United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-93/148
March 1993
PB94-964035
&EPA Superfund
Record of Decision:
Peak Oil/Bay Drum
(Operable Unit 3), FL
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50272-101
REPORT DOCUMENTATION 11. AEPORT NO. ~ 3. AlOCiplent'. Acnilion No.
PAGE EPA/ROD/R04-93/148
4. TItI8 ariel Subtitle 5. Report D8t8
SUPERFUND RECORD OF DECISION 03/31/93
Peak Oil/Bay Drum (Operable Unit 3), FL "6,
First Remedial Action
7. Author(s) a Performing Organization Rept. No.
9. Performing Organization Name and Add,.. 10 Project T88IcIWortI UnIt No.
11. Contract(C) or GnlnI(G) No.
(C)
(G)
12. SpoMorlng Organization Name and AcId,.. 13. Type of AIIpCII1 & PerIod Cov8l'8Cf
U.S. Environmental Protection Agency 800/800
401 M Street,'S.W.
Washington, D.C. 20460 14.
15.. Suppl8m8ntary Net..
PB94-964035
16. Ab8tract (Umlt: 200 words)
The 14.8-acre Peak Oil/Bay Drum (Operable Unit 3) site is a former drum reconditioning
facility in Brandon, Hillsborough County, Florida. Land use in the area is
predominantly industrial and undeveloped, with three wetlands areas located on and
adjacent ,to the site. The nearest residential area is located 0.4 miles east of the
site. Although not utilized currently, onsite ground wate~ is classified as a class II
aquifer; and therefore, is a viable source of ground water for future consumption.
From 1962 to 1974, Bay Drums reconditioned drums in a building on the eastern portion
of the site, and stored drums over most of the property. At that time, the onsite
wetlands covered approximately 1 acre and drained into a larger 5-acre wetlands area
about 300 feet southeast of the site. Little information exists regarding the early
years of operation at Bay Drums. It is believed that waste from the Bay Drums site was
discharged into the onsite wetland; a 1968 aerial photograph shows that the onsite
wetland had changed color, indicating a possible discharge of waste. From 1974 to
1978, the site operated under Tampa Steel Drum. In 1975, drums were observed in and
along the western edge of the onsite wetland. An aerial photograph taken in late 1977
shows significant changes at the site; the wetland, which presumably had been receiving
wastes, had been backfilled, possibly with material excavated from the southeast corner
(See Attached Page)
17. Document AnaIy8Js L D88crlptors
Record of Decision - Peak Oil/Bay Drum (Operable Unit 3), FL
First Remedial Action
Contaminated Media: soil, sediment, debris
Key Contaminants: organics (PAHs, PCBs, pesticides), metals (arsenic, chromium, lead)
b. IdeMlfiel'8lOp8n
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EPA/ROD/R04-93/148
Peak Oil/Bay Drum (Operable Unit 3), FL
First Remedial Action
Abstract (Continued)
of the site where a new pond was visible. The drainage from the site had been re-routed
to the larger wetland via an open ditch. Bay Drums resumed operations in 1978, after
Tampa Steel Drum went out of business. Aerial photographs taken in 1982 show that a new
pond had been constructed in the western portion of the original wetland (backfilled
wetland). This pond is known to have received waste from the drum reconditioning
activities, but its date of construction is unknown. Sometime between 1982 and 1984, drum
reconditioning activities ceased. Between 1984 and 1986, the Bay Drums site was operated
by Resource Recovery Associates, during which time waste roofing shingles were dumped on
the ground throughout most of the site to heights ranging from three to nineteen feet.
The intent of the company was to recycle the shingles as asphalt, but no significant
recycling ever occurred, and the site essentially operated as an unpermitted dump. In
1986, EPA required the site operator to cease bringing materials onsite and to remove
materials already located onsite. Although the owner ceased disposal operations, he never
removed the shingles. In 1989, EPA removed 70,000 yd3 of shingles and placed them off site
on Hillsborough County property, where they currently remain. An estimated 27,000 yd3 of
shingles were left onsite, some were pushed into three piles, but the remaining shingles
are present in various areas of the site at depths of 6 to 12 inches. In 1989, sampling
revealed four areas of buried drums a~d sludge. Subsequently, EPA removed and disposed of
contaminated soil, sludge, and drums offsite. This ROD addresses contaminated soil,
sediment, and debris at the Bay Drums site as, OU3. Future RODs will address ground water
at the Peak Oil and Bay Drums sites, soil and sediment at the Peak Oil site, and wetlands
at the entire site, as OUs 2, 1, and 4, respectively. The primary contaminants of concern
affecting the soil, sediment, and debris are organics, including PAHs, PCBs, and
pesticides; and metals, including arsenic, chromium, and lead.
The selected remedial action for this site includes demolishing onsite structures with
disposal of the resultant debris at .an offsite permitted landfill; erecting a security
fence around the site; dewatering surface ponds, if necessary, prior to removal of
sediment; dredging contaminated sediment and excavating lead-impacted soil which exceeds
the perfor.mance standard of 284 mg/kg, followed by onsite stabilization/solidification of
these materials with onsite disposal; conducting treatability studies to determine what
impact the presence of organic compounds and shingle fragments may have on the ability of
the stabilization/solidification process to meet performance standards; backfilling
excavated areas and surface ponds; disposing of shingle and other debris in accordance
will all applicable requirements; constructing a low permeability clay cap surrounded by a
drainage ditch over the stabilized material; placing a I-foot topsoil cover over remaining
portions of the site, with revegetation to prevent erosion; monitoring ground water; and
implementing institutional controls, including deed restrictions. The estimated present
worth cost for this remedial action is $2,680,000, which includes an estimated total O&M
cost of $20,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil and sediment cleanup goals are based upon protection of ground
water and the performance standard for the low permeability surface cap of 10-7 cm/sec or
less, and include lead 284 mg/kg and chlordane 180 mg/kg.
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RECORD OF DECISION
OPERABLE UNIT 3
BAY DRUMS SOURCE CONTROL
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
BAY DRUMS SOURCE CONTROL
OPERABLE UNIT THREE
PEAK OIL/BAY DRUMS NFL SITE
1.
DECLARATION
SITE NAME AND LOCATION
Peak Oil/Bay Drums Site
Brandon, Hillsborough County, Florida
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
Operable Unit Three 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 and Reauthorization Act of 1986 (SARA), and, to the
extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision is based on the
Administrative Record for the site.
The State of Florida, as represented by the Florida Department of
Environmental Regulation (FDER), has been the support agency during
the Remedial Investigation and Feasibility Study process for the
Peak Oil/Bay Drums site. In accordance with 40 CFR 300.430, as the
support agency, FDER has provided input during this process. Based
upon comments received from FDER, it is expected that concurrence
will be forthcoming: however, a formal letter of concurrence has
not yet been received.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTIOII OP THE REHEDY
The Peak 011 and Bay Drums sites were ranked on the National
Priorities List (NFL) as one site because of their close proximity
and indiscriminate waste disposal practices which resulted in the
contamination of adjacent surface water and groundwater. The
remedy selected by EPA for the Peak Oil/Bay Drums site will be
conducted in four separate phases, known as operable units.
Operable Unit One will address the source of contamination at the
Peak Oil site. Operable Unit Two will address the appropriate
remediation for the groundwater at both the Peak Oil and Bay Drums
sites. Operable Unit Three, presented in this Record of Decision,
will address the source of contamination at the Bay Drums site,
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which constitutes a principal threat. Finally, Operable Unit Four
will address the appropriate remediation for the wetlands
surrounding the Peak Oil, Bay Drums, and Reeves Southeastern sites.
The response action selected in this ROD addresses the principal
threats posed by Bay Drums site soils and sediments. The selected
remedy for Operable Unit Three consists of the following major
components:
o
Dredge contaminated sediments which exceed performance
standards from the pond areas and north drainage ditch
and treat in an on-site stabilization/solidification
treatment process;
o
Excavate contaminated soils which exceed performance
standards and treat in an on-site stabilization/
solidification treatment process;
o
Backfill excavated areas and surface ponds with clean
fill;
o
Dispose of treated soils and sediments on-site above the
water table;
o
Construct a low permeability clay cap over stabilized
material;
o
Demolish/dismantle all on-site structures and dispose in
an appropriately permitted off-site landfill;
o
Dispose of non-hazardous debris present at the site in an
appropriately permitted off-site landfill;
o
Dispose of shingle debris (known as the On-site Shingles)
in accordance with all applicable Federal, State, and
local requirements;
o
Construct drainage ditches as needed to prevent ponding
of water on the site;
o
Place 1 foot of topsoil over remaining portions of the
site and revegetate the site with native grasses to
prevent erosion of the cap and backfilled areas.
o
Conduct groundwater monitoring on a periodic basis in
conjunction with groundwater treatment to assess
contaminant migration;
o
Erect an eight-foot security fence with appropriately-
spaced warning signs to prevent entryi
o
Record deed notices with Hillsborough County advising
that hazardous constituents are disposed on-sitei
ii
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L__-
STATUTORY DETERXINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment 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.
Because this remedy will result in hazardous substances remaining
on-site, a review will be conducted within five years after
commencement of remedial action to ensure that the remedy continues
to provide adequate protection of human health and the environment.
f'./Iwuh 31, /773
Date
~/Y7J~
Patrick M. Tobin
Acting Regional Administrator
U.S. EPA Region IV
iii
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TABLE OF CONTENTS
I. DECLARATION i
Table of Contents iv
List of Figures vi
List of Tables vii
II. DECISION SUMMARY 1
1.0 Site Name, Location, and Description 1
2.0 Site History and Enforcement Activities 1
3.0 Highlights of Community Participation 7
4.0 Scope and Role of Operable Unit 7
5.0 Summary of Site Characteristics 8
5.1 General Site Characteristics 8
5.2 Results of Site Source Investigations 9
5.2.1 Previous Site Investigations 9
5.2.2 Site Source Remedial Investigation . . 12
6.0 Summary of Site Risks 13
6.1 Human Health Risks 13
6.1.1 Contaminants of Concern 16
6.1.2 Exposure Assessment 16
6.1.3 Toxicity Assessment 17
6.1.4 Risk Characterization 17
6.1.5 Uncertainties in Risk Assessment ... 26
6.2 Environmental Risks 26
7.0 Description of Alternatives 26
7.1 Alternative 1 - No Action 27
7.2 Alternative 2 - Containment 28
7.3 Alternative 3 - In-Situ Stabilization/
Solidification 29
7.4 Alternative 4 - Ex-Situ Stabilization/
Solidification and On-Site
Disposal 30
7.5 Alternative 5 - Ex-Situ Stabilization/
Solidification and Off-Site
Disposal 31
8.0 Comparative Analysis of Alternatives 31
8.1 Overall Protection of Human Health
and the Environment 32
8.2 Compliance with Applicable or Relevant
and Appropriate Requirements (ARARs) 34
iv
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9.0
10.0
11.0
8.3
8.4
8.5
8.6
8.7
8.8
8.9
Long-Term Effectiveness and Permanence. . . .
Reduction of Toxicity, Mobility, or Volume. .
Short-term Effectiveness. . . . . . . . . . .
Implementability . . . . . . . . . . . . . . .
Co st. . . . . . . . . . . . . . . . . . . . .
State Acceptance. . . . . . . . . . . .
Community Acceptance. . . . . . . . . . . . .
Selected Remedy. . . . . . . . . . . . . . .
9.1 Remedial Action Objectives. . . . . . . . . .
9.2 Performance Standards. . . . . . . . . . . .
Statutory Determinations. . . .
10.1 Protection of Human Health and
the Env ironment. . . . . . . . . . . . . . .
10.2 Compliance with Applicable or Relevant and
Appropriate Requirements (ARARs)
10.3 Cost Effectiveness. . . . . . . . . . . . .
10.4 Utilization of Permanent Solutions and
Alternative Treatment Technologies to the
MaxLmum Extent Practicable. . . . . . . . .
10.5 Preference for Treatment as a
Principal Element. . . . . .
. . . . . .
. . . . .
Documentation of Significant Changes
. . . .
III. RESPONSIVENESS SUMMARY
Appendix A - Cost Estimates
v
34
35
35
36
36
37
37
38
44
44
46
47
47
48
48
49
49
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Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
LIST OF FIGURES
General Site Location Map . .
Paqe
. . 2
.......
. . . .
. . 3
Site Vicinity Map . . . . . .
General Site Layout. .
. . . .
. . . . . .
. . 4
Typical Geologic Profile for the
Bay Drums Site. . . . . . . . .
Potentiometric Surface of the Upper
Floridan Aquifer. . . . . .
Areas which Exceed Remedial Action
Objectives. . . . . . . . .
Typical Cross-Section of Low
Permeability Clay Cap. . . .
.........
10
........
11
........
39
...........
41
Area to be Covered by Low
Permeability Surface Cap
.............
42
vi
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Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
LIST OF TABLES
Range of Detected Concentrations for Potential
Contaminants of Concern. . . . . . . . . . . . . .
Exposure Point Concentrations
. . . . .
Exposure Assessment for Soil, Sediment,
and Air Pathways. . . . . . . . . . .
. . . . . .
Toxicity Values for Contaminants of Concern.
Summary of Current Site Carcinogenic Risks
. . . .
Summary of Future Site Carcinogenic Risks.
Summary of Hazard Quotients. . . . .
. . . .
. . . .
Comparative Analysis of Alternatives
.......
Summary of Remedial Action Objectives for
Soi18 and Sediments. . . . . . . . . . .
. . . . .
vii
Paqe
14
18
19
20
22
23
24
33
45
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II.
DECISION SUMMARY
1.0
SITE KAKB, LOCATION, AND DESCRIPTION
The Bay Drums site is located on State Road 574 (S.R. 574) east of
Tampa, Florida in the unincorporated community of Brandon, Florida.
A general site location map is presented in Figure 1.
Specifically, the site is situated approximately 1/4 mile west of
Faulkenburg Road (Figure 2).
The 14.8 acre site is bounded on the north by the Seaboard
Coastline Railroad right-of-way, on the east by an abandoned
railroad spur line, on the south by a wetland area, and on the west
by a Tampa Electric Company (TECO) easement. Immediately east of
the railroad spur line lies the Peak Oil site with which the Bay
Drums site was co-ranked on the National Priorities List (NFL).
Located directly across S.R. 574 is the Reeves Southeastern
Galvanizing Plant NFL site, and located east of the Peak Oil site
is the Reeves Southeastern Wire property. A generalized layout of
the Bay Drums site is provided in Figure 3.
The Bay Drums site is a former drum reconditioning facility.
Although the facility is no longer operational, when the Bay Drums
site was active, drum reconditioning occurred within the buildings
on the eastern portion of the site, and drums were often stored
beneath the power lines and west to a vacant lot. In the past,
nearly all of the site property was used for drum storage, although
the active drum reconditioning area only covered approximately 2
acres in the northeast corner of the site (see Figure 3).
Prior to development in 1962, this 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 a somewhat larger (approximately 5 acre) wetland about 300
feet to the southwest. Currently, surface drainage on the northern
portion of the site is north to a ditch along the-southern edge of
the Seaboard Coastline Railroad, and the ditch then flows west.
The southern portion of the site drains to the wetland area south
of the site. The larger wetland (known as the "central wetland")
has no surficial outlet. This wetland, which was formerly distinct
from the site, is presently connected hydrologically above ground
with the Bay Drums pond, which is the southern tip of the original
on-site wetland.
2.0
SID HIS'l'ORY .AIm BHPORCEHBHT ACTIVITIBS
Bay Drums Inc. was incorporated on September 26, 1962. Few details
are known of the early days of the operation. Examination of
aerial photographs dated October 27, 1965 shows that a berm was
constructed across the southern portion of the site, crossing the
southern one-third of the on-site wetland. No standing water was
visible south of the berm.
1
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&EPA
Figure 1. General site location map - Bay Drums site.
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Figure 2., Site vicinity map - Bay Drums site.
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Aerial photographs of the site illustrate a surface drainage
connection between the Peak Oil site and the remainder of the
wetland on the Bay Drums site, north of the berm. Two possible
routes are seen in the photographs for the discharge of wastes from
the Bay Drums site: the drainage ditch north of the site, and the
remaining wetland east of the drum reconditioning area and north of
the berm. On an aerial photograph dated January 21, 1968, it was
noted that the wetland remaining on the Bay Drums site had changed
color, indicating a possible discharge of waste. In March 1968,
this wetland was sold to Benny and Lenore Genuardi (former owners
of Bay Drums).
From March 1974 to April 1978, the site was operated under
different ownership as Tampa Steel Drum. An aerial photograph
dated March 6, 1975 shows drums located in and along the western
edge of the wetland, again indicating that this area received waste
material from the site. An aerial photograph dated November 27,
1977 shows significant changes in the site. The wetland which had
presumably been receiving wastes had been backfilled, possibly with
material excavated from the southeast corner of the site where a
new pond is visible (termed in this document the "backfill pond";
the original on-site wetland north of the berm is termed the
"backfilled" wetland). The berm is no longer visible, and the
southern tip of the original wetland south of the berm (now termed
the "Bay Drums pond") appears dry. The drainage from the Peak Oil
Site had been re-routed to the central wetland via an open ditch
which was still visible during a reconnaissance of the site
performed in February 1988.
Bay Drums, Inc. resumed operations in 1978 after Tampa Steel Drum
went out of business. Aerial photography dated September 2, 1982
shows a new pond constructed in the western portion of the original
wetland (backfilled wetland). This pond (the "washwater holding
pond" or, "holding pond") is known to have received wastes from the
drum reconditioning activities, but its date of construction is
unknown. Drum reconditioning activities ceased sometime between
1982 and 1984. In 1984, the Peak Oil and Bay Drums sites were
evaluated according to the Hazard Ranking System and proposed on
the NPL with a score of 58.15. These sites were ranked on the NPL
as one Superfund site due to their close proximity and
indiscriminate waste disposal practices which resulted in the
contamination of adjacent surface water and groundwater.
Between 1984 and 1986, the Bay Drums site was operated by Resource
Recovery Aa8ociates, Inc. During this time, waste roofing shingles
were dumped on the ground throughout most of the site to heights
ranging from three to nineteen feet. The stated intent of the
company was to recycle the shingles as asphalt, but no significant
recycling ever occurred, and the site essentially operated as an
unpermitted dump. On November 12, 1986, EPA issued a CERCLA
Section 106 Order to the site operator requiring him to cease
bringing materials on-site and to remove materials already located
. on the site. Although the owner ceased disposa~ operations, he
5
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failed to remove the large amount of shingles already on the site.
EPA later conducted a fund-financed removal in 1989 to remove
approximately 70,000 cubic yards of shingles from the site prior to
beginning field activities. Following the segregation of drums and
other waste material from the shingles, the shingles were placed on
Hillsborough County property adjacent to the site, and a fence and
warning signs were erected around the shingles. These shingles are
referred to in this ROD as the Shingle Pile. These actions were
necessary in order to evaluate the extent of soil contamination at
the site.
An estimated 27,000 cubic yards of shingles were left- on':'site
because a temporarily high water table made it difficult to remove
these materials without also removing contaminated soils from the
site. Some of these materials have been pushed into three small
piles on the west side of the site (known as shingle piles 1, 2,
and 3 for sampling and risk assessment purposes), but the remaining
shingles are present in various areas of the site at depths of 6 to
12 inches. All of these shingles are referred to collectively in
this ROD as the On-site Shingles.
Sampling conducted in 1989 revealed the presence of buried drums
and sludges, which were later found to be located throughout the
entire northeast corner of the site. Additionally, three other
drum burial areas were discovered south of the site buildings on
Hillsborough County property. Later that year, EPA removed drums,
soils, and sludges contaminated with volatile and semi-volatile
organic compounds, pesticides, PCBs, and metals from the site. The
drums were decontaminated and disposed off-site, while
approximately 4,000 cubic yards of soils and other materials were
temporarily stored in a lined and covered cell which EPA built on-
site. In early 1990, EPA shipped these contaminated materials by
rail to a regulated hazardous waste disposal facility in Utah.
Between 1990 and 1992, EPA conducted an RIfFS in order to further
define site contamination, determine risks from exposure to
contaminants, and evaluate cleanup alternatives. to eliminate or
reduce site risks. The final RI Report was published in July 1992,
and the FS Report was completed in September 1992.
To date, EPA has identified approximately 400 companies who
arranged to have drums recondi tioned by or sold to Bay Drums
Company andlor Tampa Steel Drums Company. Between 1986 and 1991,
EPA issued DOtice letters to these potentially responsible parties
(PRPs) adviaing them of their potential liability. Although the
PRPs did not agree to conduct the RIfFS for the site, a group of
approximately 60 of these companies has formed a steering committee
for the purposes of negotiating a settlement with EPA for the final
cleanup at the site.
6
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3.0
HIGHLIGHTS OF COHKUHITY PARTICIPATION
In accordance with Sections 113 and 117 of CERCLA, EPA has
conducted community relations activities at the Bay Drums site to
ensure that the public remains informed concerning activities at
the site. During removal activities at the site, EPA issued press
releases to keep the public informed. There was some local press
coverage of EPA's activities, and EPA held meetings with county and
state officials to advise them of the progress at the site.
A community relations plan (CRP) was developed in 1988 anp reyised
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
in August 1992. The fact sheet detailed EPA's preferred
alternative for addressing the source of contamination (Operable
Unit Three) at the Bay Drums site. Additionally, an Administrative
Record for the site, which contains site related documents
including the RI and FS reports and the Proposed Plan for Operable
Unit Three, was made available for public review at the information
repository in the Brandon Public Library. A notice of the
availability of this Administrative Record for the Bay Drums site
was published in the Tampa Tribune on August 11, 1992 and again on
August 17, 1992.
A 30-day public comment period was held from August 13, 1992 to
September 13, 1992 to solicit public input on EPA's preferred
alternative for Operable Unit Three. Finally, EPA held a public
meeting on August 18, 1992 at the Hillsborough Community College 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 in Section III of this ROD.
This decision document presents the selected remedial action for
contaminated soils and sediments at the Bay Drums site in Brandon,
Florida, chosen in accordance with CERCLA, as amended by SARA, and
to the extent practicable, the NCP. This decision is based on the
Administrative Record for Operable Unit Three at the site.
4.0
SCOPB AItD ROLE OF OPERABLE OBIT
As with many Superfund sites, the problems at the Peak Oil/Bay
Drums site are complex. This complexity stems in part from the
various media which are contaminated and from the proximity of the
Bay Drums site to the Peak Oil and Reeves Superfund sites. As a
result, EPA organized the remedial action at the Peak Oil/Bay Drums
site into the four operable units (OUs) listed below:
o
OU One:
Contamination in the soils and sediments at
the Peak Oil site.
7
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o
OU Two:
Contamination in the groundwater 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 surrounding the
Peak Oil, Bay Drums, and Reeves Southeastern
sites.
Since contaminants of concern and other site conditipns. vary
between the sites, different remedial actions to address source
contamination problems (soil and sediment) were potentially
necessary for each. For this reason, a separate RIfFS and ROD has
been completed for addressing source problems at each of the three
sites. However, EPA elected to combine the evaluation and
remediation of wetlands and groundwater problems in the vicinity of
the three sites since the remediation of these media at anyone of
the sites would potentially impact the other two sites.
In 1989, a group of PRPs for the Peak Oil site, along with the
Reeves Southeastern Corporation, signed an administrative consent
order in which they agreed to conduct an Area-Wide Groundwater
RIfFS. EPA is currently preparing a ROD which contains a
comprehensive remediation plan for addressing groundwater
contamination at the Peak Oil and Bay Drums sites. A separate ROD
is being developed to address groundwater contamination at the
Reeves site. Wetlands problems will be addressed in a subsequent
ROD.
The principal threats to human health and the environment addressed
by the Operable Unit Three ROD are associated with current worker
exposure to contaminated soils and sediments at the Bay Drums site.
5.0
SOHHARY OF SITE CHARACTERISTICS
5.1
General 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 falling in the summer.
The general topography of the area is flat, with an average surface
elevation at the site of 37 feet above mean sea level (MSL).
Elevations in areas surrounding the site range from about 25 to 45
feet above IISL. Due to the site's elevation above MSL, tidal
surges are not likely to impact the area.
The Bay Drums site has several small ponds, and a ditch runs along
the northern side of the site. Three wetlands areas exist near the
site and are the subject of a separate Area-Wide Wetlands Impact
Investigation by EPA. The wetlands are identified as the North,
Central, and South Wetlands based on their orientation to the three
8
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1----
Superfund sites. The southern portion of the Bay Drums site slopes
gradually to the south and southwest toward the Central Wetland.
Land use in the area is either industrial or undeveloped, with the
nearest single family residential area being 0.4 miles east of the
Bay Drums facility. It is anticipated that the primarily
industrial character of the area surrounding the site will be
maintained in the future.
The groundwater system beneath the area consists of two major water
bearing units: an upper aquifer referred to as the surficial
aquifer, and the Floridan aquifer system. The surficial aquifer is
from 9 feet to 37 feet thick with a saturated thickness of about 5
to 25 feet. It is separated from the Floridan aquifer by the
Hawthorne formation, a low-permeability clay layer ranging from 15
to 40 feet thick. The surficial aquifer is hydraulically connected
to surface waters (wetlands and streams), and the flow direction
varies seasonally. Water levels also fluctuate seasonally and
change rapidly in response to rainfall and other natural
influences.
As shown in Figure 4, the Suwannee Limestone formation and the
overlying Tampa Limestone formation comprise the upper portion of
the Upper Floridan aquifer. Al though regionally the Floridan
aquifer flows to the southwest, in the site vicinity the flow
direction shifts to the northwest, possibly due to the proximity of
the site to the Tampa Bypass Canal, which reportedly cuts into the
low-permeability layer and reaches the upper Floridan aquifer in
several places. The potentiometric surface of the upper Floridan
aquifer is illustrated in Figure 5.
5.2
Results of Site Source Investiaations
5.2.1
Previous Site Investiaations
In February 1983, the Florida Department of Environmental
Regulation (FDER) conducted a sampling investigation at the site.
Water samples were collected from the washwater holding pond, the
on-site production well, and the discharge from the holding pond.
Analytical results identified the presence of heavy metals,
volatile organic compounds, and petroleum hydrocarbons at the site.
A more extenaive investigation was conducted by EPA in September
1983 duriDg which samples were collected from surface water,
sediments, 80i1s, and groundwater at the site. The results of this
investigation confirmed the results of the earlier FDER study and
revealed the presence of pesticide contamination in the storage
areas.
EPA conducted another investigation in February 1986. Samples
collected during this investigation contained high concentrations
of chlordane in surface soils, subsurface soils from the saturated
zone, and sediments. Organic compounds and elevated levels of
9
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Pigure 4. Typical qeoloqic profile for the Bay Drums site.
10
-------
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11
-------
metals (including lead and chromium) were detected in groundwater
at the site. Chlordane was also detected in a water sample taken
from the washwater holding pond.
In an April 1988 site reconnaissance visit conducted by EPA, the
volume of the shingle pile was estimated, and subsurface soils were
examined for visible contamination using a hand auger. When the
surface soils r.orthwest of the washwater pond were disturbed, a
strong odor of solvents was noted, indicating the presence of high
concentrations of solvents.
5.2.2
Site Source Remedial Investiaation
The Remedial Investigation for site source contamination was
conducted by EPA between 1990 and 1992. Samples of surface water,
sediment, soil, subsurface soils, and air were collected at the
site to determine the nature and extent of site source
contamination. A summary of the sampling results for each medium
is presented in Table 1 and discussed in more detail in the
following sections.
Soils
Surface and subsurface soils at the Bay Drums site are contaminated
with a variety of organic compounds and metals. Lead was detected
in both surface and subsurface soils throughout the site. As
indicated in Table 1, lead concentrations as high as 1,600 ppm were
detected in surface soils (0 to 2 ft. below land surface). Lead
was detected in subsurface soil samples at concentrations as high
as 2,500 ppm. Other metals such as chromium, zinc, barium, and
arsenic were also detected frequently in certain areas of the site,
but none of these were detected above remedial action objectives
( RAOs ) .
The pesticides which were most frequently detected in site soils
included DDE, ethion, and chlordane. Of these contaminants, only
chlordane exceeded RAOs for the site. It should be noted that the
chlordane value for a given sample consists of the sum of the
following seven chlordane constituents: gamma-chlordane, alpha-
chlordane, chlordene, gamma-chlordene, alpha-chlordene, trans-
nonachlor, and cis-nonachlor. .
Various volatile organic compounds such as ethyl benzene, xylene,
and seven carcinogenic polynuclear aromatic hydrocarbons (cPAHs)
were identified in soils and are ubiquitous throughout the site.
In spite of their widespread presence, none of the volatile organic
compounds or cPAHs exceeded RACs for the site.
Surface Water and Sediments
The sediments at the Bay Drums site are contaminated with heavy
metals, pesticides and PCBs, extractable organic compounds (notably
carcinogenic PAHS) and purgeable organic compounds. However, of
12
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these constituents, lead is the only contaminant which exceeded
site-specific RAOs, with concentrations ranging up to 570 ppm.
Some of the same constituents were found in surface waters at the
site, but the high concentrations of these contaminants in the on-
site sediments probably account for their presence in surface water
samples. The sediments are likely serving as a source for the
continuing release of these contaminants into the surface waters.
Air
Although no volatile organic compounds were detected above
background concentrations in air samples collected at sampling
locations on and around the Bay Drums site, pesticides were
detected at the site after the removal of shingles. Chlordane,
heptachlor, DDE, and Dieldrin were detected at levels above the
background concentrations determined during the RI. Chlordane and
its constituents were the pesticides detected at the highest
concentrations. In some instances following removal activities,
chlordane was detected in air samples and determined to be up to
1000 times the pre-shingle removal concentration. For this reason,
air monitoring during remedial activities is essential to ensure
that site workers are adequately protected and fugitive emissions
are not released from the site.
6.0
6.1
SmmARY OF SITE RISKS
Human Health Risks
A Baseline Risk Assessment was conducted by EPA as part of the RI
to estimate the health or environmental problems that could result
if the Bay Drums site were not remediated. Results are contained
in Section 6 of the Final Remedial Investigation Report for the Bay
Drums site. 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.
Generally, BPA evaluates site risks for all environmental media in
one risk dS8essment and determines cumulative risk based on total
exposure. However, due to the close proximity of the Bay Drum,
Peak Oil, and Reeves Southeastern sites, EPA is evaluating risk
posed by groundwater exposure in a separate area-wide study. Since
soils and sediments evaluated in this study are a source for the
groundwater contamination, the impact on groundwater is discussed
briefly in this risk summary.
13
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Table 1
Range of Detected Concentrations for
Potential Contaminants of Concern
Bay Drums Site
Concentration8
Chemical Surface Soils Subsurface Surface Water Sediments
(mg/kg) Soils (mg/kg) (ug/l) (mg/kg)
Arsenic 2.7 - 53 3.3 - 13 17 - 26 6 - 59
Barium 41 - 190 65 - 1400 40 - 260 14 - 120
Chromium 2.2 - 170 1.9 - 560 10 - 22 3.9 - 290
Lead 1.4 - 1600 1. 1 - 2500 4 - 99 1 - 570
Zinc 26 - 740 5.9 - 3200 590 20 - 1900
4,4'-DDE (P,P'-DDE) .033 - 1.9 .19 - 3.9 .44 .044 - 920
4,4'-DDD (P,P'-DDD) .02 - .56 -- -- .041 - 250
PCB (total)b .17 - 16 5.22 -- .46 - 2.3
Gamma-chlordane/2 .19 - 24 .31 - 5.9 -- .16 - 7.3
Alpha-chlordane/2 .15 - 60 .19 - 5.7 -- .091 - 1.9
Ethion .044 - 39 .016 - 2.7 -- .054 - 22
Dieldrin -- -- .17 .024
Aldrin -- -- -- .025 - .029
Naphthalene .065 - 3 .097 - 130 -- .12 - 23
Fluorene .079 - 6.7 .055 - 3.9 -- .13 - 3.2
Fluoranthene .091 - 120 .11 - 29 -- .22 - 20
pyrene .077 - 63 .057 - 32 -- .19 - 15
14
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Table 1
(continued)
Range of Constituent Concentrations for
Potential Contaminants of Concern
Bay Drums Site
Concentration
Chemical Surface Soils Subsurface Surface Water Sediments
(mg/kg) Soils (mg/kg) (ug/l) (mg/kg)
Benzo(b&k)fluoranthene .11 - 85 .043 - 35 -- .34 - 19
Anthracene .086 - 16 .063 - 5.5 -- 1.4 - 5.6
Benzo(a) anthracene .056 - 45 .067 - 19 -- .11 - 11
Chrysene .053 - 37 .074 - 18 -- .14 - 10
Indeno(I,2,3-cd)pyrene .31 - 14 .11 - 4.5 -- .16 - 6
Benzo(a)pyrene .048 - 40 .066 - 11 -- .085 - 9.3
Acenaphthene .08 - 6.7 .05 - 4.5 -- .092 - 3.4
Dibenzo(a, h) anthracene 1.6 - 3.1 -- -- .16 - 2
. Values are ranges of detected concentrations, except where only a single sample
constitutes the entire data set for a medium.
b PCB values represent the sum of Aroclors 1248, 1254, and 1260.
15
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6.1.1
Contaminants of Concern
In general, the site contaminants which could pose a potential
threat to human health are metals (arsenic, lead), pesticides
(chlordane, ethion), PCBs, and polynuclear aromatic hydrocarbons
(PAHs). The site media which were evaluated in the baseline risk
assessment were soil (surface and subsurface), sediments, the waste
pile (a temporary pile of contaminated soil and debris created
during a removal and later disposed off-site), on-site shingle
piles 1, 2, and 3, and ~ir. The risk associated with exposure to
on-site surface water was not evaluated due to the low l~vels of
contaminants in the surface water.
For all contaminants except PAHs, the surface soil exposure point
concentrations were based on the mean concentration detected.
However, for PAHs, which are widely distributed throughout the
site, the exposure point concentration is the 95% upper confidence
limit (UCL) of the arithmetic average. Based on the contaminant
distribution, the exposure point concentration used for the
subsurface contaminants of concern was the mean concentration
detected. The sediment exposure concentration for the site water
bodies represents the mean concentration detected if more than one
sample was collected. If only one sample was taken, this sample
data was used as the exposure point concentration. Since the air
contaminant of concern, chlordane, was detected throughout the
site, the exposure concentration is based on the UCL concentration.
The media contaminants of concern and exposure point concentrations
are contained in Table 2.
Currently, the site appears to be abandoned. Although on-site
groundwater is not being used at the present time, it is classified
as a Florida Class II aquifer and therefore is a viable source of
groundwater for future consumption. The risks associated with
exposure to groundwater are addressed in the area-wide risk
assessment, although the impact of contaminant leaching from soils
into groundwater was evaluated. Also, the site is located in an
area which is zoned for industrial uses, and zoning changes would
be necessary before development of the site for residential
purposes could occur.
6.1.2
Exoosure Assessment
The current potential exposure pathways include the exposure of on-
site worker. and a young child visitor to contaminated surface soil
and air and the exposure of trespassers to contaminated surface
soil, the waste pile, on-site shingle piles 1, 2, and 3, and the
sediments in the site water bodies. Since shingle pile 2 contained
the highest contaminant concentrations, this data was used to
represent all three on-site shingle piles. Future potential
exposure pathways include the exposure of a child resident to
surtace and subsurface soils and the exposure of a future adult
worker to subsurface soil. For the subsurface pathway, the
assumption was made that the subsurface soil was excavated during
16
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building construction and was available for the direct contact
exposure pathway. The exposure routes evaluated are ingestion and
dermal absorption resulting from direct contact with the site
contaminated media and inhalation of airborne contaminants. The
exposure assumptions are contained in Table 3.
6.1.3
Toxicitv Assessment
Slope factors (SFs) have been developed by EPA' s Carcinogenic
Assessment Group for estimating lifetime cancer risks associated
with exposure to potentially carcinogenic contaminants of concern.
SFs, which are expressed in units of (mg/kg-day)-l, 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
results of human epidemiological studies or chronic animal
bioassays to which animal-to-human extrapolation and uncertainty
factors have been applied. The SFs for the carcinogenic
contaminants of concern are contained in Table 4.
As an interim procedure, until more definitive Agency guidance is
established, Region IV has adopted a toxicity equivalency factor
(TEF) methodology for evaluating carcinogenic PAHs. This
methodology is based on each compound's relative potency to the
potency of benzo(a)pyrene. The TEFs for the carcinogenic PAHs are
contained in Table 4.
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure to
contaminants of concern exhibiting noncarcinogenic effects. RfDs,
which are expressed in units of mg/kg-day, are estimates of
lifetime daily exposure levels for humans, including sensitive
individuals. Estimated intakes of contaminants of concern from
environmental media (e.g. the amount of a contaminant 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 (to account
for the use of animal data to predict effects on humans). The RfDs
for the noncarcinogenic contaminants of concern are contained in
Table 4.
6.1.4
Risk ~Aracterization
For carcinogens, risks are estimated as the incremental probability
of an individual developing cancer over a lifetime as a result of
exposure to the carcinogen. Excess lifetime cancer risk is
calculated from the following equation:
Risk = CDI x SF
17
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Table 2
Exposure Point Concentrations
Chemical
Concentration
Soil (Surface and Subsurface) (ma/ka)
Surface
Subsurface
Arsenic
Chlordane
Ethion
Lead
Carcinogenic
PCBs
PAHs4
13
6.2
5
704
16.7
18
7
NA
NA
809
6
NA
Sediment (ma/ka)
North Drainage
Ditch
Removal Pond
No.2
Carcinogenic PAHs4
4.8
13.2
Removal Pond
No.5
Removal Pond
No.6
Arsenic
Carcinogenic PAHs.
Zinc
NA
14.3
NA
59
NA
490
Hotst)ot (ma/ka)
Chlordane
Carcinogenic PAHs.
Shingle Pile 2
NA
626
Waste Pile
24.3
36.4
Air (ug/cubic meter)
Chlordane
0.89
4
Indicates that these chemicals were carried through the risk
assessment but did not produce risks at levels of concern.
The carcinogenic PAH data consists of the data for
benzo(a)anthracene, chrysene, benzo(a)pyrene,
dibenzo(a, h) anthracene, benzo(b and/or k)fluoranthene and
indeno(l,2,3-c,d)pyrene. The concentration accounts for the
relative.potency of benzo(a)pyrene.
NA
18
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Table 3
Exposure Assumptions for Soil,
Sediment, and Air Pathways
Parameter
Ingestion Rate (mg/event)
Exposure Frequency (dy/yr)
Exposure Duration (yr)
Body Weight (kg)
Exposed Skin Area (cm2)
Adherence Factor (mg/cm2)
Absorption Rate (metals) (%)
Absorption Rate (organics) (%)
Inhalation Rate (m3/hr)
Exposure Time (hr/dy)
Parameter
Ingestion Rate (mg/event)
Exposure Frequency (dy/yr)
Exposure Duration (yr)
Body Weight (kg)
Exposed Skin Area ( cm2 )
Adherence Factor (mg/cm2)
Absorption Rate (metals) (%)
Absorption Rate (organics) (%)
Inhalation Rate (m3/hr)
Exposure Time (hr/dy)
..
Adult Worker
Trespasser
50
250
30
70
2300
0.2
0.1
1
0.83
8
100
80"
9
35
2500
0.2
0.1
1
0.29
4
Child Visitor
Child Resident
200
100
5
16
2300
0.2
0.1
1
0.29
8
200
280
5
16
2500
0.2
0.1
1
0.29
24
The expo8ure frequency for trespasser exposure to sediments is
30 dy/yr.
19
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Table 4
Toxicity Values for Contaminants of Concern
Carcinoaenic Slope Factors
Slope Factor Weight of
Chemical (mg/kg-dy) -1 Evidence Source
Arsenic 1.8 A IRIS
Chlordane 1.3 B2 IRIS
Benzo ( a ) pyrene" 5.8 B2 ECAO
PCBs 7.7 B2 IRIS
Reference Doses (RfDs)
Chemical
Reference Dose
(mg/kg-dy)
3E-04
6E-05
Critical
Effect
Source
Arsenic
Chlordane
Ethion
5E-04
Keratosis
Liver
Hypertrophy
Plasma
Cholinesterase
Inhibition
IRIS
IRIS
IRIS
"
The toxicity equivalency factors (TEFs) used to evaluate the
carcinogenic PAHs are:
Compound
TEF
0.1
1.0
0.1
0.1
0.01
1.0
0.1
Benzo (a) anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
ChryS8118
Dibenao(a,h) anthracene
Indeno(1,2,3-c,d)pyrene
IRIS = Integrated Risk Management System
ECAO = Environmental Criteria and Assessment Office
20
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CDI
=
a unitless probability of an individual
developing cancer
chronic daily intake averaged over 70 years
(mg/kg-day)
slope-factor, expressed as (mg/kg-day) -1.
where:
risk =
SF
=
These risks are probabilities that are generally expressed in
scientific notation (e.g. lxlO-6). An excess lifetime cancer risk
of lx10-6 indicates that an individual has an additional 1 in
1,000,000 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. A summary of the potential current
and future carcinogenic risks are contained in Tables 5 and 6.
The potential for noncarcinogenic effects is evaluated by comparing
an exposure level over a specified time period (e.g. lifetime) with
a reference dose derived for a similar exposure period. The ratio
of exposure to toxicity is called a hazard quotient (HQ). The
hazard index (HI) can be generated by adding the HQs for all
contaminants of concern that affect the same target organ (e.g.
liver) within a medium or across all media to which a given
population may reasonably be exposed. The HQ is calculated below:
Noncancer HQ = CDI/RfD
where:
CDI
RfD
=
chronic daily intake
reference dose
=
CD! and RfD are expressed in the same units (mg/kg-day) and
represent the same exposure period (i.e., chronic, subchronic, or
short-term) .
A summary of the potential current and future HQs is presented in
Table 7. This table contains risk information for chemicals and/or
pathways which have individual or cumulative HQs which exceed 0.1.
Soil and Sediment Risks
For current use, risk levels from carcinogenic contaminants of
concern in soil, sediment and air do not exceed the acceptable risk
range. The highest current risk level, 4x10-5 was for an adult on-
site worker. The HIs for non-cancer risks did not exceed 1 for any
current use exposure pathways. Sediment exposure did not exceed
either the risk range or an HI of 1. The risk to a potential
trespasser ezposed to shingle pile 2 (1x10-4) is at the upper end
of the acceptable risk range. Exposure to airborne pesticides are
within the protective range for both adult workers and child
visitors.
For future use scenarios, the highest cancer risk (9x10-5) is
associated with a child resident having direct contact with the
site soils. Exposure to subsurface soils brought to the surface by
21
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Table 5
SI'I_Ary of Current Site Carcinogenic Risks&
Surface Soil - Direct Contact
Young Child Teenage
Chemical Adult Worker Visitor Trespasser
Arsenic 2E-6 2E-6 3E-7
Chlordane lE-6 lE-6 2E-7
PCBs lE-6 2E-6 3E-7
PAHs 3E-S 3E-S SE-6
Cumulative 4E-S 3E-S 6E-6
Sediment - Direct Contact (Trespasser)
North Drainage
Chemical Ditch Pond 2 Pond 5 Pond 6
Arsenic NA NA NA 3E-6
PARs lE-6 3E-6 3E-6 NA
Hotspot - Direct Contact (Trespasser)
Chemical
Shingle Pile 2
NA
lE-4
Waste Pile
Chlordane
PAHs
lE-6
lE-6
Air - Inhalation
Adult Worker
Young Child
Visitor
Teenage
Trespasser
Chemical
Chlordane
2E-S
4E-6
7E-7
&
A cumulative receptor risk can be obtained by summing the risks
obtained from each exposure route for an individual receptor.
Indicates that chemicals were carried through the risk
assessment but did not produce risks at levels of concern.
NA
22
-------
Chemical
Arsenic
Chlordane
PCBs
PAHs
Cumulative
Chemical
Arsenic
PAHs
Cumulative
Table 6
SJ~~ry of Future Site Carcinogenic Risks
Surface Soil - Direct Contact
Child Resident
SE-6
3E-6
4E-6
8E-S
9E-S
Subsurface Soil - Direct Contact
Child Resident
2E-6
2E-S
2E-S
Adult Worker
3E-7
3E-6
4E-6
23
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Table 7
S11mm~ry of Hazard Quotients.
Chemical
Current Scenarios (Direct Contact)
Child Visitor
Cumulative
6E-2
2E-l
SE-2
3E-l
Arsenic
Chlordane
Ethion
Chemical
Teenage Trespasser
Pond 6 Waste Pile
Cumulative
3E-2 NA
NA lE-l
2E-2 NA
4E-2 NA
lE-l lE-l
Arsenic
Chlordane
Ethion
Zinc
Future Scenarios (Direct Contact)
Child Resident Child Resident
Chemical (Surface) (Subsurface)
Arsenic 2E-l 4E-2
Chlordane 6E-l lE-l
Ethion lE-l lE-2
Leadb
Cumulative lE+O 2E-l
b
The hazard quotients are summarized in this table for which the
cumulative hazard index is equal to or greater than 0.1.
The lead biokinetic model indicates that the blood lead level
will exceed the Agency benchmark of 10 ug/dl, in 24% of the
potential future residential population exposed to surface soil
and 37% of the future population potentially exposed to
subsurface soil.
.
NA
Notation indicates that chemicals were carried through the risk
assessment but did not produce risks at levels of concern.
24
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excavation and construction activities would not result in risks
for future residents or workers exceeding the target risk range.
Although future noncancer risks (HQs) for individual pathways do
not exceed 1.0, the cumulative noncancer risk (HI) is 1.0 for a
future residential exposure to surface soil, indicating that a
future child resident may experience non-carcinogenic toxic effects
as a result of exposure to site surface soils.
The lead uptake/biokinetic model was used to estimate the effect on
the blood lead level of a future young child (0-5 years) resident
resul ting from exposure to the surface and subsurface .soil. mean
lead concentration in contaminated portions of the site. The model
predicts that the blood lead level will exceed the Agency benchmark
level of 10 ug/dl in 24% of the child residential population
exposed to surface soil and in 37% of the child residential
population exposed to subsurface soil.
To address the risks presented above, EPA calculated potential
Remedial Action Objectives (RAOs) which result in risks of 10-4,
10-5, and 10-6, and an HI of 1.0. RAOs were calculated for the
current on-site worker and the future child resident scenarios.
Based on the current industrial zoning of the Bay Drums site area
and the unlikely scenario of the site being rezoned residential,
RAOs relating to cancer risk of 10-4 and a noncancer HI equal to 1.0
for a current worker were used to identify the risk-based
performance standards for soils and sediments at the site.
Groundwater Risks
The area-wide groundwater risk assessment did not address current
exposure since on-site groundwater is not currently being used.
However, the risks associated with possible future exposure for
workers or residents exceeds the risk range for both the shallow
aquifer and the deeper Floridan Aquifer, which is the current
source of municipal water supplies in the area. For this reason,
actual or threatened releases of hazardous substances from the site
soils and sediments into the groundwater, if not addressed by
implementing the response action selected in this ROD, may present
an imminent and substantial endangerment to the public health,
welfare, or the environment. The endangerment is a result of the
potential for further degradation of the area-wide groundwater via
leaching of contaminants from the contaminated site soils and
sediments.
To address this concern, RAOs for soils and sediments that are
protective of groundwater were developed for those contaminants at
the site which were present in both soil and groundwater. Straight
partitioning and the SUMMERS model were used to develop
groundwater protection action levels for five contaminants,
including ethyl benzene, toluene, xylene, naphthalene, and lead.
Of these constituents, lead was the only one which exceeded its
groundwater protection remedial action objective of 284 ppm.
25
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6.1.5
Uncertainties in Risk Assessment
The evaluation of risks at a site depends on the development of a
number of site-specific assumptions and the use of experimentally-
derived chemical toxicity information. These assumptions and
experimental data introduce a small degree of uncertainty into site
risk assessments. The most significant uncertainty in this
assessment is probably associated with the toxicity assessment for
carcinogenic PAHs and arsenic. Historically, the Agency has
evaluated the carcinogenic PAHs by summing and estimating the risk
with the carcinogenic slope factor for benzo(a)pyrene (BaP)., The
Agency recognizes that this could be an overly conservative
approach and is currently evaluating the use of relative potency
factors for assessing the carcinogenic potency of these compounds
relative to BaP. Region IV has adopted these potency factors
because it is believed that this method gives a closer
approximation of the risk associated with this class of chemicals.
The determination of the arsenic slope factor currently being used
was reassessed recently by the Risk Assessment Forum and has been
extensively peer reviewed. Based on this evaluation, the slope
factor could be modified downward by as much as an order of
magnitude. This means that the carcinogenic risks associated with
presented in the Bay Drums risk assessment could be overestimated.
6.2
Environmental Risks
The environmental risks at this site were addressed in a separate
study (Area-wide Wetlands Impact Study). This study evaluated the
ecological status of the wetlands associated with the Bay Drum,
Peak Oil and Reeves Southeastern sites. The results of this study
are contained in the Areawide Wetlands Impact Study Report. The
wetlands associated with these three sites will be addressed in a
separate operable unit ROD.
7.0
DESCRIPTION OP ALTERNATIVES
A Feasibility Study (FS) was conducted to develop and evaluate
alternatives for addressing soil and sediment contamination at the
Bay Drums site. In the FS, remedial alternatives were assembled
from applicable remedial activities known as process options.
These alternatives were initially evaluated for effectiveness,
implementability, and cost. Based on this screening, five
alternativee were retained for evaluation against the nine criteria
prescribed by the NCP. Included among the remedial alternatives is
the no-action alternative, which is required by the NCP to serve as
a basis for comparison for the other alternatives.
The alternatives considered for addressing soil and sediment
contamination at the Bay Drums site include the following:
Alternative 1
Alternative 2
No Action
Containment
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Alternative 3
Alternative 4
In-Situ Stabilization/Solidification
Ex-Situ Stabilization/Solidification and
On-Site Disposal
Ex-Situ Stabilization/Solidification and
Off-Site Disposal
Alternative 5
A number of process options are common to all alternatives except
Alternative 1. These activities are described below:
o
Conduct groundwater monitoring on a periodic basis in
conjunction with groundwater remediation to assess _rem~dial
action performance and contaminant migration.
o
Conduct perimeter and work zone air monitoring during remedial
action activities to ensure worker safety and prevent off-site
emissions.
o
Demolish, dismantle, and decontaminate all on-site structures
and dispose in an appropriately permitted off-site landfill.
Dispose of an estimated 5,000 cubic yards of non-hazardous
debris in an appropriately permitted off-site landfill.
o
o
Dispose of approximately 27,000 cubic yards of shingle debris
(known as the On-site Shingles) in accordance with all
applicable Federal, State, and local requirements.
o
Dredge approximately 1,500 cubic yards of sediments from the
pond areas and north drainage ditch and consolidate these
sediments onto another contaminated area of the site.
o
Dewater and backfill the pond areas with clean fill material.
Construct drainage ditches as needed to prevent ponding of
water on the site.
o
o
Place 4 inches of topsoil over remaining portions of the site
and revegetate the site with native grasses to prevent
erosion.
7.1
A1ternative 1 - Ho Action
In the No Action alternative, no remedial action would be taken at
the Bay Drums site. While EPA guidance allows the inclusion of
environmental monitoring in this alternative, no measures may be
taken to reduce the potential for exposure through the use of
institutional controls, containment, treatment, or removal of
contaminated soils or sediments. As required by SARA, the no
action alternative provides a baseline for comparison with other
alternatives that provide a greater level of response.
The process options which comprise the No Action alternative
include the following:
27
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o
Conduct groundwater monitoring on a periodic basis to assess
contaminant migration.
For cost estimating purposes, groundwater monitoring is expected to
occur on a semi-annual basis for a period of 30 years.
The primary applicable or relevant and appropriate requirement
(ARAR) for this alternative is the treatment technique action level
for lead in groundwater from the Safe Drinking Water Act (SDWA).
Modelling conducted by EPA indicates that if no action is taken to
treat or contain contaminated site soils, lead may continue to
leach into the groundwater above the action level. For this
reason, Alternative 1 does not meet ARARs.
There are no capital costs associated with the implementation of
Alternative 1. However, the annual cost of groundwater sampling
and analysis is estimated to be $41,000, resulting in a total net
present worth cost over 30 years of approximately $640,000.
7.2
Alternative 2 - Containment
The Containment alternative would isolate approximately 16,500
cubic yards of contaminated soils and sediments, eliminating the
potential for area residents and workers to be exposed to site
contaminants. In addition to the elements common to all
alternatives described in Section 7.0, Alternative 2 incorporates
the following additional components:
o
Erect an eight-foot security fence with appropriately spaced
warning signs to prevent entry.
Record deed notices with Hillsborough County advising that
hazardous constituents are disposed on the site.
o
o
Install a slurry wall around the site which would be keyed
into the clay confining unit beneath the site.
Construct a multimedia cap (as prescribed in RCRA Subtitle C)
over the consolidated waste and key the cap into the slurry
wall.
o
During installation of the slurry wall, some excess slurry may be
produced. Although these residuals are not expected to be
contaminated, they can be placed on a contaminated portion of the
site (similar to the sediments) and contained beneath the
multimedia cap.
This alternative may not meet the SDWA treatment technique action
level for lead in groundwater, since elevated lead levels in soils
remaining on-site may continue to leach into the groundwater. Any
construction activities which disturb contaminated soils would be
designed to meet the National Ambient Air Quality Standards (NAAQS)
28
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of the Clean Air Act and Florida Ambient Air Quality Standards.
Finally, although the contaminants at the site are not considered
to be RCRA hazardous wastes, the RCRA Subtitle C regulations would
provide minimum technology requirements for the design of the
multimedia cap. In general, Alternative 2 can be designed to meet
all ARARs, although monitoring must be conducted to verify that
lead contamination does not continue to leach into the groundwater
above the SDWA action level.
The annual operation and maintenance costs associated with
Alternative 2 are estimated to be about $20,000, with mQnitQring
continuing for a period of 30 years. The net present worth cost of
this alternative is estimated to be $2,940,000.
7.3
Alternative 3 - In-Situ Stabilization/Solidification
~ternative 3 involves the in-place (in-situ) stabilization/
solidification of approximately 16,500 cubic yards of lead and
pesticide-contaminated soils and sediments. In addition to the
elements common to all alternatives, the process options included
in this remedial alternative are listed below:
o
Erect an eight-foot security fence with appropriately spaced
warning signs to prevent entry.
o
Record deed notices with Hillsborough County advising that
hazardous constituents are disposed on the site.
o
Treat contaminated soils and sediments in place using a cement
or pozzolan-based in-situ stabilization/solidification
process.
o
Construct a low permeability clay cap over stabilized areas to
prevent percolation of precipitation through the stabilized
material.
The in-situ stabilization/solidification process would result in
treated materials remaining within the saturated zone. No
hazardous residuals are anticipated to result from implementation
of this alternative. Any excess stabilization and solidification
agents may be disposed on-site beneath the low permeability cap
along with the treated materials. .
By stabilization and solidification of contaminated materials, this
alternative can be designed to prevent leaching of contamination
above the SDWA treatment technique action level for lead in
groundwater. Any construction activities which disturb
contaminated soils would be designed to meet the NAAOS and Florida
Ambient Air Quality Standards. Additionally, real-time air
monitoring would be conducted in work zones and around the site
perimeter to ensure that these standards are met. Therefore,
Alternative 3 can be designed to meet all ARARs.
29
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The annual operation and maintenance costs associated with
Alternative 3 are estimated to be about $20,000, with monitoring
assumed to continue for a period of 30 years. The net present
worth cost of this alternative is estimated to be $3,290,000.
7.4
Alternative 4 - Ex-Situ Stabilization/Solidification and On-
Site DisDOsal
This alternative involves the excavation of contaminated materials,
ex-situ stabilization/solidification, and disposal of treated
material on-site above the water table. A low permeability clay
cap would then be constructed to reduce rainwater infiltration
through the waste. In addition to the elements common to all
alternatives, Alternative 4 includes the following components:
o
o
o
o
o
o
Erect an eight-foot security fence with appropriately spaced
warning signs to prevent entry.
Record deed notices with Hillsborough County advising that
hazardous constituents are disposed on the site.
Excavate approximately 15,000 cubic yards of contaminated
soils.
Treat contaminated soils and sediments on-site in a cement or
pozzolan-basedex-situ stabilization/solidification treatment
process.
Dispose of treated soils and sediments
excavated areas above the water table.
in
on-site
the
Construct a low permeability clay cap over these materials to
prevent percolation of precipitation through the stabilized
material.
No hazardous residuals are anticipated to result from
implementation of this alternative. Any excess stabilization and
solidification agents may be disposed on-site beneath the low
permeability cap along with the treated materials.
Similar to Alternative 3, by chemical stabilization treatment and
physical solidification of contaminated materials, this alternative
can be designed to prevent leaching of contamination above the SDWA
treatment technique action level for lead in groundwater.
Construction. activities which disturb contaminated soils would be
designed to meet the NAAQS and Florida Ambient Air Quality
Standards, and work zone and perimeter air monitoring would be
conducted to ensure worker and public safety. Therefore,
Alternative 4 can be designed to meet all ARARs.
The annual operation and maintenance costs associated with
Alternative 4 are estimated to be about $20,000, with monitoring
30
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assumed to continue for a period of 30 years. The net present
worth cost of this alternative is estimated to be $2,680,000.
7.5
Alternative 5 - Ex-Situ Stabilization/Solidification and Off-
Site DisDOsal
Alternative 5 involves many of the same elements as Alternative 4,
with the exception that treated materials would be disposed in an
off-site landfill rather than on-site. In addition to the elements
common to all alternatives, Alternative 5 includes the following
components:
o
Excavate approximately 15,000 cubic yards of contaminated
soils.
o
Treat approximately 16,500 cubic yards of contaminated soils
and sediments in an on-site cement or pozzolan-based ex-situ
stabilization/solidification treatment process.
Backfill excavated areas with clean fill.
o
Dispose of treated soils and sediment in an EPA approved off-
site disposal facility.
No hazardous residuals are anticipated to result from
implementation of this alternative. Any excess stabilization and
solidification agents may either be disposed in on-site excavations
or off-site with the stabilized materials.
o
This alternative prevents leaching of contaminants into the
groundwater above health-based standards by stabilization and
solidification of contaminated materials and disposal in an off-
site landfill. Construction activities which disturb contaminated
soils would be designed to meet the NAAQS and Florida Ambient Air
Quality Standards, and work zone and perimeter air monitoring would
be conducted to ensure worker and public safety. No fencing or
institution controls would be necessary since all contamination
which exceeds health-based levels would be taken to an off-site
landfill. Finally, all off-site disposal activities would comply
with EPA's Off-Site Policy. In summary, Alternative 5 can be
designed to meet all ARARs.
The annual operation and maintenance costs associated with
Alternative 5 are estimated to be about $20,000, with monitoring
assumed to continue for only 5 years. The net present worth cost
of this alternative is estimated to be $3,210,000.
8.0
COMPARATIVE AHALYSIS OP SOURCE CONTROL ALTERKATIVES
In this section, the performance of each alternative relative to
the other alternatives will be evaluated for each of the nine
criteria identified in the March 1990 version of the NCP (40 CFR
Part 300.430). The criteria are listed in the NCP and discussed
31
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further in EPA's guidance for conducting Remedial Investigations
and Feasibility Studies. The nine criteria are segregated into
three categories. Threshold Criteria are those which dictate the
minimum standards with which a remedial alternative must comply.
Primary Balancing Criteria include those which are used to evaluate
the effectiveness of the remedial alternatives. Finally, Modifying
Criteria are those which may be used in distinguishing between
equally protective alternatives. The breakdown of the nine
criteria into these categories is shown below:
Threshold Criteria
o
o
Overall Protection of Human Health and the Environment
Compliance with ARARs
primary Balancing Criteria
o
o
o
o
o
Long-Term Effectiveness and Permanence
Reduction of Toxicity, Mobility or Volume
Short-term Effectiveness
Implementability
Costs
through Treatment
Hodifying Criteria
o
o
State Acceptance
Community Acceptance
A comparison of the remedial alternatives with respect to each of
these criteria and each other is presented in the following
sections. Those al ternati ves . which fail to meet the threshold
criteria of overall protection of human health and the environment
and compliance with ARARs will be eliminated from further analysis.
Table 8 provides a tabular summary of this analysis.
8.1
Overall Protection of Human Health and the Environment
This criterion assesses whether alternatives adequately protect
human health and the environment and to what degree an alternative
would eliminate, reduce, or control the risks to human health and
the environment associated with the site, through treatment,
engineering, or institutional controls. It is an overall
assessment of protection that encompasses an assessment of other
criteria such as long-term effectiveness and permanence, short-term
effectivene88, and compliance with ARARs.
All remedial alternatives except No Action are considered
protective of human health and the environment. The No Action
alternative allows constituents to remain on-site above health-
based levels, and potential impacts to groundwater from these
materials are not addressed. Since the No Action alternative does
not eliminate, reduce, or control any of the exposure pathways, it
is therefore not protective of human health or the environment and
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Alternative 1
No Action
Table 8
Comparative Analysis of Alternatives
Bay Drums Superfund Site
Alternative 2
Containment
Alternative 3
In-Situ sls
Alternative 4
Ex-Situ sls &
On-Site Disposal
Alternative 5
Ex-Situ sls &
Off-Site Disposal
Overa.ll
Protection
Compliance with
ARAR8
Long-term
Effectiveness
Reduction of
Toxicity,
Mobility, S
Volume (THY)
Short-term
Effectiveness
~lementability
Costs (Ret
Present Worth)
Rot protective.
Protects human
health. May
allow degradation
of on-site
ground-water.
Can be designed
to comply with
ARARs.
Some residual
risk. Maintenance
of RCRA cap and
groundwater
monitoring
required.
No reduction of
THY.
Dust generated by
construction
activities may
result in
temporary short-
term impacts.
Installation of
slurry wall in
sandy soils may
result in caving.
Deed restrictions
required.
$2,940,000
Protects human
health and the
environment.
Can be designed
to comply with
ARARs .
Low residual
risk. Maintenance
of clay cap and
groundwater
monitoring
necessary.
Reduction
mobility.
reduction
toxicity;
increase.
of
No
of
volume
Protects human
health and the
environment.
Can be designed
to comply with
AMRs .
Low residual
risk. Maintenance
of clay cap and
groundwater
monitoring
necessary.
Reduction
mobility.
reduction
toxicity;
increase.
of
No
of
volume
Protect. human
health and the
environment.
Can be designed
to comply with
ARARs.
Minimal residual
risk at the site,
but risk trans-
ferred to another
location. Long-
term maintenance
is minimal.
Reduction
mobility.
reduction
toxicity;
increase.
of
No
of
volume
Degree of dust
generation
depends on in-
situ sls method
selected.
Presence of
subsurface
obstructions
inhibits mixing
efficiency. Deed
restrictions
required.
$3,290,000
Heavy earth
moving equipment
expected to cause
short-term safety
hazards and dust
generation.
No implementation
issues expected.
Deed restrictions
required. '
$2,680,000
Heavy earth
moving equipment
expected to cause
short-term safety
hazards and dust
generation.
Administrative
issues such as
manifesting,
permits, and
public opposition
to off-site dis-
posal expected.
$3,210,000
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will not be considered further in this analysis as an option for
addressing soil contamination.
Although Alternative 2 may allow the leaching of contaminants above
health-based criteria to continue, the slurry wall around the site
perimeter would restrict off-site migration of contaminants,
thereby reducing the potential for human exposure to site-related
constituents.
Alternatives 3, 4, and 5 would reduce the risk from contaminated
soils by immobilizing constituents through stabilization and
solidification. Alternatives 3 and 4 would also provide additional
protection by containing the treated materials on-site. Finally,
Alternative 5 would provide the greatest degree of protection
through the secure disposal of treated materials in an off-site
landfill.
8.2
Comnliance with ARABs
This criterion considers whether a remedial alternative meets all
Federal and State ARARs. Unless a waiver is justified, the
selected remedy must comply with all chemical-specific, location-
specific, or action-specific ARARs.All remaining alternatives can
be designed to meet ARARs. Although Alternative 2 allows untreated
contaminated media to remain on-site, this alternative prevents
degradation of off-site groundwater by containing contaminated
groundwater within a slurry wall. Although RCRA is not an ARAR,
the multimedia cap will be designed to meet RCRA Subtitle C minimum
technology requirements.
8.3
Lona-Term Effectiveness and Permanence
This criterion assesses whether a remedial alternative would carry
a potential, continual risk to human health and the environment
after the remedial action is completed. An evaluation is made as
to the magnitude of the residual risk present after the completion
of the remedial actions as well as the adequacy and reliability of
controls that could be implemented to monitor and manage the
residual risk remaining.
Alternative 5 is considered to provide the greatest degree of long-
term effectiveness since the residual risk remaining at the site
after implementation would be minimal. However, residual risks
associated with the treated materials would be transferred to
another location by off-site transport and disposal. Monitoring of
the effectiveness of this alternative is likely to be limited to an
initialS-year period, after which the site may be considered for
delisting from the National Priorities List (NPL) with no further
monitoring.
All remaining alternatives will involve increasing degrees of
residual risk and will require varying amounts of monitoring and
maintenance of site conditions for some period of time. The
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residual risks associated with Alternatives 3 and 4 will be fairly
small, since the contaminants will be immobilized through treatment
and isolated through capping. These alternatives will require
periodic groundwater monitoring and an initial Five Year Review to
monitor the effectiveness of the remedial action, after which EPA
may determine that no additional monitoring is necessary.
Alternative 2 will involve a higher degree of residual risk, since
no treatment is done to reduce texicity, mobility, or volume. This
alternative relies heavily on the continued maintenance of the
mul timedia cap, enforcement of institutional controls, anq per.iodic
groundwater monitoring to insure the effectiveness of the
engineered containment measures.
8.4
Reduction of Toxicitv. Mobility. or Volume throuah Treatment
This criterion assesses the degree to which a remedial alternative,
by utilizing treatment technologies, would permanently and
significantly reduce the toxicity, mobility, or volume of hazardous
substances at the site. The assessment focuses on the magnitude,
significance and irreversibility of treatment.
Alternative 5 provides the greatest degree of mobility reduction by
stabilization/solidification of the waste and disposal in a secure
off-site facility. The two on-site treatment alternatives,
Alternatives 3 and 4, will reduce constituent mobility by fixing
contaminants in a solidified matrix. Alternative 2 is not
considered to reduce mobility since site contaminants are merely
contained through the use of engineered controls.
None of the alternatives provides any reduction in the toxicity or
volume of site constituents. Alternatives 3, 4, and 5 are expected
to result in an increase in the total volume of contaminated media
because of the addition of stabilization and solidification agents.
However, no increase in the volume of constituents occurs.
8.5
Short-Term Effectiveness
This criterion assesses the degree to which human health and the
environment would be impacted during the construction and
implementation of the remedial al ternati ve . The protection of
workers, the community, and the surrounding environment as well as
the time to achieve the remedial response objectives are considered
in making this assessment.
Alternative 2 will have few short-term impacts. The construction
activities associated with Alternative 2 will involve minimal
disturbances of contaminated soils, although the dredging of
contaminated sediments may require the use of dust and vapor
controls. Depending upon the method selected for in place
stabilization, Alternative 3 may result in significant dust
generation during the mixing process, requiring the use of air
'monitoring and dust suppression measures.
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Both ex-situ treatment alternatives (Alternatives 4 and 5) will
involve the use of numerous pieces of heavy construction equipment
and significant disturbances of contaminated soils. Therefore,
careful construction staging will be necessary to provide a safe
working environment. Additionally, air monitoring and dust
suppression will need to be used to minimize impacts from dust
generated during remedial action activities.
8.6
LmDlementabilitv
This criterion assesses the technical and administrative
feasibility of implementing a remedial alternative -and' the
availability of services and materials required during
implementation.
While each of the alternatives will involve some technical and/or
administrative implementation issues, Alternative 4 appears to
involve the least. Alternatives 2, 3, and 4 will require obtaining
agreements from site owners to file deed notices to restrict site
access and development.
Alternative 5, which involves the off-site transportation and
disposal of stabilized materials, has a number of administrative
issues which may arise during implementation. In recent years,
communities in which industrial or hazardous waste landfills are
located have often resisted the importation of Superfund wastes
from other communities or states. This has resulted in delays to
the projects and increased costs. Additionally, extensive
administrative effort must be expended to secure the appropriate
transportation permits, waste codes, and manifests before taking
the wastes off-site.
Finally, Alternatives 2 and 3 are the only alternatives which are
expected to encounter technical implementability issues. For
Alternative 2, the installation of the slurry wall in the sandy
soils at the Bay Drums site may present unique difficulties in
keeping the trench excavation open. For Alternative 3, underground
obstructions may be encountered in performing the in-situ mixing
activities which could compromise the mixing efficiency, resulting
in a low-strength monolith or pockets of unstabilized soils. The
remaining alternatives involve straightforward construction
technologies which are not expected to present any unique technical
difficultie8.
8.7
Cost
This criterion assesses the capital costs, operation and
maintenance costs, and total present worth analysis associated with
implementing a remedial alternative. The capital costs are divided
into direct costs and indirect costs. Direct capital costs include
construction costs, equipment costs, and site development costs.
Indirect capital costs include engineering expenses and contingency
allowances. Operation and maintenance (O&M) costs are post-
36
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construction costs necessary to ensure the continued effectiveness
of a remedial action.
In accordance with EPA guidance, the estimated costs presented in
the FS are expected to provide an accuracy of +50 to -30 percent
(USEPA 1988). EPA's detailed cost calculations for each
alternative are provided in Appendix A.
The least expensive alternative is Alternative 4 at $2.68 million,
and Alternative 2 is the medium-priced alternative at $2.94
million. The remaining two alternatives, Alternatives 3 and 5,
cost $3.29 million and $3.21 million, respectively, which' is a
price variation of less than 3 percent. The alternatives evaluated
represent a difference of about 23 percent between the lowest and
highest priced alternatives, providing the Agency with a range of
reasonably priced alternatives from which to select the preferred
remedial action for the site.
8.8
State AcceDtance
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 Regulation (FDER), has been the support agency during
the Remedial Investigation and Feasibility Study process for the
Bay Drums site. In accordance with 40 CFR 300.430, as the support
agency, FDER has provided input during this process. Based upon
comments received from FDER, it is expected that concurrence will
be forthcoming; however, a formal letter of concurrence has not yet
been received.
8.9
Community AcceDtance
This criterion assesses the issues and concerns the public may have
regarding each of the remedial alternatives. In order to solicit
the public's input, EPA issued a Proposed Plan fact sheet in August
1992 and held a comment period from August 13 to September 12, 1992
in order to obtain the community's input. Additionally, EPA
conducted a joint public meeting for the Bay Drums, Peak Oil, and
Reeves sites on August 18, 1992 in which EPA representatives
presented the results of the RIfFS and discussed EPA's preferred
alternative for the three sites. Only a handful of residents from
the surrounding community attended the meeting.
EPA's response to the comments that were received at the public
meeting and during the comment period have been summarized in the
Responsiveness Summary in Section III of this ROD. While few
concerns were expressed by the local community about any of the
alternatives considered for the Bay Drums site, EPA is concerned
that the communities surrounding the off-site disposal facilities
37
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selected in conjunction with the implementation of Alternative 5
might resist the importation of Superfund wastes into their
communities. This is not a concern for the remaining al terna ti ves ,
which involve primarily on-site activities.
9.0
SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the
detailed analysis of remedial alternatives using the nine criteria,
and public comments, EPA has selected Alternative 4 as the most
appropriate remedial alternative for addressing source
contamination at the Bay Drums site. The specific elemerits which
comprise the selected remedy are discussed below.
Treatment Components
Approximately 16,500 cubic yards of contaminated soils and
sediments exceeding performance standards shall be treated on-site
using an ex-situ stabilization/solidification process. The
stabilization/solidification process used for treating contaminated
soils and sediments shall utilize a combination of Portland cement
and fly ash or other pozzolans to produce a relatively high-
strength, low permeability monolith. Treatability studies shall be
conducted during Remedial Design to determine what impacts the
presence of organics compounds and shingle fragments may have on
the ability of the stabilization/solidification process to meet
performance standards.
Those areas of the site which exceed performance standards based on
the results of the RI are shown in Figure 6. Excavation of
additional areas may be necessary based on the results of
confirmational sampling conducted during the remedial design and
remedial action phases. Soils shall be excavated using
conventional construction equipment such as backhoes, scrapers, and
dozers, and soil excavations shall be designed to prevent caving.
Surface pond and ditch sediments shall either be removed with a
backhoe or dredged using physical means such as a dragline.
Dewatering of surface ponds may be necessary prior to removal of
sediments. Excavated areas and surface ponds shall be backfilled
with clean imported fill.
Containment and DisDOsal Components
Following stabilization/solidification, treated materials shall be
disposed on-site above the water table. This shall be accomplished
through placement of the stabilized materials in the former process
areas from which they were excavated. Some of the treated material
may be disposed below natural ground surface, provided that these
materials remain above the water table during all times of the
year. However, partial backfilling of excavated areas may be
necessary to ensure that waste is not disposed in the saturated
zone.
38
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A low permeability surface cap (illustrated in Figure 7) shall be
constructed over treated materials. This cap shall be constructed
of a low permeability soil layer (approximately 2 ft. thick) with
a minimum permeability of 10-7 em/see and a 1 ft. topsoil layer to
sustain vegetation. The area designated for treated soil disposal
and capping is shown in Figure 8. Addi tionally, the remaining
portions of the site shall be covered with 1 foot of topsoil cover
to prevent runoff potentially affected by residual contamination
below performance standards from impacting wetlands near the site.
Finally, the entire site shall be seeded with native grasses to
prevent erosion of the cap and soil cover.
Prior to the excavation of contaminated soils, all site structures
must be demolished or dismantled and decontaminated. Demolition
debris shall be disposed in a non-hazardous industrial waste
landfill, provided that sampling is conducted to demonstrate that
the material is not hazardous. If sampling indicates that the
materials are hazardous and decontamination is not possible, then
the material must be disposed in a hazardous waste landfill. Other
non-hazardous debris present at the site which is associated with
past operations shall be disposed off-site. EPA has not quantified
the amount of material requiring disposal, but for cost estimating
purposes, a volume of 5,000 cubic yards of non-hazardous debris was
assumed. Additionally, an estimated 27,000 cubic yards of shingle
debris (known as the On-site Shingles) shall be disposed in
accordance with all applicable Federal, State, and local
requirements. All off-site disposal activities must comply with
EPA's Revised Procedures for Implementing Off-Site Response Actions
(Off-Site policy).
The selected remedy does not address the off-site Shingle Pile on
the Hillsborough County property adjacent to the Bay Drums site.
EPA, the State of Florida, and Hillsborough County are currently
evaluating options for addressing this material.
General Components
The entire site shall be fenced with a new eight-foot security
fence topped with three strands of barbed wire. Warning signs
shall be placed at appropriate intervals, indicating that hazardous
substances are disposed at the site and providing EPA' s phone
number for information on the site. Any existing site fencing
shall be removed and salvaged or disposed as non-hazardous in an
off-site landfill.
During design, the impacts of construction activities on site
drainage patterns shall be evaluated to determine if additional
drainage ditches must be constructed. At a minimum, it is expected
that a drainage ditch surrounding the surface cap will be necessary
to manage drainage from the cap. In general, vegetated open
trapezoidal channels will be used to accomplish this purpose.
Monitoring of surface water and sediment runoff from the site shall
be conducted to evaluate the effectiveness of the soil cover in
40
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41
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preventing impacts to the wetlands. The frequency and duration of
this monitoring shall be established during the Remedial Design.
Deed notices shall be filed with Hillsborough County advising that
hazardous substances are disposed on-site. Addi tionally, the
notice shall restrict the use of the site to activities which do
not compromise the effectiveness or integrity of the remedial
action.
Finally, groundwater monitoring shall be conducted on an annual
. basis. In general, analyses for lead and chlordane shall be
performed on samples from both the surficial and Floridan ~quifers.
EPA anticipates that this portion of the source control remedy will
be conducted in conjunction with the area-wide groundwater remedy.
EPA will conduct a formal review (Five Year Review) of the data
five years after initiation of the remedial action and every five
years thereafter to evaluate the effectiveness of the remedy. This
review is required under Section 121 of CERCLA to assure that human
heal th and the environment are being protected by the remedial
action being implemented. Based on this review, EPA will make a
determination as to whether groundwater monitoring and Five Year
Reviews should continue, additional remedial action is required, or
the source control remedy is operating properly. Final delisting
of the site depends upon the effective operation of all operable
units for the site.
ARARs Addressed bv the Selected Remedy
Those ARARs which specifically relate to the selected remedy are
presented below. This list is not exhaustive, and EPA may
determine that other requirements are appropriate for chemicals or
conditions encountered or actions taken at the site. The major
federal ARARs which shall be attained by the selected remedy are as
follows:
o
Safe Drinking Water Act, 40 CFR 141.11-141.16, 141.50-
141.51.
o
RCRA Toxicity Characteristics Rule, 55 FR 11798.
o
Clean Air Act, 40 CFR 50, National Ambient Air Quality
Standards.
o
Endangered Species Act, 50 CFR Part 402.
o
National Emission Standards for Hazardous Air Pollutants
(NBSHAP), 40 CFR Part 61.240-247.
The major State ARARs which shall be met by the selected remedy are
as follows:
o
Florida Drinking Water Standards, FAC 17-550.
43
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o Florida Rules on Hazardous Waste Warning Signs, FAC 17-
736.
0 Florida Air Pollution Rules, FAC 17-2.1.
0 Florida Ambient Air Quality Standards, FAC 17-2.3.
The Land Disposal Restrictions (LDRs) identified in 40 CFR 268 are
not ARARs for the selected remedy for the Bay Drums site since no
listed wastes are present at the site, and leaching tests conducted
during the RI demonstrated that site soils were not characteristic
hazardous wastes as defined in RCRA (40 CFR 261). However, the
RCRA Toxicity Characteristics Rule does provide performance
standards for leaching potential for lead and chlordane.
9.1
Remedial Action Obiectives
As a part of the Baseline Risk Assessment presented in the RI,
remedial action objectives (RAOs) for soils and sediments were
determined for several exposure scenarios and various carcinogenic
risk levels. Based on the industrial character of the facilities
surrounding the Bay Drums site and the expectation that the area
will remain industrial in the future, EPA determined that a cancer
risk of 10-4 for a current worker scenario is appropriate for the
site. Based on the data collected to date, none of the
carcinogenic risk levels were exceeded in the soils, sediments or
surface water. Although the noncarcinogenic exposure point
concentration for chlordane for the current worker scenario did not
exceed the RACs, certain hotspot areas did exceed RAOs and will
require remediation. Additionally, the noncarcinogenic RAO for
lead was exceeded. A summary of the RAOs for these two
constituents is presented in Table 9.
RAOs for soils and sediments that are protective of groundwater
were also developed for those contaminants at the site which were
present in both soil and groundwater. Straight partitioning and
the SUMMERS model were used to develop groundwater protection RAOs
for five contaminants, including ethyl benzene, toluene, xylene,
naphthalene, and lead. Of these constituents, lead was the only
one which exceeded its groundwater protection RAO of 284 ppm.
9.2
Perfo~e Standards
Based on the RACs identified in Section 9.1, performance standards
for excavation and treatment of soils and sediment were developed
to protect human health, to prevent contamination of the
groundwater, and to be in compliance with ARARs. Excavation and
dredging shall continue until the remaining soils and sediments are
at or below the performance standards. All excavation shall comply
with ARARs, and testing methods approved by EPA shall be used to
determine whether the performance standards have been achieved.
Based on the appropriate risk levels and groundwater protection
standards for the site, the performance standards for the chemicals
44
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Table 9.
Remedial action objectives for soils and sediment.
Constituent Non- Risk- Groundwater Final RAO
Carcinogenic Based Protection (mg/kg) 1
RAO (mg/kg) RAO RAO (mg/kg)
(mg/kg)
SOILS
Chlordane 1802 5003 na4 180
Lead 4255 na6 2847 284
SEDIMENTS
Chlordane 2508 18009 na 250
Lead na10 na 284 284
1
The most conservative of the
groundwater protection standard.
non-carcinogenic,
risk-based,
or
2
For total chlordane, which represents a summation of seven constituents
of chlordane.
3
Based on the 10-4 risk for the Current Worker scenario.
4
No groundwater protection standard for chlordane was calculated because
chlordane was not detected in the groundwater.
Remediation goal based on the EPA Optake/Biokinetic (UBK) Model. This
model only calculates acceptable exposure concentrations for a Future
Child Resident scenario.
5
6
Lead does not have an Agency-verified carcinogenic slope factor, so a
remediation goal based on the carcinogenic potential of lead cannot be
evaluated.
7
Based on the average of the groundwater protection standards generated
for the Peak Oil, Reeves, and Bay Drums sites.
8
This non-carcinogenic goal option for chlordane in sediment was
inadvertently omitted from the baseline risk assessment contained in
the RI, but has been supplied here for determining applicable remedial
action objectives.
9
All dermal and ingestion exposures to sediments were evaluated for a
CUrrent Child Trespasser scenario.
Lead in aediment was not evaluated with the lead OBK model.
10
45
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of concern which shall be achieved by the selected remedy are as
follows:
Chemical
Performance
Standards (mq/kq)
Lead
284
Chlordane
180
After the material that is contaminated above the performance
standards is excavated or dredged, it is to be stabilized. Based
in part on discussions with FDER and EPA technical staff and the
guidelines provided in the EPA publication Stabilization/
Solidification of CERCLA and RCRA Wastes (EPA/625/6-89/022, May
1989), EPA has determined that the following performance standards
for the stabilized material shall be met:
Parameter
Performance Standard
Test. Method
Permeability
~ 10-7 em/see
Unconfined
Compressive
Strength
>
250 psi
EPA Method 9100-
SW846
ASTM 1633-84
Leachability
< 5 mg/l Lead
< .03 mg/l Chlordane
~ 10-12 mg/l
TCLP
Leachability
Modified ANS 16.1
For the low permeability surface cap, the following performance
standard shall apply:
Parameter
Performance Standard
Test Method
permeability
~ 10-7 em/see
AS'rM D1557
equivalent
or
Because certain performance st~ndards may not be determined until
the Remedial Design phase, the list of performance standards in
this section is not considered to be exhaustive and may be subject
to modification by the Agency during RD/RA implementation.
10.0 STAT11'1'ORY DB'l'BRKIRATIONS
Under CERCLA Section 121, EPA must select remedies that are
protective of human health and the environment, comply with
applicable or relevant and appropriate requirements (unless a
statutory waiver is justified), are cost-effective, and utilize
permanent solutions and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable.
46
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In addition, CERCLA includes a preference for remedies that employ
treatment that permanently and significantly reduces the volume,
toxicity, or mobility of hazardous wastes as their principal
element. The following sections discuss how the selected remedy
meets these statutory requirements.
10.1 Protection of Human Health and the Environment
The selected remedy protects human health and the environment by
immobilization of contaminants in the stabilized matrix and
disposal of the matrix above the water table. Stabilization will
reduce the mobility of contaminants in the soil, thereby"reducing
the risk associated with further degradation of on-site
groundwater. Capping of the treated soils with a low permeability
soil cover will eliminate the risks associated with direct contact
of lead and pesticide-contaminated materials. Additionally, the
topsoil and vegetated cover over the remaining portions of the site
will prevent runoff potentially affected by residual contamination
below performance standards from impacting adj acent wetlands.
Finally, fencing and deed notices will restrict access to the site,
further reducing the potential for exposure.
10.2 Compliance with APplicable
Reauirements (ARARs)
Relevant
and
APpropriate
or
The selected remedy of excavation, stabilization/solidification,
on-site disposal, and capping of contaminated soils and sediments
will comply with all applicable or relevant and appropriate
requirements (ARARS). The ARARs are presented below:
Chemical-Specific ARARs
o
Safe Drinking Water Act, 40 CFR 141.11-141.16, 141.50-141.51.
Treatment technique action level for lead is relevant and
appropriate in development of soil action levels which are
protective of site groundwater.
o
Florida Drinking Water Standards, FAC 17-550. Maximum
contaminant level for lead is relevant and appropriate for
development of soil action levels protective of groundwater.
o
Clean Air Act, 40 CFR 50. Provides National Ambient Air
Quality Standards which are relevant and appropriate to lead
and particulate emissions resulting from remedial activities
conducted at the site.
o
Florida Ambient Air Quality Standards, FAC 17-2.3. Relevant
and appropriate to remedial activities conducted at the site
which may generate lead and particulate emissions.
RCRA Toxicity Characteristics Rule, 55 FR 11798. Relevant and
appropriate in providing performance standards for lead and
chlordane for TCLP testing of stabilized material.
o
47
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Location-Specific ARARs
o
Endangered Species Act, 50 CFR Part 402. Applicable to site
construction activities which may impact the critical habitat
of endangered or threatened species present in the site area.
Florida Rules on Hazardous Waste Warning Signs, FAC 17-736.
Identifies requirements applicable to signs around perimeter
and at entrances of site.
o
Action-Specific ARARs
o
National Emission Standards f~r Hazardous Air Pollutants
(NESHAP), 40 CFR Part 61.240-247. Relevant and appropriate to
the handling of asbestos-contaminated shingle debris (On-site
Shing les ) .
Florida Air Pollution Rules, FAC 17-2.1. Applicable to
remedial activities conducted at the site which may generate
air emissions.
o
10.3 Cost Effectiveness
EPA believes this remedy will eliminate the risks to human health
at an estimated cost of $2,680,000. This alternative is the least
expensive of the remaining alternatives. Even at a lower cost, the
selected remedy provides an additional measure of protectiveness
over Alternative 2 by providing treatment of the waste material,
and it provides additional groundwater protection over Alternative
3 by ensuring the disposal of treated materials above the water
table. Finally, it avoids potentially costly administrative delays
which are often associated with off-site disposal actions such as
Alternative 5.
10.4 Utilization of Permanent Solutions to the lfayimum 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 source control
operable unit at the Bay Drums site. Of those alternatives that
are protective of human health and the environment and comply with
ARARs, EPA has determined that the selected remedy provides the
best balance of trade-offs in terms of long-term effectiveness and
permanence, reduction in toxicity, mobility, or volume achieved
through treatment, short-term effectiveness, implementability, and
cost, while also considering the statutory preference for treatment
as a principal element and considering state and community
acceptance.
The selected remedy will address the principal threats posed by the
soils and sediments through stabilization/solidification, achieving
significant reductions in the mobility of lead and chlordane. This
48
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remedy provides more or equally effective treatment as any of the
alternatives considered, and it will cost less than any alternative
except No Action. The treatment of the contaminated soils and
sediment is consistent with program expectations that indicate that
highly toxic and mobile wastes are a priority for treatment and
often necessary to ensure the long-term effectiveness of a remedy.
10.5 Preference for Treatment as a Principal Element
By immobilizing the contaminants in a stabilized matrix, the
selected remedy addresses one of the principal threats posed by the
site through the use of treatment technologies. The threat posed
by contaminated groundwater at the site will be addressed by the
Area-Wide Groundwater remedy.
11.0
DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for the Bay Drums site, which was released for
public comment in August 1992, identified Alternative 4 as the
preferred alternative for soil and sediment remediation. EPA
review~d all written and verbal comments submitted during the
public comment period. As described in the FS, the Proposed Plan
included a 4 inch topsoil cover as part of the revegetation of the
site. However, based on comments received from the natural
resource trustees and FDER, EPA added a requirement to increase the
topsoil cover on remaining portions of the site from 4 inches to 1
foot to prevent runoff potentially affected by residual
contamination below performance standards to impact adjacent
wetlands. Monitoring of surface water and sediment runoff from the
site will also be required to evaluate the effectiveness of the
soil cover. This change will result in an estimated increase of
$36,000 in the overall cost of the selected remedy. No other
significant changes to the remedy, as originally identified in the
Proposed Plan, were necessary.
49
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