United States . Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-92/116
September 1992
vxEPA Superfund
Record of Decision:
Standard Auto Bumper, FL
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NOTICE
The appendices listed in the index that are not found in this document have been removed at the request of
the issuing agency. They contain material which supplement but adds no further applicable information to
the content of the document All supplemental material is, however, contained in the administrative record
for this site.
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50272-101
REPORT DOCUMENTATION 1. REPORT NO. 2.
PAGE EPA/ROD/R04-92/116
4. TMeendSUbWe
SUPERFUND RECORD OF DECISION
Standard Auto Bumper, FL
First Remedial Action - Subsequent to follow
7. AUharM
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
1* fwctpiwii • AccMSMOfi No.
«. Report (Me
09/28/92
«.
«. Performing OroantartonBept. No.
11. CoMnd(C) or «eM(a) No,
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EPA/ROD/R04-92/116
Standard Auto Bumper, FL
First Remedial Action - Subsequent to follow
Abstract (Continued)
1989 and 1990, a removal action included soil excavation of the discharge trench area and
offsite disposal of the material. The primary source of contamination was determined to
be the electroplating process waste streams. This ROD addresses onsite contaminated soil
to reduce the migration of these contaminants to the ground water. Remediation of
contaminated ground water will be addressed in a subsequent ROD. The primary
contaminants of concern affecting the soil are metals, including chromium and lead.
The selected remedial action for this site includes excavating 2,500 cubic yards of
contaminated soil with concentrations exceeding a 10-6 risk level and disposing of the
soil offsite; backfilling the excavated areas with clean fill; and monitoring ground
water. The estimated present worth cost for this remedial action is $338,186, which
includes a present worth O&M cost of $40,186.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific soil clean-up goals are based on the
exceedance of a 10~6 risk level, including hexavalent chromium 52 mg/kg, nickel
370 mg/kg, and total chromium 519 mg/kg.
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respectively.
No excavation will take place below the water table. Current
knowledge of contaminants in the soil and groundwater indicate
that no excavation below the water table will be necessary.
In addition, aquifer characteristics indicate that dewatering
would not be feasible at this site.
• Offsite disposal of excavated soils at a Florida Class I
Landfill.
• Groundwater monitoring for up to 5 years.
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)
technology to the maximum extent practicable for this site.
However, because treatment of the principal threats of the site was
not found to be practical, this remedy does not satisfy the
statutory preference for treatment as a principal element.
Because this remedy will not result in .hazardous substances
remaining onsite above health-based levels, the five-year review
will not apply to this action.
Date / jUGreer C. Tidwell
* Regional Administrator
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DECLARATION STATEMENT
RECORD OF DECISION - OPERABT.g TIMTT ONE
STANDARD AUTO BUMPER SITE
Site Name and Location
Standard Auto Bumper Site
Hialeah, Dade County, Florida
Statement of Basis and Purpose
This decision document presents the selected remedial action for
the Standard Auto Bumper site, in Hialeah, Dade County, Florida,
which was chosen in accordance with the requirements of 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 Substance Pollution Contingency
Plan. This decision is based on the administrative record for this
site. The State of Florida, as represented by the Florida
Department of Environmental Regulation (FDER), has been the support
agency during the Remedial Investigation and Feasibility Study
process for the Standard Auto Bumper site. In accordance with 40
CFR 300.430, as the support agency, FDER has provided input during
this process. Based upon comments received from FDER, it is
expected that concurrence will be forthcoming; however, a formal
letter of concurrence has not yet been received.
Assessment of the Site
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in the Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
Description of the Selected Remedy
The response action described in this document represents the first
of two planned operable units for the site. This remedy addresses
the source of contamination, the soils. A prior removal action in
1989 entailed the removal of contaminated waste from an underground
trench and contaminated soils surrounding the Standard Auto Bumper
facility. Remaining contaminated soils are the existing threat at
the site. The second operable unit will address groundwater.
The major components of the selected remedy include the following:
• Excavation of approximately 2500 cubic yards of soils
contaminated with nickel, total chromium, or hexavalent
chromium equal to or exceeding 370 ppm, 519 ppm, or 52 ppm,
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TABLE OF CONTENTS
SECTION TOPIC
THE DECISION SUMMARY
1.0 Site Description 1
1.1 Surface Features 1
2.0 Site History 5
3.0 Community Relations Activities and Participation 7
4.0 Scope and Role of Operable Unit One 8
5.0 Site Characteristics 8
5.1 Surface Water Hydrology 8
5.2 Geology 9
5.3 Hydrogeology 10
5.4 Subsurface Features 12
5.5 Sampling Results 12
5.5.1 Surface Soil 13
5.5.2 Subsurface Soil 13
5.5.3 Groundwater 15
5.5.4 Surface Water and Sediments 24
6.0 Summary of Site Risks 24
6.1 Chemicals of Concern 24
6.2 Exposure Assessment 26
6.3 Toxicity Assessment 27
6.4 Characterization of Risk 29
6.5 Environmental Risks 33
7.0 Remediation Goals 33
8.0 Description of Alternatives 37
8.1 Alternative 1 - No Action 37
8.2 Alternative 2 - Excavation and Offsite Disposal 37
8.3 Alternative 3 - Excavation, Onsite Soil Washing,
and Onsite Replacement 38
8.4 Alternative 4 - Excavation, Stabilization/
Solidification, and Onsite Disposal 41
9.0 Summary of Comparative Analysis of Alternatives 43
10.0 Selected Remedy 48
11.0 Statutory Determinations 50
12.0 Documentation of Significant Changes 52
Appendix A Responsiveness Summary
Appendix B Risk Assessment Exposure Assumptions and Parameters
Appendix C DERM Soil Disposal Criteria
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LIST OF TABLES
NUMBER TABLE PAGE
1 Soil Sampling Data Summary 16
2 Toxicity Characteristic Leaching Procedure Levels 18
3 Contaminant Data for the Standard Auto Bumper Site 26
4 Intake Factors 28
5 Carcinogenic Toxicity Values for
Contaminants of Concern in Surface Soil 30
6 Noncarcinogenic Toxicity Values for
Contaminants of Concern in Surface Soil 31
7 Hazard Indices for Nonearcinogens in Surface Soil 32
8 Carcinogenic Risk Levels for Surface Soils 34
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LIST OF FIGURES
NUMBER FIGURE PAGE
1 Dade County Location Hap 2
2 Topographic Location Map - 3
3 Site Base Map 4
4 Shallow Aquifers in Southern Florida 11
5 Concentrations of Selected Inorganic Analytes
Detected in Surface Soil During the
Phase I RI 14
6 Concentrations of Selected Inorganic Analytes
Detected in Subsurface Soil
During the Phase 1 RI 17
7 Concentrations of Selected Inorganic Analytes
Detected in Groundwater, April 1991 19
8 Concentrations of Selected Inorganic Analytes
Detected in Groundwater From
Temporary Monitoring Wells
During the Phase 1 RI 21
9 Concentrations of Selected Inorganic Analytes
Detected in Groundwater From
Permanent Monitoring Wells
During the Phase 1 RI 22
10 Concentrations of Selected Inorganic Analytes
Detected in Groundwater From
Permanent Monitoring Wells
During the Phase 2 RI 23
11 Soil Above Cleanup Goals 39
12 Soil Washing System 40
13 Stabilization/Solidification 42
iii
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DECISION SUMMARY
1.0 SITE DESCRIPTION
The Standard Auto Bumper site is located in an industrialized area
of northeast Dade County, Florida at 2500 West 3rd Court,
approximately six miles northwest of downtown Miami and includes
areas where the contamination has come to be located (Figure 1).
Standard Auto Bumper is an active chromium and nickel plating
facility which has operated at the same Hialeah address since 1959.
The property area is approximately 42,000 square feet and
geographically located at 25°50'40" N latitude, 80°17'15" W
longitude. The site is shown in Figure 2 on the Hialeah, Florida
USGS 7.5 minute topographic quadrangle map.
Standard Auto is bordered on the north by Quality Manufacturing
Products, Inc. and World Metals; on the east, across West 3rd Court
by Nela Junk Yard; on the south by Fernandez Transport Corporation;
and on the west, across the railroad track, by the Gilda Bakery
(Figure 3). The Red Road Canal is located approximately 300 feet
west of the site running parallel to West 3rd Court and the
railroad.
Hialeah is an incorporated city that consists of heavy development
with mixed zoning. The city has an approximate population of
188,000 people and a strong manufacturing, wholesale, service and
retail industry. Twenty percent of .the property within a mile
radius of the site is utilized for commercial and industrial
purposes, sixty percent is residential, and the .remaining 20
percent is used for recreational parks and schools. It is
estimated that 11,000 people live or work within a mile radius of
the site.
1.1 Surface Features
The ground surface at the Standard Auto Bumper site is almost
entirely flat and unpaved, ranging between 6.5 feet and 9.5 feet
above the National Geodetic Vertical Datum of 1929 (NGVD29). The
ground surface elevation on-site is between 7.5 feet above NGVD29
on the southern part of the site and 6.8 feet above NGVD29 on the
northern portion of the site. The ground surface elevation on the
neighboring property to the west is between 9.0 and 9.5 feet above
NGVD29 and the ground surface elevation across West 3rd Court is
approximately 6.7 feet above NGVD29.
The area north of the facility building has two open excavations
where removal activities of contaminated soil occurred in 1989.
The open excavations are deeper on the westernmost sides and are
approximately 2.5 to 3 feet in depth. The site features consist of
a one story concrete block structure (approximately 19,150 square
feet), two concrete holding tanks, a concrete and an asphalt slab
and numerous holding and drying racks for bumpers and other chrome
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&EPA
DADE COUNTY LOCATION MAI
STANDARD AUTO BUMP!1
HIALEAH, FLORIDA
Figure 1
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1 S IV-
STANDARD AUTO 3UMPER SITE
APPROXIMATE SCALE
2000 0 1000 2000
t
15
Figure 2
TOPOGRAPHIC LOCATION MAP
-jtERA
( IN FEET )
1 incn - 2000ft.
^lAINUMKU AUIU DU.V.ri.-
HI ALE AH, FLCRiCA
SOURCE: USCS MIAL£A*. H-CXCO*
7.s MNuir sones OJAMAMCLE. -:M
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GRAPHIC SCALE
0 90
SITE BASE MAP
STANDARD AUTO BUMPER /
HIALEAH. FLORIDA
y*y kU^ SQURC& U & tft* V
MUM. PHOTO Ijjo/ft. tMfll
IflCATtD MXAHM ID
MUMUMT sumrr oi/n/n
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items. Other one story concrete block structures housing
commercial/industrial businesses occupy the immediate surrounding
area.
The Red Road canal is the nearest body of surface water to the site
and is located to the west at a distance of approximately 300 feet.
Based on the elevations obtained from the vertical control survey
conducted during the RIf the Florida East Coast Railway (FEC)
roadbed acts as an artificial dike that prevents any westward
migration of surface water from the site.
2.0 SITE HISTORY
Standard Auto Bumper Corporation has owned the electroplating
portion of the site since 1959. Prior to 1959, this property was
divided into 2 facilities: located on the southern half of the
site was a slaughterhouse, and on the northern half of the property
was a furnace/smelting company (Yacco, 1991). In 1959 Standard
Auto Bumper began chromium and nickel plating operations on the
site. Prior to installation of a treatment system in 1972, the
wastewater from Standard Auto Bumper's electroplating and stripping
process was discharged to a drainage ditch/swale area west of the
facility. Since 1972, a wastewater treatment system to convert
hexavalent chromium to insoluble trivalent chromium has been
operational. Approximately 5,760 gallons of wastewater per day can
be processed, according to Standard Auto Bumper. Between 1972 and
1979 the effluent from the treatment system was discharged to an
underground, slab-covered drainage trench located adjacent to the
treatment tanks. In 1979, use of this trench was discontinued when
the Hialeah sewer system became the receptor for the effluent
discharge. Numerous improper discharges of treated and untreated
wastes to the ground have been documented by Dade County
authorities.
A Metropolitan Dade County Department of Environmental Resources
Management (DERM) inspector observed effluent being discharged to
a soakage trench in the back alley on May 10, 1977. The owner was
ordered to correct the violations. However, on November 16, 1981,
a county inspector observed that metal cleaning waste was being
discharged into an on-site drain. On June 4, 1982, open and
leaking drums and discharges of plating liquids were found on the
ground. A pipe was also discovered leading from the facility into
a ditch and the ditch water sample contained 160 mg/1 of nickel,
160 mg/1 of chromium, and 7.52 mg/1 of copper.
A county Waste Dumping Citation was also issued to the facility on
June 4, 1982, and subsequent inspections found the facility had not
ceased illegal discharges. A Final Notice of Violation was issued
on October 5, 1983. A county inspector, on March 3, 1985, observed
evidence of untreated wastewater discharges into the city sewer
system.
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On August 14, 1985 soil and groundwater samples collected onsite by
the EPA contained numerous contaminants associated with metal
plating activities. On December 3, 1985, waste samples collected
by county officials contained concentrations of total cadmium and
nickel which exceeded county groundwater quality standards. On
September 10, 1986, county officials observed illegal discharges
and an overflow pipe leading offsite.
An Expanded Site Investigation (ESI) was conducted at the Standard
Auto Bumper site in March 1987, by the U.S. EPA Region IV Field
Investigation Team (FIT). Numerous soil and groundwater samples
were collected at the site as part of the ESI, and were used to
document the Hazard Ranking System (HRS) package data and provide
preliminary data for the Remedial Investigation/Feasibility Study
(RI/FS).
The ESI samples were analyzed for the parameters in the Hazardous
Substance List. This list, which was a precursor to the Target
Compound List and Target Analyte List, included organic and
inorganic chemicals. Elevated concentrations of heavy metals were
found in the former disposal areas and other areas of interest.
Similar contaminants were identified in the soils, groundwater, and
waste effluent samples, indicating that the source of groundwater
contamination is soil leachate from the discharge areas. The
detected organic compounds included polynuclear aromatic
hydrocarbons (FAHs) and pesticides. PAHs are associated with
creosote products that can be found in railroad ties and asphalt
paving. Pesticides are not related to the electroplating process
and were not attributed to the Standard Auto site. No groundwater
samples contained concentrations of any organic compounds above
Federal or State drinking water standards. The Standard Auto
Bumper site was proposed for inclusion to the National Priority
List (NPL) in June, 1988 and became finalized in October, 1989,
based on the HRS Package (1987).
In 1989 and 1990, Standard Auto Bumper conducted a soil removal on
the property under an Administrative Order (AO) with the EPA.
Under the removal action the PRP was required to excavate the soil
and sludge in the bottom of the slab-covered trench. The excavated
material was sent to the Chemical Waste Management facility in
Emelle, Alabama for disposal. Soils were also excavated from the
drainage ditch and south areas of the site to a depth of
approximately 6 feet. These soils were not deemed hazardous waste
and were sent to the South Bade County Landfill. The PRP's removal
activities were conducted under the oversight of the EPA.
The AO for the removal specified soil clean-up levels based on the
Extraction Procedure (EP) Toxicity test method for the contaminants
at the site. The extraction levels included cadmium at 0.01 mg/kg,
chromium at 0.05 mg/kg, copper at 0.4 mg/kg, lead at 0.05 mg/kg,
nickel at 0.15 mg/kg, and cyanide at nondetectable levels.
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On February 28, 1990, a second Administrative Order was signed
between Standard Auto Bumper and EPA to implement the RI/FS.
However, in February 1991, Standard Auto Bumper elected not to
continue performing the RI/FS, and EPA, Region IV, took over the
RI/FS activities. Standard Auto Bumper had not conducted any field
studies at the time EPA took over the remedial activities.
The EPA conducted the preliminary RI in April, 1991. Groundwater
samples were collected from existing monitoring wells at the site
to determine the current conditions of the groundwater. In
addition, sediment samples were collected from the Red Road Canal
to provide information on the site's impact on the canal.
The first phase of the RI took place in 1991 and 1992 and consisted
of the majority of the field activities (soil sampling, surface
water sampling, monitoring well installation, and additional ground
water sampling). Metals such as chromium, nickel, and lead were
found in the samples. During Phase 2 in May 1992, two additional
monitoring wells were installed and the third round of ground water
samples were collected from all of the wells. Analytical data
indicated that, between successive groundwater sampling events,
metal concentrations in the groundwater decreased considerably. A
significant portion of the apparent decrease, however, may be
attributed to improved, state-of-the-art, sampling techniques that
have been able to effectively eliminate turbidity.
EPA completed a Baseline Risk Assessment for the site in July 1992.
The assessment evaluated the current and potential future risks
posed by the contamination at the site under the no-action scenario
for current and future uses of the site. The Feasibility Study
(FS) Report was prepared by the EPA and finalized in August 1992.
The report evaluated a range of remedial alternatives that could
address the contaminated soil at the site. The alternatives
included no-action, removal, and treatment.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Prior to the RI/FS the EPA conducted an Information Availability
session to introduce the Super fund process and the site to the
community, explain the activities planned for the site, and answer
any questions. The meeting, held on January 10, 1991 in a local
school, was publicized in local papers and by door to door
canvassing in the community. At the completion of the RI/FS, the
RI/FS Report and Proposed Plan for the site were released to the
public in August 1992. These documents were made available to the
public in both the Administrative Record and an information
repository maintained at the EPA Records Center in Region IV and
the John F. Kennedy Memorial Library in Hialeah. The notice of
availability for the documents was published in the Miami Herald on
August 13, 1992, and the Spanish newspaper, Diario Las Americas, on
August 7, 1992.
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The Proposed Plan was sent to over 400 people in the community,
government, and media. A public comment period was held from
August 7 to September 6, 1992. A public meeting, announced in the
public notices and in the Proposed Plan, was held in a nearby
school auditorium on August 18, 1992. The purpose of the meeting
was to present the proposed plan and answer questions. Three
citizens attended the public meeting. A response to the comments
received during this period is included in the Responsiveness
Summary, which is part of this Record of Decision (Appendix A).
This decision document presents the selected remedial action for
operable unit one of the Standard Auto Bumper Superfund Site, chose
in accordance with CERCLA, as amended by SARA. The decision for
this site is based on the Administrative Record.
4.0 SCOPE AND ROLE OF OPERABLE UNIT ONE
As with many Superfund sites, studying and addressing contaminated
media in the most efficient manner can be a difficult endeavor, due
to complex characteristics of each site. As a result, EPA
organized the site into two operable units (OUs): one to address
contaminant source areas (OU #1) and the other to evaluate
groundwater conditions (OU #2). The remedy presented in this ROD
addresses the first operable unit, the contaminated soils at the
site.
This soil poses a principal threat to human health and the
environment due to ingestion of contaminated surface soils by
children of potential future residents and the soil contamination's
impact on the groundwater. The cleanup objectives for this OU are
to prevent current or future exposure to the soil contaminated with
nickel and chromium through treatment and/or containment, and to
reduce the migration of these contaminants from the soil to
groundwater.
The second operable unit will address the groundwater while the
remedial action presented in this ROD is performed. Additional
groundwater sampling will be necessary befere a final decision can
be made about the need for and type of cleanup alternative for this
media. A decision regarding OU f2 will be presented in a
subsequent ROD.
5.0 SITE CHARACTERISTICS
5«1 Surface Water Hv*^Toloqv
The location of surface water in Dade County is almost completely
limited to the intricate canal network that was dug to support
farming, flood control and urbanization. Drainage from the site
during rainfall events appears unlikely due to the topographic high
of the limestone gravel roadbed of the Florida East Coast Railway,
which acts as a barrier and the porous nature of the well drained
8
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sandy soils in the area. Surface water in the canals is in direct
hydraulic connection with the Biscayne Aquifer, however/ the
potential for contamination from the Standard Auto site to impact
the surface water in the Red Road canal by means of an overland or
surface water route is remote.
The canal system was started in the early 1900's as a way to drain
lands for farming along the south rim of Lake Okeechobee. Later,
as a result of roads that were built across the area, water became
diked and impounded and subsequent canals were built for flood
control to intercept overland flow of water and divert some of the
water to the southeastern coast of Florida. Because of this direct
connection to the ocean, sea water intrusion became a problem.
Dam-like structures or water control stations with gates to hold
back or release water in the canals were built as a way to guard
against flooding and sea water intrusion. During wet times of the
year, the gates are opened allowing water to flow in the canals
thus lowing ground water levels and preventing flooding. At the
end of the rainy season and during the dry months/ the gates are
closed, allowing water levels to be maintained high enough in the
canals to protect against sea water intrusion.
The hydraulic connection between the Biscayne Aquifer and the canal
system is evident from the variation in canal elevations depending
on precipitation levels. Most of the canal water level elevations
are higher in the area of the site than the surrounding ground
water level elevations when there is less than normal precipitation
and the canal gates at water control stations are closed to prevent
the movement of seawater up the canals. The reverse of this
situation (i.e. canal gates open to release storm water runoff)
results in lower canal water level elevations relative to the
surrounding ground water level elevations.
5.2 Geology
In south Florida, the upper 3,00.0 feet of rocks are composed
chiefly of limestone, dolomite, sand, clay, marl, and shells.
Geologically, the Biscayne Aquifer is composed of soils of Holocene
age and rock ranging in age from Pleistocene through Pliocene. The
1987 ESI at the Standard Auto site documented mostly unconsolidated
surficial deposits consisting of calcareous sands and gravels to a
depth of approximately 28 feet below land surface and quartz sands
to a depth of approximately 48 feet. A harder, consolidated
bedrock unit was reportedly encountered below the surficial
deposits and was described as cavity-riddled, fossiliferous, marine
limestone. At the site, the Biscayne Aquifer extends to a depth of
approximately 110 feet below sea level.
Solution cavities occupy a significant volume of the limestone in
the Biscayne Aquifer, causing it to have high horizontal and
vertical permeabilities. The lower part of the oolitic limestone
is also cavity riddled and is identified by the presence of
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bryozoans. A hard cavernous limestone underlies the bryozoan
layer. Because of the extremely high permeability of this
limestone, all large capacity wells are completed in this part of
the aquifer, generally 40 to 100 feet below the land surface.
5.3
The uppermost hydrogeological water bearing unit in the study area
is the Biscayne Aquifer. The Biscayne Aquifer is the major source
of all the municipal water for the residents of the southeast coast
of Florida from Boca Raton southward and is composed of limestone,
sandstone, and sand.
The major aquifers in south Florida are composed primarily of
limestone and supply varying yields of potable and non-potable
brackish water for municipal and irrigation water use in southern
Florida. The aquifers, ranging from highest to lowest yield, are:
the Biscayne Aquifer of southeast Florida, the Shallow Aquifer of
South West Florida, and the Coastal Aquifer of Palm Beach and
Martin Counties (Figure 4). Underlying these aquifers is a thick
confining layer composed of relatively impermeable beds of clay and
marl which overlie the Floridan aquifer.
The Floridan Aquifer in southern Florida is composed of permeable
limestone and contains non-potable brackish water. The impermeable
beds separating the shallow aquifers and the deeper Floridan
aquifer shield against the upward intrusion of brackish water.
However, there is no shield against the lateral encroachment of
seawater .
Recharge to the Biscayne Aquifer is primarily by local rainfall.
Infiltration is rapid in the areas covered by sand, or where soil
is absent. In the site vicinity, the soil type consists of fine
quartz sand. Discharge is by evapotranspiration, canal drainage,
coastal seepage, and pumping.
Transmissivity (T) of the Biscayne Aquifer ranges from 5.4 X 10*
ftVday (581 cmvsec) where the aquifer is mostly sand to greater
than 1.6 X 106 ftVday (17,200 cmVsec) in the limestone-rich areas.
During the ESI conducted in 1987, site specific values of hydraulic
conductivity (K) were determined to range between 42.8 ft/day
(0.0151 cm/sec) to 102 ft/day (0.036 cm/sec) or an average of 62.6
ft/day (0.0221 cm/sec). Using the relationship T=Kb, a site
specific value for the transmissivity of the unconsolidated
calcareous sands and gravels and quartz sand zone can be estimated:
T = 62.6 ft/day X 48 ft = 3000 ftVday (32.3 cmVsec). This site
specific value for the transmissivity of the unconsolidated zone is
an order of magnitude lower than the published value for the sandy
portion of the Biscayne Aquifer.
Regional flow of ground water in the Biscayne Aquifer of southeast
Florida is seaward. Locally, however, the direction and rate of
10
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LEGEND
r BISCATW AQUIfW. M1O1
SHALLOW AQUIFER OF SOUTH WEST FLORIDA.
MODERATE TO HIGH YIELD
COASTAL AOUIFTR or PALM BEACH AMD
MARTIN COUNTIES. MODERATE YIELD
- LOCAL. DISCONTINUOUS. WATERBEARING
MATERIAL, LOW YIELD
—«—- LINE OF EQUAL DEPTH OF BASE OF AQUIFER.
FEET BELOW SEA LEVEL (NCVC29)
(EOUIOISTANCC - 20 FEET - 6.1 METRES)
FIGURE 4
SHALLOW AQUIFERS
IN
SOUTHERN FLORIDA
&EPA
STANDARD AUTO BUMPER
HIALEAH, FLORIDA
APPROXIMATE SCALE
23 0 U.I 25
(IN MILES)
1 In. • 25 mil«s
(Uo«*M
Ktoto «n« otn
tea_ «»•* 3)
>«. 1*73. ix>s»
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flow may be significantly influenced by the direct surface water
connection of the canal system and/or by pumping from well fields.
Variations in the direction and rate of flow of groundwater was
documented during the ESI and RI. During the ESI in 1987, site
specific groundwater elevations indicated shallow groundwater flow
towards the west. Groundwater elevations during the preliminary RI
in April 199 I/ also indicated a westward trend in groundwater flow
for shallow groundwater monitoring wells. The rate of groundwater
movement at this time was an estimated 88 feet per year.
The rate of groundwater movement differed greatly in 199 1, compared
to previous observations. During the Phase 1 RI in
January/February 1991, groundwater flow in the shallow aquifer was
southeasterly and the rate of flow was approximately 1.7 feet per
day. During the Phase 2 RI in May 1992, two trends were observed
in the aquifer. Close to the site, shallow groundwater movement
was towards the site, while farther from the site, groundwater
movement was to the southwest.
5.4 SnhgiiT-fa.ee
In the northwest corner of the site there is an unused underground
storage tank. Standard Auto Bumper had plans to remove the tank,
however, no action has been taken to date. A gas line extends from
the east side to the west of the site on the north edge of the
property. No other underground structures are known to exist at
the site.
The scope of the RI at the Standard Auto Bumper site included field
studies on the soils and the groundwater. Additionally, the
sediment and the surface water from Red Road Canal were
investigated. Soils were analyzed for the full Target Analyte List
(TAL). The investigation focused on inorganic contaminants for the
following reasons. The primary reason for the reduced sample and
analysis plan to include only inorganic chemicals was based on the
extensive sampling efforts of the ESI. During the ESI, a variety
of organic and inorganic contaminants were found in the former
disposal areas and other areas of interest. Among these organic
compounds were some polynuclear aromatic hydrocarbons (PAHs) and
pesticides. PAHs are associated with creosote products that can be
found in railroad ties and asphalt paving. Pesticides are not
related to the electroplating process and are difficult to
attribute to the Standard Auto site.
Another reason for the reduced analysis is that organic compounds
were not detected in any groundwater samples from monitoring wells
at levels above Federal or State drinking water standards during
the ESI or the RI. However, trichloroethene slightly exceeded the
Maximum Contaminant Level in samples from an onsite industrial
12
-------
well. Full TAL/TCL analyses will be conducted at the completion of
cleanup to demonstrate that the site is clean.
Three areas were identified in the Remedial Investigation as having
the highest concentrations of metals in soils relative to the other
areas. These areas correspond to the former drainfield area north
of the facility building, the loading and unloading area at the
southeastern portion of the site and near the southwest corner of
the site. Concentrations of chromium and nickel in these areas
were one to two orders of magnitude higher than the concentrations
found at most of the other soil sample locations.
5.5.1 Surface Soil
Nineteen metals and cyanide were detected in the surface soil
samples. Aluminum, barium, calcium, chromium, copper, iron, lead,
magnesium, manganese, mercury, nickel, strontium, titanium, and
zinc were detected in nearly every surface soil sample. Surface
soils were collected from the surface to a depth of .8 inches at 17
locations throughout the site.
The chromium concentrations ranged between 2300 mg/kg and 9.4
mg/kg. Table 1 presents information on the ranges of concentration
of target contaminants. Concentrations of chromium in the surface
soil samples were highest near the former drainfield area north of
the facility building, near the southwest corner of the site
property and near the loading and unloading areas at the
southeastern portion of the site (Figure 5).
The three highest concentrations of nickel (4200 mg/kg, 3800 mg/kg,
and 1900 mg/kg) were identified in areas corresponding to the
former drainfield area north of the facility building, the loading
and unloading area at the southeastern portion of the site, and
near the southwest corner of the site property, respectively. The
nickel concentrations ranged from 4200 mg/kg to 8.9 mg/kg.
Copper was detected at concentrations ranging from 16 mg/kg to 600
mg/kg. The highest copper detections were at the same locations as
the highest chromium and nickel concentrations.
Detectable lead concentrations ranged from 7.9 mg/kg to 160 mg/kg.
5.5.2 Subsurface Soil
Nineteen metals and cyanide were detected in the subsurface soil
samples from depths ranging from the 11 to 18 inch interval to the
38 to 43 inch interval. Most of the subsurface samples were
obtained from 2.5 to 3 feet below the surface. The nineteen metals
are: aluminum, antimony, arsenic, barium, calcium, chromium,
copper, iron, lead, magnesium, manganese, mercury, nickel, silver,
strontium, tin, titanium, vanadium, and zinc. A summary of
13
-------
««•"*•
FIGURE y
CONCENTRATIONS OF SELECTED
INORGANIC ANAIYIES OEHCTIO
INSIJWACE SOU DURING THt
PHASf t «l OV91 V92)
SfANUAUl) AUIO HUMPIK
HIAII AM. MOKIDA
B*^ ""' »*«u us IP*, ini.
MMM MlOII) IJ/VU/M ANII
HH»ruM^ inono miAiM in
-------
subsurface soil data for the Standard Auto Bumper site is presented
in Table 1. Figure 6 presents the concentrations of selected
metals for each subsurface soil sample location.
The maximum concentrations of thirteen of the nineteen detected
metals were found in one subsurface soil sample obtained from an
area offsite, near the northwest property corner. Of both surface
and subsurface soil samples, the maximum concentrations for eleven
metal analytes were detected in this subsurface soil sample.
Chromium was found detected in concentrations as high as 9100
mg/kg, 1600 mg/kg, 690 mg/kg, 360 mg/kg, and 200 mg/kg. These
areas correspond to the southwest corner of the site property and
near the former drainfield area north of the facility building.
Relatively high concentrations (340 mg/kgf 170 mg/kg, and 140
mg/kg) of copper were identified in subsurface soil samples which
are located near the southwest corner of the site property and near
the loading and unloading area at the southeastern portion of the
site. Elevated concentrations of nickel, 2300 mg/kg and 970 mg/kg,
are found near the southwest corner of the site property. Slightly
elevated nickel concentrations were found near the loading and
unloading area at the southeastern portion of the site.
Aside from the maximum lead concentration found in one sample of
520 mg/kg, the lead concentration ranged from 99 mg/kg to 2.9
mg/kg.
As part of the RI/FS, the Toxicity Characteristic Leaching
Procedure (TCLP) test was performed on the soil from the site.
Three soil samples were collected from three locations, two surface
samples and one subsurface sample. These locations were in areas
containing the highest concentrations of the contaminants.
The soil did not exceed TCLP regulatory levels as shown in Table 2,
indicating there are no RCRA hazardous wastes at the site. However,
the TCLP results do indicate contaminants can leach, thus
contributing to groundwater contamination.
5.5.3 Groundwater
Preliminary RI. During the preliminary RI in April 1991,
groundwater samples were collected from seven existing monitoring
wells and the industrial well. All samples were analyzed for the
complete TAL and Target Compound List (TCL). A summary of
significant levels of selected inorganic chemicals detected in the
groundwater during this sampling event is presented in Figure 7.
The groundwater samples contained a variety of metals and some
organic compounds. The most pervasive groundwater contamination
was detected in the shallow groundwater monitoring well samples,
particularly from the location directly downgradient from the site.
15
-------
TABLE 1
STANDARD AUTO BUMPER SOIL SAMPLING DATA SUMMARY
(mg/kg)
SUBSURFACE
Contaminant
Concentration Number
Range Detected
Concentrat ion
Average
Total
Number of Background
Samples Concentration
Chromium
Copper
Lead
Nickel
2.7
4.0U -
l.OU -
2.0U -
9100
4700
520
9700
15
13
16
15
STANDARD AUTO BUMPER
719.2
327.95
55.73
948.41
17
17
17
17
2.7
l.OU
l.OU
2.0U
SOIL SAMPLING SUMMARY
(mg/kg)
SURFACE
Contaminant
Chromium
Copper
Nickel
Lead
Cyanide
Zinc
Concent rat ion
Range
9.4
10U
8.9
7.9
0.21U -
10U
2300
600
4200
160
12
400
Number
Detected
14
14
15
17
4
16
Concent rat ion
Average
290.28
118.08
879.22
74.49
1.37
131.11
Total
Number of
Samples
17
17
17
17
17
17
4
Background
Concentration
10U
10U
20U
7.9
0.23U
10U
U - Material was analyzed for but not detected.
The number is the minimum quantification limit.
Source: Remedial Investigation Report for the Standard Auto Bumper Site,
EPA, 1992
16
-------
CHROMIUM
COPPCR
!IAO
MCKCl
CYAMOC
CHROMIUM
COPPER
If AD
MCKa
CYAWDC
CHROMIUM
COPPER
UAD
MCKCl
CYAMOC
CHROMIUM
COPPER
11*0
MCKCl
CYAMOC
RAM AS BROTHERS
AUIO REPAIR
CHROMIUM
COP«H
LEAD
mom.
CYAMOC
CHROMIUM
COPPER
UAO
CHROMIUM
COPPCR
HAD
MCHCI.
CYANUC
CHROMIUM
COPPER 31
UAD 47
MCKCL 310
CYAMDC
SIANOAKD
AUIO
BUWt R
CHROMMM 20
COPPER 37
UAD ••
MCKa 100
CYAMOC 0.97
A - SOII SAMI'll IUCAIIUN
CHROMIUM
COPPCR
UAO 4.9
MCKfl 70
CYANXJC
CHROMUM l»
COPPCR 7S
UAO n
NICKCl 32O
CYANOC
AU CONL1NINAIIONS IN KG/KG
CHROMUM 690
COPPER 340
UAD SO
MCKEL 230C
CYAMOC M
GRAPHIC SCALt
0 M)
riRNANOE/
a NAN SPORT
WPORAIKM
( m fin )
i K;UKI
CHROMUM 160
COPPCR 170
UAD «4
MCKa 970
CYANIOC 3.S
OK SHfClfl)
INO«CANIC ANAIYITii
IN SUBSIIWACI SOII UUHING
PHASt I
SIANDAKI) AUIO UUMI'I H
IIIAII All. II OKIDA
AINIM PIIUIII 11/111/09 AMU
Alii) kll A
IIM'AINM!, ll» AHI) kll All* III
UUiMiAHl MOV* » m/m/»l
-------
TABLE 2
TOXICITY CHARACTERISTIC LEACHING PROCEDURE RESULTS
(M6/L)
SAMPLE
1
2
3
Average
Regulatory
Levels
COPPER CHROMIUM
1.73
1.55
1.85
1.71
—
no regulatory level
0.022
0.015
0.021
0.019
5.0
has been
NICKEL
9.76
9.61
9.33
9.57
—
established
LEAD
0.058
0.038
0.031
0.042
5.0
18
-------
ZCCC3IAT
LLONQ
- tXISUNC MONUORINC Wl.ll
- INDUSIRIAI Will
All CONCINIKAIIONS IN
100
riouRt 7
CONCINIRAIIONS OK SFLECTFI)
INORGANIC ANAI Yll S Of TICII I)
IN CROUNDWAHR. Mil). APRII KI'JI
SIANOARO AUIO HUMI'I R
IIIAI I All. I I OKU)A
&EPA
HAM UAf> S4KJNIJ US IP*. I h'
AJHlAi Illllllt II///U/A9 AMI)
III ft*, MM AI1O Nil AHA III
-------
MCLs (Maximum Contaminant Levels) were exceeded for arsenic,
chromium, iron, lead and manganese in most of the samples.
Trichloroethene, with a MCL of 5 ug/1, was detected at an estimated
concentration of 7 ug/1 in the industrial well onsite. This
chemical will be sampled further during OU #2 for groundwater.
Phase One. During phase one of the RI in December 1991 and January
to February 1992 temporary wells were installed. Existing and
newly installed shallow permanent monitoring wells were sampled and
analyzed for the complete TAL. One sample was analyzed for
purgeable organic compounds in addition to the TAL.
Groundwater concentrations for chromium and nickel were highest in
temporary monitoring wells near the southern site property
boundary. The most pervasive groundwater contamination was
detected in the shallow permanent monitoring well located west and
directly adjacent and downgradient from the former drainfield area
north of the facility building (groundwater sampling data from
temporary and permanent monitoring wells is depicted in Figures 8
and 9, respectively). The sample collected from this area
contained the highest concentrations of chromium, copper, nickel,
and zinc.
The samples collected from the deeper monitoring wells (Figure 9)
and the onsite industrial well did not contain any detectable
chromium, nickel, or copper. Overall the deeper monitoring wells
and the onsite industrial well yielded samples which had low
concentrations of the metals compared to the shallow monitoring
wells.
The ground water samples from six shallow monitoring wells were
analyzed for hexavalent chromium. Hexavalent chromium is a more
toxic form of the metal than trivalent chromium. No hexavalent
chromium was detected in any of the samples.
Phase one of the RI detected groundwater samples with inorganic
concentrations which exceed drinking water standards.
Phase Two. Phase 2 RI field activities were conducted in May,
1992. The purpose of this groundwater sampling event was to
confirm the Phase 1 results and/or identify the necessity for any
additional groundwater sampling. Two deep monitoring wells were
installed and sampled for the complete TAL. The 13 existing wells
were also sampled and analyzed for the same parameters. The
concentrations of selected inorganic analytes identified in the
groundwater samples are presented in Figure 10.
Chromium, copper, lead and zinc were not detected in any
groundwater samples from the shallow monitoring wells. Nickel
exceeded the MCL in only one well.
The results from the newly installed monitoring wells did not
20
-------
5(
CHROMMM II
COPPER
UAO S.3
MCKEl 37
CTAMOC
13061
TIO
T12
CHROMIUM 32
COPPER 22
UAO 130
MCKCL 30
CYAMOC
OlOA
- BAKERY-
r«aunr
CHROMIUM
COHPER
UAO
MKKEl
CVAMOC
75
48
1W
CHROMIUM
COPPER
UAO
MCKU
CYAMDE
410
27
200
100
CHROMMM M
COPPER 27
UAO
MCKEL 48
CVAMOE
-*l 1
114 Al
CH
CO
IE,
I— Ml
NACHON
LUMBER
•ORID
MdALS
QUAiinr
HANUf ACIURING
PRQPUCIS
CHROMIUM
COPPER
IfAO
NICKIl 21
CYAMOE
J05J
1ZL_£J
RIU'S
CONCNt II
Q.LJL......
U
INI-MUM
UASS
UASS I
RAM AS BHOIKHS
AUIO KIPAM
MEIA
,
M
'
1
r
SIANOARO
Bl
MHO
JMPTR
CHROMUM It
CUPPIR It
UAO
MCKll
CYANOE
HROMH
OPPER
EAO'
•CKfl
YAMOE
• •
M sao
ISO -
•3
IBOC -
310
13
V
ft
117
•L
RNAMnFY
•
1
\
N
r^j^TX -\ i[ 1
YAIU 1 1 1 1
CHROMIUM
comR
UAO
NICKli
CYANIOf
. • '_s?r-
( Y/^
( ic
\ *.9~\.
\_-'"
r »• t
CHROMMM 320
CUPPER 110
UAO 110
MCKEL 8/0
CYAMOC
^INANSPORT
^ CORPORAIKM
"X»
__1 .11 J
-/>%^.
^Tvw w"*v^ /v""'r^"'^X)
"v" * "V ^
1
LLONQ
• • IIMHUNAKY M.U.
All CUNCINIKAIIONS IN ^g/l
GRAI^IIIC SCALE
100 0 50 UK)
( IN fin )
MCURL A
CONCCNIRAHONS Of SHECHO
INORGANIC ANAIYKS DlUCirD IN CM(IUNI)
WAI1H fHOM ITMPOHARY MONIJOMINC
WlllS DURING nil PMASl 1 Rl ((>'/»•')
SIANDAKD AUIO FJUM»'H<
IIIAII AH. IIOKIDA
^ B^V^A B><* MM* MJU*LI: ui ""*• ""
'9?/B— ••^•H H»»IKKS m:>ni> mi»n«i to
Ll^^^l VVUniMIAM* SUNM r 1X/0//KJ
-------
CHROMIUM
COPPER
LEAD
WCKll
CYAN**
mi-yoN
CLASS
CNRCMWM
COPHM
UAO
MCKCI
CYAMOC
LLULNQ
• - [XIMINC MONIKJHINC NEIL
• - INDUS 1HIAI Mil
ALL CONCCNIKAFIONS IN
GRAPHIC SCALE
( IN HII )
MCUHl 4
CONCTNIRAIIONS Of
INORGANIC ANAlYfTS 01 FTCflO
IN UKOONOWArtH. ISO PHASt I Rl
SFANDAHO AUIO HUMPIK
IIIAIt AM. II OKIDA
xEPA
us ICA. int.
. .
MHIM I11IIIU I1/IU/S» AMU
IdOIOIS 10 AltO
RIIAII«I IU
(X/01/»
-------
ZCSC3IAT
CHROMIUM --
CUWW
LEAD
MCKll 95
CYAMOC
CHHOUnM
CUHWR
UAO
NOdl
CYANIOC
-4({/
CHROMIUM --
COPPtR
HAD
MCKtl 67
CYAMOC
rtNNAMKI
RANSPORI
CORPORA DON
BIOS
CONCHCTC
0 LJL
M— * -—•—-- • -
CHROMIUM 62
COPPER
UAO M
MCKCl
CYAMOC
LLULNL!
• - tXISIING MUNIIONINC WEIL
« - INDUS INIAL Mil
ALL CONCENIRAIIONS IN jjg/l
GRAPHIC SCALE
0 SO 100
( IN fill )
riCUHL 10
CONCCNIHAIIONS Of SlUCrtO
INOHCANIC ANAIYIfS OttlCnD
N CROUNOWAIIR. tMJ. PHASI. 2 Hi (OS/9^
SIANOAKO All 1C IIHMI'f k
HIAII AH. II IlKlDA
AIKI/U I'Miiiii i//A>/g« AMI
lilt AlMKi I IN Alllt bl| AIIVI Ml
-------
appear to coincide with previous sampling results or with the
current groundwater data. Chromium, lead, and nickel were detected
only in the two new deep monitoring wells and> not in any of the
other deep wells. The concentration of these three metals were at
low concentrations slightly above their detection limits. The
chromium concentration was slightly above the State drinking water
standard. The concentration of aluminum found in these two samples
was two orders of magnitude higher than was found in any other
sample. Based on these results, and the sample clarity with
respect to that obtained in all other samples it appears that the
samples may have been collected prior to complete development.
Another sampling event will determine more representative
groundwater conditions.
The results from the third round of sampling since April 1991
indicate significantly lower concentrations for most of the
inorganics detected when compared to the results from the second
round of sampling. The analytical results of the second and third
round of groundwater sampling have indicated lower concentrations
of inorganic contamination than the first round of groundwater
sampling. The RI Report concluded that the particles responsible
for elevated levels of metals such as chromium and nickel, found in
early sampling events, had been removed as a result of additional
well development conducted during the RI. The report also
determined that the last sampling results are the most
representative of groundwater quality and that nickel may be the
only contaminant of concern at the Standard Auto Bumper site.
Additional field work will be performed to confirm the condition of
the groundwater during operable unit #2.
5.5.4 Surface Water and Sediment
Three sediment samples and surface water samples were collected in
Red Road Canal and analyzed for TCL/TAL and TAL, respectively. The
sediment samples contained metals which did not appear to be
related to the site, with the exception of lead at a maximum
concentration of 120 mg/kg. The surface water samples from the
same location contained no detectable chromium, copper, cadmium,
nickel, lead, arsenic, or cyanide.
The RI concluded that surface water data could not be correlated
with the soil and groundwater data for the site. Also the
upgradient surface water concentrations were nearly identical to
the downgradient concentrations.
6.0 SUMMARY OF SITE RISKS
As part of the RI/FS, EPA prepared a Baseline Risk Assessment for
the Standard Auto Bumper site in July 1992. This risk assessment
was carried out to characterize, in the absence of remedial action
(i.e., the "no-action" alternative), the current and potential
threats to human health and the environment that may be posed by
24
-------
exposure to contaminants migrating from the soil. Results are
contained in the Final Baseline Risk Assessment, dated July 21,
1992. The assessment considers environmental media and exposure
pathways that could result in unacceptable levels of exposure now
or in the foreseeable future. Data collected and analyzed during
the RI provided the basis for the risk evaluation. The risk
assessment process can be divided into four components:
contaminant identification, exposure assessment, toxicity
assessment, and risk characterization.
6.1 Ch**m'*cal8 of Concern
The risk assessment began by evaluating the soils data in the RI to
identify the chemicals most likely to contribute a majority of the
risk. Five contaminants in the surface soils were selected to
represent the major potential health risks at the site based on
concentrations at the site, toxicity, and physical/chemical
properties that affect transport and movement. Chemical data from
the 16 surface soil samples (the control or background sample was
not included) used to identify potential contaminants of concern
(COCs) is shown on Table 3. The Baseline Risk Assessment Report
determined that chromium, copper, lead, nickel and zinc were COCs
at this site.
Soil contaminant migration by way of surface water runoff is not
likely at this site. The railroad spur directly west and adjacent
to the site is significantly higher in elevation than the site.
Infiltration through the sandy soil would be expected to be
relatively rapid. Surface floods have not been observed at this
site during the RI. The removal action and this remedial action
reduces the likelihood of this pathway occurring.
The depth to groundwater at the Standard Auto Bumper site is
typically four to six feet below ground surface. Mobile soil
contaminants above the water table posed the principal threat as
they can migrate to the groundwater and thus pose a risk to the
Biscayne Aquifer, which is the sole source of municipal drinking
water for southeast Florida.
Exposure pathways consist of four elements: 1) a source and
mechanism of chemical release to the environment, 2) a retention or
transport mechanism for the released chemical, 3) a point of
potential human contact with the contaminated medium, and 4) a
human uptake route (intake of contaminated media) at the point of
exposure.
Currently, the site and the surrounding area is an industrial
setting made up of numerous small businesses. The closest
residents to the site are 350 feet to the west beyond the Red Road
Canal. Therefore, exposure pathways could involve onsite workers
25
-------
TABLE 3
CONTAMINANT DATA FOR THE STANDARD AUTO BUMPER SITE
SURFACE SOILS
CONTAMINANT
Aluminum
Antimony
Barium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Strontium
Tin
Titanium
Vanadium
Zinc
Cyanide
FREQUENCY
OF
DETECTION
16/16
1/16
14/16
2/16
16/16
15/16
1/5
15/16
16/16
16/16
16/16
16/16
13/16
16/16
16/16
3/16
16/16
5/16
16/16
4/16
CONCENTRATION
RANGE
(mg/kg)
710
<6
31,000
<15
<2
890
8.4
320
9.7
<.05
8.9
98
<5
13
<2
26
<0.21
7,400
17
43
10
260,000
2,300
3.2
600
17,000
160
19,000
85
0.35
4200
820
54
420
29
400
12
AVERAGE
CONCENTRATION
{mg/kg)
5,930
10.1
18.0
2.0
118,750
308
1.7
126
4,431
79.2
2,130
43.9
0.13
934
407
13.8
53.1
5.9
139
1.5
BACKGROUND
CONCENTRATION
(mg/kg)
960
<30
<5
180,000
820
7.9
1,700
23
<0.05
<20
400
<25
29
<0.23
Frequency of detection is reported as the number of .samples the
chemical was detected above detection limits out of the total number
of samples in which the chemical was analyzed.
Material was analyzed for but was not detected. The number is the
minimum quantitative limit, which varies due to the presence of
other compounds in the sample.
26
-------
for current use and residents for potential future use. Based upon
the four elements above, the exposure analysis identified the
following exposure pathways:
• inhalation of fugitive dust from the surface
soils by onsite workers, site visitors, or
hypothetical future residents
• incidental ingestion of surface soils by
onsite workers, site visitors, or hypothetical
future residents
• dermal contact with surface soils by onsite
workers, site visitors, or hypothetical future
residents
The hypothetical future resident scenario was applied to an adult
resident and a child resident. Reasonable maximum exposure point
concentrations of chemicals of concern in air, surface soils, and
subsurface soils were estimated to quantify intakes of chemicals
for each exposure pathway. General assumptions for the calculation
of the intake factor regardless of pathway and specific assumptions
for each exposure scenario are used to estimate intakes. These
assumptions are contained in Appendix B. The Appendix also
contains the exposure parameters for each receptor.
Reasonable maximum exposure point concentrations of COCs are
estimated on the basis of transport and dispersion modeling and/or
field measurement. These concentrations are used to estimate
intakes of chemicals for each exposure pathway. For the onsite
worker, the intake factor for inhalation of fugitive dust is 1.9E-1
mVkg-day for nonearcinogens and 6.9E-2 mVkg-day for carcinogens;
for incidental ingestion of soils is 4.9E-7 mg/kg-day for
none arc inogens and 1.7E-7 mg/kg-day for carcinogens; and for dermal
contact with soils is 2.0E-8 mg/kg-day for none arc inogens and 7.0E-
9 mg/kg-day for carcinogens. Intake factors for all exposure
pathway scenarios are provided in Table 4.
The site is likely to continue to be used for business or industry
in the future; however, the potential for future land use to be
residential does exist given the proximity of the residents.
6.3 Toxicity Assessment
To assess the possible toxicological effects from exposure, health
effects criteria are derived from a review of health and
environmental standards and published toxicological studies.
For risk assessment purposes, individual pollutants are separated
into two categories of chemical toxic ity, depending on whether they
exhibit carcinogenic or nonearcinogenic effects.
27
-------
TABLE 4
INTAKE FACTORS
PATHWAY-SPECIFIC
EXPOSURE
ONSITE-WORKER SITE VISITOR
FUTURE ADULT
RESIDENT
FUTURE CHILD
RESIDENT
Inhalation of
Fugitive Dust
noncarcinogenic
(mVkg-day)
carcinogenic
(mVkg-day)
Incidental Ingestion
of Soils
noncarcinogenic
(mg/kg-day)
carcinogenic
(mg/kg-day)
Dermal Contact with
Soils
noncarcinogenic
(mg/kg-day)
carcinogenic
(mg/kg-day)
1.9E-1
6.9E-2
4.9E-7
1.7E-7
2.0E-8
7.0E-9
4.2E-2
6.0E-3
2.1E-7
3.0E-8
1.1E-8
1.6E-9
2.7E-1
1.1E-1
1.3E-6
5.9E-7
7.3E-8
3.1E-8
1.27
4.8E-11*
1.2E-5
NC
3.2E-7
NC
* - Memorandum from Solomon Pollard, Jr., Regional Toxicologist, to Barbara Dick,
Remedial Project Manager, September 4, 1992
NC - Not calculated since there are no oral slope factors
Source: Final Baseline Risk Assessment for the Standard Auto Bumper Site
28
-------
Carcinogens. Slope factors (SFs) have been developed by EPA's
Carcinogenic Assessment Group for estimating excess lifetime cancer
risks associated with exposure to potentially carcinogenic COCs.
SFs, which are expressed in units of (mg/kg-day)'1, are multiplied
by the estimated intake of a potential carcinogen, in mg/kg-day, to
provide an upper-bound estimate of the excess lifetime cancer risks
associated with exposure at that intake level. The term "upper
bound" reflects the conservative estimate of the risks calculated
from the SF. Use of this approach makes underestimation of the
actual cancer risk highly unlikely. Slope factors are derived from
the results of human epidemiological studies or chronic animal
bioassays to which animal-to-human extrapolation and uncertainty
factors have been applied (e.g., to account for the use of animal
data to predict effects on humans). Slope factors for the
identified COCs are presented in Table 5.
Nonearcinoaens. Reference doses (RfDs) have been developed by EPA
for indicating the potential for adverse health effects from
exposure to COCs 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
and are listed for site COCs in Table 6. Estimated intakes of COCs
from environmental media (e.g., the amount of a COC 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).
6.4 Characterization of Risk
Potential noncarcinogenic and carcinogenic risks posed by the
chemicals of concern in the various exposure pathways were
evaluated. Nonearcinogenic effects are characterized by comparing
estimated chemical intakes with chemical-specific RfDs and are
expressed as the hazard quotient. Individual hazard quotients are
summed for all chemicals in an exposure pathway to provide the
Hazard Index (HI). HI values for the site are shown in Table 7.
The values exceeding unity indicate potential unacceptable
nonearcinogenic risk. All chemicals of concern posed cumulative
hazard indices below one for each exposure pathway, with the
exception of the future child resident scenario. The HI for
ingestion of surface soils for this child receptor is 8.5, due to
the chromium and nickel in the soil.
Potential risks from lead exposure were calculated for children
using the Uptake Biokinetic Model, since children are very
sensitive to lead exposure. The assessment determined that the
level of contamination would result in a blood-lead level below 10
ug/dL, the level of concern, if a family with a child established
a residence at this site in the future.
29
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TABLE 5
CARCINOGENIC TOX1CITY VALUES FOR
CONTAMINANTS OF CONCERN
IN SURFACE SOILS
INGESTION
SLOPE FACTOR
INHALATION
SLOPE FACTOR
DERMAL
SLOPE FACTOR
CONTAMINANT
(mg/kg-day)'1
(mg/kg-day)'1 (mg/kg-day)
-i
Chromium
Copper
Lead
Nickel
Zinc
NA
NA
NA
NA
NA
4.2E+1
NA
NA
8.4*
NA
2 . OE+2
NA
NA
NA
NA
* Integrated Risk Information System or Health Affects
Assessment Summary Tables (HEAST), 1991.
Adjusted from an SF to an absorbed dose SF.
NA - Not Available
Source: Final Baseline Risk Assessment for the Standard Auto
Bumper Siter"
30
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TABLE 6
NONCARCINOGENIC TOXICITY VALUES FOR
CONTAMINANTS OF CONCERN
IN SURFACE SOILS
INHALATION
RfD
INGESTION
RfD
ADJUSTED
DERMAL RfD
CONTAMINANT
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
Chromium
Copper
Lead
Nickel
Zinc
5
.7.1E-71
NA
NA
NA
NA
5.0E-31
3.7E-21
NA
2.0E-21
2.0E-11
2.5E-22
0.1852
NA
O.I2
I2
Integrated Risk Information System or Health Affects
Assessment Summary Tables (HEAST), 1991.
Adjusted from an oral dose to an absorbed dose RFD.
1.
2.
NA - Not Available
Source: Final Baseline Risk Assessment for the Standard Auto
Bumper Site
31
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TABLE 7
HAZARD INDICES
FOR NONCARCINOGENS FOUND IN SURFACE SOIL
Fugitive Dust
Inhalation
Hazard Indices
Cont ***" t nant
Chromium
Copper
Lead
Nickel
Zinc
HAZARD INDEX:
Ingestion of
Contaminant
Chromium
Copper
Lead
Nickel
Zinc
HAZARD INDEX:
Ons ite
Worker
8.5E-5
NA
NA
NA
NA
8.5E-5
Surface Soils
Ons ite
Worker
0.12
0.0038
NA
0.14
0.00045
0.269
Adult
Resident
0.00012
NA
NA
NA
NA
0.00012
Hazard
Adult
Resident
0.4
0.012
NA
0.47
0.0014
0.88
Child
Resident
0.0006
NA
NA
NA
NA
0.0006
Indices
Child
Resident
3.8
0.12
NA
4.6
0.014
8.5
Visitor
1.9E-5
NA
NA
NA
NA
1.9E-5
Visitor
0.064
0.0019
NA
0.075
0.00023
0.14
Dermal Contact
With Surface
Contaminant
Chromium
Copper
Lead
Nickel
Zinc
Soils
Ons ite
Worker
1.2E-3
3.7E-5
NA
1.4E-3
4.4E-6
Hazard
Adult
Resident
0.0044
0.00014
NA
0.0053
1.6E-5
Indices
Child
Resident
0.0019
0.00059
NA
0.023
7.15E-5
Visitor
0.00068
2.0E-5
NA
0.0008
2.4E-6
HAZARD INDEX:
0.0026
HAZARD INDEX
ACROSS ALL PATHWAYS 0.27
0.0026
0.88
0.043
8.5
0.0015
0.14
NA - Not Available
Source: Final Baseline Risk Assessment, July 21, 1992
32
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Carcinogenic risks are estimated as the incremental probability of
a person developing cancer over a lifetime as a result of exposure
to a potential carcinogen. The chemical intake level is multiplied
by the cancer potency factor. An excess lifetime cancer risk of
1E-6 indicates that an individual has a one in one million
additional chance of developing cancer over a 70-year lifetime as
a result of site-related exposure to a carcinogen under the
specific exposure conditions at a site.
The NCP states that sites should be remediated to chemical
concentrations that correspond to an upper-bound lifetime cancer
risk to an individual not exceeding 10~6 to 10'4 excess lifetime
risk. Carcinogenic risk levels that exceed this range indicate the
need for performing remedial action at a site. The carcinogenic
risk levels are shown in Table 8. No carcinogenic risks levels
exceeded 10E-6, except for the child resident scenario. The
carcinogenic risk level from surface soils for the child receptor
is 2.5E-5, due to the risk from chromium and nickel inhalation.
The estimate of carcinogenic risk is conservative and may
overestimate the actual risk due to exposure.
In summary, an unacceptable nonearcinogenic and carcinogenic risk
is present, primarily from chromium and nickel at this site.
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this ROD, may present an imminent and substantial endangerment
to public health, welfare, or the environment.
6.5 Environmental Risks
The ecological effects due to releases from contaminated soils are
not expected to be significant for a variety of reasons. First,
this site does not provide habitat resources for wildlife, due to
the industrial nature of the site. Second, the site and canal data
and the nature of the relationship of the canal to the site do not
indicate there is an offsite environmental risk. The sampling data
for surface water from the nearby Red Road Canal indicates no
relation to site contamination. Also, canal sediments indicate
minor levels of contamination that cannot be linked to the site,
due to the high amount of traffic and industrial activity between
the site and canal. DERM has been made aware of the findings. It
is likely that the lead and zinc could be a result of traffic or
industrial influences and not the site. Contamination via surface
water discharge is not likely due to the businesses, elevated
railroad, and four-lane road located between the site and the
canal.
7.0 REMEDIATION GOALS
Risk Assessment remediation goals were developed for chromium and
nickel based upon the exceedance of acceptable EPA standards (1 for
hazard index and 10'6 for risk level) for the child receptor for the
33
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TABLE 8
CARCINOGENIC RISK LEVELS
FOR SURFACE SOILS
Risk Level
Pathway
Fugitive Dust
Inhalation
Chromium
Nickel
Ingestion of
Surface Soils (Lead)
Onsite Worker
7.6E-10
7.6E-11
NA
Adult
Resident
1.2E-9
1.2E-10
NA
Child
Resident Visitor
2.3E-5
2.3E-6
NA
6.7E-11
6.5E-12
NA
Dermal Contact with
Surface Soils (Lead) NA
TOTAL RISK
FROM SURFACE SOIL: 8.4E-10
NA
1.3E-9
NA
2.5E-5
NA
7.4E-11
NA - Not Available
Source: Baseline Risk Assessment, July 21, 1992
34
-------
COCs. The remediation goal was developed to provide a level that
would result in a risk level of less than 10~* and a hazard index
of .less than 1.0. Under these conditions, the remediation goal of
total chromium is 519 mg/kg, hexavalent chromium is 52 mg/kg, and
nickel is 1600 mg/kg.
The EPA determined that nickel and chromium soil remediation goals
(maximum soil concentrations of nickel and chromium) are necessary
to also protect groundwater. These remediation goals are designed
to insure that leachate from the soil will not cause concentrations
of these metals in groundwater to exceed the MCLs. This is
important because the Biscayne Aquifer is located beneath the site
and is the sole source of municipal drinking water for southeast
Florida.
Three groundwater models were used to determine these soil
remediation goals. The fate and transport model, MULTIMED, was
used to calculate the levels of contribution to groundwater that
would be caused by given soil levels of nickel and chromium. The
geochemical, metals speciation model, MINTEQA2, was used to
determine the relative mobilities of nickel, chromium, and other
possible contaminants at the site. And, finally, the results of
MULTIMED were cross-checked with a leaching-flow continuity model,
the SUMMERS MODEL, to arrive at the final soil cleanup level for
nickel.
Nickel
A soil/water distribution coefficient (Kd) for nickel of 35
milligrams of nickel/kilogram of soil per milligram of nickel/liter
of water (or 35 I/kg) was determined for the site by EPA's
Environmental Research Laboratory. This Kd is fairly low,
indicating that divalent nickel (the common species of nickel in
surface and groundwater) is considerably more soluble and mobile
than many other metals, such as lead or trivalent chromium. Using
this Kd, the soil cleanup level calculated for nickel was 370
mg/kg. This cleanup,-level should insure that nickel leaching from
the soil will not result in a groundwater concentration exceeding
the nickel MCL of 0.100 mg/1 (100 ug/1). This level of 370 mg/kg,
for the protection of groundwater, is considerably more stringent
than the protective level for direct exposure to soil calculated in
the risk assessment (1600 mg/kg).
Chromium
Chromium can exist in one or both of two oxidation states under
normal environmental conditions: trivalent chromium [Cr (III)] and
hexavalent chromium [Cr(VI)]. Chromium can be converted between
the two oxidation states, but typically it does not. For Cr(III)
to be oxidized to Cr(VI), a catalyst and an oxidizing agent (such
as manganese dioxide), must usually be present under very acid
conditions. The mobilities of the two species of chromium are also
35
-------
quite different. Cr(VI) is extremely mobile, even more so than
nickel; but Cr(III) is virtually immobile. Cr(III) is very
insoluble and adsorbs strongly to soil particles.
EPA analysis for Cr(VI) in the groundwater indicated none present,
with a minimum detection level of 10 ug/1. Back-calculating this
level through the MOLTIMED model showed 10 ug/1 in the groundwater
would be equivalent to only 0.05 mg/kg of Cr(VI) in the soil. This
indicates that virtually all chromium present must be Cr(III) and
that particulate transport of Cr(III) on colloidal material is the
most likely mechanism through which Cr is found in the groundwater.
While this mechanism cannot be modeled at present, a reasonable
assumption is that adsorption of these colloidal particles onto the
aquifer matrix would decrease the measurable amount of total Cr in
the groundwater over time.
Because of the uncertainties of modeling the fate and colloidal
transport of Cr(III), a toxicological approach was used. This
approach considers the uncertainty of both the oxidation states of
chromium and toxicological effects of both Cr(VI) and Cr(III).
This approach resulted in a soil cleanup recommendation for total
chromium of 519 mg/kg and hexavalent chromium of 52 mg/kg, based on
an inhalation risk, which will also insure that any leachate from
the site will not cause the State drinking water standard (0.1
mg/1) or MCL (0.1 mg/1) for chromium to be exceeded.
Other Remediation Considerations
High soil concentrations of nickel and chromium are typically found
at the site in areas which also contain the highest concentrations
of other metals, such as copper, lead, and zinc. These metals
would be removed as nickel and chromium is removed, therefore
reducing the overall cumulative risk below protective levels for
both soil and groundwater. In cleaning up soils above the water
table at the site which contain nickel above 370 mg/kg, total
chromium above 519 mg/kg, and hexavalent chromium above 52 mg/kg
these protective levels would be attained.
These soil cleanup goals are expected to insure that drinking water
standards would not be exceeded in the downgradient groundwater.
This expectation, subject to verification by groundwater
monitoring, would minimize the measures necessary for groundwater
remediation which will be addressed in OU #2. These cleanup goals
will also reduce the risks associated with direct health threats to
a child, considering the future child resident scenario, to
protective levels.
Based on analytical data collected during the RI and presented in
the RI Report, a total of 2500 cy of soil are estimated to contain
contaminants above the soil remedial goals of 370 mg/kg nickel, 519
mg/kg total chromium, and 52 mg/kg hexavalent chromium.
36
-------
8.0 DESCRIPTION OF ALTERNATIVES
A feasibility study was conducted to develop and evaluate remedial
alternatives for contaminated soils at the Standard Auto Bumper
site. Remedial alternatives were assembled from applicable
remedial technology process options and were initially evaluated
for effectiveness, implementability, and cost. The alternatives
meeting these criteria were then evaluated and compared to nine
criteria required by the NCP. The NCP also, requires that a no-
action alternative be considered at every site to «erve primarily
as a point of comparison for other alternatives.
8.1 Alternative 1 - Ho Action
Capital Cost: 0
Present Worth (PW) Operation & Maintenance (O&M) Cost: $94,700
Total PW: $94,700
Months to Implement: None v
This alternative does not provide any remedial activities to
address the source of contamination. Contaminants in the soil
would continue to leach into the groundwater. Monitoring for at
least 30 years would be included to evaluate trends in the
contaminants' concentrations in the groundwater due to the
continued migration of contaminants in the soil. Existing
monitoring wells would be used for long-term groundwater
monitoring.
Because this alternative would result in contaminants remaining on-
site, CERCLA requires that the site be reviewed every five years.
If indicated by the review, remedial actions would be implemented
at that time to remove or treat the contaminated soil.
The No Action alternative was considered as a baseline option for
comparison to other remedial action alternatives.
8.2 Alternative 2 - Excavation and Offsite Disposal
Capital Cost: $298,000 Total PW: $338,186
PW O&M: $40,186 Months to Implement: Two
This alternative would consist of excavating the contaminated soil
and loading it onto trucks and hauling it to a Florida Class I
solid waste landfill. After excavation, clean backfill material
would be placed and the area would be regraded.
The landfill requires all soils to be nonhazardous waste as defined
by 40 CFR 261. Because it has been confirmed during the RI/FS that
the soil at the site is neither characteristic or listed hazardous
waste, DERM has approved the disposal of the contaminated soil at
the county or other local landfill. Wastes are considered to be
RCRA characteristic if they exhibit Toxicity Characteristics (TC).
37
-------
The TC rule specifies chemicals which, if present in waste at or
above regulatory levels set in the rule, make the waste a hazardous
waste. The contaminants at Standard Auto Bumper were below the
regulatory levels.
The contaminated soil would be excavated to either the cleanup
level or the point when the water table is encountered. Dewatering
would be very difficult at this site, due to the high
transmissivity of the aquifer. Groundwater is estimated to be at
a depth of 4 to 8 feet. Confirmation samples would then be
collected at the base of any excavation not into the groundwater.
If the results indicated that contaminants are still above cleanup
levels (370 ing/kg nickel, 52 mg/kg hexavalent chromium, and 519
mg/kg total chromium), then additional soil would be removed until
the cleanup level is met or groundwater is reached. If all cleanup
goals were attained the area would be backfilled with.clean soil.
For optimal performance of this remedial action alternative, the
soils would be excavated during dry periods of the year. As
determined in the previous section, the site contains separate
blocks of areas to be excavated. At a minimum, excavation would
occur in the areas indicated on Figure 11. The total volume to be
excavated would be approximately 2500 cubic yards.
The excavated soil would be placed in containers or trucks by
standard dirt-lifting equipment, such as a backhoe, and transported
to the landfill. DERM would be notified that the soil would be
taken to the landfill. Transportation routes to the landfill would
be established for safe transport.
Periodic groundwater monitoring would determine the effectiveness
of the alternative at reducing migration of inorganic compounds to
the groundwater. Existing wells would be sampled periodically for
up to 5 years.
8.3 Alternative 3 - Excavation, Onsite Soil Washing.
and Onsite Replacement
Capital Cost: $878,000 Total PW: $891,650
PW O&M: $13,650 Months to Implement: Seven
Alternative 3 consists of excavating the contaminated soils,
washing the soil with the washwater and/or solvent, placement of
clean soil back into the excavated area, washwater treatment, and
sludge disposal. The replaced soil would be covered with clean
soil and graded. Excavation would follow the procedure outlined in
Alternative 2 above.
As shown in Figure 12, the soil washing process would consist of a
temporary soil mixing/scrubbing unit to uniformly distribute the
solvent washwater in the soil. As the 2500 cy of excavated soil is
placed in the unit in batches, the washwater and solvent is mixed
thoroughly with the contaminated soil. Rinse water is then applied
38
-------
HAMAS 8ROTMCRS
AUIO RtPAM
*
IS
S02
1-6 FT. 0-6 FT
WPIM DtPIM
Sfli i
11
rr :JD
LLGLNC
A - SOM. SAMPIl LOCATION
APPROXIMATE ARfAS WHERE
SOU IS ABOVE CLEANUP COALS
GRAPHIC SCALE
0 50 100
( IN FEET )
FIGURE ||
SOIL ABOVE CLEANUP GOALS
STANDARD AUTO BUMPER
IIIAIFAM. FIOKIOA
"KM
IOCAIHNS IOCAKO MLAnvl ID
-------
Figure 12
SoiV washing system.
Coolnminaled Soil
Feeder
Rough
Screen
Oversize
Nun Soil
Materials
and Debris
Makeup
Water
Scruhlii'd Sell
j
i
Clean Air
Discharge
t
1 Air Cleaner
i
Drum Screen
Water Knife
Soil Scrubber
T 1
Recycled
Stripper Spray
P rT-y
*
Exhaust
from Hood
?mm
^ i
Slurry
Clean
Rinse
rr
rL
Filler
Backwash
Skimmings
to Disposal
Exhaust f
from Hood 1
Counier-Cuiiont
Chemical
Exlractur
i
Clan
1
Washing Fluid Recycle
i
Spent
Washing
Fluids
1,0, | I
Clarified
Washing Tluul •
1 »
_J
-2mm
Scrubbed
Soil
£ Fun
DlS|
Dewatering
Device
•s Id
Spent
Carbon
Source: UFA
-------
to the soil to remove any residuals. Any remaining washing agent
within the soils would be removed with a non-hazardous solvent. The
clean rinsed soil would be sampled to verify all contaminants meet
the cleanup goals. If all cleanup goals are met, the soil would be
replaced on site and the excavation area backfilled and regraded as
needed. If cleanup goals are not met, then the soil would be
washed again.
The collected washwater containing the contaminated soil particles
would undergo dewatering treatment onsite, such as gravity
separation, flocculation, or vacuum filtration. The concentrated
fines from the dewatering are estimated to be 10% of the original
mass of the treated soil. These fines would be treated through
solidification or disposed in a RCRA hazardous waste landfill,
depending on the quantity and concentration of the contaminants.
The fines would be tested prior to offsite disposal. These fines
would probably be characterized as RCRA characteristic wastes for
lead, chromium, cadmium, or arsenic because the contaminants are
concentrated into the smaller volume of soil.
The TCLP would be performed on the concentrated fines from the soil
washing process prior to disposal. If the fines exceed any of the
leachate regulatory levels, the fines would be handled as hazardous
waste. For offsite disposal the fines would be manifested by a
licensed hazardous waste hauler and transported to an approved RCRA
Subtitle C hazardous waste landfill. For onsite disposal, the
fines would be treated to comply with the TCLP regulatory levels.
The rinse water may be treated before it would be recycled to the
soil washing process.
Screening level treatability tests performed during the RI
indicated soil from the site was not amenable to use of
hydrochloric acid as an extracting agent, indicating another
treatability test would be necessary prior to actual application of
this alternative.
8.4 Alternative 4 - Excavation. Stabilization/Solidification
and Onsite Disposal
Capital Cost: $232,000 Total PW: $385,225
PW O&M: $153,225 Months to Implement: Three
This alternative consists of excavating the contaminated soils,
chemical stabilization/solidification of the soils and placement
onsite. A treatment diagram is provided on Figure 13. Excavation
would follow the same procedure as described in the above
alternative. The 2500 cy of excavated soil would then be placed on
a temporary storage pad or directly into the fixation units.
Soil would be processed in the fixation units onsite with one or
41
-------
Stabiliza//on solidification.
Bulk
Liquid
Storage
\/
Bulk
Solids
Storage
v s
^^.
Wasie r
Feed C
\
Pu.-^p
Liquid Chemical
Feed Pump
1
Mixer
— O
To Disposal
3' ' cr Curing
A.-93
Source. EPA
Figure 13
-------
more fixation/solidification agents such as silicate and portland
cement or fly ash to ensure the new material remains non-hazardous,
with respect to the contaminant leachability, and to ensure the
contaminants do not contribute to groundwater degradation. Inside
the process unit as the soil enters the mixer approximately 10%
water is added along with the cement dry agent. The operation is
similar to cement mixing and when the mixture is at a wet concrete-
like consistency, a liquid reagent can be added, which enhances
chemical encapsulation of the metals.
This solidified mass can be transferred from the mixer using a pump
to the desired placement location. The mass would be tested
for compressive strength. Unconfined compressive strength at the
design cure period would be at least 50 psi. Permeability would be
required to be less than 10~5 for land burial. The treated soil
would be replaced in excavation areas and is expected to undergo a
15-25% increase in volume. The specific placement would be
determined and evaluated during the remedial design and would
consider the depth of the water table. The fixation process units
would be set up on site. Samples would be required from the
treated soil to assure compliance with long-term leachability
criteria. The solidified monolith would be covered with soil and
vegetated. Deed restrictions would be implemented to ensure the
integrity of the solidified material.
For placement of treated soil below the surface, long-term O&M
would include monitoring wells surrounding the monolith.
Groundwater monitoring would determine the effectiveness of the
alternative at reducing migration of inorganic compounds to the
groundwater. Existing wells or new wells would be sampled
periodically for a minimum of 30 years after the construction is
completed.
Onsite maintenance would also be required and would include
checking the monolith area for erosion. The screening level
treatability test performed during the RI indicated
stabilization/solidification was effective in reducing TCLP levels
in nickel and copper. Lead was not affected and chromium TCLP
levels increased but were still below TCLP regulatory levels.
Another treatability test would be necessary prior to
implementation of this alternative to determine optimal stabilizing
agents. However, this is a proven treatment for metal-contaminated
wastes.
9.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The remedial alternatives developed in the FS for contaminated soil
were analyzed in detail using nine evaluation criteria. The
resulting strengths and weaknesses of the alternatives were then
weighed to identify the alternative providing the best balance
among the nine criteria. These criteria are 1) overall protection
of human health and the environment; 2) compliance with applicable
43
-------
or relevant and appropriate requirements (ARARs); 3) "reduction of >•
toxicity, mobility, or volume through treatment; ' 4) long-term
effectiveness^ and permanence; " 5) shorty-term effectiveness; tf)
implementability; 7) cost; 8) state acceptance; and 9) community
acceptance*. -.The first two criteria are .essential and must be me\ -
before an-^alternative is considered^ffurther. The next frv«£
criteria are used to further evaluate all options that meet the
first two dg&beria. The final two ciSferia are used to further*
evaluate the'/propos'ed plan after thec^foblic comment period has 6
ended and comments from the community^ and the State have beenr
received. This evaluation of eaoh of tlie alternatives.-against the.*
nine criteria is summarized below.
Overall Protectiveness. All of the alternatives except the no
action alternative are protective of human health and the
environment and comply with the ARARs identified for the site or
obtain an equivalent level of performance. Therefore, Alternative
1, no action, is not acceptable and will not be considered further.
Risk of exposure from further migration of the contaminants through
the soil to the groundwater is reduced in Alternatives 3 and 4 by
treating the contaminated soil to the cleanup levels and in
Alternative 2 by removing the contaminated soil to the cleanup
levels. Alternatives 1, 3f and 4 all provide protection from
contaminant migration from the soil to the groundwater. In
addition, risk associated with the child resident scenario is
minimized by these alternatives.
Compliance with ARARs. All alternatives would comply with the
Federal and State action-specific ARARs. Applicable action-
specific requirements would be the Resource Conservation and
Recovery Act (RCRA) regulations (for hazardous wastes as defined by
40 C.F.R 261). Because there are no RCRA listed or characteristic
wastes at the site, this requirement would not apply to the soils.
However, this requirement may apply to the treatment residuals from
the site, depending on whether they are listed or characteristic
wastes. Any hazardous waste would either be treated to levels
below the TCLP regulatory levels or be taken to a RCRA Subtitle C
hazardous waste landfill.
Contaminated media that is not listed or characteristic waste would
need to be disposed in a Florida Class I landfill, therefore the
FDER Class I and RCRA Subtitle D landfill regulations would be
applicable.
Other action-specific requirements that would be appropriate
are Department of Transportation Hazardous Materials Transportation
rules for off site transport, and National Air Quality Standards for
excavation. State action-specific requirements that would apply
are the Florida Ambient Air Quality Standards and the Florida Air
Pollution Rules.
44
-------
' \ - .
No chemical-specific ARARs are available for soil and there are no
location-specific ARARs.
No waiver from ARARs is necessary to implement any alternatives.
Long-Term Effectiveness and Permanence. Alternative 2 would remove
all waste to a permitted offsite landfill, thereby eliminating any
long-term risks of exposure at the site. This alternative also
offers a high degree of certainty that it will be executed
successfully and is considered to be an irreversible permanent
remedy. Alternative 3 employs an irreversible treatment process to
provide long-term effectiveness and permanence to reduce hazards
posed by all known wastes at the site. Alternative 4 utilizes
treatment to achieve slightly less long-term effectiveness. The
stabilization/solidification process does have a low potential to
leach contaminants in the future and therefore may not be as
permanent as the other two alternatives. However, this technology
has been demonstrated to be effective at similar sites and long-
term monitoring of the groundwater would detect any breakdown of
the treatment remedy. Alternative 4 would rely on institutional
controls to ensure future integrity of the solidified material, by
requiring deed restrictions.
Reduction of Toxicity, Mobility, or Volume. Alternative 2 would
reduce the toxicity, mobility, and volume of contaminants at the
site. This alternative would not utilize treatment; however, the
estimated 2500 cy of waste would be transported to a permitted
landfill offsite where mobility would be reduced by containing the
contaminated soil in a secure landfill. However, toxicity and
volume would not be reduced. Alternatives 3 and 4 use treatment or
fixation technologies to reduce the inherent hazards posed by the
soil contaminants at the site. These two alternatives would
satisfy the statutory preference for treatment as a principal
element, to the maximum extent practicable.
The stabilization/solidification process in Alternative 4
encapsulates the soil contaminated with heavy metals, reducing the
mobility of the metals. There is a small potential for the
fixation process not to maintain the contaminants in the chemical
bond in the long-term, thereby initiating risk of contaminants
migrating to the groundwater. Treatability tests would minimize
this possibility. The stabilization/solidification process in
Alternative 4 increases the soil volume by the addition of
cementing materials and/or additives. The increase in volume is
estimated to be fifteen to twenty-five percent of the original
waste material.
Soil washing in Alternative 3 uses chemical interactions to reduce
the toxicity, mobility or volume of the soil contaminants to levels
which are protective of groundwater. However, this technology has
not demonstrated full capability of attaining the cleanup goals.
Alternative 3 would require additional management of residuals.
45
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The treatment process for this alternative would reduce the volume
of contaminated soil by washing the contaminants from the soil into
a concentrated waste stream.' This smaller volume of waste contains
the finer soil particles, contaminants and some washwater. The
washwater would require treatment and the concentrated contaminated
fine soil would require treatment or offsite RCRA hazardous waste
disposal. The soil washing process in Alternative 3 would render
approximately 90% of the soil uncontaminated.
Short-term effectiveness. Alternative 2, 3, and 4 are expected to
be protective of human health and the environment throughout
construction and implementation. Similar risk exists for all
alternatives to workers, the community and the environment during
excavation and treatment or removal. Alternatives 2, 3, and 4
would involve implementing dust control measures during excavation
of the soils to prevent release of increased particulates into the
atmosphere.
Alternatives 2 and 4 would provide protectiveness in a relatively
short time, compared to Alternative 3. A construction period of
only one month for Alternative 2 and two to three months for
Alternative 4 would be required to achieve short-term protection.
Alternative 2 poses a risk during transportation of the
contaminated soil to the offsite facility and Alternatives 3 and 4
pose a risk during the treatment process. Careful implementation
of standard safety protocols would lessen this risk.
Alternative 3 is anticipated to have the least short-term
effectiveness. Alternative 3 would require the longest
implementation time of five to seven months. This alternative
poses a risk of accidental exposure to the soil washing additive.
Also, there is a risk the cleanup goals may not easily be met
during the soil washing, which would require additional washes and
additives. This would slow the process. Alternative 3 requires
treatability tests to determine effectiveness and optimal design,
prior to starting.
Implementation. Alternative 2 would not require specialized
materials, and equipment beyond common excavation equipment.
Alternative 2 is a proven technique and would not require
treatability studies. Prior to disposing offsite, this alternative
would require coordination with the landfill. Alternatives 2 and
3 would require less future O&M than Alternative 4 since the
contamination is removed from the site or the soils, respectively.
Alternatives 3 and 4 would both require specialized equipment,
materials, and labor, which is available from a variety of vendors.
There are more vendors available for stabilization/solidification
in Alternative 4 that have demonstrated effectiveness than for soil
washing in Alternative 3. The solidification process of
Alternative 4 can be conducted onsite in a suitable area which is
large enough for portions of the soil to be processed and allow for
46
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workers to operate the equipment. Alternative 3 would require, more
elaborate process equipment than Alternative 4, which would drive
up the cost. Treatability tests would be required for Alternatives
3 and 4 to ensure that the soil washing would remove the
contaminants to concentrations below the cleanup goals, and to
ensure the mixtures of fixation agents would prevent the
contaminants from leaching into the groundwater, respectively.
However, the nature of the contaminants and the characteristics of
the soil have been shown to be more responsive to the treatment
process in Alternative 4 than Alternative 3.
«*
Soil washing (Alternative 3) has been selected as the remedial
alternative at other Superfund sites; however, the cleanup goals
for these sites were higher than those for this site. Also, soil
washing was not shown to be as effective as stabilization/
solidification for the contaminants at the site in small scale
treatability tests and soil washing requires a larger area for the
process operation than the fixation alternative.
Cost. Alternative 2 is the most economical alternative with a
total present worth cost of $338,186. This alternative offers
similar protectiveness compared to the other alternatives and is a
proven technique. Alternative 4 has a total present worth cost of
$385,225. The higher cost of Alternative 4 is primarily due to the
O&M, which accounts for 40% of the total cost.
The soil washing process drives the high capital cost of $878,000
for Alternative 3 and the low O&M cost of $13,650 does not totally
replace the loss of money to capital outlay. This alternative's
total present worth cost of $891,650 is the least economical
without providing additional protectiveness.
It is assumed for all alternatives that construction would begin
within one year.
State Acceptance. The State of Florida, as represented by the
Florida Department of Environmental Regulation (FDER), has been the
support agency during the Remedial Investigation and Feasibility
Study process for the Standard Auto Bumper site. In accordance
with 40 CFR 300.430, as the support agency FDER has provided input
during this process. Based upon comments received from FDER, it is
expected that concurrence will be forthcoming; however, a formal
letter of concurrence has not yet been received.
Community Acceptance. The local Dade County Department of
Environmental Resources (DERM) has been involved with this site.
EPA has consulted DERM on the site and the alternatives. DERM and
EPA will continue to work together to provide the best remedial
action which minimizes the potential for impacts to the nearby
businesses and residents to the site. DERM has provided assurance
that the soil may be sent to a Florida Class I Landfill.
47
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During the 30-day public comment period, no comments were received
from the community. The public meeting at which EPA presented the
proposed plan was attended by three people. Overall, there has
been very little community interest at this site throughout the
Superfund process, even though over 400 proposed plans were sent to
the community, media, and government officials and newspaper
articles have highlighted this site. There is no indication the
public would not support the selected remedy.
10.0 SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the NCP,
the detailed analysis of alternatives and public and state
comments, EPA has selected a source control remedy for this site.
At the completion of this remedy, the risk associated with this
site has been calculated at less than 10"6 for carcinogens and less
than one for nonearcinogens, which is determined to be protective
of human health and will be protective of the environment. The
total present worth cost of the selected remedy, Alternative 2, is
estimated at $338,186.
A. SOURCE CONTROL
Source control remediation will address the contaminated soils at
the site. Source control shall include excavation of contaminated
soils, transportation to a Florida Class I landfill, backfilling
the excavated area and site monitoring.
A.I. The major components of the source control to
be Tmplemented includes
• Complete excavation from the surface soils of
soil contaminated with total chromium,
hexavalent chromium, or nickel above 519
mg/kg, 52 mg/kg, and 370 mg/kg, respectively,
or interface with the water table
(approximately 2500 cubic yards).
• Offsite disposal of the excavated soil at a
Florida Class I landfill,
• Backfilling the excavated areas with clean fill, and
• Groundwater monitoring for the contaminants of
concern for up to 5 years.
A.2. Performance Standards.
The performance standards for this component of the selected remedy
include, but are not limited to, the following excavation and
disposal standards:
48
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a. Excavation Standards
Excavation shall continue until the remaining
soil achieves the maximum levels below or
until the water table is reached. All
excavation shall comply with ARARs, including
but not limited to the Clean Air Act, Florida
Air Pollution Rules, Florida Ambient Air
Quality Standards, Subtitle D requirements,
and DOT requirements. All work at the site
shall comply with OSHA requirements. Testing
methods approved by EPA or that are the best
available technology shall be used to
determine if the maximum nickel and chromium
concentration levels shown below have been
achieved in the remaining soil.
Total Chromium 519 mg/kg
Hexavalent Chromium 52 mg/kg
Nickel 370 mg/kg
The soil cleanup levels are necessary to
ensure that migration of all the contaminants
into the groundwater is minimized and were
developed during the Risk Assessment based on
risk to human health and the environment (the
groundwater). Cleanup to these standards will
ensure that contaminants do not continue to
migrate into the groundwater and human health
risks are reduced to protective levels.
b. Disposal Standards
Transportation of the contaminated soil will
be conducted in accordance with DOT
regulations. The excavated soil shall be
transported from the site to the Class I
landfill (liner and leachate collection) using
approved transportation routes for safe
transport. All soil to be disposed of off site
must meet the following criteria:
• Non-hazardous waste as defined by the TCLP
test (40 CFR 261)
The landfill must meet FDER Class I landfill
regulations.
B. COMPLIANCE TESTING
Groundwater monitoring shall be conducted at this site. After
demonstration of compliance with Performance Standards, the site
49
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groundwater shall be monitored for the contaminants of concern for
up to five years to verify that the removal of the contaminated
soil in excess of those levels set forth in paragraph A. 2 does
minimize the impact these contaminants have on the quality of the
underlying aquifer. If monitoring data indicates the soils
continue to be a source of groundwater contamination after
implementation of the remedial action, EPA will re-evaluate the
effectiveness of the remedy.
Because this remedy will not result in hazardous substances
remaining onsite above health-based levels, the five-year review
will not be necessary at this site.
11.0 STATUTORY DETERMINATIONS
EPA's primary responsibility at Superfund Sites is to select
remedial actions that are protective of human health and the
environment. CERCLA also requires that the selected remedial
action for the site comply with applicable or relevant and
appropriate environmental standards established under Federal and
State environmental laws, unless a waiver is granted. The selected
remedy must also be cost-effective and utilize permanent treatment
technologies or resource recovery technologies to the maximum
extent practicable. The statute also contains a preference for
remedies that include treatment as a principal element. The
following sections discuss how the selected remedy for contaminated
soils at the Standard Auto Bumper site meets these statutory
requirements.
Protection of Human Health and Environment:
The selected remedy protects human health and the environment by
reducing levels of contaminants in the source of contamination, the
soils, through excavation and containment. Eliminating the source
of contamination will reduce levels of contaminants migrating from
the soils into the groundwater, and reduce the threat to levels
below 10"6 for carcinogens and a Hazard Index of below one for
nonearcinogens for future child residents ingesting contaminated
soil. No unacceptable short-term risks or cross-media impacts will
be caused by implementation of the remedy.
Compliance with ARARs
All ARARs will be met by the selected remedy.
Chemical-Specific ARARs. No chemical-specific ARARs apply to
contaminated soils.
Action-Specific ARARs. Federal action-specific ARARs include the
National Ambient Air Quality Standards under the Clean Air Act.
State action-specific ARARs include the Florida Air Pollution Rules
FAC 17-2.1 and Florida Ambient Air Quality Standards FAC 17-2.3.
50
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RCRA Land disposal restrictions (LDRs) are not applicable or
relevant and appropriate. The contaminated soil at the site is not
a listed or characteristic RCRA waste. In studies conducted for
the FS, the soil did not exceed the regulatory TCLP criteria for
chromium and lead (no regulatory level has been established for
nickel).
Nickel, chromium, and lead are listed CERCLA hazardous substances
as defined by CERCLA 40 CFR 302.4. However, because the soil is a
RCRA non-hazardous waste it may be disposed in a permitted solid
waste landfill. Therefore the RCRA Subtitle D requirements and
FDER Class I requirements will apply to the landfill and DERM
requirements for soil disposal in a local landfill will also apply.
DOT requirements will be appropriate to consider during transport
of the contaminated soil to the landfill.
Location-Specific ARARs. No location specific ARARs are applicable
or relevant and appropriate for the site.
Cost-Effectiveness
After evaluating all of the alternatives which satisfy the two
threshold criteria above, EPA has concluded the selected remedy
affords the highest level of overall effectiveness proportional to
its cost. Section 300.430(f)(1)(ii)(D) of the NCP also requires EPA
to evaluate three out of the five balancing criteria: long-term
effectiveness and permanence; reduction of toxicity, mobility or
volume through treatment; and short-term effectiveness, to
determine overall effectiveness. Cost-effectiveness is determined
by evaluating these balancing criteria to determine overall
effectiveness. Overall effectiveness is then compared to cost to
ensure that the remedy is cost-effective. The selected remedy
provides for overall effectiveness in proportion to its cost.
The estimated total present worth cost for the selected remedy is
$338,186.
Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the M^^imnm
Extent Practicable ("HEP")
EPA believes the selected remedy represents the maximum extent to
which permanent solutions can be utilized in a cost-effective
manner for the Standard Auto Bumper site. After evaluating the
alternatives that are protective of human health and the
environment and comply with ARARs, EPA has determined that the
selected remedy provides the best balance in terms of the remaining
criteria.
The selected remedy includes offsite disposal of untreated
51
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contaminated soil which does not satisfy the preference for
treatment as a principal element. EPA has determined however that
the benefits of this alternative, as determined by the balancing
and modifying criteria, outweigh the disadvantage of not employing
treatment. Treatment was found to be unnecessary for the waste at
this site, due to the non-hazardous nature of the contaminated
soil, as defined by RCRA. However, a cleanup action is necessary
to reduce the risk to human health and the environment to
acceptable levels. In making the determination for or against
offsite disposal, the modifying criteria of state acceptance was
considered (Section 300.430(f)(1)(ii)(E) of the NCP. In light of
this consideration, EPA decided after evaluating all nine criteria
to select excavation and offsite disposal for this site.
This selected remedy provides protectiveness; attains ARARs; offers
long-term effectiveness and permanence; and reduces toxicity,
mobility, or volume of contaminants at the site. Excavation and
offsite disposal requires the simplest equipment, the shortest
implementation time, and is the most cost effective of all the
alternatives.
This remedy is consistent with future response actions that may be
considered for the site by addressing the source of contamination
at the site. Source control reduces or eliminates the level of
further action at the site that would be necessary for OU f2,
groundwater.
Preference for Treatment as a Principal Element
The statutory preference for treatment is not satisfied by the
selected remedy; however, excavation and offsite disposal utilizes
a cost-effective method to address the threats posed by conditions
at the site. The cleanup objectives of the selected remedy address
the health and environmental threats at the site: direct contact
with contaminated surface soil and migration of soil contaminants
to the groundwater. ..The remedy will reduce the toxicity, mobility,
and volume of the co'ntaminants at the site and will provide long-
term effectiveness and permanence.
12.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan was released for public comment during August and
September 1992. Three changes to the Proposed Plan have been made
since its release and will be described in this section.
The Proposed Plan identified Alternative 4, excavation of
contaminated soil, onsite stabilization/solidification, and
groundwater monitoring, as the preferred alternative. One of the
other alternatives (Alternative 2) presented in the Proposed Plan
and in the FS involved excavation of contaminated soils and offsite
disposal. The original preference for Alternative 4 was based in
part on the preference for employing an onsite treatment
52
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alternative at a site. However, during the public comment period,
staff at PDER voiced a preference for Alternative 2 because this
alternative did not require the long-term O&M that Alternative 4
required. Groundwater monitoring for up to 30 years was necessary
to ensure the integrity of the stabilization/solidification
treatment in Alternative 4. Upon re-evaluation of the two
alternatives, the offsite disposal remedy was determined to be a
more reliable, long-term effective, permanent, implementable, and
cost-effective remedy for the estimated quantity of contaminated
soil at the Standard Auto Bumper site than the
stabilization/solidification remedy originally preferred.
The Proposed Plan did not state that institutional controls would
be required for Alternative 4 to ensure the integrity of the
solidified material. EPA decided that deed restrictions would
provide more effective long-term protectiveness for this
alternative and has included it in the description of Alternative
.4.
Lastly, the Proposed Plan stated a cleanup goal for nickel only.
EPA and FOER decided that a cleanup goal was also necessary for
chromium to ensure this contaminant was reduced to protective
levels during the implementation of the remedy.
53
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APPENDIX A
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RESPONSIVENESS SUMMARY
This summary presents all of the Agency's responses to comments
received from the community, local officials, and potentially
responsible parties (PRPs) for the Standard Auto Bumper site
operable unit one, soils.
A. OVERVIEW
At the start of the public comment period, EPA released its
selection for the preferred alternative via the media and the
proposed plan. EPA's recommended alternative was excavation of
contaminated soil, onsite stabilization/solidification, and
groundwater monitoring. Based on the comments received from the
State of Florida and documented herein, EPA re-evaluated the
alternatives and selected another alternative. The alternative
specified in this Record of Decision involves excavation of
contaminated soil and offsite disposal.
Judging from the comments received from the residents in the
community during the public comment period, the community would not
be adverse to excavation and offsite disposal. The local citizens
did not voice objections to any of the alternatives.
B. BACKGROUND ON COMMUNITY INVOLVEMENT
Community interest in the Standard Auto Bumper site has been very
limited dating back to the start of the Remedial Investigation when
EPA held a public availability session at the Henry M. Filer
Middle/Community School. The meeting, held on January 10, 1991,
was announced in the local newspaper and an EPA fact sheet. The
only person from the community who attended the meeting, was an
employee of the Standard Auto Bumper Corporation. EPA has made
information on the site available at the local library and the
Regional office in Atlanta, Georgia. These files are updated as
new material is generated concerning the site.
During the Remedial Investigation/Feasibility Study, public
interest remained at the same low level. Calls the Agency received
regarding the site were from firms conducting environmental
assessments on nearby properties. These callers wanted to know the
extent of contamination at the site. The Agency's response was
that contaminated soil was found on properties adjacent to the
Standard Auto Bumper property and that the extent of groundwater
contamination had not been ascertained.
C. SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD
AND AGENCY RESPONSES
EPA mailed the Proposed Plan to approximately 450 people in the
media, community, and government on August 3, 1992. The public
comment period on the Feasibility Study and Proposed Plan for the
site was held from August 7 to September 6, 1992. All comments
from the community were received during the public meeting on
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August 18, 1992, at the Henry M. Filer Middle/Community School in
Hialeah, Florida. The purpose of the meeting was to present EPA's
preferred alternative. This meeting was attended by three
citizens. Part I of this section addresses the community's
questions; Part II addresses the State's comments received after
the public meeting. No comments have been received from the PRP.
A summary of the comments or questions and EPA's response to those
comments or questions is set out below.
Part I - Summary and Response to Local Community Concerns
1. Who pays for the cleanup?
EPA Response: The EPA Superfund provides the money; however,
the fund is reimbursed. EPA recovers the costs from the PRP,
Standard Auto Bumper, through the justice system.
2. At the public meeting a student asked how stable the
solidified soils will be and who's responsible for monitoring
the material.
EPA Response: It was explained that EPA performed a
treatability study on the contaminated soil and successfully
solidified the material as shown by the Toxicity
Characteristic Leaching Procedure. This procedure measures
the levels of contaminants leaching from the hardened
monolith. The leach levels for the solidified soil were below
regulatory levels, indicating the solidification was
effective. However, EPA will perform another treatability
test prior to the cleanup. EPA further explained
stabilization/solidification is a common and reliable remedy
for metal-contaminated soil. The process solidifies the soil
into a mass very similar to concrete, preventing the soil
contaminants from leaching into the groundwater. EPA
considers this technology to be protective of the groundwater
at the site. It was added that solidification will enhance
natural attenuation of groundwater contamination, and
groundwater sampling has indicated much lower levels of
contaminants during subsequent sampling events. In conclusion,
EPA explained that should this remedy be selected, they will
monitor the remedy for the first year following cleanup and
then the State will assume responsibility.
Part II - Summary and Response to the State of Florida's Concerns
1. Staff at the Florida Department of Environmental Regulation
(FDER) disagreed with EPA's preferred alternative of
excavation, stabilization/solidification, and groundwater
monitoring. FDER staff suggested that the long-term
monitoring was excessive and that this requirement could be
avoided by selecting a comparable alternative, excavation and
offsite disposal. This alternative did not require long-term
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operation and maintenance (O&M).
EPA Response: The alternative EPA recommended at the public
meeting (excavation, onsite stabilization/solidification, and
groundwater monitoring) was favored mainly due to the
Superfund statutory preference to employ treatment to reduce
toxicity, mobility, or volume as a principal element.
However, EPA determined that the staff at the State had valid
concerns regarding the burdensome long-term O&M commitments
necessary for the stabilization/solidification alternative.
EPA resolved that at this site it was not preferable to
utilize treatment to reduce toxicity, mobility, or volume,
because the soil is not a hazardous waste as defined by the
Resource Conservation and Recovery Act (RCRA) and is a
relatively small volume, approximately 2500 cubic yards.
Excavation and offsite disposal was then selected as a remedy
that utilizes permanent technologies and alternative treatment
technologies, to the maximum extent practicable for this site.
Up to five years of groundwater monitoring will be required
following offsite disposal. Excavation and offsite disposal
was the remedy selected in the ROD, which contains further
details of the process for selecting the remedial alternative.
D. REMAINING CONCERNS
EPA is mainly concerned with the abatement. of any groundwater
contamination by cleaning up the soils, the source of the
contamination. Future testing of the groundwater during the RI/FS
for operable unit two, groundwater, will define the nature and
extent of any groundwater contamination. EPA is confident that the
selected alternative will minimize the need for groundwater pumping
and treatment. EPA plans to keep the public and local officials
informed of the activities that the Agency is undertaking at the
site along with any new information that may involve the site. EPA
will issue another Proposed Plan for the preferred groundwater
alternative for oper-able unit two.
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APPENDIX B
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fi &.1.1 Qn-Site Worker Assumptions
Exposure factors chosen for the on-site worker in conducting this exposure
assessment come from the EPA reference documents cited earlier and are listed
below.
. Based upon information in the EPA document, Exposure Factors Handbook
(EPA 1989b), the recommended BU for adults is 70 kg. This, factor is
also a Standard Default Exposure Factor for Commercial/Industrial Land
use according to EPA guidance. Therefore, this factor is selected for
use in assessing the exposure to on-site workers.
• The Standard Default Exposure Factor for Commercial/Industrial Land use
in determining the exposure frequency (EF) is 250 days/year according
to EPA guidance. Therefore, this factor is selected for use in
assessing the exposure to on-site workers.
» The Standard Default Exposure Factor for Commercial/Industrial Land use
in determining the exposure duration (ED) is 25 years according to EPA
guidance. Therefore, this factor is selected for use in assessing the
exposure to on-site workers.
• For noncarcinogenic chemicals, average time (AT) is calculated by
averaging 365 days/year over a period of 25 years to yield an AT of
9,125 days. For carcinogens, intakes are calculated by averaging the
total cumulative dose over a 70-year lifetime, yielding a carcinogenic
AT of 25.550 days.
• Available exposed skin area for an onsite worker was assumed to be
limited to the head and hands. According to the Exposure Factors
Handbook. March 1990, this area for an adult male would be
approximately 2,000 cm2.
All exposure parameter values for the onsite worker scenario are listed in Table
6-1. The intake factor formulas for each pathway-specific exposure and the
intake factor value is included in Table 6-2.
36
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TABLE 6-1
TES VIII WORK ASSIGNMENT NO. C04094
FINAL BASELINE RISK ASSESSMENT FOR THE
STANDARD AUTO BUMPER SITE
HIALEAH, DADE COUNTY, FLORIDA
PARAMETERS FOR CALCULATION OF INTAKE FACTOR FOR ONSITE WORKER
PARAMETER
BODY WEIGHT (BW)
EXPOSURE TIME (ET)
EXPOSURE FREQUENCY (EF)
EXPOSURE DURATION (ED)
INHALATION RATE (IR)
SOILS INGESTION RATE (IRSS)
SKIN SURFACE AREA (SA)
SOIL/SKIN ADHERENCE FACTOR (AF)
ABSORPTION FACTOR (ABS)
NONCARCINOGENIC AVERAGING TIME (NAT)
CARCINOGENIC AVERAGING TIME (CAT)
CONVERSION FACTOR (CF)
UNITS
kg
Hours
Days/Year
Years
m3/Workday
mg/Day
cm2
mg/cm
No Units
Days
Days
kg/rag
VALUE
70
8
250
25
20
50
2,000
1.0
0.001 (for Inorganics)
9,125
25,550
1/1.000.000
SOURCE
SDEF1
SDEF1
SDEF1
SDEF1
SDEF1
SDEF1
Professional
Judgement
NIR4G1
NIR4G3
RAGS*
RAGS*
RAGS*
1. Human Health Evaluation Manual, Supplemental Guidance: "Standard Default Exposure Factors",
March 25, 1991.
2. Professional Judgement justification is discussed in Section 6.4.1.
3. New Interim Region IV Guidance, February 11, 1992.
4. Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A), Interim Final,
December 1989.
37
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j /. i 9 Site Visitor
For purposes of assessing potential health risks associated with exposure to a site
visitor, the site visitor is assumed to be a youth between the ages of 9 and 18. The
exposure assumptions are itemized below.
• Based upon information in the EPA document, Exposure Factors Handbook (EPA
1989b) the average BW for male youths between the ages of 9 and 18 is 50.5
kg. Based on professional judgement, this BW will be utilized for the
site visitor in assessing exposure.
• The site visitor is assumed to visit the site for 8 hours/visit. This
assumption is a professional judgement based upon the size of the site and
the general composition of the site layout and features. Based on
professional judgement, this EF will be utilized for the site visitor as
the ET in assessing exposure.
• The site visitor is assumed to visit the site 1 day/week for 9 months/year
or 39 days/year. Based on professional judgement, EF will be utilized for
the site visitor in assessing exposure.
• The ED for the ages 9 to 18 is 10 years.
• For noncarcinogenie chemicals, AT is calculated by averaging 365 days/year
over a period of 10 years to yield an AT of 3,650 days. For carcinogens,
intakes are calculated by averaging the total cumulative dose over a 70-
year lifetime, yielding a carcinogenic AT of 25,550 days.
/
• Available exposed skin area for the site visitor was assumed to be limited
to the head, hands, forearms, and lower legs. According to the Exposure
Factors Handbook. March 1990, this area for an adult male would be
approximately 5,300 cm2.
All values for the site visitor scenario is listed in Table 6-3. The intake factor
formulas for each pathway-specific exposure and the intake factor value is included
in Table 6-4.
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TABLE 6-3
TES VIII WORK ASSIGNMENT NO. C04094
FINAL BASELINE RISK ASSESSMENT FOR THE
STANDARD AUTO BUMPER SITE
HIALEAH, DADE COUNTY, FLORIDA
PARAMETERS FOR CALCULATION OF INTAKE FACTOR FOR SITE VISITOR
PARAMETER
BODY WEIGHT (BW)
EXPOSURE TIME (ET)
EXPOSURE FREQUENCY (EF)
EXPOSURE DURATION (ED)
INHALATION RATE (IR)
SOILS INGESTION RATE (IRSS)
SKIN SURFACE AREA (SA)
SOIL/SKIN ADHERENCE FACTOR (AF)
ABSORPTION FACTOR (ABS)
NONCARCINOGENIC AVERAGING TIME (NAT)
CARCINOGENIC AVERAGING TIME (CAT)
CONVERSION FACTOR (CF)
UNITS
kg
Hours
Days/Year
Years
mJ/Workday
mg/Day
cm2
rag/era
No Units
Days
Days
kR/mR
VALUE
50.5
8
39
10
20
100
5 , 300
1.0
0.001 (for Inorganics)
3,650
25,550
1/1.000.000
SOURCE
Professional
Judgement
Professional
Judgement
Professional
Judgement
Professional
Judgement
Professional
Judgement
Professional
Judgement
Professional
Judgement
NIR4C2
NIR4G2
RAGS3
RAGS1
RAGS1
1. Professional Judgement Justification is discussed in Section 6.4.1.
3. New Interim Region IV Guidance, February 11, 1992.
4. Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A), Interim Final,
December 1989.
4.0
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fc L 1.3 Hypothetical Residential Exposure Assumptions
Exposure factors chosen for the hypothetical future residents in conducting the
hypothetical future resident assumptions will consider both an adult and a child
scenario. The adult scenario will be considered for all exposure pathways cited in
Section 6.1.4- The child scenario will be considered for the incidental ingestion
and dermal contact of soils pathway as these are considered the most significant
pathway concerning children. This exposure assessment is derived from the EPA
reference documents cited earlier and are as follows:
. The body weights for the adult and child is 70 kg and 15 kg, respectively,
in accordance with the guidance in EPA's Human Health Evaluation Manual.
Supplemental Guidance. "Standard Default Exposure Factors' (1991).
. The EF to be utilized according to the EPA's Risk Assessment Guidance for
Superfund. Vol""an Health Evaluation Manual (Part A) Interim
Final (1989), the 90th percentile national upper-bound time at a single
residence is 30 years. EPA guidance states that the 90th percentile
values should be used if 95th percentile values are unavailable.
Therefore, this value will be utilized as the ED in assessing exposure to
the hypothetical future resident. The ED for the child will be 6 years.
• Available exposed skin area for the adult hypothetical future residents
will be assumed to be limited to the head, hands, forearms and lower legs.
According to the Exposure Factors Handbook. March 1990, this area for an
adult nale would be approximately 5,300 cm2. The child will include head,
hands, arms and legs which would be approximately 5,000 cm2.
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For noncarcinogenic chemicals, the adult scenario's AT is calculated by
averaging 365 days/year over a period of 30 years to yield an AT of 10,950
days. For carcinogens, intakes are calculated by averaging the total
cumulative dose over a 70-year lifetime, yielding a carcinogenic AT of
25,550 days.
For noncarcinogenic chemicals, AT for the child scenario is calculated by
averaging 365 days/year over a period of 6 years to yield an AT of 2,190
days. Carcinogenic intakes will not be considered in the child scenario
because the purpose in assessing carcinogenic risk is to evaluate the long-
term effects of exposure. Further, slope factors are based upon 70 years
of exposure and therefore is inappropriate for the evaluation of children.
All values for the hypothetical future residents are listed in Tables 6-5 and 6-7.
The intake factor formulas for each pathway-specific exposure and the intake factor
value is included in Tables 6-6 and 6-8.
43
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TABLE 6-5
TES VIII WORK ASSIGNMENT NO. C04094
BASELINE RISK ASSESSMENT
STANDARD AUTO BUMPER SITE
HIALEAH, DADE, FLORIDA
PARAMETERS FOR CALCULATION OF INTAKE FACTOR FOR ADULT HYPOTHETICAL FUTURE RESIDENT
PARAMETER
BODY WEIGHT (BU)
EXPOSURE TIME (ET)
EXPOSURE FREQUENCY (EF)
EXPOSURE DURATION (ED)
INHALATION RATE (IR)
SOILS INGESTION RATE (IRSS)
SKIN SURFACE AREA (SA)
SOIL/SKIN ADHERENCE FACTOR (AF)
ABSORPTION FACTOR (AfiS)
NONCARCINOGENIC AVERAGING TIME (NAT)
CARCINOGENIC AVERAGING TIME (CAT)
CONVERSION FACTOR (CF)
UNITS
kg
Hours
Days/Year
Years
mJ/Workday
rag/Day
cm2
mg/cm2
No Units
Days
Days
kR/mR
VALUE
70
24
350
30
20
100
5,300
1.0
0.001 (for Inorganics)
10,950
25,550
1/1,000,000
1. Human Health Evaluation Manual, Supplemental Guidance: "Standard Default Exposure Factors",
2. Professional Judgement Justification Is discussed In Section 6.4.1.
3. New Interim Region IV Guidance, February 11, 1992*
4. Risk Assessment Guidance for Super fund, Volume I, Human Health Evaluation Manual (Part A),
December 1989.
SOURCE
SDEF1
SDEF1
SDEF1
SDEF1
SDEF1
SDEF1
Professional
Judgement
Professional
Judgement
NIR4G1
RAGS*
RAGS*
RAGS*
March 25, 1991.
Interim Final,
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TABLE 6-7
TES VIII WORK ASSIGNMENT NO. C04094
FINAL BASELINE RISK ASSESSMENT FOR THE
STANDARD AUTO BUMPER SITE
HIALEAH, DADE COUNTY, FLORIDA
PARAMETERS FOR CALCULATION OF INTAKE FACTOR FOR CHILD HYPOTHETICAL FUTURE RESIDENT
PARAMETER
BODY WEIGHT (BW)
EXPOSURE TIME (ET)
EXPOSURE FREQUENCY (EF)
EXPOSURE DURATION (ED)
INHALATION RATE (IR)
SOILS INGESTION RATE (IRSS)
SKIN SURFACE AREA (SA)
UNITS
kg
Hours
Days/Year
Years
m'/Workday
mg/Day
cm2
VALUE
15
24
350
6
20
200
5,000
SOURCE
SDEF1
SDEF1
SDEF1
SDEF1
SDEF1
SDEF1
Professional
SOIL/SKIN ADHERENCE FACTOR (AF) mg/cm2
ABSORPTION FACTOR (ABS) No Units
NONCARCINOGENIC AVERAGING TIME (NAT) Days
CONVERSION FACTOR (CF) kg/rag
1.0
0.001 (for Inorganics)
2,190
1/1.000.000
Judgement
Professional
Judgement
NIR4GJ
RAGS*
RAGS*
1. Human Health Evaluation Manual, Supplemental Guidance: "Standard Default Exposure Factors", March 25, 1991.
2. Professional Judgement-justification is discussed in Section 6.4.1.
3. New Interim Region IV Guidance, February 11, 1992
4. Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A), Interim Final,
December 1989.
-------
APPENDIX C
-------
r»
P/-'
Gasoline Spill
(•/G
Br.
ppre Cd
<77 ppm Hg
<155 ppm
>
TZil ':r
<100 ppn
<100 ppa
<50,000 ppm
i ' r
0.' :
Cil Spill
J!3t;D fO?. SPZCI-IC 5:Tv.'.
^..i.IiiS OF SOIL TO BE DISPOSED Or K.1/.
-.'- ALTSPNATIVES.
:LS MUST NOT BE A IiA7.A?.I;C-.'J l/AsTS A: ..
•! (0/G) pay fca iv:/-aa?;-d ti :v:
Art as.
(Total Recoverable P^troJeun Hydroc = rb.-/..
•"=rdous wastes nu^t b-3 disposed c5 d :.
'•i'.^r cont.ajninateci t'.ils viJ.l b>i :V;31 •.!'•".i
' .- THE
•;FS 261.
. D: Velllisid
.. Ksthod S073.
•- ?o facility.
:'.-' disposal at
l i •
POOR QUALITY
ORIGINAL
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