outside the plume as defined by Harris. This alternative will
determine the effects of the present remediation system in accordance
with existing EPA policy. The effects to be determined include the
current and future effects of the air emissions from the air stripping
towers at Harris and GDU. In addition, EPA will determine the
effectiveness of plume containment with respect to VOCs, AEOs, and
inorganics as well as the effects of the various groundwater pumping
regimes in the immediate area. Furthermore, Alternative 3 does not
involve significant additional capital costs to attain these measures.
As part of the design analysis, "point of compliance wells" will be
designated in order to detect the presence of contamination above cleanup
standards. Sampling information obtained from these wells will be used to
determine exact locations of the plumes and design groundwater extraction
modifications for compliance with the RCRA technical standards.
The cleanup goals for this alternative are listed in Table V on page 46.
These cleanup levels may be modified in accordance with later guidance
and/or regulations. In addition, the goals may be modified due to
potential uncertainties about the ability of the treatment system to
achieve established cleanup goals within the existing physical groundwater
system.
The Interagency Section 7 Consultation Process, 50 CFR Part 402, requires
that EPA consult with the Department of Interior, the Fish and Wildlife
Service, and the National Marine Fisheries Service as appropriate during
remedial design. This consultation will assure that endangered or
threatened species are not adversely impacted by implementation of this
remedy. EPA has already consulted with the National Oceanic and
Atmospheric Administration on the potential environmental risks posed by
the site.
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51
7.0 Statutory Determinations
The EPA and FDER have determined that this remedy will satisfy the CERCLA
statutory requirements for providing protection of human health and the
environment, attaining ARARs related to other federal and state
environmental statutes, is cost-effective, and utilizes either permanent
solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable.
At the date of this decision, the selected remedial action meets all
Federal and State requirements. However, EPA is currently reviewing
Harris compliance with the FDER UIC program as well as the Safe Drinking
Water Act. As a result of this review, Harris may be required to make
modifications as necessary.
7.1 Protection of Human Health and the Environment
The selected remedy of groundwater extraction, treatment, and deep well
injection to the Floridan Aquifer is protective of human health and the
environment. By containing the contaminant plume, treating the
contaminated groundwater, and removing the sources of contamination, this
remedy will eliminate the contaminant plume. This remedy will eliminate
the risk of migration to the GDU well field and the entire potable
aquifer. By reducing the level of contamination in the groundwater, this
remedy will reduce the carcinogenic and noncarcinogenic risks associated
with exposure to the untreated groundwater.
The existing treatment system was designed for treating groundwater in
order to meet cleanup levels established in the FDER/Harris Consent
Order. In this system, treated groundwater is discharged to the Floridan
Aquifer rather than to surface water and, as a result, presents no
environmental risk. This water is presently recycled for manufacturing
use as exhaust scrubber water before disposal via deep-well injection.
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52
7.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs)
This remedy assures that the contaminated aquifer will be cleaned up to
meet appropriate MCLa under the SDWA. For those chemicals that do not
have an assigned- MCL, the ARARs based on to-be-considered health-based
values, FAC "free from" requirements, or SMCLs will be attained.
Discharge from the groundwater treatment system will meet either the UIC
permit injection standards or NPDES permit discharge limits under the
CWA. The treated groundwater will meet RCRA Land Disposal Restrictions
prior to disposal. The contaminant plumes will be monitored and
remediated according to the technical standards for RCRA corrective action
and closure. In addition, emissions from the air stripper will comply
with the National Ambient Air Quality Standards.
7.3 Cost-Effectiveness
The EPA selected remedy, Alternative 3, allows for a higher degree of
overall protectiveness. Modification of the existing extraction and
treatment system in accordance with the EPA groundwater remediation policy
will enhance cleanup of the aquifer. Alternative 3 requires continuation
of the.existing process for discharging the treated groundwater by
injection into the Floridan Aquifer which is a nonportable water source in
the area. However, this remedy allows for full characterization of
contamination at Government Systems and enhances the elimination of the
contaminant plume. Therefore, the selected remedy yields an overall
effectiveness that ia proportional to its increased costs.
7.4 Utilization of Permanent Solutions and Alternative Treatment
Technology or Resource Recovery Technologies to the Maximum Extent
Practicable
EPA and FDER have determined that this remedy is the most appropriate
remedy for Operable Unit One and provides the best balance among the
evaluation criteria for the remedial alternatives evaluated. Alternative
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53
3 provides both short- and long-term protection to potential human and
environmental receptors. This remedy allows for containing, treating and
eliminating the groundwater contamination in order to reduce risk from
potential exposure to the groundwater. In addition, this remedy utilizes
a proven technology for treating VOC contamination and can be implemented
year round.
7.5 Preference for Treatment as a Principal Element
Groundwater contamination with volatile organic compounds is the principal
threat at the site. Air stripping is an effective remediation method for
treating groundwater contaminated by VOCs.
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54
APPENDIX A
REPORTS.ON PREVIOUS INVESTIGATIONS
CONDUCTED AT THE GOVERNMENT SYSTEMS FACILITY
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55
Reports on Previous Investigations
Conducted at the Government Systems Facility
CH2M Hill. Phase I Report - Aquifer Contamination Studies at Port
Malabar Well Field. Document GN10067.JO. August, 1983
CH2M Hill. First Interim Report on Groundwater Contamination Studies
at Port Malabar Well Field - Phase II. Document GN16067.NO.
February, 1984.
CH2M Hill. Second Interim Report on Groundwater Contamination
Studies at Port Malabar Well Field - Phase II. Document
GN16067.NO. March, 1984
Geraghty & Miller, Inc. Building 6 Ground-water Assessment -
Government Systems - Harris Corporation, Palo Bay, Florida.
July, 1987.
Geraghty & Miller, Inc. Addendum to Building 6 Ground-water
Assessment in Palm Bay, Florida. July, 1988.
?
Geraghty & Miller, Inc. Harris Corporation National Priority List
Review of Remedial Investigations, Feasibility Studies and
Remedial Actions, Government Systems Facility. May, 1989.
Geraghty & Millar, Inc. Summary of Soils Investigations and Metals
in Ground Water, Harris Corporation, Palm Bay, Florida.
April 1990.
Post, Buckley, Schuh & Jernigan, inc. Harris Corporation -
Groundwater Studies - Vicinity of General Development Utilities
and Palm Bay, Florida - Investigations: March - October 1982.
October 21, 1982.
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56
Post, Buckley, Schuh & Jernigan, Inc. Analysis of Potential
Groundwater Withdrawal and Treatment Systems. March 8, 1983.
Post, Buckley, Schuh & Jernigan, Inc. Harris Corporation Task
B-4 - Final Report of Hydrogeological Study. Document
780-002.34. December 2, 1983.
Post, Buckley, Schuh & Jernigan, Inc. Harris Corporation Task
B-l - Soil and Sediment Investigation. Document 780-002.31.
March, 1984.
Post, Buckley, Schuh & Jernigan, Inc. Harris Corporation Task
B-2 - Surficial Groundwater and Analysis Summary Report.
Document HCf7/780-002.32. January 25, 1984.
Post, Buckley, Schuh & Jernigan, Inc. Bench-Scale Treatability Study
or Air Stripping of Selected Volatile Organics. Document
775-003.72. April, 1984.
Post, Buckley, Schuh & Jernigan, Inc. Harris Corporation Task B-8 -
Old Storm Sewer Investigation Interim Report. Document
780-002.38. May, 1984.
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57
APPENDIX B
UNDERGROUND INJECTION CONTROL
CLASS I PERMIT INJECTION LIMITS
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53
Underground Injection Control
Claaa I Permit Infection Limits
PERMITTEE:
Harris Corporation
SPECIFIC CONDITIONS:
I. D. Number:
Permit/Certification Number:
UC05-126519
Dace of Issue:
Expiration Date: 7/1/92
9. Monitoring - Deep Injection Wells
The deep injection well shall be monitored in accordance with
the requirements of Rule 17-28.26(2). F.A.C. The permittee
shall submit monthly a report which shall at a minimum include
the following data foe each injection well:
Daily specific conductance
Daily pH
Daily temperature
Daily average injection
Daily maximum injection
Daily minimum injection
Daily minimum flow rate
Daily average flow rate
Daily maximum Clow rate
Total volume discharged
Total volume discharged
Monthly avecagt of total
9. Monitoring - Treatment Plant
pressure (psi)
pressure (psi)
pressure (psi)
(gpm)
(gpm)
(gpm)
•* Daily (gallons)
-» Monthly (gallons)
volume discharge per
day
The effluent stream shall be monitored monthly for the following
parameters. A cop/ of these data shall be submitted monthly to
the Technical Advisory Committee (TAG).
Deep Well Effluent
Trichloroethane. ug/1
1.1.1.-Trichloroethane. ug/1
Methylene Chloride, ug/1
0-Dichl«obenzene. ug/1
Tetrachlocoethene. ug/1
5
5
25
5
5
DEB Form 17-1.201(5) Effective November 30. 1982 Pag* 6 of 10
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59
PERMITTEE:
Harris Corporation
SPECIFIC CONDITIONS:
I. 0. Number:
Permit/Certification Rumbec:
UC05-126519
Date of Issue:
e*pieaeion Date: 7/1/92
BOD 5 Day
Chemical Oxygen Demand (C.O.D.). mg/1
Dissolved Oxygen (D.O.). mg/1
Total Kjeldahl Nitrogen (T.K.N). mg/1 as N
Ammonia, mg/1 as N
Un-ionized Ammonia (NH3), mg/1 at N
Total Phosphorus (TP). mg/1 as P
Total Suspended Solids, mg/1
Arsenic, mg/1
Cadmium, ug/1
Chromium, mg/1
Copper, mg/1
Cyanide, ug/1
Fluoride, mg/1
Lead, mg/1
Mercury, ug/1
Nickel, mg/1
Selenium, mg/1
Silver, ug/1
Zinc, mg/1
•General Limitation;
5
10
0.05
1
10
200.0
O.OS
0.
0.
1
so
5
,2
,1
Must be compatible with the injection
system. injection zone, and confining
zone and not hazardous pursuant to
Section 17-30.03(1). Florida Administra-
tive Cod*.
The treatment plant shall be operated in such a Banner as to
maintain specific parameters within the above listed effluent
limitations.
10. Monitoring - Monitor Wells
A representative ground watec sample shall 'be obtained from the
monitoc well(s) monthly. These samples shall be analyzed for
the following parameters. The results of these analyses shall
be reported in the monthly operating report submitted to the
department.
Fluoride
Total Kjeldahl Nitrogen
pH
Chloride
TDS
Specific Conductance (field)
Total Phosphorus
Sulfate
DER Form 17-1.201(5) Effective November 30. 1982 Page 7 of 10
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60
APPENDIX C
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
PERMIT DISCHARGE LIMITS
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61
National Pollutant Discharge Elimination Syatera
Permit Discharge Limits
Page 1-1
Permit Mo.: ?L003<681
PART t
A. Epfwarr LIMITATIONS AND MONITORING RBQUIRWENTS
1. During the period beginning October 1, 1984 (or upon start-up of discharge) and lasting through the term
of this penult, the permittee is authorised to discharge froa outfall serial nunfeer 002, treated
groundwater only.
Such discharges shall be Halted and monitored by the permittee as specified below:
BrTLUENT CHARACTERISTIC DISCHARGE LIMITATIONS
kg/day (Ibs/day) Other units (Specify)
Dally Dally Dally
Average Maxtaua Average
Plow. M3/Oay (MOD)
Trlchloroethene
1,1 -d i ch loroethene
1, 2-cls-dichloroethene
1, 2-trans-dlch loroethene
Vinyl chloride
1,1,1-t rlcn lor oe thane
1,1-dlchloroe thane
Nstnyl«ne chloride
1,2 dichlorobensene
Chlorobenxene
Ethyl bensene
Ibluene
< 5juq/l
* 5>ig/l
<5;uq/l
< 5 ng/1
< 5 .wj/l
<5 ug/1
< 25
< 25
< 25
MONITOR INC REQDIUBiaiTS
Heaaureaent
frequency
Continuous
1/Wtek
I/Week
1/IHek
1/Heek
I/Keen
1/Ktek
I/Week
1/Htek
I/Wee*
1/Wtek
I/Week
Sample
Type
Recorder
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
The pR shall not be leas than 6.0 standard units nor greater than 8.5 standard units and shall be Monitored
once per week by grab sample.
There shall be no discharge of fleeting solids or visible fo«si in other than trace asounts.
Staples taken in compliance with the monitoring requireaenta specified above shall be taken at the foil owl no
locatlon(a)! nearest accessible point after final treatment but prior to actual discharge or nixing with the
receiving waters.
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RESPONSIVENESS SUMMARY
HARRIS CORPORATION / PALM BAY FACILITY
SUPERFUND SITE
PALM BAY, BREVARD COUNTY, FLORIDA
JUNE 28,1990
VOLUME I
PREPARED FOR:
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
ATLANTA, GEORGIA
EPA WORK ASSIGNMENT NO. 06-4X18
UNDER
ARCS IV CONTRACT NO. 68-W9-0048
PREPARED BY:
EBASCO SERVICES INCORPORATED
145 TECHNOLOGY PARK
NORCROSS, GEORGIA 30092
404/662-2300
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RESPONSIVENESS SUMMARY
HARRIS CORPORA!ION/PALM BAY FACILITY SUPERFUND SITE
TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1
2.0 OVERVIEW OF THE PROPOSED PLAN 3
3.0 BACKGROUND ON COMMUNITY INVOLVEMENT 5
4.0 SUMMARY OF COMMENTS RECEIVED AND AGENCY RESPONSE 7
4.1 Health Issues 7
4.2 Technical Issues 19
4.3 Air Quality Issues 24
4.4 Water Treatment Issues 25
4.5 Local Well Water Supply Issues 26
4.6 Soil Testing Issues 27
4.7 Water Utility Cost and Service Issues 29
4.8 Harris Corporation Comment 30
4.9 General Development Utilities Comment 36
5.0 REMAINING PUBLIC CONCERNS 39
Exhibits
Exhibit 1 Exposure and Odor Parameters for Various 14
Volatile Organic Compounds
Exhibit 2 Degradation Reaction of Trichloroethylene 21
Exhibit 3 Government Systems Soil Sample Locations 28
Attachments
A Proposed Plan Fact Sheet
B Press Release and Legal Notice
C Media Coverage
D Record Of Public Meeting Attendance
E Transcript of Public Meeting
F Public Meeting Handouts
G Written Public Response
H Harris Corporation Response
I General Development Utilities Responses
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1.0 INTRODUCTION
A public meeting addressing the Harris Corporation/Palm Bay
Facility Superfund Site was held by the U.S. Environmental
Protection Agency (EPA), Region IV, at the Palm Bay Community
Center in Brevard County, Florida on March 27, 1990. The meeting
was chaired by Ms. Camilla Warren, Chief of the South Florida
Superfund Section. Other attendees from the EPA Region IV office
in Atlanta, Georgia were Ms. Gail Scogin, Superfund Remedial
Project Manager for the site; Ms. Suzanne Durham, the Superfund
Community Relations Coordinator; Ms. Becky Fox, Regional
Toxicologist and Mr. Robert James from the Office of Regional
Counsel. Mr. Joe Applegate, State Project Manager with the Florida
Department of Environmental Regulation (FDER) and Mr. Larry Sims
from Geraghty & Miller, Incorporated, a consultant for Harris
Corporation, presented information on the site history and actions
taken to date.
The purpose of the meeting was to inform the public of the
groundwater remediation alternatives considered at the Government
Systems facility on the Harris site and to discuss the alternative
preferred by EPA. EPA first presented the evaluation of
alternatives and the preferred alternative in the Superfund
Proposed Plan Fact Sheet mailed to members of the community on
March 16, 1990 (Attachment A). This Fact Sheet was also made
available to the public along with the Administrative Record at the
Palm Bay Public Library. EPA announced the public meeting and
document availability in a legal advertisement in the Florida Today
Sunday newspaper on March 18, 1990 (Attachment B). The fact sheet
and legal notice announced the public comment period which began
on March 18, 1990 and ended on April 17, 1990. Local newspapers
published articles on site issues on December 13, 1989 and March
25 and 27, 1990 as shown in Attachment C.
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This Responsiveness Summary documents the comments received by EPA
Region IV during the public comment period regarding the proposed
cleanup alternatives described in the Proposed Plan Fact Sheet and
as presented at the public meeting held March 27, 1990. This
Responsiveness Summary provides the EPA with information about the
views of the Community and potentially responsible parties
regarding the proposed remedial action and alternatives. The
Responsiveness Summary documents how public comments have been
considered during the decision-making process and provides answers
and information to questions and issues raised. The Responsiveness
Summary becomes available to the public as part of the Record of
Decision (ROD) upon signature by the Agency.
The record of attendance, provided as Attachment D, lists 49
attendees including representatives from Harris Corporation,
General Development Utilities, Incorporated (GDU), Florida Audobon
Society, Turkey Creek Sanctuary Advisory Board, Florida Institute
of Technology, the Orlando Sentinel newspaper, South Brevard Water
Authority as well as city, county and state officials.
Attachment E contains the transcript of the public meeting. EPA and
Harris Corporation utilized overhead transparencies in the meeting
presentations to describe the site history, groundwater
contamination, and the existing Harris remediation program as well
as five additional remedial action alternatives. EPA provided
copies of the overheads and other information to meeting attendees.
Attachment F contains the meeting handouts.
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2.0 OVERVIEW OF THE PROPOSED PLAN
Of the six alternatives evaluated, EPA has determined that the
preferred alternative is Alternative 3, modification of the
existing groundwater extraction and treatment system. Alternative
3 compares favorably with the alternatives based on an evaluation
using the nine criteria mandated by the Superfund Amendments and
Reauthorization Act of 1986 (SARA). EPA defines Operable Unit One
as the groundwater contamination associated with the Government
Systems facility at Harris. EPA has further identified at least
one additional operable unit for management of response activities
at other portions of the site. Any additional operable units will
involve subsequent RODs.
This ROD presents Alternative 3 as the appropriate course of
remedial action for Operable Unit One at the Palm Bay site. This
remedy consists of (1) continued operation of the existing
extraction and treatment system, (2) a design analysis for plume
containment and treatment, (3) modification of the system based on
results of the design analysis, (4) continued monitoring of the
cleanup, and (5) a review of the system and cleanup progress by EPA
and FDER after a period of five years.
Based on comments received during the public comment period, the
residents and local officials are amenable to EPA-directed
modifications to the existing treatment system. However, one
resident stated specifically that he is against the use of deep
well reinjection. Citizens submitted ten response cards to EPA,
six at the conclusion of the public meeting and four during the
public comment period. In addition, EPA received five letters:
one letter presented at the public meeting by counsel for GDU and
four mailed in during the public comment period. Attachment G
contains all written comments from the public received during the
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public comment period. Attachment H contains the response
submitted by Harris Corporation, the potentially responsible party
(PRP). Attachment I provides GDU comments and responses received
by EPA.
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any potential threat to human health. FDER also identified
successful groundwater treatment methods being used by both Harris
and GDU. Other public concerns included surface water
contamination, especially if it should reach Turkey Creek, as well
as potential increases in water utility rates.
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4..0 SUMMARY OF COMMENTS RECEIVED AND AGENCY RESPONSE
Comments raised during the Harris Corporation/Palm Bay Facility
public comment period on the proposed plan are summarized briefly
below. The comment period was held from March 18, 1990 to April
17, 1990. All written public comments received by EPA are provided
as Attachment G. The comments are categorized by relevant topics.
4.1 Health Issues
1. Has a health risk analysis been performed at the site, and if
so, is it available to the public?
EPA Response: In October, 1988 the Florida Department of
Health and Rehabilitative Services (FDHRS) published a
preliminary Health Assessment prepared for the Agency for
Toxic Substances and Disease Registry (ATSDR). This report
states that "based on the existing condition of the Harris
Corporation site, the potential environmental pathways of
concern are migration of contaminated groundwater and
windblown volatile organic compounds from the air stripper.
Potential human exposure pathways of primary concern are
ingestion and dermal absorption of contaminated groundwater,
and inhalation of off-gassing volatiles from the air stripping
system.11
During pilot testing of the air stripping tower at Harris,
FDER analyzed projected air emissions. This analysis
indicated that the projected volume of emissions was not high
enough to present an unacceptable health risk. EPA performed
a similar analysis in February, 1990 using the FDER air
emissions criteria used for the pilot test on the 1988 and
1989 air stripper data from Harris. This analysis showed that
the air stripper emissions in 1988 and 1989 were within the
limits used by FDER for the projected emissions.
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Since the original FDER analysis, the exposure limits for many
of the volatile organic compounds have been reduced and newer
clean air regulations have been enacted by Florida and EPA.
EPA is currently analyzing the air stripper emissions using
the most recent Florida and EPA criteria and comparing the
results with health risks and the recently revised Clean Air
Act and FDER equivalents. EPA will require that the air
stripper emissions comply with the new requirements.
In order to address the remaining exposure pathway of
groundwater ingestion, EPA prepared a risk (or endangerment)
assessment based on the available groundwater sampling data.
This risk assessment, in the form of a memo, shows the results
of calculations for the risks associated with the consumption
of groundwater. These calculations indicate that drinking
untreated groundwater at Government Systems would constitute
an unacceptable human health risk. This memo as well as the
other EPA and ATSDR documents are available in the
Administrative Record for public review.
2. Do VOCs in groundwater percolate up through the soil - or
concrete, if there are cracks in the concrete?
EPA Response; According to ATSDR, it is possible for VOCs to
volatilize from the water table and migrate through the soil
and cracks in the concrete to reach the air above ground. The
VOCs migrating through the soil typically enter the air via
the soil/air interface or via cracks in the concrete in areas
where the soil is covered.
Some workers at the site have expressed concern about VOCs
entering the buildings. A National Institute of Occupational
Safety and Health (NIOSH) representative states that the
migration of VOCs through cracks in concrete and into the
buildings is unlikely to cause a health hazard at this site.
While it is possible for VOCs to enter the buildings, the
8
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health hazard would be minimized by the air exchange rate in
the buildings and the dilution of the VOCs by the existing
air in the buildings. Please see the response to Question 3
for more information.
3. Are there any risks at this site from breathing either indoor
or outdoor airborne contaminants?
EPA Response; FDER analyzed outdoor emission projections for
the air stripper which do not indicate that inhalation
presents a health-based risk at this site. Further, EPA
received the results from indoor air quality studies performed
in November, 1989 by NIOSH and concurrently by the Harris
Corporation Health and Safety Department. The detection
limits that NIOSH used are well below the levels established
by the Occupational Safety and Health Administration (OSHA)
as permissible for an eight hour occupational exposure. These
studies indicate that the indoor air in Building 8 on the
Harris facility is not contaminated with airborne volatile
organic compounds. In addition, the health symptoms reported
to NIOSH in a self-administered employee questionnaire "were
mostly respiratory and sinus complaints which could have been
the result of allergies, colds, or episodic respiratory
infections commonly experienced by any worker population."
4. Is it acceptable for people to be working at this site? What
are the risks, health effects, or possibility of one dying as a
result of working 10 or 20 years at this site in a location
directly above the area of highest concentration in the groundwater
plume?
EPA Response; Various studies and investigations have been
conducted at the site by FDER, USEPA, ATSDR, and NIOSH.
Neither the information available from these studies nor the
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scientific literature indicate that undue or significant
adverse health effects can be expected or have been observed
from exposure to the VOCs in the groundwater.
In addition, there is no information in the scientific or
medical literature that addresses the possibility of dying
from long term above-ground exposure to VOCs in groundwater.
Further comments on this issue would be conjecture.
5. Has any health monitoring for chemical toxicity symptoms in
workers been done at this site? If so, are these reports available
to the public? Will medical profiles be established for workers
at the site?
EPA Response; These are issues that are appropriately
directed to the Harris Corporation Health and Safety
Department. EPA contacted Harris and determined that certain
Harris employees undergo routine medical monitoring based on
the potentially hazardous nature of their jobs. However,
monitoring of other workers at the site would be initiated at
the request of an individual employee or Program Director, in
the case of a non-Harris employee. Harris reported that to
date there have been no individual requests for medical
surveillance.
6. Have local cancer rates been studied to see if there is a
correlation between chemical exposure at Harris and the incidence
of cancer?
EPA Response; EPA is not aware of any such studies. However,
the FDHRS maintains a cancer surveillance program on each
county in Florida. One can obtain further information from:
10
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Dr. Roger Inman, Chief
Toxicology and Hazard Assessment Section
Florida Department of Health and Rehabilitative Services
1317 Winewood Boulevard
Tallahassee, FL 32301
The telephone number is (904) 488-3931.
7. Have local health officials/professionals been given detailed
information about the location, type, and toxicity levels of the
chemical pollutants related to this site?
EPA Response; Information on chemical pollutants at this site
is publicly available in two ways. First, EPA established an
information repository on March 6, 1990 containing information
about the groundwater contamination associated with the
Government Systems facility. Second, the Emergency Planning
and Community Right-to-Know Act of 1986 (also known as Title
III) establishes requirements for federal, state, and local
governments and industry regarding emergency planning and
"community right-to-know" reporting on hazardous and toxic
chemicals.
OSHA requires companies to compile information on the identity
of hazardous chemicals used or produced including the health
and physical hazards as well as exposure limits for these
chemicals. This information is reported on Material Safety
Data Sheets (MSDSs).
Section 311 of the Emergency Planning and Community Right-to
Know Act (Act) requires facilities that must prepare MSDSs
under OSHA regulations to submit either copies of their MSDSs
or a list of MSDS chemicals to the local emergency planning
committee (LEPC), the state emergency response commission
11
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(SERC) , and the local fire department. If a list is
submitted, the facility.must submit a copy of the MSDS for any
chemical on the list at the request of the LEPC or SERC.
The LEPC for Brevard County, Florida is based in Winter Park
and the contact person is Leslie Banks who can be reached at
(407) 645-3339. The SERC is located in Tallahassee and is
comprised of members who are appointed by the governor to
oversee and implement Title III provisions. The contact
person for the SERC is Jim Loom is of the Department of
Community Affairs. He can be reached at (904) 488-1472.
If the facility submits a list of MSDS chemicals, the list
must include the chemical or common name of each substance and
must identify the applicable hazard categories. These
categories include among others, the immediate (acute) health
hazard and delayed (chronic) health hazard.
Section 313 of the Act requires EPA to establish an inventory
of routine toxic chemical emissions from certain manufacturing
facilities. These facilities must have more than ten full-
time employees and manufacture, process or otherwise use a
listed toxic chemical (from a list containing over 300
compounds) in excess of specified threshold quantities. For
example, facilities manufacturing or processing any of these
listed chemicals in excess of 50,000 pounds in 1988 were
required to report to EPA by July 1, 1989 their routine
releases to the environment. This information is maintained
in the Toxic Release Inventory System (TRIS) database as well
as TOXNET, a similar database that is accessible to the
public. EPA has confirmed that Harris reported routine toxic
chemical emissions under Section 313 for 1987 and 1988. This
information is available on request under the Freedom of
Information Act by contacting:
12
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Ms. Phyllis strong
Office of Public Affairs
U.S. Environmental Protection Agency
345 Courtland Street.N.E.
Atlanta, GA 30365
8. At what level is vinyl chloride or the other volatile organics
at the site toxic in air and water? At what concentrations can
these compounds be smelled?
EPA Response; The OSHA Permissible Exposure Limit for
airborne vinyl chloride (VC) in the workplace is 1 part per
million (ppm) over an eight hour period. In drinking water,
the health-based risk for VC is 0.02 parts per billion (ppb).
The odor threshold for VC in air is 260 ppm.
Exhibit 1 and the following discussion give more detailed
information about the toxic levels for VC and other VOCs in
air and water. For water, health-based risk levels can be
expressed as concentrations representing the lifetime
consumption level that would result in an additional increased
lifetime cancer risk of one in one million. For air, three
primary health-based risk levels are used to determine
acceptable exposures in the workplace. These levels are the
Threshold Limit Values (TLV) as determined by the American
Conference of Governmental Industrial Hygienists (ACGIH),
Permissible Exposure Limits (PEL) enforced by the Occupational
Safety and Health Administration (OSHA), and Recommended
Exposure Limits (REL) determined by NIOSH.
The TLVs as defined by the ACGIH refer to airborne
concentrations of substances and represents conditions under
which it is believed that nearly all workers may be repeatedly
exposed day after day without adverse effects. There are
three categories of TLVs which are specified as follows:
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Exhibit 1
EXPOSURE AND ODOR PARAMETERS FOR
VARIOUS VOLATILE ORGANIC COMPOUNDS
Acceptable
Volatile Organic Water
Compound Cone, (DPb)
Vinyl Chloride*
1, 1-Dichloroethane
Methylene Chloride*
Trichloroethylene*
Chlorobenzene
1, 2-Dichlorobenzene
1 , 2-Dichloroethylene
Ethyl Benzene
1, 1-Dichloroethylene*
Toluene
0.02a
0.4a
4.8a
3.2a
140
630
140
700
0.06a
Air
Exposure
Limits fppm)
lb
100b
500°
100d
75b.c
50b'9
200b'c
100b'c
lb
100b.c,d
Odor
Threshold
(coml
260 f
120 '
212 f
21 f
0.2f
0.39
1.0f
2.39
4.79
Notes;
* Human or suspected human carcinogen
a This concentration represents the lifetime groundwater
consumption level that would result in an additional increased
lifetime cancer risk of one in one million.
b PEL
c TLV
d REL
e TLV-C
f Source: American Society for Testing and Materials;
Publication DS-48A; Compilation of Odor and Taste Threshold
Values Data.
g Source: Amoore J.E. and Hautala E., 1983. Odor as an aid to
chemical safety: Odor thresholds compared with threshold
limit values and volatilities for 214 industrial chemicals in
air and water dilution; Journal of Applied Toxicology; 3:272-
290.
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a) Threshold Limit Value - Time-weighted Average (TLV-
TWA) - The time-weighted average concentration for
a normal 8-hour workday and a 40-hour work week to
which nearly all workers may be repeatedly exposed,
day after day, without adverse effects.
b) Threshold Limit Value - Short Term Exposure Limit
(TLV-STEL) - A 15 minute time-weighted average
exposure which should not be exceeded at any time
during a work day even if the 8-hour time-weighted
average is within the TLV. Exposures at the STEL
should not be longer than 15 minutes and should not
be repeated more than four times per day. There
should be at least 60 minutes between successive
exposures at the STEL.
c) Threshold Limit Value - Ceiling (TLV-C) - The
concentration that should not be exceeded during any
part of the working exposure.
9. Several people working on the site have expressed concern that
a very serious and unaddressed problem exists that is threatening
worker health. For example, a government employee working in
Building 8 on the Harris Government Systems facility is concerned
about an undiagnosed persistent cough she has experienced since
beginning work at the site in 1985. She explained that none of the
35 people in her office were informed that they work ten feet over
groundwater containing toxic wastes. Although she has not noticed
any VOC odors, she is concerned about VOCs percolating into the
building due to a groundvater to air media transfer and the
resulting potential adverse health effects.
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EPA Response: Air sampling conducted at Building 8 by NIOSH
and the Harris Health and Safety Department identified no
airborne contamination in the breathing zone. At this time
EPA has not performed a risk analysis for an air exposure
pathway.
Although he sees no cause for alarm, an ATSDR representative
has advised this employee to contact her management about
relocating to a different office space if necessary to
alleviate these concerns.
10. The same government employee filed a NIOSH complaint which
resulted in a NIOSH air quality study conducted by Mr. Stanley
Salisbury in November, 1989. The employee identified three
concerns about how the study was conducted:
A. Mr. Salisbury reportedly normally deals with air quality
issues relating to dust, spores, and bacteria rather than with
toxic waste.
B. NIOSH conducted the study during the cooler month of
November and, in addition, the air conditioning system which
had not been operating formerly was running during the test.
She believes that these factors may invalidate the test.
C. The results reported values in the parts per million
range and she is concerned about parts per billion exposure.
In addition, has any other air quality sampling been done in
Building 8 or elsewhere at the site?
EPA Response; The detection limits used by NIOSH were several
orders of magnitude below the OSHA Permissible Exposure Limits
for workers. Also, the existing occupational air exposure
standards for vinyl chloride, for example, is in the parts
per million range. Levels of vinyl chloride in the
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groundwater are reported in the parts per billion range and
therefore, would not likely result in any significant human
exposure.
EPA contacted Mr. Salisbury to address the above-mentioned
concerns about the study. He stated that he has had
significant experience with indoor air quality and measured
for "the six VOCs present in groundwater at concentrations in
excess of the current groundwater standards" according to the
established NIOSH protocol. He confirmed that the Harris
Health and Safety Department conducted concurrent air
monitoring during his visit. The Harris Health and Safety
Department's results were consistent with the NIOSH results
which indicated no measurable VOC airborne contamination.
EPA contacted Harris to determine whether or not any
additional indoor air monitoring has taken place. Harris
reported previous sampling for VOCs and carbon dioxide in
response to worker concerns about contamination from past
manufacturing operations in Building 6. This sampling is
consistent with the Harris policy in which the Health and
Safety Department conducts air monitoring on request for the
numerous buildings at the site.
«
11. Is the contaminated groundwater getting to GDU? If so, how
much contamination is the public receiving from the drinking water?
EPA Response: The contamination has reached some of the GDU
wells. At least one of the wells has been shut down and the
water from several other wells is being pre-treated for VOCs
using an air stripper. The water undergoing pre-treatment is
tested before and after air stripping. The VOC test results
after air stripping do not show VOCs to be present above the
detection limits (measured in parts per billion). In
addition, the finished water distributed to Palm Bay residents
is tested before distribution. The VOC test results for the
finished water do not show VOCs to be present above the
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detection limits (measured in parts per billion). Sampling
analyses indicate that the residents receive water from GDU
that meets drinking water standards.
In April, 1989 GDU had Target Compound List (TCL) analyses
performed on water samples from eight production wells before
pre-treatment and on one finished water sample. Pesticides,
PCBs, and semi-volatile organics were not present above the
detection limits (measured in parts per billion) in the
samples from the production wells. Several VOCs were detected
in the samples from the production wells, but were not present
above the detection limits in the finished water. Lead,
chromium, and zinc were present at low concentrations in
several of the production wells, but the levels were within
the primary and secondary drinking water standards.
The finished water sample analyses showed no contaminants
above the detection limits, except for several trihalo-
methanes, chromium, and zinc. The trihalomethanes, which are
common VOCs in finished water, were detected at low
concentrations but were within the total trihalomethane MCL
(100 ppb) for finished water. The chromium and zinc values
were below the primary maximum contaminant level (MCL) for
chromium (MCL is 50 ppb) and the secondary maximum contaminant
level (SMCL) for zinc (SMCL is 5000 ppb).
12. A resident asked why the air stripping tower contained no air
pollution control devices, and if anyone performing maintenance of
this air stripper would be in any danger from the emissions.
EPA Response; Before construction of this tower, FDER
analyzed the projected emissions based on the volume of
groundwater to be treated. FDER determined that based on an
eight-hour occupational exposure and 24-hour residential
exposure over a long period of time, the treatment system
design would present no significant short or long term risk.
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4.2 Technical Issues
1. Why does EPA want to modify the current treatment facilities?
Couldn't modification cause leakage between the aquifers from
further drilling or maintenance?
EPA Response; The current EPA cleanup goals are significantly
different from those identified in the FDER Consent Order.
Therefore, a treatment system that meets the criteria
specified in the order would not necessarily meet the EPA
criteria for cleanup of the aquifer. For example, vinyl
chloride and trichloroethylene now have more stringent cleanup
goals. These and the other EPA cleanup goals are specified in
the Record of Decision.
EPA and FDER will oversee a monitoring program to determine
when the aquifer has been remediated to an acceptable level so
that the treatment system is no longer required. A design
analysis will help determine system effectiveness and
efficiency as well as predicting the remediation time frame.
It is unlikely that modifications to the existing remediation
system would result in leakage between the aquifers. The
additional monitoring wells which are being considered would
be drilled using established methods that minimize the chance
of creating remedy-related leakage between the aquifers.
These drilling methods offer the ability to place casing in
the borehole at selected depths to effectively seal off one
aquifer froa another.
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EPA and FDER would review any proposed drilling, well
installation, or well completion procedures for compliance
with EPA-accepted procedures prior to drilling. EPA and FDER
would also check that procedures would not create leakage
between the aquifers in situations where several aquifers
would be dri-lled through or result in potentially contaminated
fluids inside the casing from one aquifer being introduced to
another aquifer. Deviations from accepted procedures would
be corrected prior to actual drilling. EPA and/or FDER
representatives would be present during drilling, well
installation, and well completion activities to confirm that
proper procedures had been followed.
In addition to the above precautions, unused monitor wells or
suspect monitor wells would be decommissioned to prevent them
from being or becoming potential conduits for downward or
upward migration of contaminants. Decommissioning would be
in accordance with recognized methods which prevent the
creation of vertical conduits between the aquifers by removing
the materials used to construct the decommissioned well and
sealing the decommissioned well borehole with an impermeable
grout.
The groundwater treatment system would continue to operate
during any decommissioning or additional drilling procedures.
2. Do volatile organics decompose on their own naturally? Do
they decompose to safer or more harmful components?
EPA Response; Some decompose to safer materials and
eventually to carbon dioxide (C02). Others decompose through
intermediary stages that become more toxic. The decomposition
of trichloroethylene (TCE) to vinyl chloride (VC), shown in
Exhibit 2, is an example of the organic degradation product
being more toxic than the original contaminant.
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Exhibit 2
Degradation Reaction of Trichloroethylene
1,1 DCE
TCE
TRANS 1,2 DCE
VINYL CHLORIDE
DCE - Dichloroethylene
Source: McKown. GO... G.W. Dowoon, and CJ. Engfeh, 1987. Critical
ElemcntB in Site Characterization. In: Ground-Water Monitoring
Seminar Seriee; Techncal Papere. U.S. EPA(CEFU-87-7)
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3. What was the Hazard Ranking System rating for Harris and how
does this compare with other sites?
EPA Response; The Hazard Ranking System (HRS) involves a
mathematical model which scores sites from 0 to 100,
indicating the probability and magnitude of risk to public
health and the environment. Any site with a score of 28.50
or higher is eligible for inclusion on the National Priorities
List (NPL), which would make available federal Superfund
monies for cleaning up the site as necessary. The highest
score received by a site is 75.60. The Harris site received
an HRS ranking of 35.52.
4. What is done with the contaminated waste that is eliminated
from the water at Harris?
EPA Response; VOCs in the groundwater are removed from the
water in an air stripping tower. The design of the tower
allows the volatiles to disperse into the air at a rate that
yielded an acceptable risk range for protection of human
health based upon the FDER projected emissions calculations.
The treated groundwater is used as process water in parts of
the' Harris manufacturing process. This process water is
subsequently discharged into a deep saline aquifer under a
permit from FDER.
5. Is Harris introducing new waste products into the aquifer or
has that been stopped?
EPA Response; EPA is not aware of any new contamination as
a result of the current operations at the site. However, a
comprehensive analysis .of potential source areas may identify
any ongoing, previously unidentified contamination areas.
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6. Can the water at the 40 foot zone migrate in directions other
than the southerly direction indicated by the water level contour
map?
EPA Response; In general, the groundwater flow direction may
be determined from water level contour maps by drawing lines
that inters'ect the water level elevation contours at right
angles. This indicates that the overall groundwater flow
direction at Harris is southerly in the 40 foot zone.
Localized deviations with more southeasterly or southwesterly
directions can occur in areas where the water level elevation
is irregular or where the distance between the water level
elevation contours is large relative to the difference in
water level elevation thereby creating a nearly flat gradient.
However, these localized deviations resume a southerly flow
direction within short distances.
7. How close are these contaminants to the surface and what is
the highest concentration found there?
EPA Response: Volatile organic contaminants are present in
the groundwater within 15 feet below the ground surface in
some areas of the Government Systems facility. The
contaminant concentrations measured in groundwater from SP-2
(located near Building 6 in the 15-foot zone) in December,
1986, are:
42 ppb 1,1-dichloroethane (DCA)
19 ppb chloroethane
1.7 ppb trans-l,2-dichloroethylene
1.5 ppb vinyl chloride
1.2 ppb trichloroethylene
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4.3 Air Quality
1. What is the possible interaction of volatile compounds with
other waste gases or airborne products from nearby sources and what
kind of effects does it have on the atmosphere?
EPA Response; EPA has not looked at local waste gas issues
since the primary risk being addressed by the Agency at this
time is groundwater. However, the State is involved in air
analyses at and around the site. EPA will continue to
coordinate any further analysis with the State. However,
during pilot testing of the air stripping tower at Harris,
FDER analyzed projected air emissions. This analysis
indicated that the projected emission volume would not be high
enough to present an unacceptable health risk.
2. What are the other waste gases that are being discharged from
Harris Corporation or any other industries in the area?
FDER Response; The FDER Air Section has collected some air
samples; specific information is available from Chuck Collins
at the FDER district office in Orlando. His telephone number
is (407) 894-7555.
3. Numerous residents have complained to City officials and
agencies about odors coming from or around the area of Harris
Corporation. Neither FDER nor the local fire department have been
able to identify the source. One resident mentioned that the smell
is heavy and sweetish. Others describe chlorine or aspirin-like
smells. The sweet, heavy odor occurs frequently after sundown,
sometimes until the early morning hours. This smell can be so
repulsive in the area where one resident lives west of Harris
Semiconductor that she does not go outside. She and others are now
concerned that the odor could be from the air stripper and would
like to know how to recognize the smell of volatile organic
compounds .
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EPA Response: EPA has been informed by the City of the
concerns of the odors and will continue to work with FDER who
is the agency addressing this concern. City officials have
informed EPA that this odor problem is recent. Since the air
stripper operation has been ongoing for several years, FDER
will also be investigating any new sources. Exhibit 1 (see
page 14) indicates the odor thresholds for various VOCs.
4.4 Water Treatment Issues
1. What is done with the sludge residue which remains after water
treatment processes at GDU?
GPU Response; Sludges from wastewater is treated with lime
and is trucked as mil-organite to farms for disposal on
pasture land. It has some fertilizer value to it and no heavy
metals. It is tested quarterly and meets the regulatory
requirements for that type of disposal.
2. What happens to water that is deep well injected?
EPA Response; Treated water is injected into a deep well in
a saline aquifer which is not potable or acceptable for
irrigation. This disposal method is currently operating under
an FDER underground injection permit. A consultant for Harris
Corporation indicated that the case depth of the well is 2000
feet and the aquifer is an open hole to 2500 feet. Monitoring
wells overlaying this zone have not detected any leakage from
the wells into other aquifers.
3. Members of the audience were aware that GDU had shut down a
well recently because of VOC contamination. One member of the
audience wanted to know how EPA can say that Harris wells are
successfully capturing contaminants from their site when a GDU well
has to be closed due to increased contaminants.
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EPA Response; The GDU well that was shut down about 4 months
ago was not part of the treatment system. However, none of
the GDU wells undergoing treatment contains volatile organics
which exceed the allowed maximum contaminant level (MCL) , even
before treatment.
The GDU well that was shut down is near the Harris Building
100, recently identified as an area of contamination. It is
not uncommon to find new areas of contamination or trace
contaminants during an investigation. EPA is addressing these
findings in a subsequent operable unit or as a part of the
system modification in this Record of Decision. GDU has a
program in place to assure that the public water supply is
tested and meets drinking water standards before it leaves the
plant.
4.5 Local Well Water Supply Issues
1. A resident living just west of the Harris site was concerned
about the circumstances under which groundwater would migrate from
Harris in a westerly direction and thereby be drawn into the
residential sprinkler system.
EPA Response; It is unlikely that groundwater would migrate
westward from the Harris site. Private wells used for
sprinkler systems will not significantly impact the southward
directional draw of groundwater which is created by the
extraordinarily large pumping rate required at the GDU
wellfield.
2. A residential subdivision east of Turkey Creek is not serviced
by GDU. A resident of this subdivision wanted to know the
possibility of contamination in their local wells, perhaps from
isolated contaminated groundwater pockets from years ago.
EPA Response; If there is concern about the water quality or
another potential source of contamination nearby, EPA suggests
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that the resident contact the local health department or FDER.
Without additional information regarding the local wells in
question, further discussion would be speculative.
3. Another resident is concerned about whether well surveys have
been done for residential wells near the Harris property. No one
knows how long contaminated groundwater may have been consumed by
residents, since the contamination was not found until 1981. The
plume location was first identified in 1984. The resident was
concerned that contaminated water supplies may have been consumed
unknowingly over a long period of time.
EPA Response; A well survey was done recently as part of an
investigation at the Semiconductor Complex on the Harris site.
without historical analytical and water well location data, it
is speculative to determine where and how much contamination
existed before 1981. However, historical contamination may
have originated at Radiation Corporation, which began
operations in 1960. Harris has placed monitor wells east of
the known plume area near residences to determine whether
groundwater contamination may be present. Sampling data from
these monitor wells have not shown evidence of contamination.
4.6 Soil Testing Issues
1. How has soil contamination been addressed?
EPA Response; Harris has conducted • investigations to
determine the impact of VOCs, metals, and acid extractable
organics at Government Systems as well as other areas of the
site. Soil samples at Government Systems were taken based on
the location of possible source areas identified by past
operating and handling practices. These sampling locations
are shown in Exhibit 3.
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Exhibit 3
Harris Corporation / Palm Bay Facility
Government Systems Soil Sample Locations
LICCNO
• SOL SAMPlf LOCATIONS
• . SUSPECTED POSSIBLE CHEMICAL SOUftCE LOCATION
Source: Geraghty & Miller, Inc. April 1989. File No. MF0769EP01.
28
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Soils found to contain VOCs were remediated by a process of
removal, spreading, and discing the soil in order to allow the
chemicals to volatilize. This remediation took place for
soils in the area of the old neutralization ditch and
treatment lagoons near the east side of Government Systems and
from an area along the location of the old stormwater drain
north of Building 6.
2. Were soil samples taken beneath the buildings? At what levels
were these contaminants found from the surface?
EPA Response; Numerous soil samples have been taken around
buildings at Government Systems and on one occasion samples
were taken by drilling holes into the floor of Building 6.
No VOCs were detected in soil samples taken in 1985 in and
around Building 6. However, some phenolic compounds (acid
extractable organics) were detected at low levels (1 ppm or
less) in eight samples collected from four locations at the
3-foot and 6-foot levels. In addition, several metals were
found with copper and lead being of greatest concern.
Fluoride was also reported in these soil samples. The maximum
levels of metals in these samples were 407 mg/kg copper, 38
mg/kg lead, and 94 mg/kg fluoride, all at the 6-foot level.
Subsequent soils analyses done in 1987 from three borings
around Building 6 showed phenolic compounds to be below the
detection limits. These samples were taken in intervals from
3 to 39 feet. Copper was found at a maximum of 37 mg/kg at
the 39-foot depth, and fluoride was found at maximum of 6
mg/kg at a depth of 5 feet.
4.7 Water Utility Costs and Services Issues
1. One citizen expressed concern that he is paying for the cost
of water treatment in his monthly utility bill.
EPA Response; Harris Corporation has been responsible for the
costs associated with the groundwater treatment system on the
29
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Harris property as well as the costs for constructing,
maintaining, and monitoring of the air stripping tower at GDU.
4.8 Harris Corporation Comment
Harris Corporation submitted a letter during the public comment
period identifying questions and concerns about the EPA preferred
alternative. The letter and attached report are provided as
Attachment H.
1. This letter stated the Harris position that "the issues of
chemical source areas and metals in the soils and groundwater have
been adequately addressed" and that "no additional work on soils
removal or metal characterization is necessary."
EPA Response; EPA has reviewed the Harris comment letter and
report entitled "Summary of Soils Investigation and Metals in
Groundwater". Despite Harris1 assertion that "This report
indicates metals are not an issue of concern at the site,
there are no existing sources of chemicals remaining in the
soils and sediments, and no additional work on soils removal
or metal characterization is necessary.", metals in the soil
and groundwater are a concern. The report is not sufficient
to address this issue. Soil remedial levels based upon
analytical methods with which we are unfamiliar may not be
sufficiently protective of groundwater quality and therefore
may not support the remedial action taken by Harris. As a
result, additional soil/source characterization may be
necessary at the Harris site.
Hydroxide sludges were reportedly observed in the
Neutralization Lagoon, but metal analyses were not performed.
EPA has not located a discussion of what became of the
hydroxide sludges, which are sources for metals. In addition,
the groundwater monitoring program for metals has been
inconsistent; not all wells have been analyzed for metals.
The wells which have undergone metals analyses show an
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irregular sampling frequency. Many wells listed in the tables
were only sampled once, typically in the fourth quarter of
1986. The irregular sampling frequency makes it difficult to
determine the nature of the contamination and the behavior of
contaminants over time. Thus, it is not possible to conclude
that metals- are not an issue of concern. Also, the existing
treatment system (air stripping) does not remove metals from
groundwater.
There are instances where EPA contaminant-specific cleanup
goals were exceeded, but subsequent sampling was not
performed. For example, there was no subsequent sampling in
well SC-17S where lead was found at 140 parts per billion in
February, 1988. The EPA health-based cleanup level for lead
is 5 parts per billion. In addition, there are many cases
where the detection limit exceeded the EPA cleanup standard
for the contaminant, but subsequent sampling was not performed
to attain a detection limit below the cleanup standard.
2. The Harris comment letter states that "the existing recovery
system is not only reducing the concentration of chemicals in the
groundwater, but also effectively capturing the plume and
effectively remediating the aquifer." Therefore, no modification
to the existing system is necessary.
EPA Response; EPA has not yet reviewed the groundwater
modeling program conducted by Geraghty & Miller on the
existing Harris recovery system. However, this recovery
system was designed to meet the requirements specified in an
administrative order on consent with FDER. The current EPA
cleanup criteria for the aquifer are more stringent, in some
cases, than those identified in the order. Also, the plumes
have been defined by an aggregate value for VOCs rather than
by values for individual contaminants. Therefore, it is
uncertain whether or not the existing recovery system is
effectively capturing the plumes and thus preventing
contaminants from escaping the recovery system. As a result,
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EPA must first verify through a comprehensive site groundwater
evaluation what modifications are necessary and then determine
the specific modifications required to optimize the system for
treatment of the aquifer.
Until this comprehensive evaluation occurs, it is uncertain
what modifications will be required. The modifications may
involve a different groundwater recovery system, i.e.
installation of additional recovery wells or discontinued use
of existing wells. In addition, the sampling regime may be
modified to verify that the system is meeting EPA cleanup
criteria. Monitoring wells in potential source areas may be
sealed (or decommissioned), if necessary, to prevent the
downward migration of contamination from the surface.
Similarly, EPA will make an independent determination of
whether or not the wells "were constructed in a fashion that
seals the zones of the aquifer from interconnecting."
3. Harris "questions the premise that air emissions from the air
stripping tower may require additional testing."
EPA Response; Testing of the air emissions from the air
stripper will be required to demonstrate compliance with
applicable air cleanup standards. The EPA Air, Pesticides and
Toxics Management Division states that the air stripper
technology will comply with the cleanup standards, but this
does not relieve Harris of its responsibility to demonstrate
that the air emissions .and effluents are in compliance with
federal and Florida air quality standards.
4. Harris states that "additional analysis of wells outside the
identified plume areas is unnecessary" because of the extensive
sampling conducted to date.
EPA Response: EPA confirms that an extensive amount of
sampling data has been collected at the site. However, the
sampling regime was not systematic in some cases. As a
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result, it is difficult to get a comprehensive view of the
contamination at the site. In addition, containment of plumes
will ultimately be determined by the regular sampling of
monitor wells outside the plume areas.
5. The Harris, comment letter states the Government Systems
groundwater remediation system is not an interim measure, but was
designed as the "final remedial alternative for the identified
plumes of chemicals" under the Government Systems facility.
EPA Response; EPA policy on the extraction and treatment of
contaminated groundwater considers recent evidence suggesting
that it may be more difficult than is often estimated to
achieve cleanup concentration goals in groundwater. The
policy recommends an approach involving the initiation of
early action while gathering more detailed data prior to
committing to full-scale restoration. This recommendation
encourages the collection of data to allow for the design of
an efficient cleanup approach that more accurately estimates
the time frames required for achieving the groundwater cleanup
goals. Early action proves valuable in preventing the
contaminant plume from spreading while the investigation to
optimize the remediation system progresses.
6. The Harris letter states that "should GOU choose unilaterally
to significantly modify its groundwater withdrawal scheme, this
will directly impact the ability of the Harris remedial system to
control the plume in the lower surficial aquifer."
EPA Response; Due to the long-term nature of the cleanup
process, the Harris remediation system must be able to
function independently of GDU groundwater withdrawals. The
remedial system should be designed such that it can take
advantage of GDU's withdrawals and the predictable impacts on
the groundwater flow, as well as contaminant transport. The
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remedial system should also be demonstrated to be adaptable
and responsive to modifications in GDU's groundwateJ
withdrawal scheme.
7. The letter states that "it is not necessary or appropriate for
water from the treatment system to meet potable water standards"
because the treated water is used strictly for industrial purposes.
*
EJPA Response: The treatment standards for disposing treated
groundwater depend upon the intended disposal method. If
treated groundwater is to be used for human consumption or
returned to the aquifer via percolation ponds or reinjection
wells, the drinking water quality standards are the treatment
criteria.
This Record of Decision selects a disposal option involving
the use of permitted underground injection wells or, as an
alternate, surface water discharge. In either case, the
treated water must meet permit requirements; the Underground
Injection Control (UIC) permit for deep well injection and the
National Pollutant Discharge Elimination System (NPDES) permit
for surface water discharge. These permits specify the levels
to which the groundwater must be treated before disposal. For
example, before disposal into the UIC permitted wells, the
treated groundwater must not contain hazardous waste.
Regional guidance states that EPA considers that the
groundwater no longer contains hazardous waste once it has
been treated to health-based levels.
8. EPA has reviewed the report that accompanied the comment
letter. This report recaps data collected between 1986 through
March 1989 which has been presented in previous reports.
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EPA Response; The statement that "Sufficient data are
available to assess the level of metals in groundwater at
different depths across the site." is inaccurate. Most of the
monitoring wells on the site have not been analyzed recently
for metals.- Given this, it is not possible to conclude that
"metal levels in the groundwater do not currently exceed
MCLS...
The data included in the report shows that groundwater cleanup
goals for metals are exceeded (or are potentially exceeded)
in several instances. In twelve wells sampled in 1987, a
detection limit of 50 parts per billion (ppb) was reported for
cadmium. The Maximum Contaminant Level (MCL) is 10 ppb.
Therefore, we do not know if these wells are contaminated to
a level that exceeds the MCL. These wells have not been
resampled. Two wells had positive results for cadmium, one
above and one below the MCL.
Chromium concentrations have been recorded at levels well
above the MCL of 50 parts per billion in numerous wells.
Although the more recent sampling results do not show elevated
levels of chromium in these wells, the likely explanation for
this phenomenon is that the contaminant plume has moved away
from these wells over the' intervening three year period. This
situation illustrates the need to more completely characterize
the nature and extent of groundwater contamination at the
site.
At least five wells have shown levels of lead above the MCL
of 50 ppb, and numerous others have been shown to be
contaminated above the health-based cleanup level of 5 ppb.
The frequency of positive detections has decreased over time.
However, it is uncertain to what locations these metals have
migrated in the groundwater. In addition, the assumption that
the lead concentration in SC-17S is anomalous is
inappropriate. An appropriate procedure would be to perform
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subsequent sampling to confirm either that the value is
anomalous or that lead is present in the groundwater.
The hydroxide sludges in the old Neutralization Lagoon (now
under Building 5) were not chemically characterized for
metals. EPA has not received documentation for what became
of these sludges. Whether or not the hydroxide sludges and
underlying soils would have required remediation is not known.
As a result, the area around Building 5 remains a potential
source area.
Based upon the data presented in the report, it is not
possible to conclude that "metals are not present in
groundwater... at levels that warrant remediation." The
above-mentioned examples indicate that the metals
contamination at the site is not well-defined and potentially
significant. If Harris has additional data which has been
used to reach their conclusion, the data or studies should be
made available to EPA for analysis.
4.9 General Development Utilities Comment
GDU submitted two letters during the public comment period
identifying concerns about EPA actions and the preferred remedial
alternative at the Harris Corporation site. These letters are
presented in Attachment I.
1. The GDU letter poses the question of whether the cleanup
standards will be the current EPA standards and not those standards
identified in the Consent Order between FDER and Harris.
EPA Response? The cleanup standards identified in the EPA
Record of Decision for Operable Unit One of the Harris site
are based on the contaminant levels necessary to restore
beneficial use of the aquifer. Three of these cleanup levels
(trichloroethylene, vinyl chloride, and methylene chloride)
are more stringent than those identified in the 1983
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FDER/Harris Consent Order. These aquifer cleanup levels are
obtained from a number of sources as appropriate for each
contaminant. These sources are: the current State of Florida
Maximum Contaminant Levels (MCLs), health-based criteria for
a one in one million excess cancer risk level, the cleanup
criteria identified in the 1983 FDER/Harris Consent Order, and
Secondary MCLs.
2. The GDU letter expresses concern that a temporary shut-down of
the Harris remediation system will accelerate migration of the
contaminant plume and affect GDU wells.
EPA Response; Such a shut-down would be initiated only after
contaminant levels in the aquifer had reached or was below the
cleanup goals specified in the ROD and had reached an
asymptotic level below which no decrease occurred over a
significant period of time. In this case, a temporary
shut-down of the extraction system concurrent with careful
monitoring of the groundwater would allow us to determine
whether or not the sources of contamination had been removed.
3. It is unclear how the monitoring program identified in the ROD
will be implemented.
EPA Response; The existing monitoring program will be
modified as necessary to fully characterize the extent of
contamination at the site. A monitoring program will continue
for an estimated three years or until the cleanup goals are
met. Following the onset of the EPA specified remedial action
(Alternative 3), EPA will conduct a review of the site to
verify that the aquifer has been restored to beneficial use.
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4. GDU is concerned that the Harris remediation system is
dependent upon the GDU water supply wells.
EPA Response: As described earlier, due to the long-term
nature of the cleanup process, the Harris remediation system
must be abl-e to function independently of GDU groundwater
withdrawals. The remedial system may be able to take
advantage of GDU's withdrawals and any predictable impacts on
the groundwater flow. The remedial system should also be
adaptable and responsive to modifications in GDU's groundwater
withdrawal scheme.
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5.0 REMAINING PUBLIC CONCERNS
Issues and concerns which EPA was unable to address during remedial
planning activities for Operable Unit One, groundwater remediation
at the Government Systems Complex, included the following:
o Specifying the modifications to be made to the existing
groundwater extraction and treatment system.
o Request for EPA to thoroughly review the issues raised at the
public meeting and to advise the public of anticipated actions
in a follow-up meeting.
Specific modifications to the treatment system will not be
available until a design analysis is conducted for the treatment
system. EPA will release this information as soon as it is
available.
Additional operable units may be designed for groundwater cleanup
at other portions of the Harris facility, e.g., the Semiconductor
Complex and Building 100. Another potential operable unit is
source control or soil cleanup of discrete sources at the facility.
The public will be notified of ongoing investigations and findings
as well as opportunities for public participation.
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