United States Office of
Environmental Protection Emergency and
Agency Remedial Response
Superfund
Record of Decision
EPA/ROD/R06-92/073
September 1992
PB93-964210
I
Double Eagle Refinery, OK
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1
NOTICE
The appendices Hsted in the index that are not found in this document have been removed at the request of
the issuing agency. They contain material which supplement but adds no further applicable information to
the content of the document All supplemental material is, however, contained In the adminisliaUve record
for this site.
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DECLARATION
DOUBLE EAGLE REFINERY SITE
Statutory Preference for Treatment
as a Principal Element
is Met and Five-Year Review not Required
SITE NAME AND LOCATION
Double Eagle Refinery Site
Oklahoma City, Oklahoma
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Double Eagle Refinery Site (DER site), in Oklahoma City,
Oklahoma, which was chosen in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980
(CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and, to the extent practicable,
the National Contingency Plan (NCP). This decision is based on the
Administrative Record for this site.
The State of Oklahoma agrees 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, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
This Record of Decision (ROD) addresses the source of contamination
both on and off the site, which includes surface sludges,
contaminated water and sediment, and contaminated soil and debris.
This action is the first operable unit for the DER site. The first
operable unit will also be referred to as the "Source Control
Operable Unit". A second operable unit for the DER site will
address ground waters beneath the site in a subsequent ROD. The
second operable unit will be referred to as the "Groundwater
Operable Unit".
This Source Control Operable Unit addresses the principal threat at
the site by neutralizing the acidic sludges thereby reducing the
potential for contaminant migration to surface waters and ground
waters. The principal threat at the DER site is posed by direct
contact and inhalation, and potential for migration of contaminants
to the ground water. The remedial objectives are to minimize
potential exposure by direct contact or inhalation, and to reduce
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the potential for migration of contaminants into the surface waters
and ground waters. This action also addresses the low level threat
at the site by chemically binding the hazardous constituents
together in a matrix which eliminates potential exposure via the
following pathways: inhalation, incidental ingestion, and dermal
contact.
The major components of the selected remedy include:
Cleaning, consolidation, demolition as necessary, and salvage or
removal of contaminated equipment and structures on-site, in order
to implement the remedial components specified below;
Consolidation of off-site and on-site wastes (42,000 cubic yards
of contaminated material estimated) on site;
On-site neutralization of the consolidated acidic wastes;
On-site stabilization and solidification of wastes containing
lead;
Off-site disposal of the treated waste in a landfill permitted to
accept the waste.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment technologies to the maximum
extent practicable and satisfies the statutory preference for
remedies that employ treatment that reduces toxicity, mobility, or
volume as a principal element.
Because this remedy will not result in hazardous substances
remaining on site above health-based levels, a review will not be
conducted within five years after commencement: of remedial action
to ensure that the remedy continues to provide adequate protection
of public, health, welfare, and the environment.
B.J. Wynne Date
Regional Administrator
Region 6
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DOUBLE EAGLE REFINERY
RECORD OF DECISION
TABLE OF CONTENTS
I. Site Name, Location, and Description 1
II. Site History and Enforcement Activities 7
A. Site History. 7
B. EPA Enforcement Activities 8
C. State Enforcement Activities 8
III. Highlights of Community Participation 9
IV. Scope and Role of Operable Unit 1 10
V. Summary of Site Characteristics 10
A. General Overview 10
B. General Geology and Hydrogeology Characterization... 11
C. Site Hydrogeologic Conditions 13
D. Nature and Extent of Contamination 13
E. Discrete Areas of Contamination 14
1. Sludge Lagoon 14
2. Surface Impoundments 17
3. Spill Areas 17
4. Radio Tower and Parcel H 18
VI. summary of Site Risks 18
A. Human Health Risks 18
B. Land Use 19
1. Current Land Use 19
2. Future Land Use 20
C. Identification of Chemicals of Concern 21
D. Exposure Assessment 21
1. Current Exposure Pathways 21
2. Future Exposure Pathways 23
3. Exposure Scenarios 26
E. Toxicity Assessment 28
F. Human Health Risk Characterization 31
1. Current Risk Characterization 31
2. Future Risk Characterization 33
G. Central Tendencies 35
H. Uncertainties with the Human Health Risk
Calculations 35
I. Ecological Risks 43
1. Receptor Characterization and Endpoints 43
2. Toxicological Response Assessment 44
3. Exposure Assessment 45
4. Risk Characterization 45
VII. Remedial Action Goals 45
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VIII. Description of Alternatives 47
A. Remedial Action Alternatives 48
1. Common Elements 48
2. No Action 49
3. Limited Action 49
4. Onsite Stabilization and Capping 50
5. Onsite Stabilization/Onsite Landfill Disposal... 54
6. Onsite Stabilization/Offsite Landfill Disposal.. 55
7. Onsite Incineration/Onsite Ash Disposal 57
8. Offsite Incineration/Offsite Ash Disposal 58
IX. Summary of Comparative Analysis of Alternatives 60
A. Nine Criteria 60
1. Threshold Criteria 60
2. Balancing Criteria 61
3. Modifying Criteria 61
4. Comparative Analysis 61
X. The Selected Remedy 65
XI. Statutory Determinations 67
A. Protection of Human Health and Environment 67
B. Compliance with ARARs 67
C. Chenical-Specific ARARs 68
D. Action-Specific ARARs 68
E. Cost Effectivenss 68
C. Utilization of Permanent Solutions and Treatment.... 69
D. Preference for Treatment as a Principal Element 69
XII. Documentation of Significant Changes 69
Administrative Record Index Attachment A
Responsiveness Summary Attachment B
Letter of State of Oklahoma Preference Attachment C
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50272-101
REPORT DOCUMENTATION 1. REPORT NO. 2.
PAGE EPA/ROD/R06-92/073
4. TMeendSubMe
SUPERFUND RECORD OF DECISION
Double Eagle Refinery, OK
First Remedial Action - Subsequent to follow
7. Authof(«)
9. Pertaining OrgeinlalionNeine end Addreee
12. Sponsoring Organization Name and Addnwe
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
3. Recipient1* Acceaeion No.
5. Report Dele
09/28/92
6.
8. Performing Organization Rept No.
10. ProJect/Tiek/Work UnH No.
11. Contnct(C) or Gr*nt(G) No.
(C)
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EPA/ROD/R06-92/073
Double Eagle Refinery, OK
First Remedial Action - Subsequent to follow
Abstract (Continued)
and onto Radio Tower, which contains a surficial tar matrix. EPA investigations revealed
42,000 cubic yards of contaminated soil, sediment, surface water, and air. Contaminated
areas included a sludge lagoon, surface spill area, surface impoundments, and process
equipment. This ROD addresses a final remedy for OU1, Source Control Operable Unit. A
subsequent ROD will address ground water contamination. The primary contaminants of
concern affecting the soil, sediment, sludge, debris, and surface water are VOCs,
including benzene and PCE; other organics, including PAHs and PCBs; metals, including
arsenic and lead; and acids.
The selected remedial action for this site includes excavating approximately 2,700 cubic
yards of contaminated materials from the two offsite areas, Radio Tower and Parcel H, and
consolidating these onsite within the East/West lagoon along with contaminated materials
from the DER impoundment and open areas; treating the 42,000 cubic yards of consolidated
materials onsite using neutralizing agents for the acidic wastes and
solidification/stabilization to remove inorganics; using surface water from the
impoundments in the stabilization processes; excavating the solidified material and
transporting this offsite for disposal in a RCRA landfill; demolishing contaminated
onsite equipment or structures, including above-ground storage tanks, with salvage and/or
removal; disposing of any asbestos-containing material, as needed; and monitoring ground
water. The estimated present worth cost for this remedial action is $6,400,000. There
are no O&M costs associated with this remedial action.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific goals for soil, sediment, and sludge are based on meeting a risk of 10~4
to 10~6and an HI=10, including lead 500 mg/kg; PAHs; and PCBs 25 mg/kg. All other
residual materials will meet RCRA TCLP regulatory limits prior to offsite disposal.
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RECORD OF DECISION
DOUBLE EAGLE REFINERY SITE
OKLAHOMA CITY, OKLAHOMA
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
SEPTEMBER 1992
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CONCURRENCE DOCUMENTATION
FOR THE
DOUBLE EAGLE REFINERY
f s // ^^^it/^
Sre Remedial Project Manager
Office ^f Regional Counsel
Site Attorney
Edlund, Chief
rfund Programs Branch 6H-S
/>tieorge Alexander,
^ Regional Counsel 6C
JQlyn M. Davis/ Director
Hazardous Waste Management
Division 6H
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DECISION SUMMARY
FOR THE
DOUBLE EAGLE REFINERY SITE
OKLAHOMA CITY, OKLAHOMA
I. SITE NAME. LOCATION. AND DESCRIPTION
The Double Eagle Refinery Site ("DER site", or "the site") occupies
the Southeast Quarter (SE 1/4) of Section 35, Township 12 North,
Range 3 West, Indian Meridian, Oklahoma County, Oklahoma City,
Oklahoma. Located at 1900 NE First Street, the site is bounded to
the north by the Union Pacific Railroad tracks and to the east,
west, and south by vacant lots zoned for industrial land use.
Martin Luther King Boulevard lies on the east side of the site as
an overpass to the railroad tracks.
The Fourth Street Refinery Superfund Site ("FSR site") lies about
500 feet northeast of the DER site, just north of the railroad
tracks and just east of Martin Luther King Boulevard. The DER and
FSR sites are essentially adjacent to each other, and contain very
similar waste material since both sites recycled used oils. Due to
the fact that these sites are in such close proximity, and
migration of contaminants in certain cases overlap, this Record of
Decision (ROD) will make reference to the FSR site as necessary.
The FSR site will be addressed in a separate ROD. Figure l
provides a general location map, and shows the location of each
site in relation to the other. Figure 2 provides a schematic of
both the DER and FSR Superfund sites.
The DER site is fenced and extends over approximately 12 acres in
which there are discrete areas of concern: a sludge lagoon, six
smaller earthen impoundments, and numerous structures and pieces of
abandoned refinery equipment. An inventory done in 1990 by the
site owner is as follows: 13 steel buildings, one fire tube
boiler, two pipe heat exchangers, five vacuum precoat/scrapper
filters, two concrete settling cells, and an undetermined number of
steel tanks (approximately 100) of varying dimensions. All tanks
are empty, although most equipment may be contaminated to various
degrees. One of the concrete cells contains residual waste
material mixed with rainwater. Since this inventory, the site
owner has salvaged some equipment from the site. Figure 3 is a
layout of the DER site surface features.
Although industrial areas surround the site, the land use within a
1 mile radius of the DER site is mixed industrial and residential.
One residence is located to the north of the railroad tracks and to
the east of Martin Luther King Boulevard, adjacent to the FSR site.
A small neighborhood is located about 1/4 mile to the north, on the
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OKLAHOMA
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FIGURE 1
Double Eagle and Fourth Street
Super?und Sites.
Oklahoma City, Qklahaona
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other side of the industrial complex adjacent to the railroad
tracks which border the site. Four schools (Douglas High School,
Dunbar School, Bath School, and Edwards School) are located within
a 1 mile radius of the site. Recreational areas close to the site
include the Douglas Community Center, Douglas Community Park, and
Washington Park. Drug Recovery, Inc. is the only medical facility
located within a 1 mile radius of the site.
The DER site has contributed to off-site contamination in areas
just south and just east of the site, which are the "Radio Tower
Area" and the "Parcel H Area", respectively. Both off-site areas
are unfenced. The contamination at the Radio Tower Area consists
of a surficial tar matrix which covers approximately 0.25 acre.
The contamination at the Parcel H Area which is attributable to
past site operations includes two surficial ponds, approximately
0.5 acre. Since the FSR site has also contributed to the
contamination in these ponds, the Parcel H discussions in this ROD
will be repeated in the FSR ROD.
Both off-site areas are shown in Figure 3, which is a schematic of
the DER site. However, a more detailed view of the Parcel H Area is
shown in Figure 4, which is a schematic of the FSR site. The
"Landfill Area", located just west of the ponds 1 and 2 on Parcel
H in Figure 4, is not attributable to either the DER or FSR site
past operations. (It should be noted that the Parcel "H" area in
Figure 3 is not to scale).
Both the DER site and portions of the Radio Tower and Parcel H
areas have been identified as wetlands. The North Canadian River
is located just south of Interstate 35, approximately one half mile
south of the site. Although no endangered species have been
identified for these areas, wildlife in the area includes migratory
fowl and small mammals.
No drinking water wells are located within a 1 mile radius of the
site. The oil well drilling operations in the early 1920's may
have impacted the alluvial aquifer. This zone could be considered
a Class III aquifer due to salinity. The shallow ground water
beneath both the DER and FSR sites has levels of Total Dissolved
Solids as high as 13,100 ppm.
The interconnection between the alluvium and the deeper drinking
water aquifer (Garber-Wellington) is currently undergoing further
study for both the DER and FSR sites. In addition, the alluvial
connection and potential impact of site contaminants migrating to
the North Canadian River will need further evaluation. A separate
ROD will address the potential migration of site contaminants via
the ground water pathway for the DER site as the Groundwater
Operable Unit (GOU), or Operable Unit 2.
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H. SITE HISTORY AND ENFORCEMENT ACTIVITIES
Site History
The DER collected, stored, and re-refined used oils and distributed
the recycled product. The refinery was active as early as 1929
with historical aerial photographs available as early as 1941.
Generally, early refining was conducted on the western portion of
the site and expanded toward the eastern portion as the operations
increased.
The DER recycled approximately 500,000 to 600,000 gallons of used
motor oil per month, into finished lubricating oil. The recycling
process consisted of the addition of sulfuric acid, settling, and
filtration with bleaching clays via a filter press. This process
generated approximately 80,000 gallons of oily sludge per month.
Sludges were initially sent to an off-site disposal facility, now
the Hardage Criner Superfund Site located in Criner, Oklahoma.
Later, sludges were disposed of in on site impoundments and a
sludge lagoon until the late 1960's to early 1970's. Double Eagle
continued to accept waste oil for storage until 1980.
On-site and off-site visual inspections, by the Environmental
Protection Agency (EPA) Field Investigations Team in May of 1985,
indicated that a preliminary sampling inspection should be
conducted. An aerial photograph dated 1979 showed vehicle tracks
from the site leading to the Radio Tower area where contamination
similar to that found onsite was observed. Off-site sampling in
the southwestern drainage area and at the Radio Tower area during
January of 1986 revealed elevated levels of target compounds that
were also found in the waste impoundments on site.
An Expanded Site Inspection was conducted by EPA in 1987-88 which
confirmed that the site should be ranked for inclusion on the
National Priorities List (NPL). In March 1989, the DER site was
added to the NPL, pursuant to Section 105 of the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA),
42 U.S.C. Section 9605, as amended.
Prior to initiation of a Remedial Investigation and Feasibility
Study (RI/FS) for the site, a review of the historical topography
of the site and surrounding area revealed that drainage from the
DER site onto Parcel H had occurred at one time. A site scoping
visit was conducted to follow up on possible Parcel H
contamination.
Physical dumping at the edge of the eastern-most pond on Parcel H
appeared likely. Although drainage from the FSR site to Parcel H
did not appear likely due to the diking on each side of the
railroad tracks, historical aerials were the only source of
information for the FSR site operations. During periods of very
heavy rainfall drainage from the DER site has occurred. Further
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sampling conducted on Parcel H in April of 1990 revealed elevated
levels of lead in the sediments of ponds on Parcel H. Due to the
similar waste characteristics of both sites, one objective of the
RI/FS was to sample the waste on Parcel H for determining the
contribution of contamination in relation to either, or both, the
DER and FSR sites.
The RI/FS project was initiated in May 1990 for the DER site; and
the Rl and FS were completed in May and June of 1992, respectively.
Due to the close proximity of the DER and FSR sites, and due to the
similar types of wastes present at both sites and at both off site
areas, EPA assigned one contractor to conduct the RI/FS projects
concurrently. Therefore, distinguishable characteristics of each
site could be easily identified and efforts would not be duplicated
for the overall study area. The specialized "fingerprinting
effort" for the off-site areas was performed by EPA's Environmental
Monitoring Systems Laboratory in Las Vegas, Nevada, in coordination
with the Alternative Remedial Contractor (ARCS) given the RI/FS
project. This will be discussed further in Section V - Summary of
Site Characteristics; Discrete Areas of Concern.
EPA Enforcement Activities
In December 1988 EPA issued an Administrative Order (AO) to the
site owner, requesting that the north side of the site be fenced to
prevent people and animals from coming into direct contact with the
hazardous substances. The owner complied with the AO and completed
the fencing in February 1989, which mitigated the immediate risk to
public health.
Prior to initiating the RI/FS, EPA conducted a search for
Potentially Responsible Parties (PRP's). EPA sent Special Notice
letters to 17 PRP's identified in the search. The letters included
a notification of potential liability under Section 107 of CERCLA.
The letters also included a demand for reimbursement of EPA's past
costs as well as an offer affording the PRP's to perform the RI/FS.
None of the parties receiving the Special Notice made a good faith
offer to conduct the RI/FS; nor did any parties offer to reimburse
the EPA for the past costs incurred.
EPA conducted the RI/FS as a Fund lead project. Simultaneously
with the performance of the RI/FS, EPA proceeded to pursue leads
regarding other unidentified PRP's. Consequently, information
request letters were sent to numerous parties other than the 17
previously identified PRP's. The PRP search is continuing at the
present time.
State Enforcement Activities
During 1977 and 1978 numerous inspections conducted by the Oklahoma
Water Resources Board (OWRB) indicated that un-permitted releases
of hazardous waste occurred both on and off-site. Subsequent
inspections conducted by OWRB revealed that the Double Eagle
8
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facility continued to discharge hazardous substances in violation
of the facility permit. As a result of the un-pennitted releases of
hazardous waste, OWRB referred this case to their General Counsel
seeking a Cease and Desist Order on September 14, 1985.
m. HIGHLIGHTS OF COMMUNITY PARTICIPATION
This decision document presents the selected remedial action for
the DER Superfund site, in Oklahoma City, Oklahoma, chosen in
accordance with CERCLA, as amended by the Superfund Amendments and
Reauthorization Act (SARA) and, to the extent practicable, the
National Contingency Plan (NCP). The decision for this site is
based on the administrative record. An index for the adminstrative
record is included as Attachment A to this document.
The public participation requirements of CERCLA, sections
113(k)(2)(B)(i-v) and 117, were met during the remedy selection
process. The Remedial Investigation report, released in May 1992,
the Feasibility Study report, released in June 1992, and the
Proposed Plan, released in July 1992, were all made available to
the public in both the administrative record and information
repositories; maintained at the Ralph Ellison Branch Library, the
Oklahoma State Department of Health (OSDH) Central Office in
Oklahoma City, Oklahoma, and the EPA Region 6 Office in Dallas,
Texas. The notice of availability for these documents was
published in The Daily Oklahomian and The Black Chronicle, on July
17, 1992.
The OSDH and EPA held an Open House in Oklahoma City on August 4,
1990, to explain the Superfund process and to notify the public
that RI activities were going to begin. The RI fieldwork was
discussed and information about the site was provided to the public
by the EPA.
A Work Shop was held in the Spring of 1991, to discuss initial
field results and futher work planned. On June 25, 1992, the OSDH
and EPA held an Open House in Oklahoma City, to inform the public
of the findings of the RI Report which included the results of the
Baseline Risk Assessment. EPA and OSDH also discussed the various
alternatives of remediation considered in the RI/FS.
A 30-day public comment period was held from July 17, 1992 to
August 15, 1992. No requests were received to extend the comment
period. One written comment was received during the public comment
period.
A public meeting was held in Oklahoma City on July 23, 1992. At
this meeting, representatives from the OSDH and EPA presented
information on the RI, Risk Assessment (RA) and FS. EPA and OSDH
answered questions about the site, the remedial alternatives under
consideration, and the Proposed Plan of Action. A response to the
comments received at this meeting and during the 30-day comment
period is included in the Responsiveness Summary, which is included
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in this ROD as Attachment B.
IV. SCOPE AND ROLE OF OPERABLE UNIT 1 WITHIN THE SITE STRATEGY
Principal threat wastes are those source materials considered to be
highly toxic or highly mobile that generally cannot be reliably
controlled and that present a significant risk to human health or
the environment should exposure occur. The principal threats at
the DER site are the acidic sludges and contaminated ponds. These
discrete waste areas present the most significant risk at the site,
due to the potential for exposure through direct contact and
inhalation. The risk is also increased due to the concentrated
nature of the waste which presents a high potential for migration
of contaminants to surrounding areas and the underlying ground
water.
Low level threats are those source materials that generally can be
reliably managed with little likelihood of migration and that
present a low risk in the event of exposure. The low level threats
at the site are the contaminated soils and tar matrices, both on
and off-site. These areas are not as highly mobile as the acidic
sludges and the material in the ponds on-site and the concentration
of contaminants is more dilute which decreases the risk from
potential exposure.
The principal threat at the DER site is posed by direct contact and
inhalation, and potential for migration of contaminants to the
ground water. The remedial objectives are to minimize potential
exposure by direct contact or inhalation, and to reduce the
potential for migration of contaminants into the surface waters and
ground waters.
During the RI/FS project for the DER site, the issues related to
the ground waters beneath the site were acknowledged as complex in
comparison to those issues apparent for the source contamination.
Although shallow and deep wells were installed around the perimeter
of both the DER and FSR sites, the determination of vertical and
lateral migration of contaminants will require further study. The
impact of the migration of contaminants in ground water and surface
water will be addressed in a future Record of Decision, Operable
Unit 2 (Groundwater Operable Unit - GOU). This ROD will address
the source of contamination at the DER site, Operable Unit 1
(Source Control Operable Unit - SCOU).
V. SUMMARY OF SITE CHARACTERISTICS
General Overview
The DER site and off-site areas are not located in the 100 year
floodplain. Generally, the local surface drainage flows to the
south and east of the DER site. Prior to construction of
Interstate 35, the North Canadian River meandered through the
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adjacent FSR site. During construction of the highway, the river
was diverted to the south side of 1-35; and is now located
approximately one half mile to the south of the DER site.
Ponds on the DER site and portions of the off-site areas appear on
the National Wetlands Inventory Maps (NWI) (U.S. Dept. of Interior,
Fish and Wildlife Service, 1989). These maps are based on
interpretation of aerial photographs and not on actual site
surveys. Vegetation around open water areas on Parcel H appears to
consist of grasses, likely to be prairie grass species rather than
wetlands species. Wetlands classification of the DER site and off
site areas will be discussed in detail under Section VI (Summary of
Site Risks - Ecological Risks).
General Geology and Hydrogeology Characterization
The DER site is situated on Quaternary alluvial deposits which
represent recent deposition by the nearby North Canadian River.
The floodplain deposits typically consist of unconsolidated and
interfingering lenses of sand, silt, clay, and gravel. These
alluvial sediments are predicted to have relatively high
permeabilities and porosities. The alluvium in Oklahoma County
ranges in thickness from several inches to 90 feet below ground
suface along the river basin.
The predominant outcropping geologic formation beneath the DER site
includes the Garber and Wellington Formations. These bedrock
formations (i.e., lithified strata below the alluvial channel fill)
have a gentle westward homoclinal regional dip of 30 to 40 feet per
mile and are located approximately 50 feet below the surface at the
DER site. Collectively, the Garber-Wellington consists of massive,
cross-bedded sandstones irregularly interbedded with siltstones and
shales. The "red bed" sandstones and shales of the Garber and
Wellington Formations are similar in lithology and conform
gradationally. Therefore, these formations are commonly mapped as
a single lithologic unit and classified as a single aquifer (the
Garber-Wellington aquifer). See Figure 5 for a cross-section of
the subsurface.
The Garber-Wellington aquifer constitutes the most important source
of ground water in Oklahoma County. Wells drilled into the water
bearing zone may penetrate as much as 200 to 300 feet of water
bearing sandstone. Artesian conditions exist below 200 feet in
areas in which the aquifer is overlain by the Hennessey Group. The
depths of municipal, institutional, and industrial wells screened
in the Garber-Wellington range from 100 to approximately 1,000 feet
in Oklahoma County. Yields of wells less than 250 feet deep range
from 5 to 115 gallons per minute (gpm) and average 35 gpm.
Reported yields of wells more than 250 feet deep range from 70 to
475 gpm and average 240 gpm. The principal hydrologic factor
controlling the development of the aquifer for fresh water supply
is the presence of a deeper saline water wedge.
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No private wells currently exist within a 1 mile radius of the
site. Residents and industries in the area utilize city water,
which is obtained from reservoirs surrounding the city. Results
from sampling the shallow ground water beneath both the DER and FSR
sites indicate Total Dissolved Solids (TDS) from 310 ppm to 13,100
ppm. High conductivities were also documented, with several
readings greater than 20,000 milli-moles. These conditions confirm
the presence of saline water beneath the site which would prohibit
use of the shallow ground waters for domestic use.
The Hennessey Group formation, predominantly reddish-brown shale
containing some layers of siltstone and fine-grained sandstone,
overlays the Garber-Wellington Formation in the vicinity of the
site. However, this shale layer was not encountered above the
Garber-Wellington aquifer (as originally anticipated) in the deeper
borings drilled at both the DER and FSR sites in March of 1992.
Due to the absence of the Hennessey Shale beneath the site, a
separate study is plannned to assess the vertical migration and
potential impact of site contaminants on the deeper Garber-
Wellington aquifer. In addition, the lateral migration and
potential impact of site contaminants on the nearby Canadian River
will be investigated. The results of this study will be utilized
to complete the ROD for the GOU.
Site Hydrogeologic Conditions
At the Double Eagle site and Parcel H area, the upper one to five
feet of surface material encountered during well boring generally
contained a thin (two to six inches thick) layer of stained soil
and/or waste material within a variable sand and clay matrix.
Underlying this shallow zone of contamination, geologic
observations indicate a classic, fining-upwards alluvial sequence
consisting of lenticular beds of clay, silt, sand and gravel.
During drilling operations, groundwater was encountered at varying
depths that ranged from 7 to 20 feet below ground surface.
Groundwater elevations have been determined periodically at the DER
site and reveal that the level of groundwater exhibits moderate
seasonal fluctuation.
Nature and Extent of Contamination
The Source Control RI/FS was focused to provide information for
discrete areas of concern and subsequent migration pathways, given
the type of oily matrix encountered at the site. The discrete
areas of concern are well delineated waste areas at the DER site:
a sludge lagoon, six smaller earthen impoundments and two concrete
cells (one empty), and spill areas around numerous structures and
pieces of abandoned refinery equipment. In addition, the off-site
"Radio Tower" and "Parcel H" areas were included in the
investigation, as discussed under Section I.
13
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Figure 3 is a schematic of the DER site and also shows the off-site
areas (the Radio Tower area and Parcel "H") to be discussed.
Figure 4 is a schematic of the FSR site, which shows a more
accurate location of Parcel "H", located south of the FSR site and
railroad tracks, and east of the landfill area (just north of the
drainage pond). Figure 6 is a conceptual model of the site, used
for visualizing the potential exposure pathways of concern. As
discussed previously, the ground water pathway is currently
unknown. Therefore, this pathway is presented as incomplete in the
current conceptual model, but will be evaluated under the GOU ROD.
From all the chemicals detected in various media at the site,
certain chemicals were originally identified as potential
Contaminants of Concern (COC). This determination was based upon
concentrations detected, toxicity of the compound, and persistence
in the environment. COC's attributable to site activities include
Polycyclic Aromatic Hydrocarbons (PAHs), chlorinated hydrocarbons
(which include 1,2-Dichloroethane, Tetrachlorethene,
Trichloroethene) and polychlorinated biphenyls (PCBs), alkly
benzenes, ketones (particularly 2-butanone), lead, arsenic, and
antimony. Lead is the primary COC given the widespread occurance
in all media, and the extremely high concentrations (up to 20,000
ppm) in sludge and contaminated soils or sediments. Exposure could
potentially occur due to direct contact (incidental ingestion) as
well as inhalation. The COC's are discussed in detail in Section
VI - Summary of Site Risks.
Although the air pathway contributed the greatest risk and hazard
index for organics detected, a trend is not apparent to suggest
that the site contributes to the ambient air contaminant levels of
the surrounding area. This is due to high gasoline constituent
levels measured upwind of both the DER and FSR sites; probably due
to the areas surrounding both sites being highly industrialized.
Similarly, particulate air sampling results for lead were high
(17.9 ug/m3) onsite. However, upwind locations were higher (32
ug/m3).
Discrete Areas of Concern
a) Sludge Lagoon
Evaluation of the sludge lagoon was completed upon visual
inspection of borings over a 20 by 20 foot surveyed grid system
tied to the larger 100 by 100 foot surveyed grid system for the
entire site (see Figure 7). Samples were collected randomly from
the smaller grid, both laterally and vertically, for full scan
analysis (Target Compound List - TCL) under the Contract Laboratory
Program (CLP). In addition, samples were obtained for indicator
parameter analysis (Total Petroleum Hydrocarbons - TPH, pH, Lead,
and Chromium) to correlate with visual observations and full scan
analysis. Also, technology screening samples were collected
(physical parameters such as density, grain size distribution,
solubility, viscosity, heat content, etc.).
14
-------
\
-------
u
i
I
U.
LJ
U
S s
LJ
fe
j >- ^
r- M *<> o>
u, ^° fi
a
u
3 VJ
«3
13
ji
I
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g
I
{ >>
i!?;,.
IJJlfli
16
-------
Discrete depth samples were not planned since an initial inspection
of the lagoon prior to Work Plan approval did not reveal
distinguishable differences vertically within the lagoon. However,
the eastern and western portions of the lagoon were identified as
physically different based on apparent differences in the tar to
clay content. Therefore, the samples obtained for characterization
of the waste material were collected from two areas of the sludge
lagoon (East vs West in Figure 3) which appeared to be physically
different.
Results of this sampling effort show that the chemical composition
of the eastern and western portion of the sludge lagoon are not
significantly different. Vertical versus lateral composition did
not vary significantly, either. In general, the correlation
between visual observations and indicator parameters was only
loosely established. However, lead concentrations did increase
with higher TPH content in the sludge matrix and higher acid
content. The estimated volume of sludge material in the lagoon is
approximately 35,000 cubic yards.
b) Surface Impoundments
The impoundments onsite are not large and were assumed to be
homogeneous in nature and composition. All of the earthen
impoundments are unlined. The two concrete cells on the northwest
corner of the site (area #1 on Figure 3), were regularly drained
and cleaned for re-use of the bleaching clay material during active
operations at the site. Drainage was directed towards the earthen
impoundments to the south (area #2 on Figure 3).
Water and sediment samples were collected from all of the earthen
impoundments; only a water sample was collected from the concrete
cells since these areas were routinely cleaned and drained as
described above. All samples were analyzed for TCL compounds and
some samples were analyzed for technology screening parameters.
Results of this sampling indicated that sediments in all the ponds
were similar in chemical composition across the site and also in
comparison to that material in the main sludge lagoon. Water
samples were also fairly uniform across the site and the
contaminants detected were also detected in the main sludge lagoon,
although at reduced concentrations. This was anticipated since
these ponds now collect runoff from similar drainage areas.
Contaminated sediments in the earthen impoundments is estimated at
approximately 715 cubic yards. Contaminated material remaining in
the east concrete cell is estimated at 474 cubic yards.
c) Spill Areas Surrounding Process Equipment
Although the sludge lagoons and ponds on-site were of major
concern, spill areas surrounding the process equipment and drainage
pathways were also investigated. Contaminants found in the sludge
and pond sediments are also present in the stained spill areas.
17
-------
The volume of contaminated material for these areas is estimated as
2,204 cubic yards.
d) Radio Tower and Parcel H Areas
The contamination at the Radio Tower Area consists of a surficial
tar matrix which covers approximately 0.25 acre. The volume
estimate for this material is about 1,500 cubic yards.
The contamination at the Parcel H Area includes oily sediments in
two surface ponds, which contain high lead concentrations. The
concentrations of lead encountered in the sludge from the ponds at
Parcel H ranged from 199 to 8,780 mg/kg. The concentrations of
lead encountered in the sediments from the ponds ranged from 5,550
to 19,900 mg/kg. Each pond is approximately 0.25 acre in size.
The volume estimate for contaminated sediments in both ponds is
2,400 cubic yards, assuming a 3 foot depth for each pond.
The EPA Environmental Monitoring Systems Laboratory (EMSL) has
evaluated existing data and analyzed samples from both the DER and
FSR sites and the Radio Tower and Parcel H Areas. This specialized
fingerprinting effort was intended to confirm whether or not the
waste at the Radio Tower and Parcel H Areas was attributable to the
DER site and/or FSR site. The results have indicated that waste
from DER is slightly different in chemical composition than waste
from FSR. The Radio Tower contamination is attributable to the DER
site only. Both sites have contributed to the Parcel H
contamination. Based on the fingerprinting effort, EPA estimates
that 50% of the waste at Parcel H is attributable to each site and
will be addressed as part of each site remedy.
VI. SUMMARY OF SITE RISKS
Human Health Risks
As part of the Remedial Investigation at the DER site, a
quantitative risk assessment was performed to estimate human health
risks from the DER site. This section presents a summary of the
Baseline Human Health Risk Assessment for exposure of humans to
contaminants existing within areas of concern at the DER site and
two non-contiguous areas referred to as the Parcel H and Radio
Tower areas. The waste areas do not include contamination in the
buildings and process vessels and tanks of the refinery. However,
potential health effects from potential human exposure to site-
related contaminants in these structures will be similar to those
from exposure to the waste areas and will be addressed
qualitatively.
This ROD does not address the potential contamination of
groundwater due to site-related activities. The shallow aquifer
may be classified as a Class III aquifer (water not suitable for
human consumption). This pathway of potential contamination and
18
-------
the possible human health effects which could result from exposure
is being evaluated, and will be addressed separately by the GOU.
The purpose of the risk assessment was to compile and evaluate
information collected in the site investigation in order to
estimate the upper limit of potential health risk which may be
present at the site. In the evaluation of potential human exposure
scenarios, on-site sampling and analysis results were used in
conjunction with current federal and state guidance documents and
professional judgement to estimate the potential human health risk
attributable to contamination resulting from past site-related
operations.
The "risk" values generated within this human health risk
assessment will reflect the plausible upper limit to the actual
risk of cancer posed by the site under the exposure scenarios
evaluated. These estimates were compared to the EPA's target risk
range of 1 X 10"* to 1 X 10"6 for hazardous waste site remediations.
The NCP stipulates a 1 X 10"* risk level as a point of departure in
risk management. Such estimates, however, do not necessarily
represent an actual prediction of the risk. Non-carcinogenic
impacts are quantified by the "Hazard Index" which is the ratio of
site concentrations of a contaminant of concern to a reference
concentration that causes a non-carcinogenic impact. EPA's
remedial goal is to reduce the "Hazard Index" at a site to less
than l.O.
The values which are calculated in this assessment are considered
representative of the cancer risk posed by the site only in that
they represent estimates of the plausible upper bound limit of what
is most probably the risk range. The true risk within the range of
the upper limit and zero is indeterminable. What is estimated is
the projected reasonable maximum potential additional lifetime
cancer risk and potential for adverse health effects. The
reasonable maximum potential risk is calculated in order to be
health protective ("health protective" assumptions are also
referred to as "conservative" assumptions in risk assessment
terminology). It should be noted that the risk is an additional
risk - it is present in addition to the baseline approximate "1 in
3" chance which humans share of "getting cancer".
Land Use
a) Current Land Use
The former Double Eagle Refinery is located in an industrial area
just south of the Missouri, Kansas and Texas (MK&T) railroad tracks
and west of the Martin Luther King (MLK) Boulevard bridge. The
immediate area of the site and Parcel H are zoned for industrial
use.
The Double Eagle refinery area is enclosed by a fence topped with
barbed wire; however, there is one section were an unused gate is
19
-------
not completely secured. Feral dogs are often seen coming and going
through small holes in the fence. The fence around Double Eagle
serves to deter transients who may inadvertently wander onto the
site. However, anyone determined to trespass on the site, such as
vagrants looking for shelter, could probably gain access. The
Radio Tower and Parcel H areas are not fenced, so access to these
areas is not controlled.
The potential for trespass in this general area is substantial, for
the site is situated immediately south of the MK&T multi-track
railway line. There are two major interstate freeways nearby (1-35
and 1-40). These thoroughfares may increase the prevalence of
transients and vagrants in the area. Transients have been observed
walking on the access road to the site as well as loitering under
the bridge which carries MLK Boulevard over the MK&T railway lines.
There are also signs, such as gathered firewood, that may indicate
"camping" in good weather under the MLK Boulevard bridge. In
addition, the close proximity to a residential area suggests that
children may visit the Parcel H and Radio Tower areas during play
activities.
The refinery area and adjacent areas are for the most part vacant
(i.e., authorized personnel visit the areas once a day), although
structures in the refinery area may provide limited shelter.
Therefore, there is significant potential for a population of
transients to be exposed to contaminants in the waste areas.
Salvage operations of on-site equipment may also create a
potentially-exposed population of workers. However, these workers
would only be exposed to on-site contaminants infrequently during
the work week.
The nearest major surface water body is the North Canadian River,
which is located approximately one half mile south of the site. The
river is on the far side of the raised freeway with no apparent
hydraulic connections to surface drainage features from the site.
b) Future Land Use
Given the current land use patterns, the Double Eagle Refinery site
is likely to remain an industrial site. Three possible scenarios of
usage, not considering remediation of the site, are possible. They
are:
The site remains as an occasional storage area with minimal
renovation of the existing buildings and no change in the
existing lagoons and impoundments.
The existing buildings, vessels and tanks are razed/removed
and no further development is performed.
The existing buildings, vessels and tanks are razed/removed;
new structures are built; and, workers are present at the site
in a normal working environment. Even though this is not
20
-------
likely unless the waste areas are remediated, this scenario
will still be evaluated because it represents a reasonable
possible scenario.
The future use and development of the Parcel H area is somewhat
more uncertain as any development is likely to depend on
remediation of the waste area as well as the "landfill/rubbish"
area. Because the land use surrounding Parcel H is commercial, EPA
expects future land use at Parcel H to be commercial. The Radio
Tower area is adjacent to a commercial use area. Thus, future
commercial development at the Radio Tower field is likely.
In all of the proposed future use scenarios, it assumed that no
specific remediation of the waste material will occur and that
industrial and construction workers will be exposed to the waste
material in each area.
Identification of Chemicals of Concern
The initial Chemicals of Concern (COC's) were the contaminants on
site which were identified as most likely to contribute significant
cancer risks and non-cancer health effects, and to cause a public
health concern. The risk assessment focused on contaminants that
were site-related, but a chemical was included if it materially
contributed to the overall public health impact. Factors such as
frequency of detection, exposure point concentration and human
toxicity dictated which COC's contributed most to the potential
human health risk from exposure to a particular medium of concern.
The DER site was an oil reclamation plant. As such, the major COC's
were expected to be oil-derived contaminants and other materials
(such as lead) associated with motor vehicle products. In general,
the initial COC's were related to this process. Table 1 lists the
initial COC's, and the media in which they were detected. However,
only a few of the chemicals originally identified actually drove
the risk at the DER site. These specific chemicals will be
discussed later in this Section - Human Health Risk
Characterization.
Exposure Assessment
a) Current Exposure Pathways
The following is a summary of the selected exposure pathways for
the current use of the Double Eagle Site and the surrounding area:
Oral/dermal exposure of on-site workers and trespassers to
contaminants in the sludge present in the lagoons/impoundments
and in the soil;
Inhalation exposure of the on-site workers and trespassers to
volatilized contaminants and/or to particulates carrying
21
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.#1
Initial
TABLE
COMPOUNDS OF CONCERN
COMPOUND
CARCINOGENS
Arstntc
Cadmiun
Benzene
Tetrach I oroethy I ene
Trichloroethylene
1.2-Ofehleroethane
Vinyl Chloride
Phthalates
PCBt
Styrene
PAHa
Heptachlor
Chlordane
NON-CARCINOGENS
Antioony
Bariun
Copper
Lead
Manganese
Mercury
Nickel
Zinc
Ketonea
Alkyl Aroma tics
1,1,1-TMchloroethane
Po I ych I or obenzenes
Phenol a
ON-SITE
SLUDGE
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
OFF-SITE
SOIL
X
X
X
X
X
X
X
X
X
X
OFFSITE
HOTSPOT
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
ON-SITE
SURFACE WATER
X
X
X
X
X
X
X
X
X
X
X
X
OFF-SITE
SURFACE WATER
X
X
X
X
AIR
X
X
X
X
X
X
X
X
X
X
X
22
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contaminants;
Direct exposure of on-site workers and trespassers to
contaminants present in the surface waters of the
lagoons/impoundments through accidental exposure;
Oral/dermal exposure of transients and children to the
contaminants present in the soil/sediment surrounding the
site, in the Parcel H tract, and in the Radio Tower tract;
Inhalation exposure of the transients and children to
volatilized contaminants and/or to particulates carrying
contaminants while in the vicinity of the Double Eagle site or
in the Parcel H and in the Radio Tower tracts;
Direct exposure of the transients and children to contaminants
present in the surface water of the Parcel H impoundments
through accidental exposure;
Oral/dermal exposure of transients and children to the
chemicals present in the areas of concern ("hot spot") in the
Parcel H tract and in the Radio Tower tract; and,
Inhalation exposure of the transients and children to
volatilized contaminants and/or to particulates carrying
contaminants in the ambient air while in the vicinity of the
pool and the high school.
Table 2 lists the exposure and intake assumptions for dermal
contact and ingestion of soil/sludge and surface water, for the
current use scenario. Table 3 lists the exposure and intake
assumptions for inhalation, for both the current and future use
scenarios.
b) Future Exposure Pathways
The following is a summary of the selected exposure pathways for
the future use of the Double Eagle site and the surrounding area:
Oral/dermal exposure of on-site workers to contaminants in the
sludge present in the lagoons/impoundments and in the soil;
Inhalation exposure of the on-site workers to volatilized
contaminants and/or to particulates carrying contaminants;
Direct exposure of on-site workers to contaminants present in
the surface water of the lagoons/impoundments through
accidental exposure;
Oral/dermal exposure of construction workers to the
contaminants present in the areas of concern ("hot spot") in
the Parcel H tract and in the Radio Tower tract;
23
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TABLE 2
Double Eagle Site
Exposure and Intake Assumptions for
Dermal Contact and Ingestion of Soil/Sludge and Surface Water
Current Use scenario
__^
Assumption
Duration of Exposure (years)
Dermal Soil Deposition (mg/cm3)
Skin Exposed to Soil (cm3)
Water Ingestion (I/day)
Dermal Exposure to Water (hr/day)
Skin Exposed to Water (cm3)
- ^"\;<^'x-iffi\-;-' ; \ ' - onT-Site At Double'
Dermal Exposure to Soil (day/year)
Dermal Exposure to Water (day /year)
Soil Ingestion (mg/day)
Age Groups
7-11
5
1.4
4676
0.1
4
3392
''ifagler'sj
0
0
0
^H-|^:v £" " -''*.*- '; ' - '; ,off-s,itev^ f", *:
Transient
Dermal Exposure to Soil (day/year)
Dermal Exposure to Water (day/year)
Soil Ingestion (mg/day)
Hot Spot
Dermal Exposure to Soil (day/year)
Soil Ingestion (mg/day)
For All Areas:
Soil Dermal Absorption Factors:
Semivolatile Organics
Volatile Organics
Metals
Gut Absorption Factors:
Metals , Semivolatiles
Volatile Organics
117
39
50
12
50
1.3%
5%
1%
50%
100%
12-17
6
1.4
6255
0.1
4
4905
Dbef r "- "
39
12
50
," * - ,^\ -"
< -' i,"s
117
39
50
12
50
1.3%
5%
1%
50%
100%
by Years
Adult
10
1.4
4300
0.1
4
5190
, *'' \ %
v %
52
12
50
V
-------
TABLE- 3
Double Eagle Site
Exposure and Intake Assumptions for Inhalation
Current and Future Use Scenarios
Age group
:^::^:e^:M*:^::?
7-11
12-17
Adult
"3V S y
.' -% -\ ,"' ^" « ' - '"
7-11
12-17
i\ '" -.. ' ' ', '
18-70
* v ' "" /^ %%
Industrial
Construction
Industrial-Future
A^~ ' <^**'t . "i ,
12-17
Adult
Exposure
Duration
(Years)
'..^'.^^'t^l^f'^.^ '
5
6
10
5
6
% ' * ' '
30
,- " '" ,';'"'' '"
10
1
25
;;> v-s, v- -
6
10
Exposure
Frequency
(Days/yr)
Transient
117
117
117
Wl
Pool/ School , ,>
250
250
ResidentiaT *--
365
= Wbrker:::'l :4'%vl;;
150
250
250
Trespasser: " '
39
52
Respiratory
Volume
(m3/day)
- .\*'. r "-"\'^ ,;-,
4.6
4.6
4.6
- v ; ; f.. .. j^-.
"\^ , - "^ «"*>*
14
14
r \ / \, V-t ;; *' v\~ >;^
27.4
eg-'i-i^i^c^lfffll^;
9
20
20
'>- ' ,/ 4';"
4.6
4.6
Body
Weight
(kg)
x >; -
27
48
70
F£!^-- f i »
&** ' *
27
48
.'r- v ,\,
70
Pfe^;-'^
70
70
70
v v
48
70
Sources: USEPA 1991, USEPA 1989b, Anderson 1984
25
-------
Oral/dermal exposure of industrial workers to the contaminants
present in the soil/sediment surrounding the site, in the
Parcel H tract, and in the Radio Tower tract;
Oral/dermal exposure of transients and children to the
contaminants present in the soil/sediment surrounding the
site, in the Parcel H tract, and in the Radio Tower tract;
Inhalation exposure of transients and children to volatilized
contaminants and/or to particulates carrying contaminants
while in the vicinity of the Double Eagle site, in the Parcel
H tract and in the Radio Tower tracts;
Oral/dermal exposure of transients and children to the
contaminants present in the areas of concern ("hot spot") in
the Parcel H tract and in the Radio Tower tract; and,
Inhalation exposure of the transients and children to
volatilized contaminants and/or to particulates carrying
contaminants in the ambient air while in the vicinity of the
pool and the high school.
Table 3 lists the exposure and intake assumptions for inhalation,
for both the current and future use scenarios. Table 4 lists the
exposure and intake assumptions for dermal contact and ingestion of
surface soil/sludge and surface water, for the future use scenario.
c) Exposure Scenario?
There were three major sets of current exposure pathways utilized
for the risk assessment:
Workers and trespassers exposure to the on-site contaminants;
Transients and children exposure to transported contaminants;
and,
Residents and children exposure to air borne contaminants.
Therefore, the current use scenario includes on-site workers,
transients both on-site and in the immediate vicinity of the site,
and off-site residents. Since the site is only used periodically,
exposure assumptions are based on actual use.
There were five major sets of future exposure pathways utilized for
the risk assessment:
Workers and trespassers exposure to the on-site contaminants
with expanded site operations and no remediation of the areas
of concern;
Transients and children exposure to transported contaminants;
26
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TABLE 4
Double Eagle Site
Exposure and Intake Assumptions for Dermal Contact
and Ingestion of Surface Soil/Sludge and Surface Water
Future Use Scenario
Age Groups by Years
7-11 12-17 Adult I.
Duration of Exposure (years)
Dermal Soil Deposition (mg/cm2)
Skin Exposed to Soil (cm2)
Soil Ingestion (mg/day)
Skin Exposed to Water (cm2)
Water Ingestion (I/day)
Dermal Exposure to Water (hr/day)
On-Site at
Dermal Exposure to Soil (day/year)
Dermal Exposure to Water (day/year)
5
1.4
4676
50
3392
0.1
4
Double
0
0
6
1.4
6255
50
4905
0.1
4
Eagle
0
0
10
1.4
4300
50
5190
0.1
4
0
0
Worker
25
1.4
4300
50
5190
0.1
4
250
12
C . Worker
l
1.4
4300
50
5190
0.1
4
Off -Site :
Transient
Dermal Exposure to Soil (day/year)
Dermal Exposure to Water (day/year)
oil Ingestion (mg/day)
Hot Spot
Dermal Exposure to Soil (day/year)
Soil Ingestion (mg/day)
For All Areas:
Soil Dermal Absorption Factors
Semivolatile Organics
Volatile Organics
Metals
Gut Absorption Factors
Metals, Semivolatiles
Volatile Organics
Sources: Skin surface areas exposed
117
39
50
0
0
1.3%
5%
1%
50%
100%
117
39
50
0
0
1.3%
5%
1%
50%
100%
117
39
50
0
0
1.3%
5%
1%
50%
100%
are from Anderson et
250
12
50
0
0
1.3%
5%
1%
50%
100%
aJ . , (19
250
12
50
12
50
1.3%
5%
1%
50%
100%
84) ; other
parameter values were derived as described in the text.
27
-------
Residents and children to air borne contaminants;
Construction workers engaged in building new facilities on the
Parcel H and Radio Tower areas, and;
Industrial workers employed at these new off-site facilities.
The future use scenario assumes more frequent exposure to on-
site workers based on increased useage of the site. In
addition, industrial redevelopment of the off-site areas is
assumed, based on land use trends (previous section). Off-
site workers were considered under the future use scenario.
Standard default assumptions were utilized for all future
worker scenarios. The residential exposure assumptions are
the same under the future use scenario as under the current
use scenario. These assumptions were identical since the
residents could potentially be impacted via the air pathway,
which remains the same in the absence of any remedial action.
Toxicity Assessment
The objective of the toxicity assessment is to weigh available
evidence regarding the potential for particular contaminants to
cause adverse effects in exposed individuals. Also, the toxicity
assessment provides, where possible, an estimate of the
relationship between the extent of exposure to a contaminant and
the increased likelihood and or severity of adverse effects. The
types of toxicity information considered in this assessment
include the reference dose (RfD) used to evaluate noncarcinogenic
effects and the slope factor to evaluate carcinogenic potential.
RFDs have been developed by EPA for indicating the potential for
adverse health effects from exposure to contaminants of concern
exhibiting noncarcinogenic effects. RfDs, which are expressed in
units of mg/kg-day, are estimates of acceptable lifetime daily
exposure levels for humans, including sensitive individuals.
Estimated intakes of contaminants of concern from environmental
media (e.g., the amount of a 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 and to protect sensitive subpopulations) to
ensure that it is unlikely to underestimate the potential for
adverse noncarcinogenic effects to occur. The purpose of the RfD
is to provide a benchmark against which the sum of the other doses
(i.e. those projected from human exposure to various environmental
conditions) might be compared. Doses that are significantly higher
than the RfD may indicate that an inadequate margin of safety could
exist for exposure to that substance and that an adverse health
effect could occur.
No RfD or slope factors are available for the dermal route of
exposure. In some cases, however, noncarcinogenic or carcinogenic
risks associated with dermal exposure can be evaluated using an
28
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oral RfD or an oral slope factor. Exposures via the dermal route
generally are calculated and expressed as absorbed doses. These
absorbed doses are compared to an oral toxicity value that is also
expressed as an absorbed dose. Toxicity information used in the
toxicity assessment for the Site was obtained from the Integrated
Risk Information System (IRIS). If values were not available from
IRIS, the Health Effects Assessment Summary Tables (HEAST) were
consulted.
For chemicals that exhibit noncarcinogenic health effects,
authorities consider organisms to have repair and detoxification
capabilities that must be exceeded by some critical concentration
(threshold) before the health is adversely affected. For example,
an organ can have a large number of cells performing the same or
similar functions. To lose organ function, a significant number of
those cells must be depleted or impacted. This threshold view
holds that exposure to some amount of a contaminant is tolerated
without an appreciable risk of adverse effects.
Health criteria for chemicals exhibiting noncarcinogenic effects
for use in risk assessment are generally developed using EPA's RfDs
developed by the Reference Dose/Reference Concentration ("RfD/RfC")
Work Group and included in the IRIS.
For chemicals that exhibit carcinogenic effects, most authorities
recognize that one or more molecular events can evoke changes in a
single cell or a small number of cells that can lead to tumor
formation. This is the non-threshold theory of carcinogenesis
which purports that any level of exposure to a carcinogen can
result in some finite possibility of generating the disease.
EPA's Carcinogenic Risk Assessment Verification Endeavor (CRAVE)
has developed slope factors (i.e., dose-response values) for
estimating excess lifetime cancer risks associated with various
levels of lifetime exposure to potential human carcinogens. The
carcinogenic slope factors can be used to estimate the lifetime
excess cancer risk associated with exposure to a potential
carcinogen. Risks estimated using slope factors are considered
unlikely to underestimate actual risks, but they may overestimate
actual risks. Excess lifetime cancer risks are generally
expressed in scientific notation and are probabilities. An excess
lifetime cancer risk of 1 x 10"6 (one in one million), for example,
represents the probability that one additional individual in a
population of one million will develop cancer as a result of
exposure to a carcinogenic chemical over a 70-year lifetime under
specific exposure conditions.
Slope factors (SFs) have been developed for estimating excess
lifetime cancer risks associated with exposure to potentially
carcinogenic contaminants of concern. SFs, which are expressed in
units of (mg/kg-day)"1 , are multiplied by the estimated intake of
a potential carcinogen, in mg/kg-day, to provide an upper-bound
estimate of the excess lifetime cancer risk associated with
29
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exposure at that intake level. The term "upper bound" reflects the
conservative estimate of the risks calculated from the SF. Use of
this approach makes underestimation of the actual cancer risk
highly unlikely. Slope factors are derived from the results of
human epidemiological studies or chronic animal bioassays to which
animal-to-human extrapolation and uncertainty factors have been
applied( e.g., to account for the use of animal data to predict
effects on humans).
There are varying degrees of confidence in the weight of evidence
for carcinogenicity of a given chemical. The EPA system involves
characterizing the overall weight of evidence for a chemical's
carcinogenicity based on the availability of animal, human, and
other supportive data. The weight - of- evidence classification is
an attempt to determine the likelihood that the agent is a human
carcinogen, and thus, qualitatively affects the estimation of
potential health risks. Three major factors are considered in
characterizing the overall weight of evidence for carcinogenicity:
(1) the quality of evidence from human studies; (2) the quality of
evidence from animal studies, which are combined into a
characterization of the overall weight of evidence for human
carcinogenicity; and (3) other supportive information which is
assessed to determine whether the overall weight of evidence
should be modified. EPA uses the weight of evidence classification
system to categorize carcinogenicity of contamination as one of the
following five groups:
Group A - Human Carcinogen: This category indicates that there
is sufficient evidence from epidemiological studies to support
a causal association between an agent and cancer.
Group B - Probable Human Carcinogen: This category generally
indicates that there is at least limited evidence from
epidemiological studies of carcinogenicity to humans (Group
Bl) or that, in the absence of adequate data on humans, there
is sufficient evidence of carcinogenicity in animals (Group
B2)
Group C - Possible Human Carcinogen : This category indicates
that there is limited evidence of carcinogenicity in animals
in the absence of data on humans.
Group D - Not Classified: This category indicates that the
evidence for carcinogenicity in animals is inadequate.
Group E - No Evidence of Carcinogenicity to Humans; This
category indicates that there is no evidence for
carcinogenicity in at least two adequate animal tests in
different species, or in both epidemiological and animal
studies.
Several of the initial chemicals of concern have been classified as
potential carcinogens by EPA. Each of these also has been assigned
30
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a carcinogenicity weight-of-evidence category. These chemicals are
presented in Table 5 with their respective Referenced Doses and
Potency Factors.
Human Health Risk Characterization
For all exposure scenarios, the air pathway contributed the
greatest carcinogenic risk and HI. Direct contact to soil/sediment
and sludge also contributed to the carcinogenic risk. Direct
contact to the surface water did not contribute significantly to
the risk. However, the HI do not include the toxic effects of lead
and the potential synergistic effects. These estimates suggest
that the receptors are at hazard from exposure to these chemicals
for potential carcinogenic and toxic effects. The contaminants of
concern which actually drove the carcinogenic risk and/or HI will
be discussed for each pathway.
a) Current Risk Characterization
The estimated overall risks of carcinogenic effects from exposure
to the on-site contaminants for the workers (1.2XKT4) and
trespassers (2.7xlO'5) are greater than the target risk of IxlO"6.
The COCs which drove the risk are Chlorinated Hydrocarbons for the
inhalation pathway and PAHs for the soil contact pathway. The
estimated overall His of non-carcinogenic effects from exposure to
the on-site contaminants for the workers (0.89) and trespassers
(0.23) are less than the target HI of one (1.0).
The estimated overall risks of carcinogenic effects from exposure
to the off-site contaminants for the transient adults (4.8xlO'5),
the 7-11 age group (6.5xlO's) and the 12-17 age group (4.9x10^) are
greater than the target risk of 1x10*. The COCs which drove the
risk are Chlorinated Hydrocarbons for the inhalation pathway and
PAHs for the soil contact pathway. The estimated overall His of
non-carcinogenic effects from exposure to the off-site contaminants
for the adults (0.27), 7-11 age group (0.70), and 11-17 age group
(0.42) are less than the target HI of one (1.0).
The estimated overall risks of carcinogenic effects from exposure
to the off-site contaminants in the air for the nearby residents
(2.1X10'3) and children at the pool and high school (3.1x10-* for the
7-11 age group and 2.1X1Q-* for the 11-17 age group) are greater
than the target risk of IxlO^6. The COCs which drove the inhalation
risk are Chlorinated Hydrocarbons, Heptachlor and Chlordane. The
estimated overall HI of non-carcinogenic effects from exposure to
the off-site contaminants for the resident (3.30) and for children
at the pool and high school (3.00 for the 7-11 age group and 1.7
for the 11-17 age group) are greater than the target HI of one
(1.0). The COCs which contributed to the HI are BTEXs, (Benzene,
Toluene, Ethylbenzene, Xylenes) and Trichloroethane. Particulate
air sampling results for lead were high (17.9 ug/m3) onsite.
However, upwind locations were higher (32 ug/m3). Therefore, it is
unlikely that the risk calculated for children at the pool and the
31
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TABLE
Double Eagle Site
Reference Doses and Potency Factors for Contaminants of Concern
Contaminant
Arsenic
Cadmium
Benzene
Tetrachloroethylene
Tr ichloroethylene
1, 2-Dichloroethane
Vinyl Chloride
Phthalates
PCBs
Styrene
Benzo ( a ) pyrene
Benzo ( a ) anthracene
Benzo ( b ) f luoranthene
Benzo ( k) f luoranthene
Chrysene
Indeno (1,2, 3-cd ) pyrene
Naphthalene4
leptachlor
Chlordane
Antimony
Barium
Copper
Lead
Manganese
Mercury
Nickel
Zinc
Ketones5
Alkyl Benzenes
Dichlorobenzenea
Phenol ( 2 , 4-Dimethy 1 )
1,1, 1-Trichlorethane
RfD(O)
mg/kg-day
1E-3
1E-3
_2
1E-2
-
-
-
2E-2
-
2E-1
4E-3
4E-3
4E-3
4E-3
4E-3
4E-3
4E-3
5E-4
6E-5
4E-4
5E-2
2E-25
NO
1E-1
3E-4
2E-2
2E-1
5E-2
2E+0
9E-2
2E-2
9E-2
RfD(I)
mg/kg-day
ND1
ND
-
ND
-
-
-
ND
-
ND
-
-
-
-
-
-
-
ND
ND
ND
1E-4
ND
ND
1E-4
9E-5
ND
ND
9E-2
2E-1
4E-2
ND
3E-1
Carcinogen
Class
A
Bl
A
B2
B2
B2
A
B2
B2
B2
B2
B2
B2
B2
B2
B2
-
B2
B2
-
-
-
-
-
D
-
-
-
-
-
-
Pf(0)
(mg/kg-day)'
1.8E+0
ND
2.9E-2
5.1E-2
1.1E-2
9.1E-2
1.9E+0
1.4E-2
7.7E+0
3 . OE-2
1.1E+13
1.1E+03
1 . 1E+03
1 . 1E+03
1.1E-13
1.1E+04
-
5E+0
1E+0
-
-
-
-
-
-
-
-
-
-
-
-
-
Pf(I)
(mg/kg-day)'
5.0E+1
6 . 1E+0
2.9E-2
3.3E-3
1.7E-2
-
-
-
-
2.0E-3
6.1E+0
-
-
-
-
-
-
SE+0
1E+0
-
-
-
-
-
-
8.4E-1
-
-
-
-
-
.
RfD(O) - oral reference dose for non-carcrnogeno.c effects
RfD(I) -Inhalation reference dose for non-carcinogenic effects
Pf{O) -Oral potency factor for carcinogenic effects
I) -Inhalation potency factor for carcinogenic effects
l.ND means information not
determined per HEAST (1991)
2.Dash means information
not available
3.From USEPA Region VI, personal
communication.
4. Used us model for non-
carcinogenic effects for
PAHs.
5.MEK used as model for ketones.
32
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high school is attributable to the site, since this location was
the upwind monitoring station.
b) Future Risk Characterization
The estimated overall risk of carcinogenic effects from exposure to
the on-site contaminants for the future workers (S.SxlO"4) is
greater than the target risk of IxlO"6. The COCs which drove the
risk are Chlorinated Hydrocarbons, Benzene, Heptachlor and
Chlordane for the inhalation pathway; and PAHs for the soil contact
pathway. The estimated overall HI of non-carcinogenic effects from
exposure to the on-site contaminants for the workers (2.60) is
greater than the target HI of one (1.0) . The COCs which contributed
significantly to the HI are Alkyl Benzene and Ketones for
inhalation; and Chlorinated Hydrocarbons and PAHs for the soil
contact pathway.
The estimated overall risks of carcinogenic effects for off-site
transient adults and children in the Radio Tower and Parcel H
areas, and off-site residents and school children are the same as
the current exposure scenario. This is assuming no redevelopment
of the off-site areas occurs.
If redevelopment occurs the most reasonable land use would be
industrial, therefore construction workers and full time industrial
workers would be exposed. The estimated overall risk of
carcinogenic effects from exposure to the off-site contaminants for
the construction workers (3.7xlO'5) and for the future industrial
workers (9.3x10"*) is greater than the target risk of IxlO"6. The
COCs which drove the risk are Chlorinated Hydrocarbons and
Heptachlor for the inhalation pathway; and PAHs and PCBs for the
soil contact pathway. The estimated overall HI of non-carcinogenic
effects from exposure to the off-site contaminants for both types
of worker scenarios (1.8) is greater than the target HI of one
(1.0). The COCs which contributed to the HI are Alkyl Benzene,
Ketones, and Chlorinated Hydrocarbons for inhalation.
Qualitative Assessments; Lead was found in high concentrations
throughout the DER site (up to 17,000 mg/kg in some locations. It
was also found at elevated concentrations (up to 1000 mg/kg) in
off-site soil/sediment and waste materials. Since there are no
currently-accepted toxicity criteria, lead was not quantitatively
evaluated; therefore, a qualitative evaluation was necessary.
Lead and its compounds have a wide variety of industrial uses; as
such, lead contamination is widespread in the environment. The
major sources of lead exposure in the environment include releases
from vehicular exhaust (currently being reduced by EPA fuel lead
content regulations); discharges from primary and secondary
smelting operations; leaching from lead pipes and solder into
drinking water supplies; and, ingestion of lead-contaminated paint
chips, house dust, and soil by children.
33
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The toxic effects of lead depend on the specific compound to which
humans are exposed. Generally, organic lead compounds, such as the
gasoline additive tetraethyl lead, are somewhat more toxic than
soluble lead salts, particularly with regard to the central nervous
system. This is apparently due to their higher affinity for
tissues with high lipid content. Less soluble lead compounds may
also be less toxic than soluble salts, on the basis of administered
dose, because of their less efficient absorption into the
bloodstream from the gastrointestinal or respiratory tract.
Lead exposure produces a wide range of adverse effects in humans,
over a wide range of exposures. Lead is known to effect the
hematopoietic system, the kidneys, the peripheral and central
nervous systems, and the reproductive system. Lead compounds have
been found to be mutagenic in several test systems, and have been
found to cause cancer in several animal bioassays.
Children are generally more sensitive to lead exposures than
adults. The principal concern with regard to lead exposures in
young children (under age 6) is the occurrence of impaired
neurological development, which may be associated with a broad
spectrum of neurobehavioral disorders. Originally, it was thought
that such effects occurred at lead exposures associated with a
blood level greater than 35 ug/dl. More recent studies have found
that such effects may occur at much lower blood lead levels,
perhaps as low as 10 ug/dl. EPA currently evaluates lead exposures
in children in reference to the latter benchmark blood-lead level
(10 ug/dl).
EPA has classified lead as a Class B2 carcinogen. A number of lead
compounds have been found to induce elevated cancer incidence in
rats and mice. However, the evidence for the association between
lead exposure and elevated cancer rates in epidemiologic studies of
human populations experiencing high lead exposures is equivocal.
EPA has therefore not derived a cancer potency factor for lead
compounds. The EPA has determined that an RfD would not be
appropriate to protect children from adverse developmental impacts
of lead exposure, due to the complex relationship between lead
exposures by various routes, blood-lead levels, and the occurrence
of adverse effects. Instead, EPA has developed a biokinetic model
for assessing the impacts of multi-route lead exposures on
children's blood-lead levels.
EPA recommends that this model be used for age groups 0 to 6 years
to evaluate the health significance of lead exposures using a
target blood lead level of 10 ug/dl as an indicator of potential
adverse effects. At the DER site this model was considered, but
adapting the model for industrial land use and adult exposures
produced inappropriate or erroneous information. Alternatively,
EPA has provided OSWER (Office of Solid Waste and Emergency
Response) Directive #9355.4-02, which establishes that an excess of
lead in soil of 500 to 1000 ppm is responsible for blood level
increases in children above background levels. The concentrations
34
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at the DER site are of such magnitude that exposure to these
materials is likely to be a cause for concern.
Similarly, the industrial setting of the DER site also presents a
problem in evaluating the air pathway quantitatively. Although the
air pathway contributed the greatest risk and hazard index for
organics detected, a trend is not apparent to suggest that the site
contributes to the ambient air contaminant levels of the
surrounding area. This is due to high gasoline constituent levels
measured upwind of both the DER and FSR sites; probably due to the
areas surrounding both sites being highly industrialized.
Similarly, particulate air sampling results for lead were high
(17.9 ug/m3) onsite. However, upwind locations were higher (32
ug/m3) . Therefore, it is unlikely that the risk calculated for
children at the pool and high school is attributable to the site,
since this location was the upwind monitoring station.
Additionally, a qualitative evaluation was performed for the
existing structures. There are multiple abandoned buildings, tanks
and process vessels on-site which are in various states of
disrepair. In addition, many tanks or vessels are unsecured and
some have fallen over. In short there are multiple physical
hazards on-site. The buildings contain debris much of which is
visibly stained. A friable material originally suspected of being
asbestos was discovered in buildings. It was subsequently
confirmed to be asbestos by testing. The debris has also been
shown to contain asbestos materials, but the full extent of
asbestos contamination is unknown. The current workers, future
workers, and salvage workers face serious hazards from these
circumstances.
Central Tendencies
Based on a February 26, 1992, memorandum from Deputy Administrator
F. Henry Habicht, EPA is required to evaluate both "reasonable
maximum exposure" (RME) and "central tendency" in the risk
assessment at Superfund sites. The exposure assumptions associated
with the RME have been used to estimate the baseline risks and
ultimately the remedial action goals at sites. The "central
tendency" scenario represents the risk from more of an "average"
exposure, compared to a "reasonable maximum" exposure.
A comparison of the differences in the risk assumptions between the
RME and central tendency is shown in Table 6. For the DER site the
central tendency risks would decrease from 1.2x10** to 4xlO~5 for the
current risk and from 8.5x10"* to 2.8x10"* for future risk to onsite
workers.
Uncertainties Associated with the Human Health Risk Calculations
Within the Superfund process, baseline quantitative risk
assessments are performed in order to assess the potential human
health impacts of a given site under currently existing conditions.
35
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TABLE 6
Average or
Central Tendency
Reasonable
Maximum Exposure
Contact Rates (CRV
Water Ingestion Rates
Children (1-6 yrs)
Adults
Workers
Soil Ingestion Rates
Children (1-6 yrs)
Adults
Workers
Fish Ingestion Rates
Adults
Air Inhalation Rates
Children (1-6 yrs)
Adults
0.7 L/day
1.4 L/day
0.7
200 ing/day
100 ing/day
50 rag/day
6.5 g/day
5 cu. in/day
20 cu.m/day
Dermal Exposure
Adherence factor (AF) 0.2 xng/cm2
Absorption factor (ABS) Chemical-specific
Total Surface Area (SA)
Children 7,200 cm2/event'
Adults 20/000 cm2/event
Body Weights fBWl
Children (1-6 yrs) 16 kg
Adult 70 kg
Workers 70 kg
1 L/day
2 L/day
1 L/day
200 ing/day
100 mg/day
50 mg/day
54 g/day
5 cu.m/day (50%)
20 cu.m/day (50%)
1 mg/cm2
Chemical-specific
7,200 cm2/event
20,000 cm2/event
16 kg (50%)
70 kg (50%)
70 kg (50%)
36
-------
Exposure Duration (ED)
Residential
Industrial
Average or
Central Tendency
9 years
9 years
350 days/year
250 days/year
Exposure Frequency fEF)
Residential
Industrial
Averaging Time (AT)
Carcinogenic effects 70 years
Noncarcinogenic effects ED
Reasonable
Maxirouin Exposure
30 years
25 years
350 days/year
250 days/year
70 years
ED
C. References For Central Tendency Exposure Parameters
Concentration Term (C)
Site-specific value
Contact Rates (CR)
Water Ingestion Rates
Children (1-6 yrs)
Adults
Workers
Soil Ingestion Rates
Children (1-6 yrs)
Adults
Workers
Fish Ingestion Rates
Adults
Central Tendency
95% UCL
Basis/Reference
US EPA, 1992a
0.7 L/day
1.4 L/day
0.7
200 mg/day
100 mg/day
50 mg/day
6.5 g/day
37
US EPA, 1989a
US EPA, 1989b
50% Adults
Ingestion Rate
US EPA, 1989C
US EPA, 1989C
US EPA, 1991
US EPA, 1989b
-------
Air Inhalation Rates
Children (1-6 yrs)
Adults
Central Tendency
5 cu. m/day
20 cu.in/day
Dermal Exposure
Adherence factor (AF) 0.2 mg/cm2
Absorption factor (ABS) Chemical-specific
Total Surface Area (SA) '
Children (1-6 yrs) 7,200 cm2/event
Adults
Body Weights
Children (1-6 yrs)
Adult
Workers
20,000 cm2/event
16 kg
70 kg
70 kg
Exposure Duration fED)
Residential 9 years
Industrial 9 years
Freoruencv fEF)
350 days/year
250 days/year
Residential
Industrial
Averaging Time (AT)
Carcinogenic effects 70 years
Noncarcinogenic effects ED
Basis/Reference
US EPA, 1989a
US EPA, 1989a;
US EPA, 1989b
US EPA, 1992b
US EPA, 1989a;
US EPA, 1989b
US EPA, 1992b
US EPA, 1989b
US EPA, 1989b;
US EPA, 1991
US EPA, 1991
US EPA, 1989b
» to residential
US EPA, 1991
US EPA, 1991
US EPA, 1989b
US EPA, 1989b
38
-------
D. Reasonable Maximum Exposure Parameters
Reasonable Maximum
Concentration Term (C)
Site-specific value 95% UCL
Contact Rates fCR)
Water Ingestion Rates
Children (1-6 yrs)
Adults
Workers
Soil Ingestion Rates
Children (1-6 yrs)
Adults
Workers
Fish Ingestion:Rates
Adults
Air Inhalation Rates
Children (1-6 yrs)
Adults
Adults
1 L/day
2 L/day
1 L/day
200 mg/day
100 mg/day
50 mg/day
54 g/day
5 cu. in/day
20 cu.m/day
30 cu.m/day
Basis/Reference
US EPA, 1992a
US EPA, 1989a
US EPA, 1989b;
US EPA, 1991
US EPA, 1991
Average value,
US EPA, 1989c
Average value,
US EPA, 1989C
Average value,
US EPA, 1991
US EPA, 1991
US EPA, 1989a
Average value,
US EPA, 1989a;
US EPA, 1989b
Upper bound #,
US EPA, 1989a;
US EPA, 1989b
39
-------
Reasonable Maximum
Dermal Exposure
Adherence factor (AF) 1 mg/cm2
Absorption factor (ABS) Chemical-specific
Total Surface Area (SA)
Children (1-6 yrs) 7,200 cm2/event
Adults
Body Weights fBW)
Children (1-6 yrs)
Adult
Workers
20,000 cm2/ event
16 kg
70 kg
70 kg
Exposure Duration fED)
Residential 30 years
Industrial
25 years
Exposure Frequency (EF)
Residential 350 days/year
Industrial
50 days/year
Averaging Time (AT)
Carcinogenic effects 70 years
Noncarcinogenic effects ED
Basis/Reference
US EPA, 1992b
Average value,
US EPA, 1989a;
US EPA, 1989b
Average value,
US EPA, 1992b
Average value,
US EPA, 1989b
Average value,
US EPA, 1989b;
US EPA, 1991
Average value,
US EPA, 1991
US EPA, 1989b;
US EPA 1991
US EPA 1991
Average value,
US EPA, 1991
Average value,
US EPA, 1991
US EPA, 1989b
US EPA, 1989b
40
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t
E. References
US EPA. 1989a. Exposure Factors Handbook. EPA/600/8-89/043.
US EPA. 1989b. Risk Assessment Guidance for Superfund, Volume I,
Human Health Evaluation Manual (Part A). EPA/540/1-89/002.
US EPA. 1989c. Interim Final Guidance for Soil Ingestion Rates.
OSWER* Directive 9850.4.
US EPA. 1991. Risk Assessment Guidance for Superfund, Volume I,
Human Health Evaluation Manual, Supplemental Guidance, Standard
Default Exposure Factors. OSWER Directive 9285.6-03.
US EPA. I992a. Supplemental Guidance to RAGS: Calculating the
Concentration Term. Publication 9285.7-081.
US EPA. 1992b. Dermal Exposure Assessment: Principles and
Applications. EPA/600/8-91/011B.
41
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They are performed in order j provide ris.- managers with a
numerical representation of th^ severity of contamination present
at the site, as well as to provide an indication of the potential
for adverse public health effects. There are many inherent and
imposed uncertainties in the risk assessment methodologies.
This section addresses potential sources of uncertainty in the risk
estimates, possible impacts of the various sources of uncertainty
and potential bias in the risk estimates. This discussion provides
a context in which the significance and limitations of the various
results can be better understood to evaluate the overall potential
health impacts of the Double Eagle site.
Significant uncertainties are associated with estimates of
exposures and human health risks presented in the risk assessment.
The uncertainties in these results are unavoidable in that they all
depend, to a greater or lesser extent, upon many technical
judgements and, to a lesser extent, upon imperfect mathematical
models of physical, chemical, and biological processes.
Several techniques have been developed to address these
uncertainties. These techniques include the following:
use of multiple exposure and risk scenarios to illustrate the
range of variability in risk estimates associated with
specific analytical methods and assumptions;
qualitative discussion of the levels of uncertainty associated
with specific models and assumptions, and how they contribute
to uncertainties in the overall assessment; and,
use of probabilistic risk models or formalized sensitivity
analyses which quantify uncertainties in each step of the risk
assessment.
The approach taken in this assessment has been to apply a
combination of the first two methods, multiple exposure and risk
scenarios and qualitative discussions of uncertainty in specific
aspects of the models, to characterize the level of uncertainty
associated with risk estimates. One probabilistic model was
performed to examine the assumptions used in this risk assessment
and to illustrate the uncertainty. Multiple exposure scenarios
have been developed which illustrate the potential range of
exposures that can occur at the site under present and possible
future use. Exposures have been assessed with regard to
individuals in multiple age categories as a means of determining
how physiological and behavioral characteristics of these
populations might affect exposure and dose levels.
The overall strategy employed in assessing exposures has been to
define methods and assumptions in such a way as to develop
reasonable maximum estimates for all of the ma jo assumptions used
in the risk modeling. That is, where there is a . ange of models to
42
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choose from, or a range of parameter values to be used in these
models, the specific models used and parameters chosen are those
which are at the upper-bound of realism and reasonableness, based
upon professional judgement and information available in the
literature. The overall impact of this technique on the assessment
of risks is to generate results which, if assessed in a
quantitative probabilistic way, would lie at the upper end of the
expected probability distribution of risk. It is unlikely that
actual risks calculated for any pathway will exceed those
predicted. For example, if it is assumed that a given risk
estimate is derived from three independent models of contaminant
concentrations, contaminant transport, and dose/risk
characterization, and that the parameter values chosen for use in
each model are at or above the 90-percent upper-bound confidence
interval of their actual expected value, then statistically, the
probability that the resulting risk estimate will exceed
(overestimate) the actual risk will be 99.9 percent. That is,
there would be only a 0.1 percent (one in one thousand) probability
that actual risks will exceed calculated risks.
Ecological Risks
The baseline ecological risk assessment, performed by the EPA,
provides a qualitative evaluation of the environmental risks at the
Double Eagle site. The site ecology was evaluated to determine if
the contamination from the site was causing any significant adverse
ecological impact.
The ecological risk assessment is summarized as follows:
a) Receptor Characterization and Endpoints
Receptor Characterization; Potential environmental receptors
include fish populations in the North Canadian River, woody or
herbaceous (non-woody) plants, birds or mammals feeding on this
vegetation, and animals incidentally using the open water areas
(migratory waterfowl and mammals).
Site visits have resulted in observation of a killdeer with its
nest of eggs on the Fourth Street site. Small tadpoles have been
noted in the larger impoundment on site. Turtles and frogs have
been observed at the Double Eagle site. Rabbits are common in the
area of both sites and egrets and other migratory waterfowl have
been sited at the impoundents on parcel H.
A site survey during collection of samples for the toxicity
testing on Parcel H demonstrated that no minnows were available in
the impoundments that could be collected for bioaccumulation
studies, as originally planned. A black snake, believed to be a
King Snake, of about 6 feet in length was encountered at the Radio
Tower Area.
Impoundments on both sites appear on the National wetlands
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Inventory Maps (NWI) (U.S. Dept. of Interior, Fish and Wildlife
Service, 1989). However, since these NWI maps were developed (the
mapping process began in 1991), site changes have likely occurred.
These maps are based on interpretation of aerial photographs and
not actual site surveys.
The former operations area of the Double Eagle site is categorized
as Palustrine, Unconsolidated Bottom, Permanently Flooded,
Excavated Wetlands ("PUBHx"). The Radio Tower area is categorized
as Palustrine, Scrub-Shrub, Broadleaved Deciduous, Temporarily
Flooded Wetlands (PSS1A).
The Parcel H area incudes three different classification areas:
PUBFx, PUBHx, and Palustrine, Emergent, Semi-Permanently Flooded
Wetlands (PEMF).
Vegetation around open water areas at Fourth Street and Parcel H
appears to consist of grasses, likely to be prairie grass species
rather than wetlands species. The former operations area of Fourth
Street and the Eastern Drainage and Parcel H areas appear to have
grass and shrubby vegetation. They are generally open areas that
might not provide much shelter or food for permanent populations of
wildlife species other than small mammals as mentioned above.
Endpoints; Biological Integrity: An assessment endpoint is the
maintenance of biological integrity (i.e., the maintenance of the
structure and function of aquatic ecosystems). The measurement
endpoints for this assessment endpoint will be "toxicity" as
demonstrated by aquatic toxicity tests. The objective of aquatic
toxicity tests is to estimate the "safe" or "no effect"
concentration which permits the normal propagation of fish and
other aquatic life (U.S. EPA 1988). Toxicity testing assessed the
toxicity of the oily wastes from the site on aquatic life.
b) Toxicological-Response Assessment
Heavy metals, lead and chromium, present long-term threats and
could present a serious environmental effect. Due to the habitat,
impacts on the aquatic environment would be more serious than
effects on the terrestrial environment. Therefore, only aquatic
effects were studied.
Toxicity tests were conducted on water from the Parcel H
impoundments (Bio-Aquatic Testing, 1990), in which Ceriodaohnia
dubia survival and reproduction, Pimeohales promelas larval
survival and growth, and bacterial luminescence (MicroTox tests)
were measured. Results of toxicity tests indicate that impoundment
water could have toxic effects on aquatic life. The maintenance of
biological integrity in these impoundments could be impaired by
site related contaminants.
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c) Exposure Assessment
There is no current drainage connection between the sites and the
North Canadian River, although it should be noted that there was a
connection in the past. Potential impacts of the sites on fish
populations, especially game fish, are not currently an issue given
the assumption that the impoundments- do not support a fish
population. However, other on-site environmental receptors could
be exposed to site related contaminants. These receptors might be
woody or herbaceous (non-woody) plants growing in locations of
relatively high contamination, birds or mammals feeding on this
vegetation, and any organisms (migratory waterfowl and mammals)
incidentally using the open water areas.
d) Risk Characterization
The EPA indicates that environmental receptors, in particular
migratory fowl, could be adversely affected by site related
contaminants. Toxicity tests indicate that the potential for toxic
effects from the Parcel H impoundment water on aquatic life do
exist. The analytical results from surface water samples from the
Parcel H impoundments indicate that the chronic water quality
criteria for copper, and the chronic and acute water quality
criteria for lead were exceeded. Therefore, the maintenance of
biological integrity in these impoundments could be impaired by
site related contamination. In addition, the oily material in the
impoundments at the Double Eagle site could be a toxicological and
physical hazard to wildlife.
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
VH. REMEDIAL ACTION GOALS
Results of field investigations, laboratory test results, and
engineering analyses have identified the following contaminant
source areas on the DER site with associated affected media:
Areas of Concern Media
Sludge Lagoon Surface water, sludge, soil and air
Surface Impoundments Surface water, sediment and air
Spill Areas Soil surrounding process equipment,
and air
Tanks and Process Structures, sludge, soil and
Equipment air
Radio Tower and Soil, surface water and sediment,
Parcel H Areas and sludge
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Principal threat wastes are those source materials considered to be
highly toxic or highly mobile that generally cannot be reliably
controlled and that present a significant risk to human health or
the environment should exposure occur. The principal threats at
the DER site are the acidic sludges and contaminated ponds. These
discrete waste areas present the most significant risk at the site,
due to the potential for exposure to lead through direct contact
and inhalation. The risk is also increased due to the concentrated
nature of the waste which presents a high potential for migration
of contaminants to surrounding areas and the underlying ground
water.
Low level threats are those source materials that generally can be
reliably managed with little likelihood of migration and that
present a low risk in the event of exposure. The low level threats
at the site are the contaminated soils and tar matrices, both on
and off-site. These areas are not as highly mobile as the acidic
sludges and the material in the ponds on-site and the concentration
of contaminants is more dilute which decreases the risk from
potential exposure.
The principal threat at the DER site is posed by direct contact and
inhalation, and potential for migration of contaminants to the
ground water. The remedial objectives are to minimize potential
exposure by direct contact or inhalation, and to reduce the
potential for migration of contaminants into the surface waters and
ground waters.
During the RI/FS project for the DER site, the issues related to
the ground waters beneath the site were acknowledged as complex in
comparison to those issues apparent for the source contamination.
Although shallow and deep wells were installed around the perimeter
of both the DER and FSR sites, the determination of vertical and
lateral migration of contaminants will require further study. The
impact of the migration of contaminants in ground water and surface
water will be addressed in a future ROD, Operable Unit 2
(Groundwater Operable Unit - GOU). This ROD will address the
source of contamination, at the DER site, Operable Unit 1 (Source
Control Operable Unit - SCOU).
As discussed in the Risk Characterization section, the surface
water present at the DER site does not pose a significant threat.
The PAHs, PCBs and lead found in pond sediments and sludges pose
the most significant threat (carcinogenic excess risks) due to
direct contact. The Chlorinated Hydrocarbons, Heptachlor,
Chlordane, BTEXs (Benzene, Toluene, Ethylbenzene, Xylene),
Trichloroethane, Alkyl Benzene and Ketones pose the most
significant threat (carcinogenic excess risks) due to inhalation.
Since the remedial action goal for the DER site is to eliminate or
reduce risk to human health and the environment, target action
46
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levels for soil, sediments, and sludges have been established. As
discussed in the Qualitative Assessment section, the OSWER guidance
was utilized for lead. A target action level of 500 ppm for lead
will be utilized, based on industrial land use for the DER site.
For PCBs, a target action level of 25 ppm corresponds to the Toxic
Substances Control Act cleanup level for industrial land use.
However, the maximum concentration of PCBs detected at the DER site
is much less than this level and therefore already meets the
remedial objectives. For PAHs, a target level of 30 ppm Total
Benzo(a)Pyrene Equivalents has been set. This concentration
represents approximately a 10'5 excess cancer risk and was selected
based on Regional guidance for setting remedial goals for PAHs.
By addressing the source of contamination at the DER site (soils,
sediments, and sludges), the risk associated with the air pathway
will be eliminated. However, short-term risks due to air emissions
during a remedial action will also be addressed by use of Region 6
Standard Operating Procedures (SOP) for air emissions, during
remedial design. The SOP for air emissions is dated November,
1991.
VIP. DESCRIPTION OF ALTERNATIVES
A Feasibility Study was conducted to develop and evaluate remedial
alternatives for the DER site. Remedial alternatives were assembled
from applicable remedial technology process options and were
initially evaluated for effectiveness, implementability, and cost
based on engineering judgement. The alternatives selected for
detailed analysis were evaluated and compared to the nine criteia
required by the NCP. As a part of the evaluation, the NCP requires
that a no-action alternative be considered at every site. The no-
action alternative serves as a point of comparison for the :other
alternatives.
The Remedial Action Goals set for the DER site are the
concentration levels below which the media can be left in-place
without treatment. The descriptions and evaluations of remedial
action alternatives included in this ROD addresses surface
contamination, contamination associated with surface soil and the
material in the impoundments on the main site, soil and sludges in
the Radio Tower area, and contamination on Parcel "H". Ground
water contamination will be investigated separately in the GOU.
Upon completion of this investigation, EPA will propose a plan of
action to address any potential problems from ground water
contamination identifed at the site.
The descriptions and evaluations of remedial action alternatives
are separated into seven alternatives addressing contaminated
sediments, surface soils, suface water, and sludges.
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Remedial Action Alternatives
The remedial action alternatives for the SCOU are presented below
with a description of the common elements contained in each
alternative.
Alternative 1: No Action
Alternative 2: Limited Action
Alternative 3: On-site Stabilization and Capping
Alternative 4: On-site Stabilization and Disposal in an
On-site Landfill
Alternative 5: On-site Stabilization and Disposal in an
Off-site Landfill
Alternative 6: Excavation, On-site Incineration, and Onsite
Capping Ash
Alternat.../e 7: Excavati , Off-site Incineration and
DIE :.sal of Ash
Common Elements
All of the SCOU alternatives, with the exception of Alternative 1,
have the following common elements: site preparation; the
installation of office, storage, and security facilities; the
installation of surface water runoff control measures; installation
and maintenance of warning signs and fencing; placement of a notice
to the property deed warning of site hazards; restoration of the
site surface upon completion of the remedial action; and air
monitoring and dust control to minimize any potential short-term
adverse health effects during the remedial action.
All of the alternatives, with the exception of Alternative 1 and 2,
involve treating and/or containing soils, sediments and sludges
which have contaminant concentrations that exceed remedial goals.
These alternatives were developed to address the specific mixture
of wastes at the DER site. The high concentration of lead at the
site precludes biological treatment as an alternative and increased
the need for air pollution controls and residuals treatment for
incineration. The low organics concentration in the sludges (below
health based cleanup levels) allowed stabilization to occur, as
shown in treatability studies conducted in the feasibilty study.
All costs and implementation times are estimates. The costs have
a degree of accuracy of +50% to -30% pursuant to the "Guidance for
Conducting emedial Investigations and Feasibility Studies Under
CERCLA - I ;rim Final" OSWER Directive 9955.3-01, October 1988.
A brief de;, ription of the se~ n alternatives evaluated to address
contaminated sludges, selime. surface soils, and surface waters
follows:
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Alternative 1: No Action
Alternative 1 is a "no action" alternative for contaminated
sludges, sediments, surface soils, and surface water. This
alternative does not provide a means for source control or the
monitoring of the environmental media to determine if contaminant
releases are occurring.
No action alternatives are normally evaluated to determine what the
threat would be, based on a risk assessment, to human health and
the environment if no further actions were taken. The risk
assessment performed assuming a no action alternative provides a
baseline for the comparison of other alternatives. The no action
alternative would not reduce or eliminate the threat posed by the
contaminants of concern presently on-site; therefore, the remedial
action objectives would not be met. Without enhanced source
control, contaminant releases into the air and groundwater could
occur, potentially endangering human health and the environment.
Although the no action alternative would not reduce the risk from
the site, the NCP requires that the no action alternative be
carried through to the detailed analysis of alternatives. The no
action alternative will therefore be carried through to provide a
baseline of comparison to the alternatives utilizing remedial
action.
There are no costs associated with Alternative 1.
Alternative 2: Limited Action
Ma-for Components of the Limited Action Alternative; Components of
this alternative include: consolidation of approximately 1,200
cubic yards of contaminated waste material from Parcel H, and
approximately 1,500 cubic yards from the Radio Tower area; netting
the ponds on-site to comply with Migratory Bird Act; construction
of security fencing and posting signs around the site; deed notices
to identify material remaining on-site; perpetual operation and
maintenance of the site; and five year reviews of the remedial
action.
Although the site is currently surrounded by a 6 foot high chain-
link fence with three strands of barbed wire, the fence does not
preclude public access adequately. Access restrictions would be
enhanced by the repair of the existing fence with the addition of
a sufficient number of warning signs surrounding the site. This
would restrict access to the site by unauthorized persons and
possibly wildlife inhabiting the surrounding environment. A deed
notice would be filed to notify future land owners of the hazards
associated with this site. The contaminated waste from the Radio
Tower area and 50% of the volume of the waste from the Parcel H
area, which is above the remedial action goals discussed in Section
VII of this ROD, will be consolidated with the contents of the
49
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East/West Lagoon. This operation will eliminate the risk from
exposure to the contaminants of concern and the need for fencing,
deed notification and perpetual maintenance for the Parcel H and
Radio Tower areas. The excavated off-site areas will be backfilled
to grade with clean fill. After consolidation, the on site ponds
will be covered with netting to prevent wildlife from contacting
the contaminated surface water. Netting the ponds would comply
with the Migratory Bird Act, which is considered necessary for
protection of the environment. Perpetual maintenance to ensure the
integrity of the nets and fences onsite would be required.
General Components: The estimated time to implement this remedy is
12 months. The estimated cost associated with implementing
Alternative 2 are: Capital Costs: $150,000; Annual Operation and
Maintenance Costs: $10,000; Present Worth: $300,000.
Alternative 3: On-site Stabilization and Capping
Major Components of the Remedial Alternative. The major features of
this alternative consists of the consolidation of off-site wastes
(as discussed in alternative 2), neutralization of the acidic
wastes and in-situ stabilization of 42,000 cubic yards of material
contaminated above the target levels discussed in Section VII of
this ROD, installation of a Subtitle C cap (approximately 2 acres)
over the treated waste, fencing, warning signs, deed notice,
perpetual maintenance and 5 year reviews. Perpetual maintenance is
required because the waste materials will remain on site as a
result of this remediation effort.
Treatment Components: Alternative 3 utilizes an in-situ
stabilization/ solidification technology as a treatment process for
the waste material. Stabilization/solidification of the waste
materials utilizing commercially available materials such as
flyash, kiln dust or portland cement, will provide a neutralized
end product of sufficient structural strength to support a final
cover system.
Stabilization refers to the transformation of the waste into a form
where chemical reactions, or the potential for chemical reactions,
is eliminated over the long-term. Stabilization would place the
inorganic contaminants, like lead and other heavy metals, in a less
soluble form and therefore, reduce the mobility of the contaminant.
Solidification does not necessarily involve a chemical interaction
between the waste and the solidifying agents, but may mechanically
encapsulate the waste into a monolith. Contaminant migration is
restricted by decreasing the surface area exposed to leaching
and/or by isolating the wastes within an impervious capsule.
Treatability studies conducted as part of the feasibility study
indicate that stabilization/ solidification is an effective
technology for the wastes at the DER site. The results of these
studies are shown in Tables 7 and 8. These results indicate that
following treatment, none of the TCLP chemicals were detected above
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their respective TCLP regulatory levels (40 CFR Part 261.24). The
optimum mixture yielding these results was 150% kiln dust and 10%
lime by weight. The low levels of organic COCs and PCBs allows the
stabilization/ solidification to occur, while immobilizing the lead
as well. This alternative will meet the Remedial Action Goals
byminimizing potential exposure by direct contact or inhalation,
and reducing the potential for migration of contaminants into the
surface waters and ground waters.
Implementation of this alternative will require selective
demolition of above-ground storage tanks adjacent to the East/West
Lagoon. Demolition of this tankage will allow access to the waste
material by sideslope cutback, to a depth of approximately 18 feet,
in the lagoon requiring stabilization/solidification. Contaminated
off-site soils from Parcel H and the Radio Tower areas will be
excavated and consolidated with the lagoon--" materials. In
addition,the contaminated sediments from Impoundments #2-#7, and
soil from the contaminated open areas will--be excavated and
consolidated with the lagoon materials. The stabilization/
solidification process will require the addition of kiln dust and
lime, resulting in an increase of volume of waste to be disposed by
30%. The total volume of treated waste is estimated to be 54,600
cubic yards. There is an acceptable amount of disposal capacity at
the DER site.
Containment Components: Consolidation of adjacent contaminated
soils will allow the stabilization/solidification process te
becentrally located on the lagoon site and reduce the area needed
for disposal. The estimated area necessary for disposal of the
treated waste is 2.4 acres, and will be capped and closed as a RCRA
Subtitle C landfill in accordance with the requirements specified
in 40 CFR 264.310 for landfill closure, which will require a cap to
have a permeability less th"an or equal to the permeability of the
natural underlying soil. 'Closure of the area would also comply
with the State of Oklahoma requirements. The cap will be designed
and constructed to promote drainage, minimize erosion of the cover,
and provide long-term minimization of migration of liquids through
the underlying contaminated soils. Consistent with the
requirements of 40 CFR 264.117, long-term operation and maintenance
(O&M) would be conducted to monitor the ground water around the
landfill and to ensure the integrity of the cap.
The stabilization/solidification process will be performed in-situ
with heavy construction equipment such as a backhoe and proceed
sequentially from one end of the lagoon to the other. Generally,
treatment of the waste material will be performed within the area
of contamination (sludge lagoon) followed by excavation,
stockpiling or placement..in an area previously treated and
excavated to the remedial action objective. Throughout treatment,
a buffer zone will be maintained to separate treated material from
untreated material allowing complete treatment and excavation of
waste material in excess of the treatment standards. The above-
ground containment dikes will be reinforced structurally by the
53
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same stabilization/ solidification process to support the final
cover. Contaminated surface water will be utilized for dust
control and as an admixture with the stabilization/ solidification
reagent(s) to improve mixing efficiency. Capping the site will
eliminate the risk from direct contact and inhalation exposure.
The stabilization process will immobilize the contaminants and
minimize the potential for future ground water contamination.
General Components: The estimated time to implement this remedy
and to meet the cleanup levels is 24 months. The estimated costs
for this alternative are: Capital Costs: $4,900,000; Annual
Operation and Maintenance Costs: $10,000; Present Worth:
$5,100,000.
Alternative 4: On-site Stabilization and Disposal in an On-site Landfill
Major Components of the Remedial Alternative. The major features of
this alternative 4 consists of neutralization of the acidic waste
and immobilization of the inorganic contaminants in place with
stabilization/solidification technology, excavation of the
neutralized waste, construction and placement of approximately
54,600 cubic yards of the treated waste into a new on-site landfill
with a cap system, meeting the requirements of the RCRA Subtitle D
regulations, 40 CFR Part 258, backfilling the excavated areas,
installation of fencing and warning signs, deed notification,
perpetual maintenance and 5 year reviews. Perpetual maintenance is
required because the waste materials will remain on-site as a
result of this remediation effort.
Treatment Components: Alternative 4 utilizes the same
stabilization/ sol dification technology as described under
Alternative 3, however the waste material will be encapsulated in
a new on-site landfill (bottom and cover) constructed meeting the
requirements of the RCRA Subtitle D regulations. The RCRA Subtitle
C cap utilized in Alternative 3 is deleted from this alternative in
favor of the base liner and capping requirements identified under
Subtitle D. The RCRA Subtitle D criteria are typically associated
with municipal solid waste landfills, and is appropriate because
the stabilization process will remove the hazardous characteristics
of the waste.
Upon neutralization of the waste utilizing stabilization/
solidification technology, the resulting waste mass is assumed to
be a nonhazardous waste by not exhibiting the hazardous corrosivity
characteristic or exceeding the limitations identified in the
Toxicity Characteristic Leaching Procedure rule. Treatability
studies, as described in Alternative 3, indicate that
stabilization/ solidification to meet these criteria can be
accomplished. By meeting these two criteria, the waste may be
deposited in a Subtitle D landfill. The alternative description
for the remaining portions of Alternative 4 will apply to this
alternative. However, stockpiling of treated material will be
54
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necessary prior to placement in the landfill.
Containment Components: The additional requirements associated with
this alternative involve the construction of a new on-site landfill
meeting the RCRA Subtitle D requirements identified under 40 CFR
Part 258 (Subpart D). A RCRA Subtitle D landfill incorporates the
use of a composite bottom liner system or an alternate bottom liner
system meeting the performance requirements identified in 40 CFR
Part 258. The RCRA Subtitle D requirements identified under 40 CFR
Part 258 have been approved by EPA. These requirements are not
presently effective, but are expected to be effective before
disposal activities will be accomplished. The State of Oklahoma is
currently seeking approval of their revised Subtitle D permitting
program. A composite liner system consists of two components; the
upper component must be a minimum 30-mil flexible membrane liner,
and the lower component must be of at least a two-foot layer of
compacted soil with a hydraulic conductivity of no more than 1 x
10'7 cm/sec. The composite liner system decreases the potential for
leachate to escape the contained landfill cell.
The cover system will meet the requirements outlined in 40 CFR Part
258.60, Closure and Post-Closure Care, and will be comprised of an
erosion layer underlain by an infiltration layer comprised of a
minimum of 18 inches of earthen material that has a permeability
less than or equal to the permeability of the bottom liner system
or natural subsoils present, or a permeability no greater than 1 x
10'5 cm/sec., whichever is less. Upon completion of the landfilling
operation, the portion of the East/West Lagoon area unused by the
on-site landfill will be backfilled with clean imported fill
material. As previously described under Alternative 3,
contaminated surface water will be utilized in the stabilization/
solidification process.
Implementation of this alternative will require demolition of the
on-site equipment, tankage and structures, to provide sufficient
area for construction of the new landfill cell. Demolition of the
site structures will provide sufficient area to stockpile treated
material prior to construction of the landfill and placement of the
treated material into the landfill. The new landfill cell will
utilize approximately 4 acres, at a depth of 10 feet, with the
bottom of the landfill cell a minimum of 5 feet above the seasonal
high groundwater elevation. Since the depth of the sludge lagoon
is within 5 feet of groundwater, a 5 foot layer of fill material
will be placed in the excavated sludge lagoon area prior to
construction of the landfill. The landfill cover will eliminate
the risk from direct contact and inhalation exposure. The
stabilization process will immobilize the contaminants and minimize
the potential for future ground water contamination.
General Components: The estimated time to implement this remedy and
to meet the cleanup levels is 24 months. The estimated costs
associated with implementing Alternative 4 are: Capital Costs:
$7,100,000; Annual Operation and Maintenance: $10,000; Present
55
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Worth: $7,300,000.
Alternative 5: On-site Stabilization and Disposal in an Off-site Landfill
Major Components of the Remedial Alternative. The major features of
Alternative 5 involves the neutralization of acidic waste and
immobilization of inorganic contaminants in place utilizing
stabilization/solidification technology, excavation and shipment of
approximately 54,600 cubic yards of the non-hazardous waste to a
commercial landfill, and backfilling the excavated area with clean
imported fill material. This alternative would constitute a clean
closure for the site and would not necessitate fencing, warning
signs, deed notices, perpetual maintenance or 5 year reviews.
Containment components: Alternative 5 is the same as Alternative 4,
except this alternative involves disposing the wastes at a
permitted off-site landfill meeting the requirements of RCRA. The
off-site materials at the Parcel H and Radio Tower areas will be
excavated and consolidated with the material in the East/West
Lagoon for treatment. The on-site contaminated materials;
Impoundments #2-#7, and the Contaminated Open Areas, will be
excavated and consolidated in the East/West Lagoon for treatment.
Implementation of this alternative will require selective
demolition of 4 above-ground storage tanks adjacent to the
East/West Lagoon. Demolition of this equipment will allow access
to the waste material by sideslope cutback, to a depth of
approximately 18 feet, in the lagoon requiring neutralization.
Material will be neutralized and stabilized/ solidified to remove
the hazardous corrosivity characteristic of the waste, and
exceedance of the toxicity regulatory limits set in 40 CFR Part
261.24 (Toxicity Characteristics Leaching Procedure). By meeting
these two criteria, the waste may be deposited in an off-site
Subtitle D landfill meeting the RCRA requirements identified under
40 CFR Part 258 (Subpart D). Off-site transportation of the
treated waste will be in accordance with the applicable Department
of Transportation regulations. Waste not treated to remove the
corrosivity or that exceeds the toxicity regulatory limits after
treatment will require disposal at a RCRA Subtitle C facility.
Addition of the neutralizing reagents will increase the volume of
waste material to be disposed by approximately 30%. As previously
described under Alternative 3, contaminated surface water will be
utilized in the stabilization solidification process.
The neutralized and conditioned waste material will be excavated,
loaded on trucks and transported to a permitted off-site facility,
meeting the requirements of a RCRA Subtitle D landfill, and
disposed. Excavated areas on and off-site would be backfilled,
graded, and revegetated. Backfill materials will consist of clean
imported material. The risk from direct contact and inhalation
exposure, and the potential for future ground water contamination
will be eliminated by completely removing the waste from the DER
site.
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General Components: The estimated time to implement this remedy and
to meet the cleanup levels is 24 months. The estimated costs
associated with implementing Alternative 5 are: Capital Costs:
$6,400,000; Annual Operation and Maintenance: None; Present Worth:
$6,400,000.
Alternative 6: Excavation. On-site Incineration, and On-site Capping of Ash
Ma^or Components of the Remedial Alternative; The major features of
this alternative involves the consolidation of off-site waste, as
discussed in previous alternatives, neutralization of acidic waste
in place utilizing stabilization/solidification technology,
treatment of the waste in an on-site incinerator for the
destruction of organics, stabilization and disposal of residual
ash, installation of a RCRA Subtitle C cap, fencing, warning signs,
deed notification, perpetual maintenance and 5 year reviews.
Perpetual maintenance is required because the waste materials
(metals) will remain on site as a result of this remediation
effort.
Treatment Components: Alternative 6 involves the on-site
neutralization, excavation and destuction of the organic
contaminants of the waste material in a transportable on-site
incinerator, on-site stabilization/ solidification and disposal of
the incineration residues and backfill of the unused excavated area
with clean imported fill. Neutralization is required due to the
corrosivity characteristic of the waste and its effect on the
incineration equipment. Operation of the incinerator would be in
accordance with RCRA (40 CFR 264 Subpart 0).
Several forms of transportable incinerators are presently available
for the treatment of CERCLA wastes. Many are equipped with high
efficiency, off-gas scrubbers and particulate removal systems
essential for the compliant treatment of the Double Eagle wastes.
High efficiency emission control systems may be a major factor to
evaluate due to considerable lead contamination. Lead in the
wastes will volatilize at temperatures below those of an operating
hazardous waste incinerator and will be entrained in the off-gas
process stream. High efficiency off-gas scrubbing systems are
capable of precipitating the metal from the gas stream and removing
it as a blowdown solid. The transportable incineration processes
that are applicable for the on-site treatment of the Double Eagle
wastes include rotary kilns, circulating bed combustors and
infrared furnaces. These systems are similar in operational
characteristics as those found at permanent installations. Process
units are skid mounted for transportation and are connected
together when mobilized to the site. Selective demolition and
disposal of on-site equipment and tankage is required to
accommodate a transportable incinerator, off-gas scrubbing system,
blowdown water treatment facilities, materials handling
(pretreatment) units and other ancillary equipment necessary for
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effective and efficient operations. The total area required for
the incinerator and ancillary equipment is approximately 3 acres.
Containment Components: Residues from the incineration process,
including ash and scrubber blowdown solids, would contain
concentrated levels of heavy metals and would therefore, require
stabilization prior to on-site disposal. Based on current analyses
of the Double Eagle wastes, it is estimated that through
incineration, the volume of waste would be reduced to approximately
15,000 cubic yards of residual ash and soil. If a bulking factor
of approximately 30% is assumed for the addition of stabilization
additives, a total of approximately 20,000 cubic yards of material
would be backfilled into the East/West Lagoon excavation.
Additionally, approximately 22,000 cubic yards of clean fill would
be imported in order to restore the Double Eagle site to current
elevations. A RCRA Subtitle C cap would be installed over the
backfilled waste, because of the lack of a bottom liner containment
system beneath the waste. The Subtitle C cap would be designed and
constructed in accordance with the requirements specified under 40
CFR 264. Contaminated surface water and blowdown water from the
scrubber system will be utilized for dust control and as an
admixture with the stabilization/solidification reagent to improve
mixing efficiency. Closure of the site would necessitate fencing,
signs, deed notice, perpetual maintenance and five year reviews.
The landfill cover will eliminate the risk from direct contact and
inhalation exposure. The stabilization process will immobilize the
contaminants and minimize the potential for future ground water
contamination.
General Components: The estimated time to implement this remedy and
to meet the cleanup levels is 24 months. The estimated costs
associated with implementing Alternative 6 are: Capital Costs:
$32,400,000; Annual Operation and Maintenance: $10,000; Present
Worth: $32,600,000.
Alternative 7: Excavation. Off-site Incineration and Disposal of Ash
Ma^or Components of the Remdial Alternative; The major features of
this alternative involves consolidation of waste from Parcel H and
the Radio Tower, as previously discussed, the neutralization of
acidic waste in place utilizing stabilization/solidification
technology, excavation and shipment of neutralized waste to a
commercial facility for the thermal destruction of organic
contaminants, stabilization and disposal of residual ash. The
excavated areas of the site would be backfilled, with clean
imported material. This alternative provides for clean closure of
the site and would not require the items required under Alternative
2, Limited Action.
Treatment Components: Alternative 7 involves the neutralization and
excavation of waste on the Double Eagle site, followed by
transportation to an off-site thermal treatment or energy recovery
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facility. The excavated areas will be filled with clean imported
backfill. Clean closure of the site would not necessitate fencing,
signs, deed notice, perpetual maintenance or a five year review.
Several forms- of thermal destruction are presently available for
the treatment of CERCLA wastes. Numerous facilities exist
throughout the country where both the thermal destruction of the
waste organic constituents and the disposal of the residual ash
could be achieved. Other facilities, although capable of thermally
processing the waste would be required to address the ultimate
disposal of residuals. Operation of the incinerator would be in
accordance with RCRA (40 CFR 264 Subpart O).
Wastes on the Double Eagle site will require pretreatment for
neutralization in order to make them acceptable for off-site
transport and/or to meet the requirements of a thermal treatment or
energy recovery facility. Off-site contaminated soils from the
Parcel H and Radio Tower area, and the on-site contaminated soils
will be consolidated with the waste in the East/West Lagoon.
Soils, sediments and sludges would be neutralized in situ, and then
excavated for loading and transport. Contaminated surface water
will be utilized in the neutralization process. Transportation of
waste materials to a permitted off-site facility will be in
compliance with DOT regulations (i.e., placards, proper shipping
containers, etc.). Selective demolition of on-site equipment and
tankage will be required to implement the neutralization and
excavation operations. Although dependent on the progress of the
neutralization effort, it is estimated that the final excavation
and transport of the waste on the Double Eagle site would take
approximately 6 to 8 months.
Once received at the off-site thermal treatment facility, bulk
waste would be unloaded for temporary RCRA compliant storage or
directly fed to the treatment unit. This alternative also
incorporates co-combustion of the waste, or use of the waste as
fuel in devices whose primary purpose is energy production, such as
boilers, furnaces, and process heaters. The thermal treatment
processes provide high temperature destruction of organics in the
waste and scrubbing of the combustion gases. The thermal treatment
processes that are applicable for the treatment of the Double Eagle
waste include rotary kilns, pyrolysis, circulating bed combustors,
infrared furnaces and some industrial installations (boilers, kilns
and furnaces). Thermal destruction is a treatment process sqpiloyad
to destroy organic contaminants in liquid, gaseous and solid waste
streams. Thermal treatment will not destroy inorganic contaminants
such as lead, therefore, the ash residue must be stabilized prior
to disposal.
The operation of a thermal system results in generation of
residual/effluent streams consisting of ash, decontaminated soils
(if soils are present in the feed stream), scrubber water or
blowdown, and flue gases. A detailed waste analysis is required
before a waste is accepted by a treatment/disposal facility. Among
the most important factors which a facility owner considers in
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determining the suitability of wastes for thermal treatment
include: BTU content of the waste, viscosity, water content,
halogen content and ash content.
Containment Components: Based on current analyses of the Double
Eagle wastes, it is estimated that through thermal treatment the
volume of waste would be reduced to approximately 20,000 cubic
yards of residual ash, soil and bulking reagent. Because of the
heavy metal (lead) content of these residuals and solids generated
from the facility's air pollution control system, stabilization
would be required prior to final disposition in a landfill. The
treated material would have to meet the TCLP requirements
previously discussed prior to landfill disposal. Several
alternative thermal destruction options are available for the waste
at the Double Eagle site. The risk from direct contact and
inhalation exposure, and the potential for future ground water
contamination will be eliminated by completely removing the waste
from the DER site.
General Components: Th estimated time to implement this remedy and
to meet the cleanup levels is 12 months. The estimated costs
associated with implementing Alternative 7 are: Capital Costs:
$23,900,000; Annual Operation and Maintenance: None; Present Worth:
$23,900,000.
IX. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The EPA uses nine criteria to evaluate alternatives for addressing
a Superfunc ite. These nine criteria are categorized into three
groups: thre old, primary balancing, and modifying. The threshold
criteria must, be met in order for an alternative to be eligible for
selection. The primary balancing criteria are used to weigh major
tradeoffs among alternatives. The modifying criteria are taken
into account after state and public comment is received on the
Proposed Plan of Action.
Nine Criteria
The nine criteria used in evaluating all of the alternatives are as
follows:
a) Threshold Criteria
Overall Protection of Human Health ?.nd the Environment addresses
the way in wich an alternative would reduce, eliminate, or control
the risks posed by the site to human health and the environment.
The methods used to achieve an adequate level of protection vary
but may include treatment and engineering controls. Total
elimination of risk is often impossible to achieve. However, a
remedy must minimize risks to assure that human health and the
environment are protected.
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Compliance with ARARs. or "applicable or relavent and appropriate
requirements", assures that an alternative will meet all related
federal, state, and local requirements.
b) Primary Balancing Criteria
Long-term Effectiveness and Permanence addresses the ability of an
alternative to reliably provide long-term protection for human
health and the environment after the remediation goals have been
accomplished.
Reduction of Toxicity. Mobility, or Volume of Contaminants through
Treatment assesses how effectively an alternative will address the
contamination on a site. Factors considered include the nature of
the treatment process; the amount of hazardous materials that will
be destroyed by the treatment process; how effectively the process
reduces the toxicity, mobility, or volume of waste; and the type
and quantity of contamination that will remain after treatment.
Short-term Effectiveness addresses the time it takes for remedy
implementation. A potential remedy is evaluated for the length of
time required for implementation and the potential impact on human
health and the environment during implementation.
Implementabilitv addresses the ease with which an alternative can
be accomplished. Factors such as availability or materials and
services are considered.
Cost (including capital costs and projected long-term operation and
maintenance costs) is considered and compared to the benefit that
will result from implementing the alternative.
c) Modifying Criteria -r
State Acceptance allows the state to review the proposed plan and
offer comments to the EPA. A state may agree with, oppose, or have
no comment on the proposed remedy.
Community Acceptance allows for a public comment period for
interested persons or organizations to comment on the proposed
remedy. EPA considers these comments in making its final remedy
selection. The comments are addressed in the responsiveness
summary which is a part of this ROD.
Comparative Analysis
The following discussion provides the comparative analysis for each
of the nine criteria:
1. Overall Protection of Human Health and the Environment
All of the alternatives, except No Action, will provide some degree
of overall protection of human health and the environment. The
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degree to which each alternative provides this protection is
discussed below.
The No Action alternative provides no increase in the overall
protection to human health and the environment. Under this
alternative, all of the potential risks to human health and the
environment associated with the DER site would remain.
Alternative 2, Limited Action, will eliminate the risk associated
with the contaminated material in the Radio Tower area and Parcel
"H" since this material will be excavated, placed on site and
replaced with clean fill. Direct contact with material on-site
will be reduced as long as the fences are maintained trespassers
are kept away from the site. The risk associated with potential
air emissions will not be reduced, nor will this alternative
address the potential risk to future workers on-site.
Alternative 3, On-site Stabilization/ On-site Capping, will
eliminate the off-site direct contact risk from the Radio Tower
area and Parcel H similarly to the Limited Action Alternative.
This alternative will also reduce the risk from direct contact with
the sludges and soils onsite by covering the stabilized material
with a cap. The cap will also eliminate the potential for air
emissions from the site. Some risk from direct contact and
migration to the ground water may remain from possible failure of
the cap; however, the potential for failure would be minimized by
proper annual maintenance.
Alternative 4, On-site Stabilization/On-site Landfill Disposal,
offers levels of overall protection similar to the capping
alternative. However, this alternative provides an additional
level of protection to the ground water by the construction of a
liner beneath the stabilized material. This liner will minimize
the possibility that contaminants can migrate to the ground water
under the site.
The On-site Stabilization/Off-site Landfill Disposal and Off-site
Incineration alternatives, Alternatives 5 and 7, provide
protection of human health and the environment by the ultimate
removal of the contaminated material from the site. Because the
material would be removed, the potential for migration to ground
water and for air emissions would be eliminated.
The risk associated with contact with material in the Radio Tower
area and Parcel "H" will be eliminated by Alternative 6, since this
material will be excavated and replaced with clean soil. The risk
associated with exposure to the organic contaminants will be
eliminated by destruction of these contaminants. Exposure to lead
on the Double Eagle property will be reduced by this alternative by
the stabilization and capping of the metal-contaminated ash from
the incinerator.
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2. Compliance with Applicable or Relevant and Appropriate
Requirements (ARARS)
Contaminated material stabilized on-site will have to be treated to
the extent that it is no longer considered a RCRA characteristic
hazardous waste (40 CFR 261). All of the stabilization
alternatives will attain this degree of treatment. The
alternatives involving incineration will be required to meet the
standards set by the federal government for the operation of
hazardous waste incinerators (40 CFR 264 Subpart O) . The
alternatives involving landfill disposal will be required to meet
the standards for landfill construction and operation set by the
federal government (40 CFR 264 Subpart N).
3. Long-term Effectiveness and Permanence
The No Action and Limited Action alternatives would not provide
long-term effectiveness or a permanent solution to potential risks
associated with material onsite. However, Limited Action would
eliminate the risks at the Radio Tower area and Parcel "H", by
excavating the contaminated material in these areas and backfilling
with clean soil.
Alternative 3 provides a higher degree of long-term effectiveness
and permanence by physically and chemically binding the
consolidated waste material into a stabilized mass, and covering
the treated material with an impermeable cap. The effectiveness
and permanence of this alternative depends on the perpetual
maintenance of the cap. Alternative 4 provides even greater
effectiveness through the construction of a liner to collect any
leachate generated on site, thereby protecting the ground water.
The overall effectiveness and permanence of this alternative also
depends on perpetual maintenance of the cap.
-J
On-site incineration will provide the greatest degree of long-term
effectiveness and permanence, of the on-site alternatives
evaluated, by destroying the organic contaminants in the waste,
eliminating the risk from the polynuclear aromatic hydrocarbons at
the site. Permanence of this alternative will depend on perpetual
maintenance of the cap over the stabilized, metal contaminated
residual from the incinerator.
The Off-site Landfill and Off-site Incineration alternatives
provide the greatest degree of long-term effectiveness and
permanence since the contaminants are removed from the site and no
maintenance actvities would be necessary.
4. Reduction of Toxicity/ Mobility or Volume Through Treatment
The No Action and Limited Action alternatives do not provide any
treatment to reduce the toxicity, mobility, or volume of the
contaminated material. Alternatives 3, 4, and 5 use treatment to
reduce the mobility of the metals and, to a lesser degree, the
mobility of the organic contaminants. The volume of material would
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increase approximately 30%, by the addition of the neutralization/
stabilization reagents. Alternatives 6 and 7 would reduce the
toxicity and volume of contaminated material through the
destruction of the organics. Following treatment of the organic
material, the mobility of lead would be reduced by stabilization of
the ash.
5. Short-Term Effectiveness
There would be no short-term risks associated with construction
under the no action alternative. However, the risks currently
associated with wastes at the site would remain. There would be
potential short-term risks to site workers during the consolidation
of the material from the Radio Tower area and Parcel "H" and from
the transportation of the excavated material to the site area
associated with Alternatives 2, 3, 4, and 6. Some increase in air
emissions may occur because of excavation and during the
stabilization process onsite. However, engineering controls and
monitoring will reduce the potential for any adverse impacts during
implementation of the remedy. Air pollution emissions can be
detected very quickly with standard industrial hygiene monitoring
equipment and visible monitoring. A contingency plan would be
developed to address any potential air emissions during remedial
activities. Alternatives 5 and 7 also have short-term risks
associated with the transportation of wastes to an off-site
facility. These risks can be significantly reduced by a detailed
transportation/ spill prevention plan. The estimated time to
implement Alternatives 3, 4, and 5 is 24 months. The estimated
time to implement Alternatives 2, 6, and 7 is 12 months.
6. Implementability
Treatability studies conducted on material from the DER site
indicate that stabilization (Alternatives 3, 4, and 5) would
effectively immobilize and address the hazardous charateristics of
the contaminated materials at the site. The concentration of
organic chemicals is -efficiently low that stabilization is not
inhibited. The com .ction of a cap (Alternative 3) over the
treated material wou_ :>e easily implemented. Alternatives 5, 6,
and 7 are also easily _..,plementable. However, the implement ability
of Alternatives 5 and 7 will depend upon the availability of
facilities that are compliant with the Superfund Off-site Disposal
Policy. Construction of a landfill on-site (Alternative 4) would
require the demolition of several of the site structures in
addition to the tanks and process equipment. An area to
temporarily stockpile e :avated material during on-site landfill
construction would also .e required.
7. Cost
The present worth cost of the preferred al -native 5 is
$6,400,000. The Limited Action and Onsite Capp^ 3 alternatives
have lower present worth costs of $300,000 and $5,100,000,
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respectively. On-site Treatment and disposal in an on-site
landfill is slightly higher with a cost of $7,300,000. Onsite and
Offsite Incineration are the most expensive alternatives;
$32,600,000 and $29,400,000, respectively.
8. state Acceptance
EPA proposed Alternative 4, Neutralization, Excavation, and On-site
Landfill Disposal as the preferred alternative on July 17, 1992,
the start of the public comment period. EPA also requested the
State of Oklahoma's comments on the alternatives in a letter dated
July 6, 1992. The Oklahoma State Depatment of Health responded
that the State's preferred alternative is Alternative 5,
Neutralization, Excavation, and Off-site Landfill Disposal. The
State of Oklahoma prefers the off-site landfill disposal
alternative because it is $900,000 less costly than EPA's proposed
remedy. Alternative 5 would also have the advantage of saving the
State of Oklahoma the cost of perpetual operation and maintenance
of the site.
9. Community Acceptance
Comments received during the public comment period indicated a
preference for off-site disposal, although one commenter indicated
that off-site incineration was most preferable. Other commenters
suggested that technologies other than landfill disposal and
incineration should be developed. All comments received during the
public comment period and EPA responses are in the attached
Responsiveness Summary.
X. THE SELECTED REMEDY
Based upon consideration of the requirements of Superfund, the
detailed analysis using the nine criteria, and the public comments,
EPA has determined that Alternative 5 - Neutralization, Excavation,
On-site Stabilization, and Off-site Landfill Disposal of the
stabilized material is the most appropriate remedy for the DER
site. The major componenets of this remedy include:
Excavation of the contaminated material in the Radio Tower
area (approximately 1,500 cubic yards) and Parcel "H"
(approximately 1,200 cubic yards)
Consolidation of this material with the contaminated material
on the DER property
- Demolition of onsite structures and disposal of the asbestos
insulation, as necessary
Use of the surface water in the impoundments in the
stabilization process
On-site stabilization of 42,000 cubic yards of the
consolidated material to immobilize and address the hazardous
characteristics of the contaminants
Disposal of the stabilized material in a fully permitted off-
site landfill
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Maintenance of the landfill and ground water monitoring around
the perimeter of the landfill
The principal threat at the DER site is posed by direct contact and
inhalation of contaminants in site soils and sludges, and potential
for migration of lead and PAHs to the ground water. The remedial
objectives are to minimize potential exposure by direct contact or
inhalation, and to reduce the potential for migration of
contaminants into the surface waters and ground waters.
This alternative will significantly reduce the risks from direct
contact with the sludges, soils and sediment at the DER site by
stabilizing and isolating the contaminants in an off site landfill
permitted to accept this type waste. Since all of the material
contaminated above EPA's remedial action goals (lead, 500 ppm;
PAHs, 30ppm; PCBs 25ppm) will undergo treatment and be isolated in
an off-site landfill, the long-term effectiveness is better than
for the stabilization and capping alternative. This alternative
will also comply with all ARARs for stabilization and off-site
landfill disposal. The consolidated material will be stabilized to
ensure that leaching of COCs does not exceed the TCLP regulated
standards listed in 40 CFR 261.24. On-site stabilization and off-
site landfill disposal uses treatment technologies and permanent
solutions to the maximum extent practicable and is cost effective,
offering a degree of protection similar to the incinerati,
alternatives at a lower cost. The selected alternative will also
satisfy the preferences for treatment as a principal element of the
remedy and for on-site remedies written in the Superfund law.
The No Action and Limited Action alternatives (Alternatives 1 and
2) are not being considered at tlvs time because neither
alternative provides for overall protect on of human health and the
environment. The On-site Stabilization/Capping alternative
(Alternative 3) presents technical issues due to the uncertainty of
treating contaminated material near the bottom of the impoundments
onsite without excavation of the material. The selected remedy
does not satisfy the preference in the Superfund law for onsite
remedies. However, it is more cost-effective than the onsite
disposal alternative, and preferred by the State of Oklahoma. The
onsite and off site incineration alternatives (Alternatives 6 and 7)
are much less cost effective than the preferred alternative.
Because each would require stabilization of the incinerator ash
prior to disposal, EPA does not believe that the incinerator
alternatives offer additional protection in line with the
additional cost.
The selected remedy uses treatment and permanent solutions to
address the risks posed by the COCs at the site to the maximum
extent practicable. The selected remedy does not, however, satisfy
the preference in SARA for onsite remedies. EPA's original
proposed plan, Alternative 4, would satisfy this preference in the
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law. However, EPA is deferring its preference in consideration of
public comments and the State of Oklahoma's comments. The selected
remedy will be less costly and not require expenditure of State or
EPA funds for operation and maintenance.
Upon completion of the remedial action, future source control
operation and maintenance activities will not be required, since
all of the wastes will be removed from the site.
XL THE STATUTORY DETERMINATIONS
EPA's primary responsibility at Superfund sites is to select
remedial actions that are protective of human health and the
environment. Section 121 of CERCLA also requires that the selected
remedial action for the site comply with applicable or relevant and
appropriate environmental standards established under Federal and
State environmental laws, unless a waiver is granted. The selected
remedy must also be cost-effective and utilize treatment or
resource recovery technologies to the maximum extent practicable.
The statute also contains a preference for remedies that include
treatment as a principal element. The following sections discuss
how the selected remedies for contaminated soils, sediments and
sludges at the OER site meet the statutory requirements.
Protection of Human Health and the Environment
In order to protect human health and the environment, the
contaminated soils, sediments, sludges, and ground water that
exceed RAOs will undergo a combination of excavation, treatment and
disposal. These media will be treated and contained to meet the
performance standards set forth in this ROD. These performance
standards will assure that site risks fall within the target cancer
risk range of 10"* to 10"6 and the non-carcinogenic hazard index will
be reduced to less than one (1). The performance standards will
also assure that 1) direct contact with contaminated sediments,
sludges, and surface soils will cease, and 2) contaminated
sediments, sludges, and surface soils will cease to act as a source
of ground water contamination.
The selected remedy protects human health and the environment by
reducing levels of contaminants through treatment and disposal. Of
all the alternatives evaluated for the contaminated sediments,
sludges, and soils, the selected alternative provides the best
overall protection to human health and the environment. No
unacceptable short-term risks will be caused by implementing this
remedy.
Compliance with ARARs
The selected sediment, sludge and surface soil remedy, which
utilizes excavation, consolidation, neutralization and
stabilization, and ultimate disposal will comply with all
applicable or relevant and appropriate requirements. The ARARs are
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presented as follows:
Chemical-SpecificARARs for Soils and Sediments
1. Identification and Listing of Hazardous Waste (40 CFR Part
261), Subpart C - Characteristics of Hazardous Haste and Subpart D
- Lists of Hazardous Waste. Applicable because characteristically
hazardous waste will be managed.
2. National Emission standards for Hazardous Air Pollutants (40
CPR Part 61). Relevant and appropriate during excavation,
neutralization and stabilization processes.
3. Air Pollution Permits (Oklahoma Air Pollution Control Rules,
OAC 310:200-7). Applicable during excavation, neutralization and
stabilization processes if emissions exceed one pound per hour for
any one criteria pollutant.
4. Control of Emissions of Organic Materials (Oklahoma Air
Pollution Control Rules, OAC 310: 200-37). May be applicable
depending on the specific air emissions during biotreatment,
neutralization and stabilization processes.
5. Control of Emission of Hazardous and Toxic Air Contaminants
(Oklahoma Air Pollution Control Rules, OAC 310:200-41). May be
applicable depending on the specific air emissions during
excavation, neutralization and stabilization processes.
Action-Specific ARARfor Soils, Sludges and Sediments
standards for owners and Operators of Hazardous Waste Treatment,
Storage, and Disposal Facilities (40 CFR Part 264). Relevant and
appropriate during excavation, neutralization and stabilization
processes.
Cost-Effectiveness
EPA believes that the selected remedy is cost-effective in
mitigating the threat of direct contact with site wastes. Section
300.430 (f) (ii) (D) of the NCP requires EPA to determine cost-
effectiveness by evaluating the following three of the five
balancing criteria to determine overall effectiveness: long-term
effectiveness and permanence, reduction of toxicity, mobility or
volume through treatment, and short-term effectiveness. Overall
effectiveness is then compared to cost to ensure that the remedy is
cost effective. EPA believes the selected remedies meet these
criteria. The estimated present worth cost for the selected SCOU
remedy is $6,400,000.
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Utilization of Permanent Solutions and Treatment or Resource Recovery Technologies to the
Maximum Extent Practicable
EPA believes the selected remedy represents the maximum extent to
which permanent solutions and treatment/resource recovery
technologies can be utilized in a cost-effective manner for the DER
site. Of those alternatives that are protective of human health
and the environment and comply with ARARs, EPA and OSDH have
determined that the selected remedies provide the best balance in
considering long-term effectiveness and permanence; reduction in
toxicity, mobility or volume through treatment; short-term
effectiveness; implementability; and cost, as well as considering
the statutory preference for treatment as a principal element and
considering state and community acceptance.
Preference for Treatment as a Principal Element
The selected remedy satisfies the statutory preference for
treatment as a principal element. The Source Control remedy will
use stabilization/solidification, and neutralization as treatment
methods.
XII. DOCUMENTATION OF SIGNIFICANT CHANGES; A Proposed Plan for
the DER site was released for public comment on July 17, 1992. The
Proposed Plan identified Alternative 4, Consolidation,
Neutralization, On-site Stabilization and On-site Landfill Disposal
as EPA's preferred alternative for soil, sludge, and sediment
contamination. At the same time, EPA requested the preference of
the State of Oklahoma regarding the Proposed Plan. In a letter
dated August 18, 1992, (Attachment C) the OSDH indicated that the
State of Oklahoma preferred Alternative 5 - Consolidation,
Neutralization, On-site Stabilization, and Off-site Landfill
Disposal. OSDH cited the lower cost of the remedy and subsequent
lower State match. As a result of State and general public
comments, EPA has decided to select off-site landfill disposal
rather than onsite landfill disposal for the DER site.
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AITACHMEM1 C
Joan K. Leavitt, M.D. OKLAHOMA STATE.
Commissioner _ DEPARTMENT OF HEALTH
Board of Health 1 QQO ME TENTH
John B. Carmichoel, D.D.S. Gordon H. Deckert, M.D. OKLAHOMA SttpOK
. , ... . , ..
President Dan H. Fieker, D.O. 731 i 7-1299
Ernest D. Martin, R.Ph. Linda M. Johnson, M.D. H4Z/' :" "/: ',- '*
Vice President Walter Scott Mason, III M EOUAl OPPORTUNE EMPLOYER'
Burdge F. Green, M.D. Lee W. Paden
Secretary-Treasurer
August 4, 1992
Mr. Allyn Davis, Director
Hazardous Waste Management Division (6H)
U.S. Environmental Protection Agency
1445 Ross Ave, Suite 1200
Dallas, Texas 75202-2733
Dear Mr. Davis:
This letter is in reply to your letter of July 6,1992. Your letter requests that the Oklahoma
State Department of Health (OSDH) provide comments on the Proposed Plans for the
Double Eagle Refinery and the Fourth Street National Priorities List (NPL) sites. OSDH
prefers the onsite stabilization and neutralization of wastes followed by the disposal in an
offsite commercial landfill as nonhazardous waste. OSDH has no technical objection to the
onsite landfill recommended by EPA, but prefers the offsite landfill because the Feasibility
Study indicates a significantly higher cost for the onsite landfill.
The offsite landfill also has the advantage of saving taxpayers the cost of operation and
maintenance each year. EPA would not be required to conduct five-year reviews of the
remedy because the waste would be removed from the site.
Thank you for your time. If you wish to discuss these matters in more detail please call me at
(405)271-8056.
Sincerely,
Mark S. Coleman, Deputy Commissioner
Environmental Health Services
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