United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-93/147
August 1993
Superfund
Record of Decision:
Peak Oil/Bay Drum
(Operable Unit 2), FL
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R04-93/147
3. Recipient's Accession No.
Title and Subtitle
SUPERFUND RECORD OF DECISION
Peak Oil/Bay Drum (Operable Unit 2) , FL
Third Remedial Action
5. Report Date
08/09/93
6.
7. Authors)
8. Performing Organization Rept. No.
9. Performing Organization Name and Address
10 Pro|ect Taskwork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report A Period Covered
800/800
14.
15. Supplementary Notes
PB94-964032
16. Abstract (Limit: 200 words)
The 18.8-acre Peak Oil/Bay Drum (Operable Unit 2) site is a former used oil refinery in
Brandon, Hillsborough County, Florida. Land use in the area is predominantly
industrial and undeveloped, with three wetlands areas located adjacent to the site.
The nearest residential area is located 0.3 miles east of the site. Although not
utilized currently, onsite ground water is classified as a class II aquifer; and
therefore, is a viable source of ground water for future consumption. From 1954 to
1980, the 4-acre Peak Oil facility used an acid/clay purification and filtration
process to purify and re-refine waste oil and lubrication fluids. Waste oil accepted
at the facility for re-refining consisted primarily of used auto and truck crankcase
oil, with some hydraulic oil, transformer oil and other waste oil. The process
generated a low-pH sludge and oil saturated clay, which was stored over the life of the
site in.three impoundment areas (lagoons 1, 2, and 3); lagoons 1 and 3 were later
backfilled. In 1980, the company discontinued the re-refining process and shifted to
filtering and blending the waste oil for resale. Several company employees reported
onsite leaks and spills and that waste continued to be stored onsite. From 1962 to 1982
the Bay Drums facility was operated as a drum reconditioning facility. Approximately 2
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Peak Oil/Bay Drum (Operable Unit 2), FL
Third Remedial Action
Contaminated Medium: gw
Key Contaminants: VOCs (benzene, PCE, TCE, toluene, xylenes), other organics (PAHs),
metals (arsenic, chromium, lead)
b. Identifiers/Open-Elided Terms
c. COSATI Field/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None .
21. No. of Pages
76
22. Price
(See ANSI-Z39.18)
See Instructions on Reveres
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R04-93/147
Peak Oil/Bay Drum (Operable Unit 2), FI
Third Remedial Action
Abstract (Continued)
acres of the 14.8-acre site were used for drum reclaiming activities; however, almost the
entire site was used for drum storage. A one-acre wetland that originally existed on the
southern portion of the site was partially dried from berms and used for storage of drums
and discharge of waste over the years. From 1974 to 1978, the site was owned and operated
by Tampa Steel Drums, during which period the volume of drums reconditioned increased. In
1975, storage of drums was observed along the edge of the onsite wetland, and by 1977, the
wetland had been backfilled, presumably with soil from an area of the site where a new
pond was visible. Drainage from the sites was diverted to the larger offsite wetland. In
1978, the filled wetland area was developed into a wash water holding pond, which is known
to have received waste from drum reconditioning activities. In 1982, drum reconditioning
activities ceased. From 1984 to 1986, the Bay Drums site was operated by Resource
Recovery Associates, during which time waste roofing shingles were deposited on the ground
over most of the site to heights ranging from three to nineteen feet. In 1989, EPA
removed, and deposited offsite 70,000 yd^ of shingles; the pile currently lies on
Hillsborough County property. In 1990, EPA conducted another removal action for the
contaminated soil, drums, and bags of pesticides from the site. Two other RODs signed in
1993 address source remediation at the Peak Oil/Bay Drums sites, as OUs 1 and 3,
respectively. This ROD addresses ground water contamination at both sites to meet State
and Federal drinking water standards, as OU2. A future ROD will address wetlands
contaminated by the Peak Oil/Bay Drums site, as OU4. The primary contaminants of concern
affecting the ground water are VOCs, including benzene, PCE, TCE, toluene, and xylenes;
other organics, including PAHs; and metals, including arsenic, chromium, and lead.
The selected remedial action for this site includes decommissioning two production wells;
extracting and pretreating ground water, as necessary, with an oil/water separator; air
stripping onsite to remove VOCs; carbon polishing onsite by activated liquid phase carbon
to remove SVOCs and other organics; discharging treated-water that is not returned to the
Peak Oil site for use in the OU1 soil flushing/bioremediation system to a POTW; and
monitoring ground water. The selected remedial action is contingent upon the ability of
the air stripping and carbon polishing to meet pretreatment requirements for a local POTW;
if the requirements are not met, chemical precipitation for the treatment of metals and
discharge by spray irrigation, recharge, or surface water may be employed. The estimated
present worth cost for this remedial action is $5,632,000, which does not include the
contingency cost.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific ground water cleanup goals are based on State and Federal MCLs and
health-based standards, and include arsenic 50 ug/1; benzene 1 ug/1; chromium 100 ug/1;
lead 15 ug/1; naphthalene 100 ug/1; PCE 3 ug/1; toluene 1,000 ug/1; total xylenes 20 ug/1.
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RECORD OF DECISION
OPERABLE UNIT 2
AREA-WIDE GROUND WATER
PEAK OIL/BAY DRUMS SITE
Brandon, Hillsborough County, Florida
Prepared By:
Environmental Protection Agency
Region IV
Atlanta, Georgia
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RECORD OF DECISION
PEAK OIL/BAY DRUMS GROUNDWATSR
OPERABLE UNIT TWO
PEAK OIL/BAY DRUMS KPL SITE
DECLARATION
SITE NAME AND LOCATION
Peak Oil/Bay Drums Superfund Site
Brandon, Hillsborough County, Florida
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
Operable Unit Two at the Peak Oil/Bay Drums Site in Brandon,
Hillsborough County, Florida, which was chosen in accordance with
the Comprehensive Environmental Response Compensation and Liability
Act of 1980 (CERCLA) , as amended by the Superfund Amendments
Reauthorization Act of 1986 (SARA), and, to the extent practicable,
the National Oil and Hazardous Substances Pollution Contingency..
Plan (NCP) . This decision is based on the administrative record"
file for this site.
The State of Florida, as represented by the Florida Department of
Environmental Protection (FDEP) , has been the support agency during
the Remedial Investigation and Feasibility Study process for the
Peak Oil/Bay Drums Site. In accordance with 40 CFR 300.430, as the
support agency, FDEP has provided input during this process and
although a formal letter of concurrence has not yet been received,
concurrence is expected.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision (ROD) , may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE REMEDY
The remedy selected by EPA for the Peak Oil/Bay Drums Site will be
conducted in four separate operable units. Operable Unit One will
address the source of contamination at the Peak Oil Site through
the treatment of contaminated soils and the ash pile located on the
site. Operable Unit Two, which is addressed in this Record of
Decision, will address the appropriate remediation for the
groundwater of the southern surficial aquifer and the Upper
Floridan Aquifer at the Peak Oil and Bay Drums Sites. Operable
Unit Three will address the source of contamination at the Bay
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Drums Site through the treatment of contaminated soils on the site.
Operable Unit Four will address the appropriate remediation for the
surrounding wetlands at the Peak Oil, Bay Drums and Reeves
Southeastern Sites.
The goal of the Operable Unit Two remedial action is to restore
groundwater at the Peak Oil/Bay Drums Site to meet Federal and
State drinking water standards. Both the southern surficial
aquifer and the Upper Floridan Aquifer are included in the state-
wide classification of potential future sources of drinking water.
Based upon information obtained during the remedial investigation,
and the careful analysis of all alternatives, EPA believes that the
selected remedy will achieve this goal.
Prior to implementing the groundwater remedy, as the first phase of
remedial design, the two production wells located on the Peak Oil
and Bay Drums sites, Wells F2 and F3, will be decommissioned. The
two production wells will be decommissioned and two new Floridan
monitor wells will be installed near the locations of F2 and F3.
Upon completion of the new monitor wells, all Floridan aquifer
wells at the sites will be sampled on a quarterly basis to evaluate
the level of contamination in the Upper Floridan aquifer.
9.1.1 The maior components of the qroundwater remedy for the-
southern surficial aquifer and the Upper Floridan Aquifer include;
o Groundwater extraction of both the surficial and Upper
Floridan aquifer via extraction wells.
o Implementation of the Peak Oil source control remedy
outlined in the Peak Oil/Bay Drums Record of Decision -
Operable Unit 1.
o Air stripping for removal of VOCs.
o Carbon polishing for removal of semi-volatiles and other
organic materials.
o Discharge to POTW. Groundwater will be treated to meet
Federal and State drinking water standards and/or
pollutant limits set by the local publicly owned
treatment works (POTW) prior to discharge. The treated
water will be conveyed via discharge piping to connect to
a manhole for ultimate discharge to the POTW. A permit
from the POTW will have to be obtained in order to
discharge the treated groundwater into its system.
o Groundwater monitoring.
As a contingency, if necessary, chemical precipitation for the
treatment of metals and alternate discharge methods are outlined in
the Selected Remedy section of this ROD.
ii
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The total present worth cost of the selected remedy, Alternative 3D
for the surficial aquifer and a modified Alternative 2 for the
Upper Floridan aquifer, as presented in the Feasibility Study, is
estimated at $4,132,000. This cost does not reflect contingency
costs and the cost of discharging treated water from the Upper
Floridan aquifer to the POTW. In the event that the contingency
plan must be implemented, the overall cost of the remedy is
estimated to increase by $500,000. The cost of discharging treated
Upper Floridan water to the POTW is estimated to increase the cost
of the remedy as much as $1,500,000, bringing the total estimated
cost of the remedy (without contingencies) to $5,632,000.
STATUTORY DETERMINATION
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. The remedy utilizes permanent
solutions and alternative treatment technologies to the maximum
extent practicable and satisfies the statutory preference for
remedies that employ treatment that reduces toxicity, mobility, or
volume as a principal element.
Da"te Patrick M. Tobin
Acting Regional Administrator
U.S. EPA Region IV
ill
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TABLE 07 CONTENTS
I. DECLARATION i
II. DECISION SUMMARY iv
Table of Contents iv
List of Figures and Tables vi
1.0 Site Name, Location, and Description '..... 1
2.0 Site History and Enforcement Activities 4
2.1 Peak Oil Site 4
2 .2 Bay Drums Site 6
3.0 Highlights of Community Participation l
4.0 Scope and Role of Operable Unit 8
5.0 Summary of Site Characteristics 9
5.1 Site Topography and Surface Features 9 "
5.2 Regional Geology 10.-
5.3 Regional Hydrogeology 11
5.4 Sampling Results 14-'
5.4.1 Groundwater 14
5.4.1.1 Southern Surficial Aquifer ... 14
5.4.1.2 Upper Floridan Aquifer 18
6.0 Baseline Risk Assessment Summary 22
6.1 Human Health Risks 22
6.1.1 Contaminants of Concern 23
6.1.2 Exposure.Assessment 24
6.1.3 Toxicity Assessment 24
6.1.4 Risk Characterization 29
6.2 Environmental Risks 33
7.0 Description of Remedial Alternatives 33
7.1 Alternative No. 1 - No Action 38
7.2 Alternative No. 2 - Containment 38
7.3 Alternative No. 3 - Active Restoration 40
7.3.1 Alternative No. 3A 40
7.3.2 Alternative No. 3B 41
7.3.3 Alternative No. 3C 42
7.3.4 Alternative No. 3D 44
7.4 Alternative No. 1 - No Action 45
7.5 Alternative No. 2 - Active Restoration 46
iv
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8.0 Comparative Analysis of Remedial Alternatives 47
Southern Surficial Aquifer
8.1 Overall Protection of Human Health and the
Environment 47
8.2 Compliance with Applicable or Relevant and
Appropriate Requirements 49
.8.3 Long-Term Effectiveness 49
8.4 Reduction of Toxicity, Mobility, or Volume
Through Treatment 50
8.5 Short-Term Effectiveness 50
8 . 6 Implement ability "....'.. 51
8.7 Cost 51
8.8 State Acceptance 52
8 . 9 Community Acceptance 52
Upper Floridan Aquifer
8.10 Overall Protection of Human Health and the
Environment 52
8.11 Compliance with Applicable or Relevant and
Appropriate Requirements 52
8.12 Long-Term Effectiveness 53.
8.13 Reduction of Toxicity, Mobility, or Volume
Through Treatment 53.-
8.14 Short-Term Effectiveness 53
8.15 Implementability 53-'
8.16 Cost 53
8.17 State Acceptance 53
8.18 Community Acceptance 54
9 . 0 Selected Remedy 54
9.1 Groundwater Remediation 54
9.1.1 The Major Components of the Groundwater
Remedy 55
9.1.2 Extraction, Treatment and Discharge.... 55
9.1.3 Performance Standards 56
9.1.4 Compliance Testing 58
10.0 Statutory Determinations 61
10.1 Protective of Human Health and the
Environment 61
10.2 Compliance with Applicable or Relevant and
Appropriate Requirements 61
10.3 Cost Effectiveness 63
10.4 Utilization of-Permanent Solutions to the
Maximum Extent Practicable 63
10.5 Preference for Treatment as a Principal
Element 63
11.0 Documentation of Significant Changes 64
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LIST OF FIGURES AND TABLES
Figures
Figure 1.1 Site Location Plan 2
Figure 1.2 Study Area Plan 3
Figure 2 .1 Site Plan 5
Figure 5.1 Typical Geologic Profile 12
Figure 5.2 Surficial Aquifer Well Location Plan 17
Figure 5.3 Upper Floridan Aquifer Well Location Plan 19
Tables
Table 5-1 Surficial Aquifer Sampling Results 15
Table 5-2 Upper Floridan Aquifer Sampling Results 21
Table 6-1 Potential Contaminants of Concern - Surficial
Aquifer 25 :
Table 6-2 Potential Contaminants of Concern - Upper
Floridan Aquifer 26
Table 6-3 Summary of Exposure Pathways for Groundwater 27
Table 6-4 Assumptions Used to Estimate Exposure Via
Ingestion of Groundwater 28
Table 6-5 Summary of Chronic RfDs and Slope Factors
(Oral) 30
Table 6-6 Summary of Chronic RfDs and Slope Factors
(Inhalation) 31
Table 6-7 Cancer Risk by Individual Pathway 34
Table 6-8 Hazard Risk by Individual Pathway 36
Table 8-1 Glossary of Evaluation Criteria 48
vi
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RECORD OF DECISION
Summary of Remedial Alternative Selection
Operable Unit Two - Groundwater Remediation
Pealc Oil/Bay Drums Superfund Site
Brandon/ Hillsborougb County/ Florida
1.0 Site Name/ Location, and Description
The Peak Oil/Bay Drums Site ("the Site") is located in north
central Hillsborough County, Florida within the southeast quarter
of Section 7, Township 29 South, Range 20 East (see Figure 1.1).
The site is located on State Road 574 (SR 574), approximately
0.25 miles west of Faulkenburg Road.
As shown on Figure 1.2, the Peak Oil facility is approximately
four acres in area and the Bay Drums facility is approximately
14.8 acres. The site is flanked on the east by the Reeves
Southeastern Wire Facility. Just south of the site are Peoples
Gas Company's natural gas distribution center and a soil and
construction debris pile referred to as the Shingle Pile, which _.
was moved by EPA to its present location from the Bay Drums Site "
during an EPA removal action in 1989. The Consolidated Bag
Company is located southwest of'the Shingle Pile.
An abandoned CSX Railroad spur runs south between the Peak Oil
and Bay Drums facilities. This spur once serviced the Tampa Bay
Sunshine Skyway Bridge painting site. Owned by Hillsborough
County, the area south of the Bay Drums Facility is undeveloped
and includes a portion of the Central Wetland. South of the
Central Wetland is an area which was historically used as a
sprayfield for the Hillsborough County Wastewater Treatment
Plant.
The Peak Oil Site currently has two warehouse-type buildings, a
concrete block office building, a small storage shed, a small
lagoon from which waste oil sludges were excavated during a
previous EPA removal action, a 6,000 cubic-yard ash pile lined
and covered with plastic liners (also from the previous EPA
removal action), and a 400 cubic-yard soil pile. A concrete pad,
90 feet by 110 feet, is also located in the southeast corner of
the site.
The Bay Drums Site currently contains three small ponds. The Bay
Drums pond comprises the southern tip of the original on-site
wetland and is now considered to be a portion of the Central
Wetland. The one-acre eastern wetland was backfilled with
material excavated from the site. There is one building located
on the site.
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STUDY AREA
VICINITY MAP
NOT TO SCALE
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SfTE LOCATION PLAN
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PEAK OIL SUPERFUND SfTE
TAMPA. FLORIDA
FXGORI 1.1
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The closest residential areas to the site are single-family
houses and mobile homes, located approximately 0.3 miles east of
the Site across Faulkenburg Road. Other residential areas
include single-family homes, approximately 0.75 miles north of
the site across SR 574 on Martin Luther King Avenue; single-
family houses in an area approximately 1.2 miles west of the site
near the intersection of U.S. Highway 301 and SR 574; and single-
family residences and mobile homes in an area approximately 1.8
miles northeast of the property on Six Mile Road.
Three wetlands are adjacent to the site, to the southwest,
southeast, and northwest. Stormwater runoff drains primarily to
the west, but a small part of the site drains off to the
southeast. The southwest corner of the site is subject to
inundation during wet seasons due to the high groundwater table,
but it is not within any drainage flood plain.
2.0 Site History and Enforcement Activities
2.1 The Peak Oil Site
The Peak Oil Facility was constructed and began operation as a
waste oil re-refinery in August 1954, under the ownership of
Mr. John Shroter. Ownership of the company was transferred in
1975 to Mr. Robert Morris. Mr. Morris and his sons continued the
operation of the business as a waste oil re-refinery. After
1979, operations reportedly were limited to the resale of used
oils as fuel and flotation oil and repackaging of virgin
material.
Facility operations involved the use of a waste re-refining
process to purify waste oils and lubrication fluids. Waste oils
accepted at the facility for re-refining consisted primarily of
used auto and truck crankcase oil, with some hydraulic oil,
transformer oil and other waste oils.
An acid/clay purification and filtration process was used to
re-refine the oil. This process generated a low pH sludge and
oil-saturated clay, which were stored over the life of the
facility in three separate impoundment areas (Lagoons No. 1, No.
2 and No. 3). Two impoundments, Lagoons Nos. 2 and 3, were
connected by an oil/water separator. The locations of the
lagoons arc shown on Figure 2.1.
In 1979 or 1980, the company discontinued the re-refining process
and shifted to filtering and blending the waste oil for resale as
burner fuel or flotation oil. Several company employees have
reported that spills and leaks continued to occur from on-site
storage tanks, tanker trucks, oil/water separators, and other
on-site equipment after the company shifted its operations from
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re-refining to filtering and blending. The former employees also
reported that some wastes continued to be stored in the on-site
lagoons after the shift to filtering and blending operations.
Lagoon No. 1 and Lagoon No. 3 were backfilled. However, the
exact dates of backfilling are unknown. Lagoon No. 2 is the only
impoundment on the site that was not backfilled. This lagoon
originally contained up to 12 feet of sludge. Overflow from
Lagoon No. 2 was apparently directed to the oil/water separator
to remove free oil, and the aqueous phase was discharged into
Lagoon No. 3, to the east. EPA and the FDEP conducted
inspections at the Peak Oil and Bay Drums Sites and reported that
various chemical constituents were present in site soils,
including heavy metals, petroleum hydrocarbons, trace
concentrations of polychlorinated biphenyls (PCBs), and solvent-
type chemical compounds.
In 1984, the Peak Oil and Bay Drums Sites were jointly evaluated
according to the Hazard Ranking System and proposed for listing
on the National Priority List (NPL) with a score of 58.15. On
June 10, 1986, the Peak Oil Site, combined with the adjacent Bay
Drums Site, was placed on the NPL. EPA initiated a removal
action utilizing a mobile incinerator to treat sludge found in
Lagoon No. 2 in 1986. In 1989, members of the Peak Oil
Generators Group entered into a Consent Order with the EPA to
conduct a remedial investigation/feasibility study (RI/FS) at the
Peak Oil Site.
For the Peak Oil/Bay Drums groundwater operable unit, some 3200
potentially responsible parties (PRPs) have been identified. All
PRPs will be issued notice letters inviting them to participate
in the negotiations for the Remedial Design/Remedial Action.
2.2 The Bay Drums Site
Prior to development of the Bay Drums property in 1962, the
property was an open field with some small trees. A one-acre
wetland on the east side of the site drained to the Central
Wetland, about 300 feet to the southwest.
The Bay Drums Facility was historically operated as a drum
reconditioning facility, however, it is no longer operational.
During operation, drum reconditioning activities occurred within
the building on the eastern portion of the site. Although nearly
the entire property has been used for drum storage, only
approximately two acres in the northeast corner of the site were
considered an active drum reclaiming area.
A berm was constructed between 1962 and 1965 that crossed the
southern one-third of the one-acre wetland, which at that time
existed on the eastern portion of the Bay Drums Site. This
effectively dried out the southern portion of this wetland. The
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northern portion of this wetland was reported to be hydraulically
connected to the Peak Oil Site by means of a culvert beneath the
CSX Railroad spur, allowing water to drain from the Peak Oil Site
to the northern portion of the wetland. The northeast and south
portions of the Bay Drums Site were purchased by Mr. Bennie
Genuardi, the owner of the Bay Drums facility, from the Shroters
and the Atlantic Coastline Railroad in 1967 and 1968,
respectively.
The volume of drums reconditioned at the site increased from 1974
to 1978 under the ownership of Tampa Steel Drums. Drums were
located along the western edge of the wetland in 1975. "in a 1977
aerial photograph, the wetland had been backfilled. Presumably,
soil from a new pond on the southeast corner of the Bay Drums
Site had been used to backfill the wetland. Drainage from the
Peak Oil Site was reportedly diverted by ditch to the Central
Wetland. In 1978, the western portion of the previously filled
wetland was developed into a washwater holding pond which is
known to have received waste from drum reconditioning activities.
Drum reconditioning activities ceased in 1982.
In 1984, the Peak Oil and Bay. Drums Sites were jointly evaluated
according to the Hazard Ranking System and proposed for the NPL
with a score of 58.15.
For approximately two and one-half years beginning in 1984, the '
Bay Drums Site was operated as Resource Recovery Association,
Inc. During this time waste roofing shingles were deposited on
most of the site to depths ranging from three to more that
nineteen feet. In 1989, the EPA removed approximately 70,000
cubic yards of shingles in order to effectively evaluate the
extent of soil contamination at-the site. The pile currently
lies on Hillsborough County. EPA conducted another removal
action at the site in 1990 and removed contaminated soils, drums
of hazardous waste, and bags of pesticides from the site.
3.0 Highlights of Community Participation
In accordance with Sections 113 and 117 of CERCLA, EPA has
conducted community relations activities at the Peak Oil Site to
ensure that the public remains informed concerning activities at
the site, EPA issued press releases to keep the public informed.
There was some local press coverage at EPA's activities, and EPA
held meetings with local (county) and state officials to advise
them of the progress at the site.
A community relations plan (CRP) was developed in 1988 and
revised in 1989 to establish EPA's plan for community
participation during remedial activities. Following completion
of the RI/FS, a Proposed Plan fact sheet was mailed to local
residents and public officials on February 18, 1993. The fact
sheet detailed EPA's preferred alternative for addressing the
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groundwater contamination (Operable Unit Two) at the Peak Oil/Bay
Drums Site. Additionally, the Administrative Record for the
site, which contains site related documents including the RI and
FS reports and the Proposed Plan, was made available for public
review at the information repository in the Brandon Public
Library. A notice of the availability of the Administrative
Record for the Peak Oil/Bay Drums Site was published in the Tampa
Tribune on February 18, 1993 and again on February 23, 1993.
A 60-day public comment period was held from February 20, 1993 to
April 21, 1993 to solicit public input on EPA's preferred
alternative for Operable Unit Two. EPA had a public meeting on
February 24, 1993 at the Brandon Regional Library to discuss the
remedial alternatives under consideration and to answer any
questions concerning the proposed plan for the Site. EPA's
response to each of the comments received at the public meeting
or during the public comment period is presented in the
Responsiveness Summary which is provided as Appendix A of this
ROD.
This decision document presents the selected remedial action for
Operable Unit Two of the Peak Oil/Bay Drums Site in Brandon,
Florida, chosen in accordance with CERCLA, as amended by SARA,
and to the extend practicable, the NCP. This decision is based .-
on the Administrative Record for the site.
4.0 Scope and Role of Operable Unit
As with many Superfund sites, the problems at the Peak Oil/Bay
Drums Site are complex. As a result, EPA has divided the remedy
for the site into four operable units (OUs). These are:
o OU One: Contamination in the soils and sediments at
the Peak Oil Site;
o OU Two: Contamination in the groundwater and surface
water at the Peak Oil and Bay Drums Sites;
o OU Three: Contamination in the soils and sediments at
the Bay Drums Site;
o OU Four: Contamination in the wetlands at the Peak
Oil, Bay Drums, and Reeves Southeastern
Sites.
The remedial actions for OUs One, Three and Four will be
addressed in separate RODs.
OU Two is addressed in this ROD. Thus, the purpose of the
selected remedy is to remediate contaminated groundwater and
surface water. Potential ingestion of groundwater contaminated
above Maximum Contaminant Levels (MCLs) poses the principle
8
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threat to human health at the Peak Oil/Bay Drums Site. The
purpose of the remedy selected in this ROD is to remove
contamination above MCLs in both aquifers and Secondary Maximum
Contaminant Levels (SMCLs) in the Upper Floridan aquifer.
5.0 Summary of Site Characteristics
The climate in the Tampa area is characterized by mild winters
and relatively long, humid, and warm summers. Spring and fall
tend to be dry, with the majority of the rainfall occurring in
the summer.
5.1 Site Topography and Surface Features
Topographically, ground surface elevations at the site and
surrounding areas range in elevation from about 25 feet above
mean sea level (MSL) at the northwestern boundary to 45 feet
above MSL towards the eastern boundary. Due to the study area's
elevation above MSL, tidal surges will not impact the area. The
area south of SR 574 demonstrates only minor changes in
elevation. The southern portion of the Bay Drums and Peak Oil
Facilities slopes gradually toward the south and southwest toward.
small wetland areas (referred to as the South Wetland and the
Central Wetland) . The ground surface elevation at the Peak Oil .-
Facility varies slightly from about 39 to 42 feet above MSL.
Two wetland areas exist within and adjacent to the site. The
Central Wetland, which is south of the Bay Drums property and
within the study area, has no surficial outlet, except during
periods of heavy rainfall when the water from the wetland flows
overland to the ditch north of the Bay Drums property. This
wetland, which was formerly distinct from the Bay Drums Facility,
is presently connected hydrologically aboveground with the Bay
Drums pond, which is the southern tip of the original on-site Bay
Drums wetland.
The South Wetland is located south of the study area between
Reeves Road and Columbus Avenue. It is the larger of the two
wetlands and is also the further from the site than the Central
Wetland.
The Peak Oil Site currently contains one lagoon and several ponds
or ponded areas. As shown on Figure 2.1, Lagoon No. 2 is located
in the southwest portion of the Peak Oil Facility. There are
three ponded areas in the northwest sector of the property,
adjacent to the two large warehouse buildings. The two ponded
areas along the northern boundary of the property were formerly
one continuous depression that had been divided at its midpoint
by an earthen berm. This northern depression retains standing
water only during the rainy seasons or after events of heavy
rainfall. The pond in the northwest corner of the property is
surrounded by thick vegetation. Generally, surface water exists
-------
in .this pond on a continuous basis with the water depth primarily
dependent upon the groundwater level.
Currently, an ash pile of approximately 6,000 cubic yards is
located in the northeast portion of the Peak Oil Facility. This
ash was generated during EPA's 1985 to 1987 on-site incineration
of waste sludges and is sitting on and covered with a plastic
liner. EPA also constructed a concrete pad on the southeastern
portion of the site as part of the incineration removal action.
Although the southern part was later removed, approximately 7,000
square feet of the original pad still remain. Approximately 400
cubic yards of soil which were stockpiled on the Peak Oil Site
during EPA's 1990 and 1991 Bay Drums and Peak Oil removal actions
currently remain south of the large warehouse building.
Prior to development in 1962, the Bay Drums Site consisted of an
open field sparsely populated with small trees with an
approximately one-acre wetland on the eastern portion of the
site. This wetland drained into the Central Wetland
(approximately five acres) 300 feet to the southwest of the site.
Surface drainage on the northern portion of the site flows north
to a ditch along the southern side of the CSX Railroad and then
through culverts under the railroad and SR 574 to the North
Wetland, located next to the Reeves Southeastern Galvanizing
Facility. The southern portion of the site drains to the Central
Wetland area south of the site. The Central Wetland has no
surficial outlet.
The one-acre eastern wetland has been backfilled, possibly with
material excavated from the southeast corner of the site. After
the backfilling, the eastern wetland is now termed the backfilled
wetland and the Bay Drums pond. The site also has a waste
holding area just south of the Bay Drums Facility (Building).
This holding area is known to have received wastes from the drum
reconditioning activities, but its date of construction is
unknown.
Land use in the area is generally industrial or undeveloped, with
the nearest single family residential area being 0.3 miles east
of the site. It is anticipated that the primarily industrial
character of the area surrounding the site will be maintained in
the future.
5.2 Regional Otology
The geology of the Tampa area consists of a series of sedimentary
sequences of rock and unconsolidated sediments overlying a
basement of crystalline igneous or metamorphic rock. The
basement rock is of Paleozoic age, and the sedimentary rocks
range in age from Mesozoic era through the Pleistocene epoch of
the Cenozoic era.
10
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The upper rock and sediment sequences include the Tampa limestone
member of the Hawthorn Group (referred to as the Upper Floridan
Aquifer), the Arcadia formation and Peace River formation of the
Hawthorn Group (referred to as the low-permeability unit or low-
permeability layer) and undifferentiated Pliocene, Pleistocene
and Holocene deposits (referred to as the surficial aquifer).
The limestone layer is approximately 80 feet to 400 feet thick,
varying throughout the area, the Hawthorn clay layer is 15 feet
to 40 feet, and finally the surficial sand ranges from 9 feet up
to 37 feet in some areas. (See Figure 5.1)
Sedimentary rocks and unconsolidated deposits in the Tampa area
consist of limestones, sand, clay and silt. The variability of
rock and sediment types suggests environments of deposition
ranging from open ocean to shoreline to lagoons and tidal
marshes. The rock sequence consists of sand, fine-grained
carbonate rocks and fine-grained clay or shale.
Rocks of the Miocene age underlie most of the Tampa area, and
these strata are mostly clastic, with the exception of (1) sandy
limestone that comprises the Tampa member and its equivalents and
(2) dolomite beds that commonly make up the lower part of the
Arcadia formation.
The Suwannee Limestone formation and the overlying Tampa
Limestone member comprise the upper portion of the Upper Floridan'
Aquifer. The Suwannee Limestone formation consists of white,
yellow and light-brown, soft to hard, dense, fine-grained
limestone with chert lenses to 25 feet thick.
The Hawthorn Group consists of highly variable sequences, mostly
of clay, silt and sand beds, all of which contain scarce to
abundant phosphate. The clays are characterized by swelling when
hydrated and have the ability to absorb and retain certain ions
in an exchangeable state.
The Hawthorn generally consists of a basal calcareous unit and a
middle clastic unit known as the Arcadia formation, and an upper
unit that is a highly variable mixture of clastic and carbonate
rocks, known as the Peace River Formation. The middle and upper
parts of the Hawthorn everywhere contain more phosphate than the
lower calcareous unit. Because of its heterogeneity and the
predominantly fine-textured nature of both the clastic and the
carbonate beds within the Hawthorn, the entire group constitutes
a low-permeability rock unit except for the Tampa limestone
member.
5.3 Regional Bydrogeology
The groundwater system beneath the study area consists of two
major water-bearing units: a class II surficial aquifer (the
term surficial aquifer refers to permeable material that is
11
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GROUND SURFACE
H
to
FORMATION
UNOIFFERENTIATED
SAND DEPOSITS
HAWTHORN
TAMPA
LIMESTONE
OVERLYING
SUWANNEE
LIMESTONE
GENERAL LITHOLQGY
PRCOOUINANIIY flNC SAND;
!NltROOOCO CU». M*Rl.
SUCH. UMtSlONC. PHOSPHORitl
GRECN. BlUC. AND CRAY CUYCY
SAND AND CUT. UMCSIONC NtAR
QOI10M or fORUAIiON IS wml( 10
CRAY. son. SANDY. AND POROUS.
fORMAIION CCNCRAllY COMSIS1S
Of A BASAl CAICARCOUS UMII.
A UlCIDlC CUSHC UNII. AND
AN UI'PCR UNII Of CUStlC
AND CAROONAtt ROCK AND SOU
UlDDlt ANO UPPtn PARIS
CUNIAIN UONC PHOSPMAlf.
IMAN LOWER CAICAHCOUS UNH
(NOIt UPPCR PAHt Of lAUPA
fORMAIION IS RClAllVCLY MICM
IN CUY CONUNI MAKING COHIAf.l
BCTVtCN IAUPA ANO HAWlHORH
oirncoii 10 ocitRuiNi )
WHItC. CRIAU. AND CRAY HARD
10 son. SANDY UMCSIONC.
SANOY. pHOSPMAttc. rossinrtnous
WIIM otrni ICNSCS: SAND ANO
CUY IN LOWCR PAR I IN SOut
StCliONS. MANY UOIDS Of
PtltCYPODS ANO CASIROPOOS
Wllllt YCllOW ANO UCH1 ORO*II
Son 10 HARD D[NSt. fiNC-
CRAINCO IIUCS10NC Wllll CHI (II
UNSfS to ?i ftd
rossinrcROus
SAND
V////A CLAY
-'#- '\ CLAYEY
irm S1LT
li ! i * i H LIMESTONE
* * I PHOSPHATIC NODULES
7 I Tj
«... * I CHERT
~ *~1
a I CALCAREOUS UNIT
TYPICAL GEOLOGIC PROFILE
SITE SOURCE CHARACTERIZATION
PEAK OIL SUPERFUND SITE
TAMPA. FLORIDA
FIOURR 5.1
-------
exposed at land surface and that contains water under unconfined
conditions) and the class I Floridan Aquifer system. A low-
permeability unit comprised of a low-permeability sequence of
rocks separates the Floridan from the upper surficial aquifer.
The Floridan Aquifer system consists of a thick sequence of
carbonate rocks of the Tertiary age. The unit is comprised of
white to light-gray, sandy, hard to soft, locally clayey,
fossiliferous (pelecypod and gastropod casts and molds) limestone
that contains phosphate and chert in places.
The phosphate content of the Tampa limestone is low, however, in
comparison with that of the overlying Arcadia and Peace River
Formation. Much of the Tampa member contains soft lime muds and
solution cavities. Therefore, the Tampa limestone is highly
porous in some zones, and its porous nature permits large volumes
of water to flow through it. The upper part of the Tampa
limestone is relatively high in clay content, making the contact
between it and the clayey Arcadia formation difficult to
determine.
Rainfall infiltrates the permeable surficial materials and, after
percolating downward to the water table, generally moves
laterally to points where it is discharged into surface streams ..
and wetlands. Water levels within the surficial aquifer
fluctuate seasonally and change rapidly in response to rainfall
and other natural stresses such as evapotranspiration or the
stages of streams. The groundwater flow patterns also change due
to the increased rainfall during the summer months which raises
the surface water elevation in the wetlands and lagoons, changing
them into recharge basins for the surficial aquifer.
The thickness and lithologic character of the low-permeability
layer that separates the surficial aquifer from the Upper
Floridan Aquifer system determine the degree of hydraulic
interconnection between the two. Where the low-permeability unit
is thick or where it contains a.high concentration of clay, there
is essentially no interconnection between the surficial and
Floridan aquifers. In these thick or clay-rich areas, water in
the surficial aquifer moves laterally as opposed to vertically
and does not breach the low-permeability unit. The low-
permeability unit is breached in some locations, such as uncased
boreholes, that serve to reduce the hydraulic separation between
the aquifers.
The regional groundwater flow pattern within the Upper Floridan
Aquifer is based upon the USGS potentiometric surface map. The
contour map and review of the water level plots indicate the
regional groundwater flow is in a southwesterly direction in this
area. The Tampa Bypass Canal divides the regions and forces the
flow direction to shift northwesterly near the site. Reportedly,
the canal excavation cut into the low-permeability layer and
13
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breached the Upper Floridan Aquifer in several places. In the
vicinity of the site, the general groundwater flow direction is
northwesterly.
Approximately 70 percent of the.annual precipitation in the Tampa
area is lost through evapotranspiration and about nine inches of
the 47 inches of annual precipitation is available for
groundwater recharge.
The surficial aquifer is composed of undifferentiated Pliocene
and Pleistocene age deposits. The groundwater is suitable for
domestic and small-quantity municipal supplies, although" in some
areas there is a high iron content and near the bays there is a
high chloride content. The surficial aquifer underlies both the
Peak Oil/Bay Drums Site and the Reeves Southeastern Site. EPA
has divided the aquifer into two sections, the northern section
is located under the Reeves Southeastern Site and the southern
section is located under the Peak Oil/Bay Drums Site; and thus is
discussed in this ROD. The remediation of one section of the
aquifer will have little or no effect on the remediation of the
other section.
5.4 Sampling Results
The RI included sampling of groundwater, surface water and
sediment. Samples from each of these media were analyzed for
volatile organic compounds (VOCs), semi-volatile organic
compounds (SVOCs), organochlorine pesticides (OCPs) and PCBs, and
various inorganic parameters. The analytical results for
groundwater samples are discussed in the following section.
5.4.1 Groundwater
The RI included sampling of groundwater from monitoring wells
completed in the surficial aquifer and from monitoring and
production wells completed in the Upper Floridan Aquifer. The
analytical results for groundwater samples are discussed below in
Sections 5.4.1.1 and 5.4.1.2.
5.4.1.1 Southern Surficial Aquifer
The Baseline Risk Assessment includes the sampling results from
the surficial groundwater monitoring wells. Table 5-1 shows the
average and maximum concentrations in the surficial aquifer for
each chemical of concern.
Volatile Organic Compounds
Volatile organics are present in the surficial aquifer in the
area of the Bay Drums Site, and-to a lesser extent at the Peak
Oil Site. However, despite the relatively large areal
distribution of VOCs, the area of concentrations greater than
14
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Table 5-1
Surficial Aquifer Sampling Results
Contaminant of Concern
Aluminum
Antimony
Arsenic
Benzene
Bis (2-chloroethyl) ether
Bis (2-ethylhexyl)phthalate
Chromium
1, 1-Dichloroethane
I, 1-Dichloroethylene
Total -1, 2-Dichloroethylene
Ethylbenzene
Iron
Lead
Manganese
Methylene Chloride
Naphthalene
Sodium
Tetrachloroethylene
Toluene
Total Xylenes
1,1, 1-Trichloroethane
1,1,2 -Trichloroethane
1, 1-Trichloroethylene
Vanadium
Vinyl Chloride
Zinc
Highest
Concentration
58.7
0.0276
0.0950
0.150
0.0410
0.0220
0.780
5.40
43.0
2.50
4.00
506
0.180
4.30
6.80
2.10
8,490
0.014
170
12.0
75.0
0.160
0.180
0.120
0.110
337
Average
Concentration
6.27
0.0223
0.0086
0.0226
0.0098
0.0076
0.0404
0.280
1.37
0.141
0.178
18.1
0.0134
0.298
0.285
.0178
311
0.0029
6.04
0.598
2.35
0.0071
0.0118
0.0356
0.0098
17.5
15
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federal and state of Florida MCLs is limited. Most of the
concentrations greater than MCLs are found in wells at the Bay
Drums Site, as can be seen in the following list of contaminants
present in surficial aquifer wells. The list illustrates wells
in which promulgated or proposed federal MCLs and Florida MCLs
are exceeded. The locations of-the wells are shown on Figure
5.2. It should be noted that all wells beginning with "B" are
located on the Bay Drums Site and those beginning with "P" are
located on the Peak Oil Site.
Chemical Well
Benzene B-2, B-3, B-5, B-6, B-7, B-10,
B-ll, P-7, P-8, P-9
1,2-DCA B-5,B-10
1,1-DCE B-5, B-7, B-9, B-10, P-3
1,2-Dichloropropane B-10
Ethylbenzene B-l, B-7
Methylene Chloride B-l, B-2, B-5, B-7, B-9, P-3, P-7, .
P-9
1,1,1-TCA B-7
1,1,2-TCA B^7
TCE B-7, B-9, P-3, P-7
Tetrachloroethylene B-l, B-9
Toluene B-l, B-7, P-3
Vinyl Chloride B-l, B-2, B-3, B-5, B-9, B-10, P-3,
P-8, P-9
Total Xylenes B-l
The area most heavily impacted with VOCs is on the south side of
the Bay Drums site. In this area, concentrations of benzene,
1,2-dichloroethane (1,2-DCA), 1,1-dichloroethane (1,1-DCE),
1,1,1-trichloroethane (1,1,1-TCA), trichloroethane (TCE),
methylene chloride, ethylbenzene, toluene, 1,1,2-trichloroethane
(1,1,2-TCA), and vinyl chloride are present at concentrations
above MCLs. Near the railroad tracks and drainage ditch, north
of the Bay Drums site, benzene, 1,2-DCA, vinyl chloride and 1,1-
DCE are also found at concentrations above MCLs.
16
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tJ
o
oo
70 70
on
r : - : - UNIUPHOVCO ROAOWAT
OKAINACC OUCH
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(^) SIANOINC WAIfH
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e SURfClAL AOuilCf) PlCiOutlCR
NOTES:
i coonoiNAic cue is RtdRfNCto 10 ini nomo*
SIAIC PLANE COOROIHAIC STSIEM
SURFICWO. AQUIFER
WELL LOCATION PLAN
HAT DRUMS. PEAK OIL. AND REEVES
SUPERFUNO SUES
TAMPA. FLORIDA
FIGURE 5.2
IUIttJM.Uk
-------
Concentrations of VOCs above MCLs are also present throughout
much of the central Bay Drums area and the northern and southern
boundary areas of the Peak Oil Site.
Semi-Volatile Organic Compounds
Concentrations of SVOCs in the surficial aquifer are generally
much lower than concentrations of VOCs. SVOCs were detected in
wells at both the Bay Drums and Peak Oil Sites, notably Wells P-3
and B-l.
Organochlorine Pesticides and Polvchlorinated Biphenvls
Six OCPs were detected in surficial aquifer monitoring wells.
Five were detected in Bay Drums wells, and the highest detected
concentration was 0.0019 ppm of gamma chlordane in Well B-l.
No PCBs were detected in surficial aquifer groundwater samples.
Inorganic Compounds
Inorganic compounds were detected in surficial wells throughout
the Site. Of the 23 constituents detected, eight are found at
concentrations above MCLs. These compounds are antimony,
arsenic, beryllium, cadmium, chromium, lead, nickel and sodium.
Well P-3 which is located at the south edge of the Peak Oil Site '
contains elevated concentrations of several metals.
Concentrations of inorganic compounds exceeding MCLs are also
found downgradient from the site.
5.4.1.2 Upper Floridan Aquifer
The Area-Wide RI included sampling eight monitoring wells and six
production wells in the Upper Floridan Aquifer (See Figure 5.3
for well locations). The samples were analyzed for VOCs, SVOCs,
OCPs/PCBs and various inorganic parameters.
The groundwater quality and water level data obtained during the
RI suggests that Wells F-2 (Peak Oil Production Well) and F-3
(Bay Drums Production Well) acted as conduits for the vertical
migration of contaminated groundwater from the surficial aquifer
to the Upper Floridan Aquifer. Chemical concentrations detected
in the two production wells are similar to concentrations found
in the surficial aquifer and much higher than concentrations
detected in other adjacent Floridan Aquifer wells. During a
borehole video investigation, groundwater from the surficial
aquifer was observed flowing into the casing of Well F-3.
PCBs were not detected in the Upper Floridan Aquifer wells and
only one pesticide was detected in the surficial aquifer.
Detections of VOCs, SVOCs and inorganic constituents are
presented in the following sections.
18
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SIAIC PLANE COORDINATE SYSICU
UPPER FLORIOAN AQUIFER
WELL LOCATION PLAN
DAY DRUMS. PEAK OIL. AND REEVE
SUPCRFUND SITES
TAMPA. FLORIDA
PIGURX 5.3
G
-------
Impacts were primarily found in two wells, Well F-2 and Well F-3.
Of the 21 volatiles detected in the aquifer, two of the maximum
volatiles concentrations were detected in wells other than
F-2 and F-3. Of the 56 constituents detected in the aquifer,
concentrations of chemicals exceeding MCLs occurred 17 times in
wells other than F-2 and F-3.
Table 5-2 illustrates the highest concentration detected and the
average concentration of each chemical of concern in the sampling
results from the Upper Floridan Aquifer.
Volatile Organic Compounds
Chemical concentrations detected in samples from Wells F-2
and F-3 are generally higher than other adjacent Floridan Aquifer
wells. Thirteen VOCs were detected in Well F-2, of which six
were reported at concentrations above the MCL. Fifteen VOCs were
detected in Well F-3, of which five were reported at
concentrations above the MCL. Many of the same constituents
detected in wells F-2 and F-3 were also detected in the surficial
aquifer near the wells. Other monitoring wells where VOCs were
detected above federal and/or state MCLs include Wells F-8, F-9, ..
F-ll and F-12. In each of these wells, one chemical was detected"
at concentrations higher than MCLs. Trichloroethylene (TCE) was -
detected in Wells F-8 (0.008 ppm) and F-9 (0.004 ppm) above the
state MCL of 0.003 ppm. Well F-12 also contained TCE (0.011 ppm)-'
and methylene chloride at concentrations above the MCLs. The
only chemical detected in Well F-ll above the MCL was 1,1
dichloroethylene, which was detected at 0.013 ppm.
Semi-Volatile Organic Compounds
Sixteen SVOCs were also observed at low concentrations in Wells
F-2 and/or F-3. Seven VOCs including ethylbenzene and toluene
were above MCLs in Well F-3. Well F-12 had two VOCs that were
above MCLs; methylene chloride and TCE.
Inorganic Compounds
Fourteen inorganic constituents were present at concentrations
below MCLs in the samples collected from Wells F-2 and F-3. Nine
of these inorganic compounds were also present in the Upper
Floridan Aquifer background sample from Well F-l, located 1.5
miles from the site.
Arsenic, beryllium, and lead were detected slightly above MCLs in
scattered locations in the Upper Floridan aquifer. However, in
most cases, inorganics in wells other than Well F-2 or F-3 were
below MCLs.
20
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Table 5-2
Upper Floridan Aquifer Sampling Results
Chemical of Concern
Aluminum
Arsenic
Benzene
1, 1-Dichloroethane
1, 1-Dichloroethylene
total -1 , 2 -Dichloroethy lene
Ethylbenzene
Iron
Lead
Magnesium
Methylene Chloride
Naphthalene
Sodium
Tetrachloroethylene
Toluene
1,1, 1-Trichloroethane
1,1,2 -Trichloroethane
Trichloroethylene
Vanadium
Total Xylenes
Zinc
Highest
Concentration
0.600
0.130
0.0130
1.20
1.50
0.130
0.390
6.90
0.0059
10.1
0.440
0.140
52.0
0.0005
10.0
0.160
0.0220
0.0210
0.0339
1.60
5.99
Average
Concentration
0.185
0.0186
0.0022
0.112
0.128
0.016
0.034
1.69
0.0018
3.765
0.041
0.025
19.82
0.0002
0.837
0.0135
0.0020
0.0045
0.0259
0.135
0.637
21
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6.0 Baseline Riflk Aaseeament Summary
A risk assessment provides a systematic means for organizing,
analyzing, and presenting information on the nature and magnitude
of risks posed by chemical exposures. Nevertheless,
uncertainties and limitations are present in all risk assessments
because of the quality of available data and the need to make
assumptions and develop inferences based on incomplete
information about existing conditions and future circumstances.
These uncertainties and limitations should be recognized and
considered when discussing quantitative risk estimates.
In general, the uncertainties and limitations in the risk
assessment can be classified in the following categories:
o environmental sampling and laboratory measurement;
o mathematical fate and transport modeling;
o receptor exposure assessment; and
o toxicological assessment.
Some areas of uncertainty in the exposure assessment of the Peak .-
Oil/Bay Drums Site include:
o There is no reasonable likelihood that the sites will
be developed for residential uses in the future, as it
is currently zoned for industrial use only.
o It is unlikely that either aquifer will be used as a
source of drinking water in the future.
o Soil ingestion rates of 50 mg/day and 100 mg/day were
considered in this assessment.
6.1 Human Health Risks
A baseline risk assessment (RA) was conducted as part of the RI
to estimate the health or environmental problems that could
result if the Bay Drums/Peak Oil site was not remediated. A
baseline risk assessment represents an evaluation of the "No
Action" alternative in that it identifies the risk present if no
remedial action is taken. 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: contaminants of concern, exposure
assessment, toxicity assessment, and risk characterization.
22
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6.1.1 Contaminants of Concern
The groundwater RA was conducted as an area-wide study involving
the Peak/Bay and Reeves sites. The procedure conducted for
determining the groundwater exposure point concentrations (EPCs)
was averaging groundwater concentrations over the three site
area. The major concern was that by averaging over the entire
three-site area, the EPCs would be diluted which would have the
effect of decreasing the cumulative risk level and could allow
certain chemicals with unacceptable hotspot concentrations to
drop out of the risk assessment. A concentration-toxicity screen
was used to determine the site contaminants of potential concern
(COPC). This screening procedure eliminated chemicals from the
COPC list which were contributing less than 1% to the overall
site risk.
Since both the use of an areawide EPC and the results of the
concentration-toxicity screen could serve to eliminate chemicals
which should be included in the site remediation, it was decided
that the risk assessment staff would provide the PRPs with a list
of chemicals which had been eliminated as COPCs from the risk
assessment but which would be included as site contaminants
requiring remediation. A discussion of these chemicals was added
to the risk assessment and remediation goals were also calculated'
for them. For this reason, the Selected Remedy section
(Section 9.0) may contain additional chemicals not contained in '
the Baseline Risk Assessment Summary section (Section 6.0).
The use of an averaged area-wide EPC, as opposed to being
calculated based on the site plume, tends to lower the EPC.
Organics were either detected at low concentrations or generally
not at all on the Reeves site, thus the effect of using an
areawide average is to lower the EPCs for Peak Oil/Bay Drums.
However, this contribution does not affect the content of the
risk assessment since the risk associated with organic chemicals
greatly exceeds the upper end of the acceptable risk range.
Concerning the following inorganics; arsenic, chromium, lead and
nickel, although the EPC represents input from both sites, there
are wells on all three sites with concentrations exceeding MCLs
and which will require remediation based on individual
concentrations.
Generally, the contaminants that are of the most concern are the
volatile organic compounds and the semi-volatile organic
compounds. The chemicals which contribute most significantly to
the risks associated with groundwater ingestion include
1,1,-dichloroethane, vinyl chloride, arsenic, zinc and
naphthalene.
In the surficial aquifer, the VOCs with the highest
concentrations are benzene, 1,2-dichloroethane, 1,1-
dichloroethene, 1,1,1-trichloroethane, trichloroethane, and vinyl
23
-------
chloride. The inorganics with the highest concentrations are
antimony, arsenic, beryllium, cadmium, chromium, lead, nickel,
and sodium. Table 6-1 lists the Potential Contaminants of
Concern and their Exposure Points for the surficial aquifer.
In the Upper Floridan Aquifer, the two most contaminated areas of
groundwater are at the production wells of each site. The
chemicals of concern are arsenic, beryllium, lead, vinyl chloride
and methylene chloride. Table 6-2 lists the Potential
Contaminants of Concern and their Exposure Points for the
Floridan Aquifer.
6.1.2 Exposure Assessment
The future potential exposure pathways for the groundwater at the
Peak Oil/Bay Drums site are divided into two sections; future use
conditions for an onsite worker and future use conditions for an
onsite resident. These pathways are summarized in Table 6-3.
The most likely future use of the sites is industrial
development, which is consistent with the current zoning and the
land use. The future potential exposure pathways are direct
ingestion by onsite workers of the groundwater from both the
surficial and Upper Floridan aquifers which could be used as a
source of drinking water.
The future exposure pathways for onsite residents include direct
ingestion of the groundwater from both the surficial aquifer and
the Upper Floridan Aquifer when they are used for domestic water
supplies, and also dermal absorption of contaminants in
shower/bath water. Exposure to.chemicals volatilizing from water
during showering is considered a potentially significant route of
exposure.
The assumptions used to estimate exposure via ingestion of
groundwater are listed in Table 6-4.
6.1.3 Toxicitv Assessment
Slope factors (SFs) have been developed by EPA's Carcinogenic
Assessment Group for estimating excess lifetime cancer risks
associated with exposure to the potentially carcinogenic
contaminant(s) of concern. 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 risk associated with
exposure at that intake level. The term 'upper bound" reflects
the conservative estimate of the risks calculated from the SF.
Use of this approach makes underestimation of the actual cancer
risk highly unlikely. Slope factors are derived from the results
"24
-------
Table 6-1
Potential Contaminanta of Concern
Surficial Aquifer
Chemical
Aluminum
Ant imony
Arsenic
Bis(2-
chloroethyl) ether
Bis(2-
ethylhexyl ) phthalate
Cadmium
Chromium
1, 1-Dichloroethane
1, 1-Dichloroethylene
total-1,2-
Dichloroethylene
Ethylbenzene
gamma Chlordane
Iron
Exposure
Point
(ppm)
8.99
0.0291
0.012
0.0126
0.01
0.0050
0.0676
0.599
3.64
0.298
0.380
0.0001
36.6
Chemical
Lead
Manganese
Mercury
Methylene Chloride
Naphthalene
Sodium
Toluene
Total Xylenes
1,1,1-
Trichloroethane
1,1,2-
Trichloroethane
Vanadium
Vinyl Chloride
Zinc
Exposure
Point
(ppm)
.0134*
0.522
0.00017
0.648
0.342
605
14.5
1.25
0.0156
0.0156
0.0454
0.0167
33.8
* The exposure point for lead is the arithmetic average as
opposed to the 95% upper confidence limit concentration as is
recommended for the lead uptake/biokinetic model.
25
-------
Table 6-2
Potential Contaminant* of Concern
Upper Floridan Aquifer
Chemical
Aluminum
Arsenic
1, 1-Dichloroethane
1,1-
Dichloroethylene
1,2-
Dichloroethylene
Ethylbenzene
Iron
Lead
Manganese
Methylene Chloride
Exposure
Point
(ppm)
0.294
0.0418
0.292
0.354
0.0348
0.0923
3.09
0.0027
0.0619
0.106
Chemical
Naphthalene
Sodium
Toluene
1,1,1-
Trichloroethane
1,1,2-
Trichloroethane
Vanadium
Vinyl Chloride
Total Xylenes
Zinc
Exposure
Point
(ppm)
0.0740
29-. 91 -
2.35
0.0377
0.0053
0.0275
0.0302
0.377
1.74
26
-------
TABLE 6-3
SUMMARY OF EXPOSURE PATHWAYS
FOR THE GROUNDWATER
Future O«« Condition/Onsite Woyker
Ingestion of groundwater from the surficial aquifer
Ingestion of groundwater from Upper Floridan aquifer
Future Use Conditions/Onaite Resident
Ingestion of groundwater from the surficial aquifer
Ingestion of groundwater from Upper Floridan aquifer
Dermal contact with surficial aquifer water while
showering
Dermal contact with Upper Floridan aquifer water while
showering
Inhalation of surficial aquifer contaminants while
showering
o Inhalation of Upper Floridan aquifer contaminants while
showering
27
-------
TABLE 6-4
Assumptions Used to Estimate Exposure via
Ingestion of Groundwater
Parameter Future Use Worker Future Use Resident
Chemical
Concentrations in
Water
Ingestion Rate
(L/day)
Exposure Frequency
(days /year)
Exposure Duration
(years)
Body Weight (kg)
Average Time ( days )
Noncarcinogens
Carcinogens
see Table 9, Page p-72, Appendix P,
Areawide Groundwater Remedial
Investigation/Risk Assessment (4/92)
1
250
30
70
10,950
25,550
2
365
30
70
10,950
25,550
28
-------
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).
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure to
contaminant(s) of concern exhibiting noncarcinogenic effects.
RfDs, expressed in units of mg/kg-day, are estimates of lifetime
daily exposure levels for humans, including sensitive
individuals. Estimated intakes of contaminant(s) of concern
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).
The applicable route-specific slope factors and reference doses
for the chemicals of concern can be found in Tables 6-5 and 6-6.
As an interim procedure, until more definitive EPA guidance is
established, Region IV has adopted a toxicity equivalency
approach (TEF) methodology for evaluating polynuclear aromatic
hydrocarbons (PAHs). This methodology is based on each
compound's relative potency to the potency of benzo(a)pyrene.
The TEFs used to evaluate the carcinogenic PAHs are:
Compound TEF
Benzo(a)pyrene 1.0
Benzo(a)anthracene 0.1
Benzo(b)flouranthene 0.1
Benzo(k)flouranthene 0.1
Chrysene 0.01
Dibenzo(a,h)anthracene 1.0
Ideno(l,2,3-c,d)pyrene 0.1
6.1.4 Risk Characterization
For carcinogens, risks are estimated as the incremental
probability of an individual developing cancer over a life-time
as a result of exposure to the carcinogen. Excess life-time
cancer risk is calculated from the following equation:
Risk = CDI x SF where:
risk = a unit less probability (e.g., 2 x 10'5) of an individual
developing cancer;
CDI = chronic daily intake averaged over 70 years (mg/kg-day) ;
SF = slope-factor, expressed as (mg/kg-day)"1
29
-------
TABLE 6-5
Summary of Chronic RfDs and Slope Factors
Chemical of Concern
Antimony
Arsenic
Beryllium
Bis ( 2 -chloroethyl ) ether
Bis ( 2 -ethy Ihexyl ) phthalate
Cadmium
Chromium
1, 1-Dichloroethane
1 , 1-Dichloroethene
1 , 2 -Dichloroethene
gamma Chlordane
Manganese
Methylene chloride
Naphthalene
Toluene
1,1, 1-Trichloroethane
1,1,2 -Trichloroethane
Vanadium
Vinyl Chloride
Zinc
Reference
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
HEAST
IRIS
HEAST
IRIS
IRIS
IRIS
IRIS
HEAST
IRIS
HEAST
HEAST
HEAST
Oral Toxicity
RfD
(mg/kg/
day)
4E-4
3E-4
5E-3
NA
2E-2
5E-4
5E-3
1E-1
9E-3
2E-2
6E-5
1E-1
6E-2
4E-3
2E-1
9E-2
4E-3
7E-3
NA
3E-1
SF
(1/mg/kg/
day)
NA
1.-75
4.3
1.1
1.4E-2
NA
NA
NA
6E-1
NA
1.3E-1
NA
7.5E-3
NA
NA
NA
5.7E-2
NA
1.9
NA
30
-------
TABLE 6-6
Summary of Chronic RfDs and Slope Factors
Chemical of
Concern
Bis (2-chloroethyl)
ether
Bis ( 2 -ethylhexyl )
phthalate
1, 1-Dichloroethane
1, 1-Dichloroethene
1 , 2 -Dichloroethene
Methylene Chloride
Naphthalene
1,1,1-
Trichloroethane
1.1,2-
Trichloroethane
Toluene
Vinyl Chloride
Reference
IRIS
IRIS
HEAST
IRIS
HEAST
HEAST
HEAST
IRIS
HEAST
HEAST
Inhalation Toxicity
RfD
(mg/m3)
NA
7E-02
5E-01
1E-01
1.2E-01
3E+00
2.4E-02
1E+00
1.4E-02
2E+00
NA
RfD
(ug/m3)
NA
7E+01
5E+02
1E+02
1.2E+02
3E+03
2.4E+01
1E+03
1.4E+01
2E+03
NA
SF
l/(ug/m3)
0.00033
0.000004
NA
NA
NA
0.00000047*
NA
NA
0.000016
NA
0.000084
* The slope factor
whereas the RfDs are
for Methylene Chloride is referenced to IRIS,
referenced to HEAST.
31
-------
These risks are probabilities that are generally expressed in
scientific notation (e.g., IxlO'6 or IE'6). An excess lifetime
cancer risk of 1x1 CT6 indicates that, as a reasonable maximum
estimate, an individual has a 1 in 1,000,000 additional chance of
developing cancer as a result of site-related exposure to a
carcinogen over a 70-year lifetime under the specific exposure
conditions at a site. The National Contingency Plan (NCP) states
that sites should be remediated to chemical concentrations that
correspond to an upper-bound cancer risk to an individual not
exceeding IxlO"6 to IxlO"4 excess lifetime risk.
The potential for noncarcinogenic effects is evaluated by
comparing an exposure level over a specified time period (e.g.,
life-time) with a reference dose derived for a similar exposure
period. The ratio of exposure to toxicity is called a hazard
quotient (HQ). By adding the HQs for all contaminant(s) of
concern that affects the same target organ (e.g., liver) within a
medium or across all media to which a given population may
reasonably be exposed, the Hazard Index (HI) can be generated.
The HQ is calculated as follows:
Non-cancer HQ = CDI/RfD where:
GDI = Chronic Daily Intake
RfD = reference dose; and
CDI and RfD are expressed in the same units and represent the
same exposure period (i.e., chronic, subchronic, or short-term).
The level of confidence that one has in the information produced
by the risk characterization process is dependent on the validity
of the information used in previous stages of the risk
assessment. Although uncertainties are inherent in all four
stages of a risk assessment, the most significant uncertainty in
this assessment is probably associated with the toxicity
assessment for carcinogenic PAHs and arsenic and the evaluation
of the dermal absorption exposure route.
Lifetime cancer risks were estimated for all of the carcinogenic
chemicals of potential concern at the Peak Oil/Bay Drums Site.
The only significant risks as defined by the U.S. EPA (1990),
e.g. risk 3» 10"6, that were found associated with groundwater
contamination at this site in the future use scenarios were to
onsite workers and residents. The pathway that poses risk to the
future onsite workers is the ingestion of groundwater from the
surficial and Upper Floridan aquifers. For the future onsite
residents, however, there are more pathways; ingestion of
groundwater from both the surficial and Upper Floridan aquifers,
as well as dermal absorption and inhalation while showering with
groundwater from the surficial and/or Upper Floridan aquifers.
32
-------
These receptors, chemicals, and resultant cancer risks are
summarized in Table 6-7.
The hazard indices due to ingestion of surficial aquifer and
Uppers Floridan water for both future use scenarios are greater
than 1.0. Additionally, the hazard indices due to inhalation and
dermal absorption while showering with surficial aquifer water
are also greater than 1.0. The results can be seen in Table 6-8.
The area-wide groundwater risk assessment did not address current
exposure since onsite groundwater is not currently being used.
However, the risks associated with possible future expos'ure 'for
workers or residents exceeds the risk range for both the shallow
aquifer and deeper Floridan Aquifer, the current source of
municipal water supplies in the area. For this reason, actual or
threatened releases of hazardous substances from the groundwater,
if not addressed by implementing the response action selected in'
this ROD, will continue to contaminate the groundwater and may
present an imminent and substantial endangerment to the public
health, welfare or the environment.
6.2 Environmental Risks
The environmental risks at this site will be addressed in a
separate study (Area-wide Wetlands Impact Study). This study
evaluates the ecological status of the wetlands associated with .
the Bay Drums, Peak Oil and Reeves Southeastern Sites. The
results of this study will be contained in the Area-Wide Wetlands
Impact Study Report. The wetlands associated with these three
sites will be addressed in a separate Record of Decision.
7.0 Description of Remedial Alternatives
This section of the ROD presents an analysis of the different
options which are available to achieve the remedial objectives at
the site. The developed alternatives are specific to the
southern surficial aquifer and the Upper Floridan Aquifer. The
northern surficial aquifer underlies the Reeves Superfund Site
and since the contamination in the northern surficial aquifer is
different from the contamination in the southern surficial
aquifer, it will be addressed in a separate ROD. This ROD
addresses the southern surficial and the Upper Floridan aquifers.
This section of the ROD presents a summary of each alternative
described in the FS report.
Southern Surficial Acruifer
Alternative No. 1 - No Action
Alternative No. 2 - Containment
Alternative No. 3 - Active Restoration
33
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TABLE 6-7
CANCER RISK BY INDIVIDUAL PATHWAY
SCENARIO/EXPOSED
POPULATION
RISK FOR
PATHWAY
CHEMICAL OF CONCERN
RISK FOR
CHEMICAL
FUTURE USE - ONSITE WORKERS
Ingestion,
surficial aquifer
Ingestion,
Floridan aquifer
9.46E-03
1.44E-03
1, 1-Dichloroethene
Vinyl Chloride
Arsenic
Bis(2-
chloroethyl ) ether
Methylene chloride
1,1,2-
Trichloroethane
1, 1-Dichloroethene
Vinyl Chloride
Arsenic
Methylene chloride
1,1,2-
Trichloroethane
9.16E-03
1.33E-04
8.81E-05
5.81E-05
2.04E-05
3.73E-06
8.91E-04
2.41E-04
3.07E-04
3.33E-06
1.27E-06
FUTURE USE - ONSITE RESIDENT
Ingestion,
surficial aquifer
Ingestion,
Floridan aquifer
2.76E-02
4.21E-03
1, 1-Dichloroethene
Vinyl Chloride
Arsenic
Bis (2-
chloroethyl) ether
Methylene chloride
1,1,2-
Trichloroethane
Bis{2-
ethylhexyl ) phthalate
gamma Chlordane
1 , 1-Dichloroethene
Vinyl Chloride
Arsenic
Methylene chloride
1,1,2-
Trichloroe thane
2.67E-02
3.89E-04
2.57E-04
1.70E-04
5.95E-05
1.09E-05
1.71E-06
1.59E-06
2.6E-03
7.03E-04
8.96E-04
9.73E-06
3.7E-06
34
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TABLE 6-7 (CONT. )
CANCER RISK BY INDIVIDUAL PATHWAY
SCENARIO/EXPOSED
POPULATION
Inhalation while
showering,
surficial aquifer
Inhalation while
showering,
Floridan aquifer
Dermal absorption
while showering,
surficial aquifer
Dermal absorption
while showering,
Floridan aquifer
RISK FOR
PATHWAY
5.03E-03
5.67E-04
8.2E-04
9.17E-05
CHEMICAL OF CONCERN
1 , 1-Dichloroethene
Vinyl Chloride
Bis(2-
chloroethyl ) ether
Methylene chloride
1,1,2-
Trichloroethane
1, 1-Dichloroethene
Vinyl Chloride
Methylene chloride
1,1,2-
Trichloroethane
1, 1-Dichloroethene
Vinyl Chloride
Bis(2-
chloroethyl) ether
1, 1-Dichloroethene
Vinyl Chloride
Arsenic
RISK FOR
CHEMICAL
4.97E-03
4.48E-05
6.04E-06
8.26E-06
5.22E-06
4.83E-04
8.11E-05
1.35E-06
1.77E-06
8.09E-04
5.84E-06
3.08E-06
7.86E-05
1.06E-05
2.03E-06
35
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TABLE 6-8
HAZARD INDEX BY INDIVIDUAL PATHWAY
SCENARIO/EXPOSED
POPULATION
RISK OF
PATHWAY
CHEMICAL*
RISK OF
CHEMICAL
FUTURE USE - ONSITE WORKERS
Ingestion, surficial
aquifer
Ingestion, Floridan
aquifer
9.2
2.3
Antimony
Arsenic
Chromium
1, 1-Dichloroethene
1 , 2 -Dichloroethene
Methylene chloride
Naphthalene
Toluene
1,1,1-
Trichloroethane
Zinc
Arsenic
1 , 1-Dichloroethane
Naphthalene
Toluene
5.45E-01
3.91E-01
1.32E-01
3.96
2.92E-01
1.06E-01
8.37E-01
7.09E-01
6.87E-01
1.1
1.36
3.85E-01
1.81E-01
1.15E-01
FUTURE USE - ONSITE RESIDENT
Ingestion, surficial
aquifer
Ingestion, Floridan
aquifer
26.8
6.6
-
1 , 1-Dichloroethene
1 , 2 -Dichloroethene
1, 1-Dichloroethane
Zinc
Naphthalene
Toluene
1,1,2-
Trichloroethane
Ant imony
Arsenic
Cadmium
Chromium
Manganese
Mercury
Methylene chloride
1,1,1-
Trichloroethane
Vanadium
1 , 1-Dichloroethene
Arsenic
Naphthalene
Toluene
Vanadium
Zinc
1.16E+01
8.51E-01
1.70E-01
3.22
2.44
2.07
1.11E-01
1.59
1.14
2.86E-01
3.86E-01
1.49E-01
1.62E-01
3.09E-01
2.01
1.85E-01
1.12
3.98
5.29E-01
3.36E-01
1.12E-01
1.66E-01
36
-------
TABLE 6-8 (CONT.)
HAZARD INDEX BY INDIVIDUAL PATHWAY
SCENARIO/EXPOSED
POPULATION
Inhalation while
showering, surficial
aquifer
Inhalation while
showering, Floridan
aquifer
Dermal absorption
while showering,
surficial aquifer
Dermal absorption
while showering,
Floridan aquifer
RISK OF
PATHWAY
4
0.5
5.1
0.81
CHEMICAL*
I , 1 -Dichloroethene
1 , 2 -Dichloroethene
Naphthalene
1,1,1-
Trichloroethane
Toluene
Toluene
I , 1 -Dichloroethene
Naphthalene
1,1,1-
Trichloroethane
RISK OF
CHEMICAL
2.32
1.55E-01
5.77E-01
3.55E-01
4/60E-01
3.8
3.49E-01
6.29E-01
1.4E-01
Chemicals are ranked in descending order according to risk
presented. Only chemicals with hazard indices greater than
0.1 are presented.
37
-------
. Upper Floridan Aquifer
Alternative No. I -No Action
Alternative No. 2 - Active Restoration
Southern Surficial Aquifer
7.1 Alternative No. 1: Mo Action
In the No Action alternative, no further remedial action on the
groundwater would be taken. While EPA guidance allows
environmental monitoring in the no action alternative, no
measures may be taken to reduce the potential for exposure
through the use of institutional controls, containment,
treatment, or removal of contaminated groundwater. This
alternative does not meet the remedial action objectives for
preventing dermal contact or ingestion. As required by SARA, the
no action alternative provides a baseline for comparison with
other alternatives that provide a greater level of response.
The no action alternative does not include the treatment of
groundwater, but purely groundwater monitoring and five-year
reviews. The major components of this alternative include:
o Groundwater monitoring
o Five-year reviews
The primary applicable or relevant and appropriate requirement
(ARAR) for this alternative is the treatment technique action
level for contaminants in groundwater from the Safe Drinking
Water Act (SDWA). If no action is taken to treat the
groundwater, both organic and inorganic compounds in the
groundwater would continue to exceed MCLs and/or FMCLs. For this
reason, Alternative No. 1 does not meet ARARs.
The total present worth cost of this alternative is $153,000.
7.2 Alternative Mo. 2: Containment
This alternative includes construction of a slurry wall around
the Bay Drums Site in conjunction with a slurry wall which would
encompass the Peak Oil Site as designated in the selected remedy
chosen in the Peak Oil Site Source ROD, Operable Unit 1. The
slurry wall around the Peak Oil Site will already be in place at
this time. The containment alternative proposes dewatering the
areas contained within the Peak Oil and Bay Drums slurry walls.
Groundwater extracted from the aquifer would be treated by air
stripping and carbon polishing and then discharged to a local
POTW. The main components of this alternative include:
38
-------
o Construction of a slurry wall around the Bay Drums
Site.
o Extraction of groundwater within the two slurry walls.
o On site treatment of extracted groundwater by air
stripping and carbon polishing.
o Discharge to local POTW.
The proposed slurry wall would not contain all of the
contaminated groundwater, thus three additional wells would be
necessary outside the slurry walls.
Summary of Remedial Action Alternative
Alternative 2 would not be totally protective of human health and
the environment because only the impacted groundwater within the
slurry walls is removed and treated. The dewatering scenarios
for the two southern surficial aquifer areas would maintain a net
inward hydraulic gradient into the slurry wall area. Therefore,
groundwater would not migrate out of the slurry wall area.
However, there may be impacted groundwater outside the slurry
walls which would not be extracted and treated.
Because the area within the slurry walls cannot by completely
dewatered, immediate compliance with chemical-specific
groundwater quality ARARs may not be attained. However, the
removal of all extractable groundwater minimizes potential
exposure pathways. Emissions of VOCs from the air stripper
process would be required to comply with action-specific ARARs.
The long-term effectiveness of this alternative would be achieved
by dewatering the area within the slurry wall. Five year reviews
of the site would be conducted for at least a 10-year period.
The short-term effectiveness of this alternative would be
achieved by emissions from the air stripping process meeting
permit requirements. Some hazards are present to workers who are
associated with the treatment system operations, but these are
typical hazards that can be guarded against by compliance with
health and safety precautions. -Environmental risks would not
increase.
Alternative 2 would be easily implemented. The administrative
implementability would be dependent upon the ability to obtain
necessary access agreements and appropriate POTW discharge
approvals. An air permit would not be required but the air
stripper must meet the substantive air requirements. All
technologies and services are readily available.
The total present worth cost of this alternative is $2,779,000.
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7.3 Alternative No. 3: Active Restoration
The active restoration alternative is divided into four
subalternatives which provide a variety of treatment and
discharge options for the impacted groundwater.
7.3.1 Alternative No. 3A
This alternative would include construction of a slurry wall
around the Bay Drums Site in conjunction with a slurry wall which
will encompass the Peak Oil Site as designated in the se.lected
remedy chosen in the Peak Oil Site Source ROD, Operable Unit 1.
The extracted water would be treated for heavy metals by chemical
precipitation and for VOCs by air stripping and activated
liquid-phase carbon polishing. Treated groundwater would be
discharged by on-site spray irrigation and/or recharge into the
surficial aquifer at both sites. As in Alternative 2, three
extra extraction wells would be necessary so that all of the
contaminated groundwater can be treated. The main components of
this alternative include:
o Construction of a slurry wall around the Bay Drums
site.
o Groundwater extraction via extraction wells.
o Chemical precipitation process for removal of heavy
metals.
o Air stripping for removal of VOCs.
o Carbon polishing for removal of semi-volatiles and
remaining organic compounds.
o Discharge by on-site spray irrigation/recharge.
o Groundwater monitoring.
Summary of Remedial Action Alternative
Alternative 3A would be protective of human health and the
environment because the impacted groundwater would be extracted
and treated. Also, the slurry wall would contain most of the
contaminants, and thus migration of the contained contaminants
would be minimal.
In order for the treatment system to produce effluent which would
comply with chemical-specific groundwater quality ARARs, a
treatability study must be conducted during the remedial design.
Emissions of VOCs from the air stripping process would be
required to comply with action-specific ARARs.
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This alternative would achieve high long-term effectiveness
because low residual risk remains after remedial action is
complete. Five-year reviews of the area would be conducted for
at least a 10-year period.
The reduction of toxicity, mobility and volume would be
accomplished by treating the groundwater by a chemical
precipitation process, air stripping and activated liquid-phase
carbon. Following treatment of the impacted water, the residual
sludge produced would be required to be disposed at an off-site
facility. Also produced are air emissions which will contain
VOCs. This alternative satisfies the statutory preferences 'for
treatment by SARA.
This alternative would achieve high short-term effectiveness.
Annual monitoring throughout the treatment period would be
conducted to verify chemical concentrations exceeding cleanup
goals are not migrating. Emissions from the air stripping
process would be required to meet permit requirements.
Alternative 3A would be easily implemented.
The total present worth cost of the alternative is $4,691,000.
7.3.2 Alternative No. 3B
This alternative involves implementation of a groundwater
extraction and treatment system. Groundwater would be treated
for heavy metals and VOCs by chemical precipitation and air
stripping. Following initial treatment, a wetlands would be
constructed to remove trace concentrations of volatiles,
semi-volatiles and heavy metals for subsequent discharge by
either on-site spray irrigation/recharge or to on-site surface
waters. The main components of this alternative include:
o Groundwater extraction via extraction wells.
o Implementation of Peak Oil site source ex-situ
alternative (Operable Unit 1). Includes a below-ground
groundwater extraction system and infiltration system
within the Peak Oil slurry wall.
o Chemical precipitation process for removal of heavy
metals.
o Air stripping for removal of VOCs.
o Constructed wetlands for polishing of trace heavy
metals and organic compounds.
o Discharge by on-site spray irrigation/recharge/surface
water.
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o Implementation of groundwater monitoring program.
Summary of Remedial Action Evaluation
Alternative 3B would be protective of human health and the
environment because the impacted groundwater would be pumped and
treated, thus reducing the risk from contact with and/or
ingestion of the groundwater.
This alternative may comply with chemical-specific groundwater
quality ARARs at completion of the remedial action. In order for
the treatment system to produce effluent which would comply with
chemical-specific groundwater quality ARARs, a treatability study
must be conducted during the remedial design. Water discharged
by spray irrigation, groundwater recharge and surface water
discharge must comply with applicable surface and groundwater
standards. Emissions of VOCs from the air stripping process
would be required to comply with action-specific ARARs.
This alternative would achieve high long-term effectiveness
because little residual risks remain after the remedial action is
complete. Five year reviews would be conducted for at least a
10-year period.
The reduction of toxicity, mobility and volume would be
accomplished by installing a groundwater extraction and treatment'
system. The concentrations of VOCs, SVOCs and metals would be
reduced. The residual sludge produced in the treatment of the
impacted water would require disposal at an off-site facility.
Also produced are emissions which would contain VOCs. This
alternative satisfies the statutory preference for treatment by
SARA.
This alternative would achieve high short-term effectiveness.
Annual monitoring would be performed to keep track of the
contaminant levels in the effluent. Environmental and human
risks would not increase. Remediation would continue until
remedial action cleanup goals are achieved.
The alternative would be technically implementable. Chemical
precipitation and air stripping are standard techniques, but the
constructed wetland is less common and may involve some startup
time. All technologies and services are readily available.
The total present worth cost of the alternative is $3,901,000.
7.3.3 Alternative No. 3C
Alternative 3C is identical to Alternative 3B except that,
following the removal of volatiles by air stripping, the water
would be polished for VOCs by liquid-phase carbon followed by ion
exchange for heavy metals polishing. Groundwater extracted from
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the Peak Oil Site would be pretreated for oil if necessary by an
oil/water separator. The treated water would be either
discharged by spray irrigation/recharge or discharged to surface
water. Groundwater from monitoring wells and influent/effluent
from the treatment system would be sampled throughout the active
treatment period. The main components of this alternative
include:
o Groundwater extraction via extraction wells.
o Implementation of Peak Oil site source ex-situ
alternative (Operable Unit 1). Includes a below-ground
groundwater extraction system and infiltration system
within the Peak Oil slurry wall.
o Chemical precipitation process for removal of heavy
metals.
o Carbon polishing for removal of semi-volatiles and
other organic compounds.
o Ion exchange for heavy metals polishing.
o Discharge by on-site spray irrigation/recharge.
o Implementation of groundwater monitoring program.
Summary of Remedial Alternative Evaluation
Similar to Alternatives 3A and 3B, this alternative would be
protective of human health and the environment because the
impacted groundwater would be pumped and treated, reducing risk
to humans from potential ingestion of and/or contact with the
contamination.
Compliance with ARARs for this alternative is the same as
Alternative 3B. A treatability study would be performed to
formulate a treatment system in which the effluent meets the
applicable discharge standards. Compliance with groundwater and
surface water standards must be demonstrated. Emissions of VOCs
from the air stripping process would be required to comply with
action-specific ARARs.
The reduction of toxicity, mobility and volume would be
accomplished by groundwater extraction and treatment as discussed
in Alternative 3A. Extracted groundwater would be treated by a
chemical precipitation process, air stripping, activated liquid-
phase carbon and ion exchange. Following treatment of the
impacted water, a residual sludge would be produced which will
contain VOCs. This alternative satisfies the statutory
preference for treatment by SARA.
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The short term effectiveness of this alternative is the same as
Alternative 3A. Groundwater modeling indicated that, with the
proposed groundwater extraction system, contaminants can be
controlled and removed from the aquifer. The estimated
remediation time for this alternative is 10 years.
Alternative 3C would be easily implemented, and all technologies
and services are readily available. The administrative
implementability would be dependent upon the ability to obtain
necessary access agreements and approval for discharge options.
The present net worth cost of this alternative is $5,026,000.
7.3.4 Alternative No. 3D
This alternative includes extraction of groundwater followed by
air stripping and carbon polishing. Groundwater from the Peak
Oil Site will be pretreated for oil by an oil/water separator, if
necessary. Treated water that is not returned to the Peak Oil
Site for recharge would be discharged to the POTW. Groundwater
monitoring wells and influent/effluent from the treatment system
will be sampled throughout the active treatment period. The
major components of the alternative include:
o Groundwater extraction via extraction wells.
o Implementation of Peak Oil Site Source in-situ
alternative (Operable Unit 1).
o Air stripping for removal of VOCs.
o Carbon polishing for removal of semi-volatiles and
other organic compounds.
o Discharge to local POTW.
o Implementation of groundwater monitoring program.
Summary of Remedial Action Evaluation
Similar to the other subalternatives (3A, 3B, and 3C), this
alternative would be protective of human health and the
environment because the impacted groundwater would be pumped and
treated, minimizing the risk of potential ingestion of and/or
contact with contaminated groundwater.
Compliance with ARARs for this alternative is the same as
Alternative 3A. A treatability study must demonstrate that the
effluent meets applicable discharge standards. Treated water
effluent would comply with pollutant discharge criteria
established by the POTW. Any emissions of VOCs would comply with
action-specific ARARs.
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The reduction of toxicity, mobility and volume would be
accomplished by extraction and treatment of the groundwater. The
treatment system would significantly reduce the concentrations of
VOCs and SVOCs currently in the aquifer by air stripping and
activated liquid-phase carbon. This alternative satisfies the
statutory preference for treatment by SARA.
The short-term effectiveness of this alternative is the same as
Alternative 3A. Chemical fate and transport modeling
demonstrates that, with the groundwater extraction system,
chemicals of concern can be controlled and removed from the
aquifer. The remediation period for this alternative is"
estimated to be approximately 10 years.
This alternative would be easily implemented, all technologies
and services are readily available. The administrative
implementability would be dependent upon the ability to obtain
access agreements and appropriate approval to discharge to a
POTW.
The total present worth cost of the alternative is $2,613,000.
Upper Floridan Aquifer
7.4 Alternative No. 1: No Action
In the No Action alternative, no further remedial action on the
groundwater in the Upper Floridan Aquifer would be taken. While
EPA guidance allows environmental monitoring in the no action
alternative, no measures may be taken to reduce the potential for
exposure through the use of institutional controls, containment,
treatment, or removal of contaminated groundwater. This
alternative does not meet the remedial action objectives for
preventing dermal contact or ingestion. As required by SARA, the
no action alternative provides a baseline for comparison with
other alternatives that provide a greater level of response.
The no action alternative does not include the treatment of
groundwater, but purely groundwater monitoring and five-year
reviews. The major components of this alternative include:
o Groundwater monitoring
o Five-year reviews
Summary of Remedial Action Evaluation
Without treatment of the groundwater in the aquifer, protection
of human health and/or the environment would not be achieved.
The primary applicable or relevant and appropriate requirement
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(ARAR) for this alternative is the treatment technique action
level for contaminants in groundwater from the Safe Drinking
Water Act (SDWA). If no action is taken to treat the
groundwater, both organic and inorganic compounds in the
groundwater would continue to exceed MCLs and/or FMCLs. For this
reason, Alternative No. 1 does not meet ARARs.
The total present worth cost of this alternative is $183,000.
7.5 Alternative Mo. 2: Active Restoration
In this alternative a groundwater extraction system would be
installed and implemented, and extracted groundwater would be
treated for volatiles by air stripping and carbon polishing.
Discharge of the treated water would be to the South Wetland.
Groundwater monitoring would ensure that cleanup goals are being
met. The main components of this alternative include:
o Groundwater extraction via extraction wells.
o Air stripping for removal of VOCs.
o Carbon polishing for removal of organic compounds.
o Discharge to surface water (South Wetland).
Summary of Remedial Action Alternative
Alternative 2 would provide protection of human health and the
environment by pumping and treating impacted groundwater, thus
reducing potential risk of ingestion of and/or contact with
contaminated groundwater.
At the completion of remedial action, Alternative 2 would comply
with ARARs. An air stripping/carbon polishing treatability study
would be conducted to demonstrate that effluent would meet
discharge criteria. Groundwater effluent must comply with
applicable surface water discharge standards since it would be
discharged to the South Wetland.
This alternative would achieve adequate long-term effectiveness
because low residual risk remains after the remedial action is
complete.
The reduction of toxicity, mobility and volume would be
accomplished by pumping and treating the impacted groundwater.
This alternative satisfies the statutory preference for treatment
by SARA.
The alternative would achieve high short-term effectiveness
because the chemical plume would be controlled and chemical
concentrations would be reduced. Annual monitoring would be
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conducted to ensure that the contaminant plume would not migrate.
Remediation of the aquifer would continue until cleanup goals are
achieved.
This alternative would be easily implemented. The technologies
involved are standard processes which are readily available.
The total present worth cost of the alternative is $1,519,000.
8.0 Comparative Analysis of Remedial Alternatives
A detailed comparative analysis was performed on the remedial
alternatives developed during the FS and the modifications
submitted during the public comment period using the nine
evaluation criteria set forth in the NCP. The advantages and
disadvantages of each alternative were compared to identify the
alternative with the best balance among the nine criteria. A
glossary of the evaluation criteria is provided in Table 8-1.
According to the NCP, the first two criteria are labeled
"Threshold Criteria", relating to statutory requirements that
each alternative must satisfy in order to be eligible for
selection. The next five criteria are labeled "Primary Balancing.-
Criteria", the technical criteria upon which the detailed
analysis is based. The final two criteria are known as
"Modifying Criteria", assessing the public's and State agency's
acceptance of the alternative. Based on these final two
criteria, EPA may modify aspects of the specific alternative.
A summary of the relative performance of each alternative with
respect to the nine evaluation criteria is provided in the
following subsections. A comparison is made between each of the
alternatives for achievement of a specific criterion.
Southern Surficial Aquifer
8.1 Overall Protection of Human Health and the Environment
The first criterion against which each of the remedial
alternatives is analyzed in detail is that of overall protection
of human health and the environment. CERCLA mandates that
remedial actions provide this protection. Each remedial
alternative is analyzed to determine whether it will eliminate,
reduce, or control the risks identified in the Baseline RA.
The remedial alternatives are also evaluated to determine whether
unacceptable short-term or cross-media impacts will result from
implementation. Overall protection of human health and the
environment draws on the assessments of other evaluation
criteria, especially long-term effectiveness and permanence,
short-term effectiveness, and compliance with ARARs.
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Table 8-1
GLOSSARY OF EVALUATION CRITERIA
THRESHOLD CRITERIA:
Overall Protection of Human Health and the Environment -
Addresses whether or not a remedy provides adequate protection
and describes how risks posed through each pathway are
eliminated, reduced, or controlled through treatment, engineering
controls or institutional controls.
Compliance with ARARs - addresses whether or not a remedy will
meet all of the applicable or relevant and appropriate
requirements of other federal and state environmental statutes
and/or provides grounds for invoking a waiver.
PRIMARY BALANCING CRITERIA:
Long-Term Effectiveness and Permanence - refers to the magnitude
of residual risk and the ability of a remedy to maintain reliable..
protection of human health and the environment over time once
cleanup goals have been met.
Reduction of Toxicity, Mobility, or Volume Through Treatment -
addresses the anticipated performance of the treatment
technologies that may be employed in a remedy.
Short-Term Effectiveness - refers to the speed with which the
remedy achieves protection, as well as the remedy's potential to
create adverse impacts on human health and the environment that
may result during the construction and implementation period.
Implementability - the technical and administrative feasibility
of a remedy, including the availability of materials and services
needed to implement the chosen solution.
Cost - includes capital and operation and maintenance costs.
MODIFYING CRITERIA:
State Acceptance - indicates whether the State concurs with,
opposes, or has no comment on the Proposed Plan.
Community Acceptance - the Responsiveness Summary in the appendix
of the Record of Decision responds to public comments received
from the Proposed Plan public meeting and the public comment
period and shows how the Agency used these comments to make the
remedy selection.
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Protection of human health and the environment is provided by the
active restoration alternatives, Alternatives 3 A, 3B, 3C, and 3D,
by extracting and treating the groundwater, thus reducing or
eliminating the contaminants.
The containment alternative, Alternative 2, provides a lesser
degree of protection of human health and the environment since
the extraction system may not recover all areas of impacted
groundwater.
The no action alternative, Alternative 1, would not provide
adequate protection to human health and the environment.
8.2 Compliance with Applicable or Relevant »"H Appropriate
Requirements (ARAR0)
The second evaluation criterion in the detailed analysis of
alternatives is compliance with ARARs . Each remedial alternative
is assessed to determine whether it will meet the requirements
that are applicable, or relevant and appropriate, under the
federal and state environmental laws . Unless a waiver is
justified, the remedial alternative must be in compliance with
all chemical-specific, location-specific, or action-specific
ARARs.
The active restoration alternatives are expected to result in
compliance with chemical-specific ARARs at the completion of
remedial activities. All active restoration alternatives are
expected to meet action-specific ARARs for discharge of treated
water.
Alternative 2 would not meet chemical -specific ARARs because
residual groundwater in dewatered containment areas would not
comply with chemical-specific ARARs.
The no action alternative would not result in compliance with
chemical-specific ARARs. Since the no action alternative does
not meet the two "threshold criteria", it is not carried through
the remaining seven criteria.
8.3 Long-term Effectiveness and Permanence
The third evaluation criterion for the detailed analysis is the
long-term effectiveness and permanence of the remedial action.
The degree to which each remedial alternative provides a long-
term, effective, and permanent remedy is assessed, and the degree
of certainty that the alternative will be successful in achieving
the response objectives is evaluated. This assessment includes
factors such as an evaluation of the magnitude of the risks
remaining at the conclusion of remedial activities, the degree to
which treated residuals remain hazardous (considering volume,
toxicity, mobility, and propensity to bioaccumulate) , the
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adequacy and reliability of controls, and the potential exposure
pathways and risks posed should the remedial action require
replacement.
The active restoration alternatives provide long-term
effectiveness and permanence. At the completion of remediation
risks will be substantially reduced with the removal of
chemicals.
Long-term effectiveness of the containment alternative is
provided by constructing permanent slurry walls around the sites
and dewatering the surficial aquifer within the slurry walls'.
8.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
The fourth evaluation criterion for the detailed analysis is the
reduction of toxicity, mobility, or volume through treatment.
Each alternative is evaluated against this criterion to assess
the anticipated performance of the treatment technologies used in
the alternative to achieve the reduction in toxicity, mobility,
and/or volume of the principal threats. CERCLA requires that a
preference be given to treatment alternatives which reduce the
toxicity, mobility, or volume of hazardous constituents.
For the active restoration alternative, the reduction of
toxicity, mobility, and volume is accomplished by extracting and
treating contaminated groundwater. Alternatives 3B and 3C are
expected to achieve lower effluent concentrations; however, they
would generate larger quantities of sludge than Alternatives 3A
and 3D as a result of additional treatment processes needed in
order to meet surface water discharge standards.
Reduction of toxicity and volume of chemicals constituents for
the containment alternative is achieved by removing and treating
the surficial groundwater within the slurry walls. However, the
extraction system may not recover all areas of impacted
groundwater outside of the slurry walls.
8.5 Short-Term Effectiveness
The fifty criterion, short-term effectiveness, addresses the
effectiveness of the alternative during construction and
operation of the remedial action. Alternatives are evaluated
with respect to their effects on human health and the
environment, including risks to the community posed by
implementation of the action, protection of the workers during
implementation and the reliability and effectiveness of
protective measures available to the workers, potential impacts
to the environment caused by the remedial alternative and the
effectiveness and reliability of mitigative measures which could
be employed during implementation, and the time required to
achieve the final response objectives.
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The short-term effectiveness for the active restoration and
containment alternatives is high. Some minimal hazard to workers
are present due to treatment system operations. The off-site
migration of impacted groundwater is not expected to occur for
any of the active restoration alternatives.
8.6 Implementability
The sixth criterion upon which the detailed analysis of remedial
alternatives is based is implementability. This criterion
involves analysis of ease or difficulty of implementation,
considering the following factors:
1. Technical feasibility, that is, the feasibility to
reliably construct, operate, and monitor the
effectiveness of a remedial action, as well as
potential technical difficulties or unknowns associated
with construction or operation;
2. Administrative feasibility, that is, the feasibility of
obtaining permits or rights-of-way for construction or
operation, and coordinating interagency approval or
activities;
3. Availability of services and materials for a treatment
method or technology, such as the availability of
disposal capacity, off-site treatment or storage
capacity, availability of equipment or specialists, and
availability of special resources.
Alternatives 2 and 3A through 3D are technically and feasibly
implementable. These alternatives would be required to meet air
permit emissions requirements for the air stripper. Access
agreements may be required for the construction of the proposed
slurry wall in Alternatives 2 and 3A and for the groundwater
extraction systems outlined in the active restoration
alternatives. Also, approval to discharge treated groundwater
would be required for the active restoration alternatives.
8.7 Cost
The seventh criterion for detailed analysis of alternatives is
cost. Both capital and operational and maintenance (O&M) costs
are considered. The accuracy of cost estimates is generally
within the range of -30 percent to +50 percent. To facilitate
comparison of alternatives with expenditures occurring over
different time periods, all costs are presented in terms of
present worth.
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The costs for the alternatives are:
No Action
Containment
Active Restoration
8.8 State Acceptance
Alternative 1 - $153,000.
Alternative 2 - $2,779,000,
Alternative 3A - $4,691,000,
Alternative 3B - $3,901,000,
Alternative 3C - $5,026,000
Alternative 3D - $2,613,000
This criterion assesses the technical and administrative issues
and concerns the state may have regarding each of the remedial
alternatives. Many of these concerns are addressed through
compliance with applicable ARARs.
The State of Florida, as represented by the Florida Department of
Environmental Protection (FDEP), has been the support agency
during the Remedial Investigation and Feasibility Study process
for the Area-Wide Hydrological Study. In accordance with 40 CFR
300.430, as the support agency, FDEP has provided input during
this process. Based upon comments received from FDEP, it is
expected that concurrence will be forthcoming; however, a formal
letter of concurrence has not yet been received.
8.9 Community Acceptance
This criterion assesses the issues and concerns the public may
have regarding each of the remedial alternatives.
This criterion is addressed in the Responsiveness Summary,
Appendix A, of this document.
Upper Floridan Aquifer
8.10 Protection of Human Health and the Environment
If Alternative 2 is implemented, protection of human health and
the environment is provided by extracting and treating
groundwater. Chemicals of concern will be reduced or eliminated.
Thus, the risk to human health and the environment is
substantially reduced.
The no action alternative does not provide protection to human
health and the environment.
8.11 Compliance with ARARa
The active restoration alternative are expected to result in
compliance with chemical-specific ARARs at the completion of
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remedial activities. This alternative would be required to meet
ARARs for surface water discharge into the South Wetland.
The no action alternative would not result in compliance with
ch&mical-specific ARARs. Since the no action alternative does
not meet the two "threshold criteria", it is not carried through
the remaining seven criteria.
8.12 Long-Term Effectiveness and Permanence
Alternative 2 provides long-term effectiveness and permanence.
Risks at the completion of remediation will be substantially
reduced because chemicals are removed.
8.13 Reduction of Toxicity, Mobility or Volume
For the active restoration alternative, the reduction of
toxicity, mobility and volume is accomplished by extracting and
treating impacted groundwater.
8.14 Short-Term Effectiveness
The short-term effectiveness for the active restoration
alternative is high. However, VOC emissions will result from air-
stripping and minimal hazards to workers may occur during
treatment system operations.
8.15 Implementability
Alternative 2 will be required to meet the emissions requirements
of an air permit for the air stripper, an appropriate discharge
permit, and access agreements for discharge piping.
8.16 Cost
Costs for the Upper Floridan Aquifer alternatives are listed
below.
No Action - Alternative 1 - $183,000.
Active Restoration - Alternative 2 - $1,519,000.
8.17 State Acceptance
The State of Florida, as represented by the Florida Department of
Environmental Protection (FDEP), has been the support agency
during the Remedial Investigation and Feasibility Study process
for the Area-Wide Hydrological Study. In accordance with 40 CFR
300.430, as the support agency, FDEP has provided input during
this process. Based upon comments received from FDEP, it is
expected that concurrence will be forthcoming; however, a formal
letter of concurrence has not yet been received.
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8.18 Coonunity Acceptance
This criterion is addressed in the Responsiveness Summary,
Appendix A, of this document.
9.0 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 Alternative 3D, with two components of
3C (chemical precipitation for removal of heavy metals and
discharge by on-site spray irrigation/recharge) as contingencies,
as a groundwater remedy for the surficial aquifer and a modified
Alternative 2 as a groundwater remedy for the Upper Floridan
aquifer. The modification to Upper Floridan Alternative 2 is
that the treated groundwater from the Upper Floridan aquifer will
be discharged by the same means as treated groundwater from the
surficial aquifer.
At the completion of this remedy, the risk associated with the
groundwater at this site will be within EPA's acceptable risk
range of 1 x 10'6 to 1 x 10"*. EPA has determined that this risk .
range is protective of human health and the environment.
The total present worth cost of-the selected remedy, Alternative
3D for the surficial aquifer and a modified Alternative 2 for the-'
Upper Floridan aquifer, as presented in the Feasibility Study, is
estimated at $4,132,000. This cost does not reflect contingency
costs and the cost of discharging treated water from the Upper
Floridan aquifer to the POTW. In the event that the contingency
plan must be implemented, the overall cost of the remedy is
estimated to increase by $500,000. The cost of discharging
treated Upper Floridan water to the POTW is estimated to increase
the cost of the remedy as much as $1,500,000, bringing the total
estimated cost of the remedy (without contingencies) to
$5,632,000.
9.1 Groundwater Remediation
The goal of this remedial action is to restore groundwater to
meet Federal and State drinking water standards. Both the
southern surficial aquifer and the Upper Floridan Aquifer are
included in the state-wide classification of potential future
sources of drinking water. Based upon information obtained
during the remedial investigation, and the careful analysis of
all alternatives, EPA believes that the selected remedy will
achieve this goal.
Prior to implementing the groundwater remedy, as the first phase
of remedial design, the two production wells, Wells F2 and F3,
will be decommissioned and two new Floridan monitor wells will be
installed near the locations of F2 and F3. Upon completion of
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the new monitor wells, all Floridan aquifer wells at the sites
will be sampled on a quarterly basis to evaluate the level of
contamination in the Upper Floridan aquifer.
9.1.1 The major components of the aroundwater remedy for the
southern surficial aquifer and the Upper Floridan Aquifer
include:
o Groundwater extraction of both the surficial and Upper
Floridan aquifer via extraction wells.
o Implementation of the Peak Oil source control remedy
outlined in the Peak Oil/Bay Drums Record of Decision -
Operable Unit 1.
o Air stripping for removal of VOCs.
o Carbon polishing for removal of semi-volatiles and
other organic materials.
o Discharge to POTW. Groundwater will be treated to meet
Federal and State drinking water standards and/or
pollutant limits set by the local publicly owned
treatment works (POTW) prior to discharge. The treated"
water will be conveyed via discharge piping to connect
to a manhole for ultimate discharge to the POTW. A
permit from the POTW will have to be obtained in
order to discharge the treated groundwater into its
system.
o Groundwater monitoring.
As a contingency, if necessary, chemical precipitation for the
treatment of metals and discharge by either spray irrigation,
recharge, or surface water as outlined in Alternative 3C of the
Feasibility Study will be added to the remedy. For instance, if
Alternative 3D fails to meet the pretreatment requirements of the
local POTW for metals, the chemical precipitation component will
be added to the remedy. Also, in the event that a POTW permit
cannot be obtained, EPA will select an alternative discharge
method. If this occurs, the treatment system will be required to
meet the appropriate discharge standards for the selected method.
9.1.2 Extraction. Treatment and Discharge of Contaminated
Groundwater
Groundwater in the Southern Surficial and Upper Floridan aquifers
at the Bay Drums and Peak Oil Sites will be extracted, followed
by air stripping and carbon polishing. The actual extraction
system design and installation requirements will be determined
during the remedial design phase. The groundwater extraction
system for this alternative is based on the assumption that there
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will be no slurry wall around the Bay Drums Site and that the
Peak Oil source control remedy outlined in the Peak Oil/Bay Drums
Record of Decision - Operable Unit 1 will be fully implemented.
Treated water that is not returned to the Peak Oil Site for use
in the Operable Unit 1 soil flushing/bioremediation system will
be discharged to a POTW. All water discharged to the POTW will
be required to comply with applicable Federal, State, and local
standards set by the POTW.
9.1.3 Performance Standards
Because certain performance standards may not be determined until
the Remedial Design phase, the list of performance standards
outlined in this section is not exclusive and may be subject to
addition and/or modification by the Agency in the RD/RA phase.
a) Extraction Standards
A groundwater extraction rate that includes both the
southern surficial aquifer and the Upper Floridan Aquifer
will be determined during the remedial design. Groundwater
extracted from the Peak Oil site will be pretreated for oil,.
if necessary, by an oil/water separator.
b) Treatment Standards
Violations of secondary standards occur in the surficial and
Upper Floridan aquifers at'the Peak Oil/Bay Drums site.
These violations are present inside as well as outside the
property boundaries. The RI/FS data indicates that no
vertical migration of contaminants through the low
permeability layer between the surficial and the Floridan
aquifer is occurring at the site. However, secondary
standards are exceeded in on-site Floridan wells. The mode
of contaminant migration to the Floridan is posited to be
via faulty well casings of on-site production wells F2 and
F3.
In considering how these violations might impact current or
future potential use of the aquifers, EPA and FDEP evaluated
the following information:
1. A preliminary private well survey performed during the
area-wide groundwater RI/FS did not locate or identify
any potable water wells in the surficial aquifer within
a one-mile radius of the site; however, Floridan wells
used as a potable water source were identified within
the one-mile radius.
2. Southwest Florida Water Management District (SWFWMD)
publications indicate that the surficial aquifer system
is currently being used to a limited extent for lawn
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irrigation and stock water ("Groundwater Resource
Availability Inventory: Hillsborough County, Florida*
and Groundwater Quality of the Southwest Floridan
Water Management District"). The Floridan aquifer,
however, is identified as a potable water source.
3. The Hillsborough County Comprehensive Plan, Future Land
Use. Development of new residential homes within the
area of the site is unlikely due to zoning restrictions
("Future of Hillsborough County, Florida", dated July
1989) .
4. The Hillsborough County Ordinance 90-35 indicates that,
with certain limited exceptions (such as financial
hardship), anyone constructing new or modifying
existing residential, commercial or industrial
buildings within 500 feet of a County main water line
must use the public water supply system.
On the basis of the above information regarding current or
potential future use of the surficial aquifer, cleanup of
the surficial aquifer to meet secondary standards at the
Peak Oil/Bay Drums site may not be necessary. EPA and FDEP*
recommend not applying secondary standards in the surficial
aquifer at the site under the following conditions:
CONDITION 1
CONDITION 2
A thorough door-to-door private well survey shall
be performed as a task in the OU2 Remedial Design.
The information to be gathered in the well survey
includes: (1) size of private well; and (2) depth
of private well. The in-depth well survey shall
cover the same territory that was covered for the
preliminary well survey done for the Area-Wide
Groundwater RI/FS. Private wells that are in use
and are discovered in this well survey shall be
sampled for the contaminants of concern. If the
levels in the private well samples are above the
remediation goals and it is determined that the
private well contamination is related to the Peak
Oil/Bay Drums site, the users of that well must be
offered the opportunity to be connected to the
public water system at no charge.
Monitoring of replacement Floridan aquifer wells
must indicate that plugging and abandonment of the
on-site Floridan production wells (F2 and F3) is
effective in preventing continued vertical
migration of contaminants into the Floridan
aquifer where secondary standards must be met.
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The treatment standards (remediation goals) selected for the
chemicals of concern in the surficial aquifer are listed in
Table 9-1.
If during the RD phase, these conditions are not met or a
showing is made that the southern surficial aquifer is a
likely potable drinking water source, then the treatment
standards (remediation goals) for the surficial aquifer will
be the same as the treatment standards for the chemicals of
concern in the Upper Floridan aquifer. Groundwater in the
Upper Floridan aquifer is required to be remediated to MCLs
and Florida Secondary Maximum Contaminant Levels
(SMCLs (FL) ) for ethylbenzene, toluene, total xylenes,
aluminum, iron, manganese, and zinc. The remediation goals
selected for the Upper Floridan aquifer are listed in
Table 9-2.
If it can be demonstrated that concentrations of certain
constituents in the surficial and Floridan aquifers reflect
background conditions and are not a direct result from
operations at the sites, remediation of groundwater to below
background levels will not be required.
c) Discharge Standards
Discharged water from the groundwater treatment system shall-'
comply with pollutant discharge criteria established by the
POTW. Failure to obtain a discharge permit to the local
POTW will result in a discharge by alternative methods.
If EPA determines that alternative treatment is necessary,
the treatment system will be required to meet all ARARs,
potentially including but not limited to, substantive
requirements of the NPDES permitting program under the Clean
Water Act, 33 U.S.C. 1251 et seq., and all effluent limits
established by EPA. Alternative methods, determined by EPA,
may include discharge by either spray irrigation, recharge,
or surface water, as outlined in Alternative 3C of the FS.
d) Design Standards
The design, construction and operation of the groundwater
treatment system shall be conducted in accordance with all
ARARs/ including the RCRA requirements set forth in
40 C.F.R. Part 264 (Subpart F).
9.1.4 Compliance Testing
The treatment system's performance will be carefully monitored on
a regular basis. After demonstration of compliance with
performance standards, the Peak Oil/Bay Drums groundwater shall
be monitored for a minimum of five years. If monitoring
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TABLE 9-1
SURFICIAL AQUIFER REMEDIATION GOALS
Chemical
Volatiles
Acetone
Benzene
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethylene
1,2-Dichloroethylene (total)
Ethylbenzene
Methylene Chloride
Tetrachloroethylene
Toluene
Vinyl Chloride
Xylenes (total)
Semi-volatiles
Bis(2-chloroethyl)ether
Bis(2-ethylhexyl)phthalate
2-Methylphenol
Naphthalene
Inorganics
Ant imony
Arsenic
Beryllium
Chromium
Lead
Sodium
Vanadium
Cleanup Level (ppb)
3000
1
2400
3
7
70
700
5
3
1000
1
10,000
7
6
2000
100
6
50
4
100
15
160,000
240
Level Basis
RfD
MCL (FL)
RfD
MCL (FL)
MCL
MCL
MCLG '
MCL
MCL (FL)
MCLG
MCL (FL)
MCLG
CSF
MCL
RfD
F.A.C 17-770
MCL
MCL
MCL
MCL (FL)
AL
MCL (FL)
RfD
'CLEANUP LEVEL BASIS DEFINITIONS
RfD
MCL (FL)
MCL
SMCL (FL)
CSF
F.A.C.17-770 =
AL
Cleanup level is based on protection of health from the non-
cancer reference dose and future residential exposure
assumptions from the Baseline Risk Assessment.
Cleanup level is a Florida primary drinking water.MCL.
Cleanup level is a federal primary drinking water MCL.
Cleanup level is a Florida secondary drinking water MCL.
Cleanup level is a health-based number derived from the
cancer slope factor and the future residential assumptions
from the Baseline RA (represents a 10[-4] risk level).
Cleanup level is a petroleum-contaminated site cleanup
criteria as listed in the Florida Administrative Code,
Chapter 17-770.
Cleanup level is the federal action level for lead.
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TABLE 9-2
UPPER PLORIDAN AQUIFER REMEDIATION GOALS
Chemi cal
Volatiles
Acetone
Benzene
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethylene
1,2-Dichloroethylene (total!
Ethylbenzene
Methylene Chloride
Tetrachloroethylene
Toluene
Vinyl Chloride
Xylenes (total)
Semi-volatiles
Bis(2-chloroethyl)ether
Bis(2-ethylhexyl)phthalate
2-Methylphenol
Naphthalene
Inorganics
Aluminum
Ant imony
Arsenic
Beryllium
Chromium
Iron
Lead
Manganese
Sodium
Vanadium
Zinc
Cleanup Level (unb)
3000
1
2400
3
7
70
30
5
3
1000
1
20
7
6
2000
100
200
6
50
4
100
300
15
50
160,000
240
5000
Level Basis
RfD
MCL (FL)
RfD
MCL (FL)
MCL
MCL
S-MCL -(FL)
MCL
MCL (FL)
MCLG
MCL (FL)
SMCL (FL)
CSF
MCL
RfD
F.A.C 17-770
SMCL (FL)
MCL
MCL
MCL
MCL (FL)
SMCL (FL)
AL
SMCL (FL)
MCL (FL)
RfD
SMCL (FL)
'CLEANUP LEVEL BASIS DEFINITIONS
RfD
MCL (FL)
MCL
SMCL (FL)
CSF
F.A.C.17-770 =
AL
Cleanup level is based on protection of health from the non-
cancer reference dose and future residential exposure
assumptions from the Baseline Risk Assessment.
Cleanup level is a Florida primary drinking water MCL.
Cleanup level is a federal primary drinking water MCL.
Cleanup level is a Florida secondary drinking water MCL.
Cleanup level is a health-based number derived from the
cancer slope factor and the future residential assumptions
from the Baseline RA (represents a 10{-4] risk level).
Cleanup level is a petroleum-contaminated site cleanup
criteria as listed in the Florida Administrative Code,
Chapter 17-770.
Cleanup level is the federal action level for lead.
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indicates that the performance standards, as set forth in Section
9.1.3, are not being met at any time after pumping has
discontinued, extraction and treatment of the groundwater will
resume and operate until the performance standards are achieved.
However, if it becomes apparent that during the operation of the
groundwater treatment system that contaminant levels have ceased
to decline and are remaining constant at a level higher than the
treatment standards, the performance standards may be
reevaluated.
10.0 Statutory Determinations
Under its legal authority, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that achieve
adequate protection of human health and the environment. In
addition, Section 121 of CERCLA establishes several other
statutory requirements and preferences. These specify that, when
complete, the selected remedial action for this site must comply
with applicable or relevant and"appropriate environmental
standards established under federal and state environmental laws,
unless a statutory waiver is justified. The selected remedy must
also be cost effective and utilize permanent solutions and
alternative treatment technologies to the maximum extent
practicable. Finally, the statute includes preference for
remedies that employ treatment technologies which permanently and
significantly reduce the toxicity, mobility or volume of
hazardous wastes as their principle element. The following
sections discuss how the selected remedy for this site meets
these statutory requirements.
10.1 Protective of Human Health and the Environment
The selected remedy protects human health and the environment by
removing the chemicals of concern from the impacted groundwater
and treating it by air stripping and carbon polishing. The
selected remedy also reduces the risks outlined in the Baseline
RA.
10.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs)
The selected remedy of extracting the impacted groundwater of the
Southern Surficial Aquifer and the Upper Floridan Aquifer and
treating it through means of air stripping and carbon polishing
before discharging it to the local POTW will be required to
comply with all applicable or relevant and appropriate
requirements {ARARs). The ARARs are presented below:
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Federal ARARs
o Safe Drinking Water Act, 40 CFR 141.11-141.16,
141.50-141.51. The Primary Drinking Water Standards are
relevant and appropriate and were considered in the
development of alternatives.
o Endangered Species Act, 50 CFR Part 402. Regulations
regarding activities in critical habitats of threatened or
endangered species are applicable and were considered in the
development of alternatives if a site is located in a
critical area.
o Clean Air Act, National Ambient Air Quality Standards
(NAAQS), 40 CFR Part 50. The maximum primary and secondary
24-hour concentrations are relevant and appropriate and were
considered in the development of alternatives.
o Clean Water Act, 40 CFR 122-125, 307, 402 (a)(l), 403. All
of these regulations and requirements are applicable and
were considered in the various alternatives that are
required to meet water quality standards.
State ARARs
o Florida Drinking Water Standards, F.A.C. 17-550. The
drinking water standards for Class G-I and G-II aquifers are
applicable and were considered in the development of
groundwater cleanup levels.
o Florida Ambient Air Quality Standards, F.A.C. 17-2.1 and
17-2.3. Standards for ambient air quality are relevant and
appropriate and were considered in the development of
remedial alternatives.
o Florida Water Quality Standards, F.A.C. 17-3. Minimum water
quality standards are relevant and appropriate and were
considered in the development of the remedial alternatives.
o Warning Signs at Contaminated Sites, F.A.C. 17-736.
Regulations regarding the use of appropriate warning signs
are applicable and may be required at the entrances and
perimeter of the site.
o Groundwater Classes, Standards and Exemptions, F.A.C.
17-520. Classifications of aquifers and the cleanup
standards set for those different classes are applicable and
were considered in the development of groundwater cleanup
levels.
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o Florida Surface Water Quality Standards, F.A.C. 17-302.
Surface water quality standards are relevant and appropriate
and were considered in the development of groundwater
cleanup levels.
10.3 Coat Effectiveness
EPA believes that the selected remedy will reduce the risk to
human health and the environment from the groundwater at a cost
of $5,632,000. Of the alternatives evaluated which provide a
high level of long-term effectiveness, Alternative 3D for the
surficial aquifer and a modified Alternative 2 for the Upper
Floridan aquifer are the most cost effective. Of those
alternatives that are protective of human health and the
environment and comply with ARARs, EPA has determined that this
selected remedy provides the best balance of trade-offs in terms
of long-term effectiveness and permanence, reduction in toxicity,
mobility or volume through treatment, short-term effectiveness,
implementability, and cost, while also considering the statutory
preference for treatment as a principle element and considering
state and community acceptance.
The selected remedy will effectively reduce or immobilize the
contaminants in the groundwater and prevent and further direct
risk to human health.
10.4 Utilization of Permanent Solutions to the Maximum Extent
Practicable
EPA has determined that the selected remedy represents the
maximum extent to which permanent solutions and treatment
technologies can be utilized in a cost effective manner for the
groundwater operable unit at the Peak Oil/Bay Drums site. Of
those alternatives that are protective of human health and the
environment and comply with ARARs, EPA has determined that this
selected remedy provides the best balance of trade-offs in terms
of long-term effectiveness and permanence, reduction in toxicity,
mobility or volume through treatment, short-term effectiveness,
implementability, and cost, while also considering the statutory
preference for treatment as a principle element and considering
state and cornmunity acceptance.
The selected remedy will effectively reduce or immobilize the
contaminants in the groundwater and prevent further direct risk
to human health.
10.5 Preference for Treatment as a Principle Element
Both organic and inorganic constituents were identified at the
site. The selected remedy will achieve substantial risk
reduction by permanently treating and containing the
contamination. This alternative will be protective of human
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health and the environment, is cost effective, and will meet all
Federal and State requirements.
The remedy selected in this ROD provides the best balance of the
evaluation of the nine criteria EPA applies to every alternative.
Remediation is expected to continue for approximately 10 years.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for the Peak Oil/Bay Drums Site, which was
released for public comment in February 1993, identified one
alternative, southern surficial alternative 3D, as the p'referred
alternative to treat the impacted groundwater from both the
southern surficial aquifer and the Upper Floridan Aquifer. The
Proposed Plan also identified secondary drinking water standards
for ethylbenzene, toluene, total xylenes, aluminum, iron,
manganese, and zinc as cleanup goals/performance standards for
groundwater in both aquifers. Based on comments received during
the public comment period, and further discussions with FDEP, EPA
determined that the ROD should clarify the selection of
Alternative 3D, with two components of 3C as contingencies, as a
groundwater remedy for the surficial aquifer and the selection of_
a modified Alternative 2 as a groundwater remedy for the Upper
Floridan aquifer. In addition, EPA determined that prior to
implementing the groundwater remedy, the two production wells,
Wells F2 and F3, should be decommissioned as the first phase of
remedial design. These had not been outlined in the Proposed
Plan. These modifications and the justifications and conditions
for waiving the secondary standards in the southern surficial
aquifer are presented in more detail in the remainder of this
section.
Currently, groundwater data indicates that there is contamination
above remediation goals in both the southern surficial and Upper
Floridan aquifers. The goal of_remedial action at the sites is
to restore groundwater to meet Federal and State drinking water
standards. Both the southern surficial aquifer and the Upper
Floridan Aquifer are included in the state-wide classification of
potential future sources of drinking water. Based upon
information obtained during the remedial investigation, and the
careful analysis of all alternatives, EPA believes that the
selected remedy will achieve this goal. The Proposed Plan did
not include the selection of Alternative 2 for remediation of the
Upper Floridan aquifer, but based on additional consideration
developed during the public comment period and discussions with
FDEP, EPA has selected a modified Alternative 2. Hence, it has
been clarified in this Record of Decision.
In addition to active groundwater restoration, prior to
implementation of the groundwater remedy, the two production
wells, Wells F2 and F3, will be decommissioned. As the first
phase of remedial design, the two production wells will be
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decommissioned and two new Floridan monitor wells will be
installed near the locations of F2 and F3. The RI/FS data
suggests that no vertical migration of contaminants through the
low permeability layer between the surficial and the Floridan
aquifer is occurring at the site. However, primary and secondary
drinking water standards are exceeded in on-site Floridan wells.
The mode of contaminant migration to the Floridan is posited to
be via faulty well casings of on-site production wells F2 and F3.
Therefore, upon completion of the new monitor wells, all Floridan
aquifer wells at the sites will be sampled on a quarterly basis
to evaluate the level of contamination in the Upper Floridan
aquifer.
The Proposed Plan identified Florida's secondary drinking water
standards for ethylbenzene, toluene, total xylenes, aluminum,
iron, manganese, and zinc as remediation goals in both the
surficial and Upper Floridan aquifers. In the final Area-Wide
Hydrologic Feasibility Study dated October 1992, secondary
drinking water standards were excluded as ARARs. Therefore,
secondary drinking water standards were not identified as
remediation goals for the contaminants of concern in the southern
surficial and Upper Floridan aquifers. In December 1992, FDEP
identified State regulations that would require the application "
of Florida secondary drinking water standards as State ARARs.
These regulations are included in the Florida Administrative Code
(F.A.C) Chapters 17-520 and 17-550. After receiving and
reviewing information from FDEP, EPA agreed that these
regulations were State ARARs. These regulations required
lowering and/or including remediation goals for ethylbenzene,
toluene, total xylenes, aluminum, iron, manganese, and zinc.
Remediation goals for these compounds were listed in the February
1993 Proposed Plan.
During the public comment period, FDEP submitted a letter dated
April 26, 1993 clarifying its position regarding the use of
secondary drinking water standards as State ARARs. In that
letter, FDEP states that:
"Florida secondary drinking water standards, as defined in
Chapter 17-550, F.A.C., and as they apply to Class G-II
groundwater, as defined in Chapter 17-520 F.A.C., are
applicable or relevant appropriate requirements (ARARs) at
NPL sites. The criteria and standards in these rules
fulfill the initial requirements as ARARs pursuant to CERCLA
121(d)(2)(A).
"Under the FDEP's administrative rules, an existing
installation is exempt from compliance with secondary
standards "... unless the Department determines that
compliance with one or more secondary standards by such
installation is necessary to protect groundwater used or
reasonably likely to be used as a potable water source"
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(17-520.520, F.A.C.). While such an exemption is probable
at the Peak Oil/Bay Drums site under 17-520, F.A.C., the
secondary standards specified in 17-550, F.A.C., are
relevant and appropriate. In other words, FDEP must
consider exceedances of secondary standards and make further
determination as to whether those exceedances are violations
which require cleanup to the standards as part of a CERCLA
remedial action."
Violations of secondary standards occur in the surficial and
Upper Floridan aquifers at the Peak Oil/Bay Drums site. These
violations are present inside as well as outside the property
boundaries. In considering how these violations might impact
current or future potential use of the aquifers, EPA and FDEP
evaluated the following information:
1. A preliminary private wells survey performed during the
area-wide groundwater RI/FS did not locate or identify
any potable water wells in the surficial aquifer within
a one-mile radius of the site. Floridan wells used as
a potable water source were identified.
2. Southwest Florida Water Management District (SWFWMD)
publications indicate that the surficial aquifer system-
is currently being used to a limited extent for lawn
irrigation and stock water ("Groundwater Resource
Availability Inventory: Hillsborough County, Florida"
and "Groundwater Quality of the Southwest Floridan
Water Management District"). The Floridan aquifer,
however, is identified as a potable water source.
3. The Hillsborough County Comprehensive Plan, Future Land
Use. Development of new residential homes within the
area of the site is unlikely due to zoning restrictions
("Future of Hillsborough County, Florida", July 1989).
4. The Hillsborough County Ordinance 90-35 indicates that,
with certain limited exceptions (such as financial
hardship), anyone constructing new or modifying
existing residential, commercial or industrial
buildings within 500 feet of a County main water line
must use the public water supply system.
On the basis of the above information regarding current or
potential future use of the surficial aquifer, cleanup of the
surficial aquifer to meet secondary standards at the Peak Oil/Bay
Drums site may not be necessary. However, because the Floridan
aquifer is used as a potable drinking water supply, secondary
standards are required to be met in the Floridan aquifer. EPA
and FDEP will waive secondary standards in the surficial aquifer
at the site under the following conditions:
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CONDITION 1 A thorough door-to-door private well survey shall
be performed as a task in the OU2 Remedial Design.
The information to be gathered in the well survey
is as follows: (1) size of private well; and (2)
depth of private-well. The in-depth well survey
shall cover the same territory that was covered
for the preliminary well survey done for the Area-
Wide Groundwater RI/FS. Private wells that are in
use and are discovered in this well survey shall
be sampled for.the contaminants of concern. If
the levels in the private well samples are above
the remediation goals and it is determine'd that
the private well contamination is related to the
Peak Oil/Bay Drums site, the users of that well
must be offered the opportunity to be connected to
the public water system at no charge.
CONDITION 2 Monitoring of replacement Floridan aquifer wells
must indicate that plugging and abandonment of the
on-site Floridan production wells (F2 and F3) is
effective in preventing continued vertical
migration of contaminants into the Floridan
aquifer where secondary standards must be met.
Finally, the estimated cost included in the Proposed Plan did not
reflect the treatment of both aquifers, but solely the southern '
surficial aquifer. The total estimated cost of treating both
aquifers has been outlined in this Record of Decision. The total
present worth cost of the selected remedy, Alternative 3D for the
surficial aquifer and a modified Alternative 2 for the Upper
Floridan aquifer, as presented in the Feasibility Study, is
estimated at $4,132,000. This cost does not reflect contingency
costs and the cost of discharging treated water from the Upper
Floridan aquifer to the POTW. In the event that the contingency
plan must be implemented, the overall cost of the remedy is
estimated to increase by $500,000. The cost of discharging
treated Upper Floridan water to the POTW is estimated to increase
the cost of the remedy as much as $1,500,000, bringing the total
estimated cost of the remedy (without contingencies) to
$5,632,000.
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