UNITED STATES
PROIIX-TICN AGENCY
PROPOSED PLAN
FOR THE
US ECOLOGY, INC. SITE
SHEFFIELD, ILLINOIS
May 1990
-------
TABLE OF CONTENTS
SECTION
I Statement of Document's Purpose 1
II Site Background 3
III Feasibility Study Surmery 7
IV Summary of Remedial Alternatives 8
Analyzed
Ground-water Remediation 8
Source Control 14
V The Preferred Alternative 20
VI Criteria for Comparison of 24
Alternatives
VII Comparison of Alternatives 26
VIII The Comnunity's Role in the 37
Selection Process
Attachments (9)
Figures
Tables
List of Documents in Repository (partial)
-------
I. STATEMENT OF DOCUMENT'S PURPOSE
An Administrative Order By Consent (Consent Order) was entered into
on September 30, 1985, by the United States Environmental Protection
Agency (U.S. EPA) pursuant to Section 3008(h) of the Resource
Conservation and Recovery Act (RCRA), as amended, 42 U.S.C. §6928(h),
and by US Ecology, Inc. of 9200 Shelbyville Road, Louisville,
Kentucky 40207. The stated mutual objectives of the Consent Order
are: (1) to perform a Remedial Investigation (RI) to determine fully
the nature and extent of the presence or any release of hazardous
wastes and constituents at or from the hazardous waste management
facility owned and operated by US Ecology near Sheffield, Illinois
(the Facility); (2) to perform a Feasibility Study (FS) to identify
and evaluate alternatives for the appropriate extent of corrective
action necessary to prevent or mitigate any migration or release of
hazardous wastes or constituents at or from the Facility; and (3) to
perform any corrective action deemed necessary by the U.S. EPA to
protect human health or the environment. US Ecology is required
under Section VI of the Consent Order to perform all RI/FS work in
conformance with U.S. EPA "Guidance on Remedial Investigations Under
CERCLA," dated May 1985, and U.S. EPA "Guidance on Feasibility
Studies Under CERCLA," dated April 1985. The RI/FS work is required
to be consistent with the guidelines, criteria, and considerations
set forth in the National Contingency Plan (NCP), 40 CFR Part 300.68,
as amended.
-------
-2-
On April 28, 1989, U.S. EPA approved the Revised Final RI Report
submitted by US Ecology. US Ecology submitted a conplete, two volume
report titled "Draft Feasibility Study For Groundwater Remediation
For the Sheffield Hazardous Waste Disposal Sites." It was received
by U.S. EPA on July 6, 1989. On September 1, 1989, U.S. EPA received
another report from US Ecology titled "Draft Feasibility Study For
Source Control For the Sheffield Waste Disposal Sites."
Section 117(a) (42 U.S.C. §9617(a)) of the Comprehensive
Environmental Response, Compensation, and Liability Act (CERGLA), as
amended by the Superfund Amendments and Reauthorization Act of 1986,
requires publication of a notice and a brief analysis of the Proposed
Plan for site remediation. The Proposed Plan must also be made
available to the public for conment. In general, the Proposed Plan
will: (l) provide background information on the site; (2) describe
the alternatives considered for the site; (3) present the rationale
for identification of a preferred alternative for the site; and (4)
outline the public's role in selection of a site remedy.
This Proposed Plan, hereafter referred to as "Plan", is issued to
describe proposed corrective action alternatives for the US Ecology,
Inc. facility located near Sheffield, Illinois (Attachment 1). This
Plan summarizes the alternatives that US Ecology developed and
evaluated further in the two draft FS documents. This Plan also
presents and evaluates the alternative preferred by the U.S. EPA.
The preferred alternative combines control of ground water migration
with control of the contamination source.
-------
-3-
II. SITE BACKGROUND
The US Ecology site is located about three (3) miles southwest of the
town of Sheffield, Illinois in Bureau County. The facility (see
Attachment 2) consists of two presently inactive RCRA hazardous waste
disposal areas: a 5.8 acre hazardous waste disposal landfill (the
Old Site); and a forty (40) acre landfill (the New Site). The rural
area in which the facility is located is zoned primarily for
agricultural use. A 160-acre area located 1500 feet south-southwest
of the site is zoned for recreational use (hunting and camping).
Coal mining activities in the area were discontinued over a decade
ago. Adjacent to the Old Site is an inactive 20.45-acre site zoned
for special use, specifically, low-level radioactive waste disposal
(LLRW site).
US Ecology accepted industrial, laboratory, and agricultural wastes
between 1967 and 1983. Reportedly 4,432,000 cubic feet of various
waste types (93% of it in the New site) are buried in the landfills.
Records indicating waste types accepted for disposal in the Old Site
are fewer and less detailed, generally, than those for the New Site.
Wastes accepted for disposal include, but are not limited to:
paint and paint-related wastes, plating waste, herbicides/pesticides/
insecticides, laboratory wastes, miscellaneous sludges,
polychlorinated biphenyls (PCBs) and PCB-containing and/or
contaminated wastes, printing wastes (inks), miscellaneous solvents
and still bottoms, benzene, xylene, and toluene compounds, acid
-------
-4-
wastes, phenols compounds, hydrocarbons, metal-bearing wastes, and
miscellaneous acids.
The facility was proposed for the CERCLA National Priorities List
(NPL). Because of the Consent Order signed by US Ecology with
U.S. EPA to conduct the Rl/FS activities under RCRA, the facility
was removed from the proposed list in 1989. RI/FS activities were
undertaken to identify the types, quantities, and locations of
hazardous wastes and contaminants on site and to develop ways of
remediating any threat to human health and/or the environment. The
nature and extent of actual or potential site-related contamination
were determined by a series of field investigations including:
0 Geophysical survey
0 Surface and subsurface soil sampling
0 Surface water and ground-water seep sampling and analysis
0 Sediment sampling (at seeps and in Trout Lake)
0 Soil borings and rock corings and associated laboratory
analyses
0 Ground-water monitoring well installation and sampling.
The RI/FS also includes an endangerment assessment performed to
define the threat which the actual or potential site-related
contaminants pose to human health and/or the environment.
The results of the field investigations and laboratory analyses
support the following conclusions:
-------
-5-
1. The ground water has been contaminated by the migration of
hazardous waste and/or hazardous constituents (both organic and
inorganic) from burial trenches in both waste disposal sites (see
Attachment 3):
0 North, east, and southeast of the Old Site (See discussion in
item 3 below);
0 South of the New Site at Trench 18BC (See discussion in item
4 below);
0 Along the north slope of the New Site at the previous location
of monitoring well G-120 and a series of north slope ground-
water seeps (See items 2 and 4 below); and
0 Along the west side of the New Site (indicated in 1987 RI
ground-water sampling results, but not confirmed in 1988
sampling results).
2. Surface water has been affected where contaminated ground water
has discharged to Trout Lake and into a valley along the north
slope of the New Site as seeps. Analytical results from a
surface water sample collected from Trout Lake in April 1989,
(see Soils Addendum to the Final RI) indicated the presence of
tetrachloroethylene (PCE) at a level of 5 micrograms per liter
(ug/1) and detectable amounts of barium and zinc. Surface water
sample analyses from the north slope seeps indicate the release
of both organic constituents (1,2-dichloroethene, chloroform,
trichloroethene (TCE), and PCE) and inorganic constituents
(barium, chromium, zinc, and sulfide).
3. Old Site plume:
Covers about 23 acres in areas north, east, and southeast of
Old Site;
-------
-6-
0 Principal hazardous organic constituents include acetone,
benzene, carton tetrachloride, chloroform, methyl ethyl ketone
(MEK), methylene chloride, and PCE;
0 Inorganic constituents include arsenic, lead, and manga-
nese;
0 Mixes with a plume containing radionuclides that is emanating
from the LLEW site;
0 May be contributing to contamination in the well G-120 area in
the northeast corner of the New Site;
4. New site releases:
0 Trench 18EW3 plume (covers about one acre and contains both
organic and inorganic constituents);
0 North slope seeps (discussed above in item 2);
0 G-120 area (shallow bedrock contamination; organic
constituents detected include TCE, PCE, chloroform, and
dichloroethene);
5. Soil and sediment sampling results (April 1989):
0 Two sediment samples in Trout Lake contained barium at 55
milligrams/kilogram (mg/kg);
0 One sediment sample in Trout Lake detected 2-butanone at
53 ug/kg;
0 North slope: one sediment sample had elevated levels of zinc
and sulfates;
0 Hazardous organic constituents detected in soils (TCE, PCE,
chloroform, toluene, benzene, xylene, dichloroethenes) may
represent compounds that have volatilized from the
contaminated ground water;
0 One Old Site soil sample contained the pesticides dichloro-
diphenol dichloroethane and dichloro-diphenyl-
trichloroethane (ODD and DDT).
The contaminants identified in various environmental media during the
RJ were evaluated to determine the level of risk they pose to
-------
-7-
public health and the environment. The results of the public health
risk evaluation are presented in Attachments 4, 5, 6, and 7.
Exposure assumptions vary for ground water, surface water, and soil
ingestion pathways (see pages 7-23 and 7-24 of the RI and 3-2 of the
Soils Addendum to the RI). The hazard index (HI) indicates a
potential for adverse noncarcinogenic effects when the number is
greater than one. The excess lifetime cancer risk of exposure to
these water and soil sources is expressed in the tables as additional
cancer risks (e.g., 6.0E-03 equals 6.0 x 10~3 which means that the
excess risk is 6 in 1,000). Results indicate the following
contaminant problems present the greatest threat to human health
using the assumptions specified in the Final RI Report:
Carcinogenic risks would be associated with long-term
ingestion of contaminated shallow ground water from both the
New and Old Sites. The risks would be associated primarily
with the presence of PCE, 1,2-dichloroethane, TCE, arsenic,
benzene, chloroform, l,l-dichloroethylene, and methylene
chloride. Contaminated ground water from the bedrock aquifer
at the previous location of well G-120 yields a lower combined
risk to that identified in the Old Site shallow (glacial)
aquifer (i.e., 6.25 x 10~3 versus 1.66 x 10~2).
Noncarcinogenic risk associated with long-term ingestion of
the contaminated shallow ground water would be caused
primarily by TCE, lead, chloroform, methylene chloride, and
PCE.
Surface water originating from ground-water seeps in the north
slope of the New site had levels of 1,2-dichloroethene and TCE
which exceed maximum contaminant levels (MCLs). However,
evaluation of ingestion of surface water resulting from north
slope seepage and water in Trout Lake and other ponds studied
did not result in a determination of adverse effects
(carcinogenic or noncarcinogenic).
III. FEASIBILITY STUDY SUMMARY
During the Feasibility Study (FS), US Ecology identified and
-------
-8-
evaluated a potential list of alternatives that could be used to
remediate the threats and/or potential threats identified at the
site. The original list of alternatives was presented in the
"Preliminary Screening of Remedial Technologies and Development of
Alternatives" dated August 19, 1988. US Ecology further evaluated
alternatives which passed the initial screening and submitted two
separate draft FS documents: one describing alternatives for source
control and one describing alternatives for remediation of ground-
water contamination resulting from releases from the Old and New
Sites. Ultimately, alternatives from both draft FS documents will be
selected and will, in combination, be implemented to address the
environmental and human health threat.
TV. SIFMARY OF REMEDIAL ALTERNATIVES ANALYZED
1. Ground^water Remediation Alternatives
"Die final five alternatives proposed by US Ecology for ground-water
remediation at its Sheffield, Illinois site are briefly described
below:
a. Alternative 1
0 No action
0 Ground-water monitoring
This alternative is required in order to establish a baseline for
comparison with other alternatives. This alternative provides no
control or treatment of the ground water and no further action at
the site to control the source of contamination. It would
-------
-9-
include, however, a long-term ground-water monitoring program.
Signs would be posted along the fence warning of hazardous waste
disposal at the facility. All wastes, routes of contaminant
migration, and human environmental exposure pathways would remain
unchanged. This alternative would not reduce the threats to
human health and/or the environment at the site. Assuming the
ground-water quality does not worsen, Attachments 4, 5, 6, and 7
provide tabular and graphical representation of the health risk
which would result if Alternative 1 were selected.
Estimated Cost
0 Capital Cost: NA
0 Annual O&M Cost: Ground-water monitoring cost
0 Present Worth (30 yrs. 10%) NA
Estimated ftnths to Inplemsit: NA
b. Alternative 2
0 Capping of Old Site
0 Ground-water monitoring
Capping - Under this alternative, US Ecology would place a RCRA-
approved cap over the Old Site (Attachment 3). The cap would be
constructed of natural and/or synthetic materials. The cover
would be designed to be durable and to reduce or eliminate
surface infiltration of precipitation through the hazardous waste
site. The cap would decrease the potential for erosion and
transport of hazardous waste or contaminated soil by air or water
thereby reducing adverse affects due to inhalation and/or dermal
contact.
-------
-10-
Ground-watering monitoring - A long-term ground-water monitoring
program (the same type as in Alternative 1 above) would be
implemented, but no treatment of ground water would be involved.
Estimated Cost
0 Capital Cost: $900,000 (capping cost)
0 Annual O&M Cost: $ 3,000
0 Present Worth (30 yrs. 10%) $928,000
Estimated Months to Implement: 18 months
c. Alternative 3
0 Capping of Old Site
0 Ground-water extraction
0 Ground-water treatment
0 Discharge of treated effluent to surface water
Capping - Same as described in Alternative 2.
Ground-water Extraction System - US Ecology proposes the partial
extraction of contaminated ground water using sixteen (16)
extraction/eductor wells and a subsurface drain system installed
in the Old Site glacial aquifer plume near the source of
contamination. The proposed location of eductor wells and drains
is indicated on Attachment 3. Total flow from the system is
expected to be 100 gallons per minute (gpm). This draft FS
emphasizes ground-water migration control and ground-water
extraction for the Old Site plume, but US Ecology states in
Appendix A of Volume II that "the technologies discussed here
apply to ground water from both the new and old sites."
-------
-11-
US Ecology has proposed the following chemical-specific aquifer
remediation goals for eleven indicator chemicals:
Arsenic: 1.0 micrograms per liter (ug/1)
Benzene: 5.0 ug/1
Chloroform: 5.0 ug/1
1,1-Dichloroethane: 5.0 ug/1
1,2-DichIoroethane: 5.0 ug/1
1,1-Dichloroethylene: 1.0 ug/1
1,2-Dichloropropane: 5.0 ug/1
Methylene Chloride: 5.0 ug/1
Tetrachloroethylene: 5.0 ug/1
Trichloroethylene: 5.0 ug/1
Vinyl Chloride: 1.0 ug/1
US Ecology states in the draft FS for ground-water remediation
(page 2-9) that "these 11 indicator chemicals account for more
than 99 percent of the baseline cancer risk estimate" and "for
approximately 75 percent of the combined hazard index for
noncarcinogenic effects that was determined during the baseline
risk assessment."
US Ecology has estimated that a minimum of thirty (30) years
would be necessary to reduce the levels of contamination in the
ground water to these chemical-specific remediation goals.
Attachment 8 presents graphical representation of the risk US
Ecology estimates would remain if the ground-water contamination
were reduced to the chemical-specific remediation goals proposed
-------
-12-
by US Ecology. For comparison purposes, Attachment 8 indicates
the estimated existing health risk from the Old Site plume which
would continue if no corrective action were taken. In addition,
Attachment 8 indicates the natural background health risks (i.e.,
unrelated to past facility operations) associated with drinking
the ground water. Tnis risk was calculated using ground water
data from the two background wells.
Ground-water Treatment - Following its extraction, the ground
water would be treated as follows:
0 Chemical addition, flocculation, and precipitation (for
removal of metals);
0 Air stripping followed in sequence by activated carbon
adsorption of volatile organic compounds (VDCs) from the vapor
phase in air discharged from the stripper prior to its release
into the atmosphere;
0 Carbon adsorption (as a polishing step, if required) for
removal of base/neutral/acid extractable organics with
discharge of treated water to surface water after achieving
established pretreatment standards; and
0 Disposal of sludge in off-site RCRA landfills.
Ground-Water Mcnitoring - A long-term monitoring program would be
undertaken to note the effectiveness of both ground-water
migration control and the ground-water treatment efforts.
Estimated Cost
0 Capital Costs: $ 2,765,000
0 Annual O&M : $ 852,000
0 Present Worth (30 yrs. 10%) $10,797,000
Estimated Months to Implement: 18 months
-------
-13-
d. Alternative 4
0 Capping of Old Site
0 Ground-water extraction and treatment
0 Discharge of treated effluent to surface water
Capping - Same as described in Alternative 2.
Ground-water Collection System - Same as described in Alternative
3.
Ground-^water Treatment - Under this alternative, the water
treatment process is the same as under Alternative 3 except that
biological treatment replaces the air stripping step.
Neutralized effluent from the metals precipitation step flows to
a trickling filter for treatment of biologically degradable
organics. The biological sludge would be dewatered and the
filter cake hauled off site for incineration.
Ground-water Monitoring - Same as described in Alternative 3.
Estimated Cost
0 Capital Costs: $ 3,143,000
0 Annual O&M costs: $ 1,397,000
0 Present worth (30 yrs. 10%) $16,312,000
Estimated Months to Implement: 18 months
e. Alternative 5
0 Capping the Old Site
0 Ground-water extraction using wells and subsurface drains
0 Treatment of ground water:
- metals precipitation
- biological treatment
-------
-14-
- air stripping
- discharge of treated effluent to surface water
Alternative 5 is the same as Alternative 4 with the exception of
the method of treatment of the extracted ground water. In this
alternative, the effluent from biological treatment is pumped to
an air stripper, rather than to an activated carbon adsorption
column train, for removal of VDCs. The air stream from the air
stripper column is also treated by activated carbon adsorption
prior to release into the atirosphere. As in Alternatives 3 and
4, the treatment plant effluent is to be discharged to a
tributary to lawson Creek about 2000 feet east of the proposed
plant. Gravity would carry the water to its discharge point.
Estimated Cost
0 Capital Cost: $ 3,123,000
0 Annual O&M: $ 612,000
0 Present worth (30 years at 10%) $ 8,892,000
Estimated Months to Inplement: 18 months
2. Source Control Alternatives
a. Alternative 1
0 Capping of the Old Site (extending over the slurry walls)
0 Soil bentonite slurry walls placed:
- Circumferentially around Old Site trenches (Attachment 3)
- Around waste contaminated areas of the New Site near
trenches at 18EWC and G-120 (Attachment 3)
-------
-15-
0 Extension of existing New Site cap at 18EWZ and G-120 over the
slurry walls
0 Extraction wells within Old Site slurry walls (to dewater the
Old Site)
Slurry Walls - Under this alternative, soil bentonite (SB) slurry
walls are installed completely around the Old Site trenches. The
SB slurry walls are projected to have a permeability of 1 x 10~^
centimeters/second, be 2.5 feet wide, extend from the ground
surface to bedrock, and be keyed three (3) feet into bedrock.
Under tnis alternative, SB slurry walls are also to be placed in
semi circular fashion around the extent of the contaminated plume
at the 18EWT trench and around the boundary of trenches 1,2, and
3 of the G-120 areas of the New Site. Ihese two semicircular
slurry walls will tie into existing barrier walls of the New site
and extend downward from ground surface and be keyed three (3)
feet into bedrock.
Capping - This alternative also proposes to place a landfill cap,
meeting RGRA guidance criteria, over the whole Old Site area and
to tie it into the existing New Site cap. Figure 4-1 of the
draft FS for source control indicates that the multilayer cap
will both be in contact at the ground surface with the SB slurry
walls and extend outside beyond the slurry wall (i.e., away from
the buried waste). In addition, the existing New site clay cap
would be extended over the top of the 18EW3 and G-120
contaminated areas enclosed by the slurry walls installed there.
(Note: This alternative assumes that the existing New Site cap
-------
-16-
satisfies RCRA requirements for a hazardous waste landfill cap.
If it does not, IEPA will require that any appropriate
modifications be made.)
Extraction Wells - Alternative 1 places extraction wells within
the Old Site trench area after it is encircled with the SB
slurry wall. Those wells will allow for the removal of existing
contaminated ground water from within the slurry wall and permit
the isolation of the wastes from ground water. Piezometers would
be enployed to monitor the effectiveness of the slurry wall. Ml
of the Old Site and New site wastes will remain at the site under
this alternative.
Estimated Cost
o
Capital Costs: (See ground $1,153,500 (exclusive of Old
water FS for cap costs) Site cap costs)
0 Annual O&M Costs: None listed
0 Present Worth (30 yrs. at 10%) $1,153,500
Time to Implement: Design and contractor procurement = 1 1/2 yrs
Construction time = 1/2 yr.
Total = 2 yrs.
b. Alternative 2
0 Capping of the Old Site (extending over subsurface drains/
trenches)
0 Subsurface extraction trenches:
- circumferentially around Old Site trenches
- around 18EW3 plume
- around plume in G-120 area
-------
-17-
0 Extension of existing New Site cap at 18EW3 and G-120 over
area enclosed by trenches
Capping - Under this alternative, capping for the Old Site and
G-120 and 18BC New Site areas is the same as proposed under
Alternative 1. The only difference is that the capping extends
over extraction trenches rather than SB slurry walls.
Subsurface drains (trenches) - US Ecology proposes the placement
of bio-polymer (BP) interceptor trenches in the same
configuration as the SB slurry walls described in Alternative 1
above. Trenching for installation of the subsurface drains is
done in a manner similar to that for the slurry walls. The
drains are keyed into bedrock three (3) feet. Then a perforated
collector pipe with jump risers is lowered to the trench bottom.
The BP trench is backfilled with coarse gravel and thus
intercepts leachate and ground water allowing extraction and
subsequent treatment. The effectiveness of the trench walls
would be monitored throughout their use. Under this alternative,
excavated soils containing high concentrations of volatile
organic compounds (VOCs) are to be incinerated on site prior to
off-site disposal.
Estimated Cost
0 Capital costs: $10,612,220
0 Annual O&M Costs: $ 3,000
0 Present Worth (30 yrs. at 10%): $10,640,000
-------
-18-
Time to Inplement: Design and contractor procurement =1 yr.
Construction time = 1/2 yr.
Total = 1 1/2 yrs.
c. Alternative 3
0 Capping of Old Site (over slurry walls)
0 Slurry walls around Old Site trenches
0 Subsurface drains/trenches around:
- 18EWZ plume
- G-120 plume
0 Extension of existing New site cap at 18EWZ and G-120 over the
area enclosed by the drains
This alternative simply conbines the slurry walls around the Old
Site from Alternative 1 with the two New Site semicircular
subsurface drain configurations of Alternative 2. All other details
are the same as described previously.
Estimated Cost
0 Capital Costs: $2,193,146
Annual O&M Costs: $ 1,000
Present worth (30 yrs. at 10%): $2,202,000
o
o
Time to Implement: Design and contractor procurement = 11/2
Construction time = 1/2
Total = 2 yrs.
d. Alternative 4
0 Excavation of hazardous waste and contaminated soil from Old
Site trenches
-------
-19-
Qn-site incineration of Old Site waste and soil and disposal
of treatment residue off site
Slurry walls encircling plumes at 18EM: and G-120
Extension of existing cap at 18EWZ and G-120 over areas
enclosed by proposed slurry walls
Slurry Walls and Capping - The placement of slurry walls at 18BC
and G-120 and extension of the existing New Site cap in both
locations is exactly as proposed in Alternative 1.
Excavation of Old Site Trenches - Old Site excavation will entail
removal of all waste from the six disposal trenches and all
contaminated soil to bedrock. All the excavated waste and soil
will be treated by incineration on site. The incinerator, whose
owner or operator would have to obtain a RCRA permit for its
construction and operation, will be a rotary kiln with a 40
ton/hour capacity and will be operated around the clock. The
incinerator will be designed to achieve 99.9999% destruction
efficiency of all combustible constituents. Treated offgases will
corply with all new source performance standards (NSPS) and
prevention of significant deterioration (PSD) requirements.
Incinerator ash will be transported off site for solidification
and disposal.
Estimated Cost
0 Capital Costs: $307,444,986
0 Annual O&M Costs: None listed
0 Present Worth (30 yrs. at 10%): $307,444,986
-------
-20-
Time to Inplement: Design and contractor procurement = 1 1/2 yrs.
Tijne for excavation and disposal = 2 yrs.
Total = 3 1/2 yrs.
V. THE PRKKhKPFTl ALTERNATIVE
1. U.S. EPA's preferred ground-water alternative for ground-water
remediation is one which will:
a. Enploy ground-water pumping to:
i. Limit expansion of the existing contaminated ground water
by hydraulic controls; and
ii. Remove the contaminated ground water from each location of
contamination until ground-water quality at the completion of
the remediation meets the following ground-water protection
standards:
Arsenic: 1.0 ug/1
Benzene: 2.0 ug/1
Chloroform: 0.5 ug/1
1,1-Dichloroethane: 1.0 ug/1
1,2-Dichloroethane: 0.5 ug/1
1,1-Dichloroethylene: 1.0 ug/1
1,2-Dichloropropane: 0.5 ug/1
Methylene Chloride: 5.0 ug/1
Tetrachloroethylene: 0.5 ug/1
Trichloroethylene: 1.0 ug/1
Vinyl Chloride: 1.0 ug/1
-------
-21-
b. Treat the removed ground water as necessary to comply with
applicable State regulatory programs for discharge to air and
surface water; and
c. Provide a ground-water monitoring program to verify progress
toward achieving U.S. EPA's ground-water protection standards.
U.S. EPA has selected the above-listed ground-water protection
standards for the eleven ground-water constituents based on the
practical quantitation limits (PQLs) listed in 40 CFR Part 264,
Appendix IX. By definition, the PQLs "are the lowest concentrations
of analytes in ground waters that can be reliably determined within
specified limits of precision and accuracy by indicated methods
under routine laboratory operating conditions." U.S. EPA has
selected more stringent remediation objectives for all but two of
the eleven constituents (i.e., arsenic and vinyl chloride are the
same as those proposed by US Ecology). The calculated residual
excess cancer risk resulting from extended ingestion of ground water
contaminated with the eleven constituents at the concentrations US
Ecology has proposed for remediation is 1.8xlO~4. This risk is in
excess of the maximum risk range (i.e., 10~6 to 10~4) which U.S. EPA
has established as protective of human health and appropriate for
selecting corrective measures. Attachment 8(a) graphically displays
the carcinogenic risks associated with long-term ingestion of
contaminated ground water from the Old Site plume if:
0 The "No Action" alternative were selected;
0 US Ecology's proposed remediation goals were achieved;
-------
-22-
0 U.S. EPA's ground-water protection standards were achieved;
and
0 Ground water were remediated to background cancer risk levels.
Attachment 8(b) indicates corresponding non-carcinogenic effects.
Conceivably, ground water Alternatives 3, 4, and 5 could, with
modifications, meet all these criteria. Ground water Alternatives
3, 4, and 5 differ only in the manner in which extracted ground water
is proposed to be treated at the surface. Each alternative proposes
the same configuration of extraction wells and subsurface drains.
US Ecology's proposed extraction well system (see Attachment 3) is
insufficient to meet U.S. EPA's preferred alternative. US Ecology
must modify its proposed ground-water extraction and treatment
alternatives to:
0 Include placement of additional extraction wells at or near
plume boundaries which will hydraulically prevent further
migration of contaminated ground water;
0 Provide for individual extraction wells screened in the
glacial aquifer and in the bedrock aquifer (including the
G-120 area), as necessary, to achieve the ground-water
protection standards specified herein in both saturated zones;
0 Specify that extraction of contaminated ground water
will continue until ground-water protection standards are
achieved; and
0 Provide for regular sampling of the extracted ground water
for those radionuclide parameters in Table 5-7 of the RJ plus
1-129. A plan and schedule for these sampling activities
will be required.
2. One preferred source control alternative is Alternative 1
consisting of the following:
-------
-23-
a. Slurry walls around the Old Site trenches;
b. Slurry walls at trench 18QC and the G-120 area;
c. Capping of the Old Site with a RORA-required cap (discussed in
draft FS for ground-water remediation under Alternatives 2, 3,
4, and 5, but considered part of source control) ;
d. Extension of RGRA-required caps over areas encircled by slurry
walls tied into existing barrier walls at 18EW3 and the G-120
area; and
e. Placement of recovery/extraction wells screened near bedrock in
areas encircled by slurry walls (i.e., the Old Site trenches).
The purpose of these wells is to lower the level of the ground
water within the slurry walls to a level below that of the buried
hazardous waste and a high percentage of the contaminated soils.
Alternative 1 for source control needs to be modified to address:
0 Releases of hazardous waste and/or hazardous waste con-
stituents from 18EW3 by repairing or modifying the existing
trench barrier walls;
0 Potential continuing or future releases from the north and
west slopes of the New site. Items can be incorporated into
the future post-closure permit by IEPA which will require
additional leachate control activities in trenches of concern
based on historical ground-water sampling data (i.e. , trenches
1, 2, 3, 23, 24, and 18EW3). Installation of new sumps and/or
extraction wells inside the proposed slurry walled and capped
areas at 18EWZ and G-120 and additional sumps in trenches 1,
2, and 3 would allow interception and removal of more
leachate.
0 Implementation of modifications to the existing New Site clay
cap, if required by IEPA.
Estimated Cost (total for preferred alternative)
-------
-24-
0 Capital Costs: $ 3,918,500
0 Annual O&M Costs: $ 852,000
0 Present Worth (30 yrs. at 10%): $11,950,500
In addition to these costs, the above-listed modifications to the
ground water and source control aspects of this preferred
alternative will add additional costs. However, the additional
expense would not be significant conpared to the overall cost.
Modifications of the existing New Site cap, if necessary, could
potentially increase the total costs significantly.
Tune to Inplement: 2 yrs.
VI. CRITERIA FOR COMPARISON OF ALTERNATIW-S
Each alternative in the draft FS reports was evaluated against the
following list of criteria, as required by the NCP and RI/FS
guidelines.
1. Overall Protection of Human Health and the Environment addresses
whether or not a remedy provides adequate protection and
describes how risks are eliminated, reduced or controlled through
treatment, engineering controls or institutional controls.
2. Compliance with ARARs addresses whether or not a remedy will meet
all of the applicable or relevant and appropriate requirements
(ARARs) of other environmental statutes and/or provide grounds
for invoking a waiver.
3. Long-term Effectiveness and Permanence refers to the ability of a
-------
-25-
remedy to maintain reliable protection of human health and the
environment over time once cleanup goals have been met.
4. Reduction of Toxicity. Mobility or Volume is the anticipated
performance of the treatment technologies a remedy may employ.
5. Short-term Effectiveness involves the period of time needed to
achieve protection and any adverse impact on human health and the
environment that may be posed during the construction and
implementation period until cleanup goals are achieved.
6. Implementabilitv is the technical and administrative feasibility
of a remedy, including the availability of goods and services
needed to implement the chosen solution.
7. Cost includes capital and operation and maintenance costs.
8. State Acceptance indicates whether, based on its review of the
draft FS reports and Proposed Plan, the State of Illinois
concurs, opposes, or has no comment on the preferred alternative.
9. Community Acceptance will be assessed in the responsiveness
summary following a review of the public comments received on the
draft FS reports and the Proposed Plan. The FS documents will be
combined and finalized incorporating the selected corrective
action.
Each alternative was evaluated against these nine criteria. A
discussion of how the preferred alternative compares to the other
alternatives is presented under the following section.
-------
-26-
VII. CCMPARISCN Of ALTERNATIVES
After evaluating the remedial alternative developed in the draft FS
documents in regard to the nine (9) criteria described above, the
U.S. EPA has made a preliminary recommendation that ground water
Alternative 3 and source control Alternative 1 be used to address
contamination at the US Ecology, Inc. landfill. The rationale for
this recommendation is provided below.
1. Overall Protection of Human Health and the Environment:
a. Ground water
Alternatives 1 (the No Action alternative) and 2 do not provide
for the extraction and treatment of contaminated ground water
and, therefore, do not provide for overall protection of human
health and the environment. Alternatives 3, 4, and 5 (as
modified by U.S. EPA) will provide for adequate protection of
human health and the environment since they provide for
remediation of the plumes of contamination by extraction and
treatment of ground water (i.e., from the Old Site, trench 18EW3,
the G-120 area, and the north slope seeps). Following ground-
water remediation to the concentrations proposed by U.S. EPA,
the residual health risks from ingestion of ground water will be
reduced to acceptable levels. Therefore, the preferred
alternative for ground-water remediation can potentially be any
one of Alternatives 3, 4, or 5, as modified. Extraction and
ground-water treatment will continue indefinitely toward
achieving U.S. EPA's ground-water protection standards. A NPDES
permit will restrict the effluent discharge levels of the various
-------
-27-
parameters of concern. Monitoring wells will be sampled
regularly to test for the effectiveness of the extraction and
treatment systems by monitoring for changes in plume size and
contaminant concentrations levels. Because US Ecology owns all
of the land surface under which hazardous constituent plumes are
currently delineated, no third party has a well water supply
screened in a plume. Containment of the plume and extraction and
treatinent of the ground water will reduce or eliminate potential
risks from ingestion of contaminated ground water downgradient of
the landfill at any off-site location.
b. Source control
Alternative 1 is preferred because it is expected to provide an
appropriate degree of overall protection of human health and the
environment by containing (with slurry walls) all Old Site
hazardous wastes and most contaminated soil at the Old Site and
the 18EWT and G-120 areas. The slurry walls will be designed to
be compatible with the chemicals in the buried wastes and will be
constructed to isolate the wastes and contaminated soils and
reduce further contaminant migration to ground water. RCRA-
required caps over the Old and New site and extensions over the
G-120 and 18EWT plume areas will reduce the chance of exposure
to contaminated soil and significantly reduce surface-water
infiltration and leachate generation and help control future
releases of contamination. Extraction wells placed inside the
encircling slurry walls of the Old Site will be designed to
create a reduced hydraulic head ir.side the walls which will
-------
-28-
reduce the probability of contaminated water exiting outward
through the walls; to draw the ground-water surface level down
inside the slurry walls to below the buried waste elevation; and
to transmit extracted ground water to the proposed treatunent
system.
Alternative 2, using subsurface extraction trenches, is judged to
be less effective in isolating or containing the buried hazardous
waste although caps would still be instrumental in reducing
leachate generation. Alternative 3 is slightly less protective
than Alternative 1.
Alternative 4 is intuitively more protective than each of the
other alternatives because the Old Site waste (7% of the total
waste volume at the Facility) would be excavated, treated, and
disposed of off site. However, short-term hazards would be
increased for workers and those living nearby from exhumation
(e.g., potential explosions, increased air emissions, airborne
chemical contaminated particulate matter, etc.), incineration,
and off-site transport of the wastes. By engineering the
effective long-term isolation and containment of the relatively
small volume of the Old Site waste and by reducing the volume of
ground water in contact with the buried waste and contaminated
soil through implementation of Alternative 1, it is felt that
short-term protection is greater and that long-term goals for
protection of human health and the environment will be achieved
as well.
-------
-29-
2. Compliance with ARARs:
a. Ground water
Alternatives 1 and 2 will not attain chemical-specific ARARs
because no extraction and treatment is involved. Alternatives 3,
4, and 5 will meet all the chemical-specific ARARs. Treated
ground water will be discharged to surface water only after
complying with the lEPA-approved NPDES permit. Because the
aquifers are contaminated with multiple chemicals, aquifer
remediation which achieves maximum contaminant levels (M3Ls) is
still insufficiently protective of human health. The additive
health risks necessitate setting cleanup goals, in some cases,
below MZLs. Air emissions related to ground-water extraction and
treatment will be controlled and regulated, as necessary, under
the IEFA air permitting program.
b. Source control
No matter which alternative is chosen, all closure requirements
under PCRA will be included in a closure plan to be approved by
IEFA. Landfill caps will meet RCRA standards. Long-term post-
closure ground-water monitoring and cap maintenance will be
incorporated into a RCRA permit based on standards found at
35 111. Adm. Code Part 724 Subparts F, G, and N.
Capping the landfill (proposed to some degree in each
alternative) will eliminate the potential for exposure
(ingestion, inhalation, or direct dermal contact) to any
contaminated surface soils.
-------
-30-
Air emissions resulting from exhumation and/or trenching
activities (for drains or slurry walls) will be addressed in an
IEFA air permit. Alternative 1 is expected to result in the
fewest emissions and Alternative 4 the most.
3. Long-term Effectiveness and Permanence
a. Ground water
Alternatives 1 (No Action) and 2 (only capping Old Site) will not
provide long-term effectiveness or permanence. Alternatives 3,
4, and 5 appear to provide equal effectiveness and permanence by
extracting and treating the contaminated ground water. The
extraction well system (the same for Alternatives 3, 4, and 5),
as modified, will halt plume expansion and begin and continue
aquifer remediation until ground-water protection standards are
achieved. The remediation by enhanced aquifer purging is
projected to require a minijnum of thirty (30) years whichever
alternative is selected.
Alternative 3 is tentatively recomnended because it does not
utilize biological treatment technology as do Alternatives 4 and
5. Biological systems can be subject to "shock" loads of toxic
organics and to failure of mechanical equipment potentially re-
sulting in destruction of the microorganisms. In addition, as
biological oxygen demand (BCD) levels will be reduced over time
in influent water, nutrient supplements would be required to
sustain the performance of microorganisms thus increasing costs and
the uncertainty of the technology's effectiveness. Therefore, the
-------
-31-
carbon adsorption technology (liquid and vapor phase) used in
Alternative 3 is judged to be more reliable long-term.
b. Source control
Alternatives 1, 2, and 3 propose installation of vertically
positioned containment barriers and FORA-required caps installed
over both the Old and New sites and the 18EW3 and G-120 areas. The
cap design and containment technologies will incorporate details
necessary to achieve the maximum effective lifetimes with the lowest
maintenance. Of these alternatives, Alternative 1 is deemed most
protective.
Alternative 4 will remove all Old Site buried waste and soil to
bedrock, destroy the organics by incineration and dispose of the ash
off site. That would reduce the magnitude of residual risk
somewhat, but estimates indicate that 93% of the buried waste is in
the New Site and, under this alternative, that would still remain
buried on site, but capped.
4. Reduction of Toxicity, Mobility, and Volume
a. Ground water
Alternative 1 and 2 rely on "no action" or capping of the
landfill sites in conjunction with natural attenuation of
contaminated ground water rather than active aquifer purging
activities to reduce toxicity, mobility, or volume. Alternatives
3,4, and 5, as modified, will actively extract the water and
treat it to required ground-water protection standards. The
-------
-32-
draft FS estimates a 98% reduction of the total mass of organic
contaminants in the ground water within thirty (30) years.
b. Source control
Alternatives 1,2, and 3 will adequately contain and isolate the
buried wastes from ground water and reduce the production and
mobility of additional leachate to ground water thereby achieving
the remedial action objectives. Alternative 4 will reduce the
total buried volume of waste by an estimated 7% (i.e., by
exhuming the Old Site), will remove VOCs by soil/waste
incineration, and transport the ash off site for disposal.
Migration of contaminants from the Old Site will be reduced
accordingly.
5. Short-term Effectiveness (including implementation time and
adverse impacts)
a. Ground water
Alternative 1 and 2 provide no effectiveness (i.e., no ground-
water remediation is provided by either). Alternatives 3,4, and
5 would all take eighteen (18) months to implement and are judged
to provide similar levels of short-term effectiveness with -regard
to protection of workers, the community, and the environment
during the construction and implementation stages. Fewer organic
air emissions are anticipated from the implementation of
Alternatives 3 and 5. Alternatives 4 and 5 will produce
biological sludge necessitating additional transport and disposal
activities potentially negatively impacting nearby communities.
-------
-33-
Alternative 3 is tentatively preferred because:
No biological sludge is produced requiring transport and
disposal;
Regenerated activated carbon will reduce overall hazardous
waste generated from treatment and requiring off-site dis-
posal; and
The technology is more reliable.
b. Source control
Alternative 4 is projected to result in adverse noncarcinogenic
and carcinogenic effects to off-site receptors during exhumation
and incineration (about 3 1/2 years). Alternative 2 will involve
incineration of some trenched soil and air emissions of VOCs will
occur during construction activities lasting about 1 1/2 years.
Alternatives 1 is preferred because it produces the least volume
of excavated waste requiring transport and disposal and is
comparable in air emissions and risks with Alternative 3.
Alternatives 1 and 3 would take about two years to implement.
6. Implementability
a. Ground water
Alternatives 1 and 2 are easily inplementable but not
sufficiently protective to consider. All components of the
technologies proposed for Alternatives 3, 4, and 5 (as modified)
are readily available and have been utilized at other sites. The
technologies are reasonably effective, reliable, and employ
standard engineering and construction techniques. None of these
alternatives restrict future modification or expansion of the
-------
-34-
selected grouivi-water remedy if determined to be necessary after
implementation.
The preferred alternative (Alternative 3) is favored because it
incorporates widely used and easily implemented technologies for
treating contaminated ground water (i.e., activated carbon
adsorption and air stripping). Biological treatment, a technical
component of both Alternatives 4 and 5, is more difficult to
implement, has been less widely used, and its performance is
reportedly difficult to predict.
b. Source control
All four alternatives incorporate landfill capping.
Installation of RCRA-required caps and their maintenance is
straightforward.
Slurry walls (Alternatives 1 and 3) and subsurface drains
(Alternatives 2 and 3) are both commonly used technologies and
difficulties in implementation are not anticipated. Both
technologies require care in the design and implementation to
achieve the desired goals of containment or interception of
leachate.
Alternative 4 (exhumation of the Old Site) is a technically
feasible alternative. However, implementation will be more
difficult because of required permits and special equipment for
incineration (in Alternative 2 also), uncertainties and dangers to
workers during exhumation (accurate information on quantities,
-------
-35-
locations, and types of wastes is nonexistent for the Old Site), and
off-site transport and disposal arrangements for the residuals of
treatment (i.e., potential disposal capacity issues and vehicular
accidents).
7. Cost
a. Ground water
Alternative 2 would cost $928,000 over thirty (30) years, but is
insufficiently protective. Of those alternatives implementing
active extraction and treatment of ground water for a minimum of 30
years, Alternative 5 is projected to be the least expensive at
$8,892,000. Alternatives 3 and 4 are $10,797,000 and $16,312,000
respectively.
b. Source control
The cost estimates for capping the Old Site and for maintaining that
cap are projected to be about $928,000 over 30 years for
Alternatives 1,2, and 3.
Alternative 4 is the most expensive to implement at an estimated
$307.5 million. Alternative 2, also incorporating incineration
(i.e., soils excavated from trenches), will cost $10,640,000.
Alternatives 1 and 3 will cost $1,153,500 and $2,202,000
respectively. Alternative 1 is preferred.
8. State Acceptance
The Illinois Department of Nuclear Safety (ITNS) was briefed on
-------
-36-
U.S. EPA's preferred alternative on December 21, 1989. IDNS
concurs with the alternative selected in that:
a. Placing a slurry wall around the Old Site, rather than subsur-
face drains, is anticipated to have a lesser effect on the local
ground-water flow direction associated with the Low-level Radioactive
Waste Site; and
b. Trie alternative will require testing of extracted ground water for
the presence of a specified list of radionuclides and, if any are
detected, appropriate treatment of the water and management of
associated wastes generated.
•Die IEPA, unable to attend the December 1989, meeting, was
briefed on the preferred alternative on February 26, 1990. IEPA
has expressed concerns about the long-term effectiveness and
technical feasibility (because of the depth to bedrock) of
implementation of slurry walls as a component of the preferred
alternative. U.S. EPA will address these aspects of the remedy after
IEFA has had an opportunity to review and cament on other aspects of
the proposed plan during the comment period.
9. Community Acceptance
Acceptance by the community of the preferred alternative will be
evaluated based on comments received at the public hearing on
U.S. EPA's proposed plan and during the formal public contnent
period.
-------
-37-
In summary, based on the information available and analysis of the Final
Remedial Investigation Report and'the two draft Feasibility Study
documents, U.S. EPA proposes that the preferred alternative for the US
Ecology site is consistent with the requirements of RCRA. The
combination of the draft ground water FS Alternative 3 for ground-water
remediation and Alternative 1 from the draft source control FS, along
with the specified modifications listed in Section V, is sufficiently
protective of human health and the environment. Ground-water monitoring,
extended aquifer remediation, containment of buried hazardous waste,
added prevention of leachate generation (to the extent possible) by
capping and collection of any leachate that is generated are the key
components to ensure that the preferred alternative will provide long-
term protection.
VIII. THE (XWUNITY'S ROLF Th} TOF .qFT.fyTTffl PROCESS
To encourage public participation in the selection process, the U.S.
EPA has set a public ccmnent period from May 28 , 1990 , through July 11 ,
1990. Interested parties are requested to comment on the alternatives
presented in this Plan and elaborated upon in the draft FS reports. Tne
RI/FS documents, as well as any other pertinent documents in the
administrative record (e.g., work plans, analytical data, etc.), may be
consulted for the details on the development and evaluation of the
alternatives considered. The documents listed in Attachment 9 to this
Plan are available for public review at the:
Sheffield Public Library
136 East Cook Street
Sheffield, Illinois 61361
(815) 454-2628
-------
-38-
Tne final corrective action remedy for US Ecology's Sheffield facility
will not be selected until the public conrnent period is conpleted and all
cements have been evaluated. Based on new information or public
Garment, U.S. EPA may modify the preferred alternative or select another
response action presented in this Plan and the draft FS documents.
Therefore, the public is encouraged to review and coiment on all the
alternatives considered for the site. Written Garments on this Plan and
the draft FS reports will be accepted throughout the public conment
period. A Responsiveness Sunrnary will be prepared by U.S. EPA which
will address all significant public Garments received during the Garment
period. Inis Responsiveness Summary will be made available to the
public. If the Garments are such that significant changes are made in
the corrective measure alternative identified by U.S. EPA, the Agency
will seek public Garments on the revised corrective measures alternative.
Written Garments should be sent to:
Mr.Jonathan Cooper
IL/TN Technical Enforcement Section, 5HR-12
RCRA Enforcement Branch
U.S. Environmental Protection Agency
230 South Dearborn Street
Chicago, Illinois 60604
Written Garments must be postmarked no later than July 11, 1990. A
public hearing to discuss the Proposed Plan, the Final RI Report, and
the draft FS reports has been scheduled for 7:00 p.m. June 28, 1990, at
the Bureau County Court House in Princeton, Illinois.
Upon consideration of public conment and after the Responsiveness
Summary has been publicly noticed, U.S. EPA will approve a final
-------
-39-
corrective measure alternative for the US Ecology facility in Sheffield,
Illinois.
If anyone has questions regarding the public comnent period or the process,
further information may be obtained from:
Ms. Suzanne Kircos
Community Relations Coordinator
U.S. Environmental Protection Agency
Office of Public Affairs, 5PA-14
230 South Dearborn Street
Chicago, Illinois 60604
(312) 353-3209
Also a toll free number ((800) 572-2515) is available to Illinois residents
between 9 a.m. and 4:30 p.m. on Monday through Friday.
Please be advised that a two-week informational period will precede the
public comment period. This period will extend from May 14, 1990, to May 28,
1990. There will be an informational meeting held at the Buda-Sheffield
Western School cafeteria, Stewart Street, Buda, on June 14, 1990. The
meeting is scheduled to begin at 7 p.m.
-------
ATTACHMENT 1
BUREAU COUNTY
SITE LOCATION MAP
-------
ATTACHMENT 2
$
II ./ /I/
11 / /.
II / L?
II / TROUT <
US ECOLOGY SHEFFIELD HAZARDOUS WASTE DISPOSAL SITES
-------
ATTACHMENT 3
GROUND WATER
SEEPS
m i U.IA—ay
18EWC AREA
LEGEND
SLURRY WALL
CAP/COVER
GROUND WATER CONTAMINATION
(OLD SITE PLUME)
• GROUND WATER EXTRACTION WELLS
PROPOSED PLAN FOR U S ECOLOGY SHEFFIELD SITE
-------
ATTACHMENT 4
Table 7-12. Risk^Assessment Summery fop Chronic Exposure: US Ecology Shefield Facility
s===s=== • --=* ==s========e==s==" = = ======£=sz»»ss=ar*a3s»s*as»*«a»s
Site
Exposure
Pathway
Hazard Index
Noncarcinogenic
Effects:
Confined
Exposure
Excess Lifetime
Cancer Risk:
Contained
Exposure
Old Site: Bedrock
Old Site: Glacial
Mew Site: Bedrock
New Site: Glacial
Trout Lake
North Slope Seeos
Pond/Gravel Pit
CW Ingest ion
GV Ingestion
GU Ingestion
GW Ingestion
SW Ingestion
SW Ingestion
SW Ingestion
1.50E-01
6.58E-01
5.27E*01
3.21E»01
8.38E-04
6.81E-Q3
6.51E-W
1.09E-05
1.66E-02
6.25E-03
4.93E-03
1.02E-07
2.63E-06
O.OOE»00
7-33
-------
ATTACHMENT 5
OCCUN1CS
TABLE 3-1. IISl CM»»ACTEBir»T;o«: IHCESTIOn EXPOSURE TO SU»»»CE SOUS
Oewicel
INOtCANICS
Antimony
Arsenic
Barium
Beryl 1 ium
Cacfnium
Chromium
Cobait
Copper
lead
•ercury
Nickel
Selenium
Tin
Vanadium
Zinc
Man
Dean naiimum Background Chronic Dote Naiard Inde* Excess
Concentration Concentration. Concentration Ingestion Chronic lifetime
in Soil (a) in Soil in Soil (b) Exposure (c) Ciposure Cancer tisk
(*B/kg) (mg/kg) (mg/kg) (ng/kg/day) (Dose/lfD) (Dote i Q'*)
0.473
13.963
8S.7SO
0.645
0.173
16.250
6.419
9.519
6.669
0.014
13.419
0.100
0.061
30.063
32.6Sfl
1.400
21.000
190.000
0.960
0.320
23.000
7.900
13.000
9.300
0.085
18.300
1.600
0.570
44.000
58.000
0.41
8.20
43.00
0.55
0.11
13.00
6.50
12.10
3.35
0.00
15.50
0.32
0.80
18.00
31.50
1.59£-07
t.TOt-06
z.sac-tt
2.171-07
5.8CE-08
5.47E-06
2.161-06
3.20E-06
2.24E-06
4.S4E-09
4.51E-06
1. Jit -08
2.04E-08
1.01E-05
1.10E-05
S. 971-04
4.rt>E-03 8.22E-06
J. 771-04
4.Jtf -05
1.16E-04
J.An-06
I.65E-05
1.60E-03
1.6U-OS
2.26C-04
1.121-CS
3.40E-C8
1.UE-03
5.50E-55
Acetone
Carbon Tetracniorioi*
Chloroform
Hethylene Chloride
Tetrachloroethylene
1,1, 1-Tricfi(oro«tnane
Trichloroethylen*
0.013
0.003
0.280
0.008
0.092
0.002
0.025
0.019
O.OS4
2.600
0.010
1.200
0.019
0.200
0.00
0.00
0.00
0.02
0.00
0.00
0.00
4.291-09
1.14E-09
9.42E-OJ
2.69E-09
3.10E-W
6.39t-10
8.55E-09
4.29E-08
1.63E-06
9.42E-06
4.49E-08
3.10E-06
7.10E-C9
8.55E-07
1.491-10
5.75E-10
2.02E-11
1.3BE-09
9.41E-11
Hazard [ndei: Caoeincd Expoiure
Enceti Lifetira* Carcinogenic titk:
eti Eipofurt
9.29E-03
8.22E-06
a. Arithmeti: aean of turficia! toil tanvies (0 to 2 fe«t BIS). Not o>tect»d retjlti M«re tr.itro
ai 0.0 ana inc:uo»O in calculation of :ne mean. Swclcs for ynich attoeiated fiele blantt ««rt fcura
to be carManiriataa, vere not incluoeti in calculation of the mean. Available data ««re aggreagatee far
both the r*. and old titet.
b. Arithmetic mean of two background tanvles. See Section 2.0 for additional infonwtioo.
c. Dose calculated attuning ingestion eioosure to 0.1 g of toil per vork day, 5 days per «e«k, 4C veets ptr year
(taking into consideration inc. cover), for 30 years of a 70 year lifetime, acceptors are assomee to oe 70 15
3-3
-------
ATTACHMENT 6
Figure 7-1. Risk Assessment Summary
Noncarcinogenic Effects
(Potential for Noncar. Effects)
100.000 |
10.000 i
Chronic Exposure
OSB
OSG
G-120B NSG Trout Seep
Sites Under Investigation
Pond
OSB-Old Site bedrock aquifer
OSO-Otd Site galcial aquifer
G-120B-Bedrock aquifer. G-120 area
NSG-New Site glacial aquifer
Trout-Trout Lake
Seep-North Slope seep
Pond-Gravel Pit/Stock Pond
Noncarcinog. Effects
HH Hazard Index
(•) Hazard Index >1.0 indicates
potential for adverse
noncarcinogenic effects.
-------
ATTACHMENT 7
Figure 7-2. Risk Assessment Summary
Carcinogenic Effects
1.000E-01 i
1.000E-02|
1.000E-03 g
1.000E-04
1.000E-05
1.000E-06 i|
1.000E-07
1.000E-08
(Excess Lifetime Cancer Risk)
Chronic Exposure
OSB OSG G-120B NSG Trout Seep
Sites Under Investigation
Pond
OSB-Old Site bedrock aquifer
OSG-Old Site galcial aquifer
Q-120B-Bedrock aquifer. G-120 area
NSG-New Site glacial aquifer
Trout-Trout Lake
Seep-North Slope aeep
Pond-Gravel Pit/Stock Pond
Excess Lifetime
Cancer Risk
(•) EPA has established the
risk range of 10-7 to 10-4
as protective of human health
and appropriate for selecting
remedial alternatives.
-------
ATTACHMENT 8a
RISK ASSESSMENT SUMMARY FOR GROUND WATER
(CARCINOGENIC EFFECTS)
10
TARGET
RISK
RANGE
Current US Ecology RCRA Practical Background
Ground Water Proposed Quantttation Ground Water
Concentrations Cleanup Goal* Limit* (POL) Concentration*
04/20/90
-------
ATTACHMENT 8b
RISK ASSESSMENT SUMMARY FOR GROUND WATER
(NONCARCINOGENIC EFFECTS)
100 -r
10 --
0.1 --
0.01 J-
0.001 --
0.0001 --
RISKS
SIGNIRCANT
RISKS NOT
SIGNIRCANT
Current
Ground Water
Concentrations
US Ecology
Proposed
Cleanup Goals
RCRA Practical
Quantitation
Umrta (POL)
Background
Ground Water
Concentrations
008-OOS013
NONCAflC.GRF
04/20/80
-------
ATTACHMENT 9
DOCUMENTS CM FILE AT REPOSITORY LOCATED IN SHEFFIELD PUBLIC LIBRARY
136 East Cook St.
Sheffield, Illinois 61361
1. Copy of Administrative Order by Consent (dated 9/30/85)
2. Preliminary Screening of Remedial Technologies and Development of
Alternatives (August 19, 1988)
3. Revised Final RJ Report (2nd revision: April 17, 1989)
4. Draft Feasibility Study for Ground«ater Remediation (June 27, 1989) -
- 2 volumes
5. Draft Feasibility Study for Source Control (3/31/89) — 1 vol'jree
6. Soils ^Jer.dum to the Final RI Report (July 14, 1989) — 3 vclur.es
(one is larelec Vol. 1 and the others are Appendix A and B)
7. Appeici:: 0: Toxicity Profiles (July 14, 1989) (Appendix to Fir.al RI
Report)
8. Appendix H-4, January 1983, Analysis Data
*
9. Revised .^'jppendices for the Revised Final RI Report (Dated February
15, 1989)
10. Work Plan for the Acquisition of Soil and Sediment Chemical Data
(February 8, 1989)
11. Work Plan for Conducting Treatability Studies (March 31, 1989)
12. Treatability Study Report (June 23, 1989)
------- |