United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-90/070
June 1990
&EPA Superfund
Record of Decision:
62nd Street Dump, FL
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50272.101
REPORT DOCUMENTATION 11. REPORT NO. I 2. 3. Reciplenl'o Acceoaion No.
PAGE EPA/ROD/R04-90/070
4. Title and Subtitle 5. Report Date
SUPERFUND RECORD OF DECISION 06/27/90
62nd Street Dump, FL
6.
First Remedial Action - Final
7. Author(a) 8. Performing Organization Repl No.
II. Pllrfonnlng Orgalnlzadon Name and Addr..a 10. ProjecVTaaklWork Unit No.
11. Contract(C) or Grant(G) No.
eC)
(G)
12. ~oring Organlullon Name and Addre.. 13. Type of Repor1 & Period Covered
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
15. Suppl8m8n1ery NoIe8
18. Abatr.a (Uml1' 200 word.)
The 5-acre 62nd Street Dump site is an inactive industrial waste disposal area in Tampa,
Hillsborough County, Florida. Several marsh areas and a series of fish breeding ponds
lie adjacent to the site. Surrounding land use is mixed light industrial and
residential. The site overlies a series of sedimentary rock aquifers, which are
currently used as drinking water sources. In the mid-1970s, the site was used as a sand
borrow pit. After this operation halted, industrial wastes, including auto parts,
batteries, and kiln dust were dumped on site. Industrial dumping ceased in 1976, but
unauthorized onsite dumping of construction materials and household garbage continued.
In 1976, fish kills occurred in the adjacent ponds, which lead to site investigations in
1979 and 1980 by private groups. Based on these investigations, the contamination was
determined to be the result of waste material leaching from the landfill. Several
additional investigations were conducted from 1983 to 1989 to identify and further
characterize contaminant sources and contaminated media. This Record of Decision (ROD)
addresses source remediation and onsite and offsite ground water contamination. The
primary contam~~an~s of concern affecting the soil, debris, and ground water are
organics includ.i'ng PCBs; and metals including arsenic, chromium, and lead.
(See Attached Page)
17. Documenl An8Jya18 .. D8ec:rtplO"
Record of Decision - 62nd Street Dump, FL
First Remedial' Action - Final
Contaminated Media: soil, debris, gw
Key Contaminants: organics (PCBs), metals (arsenic, chromium, lead)
b. ~dfl8r8l0pen-Ended Tenne
c. CooA TI FJeld/Group
18. Av.U.biDly 5I.tament 19. Security Cle.. (Thia Report) 21, No. 01 Plgea
None 83
20. Security Cia.. (Thia Page) 22. Price
None
~r 2 (4.77)
(S. ANSl-Z3II.18)
See Insltucuons on Reverse
(Formeriy NTlS-35)
Department 01 Commerce
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EPA/ROD/R04-90/070
62nd Street Dump, FL
First Remedial Action - Final
Abstract (Continued)
The selected remedial action for this site includes dewatering and excavating
approximately 48,000 cubic yards of contaminated soil and non-cement debris, followed by
onsite treatment using solidification/stabilization, and placing the treated material
onsite within the original dump area; capping the site with an impermeable membrane and
vegetative soil cover; pumping and onsite treatment of contaminated ground water using
chromium reduction, flocculation, sedimentation, and filtration, followed by offsite
discharge to a publicly owned treatment works (POTW) or onsite discharge to surface
water; disposing of residual sludges onsite; monitoring ground water; and implementing
institutional controls including land use restrictions. The estimated present. worth cost
for this remedial action is $16,460,000, which includes an estimated present worth O&M
cost of $690,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS: Federal MCLs were chosen as cleanup standards for ground
water. Chemical-specific goals include chromium 50 ug/l (MCL) and lead 15 ug/l (proposed
MCL). Soil cleanup criteria were chosen as the more stringent of health-based criteria
or values calculated from a leachate model. Chemical-specific goals for soil include
PCBs 0.33 mg/kg, arsenic 3.5 mg/kg, chromium 8.8 mg/kg, and lead 17.4 mg/kg.
".
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Record of beci~ion
Declaration
SITE NAME AND LOCATION
62nd Street Site
Tampa, Hillsborough County, Florida
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the
62nd Street Site, in Tampa, Hillsborough County, Florida, which was
chosen in accordance with CERCLA, as amended by SARA, and, to the
extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision is based on the
administrative record file for this site.
The State of Florida concurs with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of .Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE REMEDY
'rhis remedy is the final action for the site. The function of
remedy is to reduce the risks associated with exposure to
contaminated onsite soils, and contaminated groundwater in the
surficial aquifer onsite and offsite.
. .
", "
The major components of the selected remedy include:
Solidification/stabilization of the battery wastes,
shredded auto parts, and contaminated soils (approximately
48,000 cubic yards). Contaminants of concern associated
with the battery wastes and shredded auto parts are
antimony, arsenic, cadmium, chromi~, copper, lead, and
polychlorinated biphenyls (PCBs).
this
No treatment of the onsite cement wastes since they present
little threat through either direct contact or leaching to
groundwater.
Capping of the entire site (approximately 5.5 acres) with a
two-foot vegetative soil cover underlain by an impermeable
membrane.
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Extraction and treatment of the groundwater from the
surficial aquifer both onsite and offsite. Contaminants of
concern in the the surficial aquifer are lead and chrornilli~.
Institutional controls or other land use restrictions to
ensure the integrity of the cap and preclude exposure to the
treated soils.
The total present worth cost for the selected remedy is $16,460,000.
STATUTORY DETE~~INATIONS
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 which reduces toxicity, mobility, or
volume as a principal element.
Because this remedy will result in hazardous substances remaining
onsite, 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.
JUN 2 7 1990
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Greer C.
Regional
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Tidwell '
Administrator
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Date
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Record of Decision
The Decision Summary
62nd Street Site
Tampa, Hillsborough County, Florida
Prepared by:
U.S. Environmental Protection
Region IV
Atlanta, Georgia
Agency
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1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
TABLE OF CONTENTS
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Site Name, Location, and Description.........................1
Site History and Enforcement Activities......................1
Highlights of Community Participation.................. ......5
Scope and Role of Response Action Within Site Strategy.......5
Summary of Site Characterizations ... .... .....................6
6. 1 Site Geology....................... . . . . . . . . . . . . . . . . . . . .6
6 . 2 Hydrology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.3 Groundwater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
6.4 Soil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.5 Sediment and Surface Water. ..... ..................... .17
Summary of Site Risks .......................................18
7.1 Identification of the Contaminants of Concern ... ..... .18
7.2 Exposure Assessment Summary ........... ............. ...18
7.3 Summary of the Toxicity Assessment of the Contaminants
of Concern......................"..................... 2 2
7.4
7.5
Characterization of Risk ............... ... .... ..... ...29
Environmental Risk.................................... 35
Description of Alternative ........ ......................... .35
8.1 Alternative 1 - No Action .............................35
8.2 Alternative 2 - Excavation of Soil and Placement in New
Onsite Landfill with Groundwater Extraction and Onsite
Trea tmen t ............................................. 36
8.3
8.4
Alternative 3 - Excavation of Soil and Offsite Disposal
with Groundwater Extraction and Onsite Treatment ..... .42
Alternative 4 - Excavation of Soil and Placement in New
Onsite Landfill with Groundwater Vertical Barrier. ....42
Alternative 5 - Soil Capping with Offsite Groundwater
Extraction and Onsite Groundwater Containment ..... ....45
Alternative 6 - Soil Capping with Groundwater Vertical
Barr ier ............................................... 46
8.5
8.6
8.7
8.8
Alternative 7 - Solidification/Stablilization of Soil
with Groundwater Extraction and Onsite Treatment..... .47
Alternative 8 - Solidification/Stablilization of
Non-Cement Wastes and Capping of Soil with Groundwater
Extraction and Onsite Treatment ........ ....... ....... .49
Summary of Comparative Analysis of Alternatives... ........ ..52
9.1 Overall Protection of Human Health and the Environment.52
9.2 Compliance with ARARs .................................52
9.3 Long-Term Effectiveness and Permanence............... .54
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9.4
9.5
9.6
9.7
9.8
Reduction of Toxicity, Mobility, or Volume of the
Contaminants Through Treatment ... ................ .....54
Short-Term Effectiveness.... . . . . . . . . . . . . . . . . . . . . . . . . . .54
Cost. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
State Acceptance.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Conununi ty Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
10.0
Selected R~medy ..................................,'.........55
10.1 Remediation Goals.............. . . . . . . . . . . . . . . . . . . . . . .56
11.0 Statutory Determinations................. . . . . . . . . . . . . . . . . . . .59
11.1 Protective of Human Health and the Environment. ... ....59
11.2 Attainment of the Applicable or Relevant and Appropriate
Requirements (ARAR) ................................... 59
11.3 Cost Effectiveness.................... ~ . . . . . . . . . . . . . . .61
11.4 Utilization of Permanent Solutions and Alternative
Treatment Technology or Resource Recovery Technologies
to the Maximum Extent Practicable ................ .....62
11.5 Preference for Treatment as a Principal Element .... ...62
11.6 Documentation of Significant Changes ............... ...62
"
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Figure 2-1
Figure 2-2
Figure 6-1
Figure 6-2
Figure 6-3
Figure 6-4
Figure 6-5
Figure 6-6
Figure 6-7
Figure 8-1
Figure 8-2
Figure 8-3
Figure 8-4
Figure 8-5
LIST OF FIGURES
Site Location Map........ . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Site Map......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Temporary and Previously Existing Monitor Well
Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Phase 1 Permanent Monitor Well Locations.......... ..10
New Shallow Monitor Well Locations ................ ..11
Surficial Aquifer Water Levels (March 1989) ....... ..12
Floridan Aquifer Water Levels (March 1989) """'" .13
Extent of Site Related Groundwater Contamination
Exceeding Cleanup Goals................... . . . . . . . . . .15
Aerial Extent of Soil Contamination (Hart, 1986) .. ..16
Soil Areas to be Excavated and Capped During
Construction of New Landfill.... ................ ....37
Cross Section of Surface Cap ..... .... ........... ....39
Conceptual Groundwater Treatment System ........ .... .40
Location of Vertical Barrier ......... ........ ...... .44
Areal Extent of Partial Solidification/Stabilization
and Total Capping................................... 50
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Table 7-1
Table 7-2
Table 7-3
Table 7-4
Table 7-5
Table 7-6
Table 7-7
Table 7-8
Table 7-9
Table 7-10
Table 7-11
Table 7-12
LIST OF TABLES
Contaminants of Concern
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Exposure Assumptions For The Direct Contact With
Surficial Soil and Test Pit Waste Soil.......... .....23
Exposure Assumptions For The Inhalation Of Surficial
Soilfi ............................................... .24
Soil Concentrat~ons (mg/kg) For Direct Contact
Scenar i08 ............................................ 25
particulate Contaminant Concentrations (ug/g) For The
Inhalation Scenarios ............................. ....26
SedLment Concentrations (mg/kg) For Direct Contact
Scenar iOB ............................................ 27
Critical Toxicity Values for Chemicals of Concern ....28
Risk Characterization For Direct Contact With Surficial
Soils And Test Pits (Current Use) ....................30
Risk Characterization For Direct Contact With Surficial
And Subsurface Soils (Future Use) ....................31
Risk Characterization For Inhalation of Surficial Soils
(Current Use) ........................................ 32
Risk Characterization For Inhalation of Surficial And
Subsurface Soils (Future Use) ........................33
Risk Characterization For Direct Contact With Pond
Sediments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 9-1,.,' '"Glossary Of Evaluation Criteria......... . . . .. . . . . . . . .53
"".
Table 10-1 Site Chemicals Exceeding Cleanup Goals .'..............58
LIST OF APPENDICES
Appendix A - Respo~siveness Summary
Appendix B - State's Concurrence Memorandum
Appendix C - Lead, Memorandum
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. RECORD OF DECISION
The Decision Summary
62nd Street Site
Tampa, Hillsborough County, Florida
1.0
Introduction
The 62nd Street Site (the Site) was proposed for inclusion on the
National Priorities List (NPL) in December 1982. The site has been
the subject of a variety of studies, including a Remedial
Investigation (RI) which was performed for the Florida Department of
Environmental Regulation (FDER) from February 1986 to September 1987
by a team of contractors consisting of Mayes, Sudderth and
Etheredge, Inc. (MSE), Fred C. Hart and Associates, Inc. (Hart), and
Universal Engineering Testing Company, Inc. (UETC). FDER also
conducted the Feasibility Study (FS) for the Site under a contract
with Camp Dresser & McKee, Inc. (COM). The FS, which develops and
analyzes potential alternatives for remediation at the site, was
issued to the public on March 22, 1990. The FS also supplements the
RI by conducting additional field activities to characterize the
nature and extent of soil, sediment, surface water, and groundwater
contamination at the Site.
2.0
Site Name, Location, and Description
The 62nd Street Site is located in Tampa, Hillsborough County,
Florida, north of Columbus Drive and just west of 62nd Street
(Figure 2-1). The Site is a five and a half acre dump formerly used
for the disposal of industrial waste. The Site is located in an
area with mixed residential and light industrial land use. The Site
is bounded on the west by a series of what were small, shallow fish
breeding ponds. To the east and south of the Site are residential
areas interspersed with light commercial and industrial operations.
To the north of the Site is undeveloped land. The current landowner
operates an automobile scrap yard on the southern portion of the
Site. A site map is presented as Figure 2-2.
3.0
Site History and Enforcement Activities
The 62nd Street Site was operated for a limited
approximately three years in the mid-1970s as a
sand was excavated and sold. When the owner of
operation of the borrow pit, he allowed several
to use the remaining pit as a disposal area for
materials, including shredded automobile parts,
duration of
borrow pit; that is,
the Site ceased
companies in Tampa
various waste
batteries, waste
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R£l8ENCE; TAMPA QUADRANGLE
USGS 7.S MINUTE SERIES
CAMP DRESSER &; McKEE INC.
SITE LOCATION MAP
62nd STREET SITE
TAMPA, FLORIOA
FIGURE NO.
2-1
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SITE MAP
62nd STREET SITE
TAMFlA, FLORIDA
FIGURE NO
2-2-
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cement, kiln dust, and kiln liners. The owner ceased dumping in
1976, but unauthorized dumping of household garbage and construction
debris continued after this date. '
In 1976, the potential for environmental problems at the Site was
recognized when fish kills occurred in fish breeding ponds on the
adjacent property belonging to Peninsular Fisheries. On November
30, 1976, the Hillsborough County Environmental Protection
Commission (EPC) 'issued a notice to cease all disposal activities at
the site. The first major investigation at the Site was conducted
in June 1979 by Fish Doctors Laboratory, Inc. (FDL) under contract
to Peninsular Fisheries, Inc.
The study from FDL determined that several parameters in the fish
breeding ponds were present in levels unsuitable for fish'
habitation. These parameters included copper, detergent, dissolved
oxygen, iron, turbidity, and biological oxygen demand. Systems
Engineering Associates (SEA), representing Peninsular Fisheries,
Inc., concluded in June 1979 that leaching of the concrete material
on the western portion of the Site could result in excessive
alkalinity in the ponds. SEA further concluded that liquids
resulting from onsite disposal of battery casings could adversely
impact fish breeding in the adjacent ponds by lowering the pH and
causing sulfate poisoning.
Additional ,work was conducted in 1980 by Seaburn and Robertson, Inc.
to evaluate the impact of the Site on the adjacent fish ponds. This
report concluded that there was a hydraulic connection between the
dump Site and the fish ponds. The report further concluded that the
dump Site was adversely impacting the water quality in the fish
ponds.
Environmental sampling was conducted periodically by the
Hillsborough County EPC and by the Florida Department of
Environmental Regulation (FDER). The areas sampled included private
wells, fish breeding ponds, a shallow sand point well installed by
FDER, and"~arious areas surrounding the Site. An analysis of the
sample from'the shallow sand point well showed groundwater
contamination exceeding the FDER Chapter 17-3 standard for
chromium. However, 1982 FDER analyses of water samples from wells
upgradient and downgradient of the Site did not show any metals
concentrations above background leve~s.
A Remedial Action Master Plan (RAMP) was prepared for the 62nd
Street Site by NUS Corporation under contract to EPA in June 1983.
A preliminary risk assessment was performed as a part of RAMP
development, and an approach to both short- and long-term remedial
actions was developed. The RAMP indicated that there was no
immediate concern over drinking water contamination, but that
groundwater monitoring should be continued and a feasibility study
conduct~d to evaluate long-term remediation.
-4-
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In March 1984, the FDER and the EPA entered into a Cooperative
Agreement to conduct a Remedial Investigation/Feasibility Study
(RI/FS) at the Site. The RI was conducted in 1986 by a team of
several consulting firms consisting of Mayes, Sudderth & Etheredge,
Inc., Fred C. Hart Associates, Inc., Universal Engineering Testing
Company, Inc., and Compuchem Laboratories, Inc. The field
activities were conducted in two phases. Phase I was conducted in
February 1986, and consisted of construction and sampling of 12 test
pits across the Site. Phase II was conducted in July and August
1986, and involved installing and sampling 14 groundwater monitor
wells, sampling of 10 domestic wells, sampling surface water and
sediment from the fish ponds, and sampling onsite surface soils.
Additional sampling of onsite monitor wells was conducted in 1987 by
both Environmental Science and Engineering and the U.S.
Environmental Protection Agency (EPA). Camp Dresser & McKee, Inc.
(COM) was contracted by FDER in August 1988 to conduct a Feasibility
Study (FS) for the Site. The FS developed and analyzed potential
alternatives for remediation at the Site. The FS also supplemented
the RI by conducting additional field activities to characterize the
nature and extent of soil, sediment, surface water, and groundwater
contamination at the Site. In July 1989, additional domestic well
sampling was performed by the Florida Department of Health and
Rehabilitative Services (HRS).
4.0
Highlights of Community Participation
The RIfFS and the Proposed Plan for the 62nd Street Site were
released to the public on March 21, 1990. These two documents were
made available in both the administrative record and an information
repository maintained at the EPA Docket Room in Region IV and at the
Tampa-Hillsborough Public Library. The notice of availability was
published in the Tampa Tribune on March 22, 1990. A public comment
period was held from March 23, 1990 through April 23, 1990. In
addition to public comment and the accessibility of the information,
a public meeting was held on March 29, 1990. At this meeting,
representatives from FDER and EPA answered questions and addressed
community concerns. A response to comments received during this
period is included in the Responsiveness Summary, Appendix A of this
Record of Decision. This decision document presents the selected
remedial action for the 62nd Street Site, chosen in accordance with
CERCLA, as amended by SARA and, to the extent practicable, the
National Contingency Plan. The decision for this site is based on
the administrative record.
5.0
Scope and Role of Response Action Within Site Strategy
This ROD addresses the source of contamination, the landfill. The
battery wastes, shredded auto parts, and soil at the Site, found to
be contaminated with antimony, arsenic, cadmium, chromium, copper,
lead, and polychlorinated biphenyls (PCBs), pose the principal
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i
I
I
I
threat to human .health and the environment because of the risks
associated with possible ingestion or dermal contact. Also, the
shallow groundwater aquifer, found to be contaminated above
health-based levels with cadmium, chromium, and lead, has migrated
offsite. Although this aquifer is not the source of drinking water
for the local residents, under future use scenarios, it presents a
threat to human health and the environment. The cleanup objectives
for this ROD are to prevent current or future exposure to the
contaminated soi1 and groundwater through treatment and containment,
and to reduce the migration of contaminants.
6.0
Summary of Site Characterizations
The Site has been used in the past for excavation to obtain fill
material. Borrow pits resulting from the excavation were used for
dumping a variety of waste materials including shredded automobiles,
tires, batteries, vinyl seats, and Portland cement stack dust.
Plastic battery casing chips have been observed on the ground
surface in several locations in the southern and western areas of
the Site. Activities conducted by the current site owner involve
the storage of scrap automobile parts and other scrap metal.
Wastes buried at the Site fall into two categories: auto.
part/battery wastes and cement wastes. The disposal,of the auto
part/battery wastes at the Site has resulted in the release of
hazardous substances including c;intimony, arsenic, cadmium, chromium,
copper, lead, and polychlorinated biphenyls (PCBs) in the soil. The
surficial aquifer both onsite and offsite is also contaminated with
cadmium, chromium, and lead above health-based levels. The cement
wastes represent little threat through either direct contact \or
leaching to groundwater.
. 6'.1
Site Geology .
The genera~"geology of the Tampa area, including the 62nd Street
Site, is that of a series of sedimentary sequences of rock and
unconsolidated sediments overlying a basement of crystalline igneous
or metamorphic rock. The basement rock is of Paleozoic age and the
s~dimentary sequences become younger upwards from the basement
rock. The sedimentary rocks range in age from Mesozoic through
Cenozoic with Pleistocene sediments of the Cenozoic being the
youngest. Sedimentary rocks in the Tampa area consist of
limestones, sand, clay, and silt. The variability of rock and
sediment types suggests environments of deposition ranging from open
ocean to shoreline to lagoons and tidal marshes.
Lithologic and paleoenvironmental evidence in the Tampa area and
much of Florida suggests that the sedimentary layers of rocks and
sediments were laid down during a series of transgressive
(shoreward) and regressive (receding) shoreline migrations. Rock
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and sediment sequences which are present and of concern at the 62nd
Street Site are the Tampa limestone, Hawthorn Formation and
undifferentiated Pliocene, Pleistocene, and recent deposits.
The Tampa limestone, the oldest unit of concern, is early Miocene in
age and consists of 50ft, white, impure limestones. The unit
contains some beds of calcareous sands and clayey sands. Much of
the unit contains soft lime muds, solution cavities, and sinkholes
and, therefore, ~s highly porous in some zones. Its porous nature
permits large volumes of water to flow through, giving it good
aquifer characteristics. Water quality in the Tampa limestone is
generally good.
The upper part of the Tampa limestone is high in clay content,
making the contact between it and the Hawthorn limestone difficult
to determine. Throughout this document, the Tampa limestone is
referred to as the lower aquifer or Floridan aquifer.
The Hawthorn Formation is very thinly represented, if at all, at the
62nd Street Site, and consists of a phosphatic clay unit. The
Hawthorn is known to contain montmorillonite clays. These clays are
characterized by swelling when hydrated and having the ability to
absorb and retain certain ions in an exchangeable state. The clay
units age is late Miocene. This unit, along with the very top
portion of the Tampa limestone, is referred to as the confining
unit.
The undifferentiated Pliocene, Pleistocene, and recent deposits
overlie the Hawthorn and Tampa limestone. They were formed by
glacial periods which caused fluctuations in sea level. These
fluctuations left varying thicknesses of fine grained quartz sands
throughout the Tampa area, with the thickness of the sands in the
62nd Street Site being approximately 20 feet. As the deposits allow
water to be transmitted through them, they can generally be termed
an aquifer, in their natural state. Water quality in this aquifer
is suitable for domestic and municipal supplies, although in some
locales there is high iron content in the water. These deposits are
referred to as the upper sand aquifer in this document.
6.2
Hydroloqy
Surface water flows at the site are influenced by relatively small
elevation changes. This is due to the flat topography of the site
area. The topographic low of the site occurs at the southwest
corner and local residents report that a considerable amount of
standing water is present in this area during wet periods of the
year. Just prior to the public meeting for this Record of Decision,
the current landowner dug a trench through this low area to allow
the Site to drain to the west into a small drainage ditch offsite.
As part of the Remedial Design for the Site, samples will be taken
in the drainage ditch to see if contamination has migrated offsite
as a result of the new onsite trench.
-7-
-------
A small surface water diversion berm originates along the
southwestern boundary of the site and extends along the western
boundary to the northern portion of the site. Small onsite
depressions are a1so present, resulting in the formation of marshy
areas during the majority of, the year.
Site-wide surface water flows from a topographic high at the
northeastern corner of the site to a low in the southwestern
corner. The diversion berm then acts as a conduit to 'transmit
surface water to the northwestern corner of the site and ultimately
into the series of interconnected fish ponds. Two drainage ditches
are present on the ,adjacent property to the west of the site which
are reported to drain into Palm River, which runs into McKay Bay.
These drainage ditches are the major transmission vehicle for
movement of surface water from the site and the adjacent fish pond
area. In addition to the presence of numerous fish ponds located
Lrnmediately west of the site, a large lake is located approximately
1,500 feet to the northwest of the site.
6.3
Groundwater
The groundwater sampling activities during the RI consisted of the
sampling of offsite domestic wells, and the installation and
sampling of 14 onsite monitor wells. All offsite domestic wells
were completed in the Floridan aquifer and their locations were
selecte~ to define background water quality and to detect any,
offsite migration of contaminants. Fourteen monitor wells, ten in
the surficial aquifer and four in the Floridan aquifer, were
installed onsite.
The RI sufficiently identified the. contamination onsitej however, it
was not of sufficient scope to thoroughly define the extent of
offsite contamination. Therefore, additional field investigations
were conducted as a component of the FS to supplement the existing
data. The additional work was conducted in two phases with data
obtained fr~m Phase I used to guide field operations in Phase II.
During Phase I, a series of 10 temporary groundwater monitor wells
were added in the surficial aquifer offsite. Figure 6-1 shows the
locations'of the temporary monitor wells added during Phase I of the
FS and the monitor wells installed during the RI.
, ,
Eight permanent groundwater monitor wells were installed in four
clusters, with two wells at each cluster. One well at each cluster
was drilled to the surficial aquifer and the other well to the.
Floridan aquifer. Figure 6-2 shows the eight permanent offsite
wells added during the Phase I of the FS.
Phase II added seven more permanent monitor wells in the surficial
aquifer. Figure 6-3 shows the locations 9f the seven additional
wells added during the Phase II of the FS.
Water level measurements were taken in all of the welis and water
contour maps were drawn for the surficial aquifer (Figure 6-4) and
the Floridan aquifer (Figure 6-5).
-8-
-------
,/
/1
I
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LEGEND
62nd
STREET
SITE
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CAMP DRESSER & McKEE INC.
TEMPORARY AND PREVIOUSLY EXISTING
MONITOR WELL LOCATIOOS
62nd STREET SITE
TAMPA. FLORIDA
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CAMP DRESSER & McKEE INC.
PHASE I PERMANENT MONITOR WELL LOCAT1OHI
62nd STREET SITE
TAMPA, FLORIDA
FIGURE NO.
6-2
I
-------
LEGEND
.
NEW SHALL.O-W "'ONITOR WE.!.L
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CAMP DRESSER & McKEE INC.
NEW SHALLOW MONITOR WEll lOCATIONS
62nd STREET SITE
TAMPA, FLORIDA
FIGURE NO.
6-3
-ll-
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LEGEND
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CAMP DRESSER & McKEE INC.
SURFICIAL AQUIFER WATER LEVELS - MARCH 1989
62nd STREET SITE
TAMPA, FLORIDA
FIGURE NO.
6-4
- 1 '" -.
-------
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LEGEND
A 18U...AH[PlT 11101'111011 W£LJ..
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CAMP DRESSER & McKEE INC.
FLORIDAN AQUIFER WATER LEVELS - MARCH 1989
62nd STREET SITE
TAMPA, FLORIDA
FIGURE NO.
6-5
-13-
-------
Analytical data collected from the groundwater sampling events
performed in the RI and the FS found that the surficial aquifer was
contaminated with lead, chromium, arsenic, and cadmium at levels
exceeding the' Safe Drinking Water Act (SDWA) Maximum Concentration
Limits (MCLs). The most common contaminant exceeding the MCL was
chromium, with eight wells showing values above the 50 ppb MCL (the
highest value was 544 ppb). Chromium was also detected in levels
exceeding the MCL in the upgradient well, indicating a second source
of contamination in the area.
The second most common contaminant was lead with a current MCL of 50
ppb. Four wells exceeded the MCL for lead (the highest value was
399 ppb). The current MCL of 50 ppb for lead was established as an
interim drinking water regulation in 1975. Since that time,
considerable huma~ health information has been produced that
indicates that the level may not be protective for young children.
EPA has issued a memorandum stating that a lower level of 15 ppb
lead is more protective to human health and the environment than the
current MCL of 50 ppb. A copy of this memorandum is included as
Appendix C. Nine wells exceed the recommended 15 ppb lead value.
Arsenic was present above the 50 ppb MCL in one well, with a
reported value of 65 ppb. Cadmium was present above the 10 ppb MCL
in one well, with a reported value of 12 ppb.
None of the samples taken from the deep Floridan wells or the
domestic wells showed site-related contaminants of concern above the
SDWA MCLs. However, the domestic wells did show violations of
secondary water quality standards.
Figure 6-6 shows the extent of site-related groundwater
contamination in the surficial aquifer exceeding the cleanup goals.
Since the lead plume is entirely contained within the chromium
plume, chromium will be the main contaminant of concern during
cleanup. The presence of chromium in groundwater is assumed to be
mostly in its more toxic hexavalent state. The shape of the plume
appears to ~e in accordance with the flow direction estimated in
Figure 6-3" -.. However, chromium contamination detected upgradient and
to the north. of the site were not included when defining the plume.
Accordingly, this Record of Decision does not take into account the
upgradient and offsite contamination which appears to be. caused by a
source not related to the 62nd Street Site. The areal extent of the
estimated chromium plume which is 20 be addressed with .the selected
remedy is approximately 678,436 ft (about 16 acres).
6.4
Soil
Test pit samples of subsurface soil were taken to determine the
physical and chemical properties of the wastes and to determine the
vertical and horizontal extent of each waste type, including the
cement wastes, automobile parts, and battery casings. Figure 6-7
-14-
-------
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FIGURE NO.
CAMP DRESSER & McKEE INC.
EXTENT OF SITE-RELATED GROUNDWATER
CONTAMINATION EXCEEDING CLEANUP GOALS
62nd STREET SITE
TAMPA. F~CRIOA
6-6
_1c::.-
-------
62nd
STREET
I '.' SITE
c:JG ~
L:J c::=J
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D C::) I
00 50 0 50
P-t~...... .
3~ SCALE IN FEET
~
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///// ////
LEGEND
<::;:::J . + '00' SOIL .COIC
n D
:? v
.' .
SOURCE: FRED C. H RT ASSOCIATES, INC.. 1986
CAMP DRESSER & McKEE INC. FIGURE NO
AREAL EXTENT OF CONTAMINATION (HART, 1986)
62nd STREET SITE
TAMPA, FLORIDA
6-7
-16-
-------
represents the areal extent of soil contamination according to each
waste type.
The site is a threat to the human health and the environment due to
the presence of antimony, arsenic, cadmium, chromium, copper, lead
and polychlorinated biphenyls (PCBs).
Backqround Range (ppm)
Site Ranqe (ppm\
AAt~o~
Arsenic
Cadmium
Chromium
Copper
Lead
PCBs
2 10
1 50
0.01 - 0.7
1 - 1,000
2 100
2 200
o
0.14
0.084 -
0.01
0.13
0.15
0.05
0.09
512
72
49
210
- 43,000
- 20,000
11
Extraction Procedure (EP) toxicity tests were performed on three of
the soil samples. The analysis indicated that the site materials
were toxic only for lead. However, the pH in the groundwater ranged
from 11 to 12.5. Under such high pH conditions, the metals were
probably in an insoluble hydroxide form. Since the water samples
were not filtered, these metal hydroxides may have been dissolved by
the acid preservative in the sampling bottle.
6.5
Sediment and Surface Water
Sed~ent and surface water samples were obtained from the offsite
fish ponds and drainage ditches on the western side of the site.
These fish ponds are the apparent receptors of surface water runoff
from the site. Therefore, any site-related surface water or
particulate contamination could be identified through pond
sampling. AAalyses of the sed~ent and surface water samples
consisted of testing for inorganic, volatile organic, semi-volatile
organic chemicals, and polychorinated biphenyls.
Sed~ent samples collected from the fish ponds by Hart Associates
indicated the presence of high levels of iron, which is considered
to be naturally occurring. A number of other metal constituents
were present at relatively low levels, again at levels considered to
be within expected background ranges. Sediment sampling conducted
during the FS were consistent with the 1986 RI findings, with the
exception of a few organic compounds which were detected either at
low levels or reported as est~ated values. The impact of these
organic chemicals was evaluated in the risk assessment portion of
the FS, and the results of this analysis indicate that the chemicals
present in the pond sediments do not pose a risk to human health
and/or the environment. Therefore, no remediation of sed~ents is
necessary at the fish ponds located adjacent to the site.
Results from both the RI and the FS indicate that concentrations of
all the offsite surface water samples were below the Ambient Water
-17-
-------
Quality Criteria (AWQC). As no permanent surface water bodies exist
on the 62nd Street Site and contaminant levels in the offsite ponds
are below the AWQC, surface water remediation is not required for
protection of human health and/or the environment.
7.0
Summary of Site Risks
CERCLA directs tnat the Agency must protect human health and the
environment from current and potential exposure to hazardous
substances at superfund sites. In order to assess the current and
potential risks for the 62nd Street Site, a risk assessment was
conducted as part of the Feasibility Study. This section summarizes
the findings concerning the risks from exposure to soil and
groundwater related to the site.
7.1
Identification of the Contaminants of Concern
The 62nd Street site is a threat due to the presence of antimony,
arsenic, cadmium, chromium, copper, lead, "nickel,
bis(2-ethyhexyl)phthalate, and polychlorinated biphenyls (PCBs) in
the soil. Wastes buried at the site fall into two categories: auto
part/battery wastes and cement wastes. The auto part/battery wastes
are highly contaminated, with lead being the most prominent "
contaminant. The cement wastes contain only low levels of
contaminants.
The toxicity, mobility, and persistent characteristics of these
contaminants at the site do not warrant the exclusion of any of
these substances from consideration as chemicals of concern at this
site. The contaminants of concern for this site are listed in Table
7-1. This table also presents the detected range for these
substances, as well as the frequency and media.
7.2 Exposure Assessment Summary
" "',
The princi~al potential pathways of exposure for the 62nd Street
Site are direct contact with contaminated soils or sediments and/or
groundwater consumption and inhalation of contaminated dust. The
key to identifying potential receptors is knowledge of the local
environment surrounding the site. The 62nd Street Site is bound on
the west by fish ponds and a marshy area, on the south by an
automobile junk yard, on the east by private homes and on the north
by a large lake. All residents in the area receive water via
groundwater wells, with two-thirds of the population served by
community and public water supply systems. Approximately 9,000
people are served by private wells within a three-mile radius of the
site. Four current exposure scenarios and four future exposure
scenarios were evaluated in the risk assessment and are listed
below:
-18-
-------
CON'l'A11INANTS OF CONCBRN
62nd Street S~te
----------------------------1------------------1-----------------1-------------------------------1-----------
I Soil I I Concent=at~on Range I Fc,,-;'_ec:';
I Bac)(gl:"ound Range I Media I Sod I 'o/atel:" I o~ ?:s_c_,..
I (:1\g/)(g) I I (:-,g/)(gl I l:1\g/:.) I I::ec.c'=_='-d'-'
----------------------------1------------------1----------------1---------------[---------------1-----------------
I I I I t
I 2 - 10 I TeB t Pit I O. 14 - 512 I I
I . I Test BOl:"ing I BDL I I
I I Sediment I BDL I I
I I Groundwater I ! 0.064 - 0.076 I
I I I I I
I I 1 I I
I 1 - 50 I Surficial Soil I 2.5 - 7.5 I I
I I Tea t Pit I 0 . 084 - 30 I I
I I Te8t Boring I 2.5 - 72 I I
I I Sediment' 0.29 - 4.5 I I
I I Groundwater I 10.0008 0.02561
I I I I I
I I I I I
B~s(2-ethylhexyllphthalate I I Surficial Soil I 0.270 - 0.340 I I
I I Tn t Pi t I 0 . 660 - 91 I I
I I Tnt BOrin.. I 4.1 - 860 I I
I I Sediment I 0.034 - 0.360 I I
I I I I I
I I I I I
I 0.01 - 0.7 I Surficial Soil I 0.17 - 30 I I
I I Te.t Pit I 0.01 - 49 I I
I I Tnt BOrin.. I 0.33 - 35 I I
I I Sediment I 0.5 - 0.82 I I
I I Groundwater I 10.0027 - 0.012 I
I I I. I I
I I I I I
I 1 - 1,000 I Surficial Soil I 3 - 210 I I
I I T..t Pit I 0.13 -140 I I
I I T..t BOrin.. I 3.5 - 79 I I
I I SediJDen t I 3 - 3. 4 I I
I I Groundwater I 10.010 - 0.687 I
I I I I I
I I I I I
I 2 - 100 I Surticial 50i1 I 5.3 - 25,000 I 1
I I Te.t Pit I 0.15 - 43,000 I I
I I T.at Borin9 I 1.7 - 930 I I
I I Sediment I 1.6 - 27.3 I I
I I GroundWater I I 0.010 - 0.217 I
I I I I 1
I I I I I
I 2 - 200 I Surficial Soil I 59 - 2,300 1 [
I I Te.t Pit I 0.05 - 20,000 I I
I I Tnt BOrin.. I Sl - 11,000 I [
I I Sediment I 1.8-162 I I
I I GroundWater I 10.0019 - O.lel I
I I [ I I
TABLE 7-1
C"n::~'!1J.nant
A.~:::-."or.y
.\rsen~c
Cadmium
Chroraium
Copper
Lead
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-------
USLB '-1
(continued)
CONTAMINANTS OF CONCERN
62r.d Street Site
----------------------------1------------------1----------------1-------------------------------1-----------------
I Soil I 1 Concentration Ranqe I Freq"~e:':::7
I Background Range I Hedia I Soil I Water 1 of Po9~:~7e
I (mg/lcg) I I (mq/lcq) I (mg/l) 1 Identi!i=a:~::~.9
----------------------------1------------------/----------------1---------------1---------------1-----------------
I 1 I I I
I I Test Pit 10.1-2601 1
1 I Test Borinq I BOL I I
I 1 Sed.i..:nent I 3.6 - 38.8 I I
1 1 Groundwater 1 I 0.009 - 0.395 I
I 1 I I I
I I I I I
I I Test Pit I 3.8 I I
1 I Sediment I BOL I I
I I I I 1
I 1 I I I
I I Test Boring 1 0.200 - 11.0 I 1
1 I Sediment I BOL I I
I I I I I
I I I I I
I I Test Boring I 6.2 - 9.0 I I
I I I I I
I I I I I
I I Surficial SOU I 0.090 - 2.9 I I
I I Te8t Pit I 0.580 - 20.0 I I
I I Sediment I BDL I I
I I I I I
Cont4l1linant
Niclcel
PCB-10lo
PCB-1242
PCB-1254
PCB-1260
"
"'>,.
-20-
8/:5
0/2
2/ :0
12/ :6
1/:5
0/:')
2/8
0110
2/8
2/4
4/ 15
0/:0
-------
Current Exposure Scenarios:
1.
Direct contact with surficial soils and test pit waste soil
by trespassers and onsite workers.
2 .
Ingestion of groundwater.
3.
Inhalation of contaminants by nearby residents and onsite
workers'.
4 .
Direct contact with sediments by children trespassing
onsite.
Although the future scenarios do not reflect current site
conditions, these scenarios could potentially result from
unrestricted site access.
Future Exposure Scenarios:
1.
Direct contact with surficial soil and subsurface soil by
construction workers and future residents.
2.
3.
Ingestion of groundwater.
Inhalation of contaminants by onsite workers and future
residents.
4 .
Leaching of soil constituents into groundwater.
The direct contact pathway with surface soils and waste pits was
characterized for the following receptors: children ages 6-12
trespassing onsite, adolescents 12-18 years trespassing onsite,
adults trespassing onsite and construction workers. For the future
use, the two scenarios that were quantified were for direct contact
with surficial soils and sediments by onsite workers or future
residents.
The risks associated with the ingestion of contaminated groundwater
was not quantified because the contaminants of concern have MCLs and
therefore, the groundwater will be remediated to the concentrations
required by these drinking water standards, with the exception of
lead.
The current MCL of 0.05 mg/L for lead was promulgated as an interim
drinking water regulation in 1975. Since that time, considerable
human health information has been produced that indicates that this
level may not be protective for young children.
The Agency proposed in 1988 a lead MCL of 0.005 mg/L (the practical
quantitation level) for water entering a distribution system and is
now considering a Maximum Contaminant Limit Goal (MCLG) of zero for
lead in drinking water. In consideration of this information, the
-21-
-------
I
,
I.
I
lead remediation level for groundwater (Class II) at this site is
set below .the current MCL of 0.05 mg/L at a level of 0.015 mg/L.
Appendix C contains a memorandum that supports the 0.015 mg/L as
protective to human health and the environment.
Inhalation of contaminants is considered to be a completed pathway
for onsite workers and nearby residents (ages 6-12 years) for both
the current and f~ture use scenario. The risk associated with the
direct contact with contaminated sediments at the site is quantified
for children ages 6-12 years and for children ages 12-18 years.
The exposure assumptions for these scenarios are summarized in
Tables 7-2 and Table 7-3. The exposure point concentrations used to
determine daily contaminant intake levels are contained in Tables
7-4, 7-5, and 7-6.
7.3 Summary of the Toxicity' Assessment of the Contaminants of
Concern .
To assess the possible toxicological effects from exposure, health
effects criteria are derived from a review of health and
environmental standards and published toxicological studies.
For risk assessment purposes, individual pollutants are separated
into two categories of chemical toxicity, depending on whether they
exhibit carcinogenic or noncarcinogenic effects. This distinction
relates to the current scientific opinion that the mechanism of
action for each category is different.
Carcinogens a
Cancer potency factors (CPFs) have been developed by EPA's
Carcinogenic Assessment Group for estimating excess lifetime cancer
risks associated with exposure to potentially carcinogenic 1
chemicals. CPFs, which are expressed in units of (mg/kg-day)- ,
are multipl~ed by the estimated intake of a potential carcinogen, in
mg/kg-day,'~o provide an upper-bound estimate of the excess lifetime
cancer risk associated with exposure at that intake level. The term
"upper bound" reflects the conservative estimate of the risks
calculated from the CPF. Use of this approach makes underestimation
of the actual cancer risk highly unlikely. Cancer potency factors
are derived from the results of human epidemiological studies or
chronic animal bioassays to which animal-to-human extrapolation and
uncertainty factors have been applied. The cancer potency factors
for the carcinogenic indicator chemicals at the 62nd Street Site are
presented in Table 7-7.
Non-carcinogens:
Reference doses (RfDS) have been developed by EPA for indicating the
potential for adverse health effects from exposure to chemicals
exhibiting noncarcinogenic effects. RfDs, which are expressed in
-22-
-------
Table 1-2
Exposure Assumptions For The Direct Contact
With Surficial Soil and Test Pit Waste Solla
Parameter
b
Children (6-12)
,.verage/Maximum
Adult
Average/Maximum
Workerc
Aver age/Max imum
Body Weight (kg)
Llfet ime (yr)
Exposure Events (d/yr)
Exposure Duration (yr)
Soil Ingestion Rate (g)
Soil Contact Rate
Organics Absorbed Dermally (\)
Inorganics Absorbed Dermally (')
Bioavai labil it y
40/40
70/70
20/36
6/6
50/100
0.4/1.9
10/10
1/1
100/100
70/70
70/70
20/36
5/10
50/100
0.4/1.9
10/10
1/1
100/100
70/70
70/70
240/240
5/10
50/100
0.4/1.9
10/10
1/1
100/100
I
,~
GJ
I
a
The exposure assumptions are the same for the direct contact with sediments exposure pathway except
for the dermal absorption rate. The sediment absorption rate is 3\ for metals and 30\ for organics.
b
With the exception of body weight the exposure asumptions are the sarne for children in the age group
12-18 years. The body weight used for this age group is 55 kg.
c
The exposure assumptions for current exposure to surficial soils were also used for future worker
exposure to subsurface soi16.
-------
Table 7-3
Exposure Assumptions
For The Inhalation Of Surficial Soils
Parameter Workers Residents (Adults)
/ Average/Maximum Average/Maximum
/
/
Body Weight (kg) 70/70 70/70a
Lifetime (yr) 70/70 70/70
Inhalation Rate (m3/day) 20/20 20/20
Respirable Fraction
of Particles (') 25/25 25/25
Bxposure Duration
for Carcinogens (hr) 9600/19200 1400/4800
Exposure Duration for
Noncarcinogens (hr) 1920/1920 160/160
Particulate Concentration
in Air (ug/m3) 50/150 50/150
I
1'->
-I'-
I
a
Body weight of 40 kg was used for the exposure scenario for children (ages
6-12). The other assumptions are the same for children and adult residents.
-------
Table 7.4
Soil Concentrations (mg/kg)
For Direct Contact Scenarios
Surficial Soil Subsurface
Mean Maximum Mean Maximum
carcinoqens
Bis(2-ethylhexyl)
phthalate 3.3 91 28.4 860
PCBs 2.8 20 1.18 11
Arsenica 1.64 12
Noncarcinoqens
I At' b 14.6 512
1-> n 1mony
Vl Bis(2-ethylhexyl)
I
phthalate 3.3 91 28.4 860
Cadmium 2.1 49 2.19 35
Chromium 21.7 210 20.49 210
Copper 361.9 10,000 34.8 25,000
Lead 538.1 20,000 252.9 11,000
Nickelb 43.3 260
a
Arsenic was not detected above background in the surficial 80ils.
b
Antimony and lead were not detected in the subsurface soils.
-------
I
N
0-
I
Table 7.5
Particulate Contaminant Concentrations (ug/g)
For The Inhalation Scenarios
/'
Surficial Soils
Mean Maximum
Subsurface
Mean Max imum
CarcinoQens
Arsenic
Cadmium
Chromium
4.6
1.7
11.9
7.5
30
210 .
7.64 72
2.79 35
20.49 210
34.8 25,000
252.9 11 , 000
NoncarcinoQens
Copper
Lead
104.4
219
25,000
2300
-------
Table 1.6
Sediment Concentrations (mgjkg)
For Direct Contact Scenarios
CarcinOQens Mean Maximum
Arsenic 0.0045 0.0045
Bis(2-ethylhexyl)
phthalate 0.079 0.360
NoncarcinoQens
Bis(2-ethylhexyl)
phthalate 0.079 0.360
Cadimum 0.00053 0.00053
I Chromium 0.0032 0.0034
rv Copper 0.0204 0.027
- J
I LE!ad 0.011 0.162
-------
TAUI.E 7-]
CIIITICAL 1UIICITY VAUIE!; rOR nlf:IUCALS or CVHCEIIH
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-------
units of mg/kg-day, are estimates of lifetime daily exposure levels
for humans, including sensitive individuals. Estimated intakes of
chemicals from environmental media (e.g., the amount of a chemical
ingested from contaminated drinking water) can be compared to the
RfD. RfDs are derived from human epidemiological studies or animal
studies to which uncertainty factors have been applied (e.g., to
account for the use of animal data to predict effects on humans).
These uncertainty factors help ensure that the RfDs will not
underestimate the potential for adverse noncarcinogenic effects to
occur. The RfDs for the noncarcinogenic indicator chemicals at the
62nd Street Site are presented in Table 7-7.
7.4
Characterization of Risk
A characterization of risk was performed in the risk assessment to
address potential risk and hazards to human health posed by the 62nd
Street Site in the absence of remedial action. The risk
characterization is based on identifying potential chemicals of
concern and developing exposure scenarios for each of the potential
and future exposure pathways.
Excess lifetime cancer risks are determined by multiplying the
intake level with the cancer potency factor. These risks are
probabilitieg that are generally expressed in scientific notation
(e.g. 1x10- or 1E-6). An excess lifetime cancer risk of
1x10-6 indicates that, as a plausible upper bound, an individual
has a one in one million chance of developing cancer as a result of
site-related exposure to a carcinogen over a 70-year lifetime under
the specific exposure conditions at a site.
Potential concern for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the hazard quotient
(HQ) (or the ratio of the estimated intake derived from the
contaminant concentration in a given medium to the contaminant's
reference dose). By adding the HQs for all contaminants within a
medium or across all media to which a giver population may
reasonably be exposed, the Hazard Index (HI) can be generated. The
HI provides a useful reference point for gauging the potential
significance of multiple contaminant exposures within a single
medium or across media.
Cleanup levels were derived for those scenarios which, based on the
quantitative risk assessment, may adversely impact the health of
exposed individuals. The exposure pathways which were evaluated and
det~rmined to pose either potential carcinogenic risks greater than
10- and/or a hazard index exceeding one are listed below:
o
Direct contact by workers, children and adult trespassers
with contaminated soil under current scenarios.
o
Direct contact by workers and future residents with
contaminated soil under future use scenarios.
-29-
-------
Table 7.8
Risk Characterization For Direct Contact
With Surficial Soils And Test Pits (Current Use)
Chemical Children / Children Adult Worker
(6-12 yr) / (12-18 yr)
/
Average Maximum Average Maximum Average Maximum Average Maximum
Risk Level
CarcinoQens 2. 3xlO-ll J.8xlO-9 1.7xlO-ll 2.8xlO-9 1. 2x10-11 3.6x10-9 1. 4xlO-10 2.4xlO-8
Bis(2-ethylhexyl)
phthalate 2.2xlO-7 9.4x10-6 7.2xlO-7 6.8xlO-6. 1.lxlO-7 9.2xlO-6 1.3xlO-6 6.0xlO-S
PCBs
CDI : RfD
I
..,.J
:=>
I
NoncarcinoQens 2.8xlO-3 3.8x10-1 2. lx10-3 2.8xlO-1 1.SxlO-3 2.2xlO-1 1. 9xlO-2 1.4x100
Antimony
Bis(2-ethylhexyl) 2.1xlO-S 3.3x10-J 1.Sx10-S 2.4x10-3 1.2x10-S 1. 9xlO-3 1. 4xlO-4 1.2xlO-2
phthalate 4.0xlO-4 2.8xlO-2 2.8x10-4 2.2x10-2 2.4xlO-4 1.6xlO-2 2.8x10-3 1.lx10-l
Cadmium
Chromium 3.2xlO-4 1.2x10-2 2.4x10-4 9.0xlO-3 1. 8xlO-4 7.2x10-3 2.2x10-3 4.8xlO-2
Copper 7.3x10-4 S.4x10-1 S.4x10-4 4.lx10-1 4.1xlO-4 3.2x10-1 4.9xlO-3 2.lx100
Lead 2.9x10-2 4.lx100 2.lxlO-2 3.1x100 1.6xlO-2 2.4xlOO 1. 9xlO-l 1.6xlO+l
Nickel 3.4xlO-4 -3 2.4xlO-4 S.6x10-3 1.8xlO-4 4.4xlO-3 2.2xlO-3 2.9x10-2
7.6x10
-------
Table 7.9
Risk Characterization For Direct Contact
With Surficial And Subsurface Soils (Future Use)
Chemical Worker Resident
Average Maximum Average Maximum
Carcinogens Risk Level
Arsenic 5.0xlO-7 2.2xlO-5 9.7xlO-7 6.7xlO-5
Bis(2-ethylhexyl phthalate) 1.2xlO-9 2.3xlO-7 2.3xlO-9 7.5xlO-7
PCBs 8.5xlO-7 3.3xlO-5 1.6xlO-6 1.lxlO-4
Noncarcinogens CDI:RfD
I
GJ ---
Bis(2-ethylhexyl phthalate) 1. 2x10-3 1. 2xlO-l 1. 3xlO-3 1.3xlO-l
Cadmium 2.8xlO-3 7.8xlO-2 3.0xlO-3 B.6xlO-2
Chromium 2.0xlO-3 4.8xlO-2 2.2xlO-3 5.0xlO-2
Copper 4.6x10-4 7.6xlO-l 4.9xlO-4 8.lxl0-1
Lead 9.3x10-2 8.6xlOO 1. Oxl0-1 9.3xlOO
-------
Table 1.10
Risk Characterization For Inhalation
Of Surficial Soils (Current Use)
./
/
Chemical WOrker / Adult Residents Children Residents
Average Maximum Average Maximum Average Maximum
Carcinogens Risk Level
Arsenic 1.3xlO-8 1. 3xlO-7 . 2.0xlO-9 3.lxlO-8 8.3xlO-lO 1.4xlO-8
Cadmium 5.8xlO-10 6.1xlO-8 8.7xlO-ll. 1.5xlO-8 3. 1xlO-ll 6.8xlO-9
Chromium 4.lxlO-8 2.9xlO-6 5.7xlO-9 7.2xlO-7 2.6xlO-9 3.2xlO-7
Noncarcinogens CDI:RfD
I
w 8.1xlO-6 5.8xlO-3 . 4.9xlO-4 3.0xlO-7
N Copper 6.8xlO-7 2.2xlO-4
I
Lead 4.0xlO-4 1. 3xlO-2 3.3xlO-5 1.OxlO-3 1.5xlO-5 4.6xlO-4
-------
Table 7-11
Risk Characterization For Inhalation
Of Surficial And Subsurface Soils (Future Use)
Chemical Adult Resident Child Resident
Average Maximum Average Maximum
Carcinogen Risk Level
Arsenic 3. 2xlO-9 3.0xIO-7 1. 4x10-9 1.3xIO-7
Cadmium 1. bIO-IO I.BxlO-8 6.lxlO-ll 7.9xlO-9
Chromium -9 7.2xIO-7 3.0xIO-9 3.2xlO-7
7.0x10
Noncarcinogen CDI:RfD
I Copper 2.3xIO-1 4.9xlO-4 1.0x10-1 2.2xIO-4
"" 3.8xIO-5 5. OxlO-3 1.7xIO-5 2.2xlO-3
"" Lead
I
-------
Table 7-12
Risk Characterization For Direct Contact
With Pond Sediments
/
/
Chemical Chi:J:'dren (6-12 yr) Children (12-1B yr)
Average Maximum Average Maximum
Carcinogens Risk Level
Arsenic 1.lx10-11 9. BxlO-ll B.3x10-12 7. OxlO-ll
Bis(2-ethylhexyl) 7. Sx10-13 2.9x10-11 S.SxlO-13 3.6xlO-12
phthalate
Noncarcinogens CDI:RfD
I
w Bis(2-ethylhexyl) 6.Sx10-7 2.6xlO-S 4.7x10-7 1.9xlO-S
p.
I phthalate
Cadmium 1. 7x10-B 1. SxlO-7 1. 3x10-B 1.lx10-7
Chromium 1.lx10-B 9.6x10-B 7.6x10-9 6.Bx10-B
Copper 9. 2xlO-9 1.0xlO-7 6.SxlO-9 7.6x10-B
Lead 1. 3xlO-7 1.6xlO-S 9.3x10-B 1.2x10-S
-------
Inhalation by workers onsite under the current use scenario
and by future residents living onsite.
The risk characterization information is summarized in Tables 7-8
through 7-12.
o
Actual or threatened releases of hazardous substances from this
site, if not addr~ssed by implementing the response action selected
in this ROD, may present an imminent and substantial endangerment to
public health, welfare, or the environment.
7.5
Environmental Risks
Potential environmental effects may occur from contaminants observed
in the surface waters in the ponds located onsite. However, these
ponds only contain water on an intermittent basis. Because limited
information was available on the presence of flora and fauna, an
assessment of impact was performed by comparing concentrations
detected in the surface waters to ambient water quality criteria
(AWQC) for acute and chronic effects to freshwater organisms. Lead,
iron, and zinc were detected above their AWQC in onsite ponds during
the 1986 Remedial Investigation.
The surface water in the offsite ponds showed no contaminants above
the AWQC and are therefore not expected to have any adverse
environmental effects.
There is currently no information to indicate that the Site is
visited or contains any endangered or threatened species.
8.0
Description of Remedial Action Alternatives
The Feasibility Study report presents the results of a detailed
analysis conducted on eight potential remedial action alternatives
for the 62nd Street site. This section of the Record of Decision
presents a summary of each of the eight alternatives that are
described in the FS report.
8.1
Alternative 1 - No Action
The No Action alternative is required by the National Contingency
Plan (NCP) to be considered through the detailed analysis. It
provides a baseline for comparison of other alternatives. Under the
No Action alternative, no source control remedial measures would be
undertaken at the 62nd Street Site.
Given the presence of the contaminant source and the low solubility
of the indicator chemicals at the site, natural soil flushing would
not be expected to reduce soil contaminant levels below cleanup
goals.
-35-
-------
As part of the No Action alternative, groundwater monitoring using
15 existing wells would be conducted to observe changes in the
groundwater quality. Since construction would not be involved in
this alternative, theimplementability concerns, engineering,
equipment and materials, health and safety, and schedule are not
applicable.
The No Action al~ernative would not eliminate any exposure pathways
or reduce the level of risk. The risk assessment identified that
direct contact of soils under a current trespassing or future w~rker
use scenario would result in lifetime cancer risk exceeding 10- .
Additionally, contaminant leaching to groundwater would continue,
thereby exceeding Applicable or Relevant and Appropriate
Requirements (ARARs) and cleanup goals.
Groundwater monitoring would be conducted to observe any changes in
offsite contaminant migration and loading. Cost estimates are based
on quarterly sampling and analyses of 15 .monitor wells for the first
year and annual sampling thereafter. A 30-year time period is used
for comparative purposes.
The estimated present worth cost of this alternative is
approximately $220 thousand, which is based on sampling and
analytical costs for long-term monitoring. Capital costs are not
included with the No Action alternative.
8.2
Alternative 2 - Excavation of Soil and Placement in New Onsite
. Landfill With Groundwater Extraction and Onsite Treatment
This alternative would involve excavating soils and placing them
into a new landfill constructed onsite in accordance with FDER
regulations, in addition to groundwater extraction and onsite
treatment.
The excavation and placement into a new landfill, or encapsulation
cell, woulQ. .be accomplished in a two-phased approach. The Site
would be divided into two portions: the north parcel and the south
parcel (see Figure 8-1). The north and south parcels contain
approximately 38,000 and 55,000 cubic yards of contaminated soil to
be excavated, respectively.
During Phase I, the contaminated soil in the south parcel would be
excavated and transported to the north parcel where it would be
placed on top of the existing contaminated soil. This would leave
the south parcel available for construction of the southern portion
of the new landfill. After the south parcel is prepared and ready
to receive waste, approximately 75 percent of the total contaminated
soil (70,000 cubic yards) would be excavated and loaded into trucks
and transported to the south parcel. Finally, .the south portion of
the landfill would be closed.
-36-
-------
I '
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~ [::J
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8
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62nd
STREET
SITE
~
-~-
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50 0 ~,~
~'-'
po- '"""""
SCALE IN r::~
t:i
w
~
~
en
~
c
~
CO
LEGEND
r771 AREAS TO 8E
~ EXCA\lA7E:)
D ARE,AS -;-0 BE
CAPPED (N[H
LANOF'llL)
FIGwRE ~2
CAMP DRESSER &. \1cKEE INC.
SOIL AREAS TO BE EXCAVATED AND CAPPED
DURING CONSTRUCTION OF NEW LANDFtLl
62nd STREET SITE
TAMPA. FLORIDA
2
-3>
8-1
-------
Phase II would consist of placing the rest of the contaminated soil
in the northern most portion of the site, leaving enough space for
the construction of the northern portion of the new landfill.
Approximately 23,000 cubic yards from the southern portion of the
landfill would be mulched and seeded. The total depth of the
landfill would be approximately 15 feet.
A typical cross-section of the proposed surface cap for the new
landfill is presented in Figure 8-2. A minimum of two feet of cover
would be placed over the contaminated soils to provide a foundation
to support the surface cap. This soil cover would be compacted in
6-inch lifts. An impermeable membrane would consist of a 40 mil
HDPE liner underlain by a geotextile fabric to protect the liner
from puncture. A I-foot drainage layer above the liner would be
constructed of sand and the top foot capping would consist of
topsoil to provide a root zone for vegetative growth. In order to
prevent clogging of the sand drainage layer, a filter fabric would
be placed between the sand layer and the top soil. The fabric would
provide a barrier to soil particles sifting into the sand layer.
All the elements of the surface cap, except for the topsoil layer,
would be used for the bottom and sides of the encapsulation cell.
The topsoil would be vegetated to prevent erosion. The cap would
have a minimUm slope of 2 percent. Surface runoff would be directed
through appropriate drainage channels. Precipitation that
percolates through the topsoil would flow laterally through the sand
drainage layer and into the drainage channels. A leachate
collection system would be incorporated with the bottom liner to
remove the leachate impounded on top of the impermeable layer and
convey it to a sump for treatment, if necessary, before'disposal. A
gas collection, or vent, system could also be included in the design
of the landfill. .
Groundwater dewatering would take place prior to soil removal in
order to facilitate the excavation process. The dewatering would
occur by 'means of an extraction drainfield and any supplemental
dewatering'that might be needed. The same drainfield would be used
to extract the contaminated groundwater located onsite. The
drainfield would consist of perimetrical subsurface drains extending
to the bottom of the surficial aquifer which has an average depth of
17.5 feet below land surface (12.5 feet below the water table).
Offsite groundwater extraction would be accomplished by downgradient
pumping wells in the upper aquifer. Recovery would 'be accomplished
at an approximate steady-state rate of 50 gallons per minute (qpm).
Remediation of the upper aquifer is estimated to take two years.
Groundwater contaminants to be remediated at the site are cadmium,
chromium, and lead. Under this alternative, groundwater treatment
consists of chromium reduction, flocculation, sedimentation, and
filtration. Flocculation and sedimentation are necessary to enhance
metal removal, reduce the loading on filtration units, and prevent
excessive backwashinq. As shown in Figure 8-3, the treatment
-38-
-------
27. MINIMUM
SLOPE
--
~..1.1,..I...~
/ .~~~T!-.~I.q~ /
. , ,
TOPSOIL
F A8RIC
CONTAMINA TED
SOIL
CAMP DRESSER & McKEE INC.
CROSS SECTION OF SURFACE CAP
STREET SITE
FIGURE NO
62nd
TAMPA, FLORIDA
8-2
-39-
-------
W!LL
POI N TS
FlOCCULANT/
COAGULANT
STORAGE ck
EOUALIZA nON
TANK
STA TIC
MIXER
CONCENTRA nON
> POTW LIMITA T10NS
". "
" '
" "
'"
PLA TC:
SEPARATOR
REC':JVE:,~EJ
WA rc:~
BOOSTER
PUMP
FIL TI:R
PRESS
CONCENTRA TION
< POTW LIMITA T10NS
-40-
OFFSITE
SLUOGE
OISPOSAL
CAMP DRESSER & McKEE INC.
CONCEPTUAL GROUNDWATER TREATMENT SYSTEM
62nd STREET SITE
TAMPA, FLORIDA
TO SEWER
CONNECT10N
FIGURE NO,
8-3
-------
involves pumping the contaminated groundwater into a mixing tank
where it is rapidly combined with chemicals for pH adjustment.
Following the mixing stage, during which polymer-type flocculants
would be added, the water flows into a plate settler/clarifier,
where the solids-liquid separation occurs. The precipitated sludge
is pumped to a storage tank for subsequent dewatering using a
recessed plate filter press. This filtering removes fine particles
which do not effectively settle out by gravity. The water recovered
from the dewater1ng operation is recycled to the treatment's
influent stream and the concentrated sludge/filter cake is analyzed
and disposed offsite in accordance with RCRA. The treated effluent
from the plate separator, with contaminant concentrations below the
local Publicly Owned Treatment Works (POTW) limitations, will be
discharged to the closest sewer connection (approximately 500 feet
away), which eventually discharges into the local POTW.
Construction of a new landfill would reduce contaminant mobility by
preventing rainfall infiltration and runoff of contaminated surface
soils. However, the waste toxicity and volume would remain
unaffected by this alternative. Leaching to groundwater would be
significantly reduced. By preventing any direct contact of the
contaminant source with the groundwater, the groundwater ARARs
should be met. With respect to permanence, liners are typically
warranted for 20 years, but the serviceable life should extend well
beyond this time frame. While the new landfill does not provide an
ultimate permanent remedy, it should be considered of long duration.
Extraction and treatment of the contaminated groundwater would
reduce contaminant mobility, toxicity, and volume. This alternative
addresses permanent groundwater remediation combined with source
control measures for the soils.
Both short- and long-term groundwater monitoring would be required
for this alternative. For costing purposes, it was assumed that 15
existing monitor wells would be sampled quarterly for the first two
years (short-term monitoring) and annually for 28 years (long-term
monitoring). Samples would be analyzed for cadmium, chromium, and
lead. Air monitoring during excavation and construction activities
would be necessary to ensure that a safe working environment is
maintained and that no threat to the public health or the
environment is created by air emissions from the site. Health and
safety requirements during the implementation of this alternative
would include periodic air monitoring during excavation and
construction, and the use of personal protection equipment by all
personnel at the site. It is assumed that Level D personal
protection would be used with a contingency to upgrade to Level C,
as necessary.
Equipment and personnel decontamination facilities would also be
necessary. A heavy equipment washdown pad would be constructed and
all vehicles would be decontaminated prior to leaving the site.
Wash water would be treated onsite with the groundwater or stored in
drums and removed for offsite treatment.
-~l-
-------
Approximately six months would be required for design and contractor
selection. Soil excavation and construction of the landfill would
require at least two years. Groundwater remediation would also
require about two years. Assuming no delays, this alternative could
be implemented in approximately 4.5 years.
The estimated present worth cost for this alternative is
approximately $13.72 million, including capital costs of $12.35
million and present worth O&M costs over 30 years of $1.37 million.
8.3
Alternative 3 - Excavation of Soil and Offsite Disposal With
Groundwater Extraction and Onsite Treatment
This alternative would involve excavating contaminated soils and
sending them offsite to a RCRA approved landfill, in addition to
groundwater extraction and onsite treatment.
A total of approximately 93,000 cubic yards of contaminated soils
would be excavated and transported to the closet RCRA-approved
landfill for disposal of hazardous wastes. The targeted disposal
facility is located in Emelle, Alabama, approximately 800 miles from
the site. It is estimated that 20-ton dump trucks, which should be
lined and covered during transportation, would be used to transport
the waste.
Groundwater dewatering would take place prior to soil removal in
order to facilitate the excavation process. The onsite dewatering
and offsite groundwater extraction is the same as described in
A,fternative 2.
This alternative virtually eliminates direct contact risk with
contaminated soil. Since the contaminant source is removed from the
site, this alternative would eliminate rainfall infiltration and
contact of. the contaminant .source with groundwater as well as future
leachate'RJ:oduction and contaminant loadings to groundwater.
,. .
This alternative would not comply with the Federal Resource
Conservation and Recovery Act; 40 CFR Part 261; Land Ban. The RCRA
land disposal restrictions ("LOR") require that RCRA hazardous
wastes be treated to BDAT (Best Demonstrate Available Technologies)
Standards prior to offsite disposal.
The estimated present worth cost for this alternative is
approximately $46.38 million, including capital costs of $45.70
million and present worth O&M costs. over 30 years of $0.68 million.
8.4
Alternative 4 - Excavation of Soil and Placement in New Onsite
Landfill With Groundwater Vertical Barrier
This alternative involves excavating contaminated soils and placing
them into a new landfill constructed onsite, together with onsite
-42-
-------
groundwater containment using a vertical barrier. The excavation of
soil and placement in new onsite landfill would be the same as
described in Alternative 2.
Given the sandy soil conditions at the Site, the vertical barrier is
considered an appropriate technique. The purpose of the groundwater
vertical barrier is to prevent contaminant migration by containing
the onsite plume. Figure 8-4 sets out what would be the forecasted
bounds of the vertical barrier around the Site perimeter. The
vertical barrier considered for this alternative would be built
using in situ technology. Fixation of the barrier would be
accomplished using a cement-bentonite mixture. Special design
considerations would be required in light of the corrosiveness of
the groundwater plume. The barrier would extend over a length of
2,200 feet and to a depth of 25 feet.
The vertical barrier would be used in combination with a containment
drainfield that would consist of perimetrical subsurface drains
extending to a depth of 10 feet below land surface (5 feet below the
water table). This drainfield would also be used for dewatering to
facilitate the soil excavation process.
Offsite groundwater extraction would be accomplished by downgradient
pumping wells in the upper aquifer and treated as described in
Alternative 2. The recovery would be accomplished at an approximate
steady-state rate of 35 gpm. Remediation of the upper aquifer is
estimated to take two years.
Construction of a new landfill would reduce contaminant mobility by
preventing rainfall infiltration and runoff of contaminated surface
soils. However, the waste toxicity and volume would remain
unaffected by this alternative. Leachate generation to groundwater
would be significantly reduced but the groundwater ARARs would not
be met. With respect to permanence, liners are typically warranted
for 20 years, but the serviceable life should extend well beyond
this time frame. This alternative does not provide an permanent
remedy. Containment of the plume would not reduce contaminant
mobility, toxicity, and volume in groundwater.
Short- and long-term groundwater monitoring would be the same as
described in Alternative 2.
Health and Safety requirements while implementing this alternative
would be the same as described in Alternative 2.
Approximately six months would be required for the soil remediation
design and contractor selection. Soil excavation and construction
of the landfill would require at least two years. Offsite
groundwater remediation would require about two years and could be
performed during the design, contractor selection, and actual
construction of the groundwater vertical barrier which would require
about 2.5 years. Assuming no delays, this alternative could be
implemented in approximately five years.
-43-
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200
~
!
-
I
c
200
LEGEND
-- - u VERTICAL BARRIER
1
ItJ
S~Lr IN Frrr
62nd
STREET
SITE
CJ DO
Dol
ccJcP
Do
01
o
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;00 UU_U- CJ L - ill [J
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'
-------
The estimated present worth cost of this alternative is $16.49
million, including capital costs of $14.93 million and present worth
O&M costs over 30 years of $1.56 million.
8.5
Alternative 5 - 80il Capping With Offsite Groundwater
Extraction and Onsite Groundwater Containment
This alternative .would involve capping contaminated soils,
addition to groundwater extraction and onsite treatment.
in
The area to be capped consists of the total areal extent of soil
contamination which encompass approximately 5.5 acres.
A minimum of two feet of cover would be placed over the contaminated
soils to provide a foundation to support the surface cap. This soil
cover would be compacted in 6-inch lifts. An impermeable membrane
would consist of a 40 mil HDPE liner underlain by a geotextile
fabric to protect the liner from puncture. A l-foot drainage layer
above the liner would be constructed out of sand and the top foot of
capping would consist of topsoil to provide a root zone for
vegetative growth. In order to prevent clogging of the sand
drainage layer, a filter fabric would be placed between the sand
layer and the top soil particles sifting into the sand lens.
The topsoil would be vegetated to prevent erosion. The cap
have a minimum slope of 2 percent. Surface runoff would be
through appropriate drainage channels. Precipitation that
percolates through the topsoil would flow laterally through
drainage layer and into the drainage channels.
would
directed
the sand
To prevent contact of contaminated materials at the site with the
water table, dewatering would be considered. Long-term dewatering,
over 30 years, would be achieved through the use of subsurface
drains. These drains would extend to the bottom of the surficial
aquifer along the south border and 5 feet below the water table
along the north, east, and west borders.
Groundwater extraction would not begin until the contaminated soils
have been capped. The onsite dewatering and offsite groundwater
extraction would be the same as described in Alternative 2.
This alternative virtually eliminates the direct contact risk with
contaminated soils. Since the surface cap will reduce rainfall
infiltration, future leachate and contaminant loading and thus the
risk to groundwater will also be reduced.
A significant reduction in risk for groundwater exposure would be
achieved. Groundwater would be extracted to meet the established
cleanup goals for the site. Nonetheless, since the source of
contamination has not been addressed, contaminants could continue to
migrate into the groundwater for a long period of time. Heavy
-45-
-------
metals removal, through pretreatment, is anticipated to meet the
POTW limitations. To accurately predict performance, a field pilot
test would be required.
Construction of a surface cap would reduce contaminant mobility by
preventing rainfall infiltration and runoff of contaminated surface
soils. Howeyer, the waste toxicity and volume remain unaffected by
this alternative. Leaching to groundwater would be significantiy
reduced. With r~spect to permanence, liners are typically warranted
for 20 years, but the serviceable life should extend well beyond
this time frame. While the cap would not provide a permanent
remedy, it should be considered of long duration. Extraction and
treatment of the contaminated groundwater would reduce contaminant
mobility, toxicity, and volume in the groundwater. However, this
alternative does not provide permanent groundwater remediation since
the source is not addressed.
Short- and long- term groundwater monitoring would be the same as
described in Alternative 2.
Health and Safety requirements while implementing this alternative
would also be the same as described in Alternative 2.
Approximately six months wouid be required for design and contractor
selection. Construction of the surface cap would require another
six months. Groundwater remediation would require about two years.
Assuming no delays, this alternative could be implemented in
approximately three years.
The estimated present worth cost for this alternative is
approximately $7.02 million, including capital costs of $5.46
million and present worth O&M costs over 30 years of $1.56 million.
8.6
Alternative 6 - Soil Capping With Groundwater Vertical Barrier
, , .
This alter~~tive would involve capping contaminated soils and
groundwater'extraction with onsite treatment. The soil capping
would the same as described in Alternative 5. The groundwater
vertical barrier would be the same as described in Alternative 4.
This alternative virtually would eliminate direct contact risk with
contaminated soils. Since the surface cap would reduce rainfall
infiltration, future leachate and contaminant loadings to
groundwater would also be reduced.
provisions for containing the plume and minimizing horizontal
contaminant migration in the groundwater would be made. Groundwater
contaminant concentrations, however, would not meet the established
cleanup goals for the site. .
Construction of a surface cap would reduce contaminant mobility by
preventing rainfall infiltration and runoff from contaminated
-46-
-------
surface soils. However, the waste toxicity and volume would remain
unaffected by this alternative. Leaching to groundwater would be
significantly reduced. With respect to permanence, liners are
typically warranted for 20 years, but the serviceable life should
extend well beyond this time frame. The cap does not provide a
permanent remedy but should be considered of long duration for
comparative purposes. Containment of the plume would not reduce
contaminant mobility, toxicity, and volume.
Short- and long- term groundwater monitoring would be the same as
described in Alternative 2.
Health and Safety requirements while implementing this alternative
would also be the same as described in Alternative 2.
Approximately six months would be required for design and contractor
selection. Construction of the surface cap would require another
six months. Offsite groundwater remediation would require about two
years and could be performed during the design, contractor
selection, and construction of the groundwater vertical barrier
would require about 2.5 years. Assuming no delays, this alternative
could be implemented in approximately 3.5 years.
The estimated present worth cost for this alternative is
approximately $11.37 million including capital costs of $9.81 and
present worth O&M costs over 30 years of $1.56 million.
8.7
Alternative 7 - Solidification/Stabilization of Soil With
Groundwater Extraction and Onsite Treatment
This alternative involves excavating contaminated soils and treating
them onsite through solidification/stabilization (S/S) in addition
to groundwater extraction and onsite treatment.
Soil S/S involves onsite treatment of contaminated soils with
suitable fixing agents to reduce the toxicity and mobility of the
indicator chemicals. With this alternative, approximately 100,000
cubic yards of contaminated soils would be excavated. Because both
organic (PCBS) and inorganic (antimony, arsenic, cadmium, chromium,
copper, and lead) contaminants are present, a site-specific mixture
of fixing agents would be required to bind the contaminants. The
use of non-toxic, non-hazardous aggregates is important.
Prior to the S/S process, the waste materials would be screened to
remove large objects (e.g., pieces of tires). These large objects
could be removed, crushed and/or ground in order to be solidified.
The contaminated soils would be transported to an onsite cement
batch plant (a pug mill) where they would be mixed with the fixing
agents. The treated soils would be replaced in the excavated
areas. Stabilization would occur once the returned soil/cement
mixing has solidified.
-....;-
-------
L
The soil and solidifying/stabilizing agents would be measured and
loaded into the pug mill on a batch basis. The mixture would be
controlled by measuring the moisture content of the soil and
aggregates in an onsite laboratory and setting the load cell
controlled weight equipment to add the correct dry weight of soil
. and aggregates to. each batch. The load cells and laboratory
equipment would be calibrated to ensure that quality assurance
procedures are maintained. Prior to actual implementation of the
S/S process, a treatability study would be required to determine the
best combinations and proportions of aggregates and soil.
The space requirements for the mobile treatment equipment and
reactors is estimated to be approximately one acre including
storage. Processing rates of 50 to 100 cubic yards per day are
considered typical, but ultimately depend on unit sizing. For
purposes of this analysis, an S/S processing rate of 100 cubic yards
per day has been used. Two feet of clean topsoil would be placed
over the solidified matrix. The entire site would be seeded and
mulched. .
Groundwater dewatering would take place prior to soil removal in
order to facilitate the excavation process. The onsite dewatering
and offsite groundwater extraction would be the same as described in
Alternative 2.
In this alternative, contaminated soils would be treated to levels
below cleanup goals. Consequently, the risk present by direct
contact and leaching to groundwater w~uld be significantly reduced.
A significant reduction in risk for groundwater exposure would be
achieved. Groundwater will be extracted to meet the established
cleanup goals for the site. Heavy metals removal, achieved through
pretreatment, is anticipated to meet the POTW limitations. To
accurately predict performance, a field pilot test of the treatment
system would be required.
" .
Since all',,-cQ~taminated soils would be treated, future leaching to
groundwater~is not expected to exceed ARARs or cleanup goals. With
the use of appropriate binding agents, this technology would reduce
the mobility and toxicity of the contaminants. However, the volume
of the solidified matrix would increase slightly.
"Extraction and treatment of the contaminated groundwater would
reduce contaminant mObility, toxicity, and volume in the
groundwater'. This alternative provides permanent remediation
combined with source control measures for the soils.
Short- and long-term groundwater monitoring is the same as described
in Alternative 2.
Health and Safety requirements while implementing this alternative
would also be the same as described in Alternative 2.
-48-
-------
S/S treatment would be performed at an assumed rate of 100 cubic
yards per day with a total soil remediation time of three years.
Groundwater extraction and remediation would require about two
years. Assuming no delays, this alternative could be implemented in
approximately five years.
The estimated present worth cost for this alternative is
approximately $24.73 million, including capital costs of $24.04
million and present worth O&M costs over 30 years of $690 thousand.
8.8
Alternative 8 - Solidification/Stabilization of Non-Cement
Wastes and Capping of Soil With Groundwater Extraction and
Onsite Treatment
This alternative would involve excavating contaminated non-cement
wastes and treating them onsite through S/S, as well as capping, and
groundwater extraction and onsite treatment.
Soil S/S would involve onsite treatment of non-cement wastes with
suitable fixing agents to reduce the toxicity and mobility of the
indicator chemicals. With this alternative, approximately 45,000
cubic yards of contaminated soils and non-cement wastes would be
excavated. The S/S treatment would be the same as described in
Alternative 7. The entire site (cement and non-cement wastes) would
be capped.
The area to be capped consists of the total areal extent of soil
contamination, which encompasses approximately 5.5 acres. A minimum
of two feet of cover would be placed over the contaminated soils to
provide a foundation to support the surface cap. This soil cover
would be compacted in six-inch lifts. An impermeable membrane would
consist of a 40 mil HDPE liner underlain by a geotextile fabric to
protect the liner from puncture. A l-foot drainage layer above the
liner would be constructed out of sand and the top 1-foot of capping
would consist of topsoil to provide a root zone for vegetation
growth. In order to prevent clogging of the sand drainage layer, a
filter fabric will be placed between the sand layer and the
topsoil. The fabric would provide a barrier to soil particles
sifting into the sand lens.
The topsoil would be vegetated to prevent erosion. The cap would
have a minimum slope of 2 percent. Surface runoff would be directed
through appropriate drainage channels. Precipitation that
percolates through the topsoil would flow laterally through the sand
drainage layer and into the drainage channels. Figure 8-5 presents
the areal extent of partial S/S and total capping.
Groundwater dewatering would take place prior to soil removal in
order to facilitate the excavation process. The onsite dewatering
and offsite groundwater extraction would be the same as described in
Alternative 2.
-49-
-------
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00
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~v
62nd
STREET
SITE
~
1
50 0
.....~.....
SCALE :N F::::T
50
~
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a:::
~
In
~
C
N
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LEGEND
m AREA TO 8E
W SOLIDIFIEiJ/S-;"A8IL:E:
(NON-CEMENi 'NAS7E3;
~ AREA TO Be: CA':PD
+ 100' SOIL C."
FIGURE ,"0,
CAMP DRESSER & McK2E INC.
AREAL EXTENT OF PARTIAL
SOLIDIFICATION/STABILIZATION AND TOTAL CAPPING
62nd STREET SITE'
TAMPA. FLORIDA
-50-'
8-5
-------
In this alternative, non-cement wastes would be treated to levels
below cleanup goals and the the solidified non-cement wastes and the
cement wastes would be capped. Consequently, a direct contact risk
and leaching to groundwater would be significantly reduced.
A significant reduction in risk for groundwater exposure would be
achieved. Groundwater would be extracted to meet the established
cleanup goals for the site. Heavy metals removal, achieved through
pretreatment, is anticipated to meet the POTW limitations. To
accurately predict performance, a field pilot test would be
required.
Since all non-cement wastes are targeted for treatment, future
leaching is not expected to exceed groundwater ARARs or cleanup
goals in these contaminated media. With the use of appropriate
binding agents, this technology would reduce the mobility and
toxicity of the contaminants. However, the volume of the solidified
matrix would increase relative to the original volume of the
non-cement wastes.
Construction of a surface cap would reduce contaminant mobility in
the cement wastes by preventing rainfall infiltration and runoff of
contaminated surface soils. However, the waste toxicity and volume
of the cement waste materials remain unaffected by this
alternative. Leaching to groundwater would be significantly
reduced. With respect to permanence, liners are typically warranted
for 20 years, but the serviceable life should extend well beyond
this timeframe. The cap does not provide a permanent remedy for the
cement waste, however the engineering controls would prov~de
sufficient protectiveness to reduce the risk to below 10- .
Extraction and treatment of the contaminated groundwater would
reduce contaminant mobility, toxicity, and volume in the
groundwater. This alternative would provide permanent remediation
combined with source control measures for the soils.
Short- and long- term groundwater monitoring would be the sarne as
described in Alternative 2.
Health and Safety requirements while implementing this alternative
would be the same as described in Alternative 2.
S/S would be performed at an assumed rate of 100 cubic yards per day
with a total soil remediation time about 1.5 years. Construction of
the surface cap would require about two years. Assuming no delays,
this alternative could be implemented in approximately four years.
The estimated present worth cost for this alternative is
approximately $16.46 million, including capital costs of $15.77
million and present worth O&M costs over 30 years of $690 thousand.
-51-
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9.0
Summary of Comparative Analysis of Alternatives
This section provide the basis for determining which alternative (i)
meets the threshold criteria of overall protection of human health
and the environment and compliance with ARARs, and (ii) provides the
"best balance" between long- term' effectiveness and permanence,
reduction of toxicity, mobility, or volume through treatment, short- .
term effectiveness, implementability, and cost. A glossary of the
evaluation crite~ia is provided in Table 9.1.
9.1
Overall Protection of Human Health and Environment
All of the alternatives, with the exception of the "no action"
alternative, would provide protection of human health and the
environment by eliminating, reducing, or controlling risk through
treatment, engineering controls, or institutional controls. Because
the "no action" alternative offers no reduction in risk to human
health and the environment, it is not considered further in this
analysis as an option for this site.
Alternatives 5 and 6 (soil capping) do not use treatment to reduce
the volume or toxicity of the soil contaminants and require
long-term maintenance to ensure the integrity of the cap.
Alternative 3 (offsite disposal) transfers the risk to another
location without treatment and is the most costly of the soil
alternatives. Alternatives 2 and 4 (new onsite landfill) do not use
treatment to reduce the volume or toxicity of the soil contaminants
and require long-term maintenance.
Alternatives 7 and 8 (solidification/stabilization) offer the
greatest reduction of risk by treating the contaminated soils.
technology has been demonstrated to be effective for metals and
PCBs. .
This
9.2 Comp~i~ce with ARARs
. "'--.
Alternative'3 (offsite disposal) would not comply with the Resource
Conservation and Recovery Act (RCRA) - Land Disposal Restrictions
(LDR). The contaminated soils at the Site would require treatment
prior to disposal which is not provided under Alternative 3.
Alternatives 4 and 6 (groundwater vertical barrier) would not treat
the offsite groundwater plume, thus the MCLs for groundwater would
not be met. Alternatives 2 and 4 (new onsite landfill) and
Alternatives 5 and 6 (capping) would not meet the Superfund
Amendments and Reauthorization Acts (SARAs) preference for
treatment. Only Alternatives 7 and 8 (solidification/stabilization)
would meet all ARARs and SARAs preference for treatment at the 62nd
Street Site.
-52-
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TABLE 9.1
GLOSSARY OF EVALUATION CRITERIA
Overall Protection of Human Health and Environment addresses
whether or not a remedy provides adequate protection and describes
how risks posed' through each pathway are eliminated, reduced, or
controlled through treatment engineering controls or institutional
controls.
ComDliance with ARARs addresses whether or not a remedy will
meet all of the applicable or relevant and appropriate requirements
of other Federal and State environmental statutes and/or provide
grounds for invoking a waiver.
Lonq-Term Effectiveness and Permanence - refers to the magnitude
of residual risk and the ability of a remedy to maintain reliable
protection of human health and the environment over time once
cleanup goals have been met.
Reduction of T oxic itv. Mobilitv. or Volume Throuqh Treatment - is
the anticipated performance of the treatment technologies that may
be employed in a remedy.
Short-Term Effectivenes8 refers to the speed with which the
remedy achieves protection, as well as the remedy's potential to
create adverse impacts on human health and the environment that may
result during the construction and implementation period.
r8DlementabH itv is the technical and
of a remedy, including the availability
needed to implement the chosen solution.
administrative feasibility
of materials and services
Cost - includes capital and operation and maintenance costs.
State Acceotance indicates whether the State
opposes, or has no comment on the Proposed Plan.
concurs
with,
Community AcceDtance - the Responsiveness Summary in the aptJendix
of the Record of Decision reviews the public comments received frc~
the Proposed Plan public meeting.
-53-
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9.3
Long-Term Effectiveness and Permanence
Alternatives 7 and 8 (solidification/stabilization) would provide
the greatest degree of long-term elimination of risk posed by
contaminants at the 62nd Street site because the contaminants are
permanently bound in a cement matrix. Alternatives 2 and 4 (new
onsite landfill) would provide long-term protection to public health
and the environment; however, long-term monitoring would be required
to ensure the integrity on the new landfill. Alternatives 5 and 6
(capping) would leave the contaminants in place without treatment.
The cap's effectiveness would be evaluated through long-term
monitoring. Alternative 3 (offsite disposal) would merely transfer
the risk to another location but would offer some protection by
proper disposal in a permitted hazardous waste facility.
Reduction of Toxicity, Mobility, or Volume of the Contaminants
Through Treatment
Alternatives 7 and 8, (Solidification/stabilization) would provide a
significant reduction of toxicity through treatment of the
contaminated soils. This alternative would also provide protection
to the groundwater by treating the source of contamination.
Solidification would also provide a significant reduction of
contaminant mobility by binding the contaminants into a cement
matrix. Alternatives 2 and 4 (new onsite landfill) and 3 (offsite
disposal) do not provide for a reduction, of toxicity or volume of
the contaminants but would reduce their mobility. Alternatives 5
and 6 (capping) do not reduce toxicity, mobility, or volume of the
contamination.
9.4
9.5
Short-Term Effectiveness
All of the alternatives would immediately break the soil ingestion
exposure pathway. Minimal risk is associated with remedy
construct~o~ for each alternative; however, solidification 'and
offsite disposal would require additional precautionary measures to
ensure the safety of workers. Offsitedisposal adds a slight risk
to the general public due to hauling activities. Given the relative
immobility of site contaminants and the media in which that they are
contained (soil), this risk would be minimal in the event of an
accident during transportation.
9.6
Cost
Alternative 3 (offsite disposal) is the most expensive remediation
alternative at $46.379 million dollars. The cost for Alternatives 2
and 4 are substantially less than the cost for Alternative 3, and
may provide a greater protection. Alternatives 5 and 6 (capping)
are the least costly and provide the least amount of protection.
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Alternatives 7 and 8 (Solidification/stabilization) would provide
the greatest amount of protectiveness, yet alternative 7 cost
considerably more than alternative 8. Alternative 7 cost $24.725
million dollars while alternative 8 cost $16.457 million dollars.
Alternative 7 would solidify the entire site and alternative 8 would
solidify the battery wastes, shredded auto parts, and contaminated
soils. Contaminant levels in the cement wastes represent little
threat through e~ther direct contact or leaching to ground water.
Since these wastes are consolidated and have low permeability, they
are believed to offer a protective degree of immobilization without
treatment of solidification.
9.7
State Acceptance
The State of Florida, as represented by the Florida Department of
Environmental Regulation, concurs in the selection of Alternative 8
as the preferred alternative for the 62nd Street Site.
9.8
Community Acceptance
Based on comments made by citizens at the public meeting held on
March 29, 1990, and those received during the public comment period,
the agency perceives that the community believes the selected remedy
will effectively protect human health and the environment.
10.0
The Selected Remedy
Based upon consideration of the requirements of CERCLA, the detailed
analysis of the alternatives, and public comments, EPA has
determined that Alternative 8 is the most appropriate remedy for the
62nd Street Site in Tampa, Florida.
Under this alternative, battery wastes and shredded auto parts will
be treated by solidification/stabilization and the entire landfill
will be capped. Groundwater in the surficial aquifer exceeding
drinking water standards will be recovered and treated, with
discharge to either a local wastewater treatment plant or to the
Palm River.
This alternative distinguishes between those areas of the site where
cement wastes predominate, and those areas with extensive deposits
of shredded auto parts and battery wastes. The fill material
composed of battery wastes and auto parts will be excavated, treated
by solidification/stabilization and replaced onsite. Approximately
48,000 cubic yards of material are estimated to exceed the cleanup
criteria and will be treated. Solidification/Stabilization is a
widely used treatment that permanently immobilizes contaminants in a
cement-like matrix. Treatment of the battery and auto wastes will
effectively prevent them from posing a threat through direct contact
or by leaching to groundwater.
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I~___-
Contaminant levels in the cement wastes represent little threat
, through either direct contact or leaching to groundwater. Since
these wastes are consolidated and have low permeability, they are
believed to offer a protective degree of immobilization without
treatment or solidification. To further ensure that any threat from
these wastes is minimized, they will be included in the area to be
covered by an impermeable cap. This will provide protection from
exposure by direct contact and will reduce potential leaching of
contaminants by preventing infiltration of rain water.
The goal of this remedial action is to ,restore the surficial
aquifers groundwater to its beneficial use. The recovery and
treatment of groundwater exceeding primary drinking water standards
will protect the surficial aquifer for any future use. This
procedure will also remove the threat posed by potential migration
of contaminants from the surficial aquifer to the Floridan aquifer
through breaches in the intervening clay layer. However, studies
suggest that groundwater extraction and treatment are not, in all
cases, completely successful in reducing contaminants to
health-based levels in the aquifer. EPA recognizes that operation
of the selected extraction and treatment system may indicate the
technical impracticability of reaching health-based ground water
quality standards using this approach. If it becomes apparent,
during implementation or operation of the system, that contaminant
levels have ceased to decline and are remaining constant at levels
higher than the remediation goal, that goal and the remedy may be
reevaluated.
Institutional controls and other land use restrictions will be
to ensure the integrity of the remedy over time and preclude
exposure to treated soils through prohibitions on future uses
Site incompatible with the cap. These institutional controls
additional protection of human health and the environment and
the long-term effectiveness and permanence of the remedy.
The duration of the soil treatment is estimated at two years.
Groundwate,r 'cleanup is also estimated to take two years. Following
completion'of the cleanup, monitoring will be conducted for a
minimum of five years to demonstrate that the cleanup has met the
remediation goals. The total present worth cost of this alternative
is $16,460,000.
used
of the
offer
ensure
10.1
Remediation Goals
The 62nd Street site is a threat due to the presence of antimony,
arsenic, cadmium, chromium, copper, lead and polychlorinated,
biphenyls (PCBs) in soils and groundwater. Wastes buried at the
site fall into two categories; auto part/battery wastes and cement
wastes. The auto part/battery wastes are highly contaminated, with
lead being the most prominent contaminant. The cement wastes
contain only low levels of contaminants.
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Criteria for the cleanup of contaminants in soil are based on
consideration of health effects and leaching to groundwater. For
each contaminant, the most stringent of these two considerations
takes precedence. The health-based cleanup criteria are listed in
Table 10.1.
The presence of groundwater contamination at the site indicates that
leaching of contaminants from waste has occurred. Numerous
uncertainties exist in the determination of cleanup criteria for the
prevention of unacceptable leaching to ground water. Thus a range
of criteria were considered for cadmium, chromium, and lead, the
site contaminants most likely to leach. For the auto part/battery
wastes, the selected criteria are based on the average value of
soil-water partitioning coefficients reported in the literature.
Levels of cadmium, chromium and lead exceeding these criteria are
widely distributed in the auto part/battery wastes.
Leachinq-based cleanup criteria for auto part/battery wastes
cadmium
chromium
lead
ranqe (ppm)
0.065 - 1.4
0.23 - 400
0.87 - 1300
selected
0.3
9
17
(ppm)
Due to characteristic low permeability of the cement wastes,
different criteria are appropriate for leaching of contaminants from
this area of the site. Leaching of contaminants is inhibited by the
high pH of the wastes through the extensive formation of insoluble
metal hydroxides. In addition, the low permeability of these wastes
retards migration of any mobile form of these contaminants. Since
these contaminants are known to be ten to one hundred times less
leachable at the high pH characteristic of the cement wastes, the
leaching-based cleanup criteria selected for these wastes are ten
times higher than those proposed for the other wastes.
Leachinq-based cleanup criteria for the cement wastes
cadmium
chromium
lead
criterion
3
90
170
(ppm)
Groundwater
Health based cleanup levels were not derived for groundwater because
ARARs were available. The surficial aquifer has concentrations of
lead, cadmium, and chromium that exceed the Federal and State
primary drinking water standards. The cleanup criteria for cadmium,
and chromium in the surficial aquifer will be the Maximum
Concentration Limits (MCLs). As discussed in Section 7.2, a
concentration on lead of 15 ppb is protective of drinking water.
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TA'BL:: 10-1
SIT=: CF.E:1IC.:u.S EXa:::::D!NG CU:~"ltl? C...:JALS
62:-,d STI\E!'I' SITE'
'!.~'1PA, FLCR!DA
CCNTA"1INA~
!'!ED'HiM
C:€1!c.u
N;?-.
Surface Water:
Ncne above ~~~Cs
Seci;nent
Ncne atcve Risk-Eased Levels
Soil
Anti:nony
Arsenic
Cadmi urn
Chr:cmium
C::~ge:
lead
PCBs
Gr:our.o..rat.er:
CadmiUm
Ch:omium
lead
c!'E;..~.'t;p C~
89
3.5
0.315
8.8
8,260
17.4
0.33
10
50
15
N/A
mg/1
-------
11. 0
Statutory Requirement
The U.S. EPA and FDER believe that this remedy will satisfy the
statutory requirements of providing protection of human health and
the environment, attaining applicable or relevant and appropriate
requirements of other environmental statutes, will be
cost-effective, and will utilize permanent solutions and alternative
treatment technologies or resource recovery technologies to the
maximum extent practicable. Sections 11.1 thru 11.5 below, are the
statutory requirements for this site.
11. 1
Protection of Human Health and the Environment
The selected remedy provides protection of human health for future
users through extraction and treatment of contaminated groundwater
and treatment of contaminated soils. The aquifer restoration will
prevent the public from ingestion of contaminant concentrations in
the water. It is estimated that the groundwater will be restored to
MCLs or health-based risk levels in two years.
In addition, the remedy will prevent the ingestion Os contaminated
soil posing an undue risk of cancer greater than 10-. The
potential leaching from the soil into the groundwater will be
adequately reduced to protect human health and the environment. It
is estimated that the soils will be treated in two years.
11.2
Attainment of the Applicable or Relevant and Appropriate
Requirements (ARAR)
Remedial actions performed under CERCLA must comply with all
applicable or relevant and appropriate requirements (ARARs). All
alternatives considered for the 62nd Street site were evaluated on
the basis of the degree to which they complied with these
requirements. The selected remedy was found to meet or exceed the
following ARARs, as discussed below.
FEDERAL REGULATIONS:
Resource Conservation and Recoverv Act
40 C.F.R. Part 264 Subpart X - Miscellaneous Treatment Unit
40 C.F.R. Part 261 Land Ban - The RCRA land disposal
restrictions ("LDR") (40 CFR 268) promulgated in the 1984 HSWA
amendments require that RCRA hazardous wastes be treated to BDAT
(Best Demonstrated Available Technologies) Standards prior to
placement into the land. EPA is promulgating treatment
standards for RCRA wastes in a phased approach, with the last
treatment standard to be promulgated in May 1990. The onsite
wastes are characterized as RCRA wastes for lead, because it
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exhibit EP Toxicity as defined 40 CFR 261. Excavation and
treatment in a separate unit is considered to be placement under
RCRA LDR. Therefore, LDR will be an applicable/or relevant and
appropriate requirement. The selected remedy will meet BDAT
standards for RCRA characteristic waste. The treatment 'process
will Lmmobilize the metals to the extent that the waste will no
longer be hazardous waste as defined by RCRA.
40 C.F.R. Part 264 Subpart G - Closure and Postclosure
Clean Water Act/Safe Drinkina Water Act
EPA's determination of appropriate groundwater cleanup criteria
involved an evaluation of contaminant concentrations relative to
available health-baseq .standards. Such limits, including Maximum
Concentration Limits (MCLs) and Maximum Concentration Limit Goals.
(MCLGs), and Federal Ambient Water Quality Criteria (AWQC), Section
304 of the Clean Water Act (CWA) used as prescribed in Section
121(d)(2)(b)(i) of CERCLA, as defined by the Safe D~inking Water Act
(SDWA) (40 CFR Part 141 and 142) and the Clean Water Act,
respectively, will be met at this site.
Federal Clean Air Act
The Clean Air Act (CAA) identifies and regulates pollutants that
could be released during earth-moving activities associated with the
excavation of soils on-site. The CAA Section 109 outlines the
. criteria pollutants for which National Ambient Air Quality Standards
have been established. CAA Section 112 identifies pollutants for
which there are no applicable Ambient Air Quality Standards, those
substances regulated under the Federal National Emission Standards
for Hazardous Pollutants. The CAA is an ARAR and the regulatory
standards of the CAA will be complied with during implementation of
. the remedy. . .
Toxic Substances Control Act (TSCA)
"',- "..
" '
40 CFR Par~' 761, promulgated under the authority of TSCA,
establishes criteria to determine adequacy of cleanup of spills
resulting from release of materials containing PCBs. The 62nd
Street Site would classify as a non-restricted access area. The
requirement for decontaminating PCB spills in a non-restricted
access area is to decontaminate the soil to 10 mg/kg PCBs by weight,
provided the- soils are excavated to a minimum depth of 10 inches.
The excavated soil must be replaced with clean soil which contains
less than 1 mg/kg PCBs. The selected remedy will met the TSCA
requirements.
Endanaered SDecies Act
The selected remedy is prote~tive of species listed as endangered or
threatened under the Endangered Species Act. Requirements of the
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Interagency Section 7 Consultation Process, 50 CFR Part 402, will be
met. The Department of Interior, Fish and Wildlife Service, will be
consulted during remedial design to assure that endangered or
threatened species are not adversely impacted by implementation of
this remedy. There is currently no information to indicate that the
Site is visited or contains any endangered or threatened species.
National Historical Preservation Act (NHPA)
The NHPA requires that action be taken to preserve or recover
historical or archaeological data which might be destroyed as a
result of site activities. There is no information to indicate
the 62nd Street site contains any historic or archaeological
significance.
that
Federal Occupational Safety and Health Administration Act (OSHA)
The selected remedial action contractor will develop and implement a
health and safety program for its workers. All onsite workers will
meet the minimum training and medical monitoring requirements
outlined in 40 CFR 1910.
STATE REGULATIONS:
Florida Administrative Code Chapter 17-3
Water quality standards for surface water and groundwater affected
by leachate and storm runoff from the Site will be met.
Florida Administrative Code Chapter 17-6
Effluent limitations and operating requirements for wastewater
facilities treating landfill leachates will be met.
LOCAL REGULATIONS:
City of Tampa
The City of Tampa has established minimum quality standards for
disposal to the local POTW. The disposal standards for discharge to
the local POTW will be met.
Southwest Plorida Water Manaqement District (SWFWMD)
The Southwest Florida Water Management District will be consulted
during remedial design to assure compliance with surface water
runoff for the Site.
11.3
Cost Effectiveness
EPA's selected remedy (Alternative 8) affords a higher degree of
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overall protectiveness in not only protecting the public against
direct exposure to surface soils but also in removing the threat of
future contamination to the groundwater. The total present worth
cost for the selected remedy is $16,460,000.
This remedy employs a proven technology which can be implement~d
year round and has been proven to be a permanent solution for this
type of contamination. The selected remedy affords overall
effectiveness proportional to its costs such that the remedy
represents a reasonable value for the money. When the relationship
between cost and overall effectiveness of the selected remedy is
viewed in light of the relationship between cost and overall
effectiveness afforded by the other alternatives, the selected
remedy is cost-effective. .
11.4
Utilization of Permanent Solutions and Alternative Treatment
Technology or Resource Recovery Technologies to the Maximum
Extent Practicable
U.s. EPA believes the selected remedy is the most appropriate
cleanup solution for the 62nd Street site and provides the best
balance among the evaluation criteria for the remedial alternatives
evaluated. This remedy provides effective protection in both the
short- and long-term to potential human and environmental receptors,
is readily implemented, and is cost effective.
Solidification/Stabilization of the contaminated battery wastes and
shredded auto parts represents a permanent solution (through
treatment) which will effectively reduce and/or eliminate mobility
of hazardous wastes and hazardous substances into the environment.
11.5
Preference for Treatment as a Principal Element
Treatment of the battery and auto wastes will effectively prevent
them from"posing a threat through direct contact or by leaching to
ground water.
Solidification/Stabilization is a treatment process which has been
demonstrated to" effectively reduce the mobility of heavy metals in
the environment. Therefore, the statutory preference for remedies
that employ treatment as a principal element is satisfied.
11.6
Documentation of Significant Changes
Based upon the requirements of CERCLA section 117(b), EPA has
determined that a significant change has been made to the selected
remedy from the time that it was proposed in the Proposed Plan until
final adoption of the remedy in this Record of Decision. The change
that has occurred is the cleanup level of lead in the groundwater
from the current MCL of 50 ppb to a level of 15 ppb.
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APPENDIX A
Responsiveness Summary
62nd Street Site
Tampa, Hillsborough County, Florida
-------
RESPONS IVENESS SUMMARY
The Florida Department of Environmental Regulation (FDER) and the
U.S. Environmental Protection Agency (EPA) established a public
comment period f~om March 23, 1990 through April 23, 1990 for
interested parties to comment on FDER's and EPA's Proposed Remedial
Action Plan (PRAP) for the 62nd Street Dump site. The comment period
followed a public meeting on March 29, 1990, conducted by FDER and
EPA, held at the Oak Park Community Center in Tampa, Florida. The
meeting presented the results of the studies undertaken and the
preferred remedial alternative for the site.
A responsiveness summary is required by Superfund policy to provide a
summary of citizen comments and concerns about the site, as raised
during the public comment period, and the responses to those
concerns. All comments summarized in this document have been
factored into the final decision of the preferred alternative for
cleanup of the 62nd Street Dump site.
This responsiveness summary for the 62nd Street Dump site is divided
into the following sections.
I.
Overview This section discusses the recommended alternative
for remedial action and the public reaction to this
alternative.
II.
Backaround on Communi tv Involvement and Concerns This
section provides a brief history of community interest and
concerns regarding the 62nd Street Dump site.
III.
SUmmarv of Ma10r Ouestions and Comments Received Durina the
PUblic Comment Period and FDER's or EPA's Resoonses This
section presents both oral and written comments submitted
during the public comment period, and provides the responses
to these comments. .
IV.
Remainina Concerns This section discusses community
concerns that EPA should be aware of in design and
implementation of the remedial alternative for the site.
I.
Overview
The preferred remedial alternative was presented to the public in a
fact sheet released on March 22, 1990 and at a public meeting held on
March 29, 1990. The recommended alternative addresses the source of
the contaminatipn by containing the landfill wastes and treatment of
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the groundwater.
include:
The major components of the recommended alternative
Solidification/Stabilization of the battery wastes and
shredded auto parts.
Capping of the entire site.
The cement wastes onsite represent little threat through
either direct contact or leaching to groundwater; therefore,
they will not be treated.
Extraction and treatment of the groundwater from the
surficial aquifer both onsite and offsite.
The community, in general, favors the selection of the recommended
alternative. However, the community is concerned about the amount of
time required to implement the alternative.
II.
Backqround on Community Involvement and Concern
The Tampa community has been aware of the contamination problem at
the 62nd Street Dump site for several years. FDER distributed the
first fact sheet to the public on January 27, 1986. This fact sheet
contained information pertaining to the upcoming Remedial
Investigation (RI).
FDER and EPA conducted the second public meeting on March 29, 1990.
The purpose of this meeting was to explain the results of the site
studies, to present the recommendations of FDER and EPA for site
cleanup, and to accept questions and comments from the public on any
aspect of the site or its cleanup. At this meeting, the key issues
and concerns identified were:
Groundwater Contamination Concerns: Property owners were
concerned with the levels of contaminants found in the surficial
aquifer. The citizens were also concerned that their private
wells might tap into this aquifer.
Time: The public was concerned with the amount of time that it
will take to clean up the site.
III. SummarY of Major Ouestions and Comments Received Durinq the
Public Comment Period and FDER's or EPA's Responses.
1.) One commenter inquired about the depth of the surficial
aquifer. There was concern that private wells were at surficial
aquifer level.
FDER Response: To the best of FDER knowledge, people do not receive
drinking water from the surficial aquifer. Appreciable levels of
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lead and chromium were found in the lower Floridan Aquifer, but these
levels were well below the drinking water standards.
2.) A commenter inquired what the concentration of lead is in the
surficial aquifer.
FDER Response: The concentration of lead can be as high as 200 parts
per billion in t~e surficial aquifer.
3.) A commenter inquired what the concentration of chromium is in
the surficial aquifer.
FDER Response: Chromium reached concentrations as high as
approximately 600 parts per billion. The dr~nking water standards
for chromium are 50 parts per billion.
4.) Another commenter inquired what level of PCBs are found in the
surficial aquifer.
FDER Response: The highest level of PCBs found in the soil was 20
parts per million.
5.) A commenter stated that his well water did not taste good.
inquired what the contaminants were.
He
EPA Response: The drinking water source for this area is high in
iron and sulfur, which leads to a bad taste, odor, and color.
However, the health department has examined the water quality and has
found no toxic chemicals.
6.) . A commenter expressed concern that the county was not being
responsive to citizens who felt their drinking water was not adequate
for. consumption.
FDER Res~onse: FDER will explore the possibility of providing an
alternate w~ter supply with Hillsborough County.
~ , .
, . .
7.) Another commenter inquired about health effects from
contaminated soil during any implementation of the cleanup.
. FDER Response: primarily any danger that could occur during
construction would be caused by dust emissions blowing offsite.
During Remedial Design (RD), alternatives will be studied to minimize
this problem. There are standard construction methods that are used
to control dust emissions.
8.) A representative from Congressman Sam Gibbons' office inquired
how long after the remedy is selected before the clean-up begins.
EPA Attornev Response: When a Potentialiy Responsible Party(s) (PRP)
is identified, under the statute, clean up design should begin after
120 days. Sometimes it takes longer.
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EPA Response: Once the comment period has ended, which will be April
23rd, EPA will evaluate the comments that are received from the
public. Then, EPA will sign the Record of Decision and begin to
serve notice to the Potentially Responsible Party(s). This notice
will give the PRPs the opportunity to conduct the remedial design and
the remedial action.
If the PRPs negotiate a Consent Decree with EPA, the PRPs will
conduct the desi~n and cleanup. In the event that the PRPs choose
not enter into a Consent Decree with the Agency, EPA will conduct the
design utilizing the Superfund money. Either way, EPA anticipates
to begin the remedial design prior to September 1990.
9.) A cornrnenter inquired if there is either a statutory or
regulatory procedure to expedite this process.
FDER Response: FDER has evaluated the need for Lrnrnediate and
temporary measures; there is no possible temporary, short-term way to
improve the situation.
10.) Another commenter inquired what has FDER been doing up to this
point.
FDER Response: FDER started its investigation in '86 and this public
meeting represents FDER's completion of its part. It has been four
years, and admittedly it should have taken less time.
11.)
Another commenter inquired how much the RI/FS cost.
FDER Response:
The RIfFS costs about $400,000.
12. )
A cornrnenter inquired if PRP negotiations are confidential.
EPA Attorney Response: That would depend on the case and whether or
not the PRP is willing to release certain information.
13.) A commenter noted that there have been no PRPs identified at
this site at present and then inquired how long before clean up will
actually begin.
EPA Response:
Realistically, the cleanup may begin early 1991.
14.) After a discussion as to whether or not viable PRPs could be
identified, one commenter inquired if the cleanup process could be
expedited if citizens filed a class action suit.
EPA Attornev Response: It is certainly a possible alternative.
However, a class action suit may not hasten the process.
15.) After an explanation of how the solidification/stabilization
process works, a cornrnenter wanted to know what would keep the
contaminated cement contained.
-4-
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FDER Response: The treatment itself causes the contaminants to
become immobilized. The treated soil is then impermeable so that
very little groundwater or rain water can percolate through the soil.
16. )
One commenter inquired if the treatment is permanent.
FDER Response:
The treatment is considered to be a permanent remedy.
17.) A commenter inquired as to what depth the waste material
extends.
FDER Response: From the soil borings sampled, waste material has
been found to extend approximately 20 feet from the surface. The
waste lies directly on top of the clay in the Hawthorn Formation.
18.) After a discussion concerning alternatives for cleaning up the
site, a commenter inquired as to which alternative will be chosen for
this project.
FDER Response: The alternative that both EPA and FDER favor at this
time is the last alternative, Nwnber 8. This is where all the debris
is excavated from the auto battery waste portions of the site,
treated by solidification, and returned to'the site. The entire site
would then be covered with an impermeable cap. This process would be
accompanied with recovering treatment of the groundwater in the
surficial aquifer.
19.). A commenter inquired if, after April 23rd, EPA would be
managing the site.
EPA Response: Yes. EPA will take it Federally when the Record of
Decision is written. At that point, EPA will consult the State on
the remedial designs and will consider any input the State may have.
.The following re~ponses are provided to written comments received by
the Agen~y:" .
" '.
20.) The commenter requested access to a copy of the final Record of
Decision (ROD) for the site.
EPA Response: EPA will include a copy of the final ROD in the
Administrative Record which is maintained for public use in the
Special Collections Section at the Tampa Hillsborough County Public
Library, 900: North AShley, Tampa, Florida 33602. .
21.)
site.
The commenter indicated that waste acid had been dumped at the
EPA Response: EPA has no knowledge of or data about waste acid
having been dumped at this site. In fact, the pH of the groundwater
is very basic, with an average pH of 11.5.
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22.) The comrnenter stated that EPA's conclusion that the landfilled
materials at the site are potentially leachable is not substantial
and therefore led EPA to develop highly theoretical risk-based
cleanup criteria.
EPA Response: EPA's conclusion that the landfilled materials are
potentially leachable is substantiated. The inorganic constituents
identified in the Remedial Investigation (RI) are compounds which
have the tendency to leach; therefore EPA does not agree that the
risk-based cleanup criteria developed for this site is highly
theoretical. When developing risk-based cleanup criteria, as
standard practice EPA uses "worst-case" scenarios. In the case of
the 62nd Street site, EPA developed cleanup criteria for the
constituents detected in the RI using the assumption that these
constituents have the potential to leach and are hazardous to human
health and the environment.
22.) The comrnenter contended that EPA failed to select a cost
effective remedy for the site in addition to finding little advantage
in the preferred remedy.
EPA Response: Sections 8 and 9 of the ROD clearly evaluate all
remedial alternatives, especially their overall protection of human
health and the environment and compliance with applicable or relevant
and appropriate requirements (ARARs) and standards, as well as cost.
EPA believes the selected remedy is the one which overall best meets
the nine evaluation criteria.
23.) The comrnenter noted that EPA's map showing the extent of the
lead contaminated groundwater plume is incorrectly drawn based on the
data presented on the map.
EPA Response: EPA has reviewed the reference figure and believes
that the plumes (both chromium and lead) are drawn correctly based on
the data presented in the map.
24.) The comrnenter stated that the groundwater data suggest a
pattern of contamination that is not consistent with the
characteristics of the materials identified at the site. The
chromium, nickel and lead seem more representative of electroplating
waste than the automobile waste.
EPA Response: The RI stated that chromium was also detected in
levels exceeding the Maximum Contaminant Level (MCL) in the
upgradient well, indicating a second source of contamination in the
area. In addition, the ROD states that "Wastes buried at the site
fall into two categories: auto part/battery wastes and cement
wastes. The auto part/battery wastes are highly contaminated, with
lead being the most prominent contaminant. The cement wastes contain
low levels of contaminants." So EPA believes the RI properly
identified the sources of the materials at the site and does not see
the inconsistency noted by the comrnenter.
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25.) The commenter stated that there appears to be no technical
justification for pretreating the contaminated groundwater onsite
because Publicly Owned Treatment Works (POTW) pretreatment standards
would not require pretreatment for contaminated water as
characterized in the RI.
EPA Response: EPA does not permit any groundwater exceeding Maximum
Contaminant Levels (MCLs) from Superfund sites to be discharged prior
to pretreatment. . Pretreatment of contaminated groundwater will be
conducted onsite and then discharged to either a local storm sewer, a
nearby creek or river, or aerated onsite in accordance with City of
Tampa and Hillsborough County Regulations, not sent to the POTW.
26.) The commenter recommended that a lower-cost alternative for
groundwater interception around the site using pumping wells rather
than an interceptor drain system be considered to collect
contaminated groundwater. The commenter's justification was that the
two systems functionally accomplish similar objectives and the onsite
interceptor drain system accounted for 37% of total project costs
while the extraction well system for the area south of the site
represented on 5%.
EPA Response: Section 4.2.2.1 of the Feasibility Study (FS) explains
extraction technologies, including both extraction wells and
subsurface drains. The main advantage of subsurface drains over
extraction wells is in contamination source control requirements at
the site. The contaminated plume will be contained onsite using the
subsurface drains. Offsite contaminated groundwater will be
collected using extraction wells. In choosing remedial alternatives,
EPA evaluates treatment technologies for overall long-term source
control and protection of human health and the environment. These
extraction technologies, along with stabilization/solidification
(S/S) of onsite material is the most effective remedial alternative
for the 62nd Street site.
27.) Th~'commenter expressed concern that RI/FS and proposed plan
documents'poTtray site problems in the context of contaminated soil
rather than' clearly stating that the site was actually "a landfill
operating under the tacit approval of local authorities." The
commenter, therefore, contended that the site should be managed in
the same way as all other landfills and not require "wholesale
cnemical treatment", which is unnecessary and unprecedented.
"
EPA Responsel This site primarily operated as an "unauthorized"
landfill for use by companies in the Tampa area. At the time of
investigations by the Florida Department of Environmental Regulation
(FDER), no closure plan was developed for the site. The data in the
RI and FS indicate that groundwater contamination is linked to
activities conducted on the site and materials currently remaining on
the site. One of the criteria EPA employs for evaluating treatment
technologies is the reduction of volume, mobility, and toxicity of
contaminants. In addition, the amendments to the Superfund law
require a "preference for permanent treatment". With'S/S, volume is
slightly increased but the mobility and toxicity of contaminants are
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greatly reduced. This remedy provides a permanent method of onsite
source control to prevent further leaching of contaminants to
groundwater. Direct contact risk is also significantly reduced. The
groundwater treatment systems will provide remediation of the
contaminated aquifer. The construction of a surface cap reduces
contaminant mobility of unsolidified wastes by preventing rainfall
infiltration and runoff of contaminated surface soils. Direct
contact risks fr~m the site are again reduced by construction of the
surficial cap.
28.) The commenter recommended that a closure and post closure plan
be developed for the landfill conforming to current state standards.
EPA Response: As stated in the preceding response, this site did not
operate under authority or oversight of local or state officials and
did not meet requirements for landfill facilities. Since it was
never an authorized municipal or industrial facility, it does not
have to be closed under current state standards. In addition, EPA
has determined that groundwater contamination has occurred from
materials at the site. Therefore, EPA has developed the most
appropriate remedy for the particular materials and contamination at
the 62nd Street Dump site.
29.) The commenter recommended that remediation of the contaminated
groundwater plume should be implemented without delay prior to soil
r.emediation to minimize further spread of contamination in a more
timely and cost effective manner.
EPA Response: With the information gathered during the RI and FS,
EPA believes that one ROD encompassing both source control and onsite
and offsite groundwater contamination will be the most efficient way
of addressing contamination at the site. The source and groundwater
remediation will be implemented simultaneously so that groundwater
concerns are addressed as quickly as possible.
IV.
Remainina Concerns
The community's concerns surrounding the 62nd Street Dump site will
be addressed in the following areas: community relations support
throughout Remedial Design/Remedial Action and incorporation of
comments/suggestions from the community into the Remedial Design.
Community relations will consist of making available final documents
(i.e., Remedial Design Work Plan, Remedial Design Reports, etc.) in a
timely manner to the local information repository for the site. EPA
will also issue fact sheets to those on the mailing list to provide
further information on progress of the project and schedules for
future activities at the site. EPA will inform the community of any
principal design changes made during the project design. If, at any
time during the Remedial Design or Remedial Action, new information
is revealed that could affect the implementation of the remedy or if
the remedy fails to achieve the necessary design criteria, the Record
of Decision may be revised with an opportunity for public comment to
incorporate new technology that will attain the necessary cleanup
objectives and goals.
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APPENDIX B
State's Concurrence Memorandum
62nd Street Site
Tampa, Hillsborough County, Florida
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APPENDIX C
Lead Memorandum
62nd Street Site
Tampa, Hillsborough County, Florida
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
O~~lce c~
SOLIO WA~"e ANO eMeRCE~CV ~E~p~'lsa
ME:MORANDUM
SUBJECT:
wt~ 2 I 1990
FROM:
Cleanup Level for Lead in Grou d
Henry L. Longest, Director
Office of Emergency and Reme
'1'0:
Bruce M., Diamond, Director
Office of Waste proqrams En
Patrick M. Tobin, Director
Waste Manaqement Division, Reqion IV
PURPOSE
, This memorandum addresses the issue of a protective cleanup
level for lead in ground water usable for drinkinq water, which
1s a major concern for several Superfund sites in Region IV.
i'
OBJECTIVE
The objective of this memorandum is to recommend a final
cleanup level tor lead in qround water usable tor drinkinq water
wh!ch will meet the CERCLA requirement that all Supertund
remedies be protective of human health and the environment.
BA.CKGROUN.Q
, '
", .
The 'current Maximum Contaminant Level (MCt) for lead is 50
ppb and was promulgated in 1975 as an interim national primary
drinking water regulation (NPDWR) under the Safe Drinking Water
Act (SDWA). On November 13, 1985, the A98ncr beqan the process
of revising this standard by proposing a MaXlmum contaminant
Level Goal (MCLG) as required by the SDWA (50 Ii 46936).
OnAuqus~ 18, 1988 EPA proposed an MCLG tor lead at zero and
an MCt ot 5 ppb (53 LB 31516). Also, since the primary cause of
lead-contaminated drinking water is corrosion of lead-bear1nq
pipes in public water supply (PWS) distribution systems'and/or
household plumbinq, the proposed rule would direct PWSs to meet
treatment technique requirements and to deliver public education
to reduce and minimize exposures to lead in drinking water.
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These require~ents would be triggered ~hen an action level
is exceeded at consumers' taps throughout the water distribution
system. The Agency proposed an action level of 10 ppb, on
average, to trigger corrosion control and public education.
Another lead action level of 20 ppb, measured at the 95
percentile of samples, was proposed as a trigger for public
education.
The Agency is considering promulgation of treatment
technique requirements which may include additional source water
treatment, lead service connection replacement, and public
education if lead concentrations at the tap exceed an action
level. Any such technological treatment targets will provide
substantial health protection. A final rule is being worked on,
and is scheduled for promulgation in December 1990.
DISCtJSSION
NO cancer potency factor or reference dose has been
promulgated for lead; therefore, an assessment of protective
levels of lead in ground water that may be used for drinking
water purposes will be based on current data. The Agency has
identified 10 micrograms per deciliter (ug/dl) as a blood lead
level of concern in young children. Blood lead levels above 10
ug/dl are associated with increased risks of potentially adverse
effects on neurological development and diverse physiological
functions.
Attached is available data that support the recommended
final cleanup level for lead in drinking water at Superfund
sites. This information includes the June 15, 1990, EPA draft
final report entitled, "Contributions To a Risk Assessment For
Lead in Drinking Water" and the June 1986, EPA draft final report
entitled, "Air Quality criteria for Lead" (Volume III of IV, p.
11-129). Based on these data, lead levels in drinking water of
15 ppb and lower should correlate to blood lead levels below the
.concern level of 10 ug/dl. The Agency estimates that steady
exposure to a water lead concentration of 15 ppb would
contribute, at most, 2-3 ug/dl to a child's blood lead. Sources
of lead other than drinking water (e.g. food, air, soil, dusts)
typically contribute approximately 4-5 ug/dl to children's blood
lead. Accounting for the variability inherent
in childhood behavior, nutrition, and physiology, it is
estimated that total lead exposure, given 15 ppb in drinking
water, would result 1n blood lead levels below 10 ug/dl in
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roughly ~9 percent of young children who are not exposed to
excessive lead paint hazards or heavily contaminated soils.
Therefore, a 15 ppb cleanup level would provide substantial
health protec~ion for the majority of young children. Most of
the remaininq lead problem will continue to be contaminated
soils and old. lead-painted housinq.
In an April 10, 1989, Federal Register notice (54. lB
14316), EPA announced the availability of a guidance document and
testing protocol entitled, "Lead in School's Drinking Water" to
assist schools in determininq the source and degree of lead'
contamination in school drinking water supplies and how to remedy
such contamination. That document, which 1s also attached,
recommends that schools take remedial steps whenever the lead
level at any drinking water outlet exceeds 20 ppb.
RECOMMENDATION
Based on a review of these and other studies, it is
recommended that a final cleanup level of 15 ppb for lead in
ground water usable for drinking water is protective. If water
used for drinking purposes subsequent to achieving'the cleanup
goal in the aquifer may need further treatment to account for
lead contributions related to the distribution of water through
pipes, the responsibility for this additional treatment or the
replacement of lead-bearing water pipes lies with the persons who
are using or distributing the water. A concentration of lead of
15 ppb in drinkin; water should generally correlate with a blood
lead level below the concern leval of 10 uq/dl. In some
situations, lower cleanup levels may be appropriate based on
site-specific factors, such as multiple pathways ot exposure
caused by lead from the site.
If.,the remedial action will include treatment. and supplyinq
water directly to the public: for drinking water consumption,
compliance with a 15 ppb action level should be met at 90 percent
of the taps to ensure that t.he remedy is protective. When the
lead NPDWR is promul~ated, applicable or relevant and appropriate
requirement.s of that rule should be met.
FUTURE C;Y~DANCE
After promulgation of the lead NPCWR, quidance will be
issued discussing those provisions of the rule that may be
applicable or relevant and appropriate for Superfund actions.
For further information, please contact T1sh Zimmerman at
FTS 382-2461 or Neilima Senjalia at FTS 475.7027.
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DISCLAIMER
The reco~~endations in thi~ docu~ent are intended solely as
guidance. They are not inte~ded and cannot be relied upon to
create any rights, substantive or procedural, enforceable by any
party in liti~ation with the United States. EPA reserves the
right to act at variance with these reco~~endations and t~
change the~ at any ti~e without public notice.
Attach~ents
cc: Directors,
Directors,
II
Directcrs,
VI, IX
Directors,
Waste Ma~age~e~t Division, Regions I, V, VII, VIrr
E~crgency and Re~e1ial Response Division, Regio~
Hazardous Waste Manage~ent Division, Regions I:I,
Hazardous Waste Divisio~, Region X
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