FOR THE

       May 1990

                           TABLE OF CONTENTS

   I                     Statement of Document's Purpose                     1

  II                     Site Background                                     3

 III                     Feasibility Study Surmery                           7

  IV                     Summary of Remedial Alternatives                    8

                           Ground-water Remediation                          8
                           Source Control                                   14

   V                     The Preferred Alternative                          20

  VI                     Criteria for Comparison of                         24

 VII                     Comparison of Alternatives                         26

VIII                     The Comnunity's Role in the                        37
                           Selection Process

                         Attachments (9)



                           List of Documents in Repository (partial)


    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.


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.


     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


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

    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:


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;


    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-

    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
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


      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

             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).

      During the Feasibility Study (FS), US Ecology identified and


     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.


     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


     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

    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


    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."


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


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


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


    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


       -  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)


 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


    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
       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/


    0  Subsurface extraction trenches:

       - circumferentially around Old Site trenches

       - around 18EW3 plume

       - around plume in G-120 area


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


    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
    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


   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


         Time to Inplement:  Design and contractor procurement = 1 1/2  yrs.

                             Tijne for excavation and disposal  = 2      yrs.
                                                    Total      = 3 1/2  yrs.


     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


                        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

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;


    0  U.S. EPA's ground-water protection standards were achieved;

    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:


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

    0  Implementation of modifications to the existing New Site clay
       cap, if required by IEPA.

    Estimated Cost (total for preferred alternative)


         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.


     Each alternative in the draft FS reports was evaluated against the

     following list of criteria, as required by the NCP and RI/FS


     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


    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


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.



      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


    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


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


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.


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.


    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


    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


    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


    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


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.


    Alternative 3 is tentatively preferred because:
       No biological sludge is produced requiring transport and

       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

    selected grouivi-water remedy if determined to be necessary after

    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

    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

    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,

    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

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

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


    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



        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.

        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


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


corrective measure alternative  for the US Ecology facility in Sheffield,


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.

                BUREAU COUNTY

                    ATTACHMENT 2
II ./ /I/
11 / /.
II / L?

                               ATTACHMENT 3
m i U.IA—ay

                                        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
 Hazard Index
Excess Lifetime
 Cancer Risk:
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



                                      ATTACHMENT  5
                          TABLE 3-1. IISl CM»»ACTEBir»T;o«:  IHCESTIOn EXPOSURE TO SU»»»CE SOUS
Beryl 1 ium
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'*)




1. Jit -08

S. 971-04
4.rt>E-03 8.22E-06
J. 771-04
4.Jtf -05

Carbon Tetracniorioi*
Hethylene Chloride
1,1, 1-Tricfi(oro«tnane


Hazard [ndei:  Caoeincd Expoiure

Enceti Lifetira* Carcinogenic  titk:
      eti Eipofurt
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

                                    ATTACHMENT 6
               Figure 7-1.  Risk Assessment  Summary
                          Noncarcinogenic  Effects
            (Potential for Noncar. Effects)
    100.000 |

     10.000 i
                                    Chronic Exposure
G-120B    NSG    Trout    Seep
Sites Under Investigation
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-03 g



   1.000E-06 i|


              (Excess Lifetime Cancer Risk)
                       Chronic Exposure
                OSB    OSG   G-120B   NSG    Trout    Seep
                               Sites Under Investigation
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

                 (CARCINOGENIC EFFECTS)
        Current        US Ecology      RCRA Practical    Background
        Ground Water    Proposed       Quantttation     Ground Water
        Concentrations   Cleanup Goal*    Limit* (POL)     Concentration*

                               ATTACHMENT 8b
                   (NONCARCINOGENIC EFFECTS)
  100 -r
   10 --
   0.1 --
  0.01 J-
 0.001 --
0.0001 --
                                                                  RISKS NOT
            Ground Water
US Ecology
Cleanup Goals
RCRA Practical
Umrta (POL)
Ground Water

                             ATTACHMENT 9
                            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

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)