UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
RESPONSE TO COMMENTS
FOR THE
US ECOLOGY, INC. SITE
SHEFFIELD, ILLINOIS
OCTOBER 1990
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US ECOLOGY, INC.
SHEFFIELD, ILLINOIS
(ILD 045 063 450)
INTRODUCTION
This response to comments (RTC) is being presented by the United States
Environmental Protection Agency (U.S. EPA). The purpose of the RTC is to
present concerns and issues raised during the public comment period and to
provide responses. All of the significant comments received were carefully
reviewed during the final selection of the remedy and have been responded to
in this RTC. Some additional alternatives and suggested additions to
components of the remedy were raised by commenters that were not considered
during the Corrective Measure Study (CMS), previously referred to as the
Feasibility Study (FS). All these comments have been considered, and the
selected remedy is the proposed remedy with some modifications and
clarification. To the extent possible, and where appropriate, additional
details and requirements have been added to direct US Ecology, Inc. in the
Corrective Measure Implementation (CMI) design phase, which will be initiated
following the signing and release of this document.
The U.S. EPA, in its selection of the corrective measures to be
implemented by US Ecology at its Sheffield, Illinois, landfills, has
determined that the individual components of the remedy for source control and
ground-water remediation will be both effective and protective. The selected
remedy was chosen by U.S. EPA to promote remediation of contamination from
both past and continuing releases of hazardous waste and/or hazardous
constituents to ground water and to significantly reduce the likelihood of
future releases from those areas addressed. However, the U.S. EPA wishes to
make the following points very clear:
1. The Administrative Order By Consent, signed by U.S. EPA and US
Ecology, remains in effect after remedy selection. Under Section
VIII, titled Additional Work, U.S. EPA can require US Ecology to
conduct additional remediation investigation (RI) work and/or
feasibility studies (FS) if the Agency makes a determination that
it is necessary.
2. Although U.S. EPA expects the number of future releases to be
reduced once source control components are designed, approved, and
implemented, it is clear that U.S. EPA retains statutory authority
for corrective action, which can be used to address any newly-
identified areas of releases (e.g., from different areas of the
New Site (see Figure 1)).
3. If it is determined, following implementation of the selected
corrective measures, that a specific component is not achieving
the design specifications and, as such, will not be effective in
source control or remediation of ground water, U.S. EPA will
require US Ecology to redesign and reimplement the specific remedy
component or implement another technology following further FS
work.
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n>
U S ECOLOGY SHEFFIELD HAZARDOUS WASTE DISPOSAL SITES
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US Ecology Is obligated under Section X of the Consent Order, titled
Corrective Action, to implement the corrective action selected by U.S. EPA.
The corrective action will be completed in accordance with Attachment I to
this document (i.e., Scope of Work for Corrective Measures Implementation at
US Ecology, Inc., Sheffield, Illinois). The Consent Order (Section XVII.C)
provides for financial assurance in the amount of $1,750,000.00 to guarantee
performance of and payment for any corrective action selected by U.S. EPA.
SELECTED CORRECTIVE MEASURES
The selected corrective measures consists of two essential elements:
(1) source control, and (2) ground-water remediation. These two elements are
detailed below and depicted in Figure 2.
1. The selected corrective measures for source control consist of the
following components, some of which are described in considerable detail
in the draft FS report for source control (Alternative 1):
a. Placing slurry walls around the Old Site trenches.
b. Placing slurry walls at trench I8EWC and the G-120 area of the New
Site.
c. Capping of the Old Site with a RCRA-required cap.
d. Implementation of modifications to the existing New Site clay cap,
if required by the Illinois Environmental Protection Agency (IEPA)
for closure purposes.
e. Extension of RCRA-required caps over areas encircled by slurry
walls tied into existing barrier walls at 18EWC and the G-120
area.
f. 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.
g. Because of concerns expressed by commenters regarding the adequacy
of the existing system of ground-water monitoring wells to detect
releases, US Ecology will be required to reduce the spacing
between existing wells by approximately one-half north of New Site
trenches 4, 5, and 24; west of trenches 24, 23, and 22; south of
trench 23; and east of trenches 14C, 15, 16B, and 18EWB.
h. Installation of sumps and/or extraction wells inside the slurry-
walled and capped areas at trench 18EWC and G-120.
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GROUND WATER
SEEPS
18EWC AREA
LEGEND
SLURRY WALL
CAP/COVER
GROUND WATER CONTAMINATION
(OLD SITE PLUME)
GROUND WATER EXTRACTION WELLS
U S ECOLOGY SHEFFIELD SITE
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i. Repair or modification of the existing trench barrier walls at
18EWC to ensure that they are effectively tied into a low-
permeability stratum beneath the trench.
j. Installation of additional effective sumps into New Site trenches
1, 2, and 3, and 18EWC to control leachate generation and release
from these trenches.
2. U.S. EPA's selected corrective measures for ground-water remediation
will require US Ecology to:
a. Employ 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: 10.0
Benzene: 5.0 /jg/L
Chloroform: 5.0 /jg/L
1,1-Dichloroethane: 5.0 /jg/L
1,2-Dichloroethane: 5.0 /ig/L
1,1-Dichloroethylene: 5.0 /ig/L
1,2-Dichloropropane: 5.0 fig/L
Methyl ene Chloride: 5.0 jjg/L
Tetrachloroethylene: 5.0 /ig/L
Trichloroethylene: 5.0 /*g/L
Vinyl Chloride: 2.0 /tg/L
b. Treat the removed ground water as necessary to comply with
applicable State regulatory programs for discharge to air, surface
water, and ground water (e.g., reinjection).
c. Provide a ground-water monitoring program to verify progress
toward achieving U.S. EPA's ground-water protection standards.
d. Screen ground-water extraction wells in both the glacial aquifer
and bedrock aquifer (including the G-120 area), as necessary, to
achieve the ground-water protection standards specified herein in
both the saturated zones.
e. Perform additional ground-water modeling to predict, to the extent
possible, the effects of implementing the selected corrective
measures particularly in regard to the low level radioactive waste
(LLRW) site.
f. Provide for the placement of piezometers, and the institution of
regular recordkeeping of water-level measurements in them, to
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allow detection, assessment, and to assist in management of any
potentially adverse effects on the ground-water gradients
associated with the adjacent LLRW site.
g. Develop and submit contingency plans to raise or lower the ground-
water levels associated with the LLRW site in the event that the
implemented corrective measures (source control and/or ground-
water remediation activities) are determined to be producing
adverse effects on the LLRW site ground-water flow direction,
ground-water elevations, etc.
h. Develop a treatment system(s) capable of handling extracted ground
water removed from the chemical plume, including those areas where
the radiochemical plume is mixed with the chemical plume. This
requirement will include regular sampling of extracted ground
water for those radionuclide parameters in Table 5-7 of the Final
Remedial Investigation (RI) report plus 1-129 and appropriate
handling, treatment, storage, or disposal of the water and sludge.
The detailed designs for implementing these corrective measures will be
developed in accordance with the Scope of Work for CMI attached to this
document. In addition to these requirements, the following activities will be
initiated/continued and considered.
1. Site access restrictions (including Trout Lake);
2. Collection of water discharging from the New Site north slope seeps and
its treatment and discharge; and
3. Installation of additional monitoring wells in the Herrin Coal, upon
approval of the plan by U.S. EPA.
The selected corrective measures provide the best balance among the
alternatives with respect to the evaluation criteria, including:
• Long-term reliability and effectiveness;
• Reduction of toxicity, mobility, or volume of waste;
• Short-term effectiveness;
• Implementability; and
• Cost.
The selected corrective measures provide overall protection of human health
and the environment as follows:
1. Source Control
The selected corrective measures for source control are 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 18EWC 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
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wastes and contaminated soils and reduce further contaminant migration
to ground water. RCRA-requlred caps, designed to achieve the maximum
effective lifetime with the lowest maintenance, over the Old and New
Sites and cap extensions over the G-120 and 18EWC plume areas will
reduce the chance of exposure to contaminated soil and significantly
reduce surface water Infiltration, leachate generation and mobility, 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 inside the walls that 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 treatment system. 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 the
selected source control, 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.
Slurry wall technology is commonly used. However, its use requires care
in design and implementation to achieve the desired goals of containment
and isolation of the hazardous wastes. Installation of landfill capping
and its maintenance is straightforward. The estimated costs of
implementing the slurry wall and Old Site cap are $1,153,500 and
$928,000, respectively, over thirty (30) years. The slurry walls could
be designed and installed in two (2) years.
2. Ground Water
The selected corrective measures for ground-water remediation will
provide adequate protection of human health and the environment since
they provide for halting plume expansion and initiating remediation of
the plumes of contamination by extraction and treatment of ground water
(i.e., from the Old Site, trench 18EWC, the G-120 area, and the north
slope seeps). Following ground-water remediation by using reliable
metals precipitation, air stripping, and carbon adsorption technologies
to achieve the concentrations proposed by U.S. EPA, the residual health
risks from ingestion of ground water will be reduced to acceptable
levels. The draft FS report estimates there will be a 98 percent
reduction of the total mass of organic constituents in the ground water
within thirty (30) years. Extraction and ground-water treatment will
continue indefinitely toward achieving U.S. EPA's ground-water
protection standards. A National Pollutant Discharge Elimination System
(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
concentration 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 treatment of the ground water will reduce
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or eliminate potential risks from ingestion of contaminated ground water
downgradient of the landfill at any off-site location.
It is estimated that it will take eighteen (18) months to design and
install the ground-water treatment system. All components are readily
available technologies that have been extensively used at other sites
and do not restrict future expansion or modification of the selected
ground-water corrective measures. The estimated cost over thirty (30)
years for the ground-water remediation is projected to be about $10
million.
The total cost of the selected corrective measures is estimated to be
about $12 million over thirty (30) years.
COMMUNITY RELATIONS ACTIVITIES
U.S. EPA released the Proposed Plan for the US Ecology, Sheffield,
Illinois, facility in May 1990. At citizens' requests, a 2-week informational
period was scheduled by U.S. EPA from May 14 to May 28, 1990. This period
permitted the public to become familiar with the Proposed Plan prior to the
start of a 45-day comment period. The comment period began on May 28 and
terminated on July 26, 1990, fifteen (15) days after the original closure
date. The extension to the comment period was granted at the request of
Attorney General Neil Hartigan and Congressman Lane Evans.
On June 14, 1990, U.S. EPA conducted an informational meeting at the
Buda-Sheffield Western School in Buda, Illinois. The purpose of the meeting
was to present and explain the Proposed Plan and to answer the community's
questions on a more informal basis. Over seventy-five (75) people attended
the slide presentation and question and answer period that followed. A court
reporter recorded the meeting and a transcript was made and is available at
the Information Repository at the public library in Sheffield, Illinois.
U.S. EPA held a public hearing on June 28, 1990, to take and record
formal comments on the Proposed Plan. Transcripts from the court reporter
have been made available. Approximately 150 people attended the hearing and
fifteen (15) people gave oral testimony. The meeting was attended by
representatives from the Illinois Environmental Protection Agency (IEPA), the
Illinois Department of Nuclear Safety (IDNS), the Attorney General's office,
Senator Simon's office, Representative Mautino's office, and the press.
U.S. EPA regularly updates the community through letters, to citizens,
media relations, and conversations with citizens.
CONCERNS RAISED DURING THE COMMENT PERIOD
During the public comment period, U.S. EPA received written comments on
the proposed plan from several sources including government officials and
agencies, citizen groups and their representatives, private citizens, and US
Ecology. Additional comments are included within the transcripts of the June
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14 public informational meeting and June 28 public hearing. Table 1 lists all
written comments received by the Agency. A complete copy of all written
comments is available for review at the U.S. EPA, Region 5, library (located
on the 16th Floor, 230 South Dearborn Street, Chicago, Illinois), and at the
Information Repository in the public library in Sheffield, Illinois.
All comments presented in this section are referenced according to
source document numbers presented in Table 1. For example, comments from
William C. Child of the Illinois Environmental Protection Agency (IEPA) are
referenced as A2, while comments from Eloise Baker, a private citizen, are
referenced as C7. Citations are also provided for the location of the
comments [page (p), paragraph (U), and section (§)] within a source document,
as appropriate. For example, a specific comment that appeared on page 3,
Section 6 of William C. Child's (IEPA) written comments would be referenced as
[A2,p.3,§6]; a specific comment from the first paragraph on page 2 of Eloise
Baker's written comments would be referenced as [C7,p.2,<|[l]. In cases where
U.S. EPA received the same comment from several sources, all sources are
referenced. For example, a comment that was made by both William C. Child of
IEPA and Eloise Baker might be referenced as [A2,p.2,§2; C7,p.l,1f3].
The comments listed below are separated into seven categories. The
categories are titled:
I. Source Control Corrective Measures
II. Ground-Water Corrective Measures
III. Site Geology and Hydrogeology
IV. Remedial Investigation and Feasibility Study
V. Interactions Between Chemical and Radioactive Waste
VI. Health Effects and Cleanup Goals
VII. Miscellaneous Comments
I. SOURCE CONTROL CORRECTIVE MEASURES
1. Concern:
IEPA and others questioned the technical feasibility of slurry
wall installation and is concerned that installing the slurry wall
through permeable, saturated and unconsolidated sediments will
cause the sediments to collapse into the trench. [A2,p.l,§la;
B6,p.II-l,§2; E2,p.55,H2]
Response:
Experienced engineers and contractors are available for hire by US
Ecology who can overcome, by increased engineering, the potential
limitations raised by IEPA regarding slurry wall installation.
Regarding the issue of depth, walls up to eighty (80) feet can be
installed with modified backhoes; deeper walls would most likely
utilize a hydraulic clam shell. The potential for collapse of
unconsolidated sediments into the trench during excavation will be
eliminated by introduction of slurry just after the trench is
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TABLE 1
LIST OF PUBLIC COMMENTS
ON U.S. ERA'S PROPOSED PLAN
FOR US ECOLOGY'S SHEFFIELD
HAZARDOUS WASTE SITES
A. Government Agencies and Public Officials
1. Lane Evans, Congressman, "Remarks of Congressman Lane Evans, US Ecology
Chemical Waste Disposal Facility, Hearing on the Corrective Action
Plan," written statement read at June 28, 1990, Public Hearing by
Jerry Lack (received June 28, 1990)
2. William C. Child, Manager, Division of Land Pollution Control, Illinois
Environmental Protection Agency, letter to David A. Ullrich, U.S.
Environmental Protection Agency, undated (received June 28, 1990)
3. Dave Ed, Senior Scientist, Illinois Department of Nuclear Safety,
"Statement by the Illinois Department of Nuclear Safety at the
U.S. Environmental Protection Agency's Public Hearing on the
Proposed Plan for Corrective Action at the US Ecology Inc.
Hazardous Waste Facility Near Sheffield, Illinois," written
statement read at June 28, 1990, Public Hearing (received June 28,
1990)
4. Thomas W. Ortciger, Director, State of Illinois Department of Nuclear
Safety, letter to Jonathan Cooper, U.S. Environmental Protection
Agency, July 10, 1990 (received July 11, 1990)
5. Neil F. Hartigan, Attorney General, State of Illinois, letter (with
attached "Comments of the People of the State of Illinois and the
County of Bureau Concerning the United States Environmental
Protection Agency's Proposed Plan for the US Ecology, Site,
Sheffield, Bureau County, Illinois") to Valdas V. Adamkas,
Regional Administrator, U.S. Environmental Protection Agency
(dated and received July 26, 1990)
B. Citizens' Groups
1. Rodger Bruyn, Manager, Bureau County Farm Bureau, memo (with attached
report "A Review of the Final Remedial Investigation Report for
the Sheffield Hazardous Waste Disposal Sites" prepared by K.W.
Brown & Associates, Inc., College Station, Texas, July 1989) to
Thomas J. Kenney, U.S. Environmental Protection Agency, August 15,
1989
8
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TABLE 1 (Continued)
LIST OF PUBLIC COMMENTS
ON U.S. ERA'S PROPOSED PLAN
FOR US ECOLOGY'S SHEFFIELD
HAZARDOUS WASTE SITES
2. Dr. R.S. Nelson, Environmental Exploration Associates, Inc.
(representing Associated Citizens for Protection of the
Environment), "Summary -- Evaluation of Geology and the Hazardous
Waste Sites, Sheffield, 111.," written comments submitted at June
28, 1990, Public Hearing (received June 28, 1990)
3. Stan Gingrich, President, Associated Citizens for Protection of the
Environment, written statement read at June 28, 1990, Public
Hearing (received June 28, 1990)
4. Alan T. Dale, President, Bureau County Farm Bureau, "Public Hearing —
U.S. EPA Remediation Proposal," written statement read at June 28,
1990, Public Hearing (received July 12, 1990)
5. Rodger Bruyn, Manager, Bureau County Farm Bureau, "Farm Bureau's
Position," written statement read at June 28, 1990, Public Hearing
(received June 28, 1990)
6. Jeanine L. Morse, Hydrogeologic Consultant for Bureau County Farm
Bureau, "Comments on the Final Remedial Investigation, Draft
Feasibility Study Reports and the Proposed Plan for Corrective
Action for the US Ecology, Inc. Landfill Near Sheffield, Bureau
County, Illinois," written comments submitted at June 28, 1990,
Public Hearing (received June 28, 1990)
7. Dr. R.S. Nelson, Environmental Exploration Associates, Inc. (On Behalf
of Associated Citizens for Protection of the Environment),
"Geologic and Hydrologic Interpretation & Comments on Proposed
Corrective Action, US Ecology Hazardous Waste Sites, Sheffield,
Illinois," dated July 11, 1990 (received July 26, 1990)
C. Private Citizens
1. Chester M. Grafft, Princeton, Illinois, written comments submitted at
June 28, 1990, Public Hearing (received June 28, 1990)
2. Steve Barlow, Princeton, Illinois, written statement read at June 28,
1990, Public Hearing (received June 28, 1990)
3. Roy L. Mahnesmith and Edward F. Glubczynski, memo to Jonathan Cooper,
U.S. Environmental Protection Agency, July 6, 1990 (received July
10, 1990)
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TABLE 1 (Continued)
LIST OF PUBLIC COMMENTS
ON U.S. ERA'S PROPOSED PLAN
FOR US ECOLOGY'S SHEFFIELD
HAZARDOUS WASTE SITES
4. Laverne Weidler, Kewanee, Illinois, letter to Jonathan Cooper, U.S.
Environmental Protection Agency, undated (received July 12, 1990)
5. Timothy D. Wilson, Sheffield, Illinois, written comments (postmarked
July 10, 1990)
6. Mr. and Mrs. Ronald Wilson, Sheffield, Illinois, written comments
(postmarked July 10, 1990)
7. Eloise P. Baker, Neponset, Illinois, written comments (postmarked July
18, 1990)
8. Eloise P. Baker, Neponset, Illinois, written comments (postmarked July
24, 1990)
9. I. Jay and Louise J. Langford, Sheffield, Illinois, written comments
dated July 19, 1990 (received July 25, 1990)
10. Ted Strouse, Buda Illinois, written comments dated July 18, 1990
(received July 20, 1990)
11. Rev. Frank Rottier, Sheffield, Illinois, written comments dated July 16,
1990 (received July 26, 1990)
D. US Ecology
1. Laurence Levine, US Ecology, Inc., written comments (received June 28,
1990).
2. Bradley E. Dillon, General Counsel, US Ecology, Inc., "US Ecology,
Inc.'s Comments on U.S. EPA's Proposed Plan (with Attachments 1
through 13)," dated July 26, 1990 (received July 27, 1990)
E. Transcripts from Public Meeting and Public Hearing
1. Transcript of "The Informational Meeting on U.S. EPA's Proposed Plan for
Corrective Measures for the US Ecology, Inc. Site, Sheffield,
Illinois," held at Buda-Sheffield Western School, Buda, Illinois,
June 14, 1990 (prepared by Kathy L. Johnson Professional Reporting
Services)
10
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TABLE 1 (Continued)
LIST OF PUBLIC COMMENTS
ON U.S. ERA'S PROPOSED PLAN
FOR US ECOLOGY'S SHEFFIELD
HAZARDOUS WASTE SITES
2. Transcript of "The Public Meeting on U.S. EPA's Proposed Plan for
Corrective Measures for the US Ecology, Inc. Site, Sheffield,
Illinois," held at Bureau County Courthouse, Princeton, Illinois,
June 28, 1990 (prepared by Kathy L. Johnson Professional Reporting
Services)
11
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opened and before the water table Is reached. The
viscosity/density of the slurry is maintained at a level that is
appropriate for hydraulically shoring up and stabilizing the
trench walls. Also, during trench excavation, a thin filter cake
forms on the trench walls minimizing slurry loss into the
surrounding geologic materials, stabilizing the soil in contact
with the slurry, and providing a plane on each trench wall against
which the hydraulic pressure of the slurry can act to stabilize
the excavation (EPA/540-2-84-001; Feb. 1984). Test borings will
be done along the proposed wall locations during the design phases
of Corrective Measure Implementation (CMI) and the presence of the
various sediment types will be considered in fine tuning the
engineering design.
2. Concern:
Compatibility tests of the waste with bentonite slurry walls were
not performed. Bentonite is sensitive to chemical attack and
alteration and published information (EPA/530-SW-86-007; March
1986) does not recommend soil/bentonite mixtures for use where
hazardous waste or leachates occur. [A2,p.l,§lb; A5,p.2,H2]
Response:
The potential for adverse effects on slurry wall materials from
chemicals exists and will be addressed. Compatibility tests will
be performed during the CMI design phase. A work plan will be
required which will describe procedures to collect representative
leachate (ground water) samples from the site. These will be used
in specified laboratory tests to determine the effects of the
leachate on various proposed backfill mixtures which incorporate
site soils and other soils with different types of bentonites.
The specific draft document cited in this concern is titled:
Design, construction, and evaluation of clav liners for waste
iranagemcint facilities. The vertical slurry walls:
a. Will not be in direct contact with hazardous waste as a
landfill liner might be, but instead with contaminated
ground water (i.e., less concentrated);
b. Will be used in conjunction with complementary technologies
(i.e., an effective landfill cap and ground-water extraction
wells inside the slurry-walled areas). The extraction wells
in the Old Site constitute use of slurry walls with active
(rather than passive) management, "mat is, the hydraulic
gradient will be inward into the Old Site thereby
controlling releases of leachate moving outward through the
wall. It is expected then that any water which permeates
the slurry wall around the Old Site, when the extraction
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13
wells are operable, will be less contaminated and have less
of a potential for an adverse impact on the slurry wall.
c. Will be In contact with more dilute organic solutions than
those used In some laboratory studies showing marked
permeability Increases In clays. Tests conducted with less
concentrated solutions of organics (I.e., at or near their
solubility limits In aqueous solution) caused no appreciable
Increases In permeability (Evans, Fang, and Kugelman, 1985).
d. Will be engineered and designed to the fullest degree
possible In relation to this important concern. Different
types of bentonite and even other types of clay, less
affected by chemical attack, can be used.
3. Concern:
Commenters are concerned that ground water will mound on the
outside of the slurry wall and cause an increased gradient through
the wall which may result in containment failure. [A2,p.2,§2a]
Response:
A potential does exist for mounding of ground water beneath the
New Site immediately west of the proposed location of the west
side of the Old Site slurry wall. Because of the increased
potential for piping and hydrofracturing in a wall if the head
differential across a slurry wall is high, U.S. EPA will require
the design phase to ensure eventual: (1) implementation of a wall
as homogeneous, both horizontally and vertically, as possible; (2)
use of only specified backfill materials to yield the established
design permeability; (3) requirement of monitoring of ground-water
levels inside and outside of the wall to ensure that design head
levels are not exceeded; and (4) ability to control the hydraulic
gradient across the wall by appropriate use of extraction wells on
both sides of the wall.
4. Concern:
US Ecology did not evaluate the cap on the New Site to determine
if it meets the minimum technology requirements for landfill cover
pursuant to 35 Illinois Administrative Code 724.410a. [A2,p.2,§5]
Response:
US Ecology has already responded to this comment by IEPA.
Attachment 4 of their submittal evaluates the existing New Site
cap and IEPA has a copy of this. US Ecology referred to landfill
final cover design objectives as "10 CFR 264.310a". That should
read 40 CFR 264.310a. The State analogs are 35 111. Adm. Code
724.410a. US Ecology will be required to implement a RCRA-
approved cap.
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5. Concern:
Commenters question the plan to 'key' the slurry wall three feet
into the bedrock because the bedrock is comprised of various
geologic units of differing permeability. US Ecology has not
evaluated the effectiveness of keying a slurry wall into fractured
bedrock. Therefore, the ability of the wall to cut-off the
ground-water flow can not be judged. [AS,p.3,12; A2,p.l,§lc]
Response:
These comments raise potentially valid concerns, but increased
engineering and design can surmount these problems if these
conditions actually exist beneath the Old Site at the depth at
which the slurry walls would be keyed into bedrock. The RI report
examined the bedrock for the presence of fractures and jointing.
These are stated in the RI report to be "sparse based on
observations from core samples, caliper logs, and borehole
televiewer logs" (pages 4-67, 4-69). During the actual design
phase, an approved plan will require drilling boreholes on a
specified spacing along the actual slurry wall location to further
characterize the sediments through which the trenching and
installation will occur. In addition, cores of bedrock will be
taken to the design depths for examination.
U.S. EPA believes the following factors indicate that this comment
is less of a concern than it initially might appear: (1) this
further subsurface study will provide additional location-specific
information during the design phase to ensure an adequate keying
of the wall into bedrock; (2) the ground-water level within the
slurry wall will be maintained at or near the surface of the
bedrock as extraction wells remove ground water inside the slurry
wall thus eliminating all or most of the vertical driving force;
and (3) data from monitoring wells during the RI study have shown
that the bedrock is relatively uncontaminated and that most of the
organic contamination is migrating along the interface between the
bedrock and glacial sediments (i.e., the tendency on site appears
to be for lateral, not vertical, movement of ground water).
6. Concern:
Commenter states that a major flaw in the plan is that it does not
address excavation of the Old Site as an alternative and suggests
U.S. EPA reconsider alternatives such as solidification or
incineration and aboveground storage. [Al,p.l,15; B2,p.2,14;
B3,p.2,12; C2,p.2; C3,p.l,§6; C7,p.2,ll; C9,p.l,ll; C11.15;
Bl,App.A,p.l,12 and p.2,HI; Bl,App.A,p.3,ll; B5,p.2,15;
E2,p.18,14; E2,p.35,15; E2,p.43,11; E2,p.56,14; E2,p.62,12;
E2,p.80,ll]
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15
Response:
Excavation of the hazardous wastes at the Sheffield site has been
fully evaluated. US Ecology initially eliminated exhumation in
the document titled "Preliminary Screening of Remedial
Technologies and Development of Alternatives" (dated August 19,
1988). U.S. EPA required, however, that exhumation be evaluated
further in the FS documents and this was done. For reasons stated
in the Proposed Plan (e.g., short-term hazards to workers and
nearby residences from potential explosions or releases of
volatiles to the air; a longer implementation time; the need for
special equipment and permits; and disposal capacity issues),
exhumation was not selected by U.S. EPA as a component of the
preferred alternative. As such, solidification and incineration,
processes performed following the exhumation of the hazardous
wastes, are also eliminated from further consideration.
Aboveground storage of land disposal restricted wastes in waste
piles is banned and storage in tanks and containers is not
permitted under the regulations (40 CFR 268.50(a)) for more than
one year absent appropriate treatment (40 CFR 265.41 to 268.43).
7. Concern:
The reliability and effectiveness of proposed slurry walls and
landfill caps as components of a containment system were
questioned. [Al,p.l,^7; C5; C6; C7,p.l,^3; Bl,App.A,p.l,^[l and
p.2,12; E2,p.18,15]
Response:
Landfill caps are a commonly used technology for reducing surface
water infiltration into burial trenches containing hazardous
wastes. U.S. EPA issued a technical guidance document for
caps/covers titled "Final Covers on Hazardous Wastes Landfills and
Surface Impoundments" (EPA/530-SW-89-047; July 1989). During cap
design, many factors will be considered including, but not limited
to: existing trench bottom liner permeability; slope of the final
cap (to promote runoff, but to minimize erosion); inclusion of
drainage layers in the design; a top vegetative or armored surface
component; and freeze-thaw phenomena. In addition to designing
effective and appropriate covers for the landfills, the design
will also rely on sumps and/or extraction wells to permit
collection and removal of any surface water that does infiltrate
the cover.
Regarding the reliability and effectiveness of slurry walls,
please refer to the responses to concerns 1.2 and 1.5.
8. Concern:
Several commenters questioned the effectiveness of slurry walls
proposed for the New Site. One commenter suggested that the
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16
slurry walls will not be tied into lateral barriers and will be
aligned parallel to ground-water flow. Thus, they will have
little effect on contaminant migration. Another commenter
suggests that the existing barrier wall around the New Site is not
keyed into the bedrock. Since slurry walls will be constructed
along only a small portion of the barrier wall, they will not be
effective in stopping ground-water flow along most of the wall.
[A5,p.6,Hl; B2,p.2,13; B7,p.l,H3; B7,p.l5,f2; B6,p.II-3,§10]
Response:
Existing New Site barrier walls were not required or designed to
be keyed into bedrock under the construction permit. The barriers
to vertical flow in the New Site consist of in situ scraped and
reworked glacial materials in the east portion of the site and, in
the western portion, a ten- (10) foot thick low-permeability,
imported material recompacted under the trenches. Lateral
barriers were also constructed of recompacted, low-permeability
materials. Slurry walls, installed in a semi-circular
configuration, are proposed which will both tie into existing
lateral barrier walls and key into bedrock in two locations around
the New Site where ground-water contamination has indicated
releases from the facility (i.e., G-120 and 18EWC areas). These
slurry walls are expected to be effective by practically
encircling the areas of releases by slurry walls and lateral
barrier walls, covering the encircled areas with an effective
landfill cover, installing extraction wells positioned inside the
slurry walls such that they capture any existing or continuing
releases of contaminated ground water, and reducing the likelihood
of further releases from landfill trenches by installing
additional sumps (or more aggressively pumping existing sumps) and
installation of a more effective cap over the New Site.
9. Concern:
Eloise Baker, speaking on the behalf of the Associated Citizens
for Protection of the Environment (ACRE), stressed the importance
of extracting the water in the New Site trenches and preventing
ground water from entering waste disposal cells by installing
protective caps. [C7,p.l,H6]
Response:
U.S. EPA concurs with the comment. Removal of any water in
trenches reduces the head or vertical driving force.
10. Concern:
One commenter agreed with U.S. EPA's proposed corrective action
plan for the New Site. [C2,p.2,!l]
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17
Response:
U.S. EPA appreciates the input of all parties.
11. Concern:
The remedy should be total encapsulation of the Old Site, New
Site, and LLRW site. The vertical containment barrier should be
constructed of concrete and extended downward five (5) feet into
the top of the Canton Shale, the uppermost bedrock unit with
hydraulic integrity. This remedy should include a perimeter drain
along the inside of the containment wall and a cap covering all
waste disposal areas and extending beyond the containment wall.
The estimated cost of this remedy, not including the cap, is $225
million. [B2,p.3,Ul; B7,p.l,H4; B7,p.16,^1; C7,p.l,f8; E2,p.32]
Response:
Dr. Robert Nelson's proposal for total encapsulation of all three
waste disposal sites would involve two different owners (i.e., the
Old and New Sites are owned by US Ecology and the LLRW site is
owned by the State of Illinois), ignores the existence of separate
jurisdictional authorities/agencies (i.e., U.S. EPA and IDNS), is
not developed or designed to the degree necessary to evaluate
either its feasibility as an alternative or its costs as required
in the FS guidance, and is not necessary based on data in the
RI/FS reports.
"Guidance for Conducting Remedial Investigations and Feasibility
Studies Under CERCLA" (EPA/540/G-89/004; October 1988) specifies
that each alternative for proposed remedies be evaluated against
factors such as effectiveness, implementability, and cost. Dr.
Nelson states that estimating the cost of total encapsulation "is
difficult because of the need to dig trenches to a depth of 120 to
150 feet through unstable surficial material into bedrock" (B7,p.
16). The cost estimate ("on the order of $225 million") does not
detail cost of individual components (e.g., equipment, materials,
labor, operation and maintenance, associated ground-water
extraction costs to allow containment implementation, etc.). It
is not even clear if this estimate includes the cost of a cap over
the three sites. It appears that the cap cost is not calculated
or considered.
Based on the results of the RI report, ongoing indicator parameter
evaluation and assessment monitoring of ground water at the New
Site, and on the geologic maps, cross sections and statements in
Dr. Nelson's report, dated July 11, 1990, U.S. EPA's selected
remedy will work. This is true for the following reasons. The
bedrock wells, if Dr. Nelson's models 1 and 2 were appropriate
theoretical models of contaminant migration, would be extensively
contaminated. However, ground water sampled from the six bedrock
wells screened in the Herrin Coal (i.e., the deepest penetration
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18
of the coal exploration borings) yielded only low levels (<, 36
parts per billion (ppb) of laboratory contaminants (e.g.,
methylene chloride, acetone, bis(2-ethylhexyl) phthalate). Even
if some contamination were migrating preferentially in a vertical
direction (a conclusion not supported by most of the RI data), Dr.
Nelson's cross sections, geologic map of the bedrock, and text
would support contamination migrating vertically to the Herrin
Coal (the base of coal borings) and then moving preferentially
horizontally at that depth. Dr. Nelson states, on page two, that
the "Herrin Coal is highly jointed with vertical and horizontal
joint spacing measured in inches or fractions of an inch" and, on
page four, that the "coals are aquifers because ground water moves
relatively easily along the abundant joints in the coal beds.
Springs and seeps typically occur where coal units outcrop."
Thus, any contamination migrating through unplugged boreholes
would eventually move laterally away from the landfills and be
captured within the cones of influence of extraction wells
required for the selected corrective measures. Because the Old
and New Site landfills are isolated on their own bedrock high
(i.e., away from the LLRW site) and because U.S. EPA's selected
remedy does not require a vertical barrier wall encircling the
LLRW site and the Old and New Sites, it will be possible to
install effective slurry walls without tying them into the Canton
Shale. If additional boreholes, to be taken along the final
location of the slurry walls during the CMI design phases,
indicate the need to tie into deeper shale (i.e., below the
Danville coal), that would then be required by U.S. EPA. Refer
also to the response to concern III.3.
12. Concern:
Slurry walls keyed into the top of bedrock will not stop the
potential leakage of contaminants from the Old Site. Contaminants
will migrate downward through unplugged boreholes, along the
bedrock aquifers, and into glacial aquifers where bedrock aquifers
subcrop beneath the Old Site. [B2,p.2,H3; B7,p.l,^3; B7,pp.14-15;
E2,p.30,12]
•
Response:
Please refer to the response directly above concerning capture of
potentially migrating contaminated ground water.
13. Concern:
The cap proposed for the Old Site should include a geomembrane and
should be thick enough to prevent infiltration of water through
cracks caused by desiccation. [C4,p.5,Hl]
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19
Response:
Issues such as the one Involving desiccation will be carefully
evaluated during review of cap designs submitted to U.S. EPA and
IEPA for approval. Technical guidance documents and experience
available from other sites will assist in selecting an effective
cap design. Flexible membrane liners (FML) may not be required
for these landfills because neither one has an FML in the bottom
and 40 CFR §265.310(a) requires that the final cover "have a
permeability less than or equal to the permeability of any bottom
liner system or natural subsoils present."
14. Concern:
US Ecology believes that releases from the 18EWC area of the New
Site have already been effectively controlled by prior activities.
With the addition of the proposed slurry walls, modifications to
the existing trench barrier wall are not necessary. [02,p.15,HI;
D2(Att.l),p.l4,14]
Response:
Although US Ecology has shown some evidence indicating possible
shrinkage in the 18EWC plume size, U.S. EPA is not convinced that
this issue is adequately resolved. The selected remedy will
require further review during the design phase of CMI to evaluate
the existing trench barrier wall's effectiveness in containing
leachate in the trench thereby allowing removal by sumps in the
trench. If the barrier wall is ineffective as constructed, repair
will be required to tie the wall into a low-permeability stratum.
15. Concern:
US Ecology believes that Resource Conservation and Recovery Act
(RCRA) land disposal restrictions will not apply to soil removed
during construction of slurry walls, as long as the removed soil
is mixed with bentonite and backfilled as part of the wall.
[02,p.16,15]
Response:
Soil excavated during construction of slurry walls will trigger
land disposal restrictions. The appropriate handling and disposal
of the contaminated soil and debris will be established during the
design phase of the CMI. The soils and debris generated may
qualify for a treatability variance under 40 CFR 268.44(h).
Please refer also to a March 8, 1990, Federal Register (55 FR
8666), which discusses these issues in relation to RCRA corrective
action. In the past, US Ecology was required to handle all
borehole cuttings as hazardous waste. This request is consistent
with past practices.
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20
16. Concern:
Since the submittal of the draft FS for source control, potential
advantages of a new barrier wall technique have become evident.
The technique, called deep soil mixing (DSM), requires that little
contaminated soil be excavated and brought to the land surface.
[D2,(Att.l),p.l4,Hl-3]
Response:
Without any details on DSM, it is impossible to compare this
newer, less proven procedure technically with soil-bentonite
slurry walls and to evaluate its overall implementability and
effectiveness. It seems likely that the DSN techniques would be
more difficult to quality assure during construction and less
likely to achieve performance standards approaching those of a
well-constructed, well-designed slurry wall.
17. Concern:
The Illinois Attorney General's Office states that there is no
long-term history of slurry walls at hazardous waste sites and
that slurry walls are not reliable. [A5,p.2,U2]
Response:
A review of U.S. EPA's Record of Decision (ROD) database indicates
that nineteen (19) Superfund RODs have included installation of
slurry walls as part of site response actions. In addition,
slurry walls have been implemented at non-Superfund sites. Slurry
walls are generally included as one component of an overall
remedy. When used in conjunction with ground-water extraction and
capping, U.S. EPA has considered slurry wall technology a viable
part of remedial actions which are protective of overall human
health and the environment. Although the technology's use for
environmental control is relatively new, significant experience
has been gained in implementing this technology. A few examples
of successful slurry wall implementation are included below.
A slurry wall was installed in 1984 at the Lipari Landfill in New
Jersey. Site contaminants included a wide range of volatile and
semi-volatile organic compounds. The slurry wall completely
encircled this 16-acre site. Fred Cataneo, Remedial Project
Manager, stated that since this slurry wall was installed, water
migration from the site has been reduced 90 to 95 percent. Due to
the effectiveness of containment, an innovative batch flushing
remediation method will be implemented at the site. This system
will inject fresh water into the containment area. This water
will then be extracted, in effect "flushing" out contaminants. A
treatment system will be used and treated water discharged to;a
Publicly Owned Treatment Works (POTW). Batch flushing will be
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21
conducted two to three times per year. In addition to the slurry
wall and treatment system, a cap has been placed over the site.
Another site which has implemented slurry walls is the Rocky
Mountain Arsenal site in Colorado. Contaminants consisted chiefly
of pesticide components and by-products and army agent by-products
(although several hundred of unknowns were also detected). Two
slurry walls were installed at different subsites in the early
1980s. Each one was built downgradient of the contaminant plume
in an effort to reduce migration. Each wall is approximately one-
half mile long. One wall has been extended as the contaminant
plume was detected moving around the wall's ends. In addition,
extraction wells were installed upgradient of the wall to pump and
treat ground water. Treated water is injected to the downgradient
side of the wall. Project Officer, J.D. Smith, reports that the
walls have performed well in reducing migration.
Slurry wall installation capabilities are rapidly developing.
Recently, for example, a slurry wall was installed around the
entire circumference of the South Side Landfill in Indiana. This
site is an operating sanitary landfill, currently on the National
Priorities List (NPL). A permit application renewal required that
a slurry wall and ground-water pump and treatment system be
installed. A slurry wall surrounding the site's 265 acres was
installed using Italian equipment which simultaneously digs a
trench and fills it with water to prevent collapse. The slurry
wall was installed to a depth of 100 feet and keyed into bedrock.
Another site, located in Mountain View, California, also involved
construction of a slurry wall to a depth of 100 feet. However,
this wall was not keyed into bedrock. Instead, ground water is to
be extracted from within the barrier to prevent contaminants from
leaving the site. Site contaminants included a range of
industrial solvents in the soil and ground water underneath a
semiconductor manufacturing facility. Extracted ground water will
be treated by air stripping and filtration. Installation of the
wall involved a staged approach. First, a backhoe with an
extension arm was used to excavate to a depth of fifty (50) feet.
A pair of cranes utilizing 13-ton cable grab buckets excavated to
the 100 foot depth. Initial permeability tests conducted on the
wall had a result of 1.1 X 10"8 centimeters/second. U.S. EPA will
seek to achieve a performance standard in this range at US
Ecology.
Several technical considerations are important in ensuring that
the overall alternative will provide both short- and long-term
effectiveness. The considerations include: (1) compatibility
between site wastes and the slurry wall; (2) a knowledge of site
specific requirements (geology, depth of wall, hydrology, etc.);
and (3) assurance that other components of the remedial action
work with the slurry wall to provide an effective overall remedy.
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22
In addition, quality assurance is important in assuring wall
design and installation results in a highly impermeable wall.
These considerations will be addressed in the CMI design phase.
18. Concern:
U.S. EPA should consider in-situ bioremediation as an option for
cleaning up the US Ecology hazardous waste sites.
[Bl,App.A,p.2,Hl; C4,p.6,\4]
Response:
U.S. EPA evaluated the potential effectiveness of in-situ
bioremediation as a cleanup method for both soil and ground water
at US Ecology. However, at the present time, this technology does
not appear to be feasible based on site-specific conditions. The
major organic contaminants at US Ecology are primarily chlorinated
compounds, such as tetrachloroethene, trichloroethene, 1,2-
dichloroethane, and others. To date, in-situ biodegradation of
chlorinated organics has not been demonstrated at a hazardous
waste site in either pilot- or full-scale tests. Several
technology developers claim to have demonstrated biodegradation of
chlorinated organics in the laboratory and at smaller facilities.
U.S. EPA is currently evaluating these claims and plans to test a
bioremediation technology in the near future under the Superfund
Innovative Technology Evaluation (SITE) Program.
If in-situ bioremediation is demonstrated as an effective
technology for chlorinated organic compounds, the technology could
be employed at US Ecology in the future to: (1) enhance the
remedies proposed by U.S. EPA and (2) reduce the amount of time
needed to reach ground-water cleanup goals.
19. Concern:
Slurry walls will be ineffective in containing the types of wastes
and leachate present at the US Ecology sites. The buried wastes
include some organic liquids with densities greater than water.
"At concentrations above their respective solubilities in water,
these will form separate phases which will sink to the bottom of
the water phase and adversely" affect the bottom and side liners
or slurry wall barriers. [Bl,App.A,p.2,U2; Bl.p.G.^l; Bl,
p.17,HI]]
Response:
It is unlikely that organic chemicals are present in ground water
at sufficient concentrations to form separate phases. The highest
concentrations detected in remedial investigation ground-water
samples were found in wells at the northern and eastern boundaries
of the Old Site. (One well in the center of the Old Site had much
lower concentrations.) However, even those organic chemicals
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23
detected at the highest concentrations (chloroform,
tetrachloroethene, 1,2-dichloroethane, and others) were well below
their water solubility limits. For example, the maximum
tetrachloroethene concentration in ground water was 96 parts per
million (ppm) while the water solubility of this organic chemical
is 150 ppm. Based on this comparison, there 1s little evidence to
support the theory that organic chemicals in the ground water will
sink to form concentrated layers.
II. GROUND-WATER CORRECTIVE MEASURES
1. Concern:
Additional monitoring wells are needed north and west of the New
Site to detect potential continuing or future releases of
contaminants to the ground water. [A2,p.3,§6; A5,p.6,K2]
Response:
In the Proposed Plan (page 5), U.S. EPA stated that facility
activities have contaminated ground water along the west side of
the New Site. US Ecology disputes this claim [D2,p.14,^2] by
referencing data from 1987 and 1988. Data from 1987 showed
contamination in the ground water west of trenches 23 and 24 in
wells G-131, G-145, and G-146. Contaminants were
tetrachloroethylene (PCE) and methyl ethyl ketone (MEK). Data
from 1988 did not show contaminants in the ground water in those
wells. US Ecology labels the 1987 results "anomalous". However,
soil gas and ground-water sampling results (in G-131) from
November and July of 1986, respectively, indicated the release of
methylene chloride, trichloroethylene (TCE), PCE, and chloroform
at locations along the north and west sides of the New Site.
Please refer to the Final Remedial Investigation (RI) Report
(pages 4-46 and 4-55) and to analytical data in Appendix C to the
RI report. Page 4-55 states that "these data indicate that a
ground-water contaminant plume, if one exists, may be isolated
between G-145 and G-146." In 1987, well water from G-109 and
G-147 contained the contaminants chloroform and PCE. Based on the
comment and the data, U.S. EPA will require submittal of a work
plan to install additional monitoring wells north and west of the
New Site to decrease the existing spacing between wells G-160, G-
161, G-162, G-146, G-169, G-170, G-145, and G-147.,
2. Concern:
Additional monitoring wells are necessary south and east of the
New Site to detect potential present or future releases to ground
water. A contingency plan should specify actions to be taken in
the event a new release is detected. [A5,p.6,H2; A5,p.7,Ul] \
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24
Response:
There are at least eighteen (18) monitoring wells (for Indicator
parameter evaluation, assessment, and RI activities) south of
trenches 20, 21, and the three 18EW trenches. (See page 5-14 of
the RI report.) This is a linear distance of about 800 feet.
Well spacing appears to be less of a concern in these locations
than east of trenches 14c, 15, and 16 B of the New Site, west of
trench 22, and south of trench 23. US Ecology will be required to
submit a work plan to reduce well spacing at these locations.
Under the RCRA program that IEPA is monitoring and directing, the
"contingency plan" for actions to be taken if significant
increases (or decreases in the case of pH) over background water
quality are detected in specific wells, is described in 35 111.
Adm. Code 725.193. Resampling of ground water would be done to
confirm the initial results, a ground-water quality assessment
plan would be submitted to IEPA, and the facility would be
required to implement an assessment program capable of determining
the rate and extent of the ground-water contamination and the
concentration of the hazardous constituents. Upon confirmation of
a new release of contaminants from the facility, corrective action
would be addressed either under the existing corrective action
order or under an lEPA-issued post-closure permit.
3. Concern:
To limit or possibly halt the commingling of chemical and
radioactive contamination, and the eventual discharge into Trout
Lake, IDNS recommends U.S. EPA consider installing additional
extraction wells south and southeast of the Old Site. [A3,p.2,^1;
A4,p.2,12; E2,p.71,12]
Response:
US Ecology modeled ground-water flow to assist in predicting the
transport and concentrations of contaminants over time
specifically in the vicinity of the Old Site for the Feasibility
Study (FS) report. (See the FS for Ground-Water Remediation
Vol.1, Section 4.4.3 and Vol. II, Appendix C.) The locations of
the extraction wells and subsurface drains depicted on page 4-40
of Vol. I were selected by US Ecology based on modeled ground-
water flow which indicated those were the optimum locations,
considering proposed ground-water extraction rates, to
specifically address this concern. However, further modeling will
be required under the CMI design phases. U.S. EPA is also
cognizant of the concerns that the ground-water extraction system
implemented under corrective action must not negatively impact
existing ground-water flow conditions at the LLRW site. Modeling
will be required to address these concerns as well.
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25
4. Concern:
One commenter suggests placing additional extraction wells in any
permeable saturated units encountered beneath the Toulon Sand
above the bedrock to capture contaminants which could "sink" below
the capture system, and suggests recalculation of the estimated
total water flow from extraction wells and subsurface drains.
[A2,p.2,§2b-c]
Response:
This concern cannot be discounted and will be carefully evaluated
during the design phase of the CMI. The draft FS for ground-water
remediation (Vol.1, p.4-39) discusses placement of well screens
(also referred to as subsurface drains) at an elevation four (4)
feet above the bottom elevation of the Toulon Sand. The stated
reason was that this elevation was "adequate to capture the Old
Site plume without significantly affecting the regional flow
directions outside the drain." The final extraction well design
will have to consider the need to capture "sinkers" and
"floaters", to reduce additional mixing of the chemical plume with
the radionuclide plume, and to minimize potentially adverse
effects on regional ground-water flow. Based on the numbers,
locations, and pumping rates of the wells in the finalized
extraction well design, a recalculation of estimated total water
flow will be possible.
5. Concern:
The exact locations where U.S. EPA is proposing that US Ecology
place additional extraction wells is unclear. [A2,p.2,§2e;
B6,p.II-3,§8]
Response:
In the Proposed Plan (p.22) U.S. EPA states that US Ecology must
modify its proposed extraction well system to "include placement
of additional extraction wells at or near plume boundaries which
will hydraulically prevent further migration of contaminated
ground water." Conceptually it is clear that the extraction well
design must capture the plume and prevent its expansion. Further
modeling will indicate the optimal numbers and locations (i.e.,
the detailed design) necessary to accomplish the established
design goals.
6. Concern:
A commenter supports the proposed alternatives for extraction and
treatment of contaminated ground water, but says the effectiveness
depends upon immediate implementation. [Al,p.l,H6; E2,p.18,^4]
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26
Response:
Based on ground-water remediation activities conducted at U.S. EPA
Superfund sites, experience has shown that early implementation of
a ground-water extraction and treatment system is advantageous for
both controlling expansion and for remediation of the
contamination in a more timely manner. Early installation and
operation of a limited extraction system which is partially
effective (i.e., not achieving all the established design goals)
is preferable to delaying installation of the extraction-well
system for months or years during extensive RI/FS and design and
modeling phases. In fact, because of the actual data provided
(e.g., ground-water levels and flow rates) during operation of a
more limited ground-water extraction system, the iterative process
of developing an effective, long-term, final design is advanced
greatly. Design and installation of the extraction wells and
treatment system is presently estimated to take eighteen (18)
months.
7. Concern:
U.S. EPA's preferred alternative for ground water is unacceptable
because it will not provide long-term effective or permanent care
to prevent or minimize the release of hazardous substances and
will not protect the water supply. [A5,p.l,U2; B3,p.1,^4;
E2,p.34,11]
Response:
U.S. EPA respectfully disagrees with these commenters. The source
control measures, when completely and acceptably implemented and
maintained, will prevent or minimize the release of hazardous
waste, hazardous constituents, and substances from burial
trenches. In conjunction with the source control components, the
ground-water extraction system will be designed to stop plume
expansion while remediating the contaminated ground water
maintained under US Ecology property. US Ecology will be required
to maintain and operate the ground-water extraction and treatment
system until the company can demonstrate that established ground-
water protection standards (GPS) have been achieved for the
remaining ground water beneath the landfills and that the residual
levels of contamination left in the ground water will not pose a
future threat to human health or to the environment. Therefore,
ground-water and surface water supplies adjacent to US Ecology
will be protected.
8. Concern:
IDNS monitoring data indicate that radioactive contaminants have
migrated to the ground water east of Trout Lake and suggest that
chemical contaminants will do the same. Therefore, existing water
supplies to the east of the US Ecology site may be threatened by
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27
migrating contaminants from the LLRW and Old Sites. [A5,p.8,^l;
A5,p.5; A2,p.2,§2f; B6,p.1-4,1(1 and p.I-7,\l; E2,p.55,\2]
Response:
U.S. EPA is aware and concerned about data indicating that
radioactive contamination (tritium) is present east of Trout Lake.
RI data confirmed also that some chemical contamination from the
Old Site ground-water plume was discharging to Trout Lake. These
data necessitate an effective system of extraction wells designed
to prevent further plume expansion as soon as technically
feasible. Some existing monitoring wells may have sufficient
casing diameter and construction and be appropriately located to
be used as interim or final design extraction wells.
Unfortunately, however, the delays in actually initiating the
ground-water extraction and treatment system on site will most
likely be associated with design and construction of the treatment
system itself and with obtaining a permit for discharge of treated
ground water to surface water. Current tritium concentrations are
not yet a significant concern (see response to concern VI.1).
However, ongoing ground-water monitoring will continue to assess
concentrations and the effectiveness of all source controls
implemented.
9. Concern:
The glacial units beneath the US Ecology sites are complex and do
not function as a "single heterogeneous unit" with respect to
subsurface contaminant migration. The site hydrogeology has not
been adequately defined. Without this information, migration
routes and velocities of plumes cannot be defined sufficiently to
develop an adequate ground-water cleanup plan. [84,1(2; B6,p.I-l,
H2 through 4 and p.1-2,1(1-2; E2,pp.44-45]
Response:
The following statement is included in the RI report on page 4-96:
"In general, the glacial deposits can be treated as a single
heterogeneous hydrogeologic unit." This sentence followed several
pages (e.g., 4-15 through 4-23; 4-95) documenting the observed
heterogeneity of the geologic units which comprise the glacial
aquifer. The RI report states (page 4-95) that the ground-water
flow is "controlled by variable ground surface topography . . .
and by the heterogeneous hydraulic conductivities of the various
hydrogeologic units" in the glacial aquifer. The fact that the
geology is complex does not eliminate from consideration use of a
ground-water extraction system for remediation purposes. Complex
hydrogeology simply makes the design phases of the extraction well
system more challenging. Initial ground-water modeling done for
the feasibility study indicated that the glacial aquifer, although
complex lithologically, could be modeled credibly as a single
layer with heterogeneous zones (see pp. C-18 to C-33; C-39 to C-
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28
65; and C-82 of Vol. II of the draft Ground Water FS Report).
Implementing an effective extraction well system is an iterative
process. Characterizing the geology and ground-water modeling
provides limited information. Actual installation of wells and
observation of the effects of pumping on water levels is the final
step in design.
10. Concern:
U.S. EPA should identify sites where a ground-water extraction
system (like the one proposed for US Ecology) has worked
effectively in such a complex geological environment. [64,^3;
E2,p.37,f2]
Response:
Utilization of a ground-water extraction system for halting plume
expansion and remediation of ground-water contamination is not
uncommon. Geologic complexity associated with glacial activity is
by no means unique to the Sheffield, Illinois, area. Many areas
of the central and eastern United States have been affected by
glacial erosional and depositional activity.
U.S. EPA has developed a summary of pump-and-treat applications
nationwide in a March 1990 document (EPA/600/8-90/003). Locations
(by site name and state) where this technology has been used in
glacial sediments include: Des Moines, Iowa; Verona Well Field,
Michigan; General Mills, Inc., Minnesota; Amphenol Corp., New
York; and Black and Decker, New York.
11. Concern:
U.S. EPA's assertion that the cleanup of the US Ecology could
continue "indefinitely" is not consistent with the Agency's
positions under either CERCLA or RCRA. Proposed U.S. EPA rules
for corrective action at RCRA sites require that the Agency
"specify a schedule for .... completing remedial activities."
[D2(Att.l),p.l7,K3-5]
Response:
Existing statutory provisions and regulations regarding corrective
action under RCRA, and with which this action must be consistent,
require the owner/operator to, among other things:
1. After the Regional Administrator of U.S. EPA has specified
the ground-water protection standard (GPS) in a permit (in
this case under a Consent Order) (40 CFR §264.100(a)), the
owner/operator must implement, within a specified time, a
corrective action program that prevents hazardous
constituents from exceeding the GPS for individual
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29
constituents at the established compliance point by removing
or treating them In place" (40 CFR §264.100(b) and (c);
2. Establish and implement a ground-water monitoring program to
demonstrate the effectiveness of the corrective action
program (40 CFR §264.100(d)); and
3. "Continue that corrective action for as long as necessary to
achieve compliance with the ground-water protection
standard" (40 CFR §264.100(f)). The subpart states that
corrective measures may be terminated if the owner/operator
can demonstrate that the GPS has not been exceeded for a
period of three consecutive years as indicated by the
ground-water monitoring program established under 40 CFR
264.100(d) to demonstrate the effectiveness of the
corrective action program.
US Ecology is subject to regulations requiring the facility to
eventually obtain a post-closure permit. It is, therefore,
logical to be consistent with the existing requirements for
permitted facilities.
If US Ecology is concerned about the prospect of perpetual
extraction and treatment of contaminated ground water, it is
certainly to the company's advantage to: (1) design, install, and
maintain the source control components of the selected corrective
measures to be as effective as possible; (2) implement, as soon as
technically feasible, the ground-water extraction well system and
treatment system meeting the guidelines established herein; and
(3) consider voluntarily implementing available or emerging
technologies to enhance recovery of organic contaminants (e.g.,
soil vapor extraction, in-situ bioremediation, etc.) and achieve
the GPS within a shorter timeframe.
12. Concern:
A 30-year period will not be sufficient to clean ground water if
the source of contamination remains in place. [B5,p.2,U4;
E2,p.42,12]
Response:
Please refer to the response immediately above regarding US
Ecology's responsibility to undertake corrective action and to
remediate the ground water and the time involved to do so.
Because the contaminant sources will remain in place, it is
essential that all components of the selected corrective action
are well designed, carefully installed, and properly maintained
and operated to control future releases from the Old and New
Sites. The main objective of the CMI will be appropriate design
and effective implementation of each component of the remedy. As
a result of these corrective measures, contaminated ground water
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30 A
will be addressed to achieve protection of human health and the
environment.
13. Concern:
i
It appears that ground-water cleanup will continue Indefinitely.
Without a defined end point, the success or failure of the cleanup
plan will be difficult to measure. [B5,p.2,<|[4; E2,p.42,\3]
Response: _ - ;
"•i
The primary objectives of the selected remedy are: (1) to halt
further contaminant plume migration; and (2) to effectively stop
further release from the sources of contamination. tA secondary
objective is remediation of the contaminated ground water while
the contamination is hydraulically controlled from further
expansion. The effectiveness of the extraction well system will
be gauged by continued regular ground-water monitoring of wells
inside and outside of the plumes to mon(,itor-j)oth for;plume
concentrations (increases or decreases^ and ^expansion or shrinkage
of the plumes.
III. SITE GEOLOGY AND HYDROGEOLOGY • . , '"{
1. Concern:
Steve Barlow, a resident of Princeton, Ill.inpis, and'.other
commenters, argued that because of the presence of numerous
cracks, joints, and fissures in the bedrock ielow the US Ecology
site (which contains the Old Mississippi River Bed Aquifer), the
contaminants are moving through the glacial fill toward the
Princeton Bedrock Valley that many people depend on as a source of
drinking water. [C2,p.l,1[4 and p.2,^1; Bl,pr.3,H2; E2,p.56,^2]
Response:
The RI report contains three years worth of ..ground,-,water data from
numerous monitoring wells. When this RI investigation began in
June 1986, 226 wells existed on site. Nineteen (19) mere wells
were added in late 1986 and thirty-six (36) bedrock and glacial
wells were installed in 1988. Bedrock contamina^n^has been
shown to be minimal except in the G-120 area and north slope seeps
where the #7 coal seam contains contaminated-ground water. Ground
water is being drained to the north slope area by pipes inserted
in the coal seam. Contaminated water has been collected in this
manner for a couple of years and sent off site for treatment and
disposal. Now, however, an on-site treatment plant is being
constructed to properly handle the extracted water on site and
treat it to State-approved contaminant discharge limits. There is
no evidence to suggest contamination of the bedrock in the north
slope area wells (glacial or bedrock) except the G-120 assessment
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31
well area. The contamination in the G-120 area is predominantly
above and in the #7 coal. Because empirical data show limited
bedrock ground-water contamination on site, geologic conditions
slow vertical movement of ground water, and eventual
implementation of a ground-water extraction well system will halt
plume expansion and remove and treat bedrock and glacial ground
water on site, the threat of contamination of any drinking water
supplies will be minimized if not eliminated.
2. Concern:
Roy Mahnesmith and Edward Glubczynski posed the question of what
effect catastrophic events (i.e., statistical outliers) and the
presence of unknown materials might have on containment structures
and hydrogeology at the site. [C3,§3]
Response:
Although the records are incomplete regarding hazardous wastes
disposed of in the Old Site trenches, considerable information
exists on the general types of waste buried there. Considerable
information is known about the types of hazardous constituents
that have been released to ground water by infiltrating surface
water since the Old Site ceased receiving waste in 1974. The
hazardous constituents in the ground water are essentially a
finger print of the waste buried in the landfill and after sixteen
(16) years of surface water leaching constituents and of drums
leaking to ground water, future significant changes to the general
composition of the existing chemicals in the ground water are not
anticipated. Future releases will be reduced by the placement of
an effective landfill cap on both the Old and New Sites.
Catastrophic events, such as very heavy rainfalls, can cause
erosion of landfill caps (which can be repaired) and a rise in the
ground-water table. During the CMI design phases, contingencies
will be developed for addressing such events should they occur.
3. Concern:
One commenter suggested that coal exploration borings may have
been drilled in the areas of the Old Site, New Site, and LLRW site
prior to waste disposal activities at the US Ecology site. These
exploratory borings would have penetrated to the Herrin Coal, and
it is likely that the borings were never plugged or backfilled.
If present, the borings would provide a direct pathway for
contaminant migration from waste disposal areas into the glacial
aquifers and deeper into the bedrock below the sites. [B2,p.2,H2;
B7,pp.11-14; C2,p.l,\4; C10,p.2,Ul; E2,pp.27-31]
Response:
This is a valid concern. However, RI ground-water data suggest
that the potential impact of unplugged coal exploratory borings on
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32
the vertical migration of contaminant from the Sheffield chemical
disposal sites is very limited. This may be the case for many
reasons: (1) The number of boreholes for coal exploratory
purposes that are actually now covered with hazardous waste
disposal cells is small (possibly as many as eight to ten).
Compared to the total landfilled area of about forty-five (45)
acres, the effect from these boreholes (each two or three inches
in diameter) is not expected to be significant; (2) The
"unplugged" boreholes are certainly not unobstructed conduits for
contamination. Upon withdrawal of drilling equipment from an
exploratory borehole, some drilling muds would remain and become
compacted in the borehole, other consolidated materials above
bedrock would be expected to collapse into the corehole, and the
reworking of glacial materials by heavy equipment during burial
trench construction activities would also contribute to reducing
the potential impact of abandoned boreholes; (3) The RI data
suggest ground water moves more readily in a horizontal direction
through the glacial sediments than vertically into the lower
permeability bedrock. For whatever reason, ground-water data from
bedrock wells, especially in those screened in the Nos. 6 and 7
coals, generally show little or no contamination compare to
glacial wells. It is difficult to definitively correlate any of
the contamination in bedrock wells with the known approximate
locations of the exploratory borings. If any of these boreholes
are acting to any extent as contaminant migration pathways, the
components of the corrective action for both source control and
ground-water remediation will reduce those effects over time. To
further discount or test the potential validity of the migration
pathway hypothesis, US Ecology has proposed to install seven (7)
new monitoring wells screened in the #6 coal (i.e., the deepest
bedrock penetrated by the exploratory borings). U.S. EPA is
reviewing that proposal now prior to approving it.
4. Concern:
U.S. EPA owes the public a "debt of explanation" for either
failing to identify mining company test borings near the waste
sites or withholding this information from the public.
[CIO,p.2,12]
Response:
Under a RCRA corrective action, U.S. EPA directs studies. U.S.
EPA approved US Ecology's RI work plan in 1986 which included a
search for all existing borehole data. The chronology of the
search for these data was presented by US Ecology in its comments
to the Proposed Plan [D2,Att.l,p.l5] and more fully in a September
11, 1990, document. US Ecology submitted logs of exploratory
boreholes and their approximate location in September 1990. U.S.
EPA neither knew of nor withheld any information regarding these
exploratory boreholes.
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33
5. Concern:
US Ecology contends that ground water west of the New Site Is not
contaminated, based on the results of numerous samples collected
after January 1987. [D2,p.l4,2H; D2(Att.l),p.l,!2]
Response:
Please refer to the response to concern II.1 which addresses
lEPA's request for additional monitoring wells based on soil gas
survey results west and north of the New Site. There 1s
sufficient documentation to confirm past releases and enough
doubts about the adequacy of the present number of wells to
require a closer well spacing In those locations.
6. Concern:
US Ecology contends that there Is no evidence to support migration
of Inorganic contaminants to Trout Lake, as implied by U.S. EPA's
Proposed Plan. [D2,p.14,1(3]
Response:
U.S. EPA concurs with this statement in that it is difficult to
say definitely whether or not the inorganic contaminants in the
Trout Lake water resulted from strip-mining activities primarily
or could have migrated from the Old Site in ground water
discharging to the lake. The inorganics under discussion were
barium and zinc. What is virtually certain is that PCE, at 5
/jg/L, was related to the Old Site plume discharging to Trout Lake.
7. Concern:
U.S. EPA's Proposed Plan incorrectly implies that inorganic
compounds detected in ground water, surface water, soil, and
sediment are site-related. Background concentrations an the
effects of adjacent coal strip mining activities have not been
considered. [D2(Att.l),p.l,H4; D(Att.2),p.l3,1fl-3]
Response:
US Ecology had failed, prior to the Soils Addendum to the RI
report, to successfully argue its own case (i.e., to show that
observed levels of inorganic compounds are more likely related to
strip-mining than waste disposal activities). Many of the wastes
accepted for disposal contained inorganics and, while agreeing
with US Ecology that strip-mining activities have affected the
concentration and distribution of inorganics, the origin of these
must not be automatically assumed to be non-site related. USX
Ecology has stated on page 5-1 of the RI report that "organic and
inorganic constituents have migrated from burial trenches and have
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34
entered shallow ground water in three areas" (underline added here
for emphasis).
8. Concern:
It is clear that contaminants are migrating from ground water to
Trout Lake. A complete study of the hydraulic interaction between
ground water and the lake should be conducted. Is IONS or US
Ecology responsible for developing hydrogeologic data and
investigating contaminant levels for Trout Lake? [B5,p.2,\3;
B6,p.II-3,§9; E2,p.41,K4]
Response:
US Ecology has conducted a study for IEPA in the area north, east,
and south of Trout lake. In December 1989, several borings were
completed and new monitoring wells were installed. This was a
one-time study to further characterize the hydrogeologic
conditions in the southern half of Trout Lake. A report on the
additional studies is expected to be submitted to IEPA in the near
future. Ground-water samples were taken from these new wells and
were analyzed for both radionuclides and organics.
Under the Consent Order with IDNS, US Ecology is required to
sample specific IDNS monitoring wells on a stated regular basis
and to analyze for the presence and concentration of specified
radionuclides and organics. US Ecology is also required to
analyze ground-water samples in some instances for the full list
of 40 CFR Part 264 Appendix IX parameters.
9. Concern:
Contradicting statements are made in the RI report regarding
"laterally continuous" geologic units and fractures and joints in
those low-permeability rock sequences. [Bl,p.25,^4; 81,p.8,^2;
Bl,p.15,^2]
Response:
A basic concept in geology is that of the law of original
continuity wherein the same sedimentary stratum is observed to be
present in borings from place to place. Lateral continuity of a
geologic unit (e.g., the Farmington Shale) beneath the landfills
and the presence of joints or fractures within that unit are not
mutually exclusive conditions.
10. Concern:
Some commenters criticized the RI reports (e.g., no easy way to
locate the 200+ monitoring wells; figures are too small; geologic
cross-sections are too simplistic, although "a wealth of data is
contained on the bore logs"; wanted additional bore holes to
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35
better define bedrock contours, etc.; over simplifications of
glacial geology and hydrology; potentiometrie surface maps may be
misrepresenting actual conditions; data points are not labelled or
are inaccurate; maps and figures are poorly labeled and difficult
to read; appendices do not include all data collected; the
reference list is incomplete; material in the text is attributed
to the wrong source; and contradictory information's presented.
[Bl,pp.9-13; B5,p.1,15-7; B5,p.2,Hl-2; BGip.VB.^nd p.1-6,1(1-2;
E2,pp.39-41 and pp.43-51] ? -*:.
•'. •'• ''j £0 ' , ":
Response: " >'• •*• :< '•'•
The Final RI Report was approved by U.S. EPA in April 1989,
following its original submittal (March 18, 1987), the appended
version (October 5, 1988) after completion of,one, year of
additional study, and two subsequent revisions YeWested by U.S.
EPA. It is not easy to present the vast amount i>f data generated
for this RI report without some simplification "orgeneralization
of hydrogeologic conditions found on site. The gb%l in the RI
process is to distill from the RI study thennfordsjion necessary
to make decisions regarding corrective measures "selection. U.S.
EPA RI/FS guidance states: "the objective of the Wl/FS process is
not the unobtainable goal of removing all uncertainly,1 but rather
to gather information sufficient to support an informed risk
management decision regarding which remedy appears1 %o be most
appropriate for a given site." Choices made durini the RI
investigations, "like the remedy selection itseTf:,-rinv|qlve the
balancing of a wide variety of factors and thW ex^cisB of best
professional judgment" (EPA/540/G-89/004; 'OctoBer:¥98&; p.1-3).
Based on this guidance, U.S. EPA determined tttsC^-he Final RI
Report contained and presented sufficient data (e.g., borelogs,
ground-water analyses, plume dimensions, etc.) to develop,
evaluate, and make decisions regarding remedial alternatives.
With respect to the specific comments raised by Ms.; Morse (B6),
most comprise a summary and reintroduction of comments she
submitted as a former employee of the State of Illinois. In fact,
her submittal attaches the complete list of IEPA comments on the
October 5, 1988, draft of the RI report transmitted to U.S. EPA on
February 2, 1989. All of these comments were reviewed by U.S. EPA
before approval of the Final RI Report in April ftSJJ". US Ecology
satisfactorily addressed all significant comments1 Wresponse to:
(1) Revisions requested by U.S. EPA prior to receitfV orf IEPA;
comments; (2) A second set of revisions requested py: U.S. EPA
after receipt and inclusion of most IEPA comments;"1 a^nd (3) Direct
responses to IEPA on each issue raised in their February 2, 1989
comments. It is not useful to itemize herein the responses to all
these comments. They are already present in the record.
U.S. EPA, using professional judgment, approved the^Ffnal RI
Report after determining that sufficient informaticSi had been"
generated under the RI to allow informed decisions to'be made
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36
regarding the corrective measures study and that the Information
was adequately presented In the RI report. It 1s U.S. EPA's
position that sufficient information is available to allow
technical decisions to be made in selecting the corrective
measures appropriate for this facility.
11. Concern:
The Old Site plume has migrated to bedrock in spite of what US
Ecology says on page 5-34 of the RI report. See page 5-22, Table
5-5.
Response:
The RI report states (p. 5-34) "it can be concluded that the plume
remains confined primarily to the glacial aquifer and has not
penetrated into the bedrock to any great extent." Table 5-5 does
indicate the detection of four organics in four bedrock wells (not
all four in the same well). Three of these chemicals are common
laboratory contaminants and the other, benzene, was found in only
one well at 14 ppb. All concentrations were below 37 ppb. These
concentrations are minimal when compared, for example, to glacial
aquifer contaminant concentrations (see Table 5-4, p. 5-17) of up
to 180,000 ppb for chloroform. No one is stating that the bedrock
aquifer is unaffected by releases. However, empirical data
support the first sentence of this response. The distribution of
contamination indicates that the ground water transporting it
shows a greater tendency to move horizontally than vertically
(i.e., through unconsolidated glacial sediments rather than into
fractures in bedrock).
12. Concern:
One commenter described several problems with hydraulic gradients
presented in the RI report; gradients are based on incorrect
calculations of screened intervals or well depth; hydraulic
conductivity values attributed to one unit are based on data from
a different unit; vertical gradients were not calculated from
supplemental RI well data as planned; and no ground-water
velocities or horizontal gradients are provided. [B6,p.1-4,^3 and
1-5,HI; E2,pp.48-51]
Response:
It appears these comments are based on those originally submitted
by IEPA regarding the October 5, 1988, draft RI report. All
hydraulic gradients were recalculated for the Final RI Report.
13. Concern:
Ground-water surface maps presented in the RI are inaccurate
because data used to construct the maps were collected over too
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37
long a time span and data from different glacial units are
combined. [B6,p.1-4,\3 and p.1-5,HI; E2.p.48,H3-4]
Response:
Certainly, the time span over which ground-water levels are
recorded in monitoring wells can affect the final map produced in
some cases. Readings were taken by US Ecology for all wells
usually on one day, when possible, but never over a time period
exceeding 48 hours. For example, the June 1988 water levels were
taken on June 6 and 7. Wells screened in different glacial units
undoubtedly will cause some minor inaccuracies. However, the data
generated during the RI, using many wells and water level readings
from three years, compare favorably to potentiometric maps from
the site from as early as 1976 to the present and show similar
ground-water flow directions and gradients. These maps also
generally agree with those produced in studies of the LLRW site.
14. Concern:
Data collected during the RI (e.g., core descriptions, drilling
water loss, and influx records) refute the claim that shallow
bedrock strata act as an impediment to ground-water flow.
[B6,p.1-2,13; E2,p.45,H3-4]
Response:
While review of such records kept during installation of
monitoring wells may indicate this is true in some instances, the
fact remains that empirical data from ground-water sampling and
analysis in bedrock and glacial wells generated during the RI show
limited vertical migration of contamination. The data suggest a
much greater inclination to move laterally through shallow,
unconsolidated glacial sediments than vertically through the
bedrock.
IV. REMEDIAL INVESTIGATION AND FEASIBILITY STUDY
1. Concern:
A few commenters questioned the reliability of the RI as
pertaining to the ground-water sampling because of. the extreme
drought conditions that were present in the county dating back to
1986. [Cl; C3,2§; Bl,p.22,Hl; E2,p.53]
Response:
Ground-water sampling has been conducted at US Ecology since 1981
and continues to be done. Results are sent to IEPA on a regular
basis for assessment and indicator parameter evaluation monitoring
wells. Wells which initially detected releases of hazardous
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38
wastes or hazardous constituents leading to the 1985 Consent Order
to perform corrective action did so prior to the drought
conditions and have continued, when sampled, to show evidence of
contamination. Drought conditions could have the following effect
on the ground-water table and the results from the sampling and
analysis in the wells: (1) A general lowering of the water table
potentially leaving some hazardous constituents adhering to soil
particles; and (2) Less infiltration of surface water through the
buried wastes and, therefore, lower levels of constituents in the
ground-water samples. A review of ground-water contours under the
Old Site, on October 20, 1976, (p.4-19 of RI report) and June 1988
(p.4-99 of the RI report) show that the elevations (west to east)
were about 760 to 730 feet and 750 to 730 feet, respectively.
These pages indicate some decreases in water table elevation over
the twelve (12) years, but the changes in the contours on the four
glacial aquifer maps are not striking. The contamination has been
shown to be present by reliable sampling and analytical techniques
and the effect the drought conditions had on the concentrations is
difficult to assess. The contaminated ground water requires
remediation and it must be hydraulically controlled to stop
further plume migration.
U.S. EPA obtained annual precipitation data from Moline, Geneseo,
Walnut, Tiskilwa, and Kewanee for the years 1980 to 1988. These
data do not support fully the claim that drought conditions
affected sampling results. Annual precipitation for most sites
(Kewanee is the exception) tended to exceed long-term averages
during this period.
2. Concern:
Climatological data presented in the RI report (such as average
and maximum 24-hour rainfall) are incorrect and underestimate real
conditions. This could have an effect on hydrologic modeling of
the site and on the design of corrective measures. [B7,p.18,^1]
Response:
The commenter has pointed out that certain data contained in the
RI report were incorrect (e.g., the mean annual precipitation for
Moline, Illinois, was stated to be 35.70 inches rather than 35.83
inches and the 24-hour rainfall was stated to be 5.7 inches rather
than in excess of six (6) inches). Further hydrologic modeling of
the sites will be performed during the CMI design phases. Data
inputs will be updated as necessary.
3. Concern:
The RI report does not include any geologic maps of the site, such
as a bedrock geologic map. [B7,p.18,^2]
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39
Response:
While this Is true, many cross section maps depicting the
thickness and distribution of geologic strata are included for the
Old and New Sites. These, along with the bedrock contour map,
were sufficient to provide an adequate two and three dimensional
picture of the geology.
4. Concern:
Several maps in the RI report are computer-generated and do not
accurately represent site conditions. [B7,p.19,^1; B6,p.1-3,1(2]
Response:
Subsurface maps, whether drawn by hand or computer generated, are
based on a limited number of data points. A map drawn by one
geologist or hydrologist may not exactly resemble that drawn by
another using the exact same data. The goal, however, is to
produce maps which, in spite of their inherent inexactness,
provide tools which will allow decisions to be made regarding the
corrective measures selection. The RI report has provided the
detail necessary for technical decisions. The U.S. EPA has
provided comments to US Ecology on Figure 4-22 of the RI report.
That bedrock topography map indicates a closed-contour depression
in the bedrock which does seem illogical and may be a result of
too few data points at the east end near Trout Lake.
V. INTERACTIONS BETWEEN CHEMICAL AND RADIOACTIVE WASTE
1. Concern:
Commenters say that the preferred ground-water alternative does
not address remediation of ground water contaminated with
radionuclides. They suggest that extracted water from wells south
and southeast of the Old Site be monitored and treated for
radioactive contamination, if such contamination is found.
[A2,p.2,§2d; A3,p.2,U2i A4,p.2,1(3; E2,p.71,13]
Response:
U.S. EPA does not agree with the first part of the comment. The
very last item in Section V of the Proposed Plan (page 22) states
that US Ecology must:
"Provide for regular sampling of the extracted ground water
for those radionuclide parameters in Table 5-7 of the RI
plus 1-129. A plan and schedule for these sampling
activities will be required."
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40
Regarding the second portion of the concern raised, U.S. EPA
stated in the Proposed Plan (page 36):
"The 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."
South or southeast of the Old Site are the locations where the
chemical/radioactive ("mixed") plume is most likely to be
encountered.
2. Concern:
Commenters are concerned that alterations in the ground-water flow
patterns will cause radioactively contaminated ground water from
the LLRW site to combine with chemically contaminated ground water
from the Old Site. [A5,p.4]
Response:
This is a valid concern and certainly will be an important factor
in designing the extraction well system (e.g., number of wells,
well locations, pumping rates, possible use of reinjection wells,
etc.). The CMI will include additional ground-water modeling as
various designs are considered to address concerns of U.S. EPA and
several commenters. The modeling already done by US Ecology (p.
4-39 of the ground-water FS) indicated a desire to limit southerly
and southeasterly flow: "The eastern edge of the drain is
designed to prevent further migration of the plume toward the
tritium plume." Also on page 4-39, US Ecology discusses design
considerations related to adequately capturing "the old site plume
without significantly affecting the regional flow directions
outside the drain."
3. Concern:
Commenters share concerns of the Illinois Department of Nuclear
Safety (IDNS) about ground-water flow and problems this may cause
at the Low Level Radioactive Waste (LLRW) site. They suggest that
U.S. EPA select a remedy that will not adversely affect the LLRW
site. [A2,p.l,§ld; A5,p.8,H2; Al,p.l,K7; E2,p.19,12; E2,p.55,ll]
Response:
Please refer to the response immediately above.
4. Concern:
The mixture of radioactive and chemical contaminants, pumped from
the Old Site, will complicate safe handling and treatability of
extracted ground water. [A5,p.4]
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41
Response:
U.S. EPA concurs with this statement. However, 1t 1s unacceptable
to allow continued expansion of the Old Site plume of contaminated
ground water. U.S. EPA's position remains unchanged: the Old
Site plume must be managed so as to preclude further plume
expansion and the contaminated ground water must be extracted and
treated until established ground-water protection standards are
achieved In spite of the presence of radionuclides mixed In with
the chemical plume. The details of how the extracted water will
be managed will be determined during the CMI design phase.
5. Concern:
US Ecology believes that: (1) draft U.S. EPA guidance on
"Corrective Action for Solid Waste Management Units (SWMU) at
Hazardous Waste Management Facilities11 supports a position of non-
action on portions of the ground-water plume that are contaminated
with both chemical and radioactive wastes and (2) natural
attenuation is an appropriate remedy for this part of the plume.
[D2,p.lO,12]
Response:
The "guidance" cited by US Ecology is from the Proposed Rule (55
Federal Register 30798) dated July 27, 1990. U.S. EPA disagrees
with this comment by US Ecology on page 10 of their submittal. US
Ecology quotes preamble language from the proposed rule (page
30825) to support their position. However, US Ecology's argument
is unsupportable because: (1) It is unlikely that, in this
situation, "ground-water cleanup standards can be achieved through
natural attenuation within a reasonable time frame"; (2) The
contaminant plume is already greater than twenty-three (23) acres
in size, contains multiple contaminants of concern to human health
and the environment, including radioactive constituents; (3)
tritiated water is already detected in ground water east of Trout
Lake and the RI report contains data showing organics from the Old
Site plume have been discharged to Trout Lake; and (4) The plume
will continue to increase in size until an extraction well and
treatment system is installed and operational under the CMI.
These points argue for active restoration of the contaminated
ground water and for hydraulic controls on further migration of
the plumes.
6. Concern:
Commenters recommend that U.S. EPA require US Ecology to show
(through modeling and monitoring) that construction of the slurry
walls and cap will have no adverse effects on the known hydrology
of the radioactive site. [A3,p.3,11-2; A4,p.3,12-3; E2,p.73,12-3]
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42
Response:
US Ecology will be required to conduct additional ground-water
modeling during the design phase of the CMI. Prior modeling for
the ground-water FS did not take into account the effects of a
slurry wall around the Old Site on the hydrology of the
radioactive site. Modeling will provide insight into the probable
effects on the ground-water elevations and flow directions in the
vicinity of the LLRW site. Upon implementation of the source
control components, piezometers will be installed (or existing
ones could be used, if appropriately located) to assess, on a
regular basis, the effects on the hydrology. The design of the
extraction well system for ground-water remediation will be such
that increased or decreased pumping rates from suitably located
wells will assist in maintaining the desired design water table
levels.
7. Concern:
Commenters recommend that U.S. EPA require a sequential approach
during application of ground-water remediation and source control
measures so that any effects of either activity on the
radiological site can be distinguished and assessed. [A3,p.1,^4;
A4,p.l,13; E2,p.70,13]
Response:
U.S. EPA believes that it is necessary to install extraction wells
in the whole plume rather than sequentially extracting and
treating portions of the plume, as is suggested by this comment.
The commenter can be assured that additional ground-water
modeling, prior to installation of components, will be performed
and ground-water levels will be monitored to assess potentially
adverse effects on the hydrology after installation. A
contingency plan will be prepared to respond to any observed
adverse effects.
8. Concern:
Laboratory analysis of ground water contaminated with both
radionuclides and chemicals poses unique problems. Potential
delays in receiving laboratory results could affect the flow of
ground water through the treatment processes. The accuracy of
analytical results is important if this information will be used
to make treatment or disposal decisions for radioactively
contaminated water. [B6,p.II-3,§7]
Response:
U.S. EPA concurs with these concerns and every effort will be made
during the design of the ground-water extraction and treatment
system to fully address them.
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9. Concern:
The hazardous waste sites and the LLRW site at US Ecology should
be dealt with together in a comprehensive cleanup plan. [B6,p.I-
7,f2; E2,p.51,15-6]
Response:
In response to the suggestion that the various units be treated as
one large facility, there are reasons why the current approach is
preferable. First, various government agencies have independent
jurisdiction over the various units located at the site. IDNS has
jurisdiction over the radioactive waste site. IEPA 1s responsible
for overseeing the closure activities at the New Site as this
would be part of its authorized program. U.S. EPA has
jurisdiction over the corrective action activities at the
hazardous waste units under the Consent Order. This Order was
entered into between U.S. EPA and US Ecology and is binding upon
them and no other parties. Second, it makes sense to split off
the remedies related to the radioactive site from the hazardous
waste sites as the contamination related to each are different in
nature and should be addressed independently. To a degree, the
ground-water activities set forth here will address contamination
emanating from all of the units at the site.
10. Concern:
Several commenters stated that the chemical and low level
radioactive waste sites should not be considered separately in
terms of public health or proposed cleanup plans. The entire area
should be treated as one problem. [B3,p.l,U5; B7,p.15,^3;
C10,p.l,H4; E2,p.34,H2] However, others believe that the chemical
and radioactive waste sites at Sheffield are distinct facilities
with separate ownership, and should be regulated as such.
[D2,p.9,13]
Response:
Please refer to responses to concerns 1.11, V.9, and VI.1.
VI. HEALTH EFFECTS AND CLEANUP LEVELS
1. Concern:
The Public Health Risk Evaluation did not address risks associated
with ground water contaminated with low level radioactive waste.
[A2,p.2,§3; C3,§4]
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44
Response:
This is a correct statement. The calculated risks to health
presented in the RI report focused on the risks associated with
the multiple chemical contaminants being released to ground water
principally from the Old Site. The radioactive constituents in
the ground water are more restricted in their distribution than
these chemical constituents and are associated solely with
specific portions of the Old Site plume. In addition, the levels
of chemicals contaminants in the overlapping areas of the chemical
and radioactive plumes are lower relative to the more contaminated
areas of the plume. See figures on pages 5-30, 5-31, and 5-32 for
maps showing contoured chemical concentrations in the Old Site
plume. Table 5-7 on page 5-36 of the RI report lists the levels
of radioactive contaminants detected in the ground water in 1988.
Figure 1-10 of the ground-water FS (page 1-48) illustrates
overlapping areas of the two plumes.
Using sampling data supplied in Appendix M of the Remedial
Investigation (RI) report, the estimated lifetime excess cancer
risk from ingesting the ground water containing radionuclides from
the LLRW has been estimated. The sampling data included data for
samples taken from 20 wells in the area affected by the LLRW that
were analyzed for 19 radionuclides (radioactive elements). Of the
19 radionuclides sampled for, eleven were identified at the site.
To be conservative, any radionuclide concentration detected was
assumed to come from the site. (Many radionuclides are found to
occur naturally.)
Two methods were used to estimate the excess cancer risk resulting
from exposure to the radionuclides identified at the site.
Exposure was assumed to result from ingestion of ground water as
drinking water. The first method, using risk factors generated by
the U.S. EPA, estimated an excess cancer risk of 4 x 10"6. This
means that under a recreational use scenario, four (4) excess
cancer cases can be expected out of each 1,000,000 recreational
users.
The second method, using similar calculations, but with
incorporating risk factors generated by the International
Commission on Radiological Protection (ICRP), estimates an excess
cancer risk of 5 x 10 . This means that the excess cancer cases
expected from the previously-discussed exposure will be five (5)
excess cancer cases for every 100,000 recreational users.
The difference in risk estimates between the two methods exists
because the second method allows more of the radionuclides
identified at the site to be considered in the final risk
estimate. The first method (using U.S. EPA risk factors) allows
inclusion of seven (7) of the eleven (11) nuclides identified.
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45
The second method (using ICRP risk factors) allows Inclusion of
all eleven (11).
2. Concern:
One commenter expressed a growing concern that there may be a
cancer cluster near Sheffield, with an increasing "number of
cancers of the nature of those normally associated with
radioactivity." [CIO, p. 1,1(6]
Response:
An investigation into the incidence of cancer in Bureau County,
Illinois, was performed by the Illinois Department of Public
Health (IDPH), Division of Epidemiological Studies. A report on
the results of this investigation, entitled "Incidence of Cancer
in Buda, Mineral, Neponset, and Sheffield in Bureau County,
Illinois," was released in September, 1990. The investigation was
performed under the administration of Dr. Holly L. Howe, Chief of
the Division of Epidemiological Studies.
Data for all cancer incidence in the designated area from 1985 to
1988 were obtained from the Illinois State Cancer Registry (an
incidence of cancer is a newly diagnosed case). These data, the
"observed" incidence of cancer, were compared to data from an
area in the State of similar population and age distribution, the
"expected" incidence of cancer. Statistical tests were then
performed on these data to see if there were any statistically
significant differences between the incidence of cancer for each
population. A statistically significant difference could indicate
that the incidence of cancer in Bureau County is higher than
"normal."
The results for all types of cancer combined were as follows. In
males, 37 cases were observed, with 38 expected. For females, 45
cases were observed, with 40 expected. These differences were not
found to be statistically significant for either sex. Therefore,
with regard to combined cancers, no cancer cluster was identified
in the report. Incidence of site-specific canc°rs was also
compared in the report, with no conclusions being made.
It is possible that with a larger data set, possibly facilitated
by using mortality data, more conclusions could be drawn from the
report. (Mortality data is based on deaths attributable to a
particular cause.) :
3. Concern:
US Ecology questions the assumptions behind the risk assessment
used as a basis for determining ground-water cleanup levels. :
These assumptions result in an overestimate of risk by nearly two
orders of magnitude. The risk assessment uses an exposure
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46
scenario that assumes future residential use of the site, with
residents drinking two (2) liters of ground water per day over a
70-year period. Current U.S. EPA guidance on risk assessment for
Superfund sites suggests that 30 years is a more appropriate time
period to estimate "reasonable maximum exposure." Further, future
residential use of the US Ecology Sheffield sites is highly
unlikely, and alternate exposure scenarios, such as recreational
use of the site, should be considered if the risk assessment
process will be used to derive ground-water cleanup goals.
[Dl,p.2,H5; D2,p.4,12; D2,p.5,ll; D2(Att.l),pp.5-10;
D2(Att.2),pp.2-3,12,14-15,19-21,23]
Response:
As this comment indicates, risk estimates in the Final Remedial
Investigation Report (April 1989) were based on the assumptions of
future residential use of the US Ecology site and a 70-year period
of exposure to the most contaminated ground water. These
assumptions were carried through to the risk assessment summary in
U.S. EPA's May 1990, Proposed Plan.
U.S. EPA has carefully considered this comment in light of the
most recent Agency guidance on conducting risk assessments at
hazardous waste sites (Risk Assessment Guidance for Superfund,
Volume I, Human Health Evaluation Manual, December 1989
[EPA/540/1-89/002]). This guidance states that cleanup actions
"should be based on an estimate of the reasonable maximum exposure
(RME) expected to occur under both current and future land-use
conditions." The guidance further indicates that "an assumption
of future residential use may not be justifiable if the
probability that the site will support residential use in the
future is exceedingly small." For example, "if the site is ...
located in a very rural area with a low population density and
projected low growth, ... a more likely alternate future land
use may be recreational."
U.S. EPA believes that future residential use of the US Ecology
site is highly unlikely. The corrective measures proposed by the
Agency will be designed to effectively contain wastes in place and
long-term management and maintenance of the facility will be
required, including continued extraction and treatment of ground
water. Thus, U.S. EPA agrees that a recreational use exposure
scenario is more appropriate for evaluating future risks at this
site. U.S. EPA has adopted the exposure assumptions suggested in
this comment (ingestion of 2 liters of water per day for 32 days
per year over a 20-year period). The Agency has used these
assumptions to evaluate future risks associated with various
ground-water cleanup goals, as described in the next response.
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47
4. Concern:
US Ecology disagrees with the ground-water remediation goals in
the Nay 1990 Proposed Plan. The company states: (1) that U.S.
EPA's use of RCRA practical quantitation limits (PQLs) to
establish ground-water cleanup levels is excessive and unwarranted
and is not supported by any agency guidance and (2) that PQLs have
no basis in the protection of human health and do not consider
conditions specific to the US Ecology site, such as background
concentrations of chemicals. US Ecology further states that the
ground-water remediation goals proposed in the draft FS for ground
water are acceptable and will protect human health and comply with
all applicable or relevant regulations. However, US Ecology's
comments propose two additional sets of ground-water cleanup
levels, based primarily on Maximum Contaminant Levels (MCLs),
regulatory standards for drinking water. [01,p.2,1(3-4; D2,pp.4-6;
D2,p.8,Hl; D2(Att.l),pp.3-13; D2(Att.2),pp.l-2,6,9-ll,21-23]
Response:
In this Response to Comments, U.S. EPA is proposing a set of
ground-water remediation goals slightly different from the goals
listed in the Proposed Plan. In putting forth these goals, the
Agency has considered: (1) regulatory requirements for ground-
water protection standards in 40 CFR 264; (2) the Proposed Rule
for Corrective Action for Solid Waste Management Units at
Hazardous Waste Management Facilities (55 FR 30798, July 27,
1990); (3) background concentrations for the 11 contaminants that
account for the majority of risk; and (4) the exposure and risk
assessment assumptions described in the previous response.
According to 40 CFR 264.94(a), ground-water protection standards
should be set at background levels of the hazardous constituents
or at the maximum contaminant levels (MCLs) established by U.S.
EPA under the Safe Drinking Water Act. Alternate concentration
limits (ACL) are appropriate only if the use of these limits will
not pose a substantial present or potential hazard to human
health. The Proposed Rule for Corrective Action requires ground-
water cleanup standards that ensure protection of human health,
taking into account the potential uses of ground water.
Background concentrations for all eleven (11) contaminants were
evaluated by reviewing sampling results from well 434, designated
in the RI as the background well for the glacial aquifer. Nine of
the eleven (11) contaminants were not detected in this well;
arsenic and methylene chloride were found in two (2) of eight (8)
samples with maximum concentrations of 7 jig/L and 10 /jg/L,
respectively. Based on these results and on the guidelines listed
above, U.S. EPA has selected ground-water protection standards
that reflect either site-specific background concentrations (based
on routinely achievable analytical detection limits) or MCLs.
These goals are as follows:
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48
10 /jg/L arsenic
5 /ig/L benzene, chloroform, 1,1-
dichloroethane, 1,2-dichloroethane,
1,1-dichloroethene, 1,2-
dichloropropane, methylene chloride,
tetrachloroethene, trlchloroethene
2 ng/L vinyl chloride
Ingestion of ground water with these concentrations, under the
exposure assumptions described in the previous response, will
result in an excess cancer risk of 2 x 10'5. This value is within
the 10"4 to 10"* target range defined as the "protective risk range"
in the Proposed Rule for Corrective Action.
U.S. EPA believes these goals to be reasonable, achievable, and
protective of human health under the assumptions that: (1) ground
water above these concentrations has not and will not migrate
beyond the current facility boundary; and (2) the facility will
remain under active management and post-closure care by US
Ecology. Should either of these conditions change, the cleanup
goals and exposure assumptions on which they are based would be
reevaluated.
5. Concern:
Risk assessment of hazardous waste sites is an uncertain process.
The results of this process must be viewed as estimates, with a
range of possible values, rather than as single value, invariant
results. U.S. EPA has failed to acknowledge that the uncertainty
about the results of risk assessments is generally at least an
order of magnitude. [D2(Att.l),p.5,1fl; D2(Att.2),p.l9,12]
Response:
U.S. EPA recognizes the uncertainty inherent in the risk
assessment of hazardous waste sites and has specifically
considered this uncertainty in proposing ground-water cleanup
goals for the US Ecology site. The estimated risk for ingestion
of ground water containing chemical contamination at the proposed
cleanup levels is approximately 2 x 10"5. This estimate is near
the middle of U.S. EPA's target risk range of KT1 to 10"6. The
Agency believes that these cleanup goals are more appropriate than
less protective goals suggested by US Ecology because of the
uncertainties that must be factored into the risk assessment.
These uncertainties include: (1) the potential synergistic
effects of exposure to multiple chemicals; (2) the additional
risks due to radionuclides in ground water at the site (see
response to concern VI.1 above); and (3) the need to maintain
adequate post-closure care at the facility.
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49
6. Concern:
The Risk Assessment Summary in the proposed plan Indicates that if
ground water were cleaned up to the RCRA Practical Quantitative
Limits proposed, risks from exposure would still be above the
target risk range established by U.S. EPA. [A2,p.2,§4]
Response:
The Proposed Plan estimated the cancer risks for future ground-
water consumption to be slightly higher than 10"* (one (1) case of
cancer for every 10,000 people exposed). The 10"* figure
represents the lower limit of U.S. EPA's target risk range. This
risk estimate was based on the assumptions that: (1) ground water
would contain contamination at the proposed cleanup goals; (2) the
US Ecology site would be used for future residential development;
and (3) persons drinking the ground water would reside in this
development for seventy (70) years.
As indicated in the response to comment VI.3 above, future
residential development of the US Ecology site is extremely
unlikely. Current U.S. EPA guidance on risk assessment suggests
that recreational use of the site is a more plausible scenario for
future exposure to ground water, after cleanup goals proposed in
this document have been achieved. Under these conditions, the
estimated cancer risk of 2 x 10'* would be within U.S. EPA's target
risk range.
7. Concern:
Risks due to arsenic in ground water should be reconsidered for
two reasons: (1) the uncertainty about the carcinogenic potency of
this chemical and (2) the high background levels of arsenic near
the site. US Ecology believes that the carcinogenic effects of
arsenic should not be considered in establishing cleanup levels
for this metal. [02,p.5,13; D2,p.6,12; D2(Att. l),p.!3,1f3-4]
Response:
U.S. EPA strongly disagrees with both portions of this comment.
First, there is little debate about the carcinogenicity of
arsenic. This metal can cause cancer in humans after inhalation
exposure and from ingestion of drinking water. The specific
carcinogenic potency of arsenic via ingestion is currently under
review. However, this is not sufficient justification for
ignoring arsenic in estimating risks or proposing cleanup goals
for ground water at US Ecology. U.S. EPA has used the most
recently available unit risk for arsenic (from the Agency's
Integrated Risk Information System database, June 1990) to
estimate ground-water ingestion risks. This assessment can be
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50
repeated when a new risk factor is available, and the risks and
ground-water cleanup goal adjusted, if necessary.
Second, ground-water sampling data from the RI do not support the
statement that background concentrations of arsenic in ground
water are high. Arsenic was detected in only two of eight samples
from well 434, the glacial aquifer background well for the RI.
The maximum concentration detected was 7 /*g/L. Further, although
most of the waste volume for the Old Site is unknown, the known
portion includes arsenic-containing wastes. Thus, arsenic found
in ground water near the Old Site Is much more likely due to waste
disposal activities than background, and arsenic must be
considered when evaluating site risks and proposing cleanup goals.
VII. MISCELLANEOUS COMMENTS
1. Concern:
Hazardous and toxic wastes buried at the landfill pose a present
and future danger to the environment and to the health and welfare
of the People of the State of Illinois. Every possible step to
protect citizens' health and welfare has not been examined; a
final cleanup plan must promote long-term effectiveness.
[A5,p.l,12; Al,p.l,H4-5; C3,§5; C3,§8; E2,p.l9,H3] :
Response:
U.S. EPA has required US Ecology to conduct the Remedial
Investigation and Feasibility Study (RI/FS) following U.S. EPA
guidance. A document titled "Initial Screening of Remedial
Technologies" was submitted by US Ecology in August 1988. U.S.
EPA required US Ecology to consider further (in the draft FS)
exhumation and other technologies not screened out in the August
1988, document. All viable, practical, proven technologies have
been evaluated. U.S. EPA has selected a remedy which will be
protective of human health by reducing greatly the chances of
future releases through effective source control and by addressing
the previous releases by stopping plume expansion and extracting
and treating contaminated ground water until established ground-
water protection standards specified by U.S. EPA in this document
are achieved. US Ecology will be required to manage the source
control and ground-water remediation components of the corrective
measure so that long-term protection is assured. Should any
additional areas of release be identified around the New Site
which were not apparent during the RI/FS process, further studies
would be conducted and a separate decision made as to how to
address them.
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51
Concern:
One commenter stressed a need for corrective action to begin as
soon as possible. [C4,p.7,f2]
Response:
U.S. EPA concurs with the commenter. Experience with ground-water
remediation at other hazardous waste sites has shown the
importance of early installation and operation of extraction
wells. This is conducive to controlling plume expansion and a
more rapid remediation of the ground water. In addition,
identified releases of hazardous wastes or constituents will
likely continue until source control measures are in place.
However, all components of the corrective measures require further
design phases prior to implementation and some components may
require obtaining a permit before certain procedures can be
performed.
Comment:
As a result of IDNS and U.S. EPA's meeting on December 21, 1989,
to discuss proposed alternatives, U.S. EPA concluded that IDNS
"concurred" with the preferred alternative, specifically, slurry
walls. IDNS feels 'concurrence' is not entirely accurate.
[A3,p.2,14; A4,p.2,H5; E2,p.72,13-5]
Response:
The Proposed Plan (page 36) did not wish to imply total
concurrence with the Plan; rather it qualified the degree to which
IDNS and U.S. EPA agreed on the conceptual approach for
remediation during discussion at that meeting. Specifically,
discussions resulted in the conclusion that, among other things:
(1) Placing slurry walls around the Old Site, rather than
subsurface drains, was expected to ultimately result in fewer
changes to the local hydraulic gradients thus impacting the
existing conditions around the LLRW site to a lesser degree.
Ground-water levels outside the slurry wall can be maintained at a
higher level than inside, whereas drains would be more likely to
cause a more general lowering of the water table. (2) Extracted
ground water, which may contain radioactive constituents, would
require testing for the presence of specified radipnuclides.
Appropriate treatment and management would be required if
detected.
Concern:
There is some concern that the cost of remedying the site will
ultimately fall on the taxpayers. Several commenters stated that
the corporation responsible for problems at the site should bear
the full financial responsibility for cost of corrective action.
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52
[A5, transmittal letter, U2; B3,p.2,J2-4; C3,p.l,§l; C9,p.l,U2;
Cll} E2,p.35,fl]
Response:
US Ecology signed the Consent Order 1n 1985 to conduct an RI/FS
and to Implement the corrective action selected by U.S. EPA. To
date, US Ecology has performed each task required under the
Consent Order at considerable expense to the company (I.e.,
estimated, 1n a US Ecology press release, to be about $4.5 million
so far). US Ecology provided financial assurance $2.50 million),
as required In the Consent Order, to guarantee performance of the
RI/FS and Implementation of the selected corrective action. US
Ecology has absorbed the costs of the RI/FS and has given every
indication that the company intends to comply with the Consent
Order and implement the selected remedy.
5. Concern:
Area citizens should be the final judge of the plan's
effectiveness. [Al,p.2,Kl]
Response:
U.S. EPA policy and guidance promotes public involvement and
comment during the decision-making process. The State of
Illinois, public officials, and private citizens have commented on
the Proposed Plan. The next step, that of selecting the remedy,
is left to U.S. EPA under its statutory mandate. The preferred
alternative from the Proposed Plan can be, and has been, modified
based on comments received during the comment period.
6. Concern:
Commenter says that the cost of the remedy is secondary to
citizenr/ protection. [Al,p.2,\2]
Response:
U.S. EPA has selected corrective measures based on the ability of
the technologies chosen to protect human health and the
environment. Under RCRA, cost is not considered as a factor
except when deciding between alternatives which are determined to
be equally protective.
7. Concern:
Several individuals emphasized the need for some type of
contingency plan to deal with components of the corrective action,
such as slurry walls, caps, and ground-water monitoring, ;
extracting, and treatment. The contingency plan is necessary
because these components are not totally reliable and are not
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53
described in sufficient detail in U.S. EPA's proposed plan. The
contingency plan should describe the required care, maintenance,
and repairs for slurry walls and other components. The plan
should also include provisions to use advances in technology as
these become available. [A5,p.3,^l; 64,^3-6; C4,p.4,\5,p.2,f2,
and p.7,1(2; B6,p.I-7,U3; E2,p.37,^3; E2,p.52,K3]
Response:
U.S. EPA's Proposed Plan selected alternatives from the two draft
FS reports submitted by US Ecology as a conceptual approach to
remediate the site and suggested some modifications to the
alternatives proposed. While it is true that the Proposed Plan
itself does not contain design detail, the individual alternatives
themselves are described in considerable detail in the draft FS
reports and their appendices. It is clear that estimated costs
for construction and for operation and maintenance of specific
components could not have been calculated and presented in these
reports if considerable detail had not been generated. However,
during the CMI, much more detail will be added prior to approval
of a final design. U.S. EPA will require that specific
performance criteria be established for each component of the
corrective measures. In conjunction with the performance
standards, procedures will be established for evaluating each
component's performance and, if the performance is not adequate,
an existing contingency plan will be implemented to address the
problem identified. If a specific technology is shown to not be
effective, the company will be required to implement other
technologies, as approved by U.S. EPA.
8. Concern:
US Ecology points out that the Old Site ceased operation before
the passage of RCRA and should not be referred to as a RCRA site.
[D2,p.l4,Hl]
Response:
The US Ecology site is a RCRA hazardous waste disposal facility.
A RCRA Part A permit application was submitted by US Ecology for
the New Site activities and US Ecology obtained interim status
allowing it to operate at this facility. The New Site was
operated from 1974 into 1983. The Old Site was operated from 1963
to 1974 prior to passage of RCRA in 1976. However, the wastes
disposed of in both disposal sites consist of wastes currently
defined as hazardous under RCRA. The Old Site is most correctly
called a "solid waste management unit" (SWMU) and both sites are
subject to post-closure permit requirements. Releases of
hazardous waste or hazardous waste constituents from a permitted
facility require remediation under the permit. Under interim
status, a corrective action consent order has been used to
implement corrective action activities. In this case, U.S. EPA
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54
and US Ecology entered Into a Consent Order to address corrective
action at this interim status facility.
9. Concern:
One commenter questions the reasons US Ecology purchased 84.5
acres during the period 1985-1987. Did they fear "off-site
migration of plume?" [Bl,p.4H3]
Response:
US Ecology has purchased property at various times for at least
three different reasons: (1) For remedial investigation studies,
including placement of RI monitoring wells (see purchased blocks
of property labeled numbers "7" and "10" on Figure 2-2, page 2-6
of the RI report); (2) For creation of a "buffer zone" required
under a Consent Order with IDNS (see blocks of property labeled
numbers "5," "6," "8," and "9"); and (3) For use as "borrow
areas," including clay for the LLRW site cap (see property labeled
number "4").
10. Concern:
U.S. EPA's Proposed Plan does not include detailed design and
construction information. When a complete remediation plan is
developed at a later date, the public should be allowed to comment
on this document. [B6,p.II-l,H2]
Response:
No statutory authority requires U.S. EPA to solicit public
participation or comment on the various stages of design under the
CMI (i.e., preliminary, intermediate, prefinal, and final) and no
guidance or framework has been developed for incorporating public
comments or such documents which, by their nature, are draft until
approved. However, U.S. EPA will continue to update citizens and
send documents to the repository for review as they become
available.
11. Concern:
U.S. Ecology is concerned about lEPA's role in overseeing
corrective action at the Sheffield sites and that IEPA will impose
unnecessarily stringent and unrealistic requirements in this role.
Response:
IEPA has authority to review closure activities at hazardous waste
facilities because Illinois has been authorized to carry out these
activities in lieu of U.S. EPA in the State of Illinois. U.S. EPA
believes that IEPA has responsibility and authority to review
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closure activities at the New Site. It is U.S. EPA's
understanding that IEPA and US Ecology jointly waived the 90-day
review requirement for closure/post-closure plans In 1985. Thus,
IEPA will continue to be involved in closure activities for the
New Site.
The US Ecology landfills are also subject to a post-closure permit
to be issued by IEPA. As of this year (April 1990), IEPA has been
authorized to include the corrective action portions of post-
closure permits in the permits it Issues as an authorized State.
12. Concern:
US Ecology believes that U.S. EPA should take full RCRA
jurisdiction over the US Ecology Sheffield sites and that the
Agency should declare that corrective action implemented pursuant
to the §3008(h) order is equivalent to final closure of the
facility. [D2,p.12,^3]
Response:
It has also been suggested that the Old and New Site should be
treated as a corrective action management unit. The basis for
this suggestion is the proposed corrective action rule issued on
July 20, 1990, at 55 Federal Register 30798. Under this proposal,
the Agency has the authority to designate corrective action
management units (CAMU) which may contain more than one unit in a
contaminated area under certain circumstances. The Agency does
not feel it is appropriate to designate these units as a CAMU at
the current time. First, the Agency under the proposed
regulations has discretion to designate units as CAMUs based on
site-specific circumstances. In this case, the old and new units
are sufficiently independent of each other such that the Agency
feels that they should not be designated as a CAMU. Second, to
date, the proposed regulations have not been finalized; and
therefore, the process for designating units as CAMUs is not in
force at this point. As far as lEPA's jurisdiction over this
facility, Illinois is an authorized State for portions of the RCRA
program.
RESPONSE TO PUBLIC CONCERN
All of the significant concerns raised by the public were answered as
described above. Although the major components of the selected corrective
measures are the same as those proposed in the Proposed Plan, several
significant details and requirements were amended based on comments received.
1. Several new monitoring wells will be added around the New Site to
facilitate detection of any future or presently undetected releases-to
ground water.
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2. Revised ground-water protection standards are included.
3. Ground-water modeling will be required to predict the effect of these
corrective measures, once implemented, on the LLRW site.
4. Contingency plans will be developed to negate any potentially adverse
effects on the LLRW site which may result during or after implementation
of the corrective measures.
5. Performance standards will be required and established for each
component of the corrective measures. This will allow for evaluation of
the component's effectiveness.
REMAINING CONCERNS
One remaining concern is the request from at least one group of
commenters that they be allowed to review and comment on the CMI design
details as they are developed prior to implementation of the selected
corrective measures. At this time, no mechanism exists to grant this request.
Certainly, the community will be provided with updates on the project during
the CMI process through citizen letters and documents sent to the repository
in Sheffield, Illinois.
y
DECLARATIONS
It has been determined that the selected remedy being implemented is
appropriate and will be protective of human health and the environment.
Date
Valdas V. Adaml
Regional Admin/strator
U.S. Environmental Protection Agency
Region 5 '
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ATTACHMENT I
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CORRECTIVE MEASURE IMPLEMENTATION
AT
US ECOLOGY. INC.. SHEFFIELD. ILLINOIS
The purpose of this Corrective Measure Implementation (CMI) program is to
design, construct, operate, maintain, and monitor the performance of the
corrective measure or measures selected to protect human health and the
environment. Respondent will furnish all personnel, materials and services
necessary for the implementation of the corrective measure or measures.
I. Corrective Measure Implementation Program Plan
The Respondent shall prepare a Corrective Measure Implementation
Program Plan. This program will include the development and
implementation of several plans, which require concurrent preparation.
It may be necessary to revise plans as the work is performed to focus
efforts on a particular problem. The Program Plan includes the
following:
A. Program Management Plan
The Respondent shall prepare a Program Management Plan which will
document the overall management strategy for performing the
design, construction, operation, maintenance and monitoring of
corrective measure(s). The plan shall document the responsibility
and authority of all organizations and key personnel involved with
the implementation. The Program Management Plan will also include
a description of qualifications of key personnel directing the
Corrective Measure Implementation Program, including contractor
personnel.
B. Community Relations Plan
Respondent shall propose a Community Relations Plan, or revise an
existing one, to include any changes in the level of concern of
information needs to the community during design and construction
activities.
1. Specific activities which must be conducted during the design
stage are the following:
a. Revise the facility Community Relations Plan to reflect
knowledge of citizen concerns and involvement at this
stage of the process; and
b. Prepare and distribute a public notice and an updated
fact sheet at the completion of engineering design.
2. Specific activities to be conducted during the construction
stage could be the following: Depending on citizen interest
at a facility at this point in the corrective action process,
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community relations activities could range from group meetings
to fact sheets on the technical status.
C. Data Collection Quality Assurance Plan
The Respondent shall prepare a plan to document all monitoring
procedures: sampling, field measurements and sample analysis
performed during the design, construction, and operation phases of
the corrective measures implementation and the long-term
monitoring of the performance of the measures. The plan shall be
designed to ensure that all information, data and resulting
decisions are technically sound, statistically valid, and properly
documented.
1. Data Collection Strategy
The strategy section of the Data Collection Quality Assurance
Plan shall include, but not be limited to the following:
a. Description of the intended uses for the data, and the
necessary level of precision and accuracy for these
intended uses;
b. Description of methods and procedures to be used to assess
the precision, accuracy and completeness of the
measurement data;
c. Description of the rational used to assure that the data
accurately and precisely represent a characteristic of a
population, parameter variations at a sampling point, a
process condition or an environmental condition. Examples
of factors which shall be considered and discussed
include:
i. Environmental conditions at the time of sampling;
ii. Number of sampling points;
iii. Representativeness of selected media; and
iv. Representativeness of selected analytical
parameters.
Description of the measures to be taken to assure that the
following data sets can be compared to each other:
i. RFI data generated by the Respondent over some time
period;
ii. RFI data generated by an outside laboratory or
consultant versus data generated by Respondent;
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iii. Data generated by separate consultants or
laboratories; and
iv. Data generated by an outside consultant or
laboratory over some time period; and
e. Details relating to the schedule of, and information to be
provided in quality assurance reports. The reports should
include but not be limited to:
i. Periodic assessment of measurement data accuracy,
precision, and completeness;
ii. Results of performance audits;
iii. Results of system audits;
iv. Significant quality assurance problems and
recommended solutions; and
v. Resolutions of previously stated problems.
Sampling
The Sampling section of the Data Collection Quality Assurance
Plan shall discuss:
a. Selecting appropriate sampling locations, depths, etc.;
b. Providing a statistically sufficient number of sampling
sites;
c. Measuring all necessary ancillary data;
d. Determining conditions under which sampling should be
conducted;
e. Determining which media are to be sampled (e.g., ground
water, air, soil, sediment, etc.);
f. Determining which parameters are to be measured and where;
g. Selecting the frequency of sampling and length of sampling
period;
h. Selecting the types of samples (e.g., composites vs.
grabs) and number of samples to be collected;
i. Measures to be taken to prevent contamination of the
sampling equipment and cross contamination between
sampling points;
j. Documenting field sampling operations and procedures,
including:
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i. Documentation of procedures for preparation of
reagents or supplies which become an integral part
of the sample (e.g.,filters, and adsorbing
reagents);
ii. Procedures and forms for recording the exact
location and specific considerations associated with
sample acquisition;
iii. Documentation of specific sample preservation
methods;
iv. Calibration of field devices;
v. Collection of replicate samples;
vi. Submission of field-biased blanks, where
appropriate;
vii. Potential interferences present at the facility;
viii. Construction materials and techniques, associated
with monitoring wells and piezometers;
ix. Field equipment and sample containers listing;
x. Sampling order; and
xi. Decontamination procedures;
k. Selecting appropriate sample containers;
1. Sample preservation; and
m. Chain-of-custody, including:
i. Standardized field tracking reporting forms to
establish sample custody in the field prior to
shipment and during shipment; and
ii. Pre-prepared sample labels containing all
informationnecessary for effective sample tracking.
3. Field Measurements
The Field Measurements section of the Data Collection Quality
Assurance Plan shall discuss:
a. Selecting appropriate field measurement locations, depths,
etc.;
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b. Providing a statistically sufficient number of field
measurements;
c. Measuring all necessary ancillary data;
d. Determining conditions under which field measurement
should be conducted;
e. Determining which media are to be addressed by appropriate
field measurements (e.g., ground water, air, soil,
sediment, etc.);
f. Determining which parameters are to be measured and where;
g. Selecting the frequency of field measurement and length of
the field measurements period; and
h. Documenting field measurement operations and procedures,
including:
i. Procedures and forms for recording raw data and the
exact location, time, and facility-specific
considerations associated with the data acquisition;
ii. Calibration of field devices;
iii. Collection of replicate measurements;
iv. Submission of field-biased blanks, where
appropriate;
v. Potential interference present at the facility;
vi. Construction material and techniques associated with
monitoring wells and piezometers used to collect
field data;
vii. Field equipment listing;
viii. Order in which field measurements were made; and
ix. Decontamination procedures.
Sample Analysis
The Sample Analysis section of the Data Collection Quality
Assurance Plan shall specify the following:
a. Chain-of-custody procedures, including:
i. Identification of a responsible party to act as
sample custodian at the laboratory, who is
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authorized to sign for incoming field samples,
obtain documents of shipment, and verify the data
entered onto the sample custody records;
ii. Provision for a laboratory sample custody log
consisting of serially numbered standard lab-
tracking report sheets; and
iii. Specification of laboratory sample custody
procedures for sample handling, storage, and
dispersion for analysis;
b. Sample storage procedures and storage times;
c. Sample preparation methods;
d. Analytical procedures, including:
i. Scope and application of the procedure;
ii. Sample matrix;
iii. Potential interferences;
iv. Precision and accuracy of the methodology; and
v. Method detection limits;
e. Calibration procedures and frequency;
f. Data reduction, validation and reporting;
g. Internal quality control checks, laboratory performance
and system audits and frequency, including:
i. Method blanks;
ii. Laboratory control samples;
iii. Calibration check samples;
iv. Replicate samples;
v. Matrix-spiked samples;
vi. "Blind" quality control samples;
vii. Control charts;
viii. Surrogate samples;
ix. Zero and span gases; and
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8
x. Reagent quality control checks;
h. Preventative maintenance procedures and schedules;
i. Corrective action (for laboratory problems); and
j. Turnaround time.
D. Data Management Plan
The Respondent shall develop and initiate a Data Management Plan
to document and track investigation data and results. This plan
shall identify and set up data documentation materials and
procedures, project file requirements, and project-related
progress reporting procedures and documents. The plan shall also
provide the format to be used to present the raw data and
conclusions of the data collected (e.g., ground-water elevations,
hydraulic conductivities, permeabilities, analytical data,
particle-size analysis, etc.).
1. Data Record
The data record shall include the following:
a. Unique sample or field measurement code;
b. Sampling or field measurement location and sample or
measurement type;
c. Sampling or field measurement raw data;
d. Laboratory analysis identification number;
e. Property or component measured; and
f. Result of analysis (e.g., concentration).
2. Tabular Displays
The following data shall be presented in tabular displays:
a. Unsorted (raw) data;
b. Results for each medium, or for each constituent
monitored;
c. Data reduction for statistical analysis;
d. Sorting of data by potential stratification factors (e.g.,
location, soil layer, topography); and
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e. Summary data.
3. Graphical Displays
The following data shall be presented in graphical formats
(e.g., bar graphs, line graphs, area or plan maps, isopleth
plots, cross-sectional plots or transacts, three dimensional
graphs, etc.):
a. Display sampling location and sampling grid;
b. Indicate boundaries of sampling area,and areas where more
data are required;
c. Displays levels of contamination at each sampling
location;
d. Display geographical extent of contamination;
e. Display contamination levels, averages, and maxima;
f. Illustrate changes in concentration in relation to
distance from the source, time, depth or other parameters;
and
g. Indicate features affecting intramedia transport and show
potential receptors.
II. Corrective Measure Design
Respondent shall prepare final construction plans and specifications
to implement the corrective measure(s) at the facility as defined in
the Corrective Measure Study.
A. Design Plans and Specifications
Respondent shall develop clear and comprehensive design plans and
specifications which include, but are not limited to the
following:
1. Discussion of the design strategy and the design basis,
including:
a. Compliance with all applicable or relevant
environmental and public health standards; and
b. Minimization of environmental and public impacts.
2. Discussion of the technical factors of importance including:
a. Use of currently accepted environmental control measures
and technology;
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10
b. The constructability of the design; and
c. Use of currently acceptable construction practices and
techniques.
3. Description of assumptions made and detailed justification of
these assumptions;
4. Discussion of the possible sources of error and references to
possible operation and maintenance problems;
5. Detailed drawings of the proposed design including:
a. Qualitative flow sheets; and
b. Quantitative flow sheets.
6. Tables listing equipment and specifications;
7. Tables giving material and energy balances;
8. Appendices including:
a. Sample calculations (one example presented and explained
clearly for significant or unique design calculations);
b. Derivation of equations essential to understanding the
reports; and
c. Results of laboratory or field tests.
9. Detailed performance standards for each component of the
corrective measures and development of procedures to evaluate
performance and also contingency plans to address inadequate
performance.
B. Operation and Maintenance Plan
Respondent shall prepare an Operation and Maintenance Plan to
cover both implementation and long-term maintenance of the
corrective measure components. The plan shall be composed of the
following elements:
1. Description of normal operation and maintenance (O&M):
a. Description of tasks for operation;
b. Description of tasks for maintenance;
c. Description of prescribed treatment or operation
conditions; and
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11
d. Schedule showing frequency of each O&M task;
Description of potential operating problems:
a. Description and analysis of potential operation problems;
b. Sources of information regarding problems; and
c. Common and/or anticipated remedies;
Description of routine monitoring and laboratory testing:
a. Description of monitoring tasks;
b. Description of required laboratory tests and their
interpretation;
c. Required QA/QC; and
d. Schedule of monitoring frequency and date, if
appropriate, when monitoring may cease;
Description of alternate O&M:
a. Should systems fail, alternate procedures to prevent
undue hazard; and
b. Analysis of vulnerability and additional resource
requirements should a failure occur;
Safety plan:
a. Description of precautions, of necessary equipment, etc.,
for site personnel; and
b. Safety tasks required in event of systems failure;
Description of equipment:
a. Equipment identification;
b. Installation of monitoring components;
c. Maintenance of site equipment; and
d. Replacement schedule for equipment and installed
components; and
Records and reporting mechanisms required:
a. Daily operating logs;
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12
b. Laboratory records;
c. Records for operating costs;
d. Mechanism for reporting emergencies;
e. Personnel and maintenance records; and
f. Monthly/annual reports to the Illinois Environmental
Protection Agency.
An initial Draft Operation and Maintenance Plan shall be submitted
simultaneously with the Prefinal Design Document submission and
the Final Operation and Maintenance Plan with the Final Design
Documents.
C. Cost Estimate
Respondent shall develop cost estimates for the purpose of
assuring that the facility has the financial resources necessary
to construct and implement the corrective measure. The cost
estimate developed in the Corrective Measure Study shall be
refined to reflect the more detailed/accurate design plans and
specifications being developed. The cost estimate shall include
both capital and operation and maintenance costs.
D. Project Schedule
Respondent shall develop a Project Schedule for construction and
implementation of the corrective measure or measures which
identifies timing for initiation and completion of all critical
path tasks. Respondent shall specifically identify dates for
completion of the project and major interim milestones. An
Initial Project Schedule shall be submitted simultaneously with
the Prefinal Design Document submission and the Final Project
Schedule with the Final Design Document.
E. Construction Quality Assurance Objectives
Respondent shall identify and document the objectives and
framework for the development of a construction quality assurance
program including, but not limited to the following:
responsibility and authority; personnel qualifications; inspection
activities, sampling requirements; and documentation.
F. Health and Safety Plan
Respondent shall prepare a facility Health and Safety Plan to
address the activities to be performed at the facility to
implement the corrective measures.
1. Major elements of the Health and Safety Plan shall include:
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13
a. Facility description including availability of resources
such as roads, water supply, electricity and telephone
service;
b. Describe the known hazards and evaluate the risks
associated with the incident and with each activity
conducted;
c. List key personnel and alternates responsible for site
safety, response operations, and for protection of public
health;
d. Delineate work area;
e. Describe levels of protection to be worn by personnel in
work area;
f. Establish procedures to control site access;
g. Describe decontamination procedures for personnel and
equipment;
h. Establish site emergency procedures;
i. Address emergency medical care for injuries and
toxicological problems;
j. Describe requirements for an environmental surveillance
program;
k. Specify any routine and special training required for
responders; and
1. Establish procedures for protecting workers from weather-
related problems.
The Facility Health and Safety Plan shall be consistent with:
a. NIOSH Occupational Safety and Health Guidance Manual for
Hazardous Waste Site Activities (1985);
b. U.S. EPA Order 1440.1 - Respiratory Protection;
c. U.S. EPA Order 1440.3 - Health and Safety Requirements
for Employees engaged in Field Activities;
d. Facility Contingency Plan;
e. U.S. EPA Standard Operating Safety Guide (1984);
f. OSHA regulations particularly in 29 CFR 1910 and 1926;
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g. State and local regulations; and
h. Other U.S. EPA guidance as provided.
G. Design Phases
The design of the corrective measures should include the phases
outlined below.
1. Preliminary design
The Respondent shall submit the preliminary design when the
design effort is approximately 30% complete. At this stage
the Respondent shall have field verified the existing
conditions of the facility. The preliminary design shall
reflect a level of effort such that the technical
requirements of the project have been addressed and outlined
so that they may be reviewed to determine if the final design
will provide an operable and usable corrective measure.
Supporting data and documentation shall be provided with the
design documents defining the functional aspects of the
program. The preliminary construction drawings by Respondent
shall reflect organization and clarity. The scope of the
technical specifications shall be outlined in a manner
reflecting the final specifications. The Respondent shall
include with the preliminary submission design calculations
reflecting the same percentage of completion as the design
they support.
2. Intermediate design
Complex project design may necessitate review of the design
documents between the preliminary and the prefinal/final
design. At the discretion of the Agency, a design review may
be required at 60% completion of the project. The
intermediate design submittal should include the same
elements as the prefinal design.
3. Correlating plans and specifications
General correlation between drawings and technical
specifications is a basic requirement of any set of working
construction plans and specifications. Before submitting the
project specifications the Respondent shall:
a. Coordinate and cross-check the specifications and
drawings; and
b. Complete the proofing of the edited specifications and
required cross-checking of all drawings and
specifications.
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These activities shall be completed prior to the 95% prefinal
submittal to the Agency.
4. Equipment start-up and operator training
The Respondent shall prepare, and include in the technical
specifications governing treatment systems, contractor
requirements for providing: appropriate service visits by
experienced personnel to supervise the installation,
adjustment, start-up and operation of the treatment systems,
and training covering appropriate operational procedures once
the start-up has been successfully accomplished.
5. Additional studies
Corrective Measure Implementation may require additional
studies to supplement the available technical data. At the
direction of the Agency for any such studies required, the
Respondent shall furnish all services, including field work
as required, materials, supplies, plant, labor, equipment,
investigations, studies and superintendence. Sufficient
sampling, testing an analysis shall be performed to optimize
the required treatment and/or disposal operations and
systems. There shall be an initial meeting of all principal
personnel involved in the development of the program. The
purpose will be to discuss objectives, resources,
communication channels, role of personnel involved and
orientation of the site, etc. The interim report shall
present the results of the testing with the recommended
treatment or disposal system (including options). A review
conference shall be scheduled after the interim report has
been reviewed by all interested parties. The final report of
the testing shall include all data taken during the testing
and a summary of the results of the studies.
6. Prefinal and final design
The Respondent shall submit the prefinal/final design
documents in two parts. The first submission shall be at 95%
completion of design (i.e., prefinal). After approval of the
prefinal submission, the Respondent shall execute the
required revisions and submit the final documents 100%
complete with reproducible drawings and specifications.
The prefinal design submittal shall consist of the Design
Plans and Specifications, Operation and Maintenance Plan,
Capital and Operating and Maintenance Cost Estimate, Project
Schedule, Quality Assurance Plan and Specifications for the
Health and Safety Plan.
The final design submittal shall consist of the Final Design
Plans and Specifications (100% complete), the Respondent's
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16
Final Construction Cost Estimate, the Final Operation and
Maintenance Plan, Final Quality Assurance Plan, Final Project
Schedule and Final Health and Safety Plan specifications.
The quality of the design documents should be such that the
Respondent would be able to include them in a bid package and
invite contractors to submit bids for the construction
project.
III. Corrective Measure Construction
Following U.S. EPA approval of the final design, the Respondent shall
develop and implement a construction quality assurance (CQA) program
to ensure, with a reasonable degree of certainty, that a completed
corrective measure(s) meets or exceeds all design criteria, plans and
specifications. The CQA plan is a facility specific document which
must be submitted to U.S. EPA for approval prior to the start of
construction. At a minimum, the CQA plan should include the
elements, which are summarized below. Upon U.S. EPA approval of the
CQA plan the Respondent shall construct and implement the corrective
measures in accordance with the approved design, schedule and the CQA
plan. Respondent shall also implement the elements of the approved
Operation and Maintenance plan.
A. Responsibility and Authority
The responsibility and authority of all organizations (i.e.,
technical consultants, construction firms, etc.) and key
personnel involved in the construction of the corrective measure
shall be described fully in the CQA plan. Respondent must
identify a CQA officer and the necessary supporting inspection
staff.
B. Construction Quality Assurance Personnel Qualifications
The qualifications of the CQA officer and supporting inspection
personnel shall be presented in the CQA plan to demonstrate that
they possess the training and experience necessary to fulfill
their identified responsibilities.
C. Inspection Activities
The observations and tests that will be used to monitor the
construction and/or installation of the components of the
corrective measure(s) shall be summarized in the CQA plan. The
plan shall include the scope and frequency of each type of
inspection. Inspections shall verify compliance with all
environmental requirements and include, but not be limited to
air quality and emissions monitoring records, waste disposal
records (e.g., RCRA transportation manifests), etc. The
inspection should also ensure compliance with all health and
safety procedures. In addition to oversight inspections,
Respondent shall conduct the following activities:
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1. Reconstruction inspection and meeting
Respondent shall conduct a preconstruction inspection and
meeting to:
a. Review methods for documenting and reporting inspection
data;
b. Review methods for distributing and storing documents
and reports;
c. Review work area security and safety protocol;
d. Discuss any appropriate modifications of the
construction quality assurance plan to ensure that
site-specific considerations are addressed; and
e. Conduct a site walk-around to verify that the design
criteria, plans, and specifications are understood and
to review material and equipment storage locations.
The preconstruction inspection and meeting shall be
documented by a designated person and minutes should be
transmitted to all parties.
2. Prefinal inspection
Upon preliminary project completion Respondent shall notify
U.S. EPA for the purposes of conducting an prefinal
inspection. The prefinal inspection will consist of a
walk-through inspection of the entire project site. The
inspection is to determine whether the project is complete
and consistent with the contract documents and the U.S. EPA
approved corrective measure. Any outstanding construction
items discovered during the inspection will be identified
and noted. Additionally, treatment equipment will be
operationally tested by the Respondent.
Respondent will certify that the equipment has performed to
meet the purpose and intent of the specifications.
Retesting will be completed where deficiencies are revealed.
The prefinal inspection report should outline the
outstanding construction items, actions required to resolve
items, completion date for these items, and date for final
inspection.
3. Final inspection
Upon completion of any outstanding construction items,
Respondent shall notify U.S. EPA for the purposes of
conducting a final inspection. The final inspection will
consist of a walk-through inspection of the project site.
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The prefinal Inspection report will be used as a checklist
with the final inspection focusing on the outstanding
construction items identified in the prefinal inspection.
Confirmation shall be made that outstanding items have been
resolved.
D. Sampling Requirements
The sampling activities, sample size, sample locations,
frequency of testing, acceptance and rejection criteria, and
plans for correcting problems as addressed in the project
specifications should be presented in the CQA plan.
E. Documentation
Reporting requirements for CQA activities shall be described in
detail the CQA plan. This should include such items as daily
summary reports, inspection data sheets, problem identification
and corrective measures reports, design acceptance reports, and
final documentation. Provisions for the final storage of all
records also should be presented in the CQA plan.
IV. Reports
Respondent shall prepare plans, specifications, and reports as set
forth in Tasks I through IV of this attachment to document the
design, construction, operation, maintenance, and monitoring of the
corrective measure. The documentation shall include, but not be
limited to the following:
A. Progress
Respondent shall at a minimum provide the U.S. EPA with signed,
bimonthly progress reports during the design and construction
phases and quarterly progress reports for operation and
maintenance activities containing:
1. A description and estimate of the percentage of the CMI
completed;
2. Summaries of all findings;
3. Summaries of all changes made in the CMI during the reporting
period;
4. Summaries of all contacts with representative of the local
community, public interest groups or State government during
the reporting period;
5. Summaries of all problems or potential problems encountered
during the reporting period;
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6. Actions being taken to rectify problems;
7. Changes in personnel during the reporting period;
8. Projected work for the next reporting period; and
9. Copies of daily reports, inspection reports,
laboratory/monitoring data, etc.
B. Draft
Respondent shall submit a draft Corrective Measure
Implementation Program Plan, etc. as outlined in Task I of
this attachment;
Respondent shall submit draft Construction Plans and
Specifications, Design Reports, Cost Estimates, Schedules,
Operation and Maintenance plans, and Study Reports as
outlined in Task II of this attachment;
Respondent shall submit a draft Construction Quality
Assurance Program Plan and Documentation as outlined in Task
III of this attachment; and
At the "completion" of the construction of the project, the
Respondent shall submit a Corrective Measure Implementation
Report to U.S. EPA. The Report shall document that the
project is consistent with the design specifications, and
that the corrective measure is performing adequately. The
Report shall include, but not be limited to the following
elements:
a. Synopsis of the corrective measure and certification of
the design and construction;
b. Explanation of any modifications to the plans and why
these were necessary for the project;
c. Listing of the criteria established before the corrective
measure was initiated, for judging the functioning of the
corrective measure and also explaining any modification
to these criteria;
d. Results of facility monitoring, indicating that the
corrective measure will meet or exceed the performance
criteria; and
e. Explanation of the operation and maintenance (including
monitoring) to be undertaken at the facility.
This report should include inspection summary reports,
inspection data sheets, problem identification and corrective
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measure reports, block valuation reports, photographic
reporting data sheets, design engineers' acceptance reports,
deviations from design and material specifications (with
justifying documentation) and as-built drawings.
C. Final
Respondent shall finalize the Corrective Measure Implementation
Program Plan, Construction Plans and Specifications, Design
Reports, Cost Estimates, Project Schedule, Operation and
Maintenance Plan, Study Reports, Construction Quality Assurance
Program Plan/Documentation and the Corrective Measure
Implementation Report incorporating comments received on draft
submissions.
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Facility Submission Summary
A summary of the information reporting requirements contained in the
Corrective Measures Implementation Scope of Work is presented below.
Facility Submission
Due Date
Draft Program Plan Community Relations
Plan and Data Collection and Data
Management Plans (Task I)
Final Program Plan Community Relations
Plan, and Data Collection and Data
Management Plant (Task I)
Design Phases
(Task II A)
- Preliminary Design (30% completion)
- Intermediate Design (60% completion)
- Prefinal Design (95% completion)
- Final Design (100% completion)
(Task II B through G)
- Draft Submittals
- Final Submittals
Additional Studies:
(Task II F)
Additional Studies:
(Task II F)
Interim Report
Final Report
Draft Construction Quality Assurance
Plan (Task III)
Final Construction Quality Assurance
Plan (Task III)
45 days after submittal
of the final CMS report
30 days after receipt of
U.S. EPA comments on these
Draft Plans
30 days after submittal of
Final Program Plan
60 days after approval of
Preliminary Design
90 day after approval of
Intermediate Design
14 days after approval of
Prefinal Design
Concurrent with Prefinal
Design
Concurrent with Final
Design
(Due date established prior to
Final Design)
30 days after receipt of
U.S. EPA comments on Interim
Report
Prior to construction
30 days after U.S. EPA
comments on Construction
Quality Assurance Plan
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