United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R05-92/196
April 1992
&EPA
Superfund
Record of Decision:
MIDCO I (Amendment), IN
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NOTICE
The appendices listed in the index that are not found in this document have been removed at the request of
the issuing agency. They contain material which supplement, but adds no further applicable information to
the content of the document All supplemental material is, however, contained in the administrative record
for this site.
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R05-92/196
3. Recipient^ Accewion No.
4. True end Subtitle
SUPERFUND RECORD OF DECISION
MIDCO I (Amendment), IN
First Remedial Action - Amendment
5. Report Date
04/13/92
7. Author(>)
8. Performing Organization Rept No.
9. Performing Organization Mann and Address
10. Projecl/Tuk/WorkUn!tNo.
11. Contnct(C)orGram(G)No.
(C)
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type ol Report & Period Covered
800/000
14.
15. Supplementary Hole*
PB93-96A130
16. Abstract (UmM: 200 words)
The 4-acre Midco I site is an abandoned, industrial waste recycling, storage, and
disposal facility in Gary, Indiana. The surrounding land use is mixed industrial,
commercial, and residential. The nearest residential area is about 1/4-mile west of
the site. The Calumet Aquifer underlies the site and provides drinking water to wells
within 1 mile of the site. From 1973 to 1979, two different owners operated the
facility and stockpiled thousands of drums of bulk liquid and chemical waste. In 1976,
a fire at the site destroyed an estimated 14,000 waste drums. In 1981, EPA installed a
fence around the site. In 1982, EPA removed all surface wastes, including thousands of
drums and an underground storage tank; excavated and disposed of contaminated surface
soil; and placed a clay cover over much of the site. This ROD amends a 1989 ROD that
addressed the remaining contaminated soil and ground water by treatment of an estimated
12,400 cubic yards of soil using soil vapor extraction and solidification/
stabilization, followed by onsite disposal; excavation and solidification/stabilization
of an estimated 1,200 cubic yards of contaminated sediments, followed by onsite
disposal; and covering the site in accordance with RCRA landfill closure requirements;
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - MIDCO I (Amendment) , IN
First Remedial Action - Amendment
Contaminated Media: soil, sediment, gw
Key Contaminants: VOCs (TCE, toluene, xylenes), metals (chromium, lead), inorganics
b. IdentHiers/Open-Ended Terms
c. COSATI Reid/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Psge)
None
21. No. of Pages
72
22. Price
(SseANSI.Z3t.18)
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R05-92/196
MIDCO I (Amendment), IN
First Remedial Action - Amendment
Abstract (Continued)
ground water pumping and injection into a shallow or deep aquifer. The amended remedy
reduces the estimated amount of soil to be treated, as a result of new information on
arsenic data and amended soil CALs; further defines the site cover requirements; and
further defines the requirements of deep well injection of contaminated ground water.
The primary contaminants of concern affecting the subsurface soil, sediment, and ground
water are VOCs, including TCE, toluene, and xylenes; metals, including chromium and lead;
and inorganics.
The amended remedial action for this ROD includes a reduction in the amount of soil to be
treated to a minimum of 5,200 cubic yards because of the amendment to soil CALs and the
determination that arsenic may not be present above background levels at the site;
treating the contaminated soil onsite using with soil vapor extraction, followed by
in-situ solidification/stabilization; excavating and treating contaminated sediment from
the surrounding wetlands onsite using solidification/stabilization; pumping and treatment
of contaminated ground water using air stripping and carbon absorption, followed by
onsite deep well injection; constructing a final RCRA cover over the entire site;
implementing institutional controls including deed restrictions, and site access
restrictions; conducting long-term monitoring and providing for a contingency remedy in
the event that ground water clean-up action levels for the Calumet Aquifer are
technically impracticable to attain, which includes low-level pumping to contain
contaminated ground water and additional institutional controls. The ground water
treatment or underground injection portions of this remedy may be combined with remedial
actions for the nearby Midco II site. The estimated present worth cost for this amended
remedial action is $10,000,000, which includes an annual O&M cost of $460,000.
PERFORMANCE STANDARDS OR GOALS:
Ground water clean-up standards for the Calumet Aquifer are not changed from the 1989
ROD. Treatment requirements prior to DWI are further defined compared to the 1989 ROD
and include, at a minimum, treatment to MACs, which are required for RCRA delisting.
Specific MACs include methylene chloride 31.5 ug/1; trichloroethene 31.5 ug/1; toluene
6,300 ug/1; chromium 630 ug/1; nickel 630 ug/1; and lead 950 ug/1. Treatment below MACs
will be required, if necessary, to protect underground sources of drinking water. Soil
treatment action levels are increased from IxlO"6 and HI=1 in the 1989 ROD to
5xlO"4and HI=5 in this amendment.
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DECLARATION FOR RECORD OF DECISION AMENDMENT
SITE NAME AND LOCATION
Midco I
Gary, Indiana
STATEMENT OF BASIS AND PURPOSE
This decision document presents a description of an amendment to
the selected remedial action for Midco I developed in accordance
with the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA), as amended by the Superfund Amendments
and Reauthorization Act of 1986 (SARA), and to the extent
possible the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP). This decision document amends the Record
of Decision dated June 30, 1989.
This decision is based on the contents of the administrative
record for the Midco I site. The attached index identifies the.
items which comprise the administrative record for this Record of
Decision Amendment.
The State of Indiana concurs in this amendment to the remedy
selection by U.S. EPA for the Midco I site.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing, the response action
selected in the Record of Decision (ROD) Amendment, may present
an imminent and substantial endangerment to public health,
welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDY (AS AMENDED)
The primary reasons for amending the selected remedy at Midco I
relate -to: 1) a change in the method for determining how much
soil will be treated; 2) further definition of the degree of
treatment of contaminated ground water that EPA will require
prior to deep well injection including a proposal to delist the
extracted ground water (the ground water contains listed
hazardous wastes as defined in the Resource Conservation and
Recovery Act) through this Record of Decision Amendment provided
that the extracted ground water is treated to meet specified
maximum allowable concentrations (MACs) prior to disposing of the
extracted ground water by deep well injection.
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The selected remedial action includes:
On-site treatment of a minimum of approximately 5,200 cubic
yards of contaminated soil and waste material, and possibly
more dependent upon the results of further sampling, by soil
vapor extraction and in-situ solidification/stabilization.
Excavation and on-site solidification/stabilization of
contaminated sediments from the surrounding wetlands.
Installation and operation of a ground water pumping system
to intercept contaminated ground water from the site.
Contingency measures have been added in case it is
technically impracticable from an engineering perspective to
meet the ground water cleanup action levels.
Installation and operation of a treatment system (as
required) to remove hazardous substances from the extracted
ground water, and deep well injection of the extracted
ground water following any required treatment. Ground
water treatment will be required to the extent necessary to
attain maximum allowable concentrations (MACs), which are
levels equivalent to those required for delisting a
hazardous waste under the Resource Conservation and Recovery
Act (RCRA). Treatment beyond the MACs will be required
under certain conditions if either the Lower Eau Claire or
Mount Simon Formation (which are more than approximately
1800 feet below the surface of the site) is an underground
source of drinking water (USDW) as defined in 40 CFR 144.3.
Alternatively, the ground water could be treated to remove
hazardous substances followed by reinjection of the ground
water into the Calumet aquifer in a manner that will prevent
spreading of the salt plume.
Construction of a cover over the' entire site that is
consistent with the closure requirement under Subtitle C of
RCRA
Restriction of site access, and deed restrictions.
Long term monitoring and maintenance.
The ground water treatment or underground injection portions of
the remedial action may be combined with the remedial action for
Midco II. For example, the ground water from Midco I may be
transported to Midco II for treatment or injection, or vice
versa. In these cases, the combined treatment or injection shall
constitute an on-site action, for purposes of the Off-site Policy
and compliance with applicable or relevant and appropriate
standards.
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DECLARATION
The selected remedy, as modified herein, and including the
contingency measures in case EPA determines that it is
technically impracticable to meet the ground water cleanup action
levels, is protective of human health and the environment, and is
cost effective. The selected remedy also attains Federal and
State requirements that are applicable or relevant and
appropriate to this remedial action, except that some primary
Maximum Contaminant Levels will be waived for portions of the
Calumet aquifer, provided that it is demonstrated that it is
technically impracticable from an engineering perspective to
attain these standards and appropriate contingency measures are
implemented.
This remedy satisfies the statutory preference for remedies that
employ treatment that reduces toxicity, mobility or volume as a
principal element, and utilizes permanent solutions and
alternative treatment technologies to the maximum extent
practicable.
Because this remedy will result in hazardous substances remaining
on-site, pursuant to Section 121 (c) of CERCLA, a review will be
conducted at the site within five years after commencement of the
remedial action and at least every five years thereafter to
ensure that the remedy continues to provide adequate protection
of human health and the environment.
Date
Valdas V. Ac
Regional Ac
Region V
imkus
linistrator
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SUMMARY FOR RECORD OF DECISION AMENDMENT
MIDCO I, GARY, INDIANA
I. INTRODUCTION (for more detailed information on the site
location, site description, and the site history, enforcement
activities and community relations prior to June 30, 1989 refer
to the Record of Decision (ROD) signed on June 30, 1989, Sections
I-III)
Midco I operations were primarily conducted on an approximately
four acre area at 7400 W. 15th Avenue (see Figures 1 and 2) from
approximately 1973 through 1979. Operations included storage and
disposal of thousands of drums and a number of tanks of chemical
wastes on the site. Many of these wastes were from the paint
industry, and many contained hazardous substances. During the
operations, wastes were dumped and spilled onto and into the
ground at the site. A large fire in December 1976 destroyed
thousands of drums containing chemicals on the site, and resulted
in additional spillage of chemicals onto the site.
The United States Environmental Protection Agency (EPA) installed
a fence around the site in 1981, and completed a removal action
in 1982 that included removal of all surface wastes including
thousands of drums of chemical wastes and a number of tanks
containing chemical wastes. In addition, the top six inches to
one foot of contaminated soil was removed and a clay cover placed
over much of the site. The contaminated ground water, and
subsurface soil and debris below the soils excavated were not
addressed in the removal action.
A Remedial Investigation/Feasibility Study (RI/FS) was completed
by a group of potentially responsible parties (PRPs) (generally
PRPs are entities who owned or operated Midco I or sent or
transported hazardous substances to the Midco I site) under EPA
oversight from 1985 to 1989. The Indiana Department of
Environmental Management (IDEM) also participated in oversight of
the RI/FS. The RI showed that portions of the subsurface soils,
including natural soils and fill material, located within the
area outlined in Figure 2 are highly contaminated by a large
number of hazardous substances (including volatile organic
compounds (VOCs), semivolatile organic compounds, PCBs, metals
and cyanide). The fill material consists of sandy soil, granular
material, and some cinders and gravel mixed with a lot of
cultural debris including crushed drums, paint waste, wood,
concrete, bricks, and other materials. Ground water below the
site is highly contaminated with VOCs, semivolatile organic
compounds, metals and cyanide, but at the time of sampling the
contaminated ground water did not extend very far from the site
cover boundaries outlined in Figure 2. Some surface sediments
have also been contaminated. Some of the ground water affected
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NOTE LEGEND
SITE LOCATION MAP WAS REPRODUCED ,
FROM THE U.S.G.S. 7.5 MINUTE QUAD.
HAP. HIGHLAND, INDIANA, 1968, PHOTO ciriiPP 1 1
REVISED 1980. REFER TO STANDARD ["»""* V1
U.S.G.S. TOPOGRAPHIC HAP SYMBOLS. WARZYN
APPROXIK^TE ' ^v_ ^
PROPERTY BOUNDARY nOftn
SITE LOCATION MAP
FEASIBILITY STUDY
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30' RADIUS
CIRCLE CENTERED ON tEST PIT I
CIRCLES CENTERED ON TEST PITS
2.4.8. AND 9
DEPTH OF 6 FEET
JJFJAJL-B.
-30' RADIUS
CIRCLES CENTERED ON TEST PIT II
AND MW2
-30' RADIUS
UW7fl
SYMBOL LEGEND:
GRID POINT
MONITORING WELL
LOCATION
TEST PIT LOCATION
MINIMUM AREA FOR
TREATMENT
INITIAL FENCE
LOCATION
SOIL SAMPLE
COLLECTION AREA,
COVER AND FINAL
FENCE BOUNDARIES
SEDIMENTS TO BE
REMEDIATED
DEPTH OF 4 FEET
fifJAJL_A-
HQIfc
I. LINES OEMARKINC THE INITIAL
FENCE LOCATION AND THE SOIL
SAMPLE COLLECTION AREA AND
COVER AND FINAL FENCE BOUNDARIES
ARE COINCIDENT BETWEEN GRID
POINTS B8. AA, AND EE.
^ »nv^i
S-' « 5
* MWJ
-DEPTH OF 4 FEET
FIGURE 2
I5lh ST.
MDCO I REMEDIATION
MDCO I
GARY. INDIANA
ALTISUNATlVli 10
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by the Hideo I operations is highly saline.
After preparing a Proposed Plan and considering public comments,
EPA selected the final remedial actions for the site in the
Record of Decision (ROD) signed on June 30, 1989. IDEM concurred
in the selected remedy. The final remedial actions were to
address the remaining contamination at the site including
contaminated subsurface soil, contaminated ground water and
contaminated surface sediments. The major components of the
remedy selected by EPA in the 1989 ROD included:
On-site treatment of an estimated 12,400 cubic yards of
contaminated soil and waste material by a combination of
vapor extraction (SVE) and solidification/stabilization
(S/S) followed by on-site deposition of the solidified
material.
Excavation and on-site S/S of approximately 1200 cubic yards
of contaminated sediments from surrounding wetlands.
Installation and operation of a ground water pumping system
to intercept contaminated ground water from the site.
Installation and operation of a deep, Class I, underground'
injection well for disposal of the contaminated ground
water; or if a no-migration petition is not approved by EPA,
treatment of contaminated ground water to remove hazardous
substances followed by deep well injection; or treatment of
the contaminated ground water to remove hazardous substances
followed by reinjection of the ground water into the Calumet
aquifer in a manner that would prevent spreading of the salt
plume.
Installation of a final site cover, access restrictions,
deed restrictions, and monitoring.
EPA with participation by IDEM conducted a 120 day negotiation
period with the PRPs from Hay until September 1989, but no
agreement was reached. In November 1989, EPA issued a Unilateral
Administrative Order to a group of PRPs requiring them to
implement the remedial action called for in the ROD. This Order
became effective on December 29, 1989. However, the PRPs did not
agree to implement the Order without addition of conditions that
were unacceptable to EPA. On January 8, 1990, the United States
filed an Amended Complaint seeking to enforce the Unilateral
Administrative Order, as well as to recover EPA's response costs,
punitive damages, and fines.
In 1991, EPA determined that the arsenic data from the Midco I
Remedial Investigation was largely unusable because of an
interference by high concentrations of aluminum in many of the
samples (see Section III). Because arsenic was an important
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factor in determining the extent of soil treatment by S/S at
Midco I, EPA considered the new information on the arsenic data
to be fundamental new information. EPA has therefore
reconsidered the 1989 ROD'S provisions relating to the extent of
soil treatment by S/S, and has at the same time in this ROD
Amendment applied new Agency regulations (e.g. the revised NCP
issued March 8, 1990, 40 CFR 300.430(a)(iii) "(A) EPA expects to
use treatment to address the principal threats posed by the site
wherever practicable (B) EPA expects to use engineering
controls such as containment for waste that poses a relatively
low long-term threat....") dealing with the extent of soil
treatment at Superfund sites. This ROD Amendment also provides
further detail regarding the implementation of various other
components of the 1989 ROD. The revisions to the 1989 ROD are
discussed in more detail later in this document.
EPA, IDEM, and a group of PRPs have since reached a proposed
settlement consistent with this ROD Amendment. This settlement
has been embodied in a Consent Decree that is being submitted for
public comment concurrently with this proposed ROD Amendment. A
detailed Statement of Work that would implement the remedial
action that is the subject of the ROD Amendment is incorporated
in the Consent Decree that is being lodged with the Federal
District Court in Hammond, Indiana for public comment. This ROD
Amendment incorporates the elements of the proposed remedial
action, as well as providing updated information on the site.
The remedy selected in this ROD Amendment includes the following
major components:
On-site treatment of a minimum of approximately 5,200 cubic
yards of contaminated soil and waste material, and possibly
more dependent upon the results of further sampling, by SVE
and in-situ S/S.
Excavation and on-site S/S of contaminated sediments from
the surrounding wetlands.
- Installation and operation of a ground water pumping system
to intercept contaminated ground water from the site.
Contingency measures shall be implemented in case it is
determined that it is technically impracticable from an
engineering perspective to attain the ground water cleanup
action level.
Installation and operation of a treatment system (as
required) to remove hazardous substances from the extracted
ground water, and deep well injection of the extracted
ground water following any required treatment. Ground water
treatment will be required to the extent necessary to attain
maximum allowable concentrations (MACs), which are levels
equivalent to those required for delisting a hazardous waste
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under the Resource Conservation and Recovery Act (RCRA).
Treatment beyond the MACs will be required under certain
conditions if either the Lower Eau Claire or Mount Simon
Formation (which are more than approximately 1800 feet below
the surface of the site) is an underground source of
drinking water (USDW) as defined in 40 CFR 144.3.
Alternatively, the ground water could be treated to remove
hazardous substances followed by reinjection of the ground
water into the Calumet aquifer in a manner that will prevent
spreading of the salt plume. See Section V.A of this ROD
Amendment Summary.
- Construction of a cover over the entire site that is
consistent with the closure requirement under Subtitle C of
RCRA, access restriction, deed restrictions, and monitoring.
The ROD Amendment is similar to the 1989 ROD to the extent that
it utilizes the same remedial technologies for soil and ground
water remediation (ie. soil solidification/stabilization, soil
vapor extraction, ground water extraction, treatment and deep
well injection, and final site cover). The ROD Amendment
utilizes different methods from the 1989 ROD for determining the
amount of soil that must be treated, further defines the
requirements for'an effective site cover over soils with low
levels of contamination that are not being treated, and further
defines the requirements for treatment of ground water prior to
deep well injection. It is expected that less soil and ground
water treatment (see Section V.A) will be required under the ROD
Amendment. In spite of this, the ROD Amendment achieves a level
of protection of public health and the environment that is not
considered significantly different from what would have been
achieved by the 1989 ROD. The ROD Amendment's provisions provide
such protection by providing for treatment of principal threats
(that is the highly contaminated soils) and mandating an
effective site cover over untreated soils that pose a relatively
low long-term threat. The site cover will substantially reduce
the threat from the soils presenting a relatively low long-term
threat: for the direct contact "threat by covering the soil with a
five foot thick cover; and for the threat of further ground water
contamination from the soils above the water table by reducing
infiltration through the soils and production of leachate. To
maintain its effectiveness, the site cover and solidified/
stabilized material will have to be monitored and maintained.
In contrast, the 1989 ROD provided for treatment of soils posing .
a relatively low long-term threat by SVE and S/S. This may have
resulted in permanent treatment of some additional contaminants
and would have resulted in a reduction of leaching and control of
the direct contact threat by the treatment and a cover. However,
in spite of this additional treatment, unrestricted future usage
of the site would not have been allowed because long term
maintenance and monitoring of the solidified/stabilized material
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and the cover would have been required. Any reduction in
protectiveness from the change in the ROD Amendment's soil
treatment action levels (see Section V.C) from the 1989 ROD'S
soil cleanup action levels (see Section IV) are compensated for
by taking into account the risk reducing effect from the site
cover over untreated soils posing low level threats. The ROD
Amendment includes new requirements for the final site cover to
ensure its effectiveness. Because the risk reduction and
reduction in toxicity or mobility of the additional treatment
required in Alternative 8 compared to Alternative 10 is small, it
is not considered to be cost effective compared to Alternative
10.
A Proposed Plan has been prepared that briefly describes the
remedial alternatives analyzed by EPA, proposes the revised
alternative, and summarizes the information relied upon to select
this alternative. This proposed ROD Amendment as well as the
Proposed Plan will be subject to a public notice, public comment
period, and the opportunity for a public meeting, in accordance
with the requirements of 40 CFR 300.435(c). In addition, the ROD
Amendment and supporting information will be made available to
the public in the Administrative Record for this action.
II. PURPOSE OF ROD AMENDMENT
The major purpose of this ROD Amendment is to modify the 1989
ROD'S provisions relating to the extent of soil treatment by S/S,
as a result of new information on the arsenic data. At the same
time, the ROD Amendment applies new EPA regulations (e.g. the
revised NCP issued March 8, 1990, 40 CFR 300.430(a)(iii) "(A) EPA
expects to use treatment to address the principal threats posed
by the site wherever practicable.... (B) EPA expects to use
engineering controls, such as containment for waste that poses a
relatively low long-term threat....") dealing with the extent of
soil treatment at Superfund sites.
This ROD Amendment provides for direct treatment of soils at what
are believed to be the more highly contaminated areas of the
site, which are the source of the principal threats to ground
water, air and dermal contact. Large volumes of soils presenting
a relatively low long-term threat will not be treated since (in
the context of the conditions at this site) the threats from
such soils can be reliably controlled using an effective site
cover.
A minimum of approximately 5,200 cubic yards (depicted in Figure
2) will be treated without further sampling, and additional
amounts may have to be treated depending upon the results of
further sampling.
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The action levels for additional soil treatment outside of the
areas outlined in Figure 2 are as follows:
cumulative lifetime carcinogenic risk = 5 X 10"4
cumulative chronic non-carcinogenic risk index = 5.0
lead concentration (mg/kg) = 1000
These action levels were selected taking into account treatment
of the minimum area for treament identified in Figure 2, site
characteristics and hazardous substances, and current EPA
regulations, policies, and guidance. The cover will be over the
entire site and will be consistent with RCRA Subtitle C closure
requirements. The extent and quality of the site cover under the
1989 ROD was left open (depending upon the success of the
treatment).
Another purpose of this ROD Amendment is to further define the
requirements for treatment prior to deep well injection of the
extracted ground water, including a proposal to delist extracted
ground water (following treatment as required) meeting specified
maximum allowable concentrations (MACs) in accordance with "A
Guide To Delisting of RCRA Wastes For Superfund Remedial
Responses" (September 1990) so that the ground water can be
injected into the lower Mount Simon formation in compliance with
the requirements of RCRA and the Underground Injection Control
Program (see Section V.A for further explanation of MACs). In
effect, treatment to the MACs would take the place of the 1989
ROD'S requirement of treatment to RCRA Land Disposal Restriction
(LDR) treatment standards prior to the deep well injection.
Treatment beyond the MACs will be required under certain
conditions (see Section V.A) if either the Lower Eau Claire or
Mount Simon Formation (which are more than approximately 1800
feet below the surface of the site) is an underground source of
drinking water (USDW) as defined in 40 CFR 144.3.
This ROD Amendment also further defines the remedial action as
follows: . ,
definition of phases and sequencing for ground water and
soil treatment;
further definition of performance standards for S/S;
a decision that the in-situ S/S option allowed in the 1989
ROD will be implemented rather than the excavation option;
a decision that the option of deep well injection without
prior treatment, which would require EPA approval of a no-
migration petition will no longer be considered (Alternative
7);
contingency measures have been added in case it is
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technically impracticable to attain the ground water cleanup
action levels;
further definition of construction requirements for the site
cover;
a determination that air emissions during in-situ S/S and
during SVE conducted with the in-situ S/S equipment shall be
controlled by carbon adsorption or by another technology
that is equally effective;
a determination that in addition to the above if cumulative
air emissions from all operations other than excavation at
the Facility exceed 3 pounds per hour, carbon adsorption or
another technology that is equally effective shall be used
in the ground water treatment system and all SVE;
further definition of actions that will be taken to comply
with the requirements for protection of wetlands in
Executive Order 11990 and Section 404 of the Clean Water
Act.
This ROD Amendment also provides updated information on the site
in the following section.
III. SITE CHARACTERISTICS AND SUMMARY OF RISKS (this Section
updates information on site characteristics and risk in Sections
V and VI of the 1989 ROD)
Some new information has been obtained regarding Midco I, and new
conditions have occurred on the site since the 1989 ROD was
signed. This new information and new conditions are reported in
this portion of the ROD Amendment.
Subsequent to completion of the 1989 ROD, EPA became aware that
the arsenic concentrations reported for some soil and sediment
samples in Midco I the Remedial Investigation, could be inflated
due to an analytical interference from high aluminum
concentrations in these samples. This was significant because
any arsenic concentrations exceeding background would exceed the
1 X 10"^ carcinogenic risk level and require soil treatment by
SVE and S/S under the 1989 ROD. In response, EPA investigated
this concern and determined that the higher arsenic soil
concentrations reported in the RI were unreliable. As a result
the actual extent of soil treatment by SVE and S/S required in
the 1989 ROD would likely have been considerably less than
estimated in the Feasibility Study dated February 1989.
From an EPA audit of some of the soil data, EPA determined that
the arsenic measurements in soil samples with aluminum
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8
concentrations greater than 10,000 mg/kg should be considered
unusable because an adequate background correction for the
aluminum interference was not applied. At Midco I, three soil
boring samples (all within the fenced area outlined in Figure 2),
three test pit samples and ten surface sediment samples exceeded
aluminum concentrations of 10,000 mg/kg. These samples generally
had the highest arsenic results. See also Section III of the
Midco II Summary for Record of Decision Amendment for more
information on the validity of the arsenic data.
If the arsenic values in the soil samples with aluminum
concentrations greater than 10,000 mg/kg are excluded from the
risk calculations, the estimated averaged, site-wide, lifetime,
cumulative, carcinogenic risk due to ingestion of soils using the
future development scenario decreases from 6.8 X 10"5, as
reported in the 1989 ROD, to 5.9 X 10'5 (Table 4-22 of the
Addendum to Public Comment Feasibility Study, February 10, 1989).
The non-carcinogenic risk index for exposure to soils would not
change from the number reported in the 1989 ROD. The revised
soil risks without arsenic were taken into account in determining
the minimum areas for S/S defined in Section V.C, and Figure 2 of
this ROD Amendment.
The 1989 ROD provided for excavation and treatment of
contaminated sediments that were outside the fenced portion of
the site. Unfortunately since the time when the 1989 ROD was
signed, some of the sediment areas that had been designated for
excavation have been filled in. EPA has initiated actions to
identify the party or parties responsible for this filling and to
determine whether it is an ongoing action.
To update the risk assessment calculation procedures for soil
risks, EPA asked Planning Research Corporation (PRC) to conduct
additional risk calculations using the data from the Midco I
Remedial Investigation. The risks reported in the 1989 ROD did
not include dermal contact or inhalation modes of exposure to the
soils. The results of PRC's calculation are presented in a
letter report dated June 21, 1991.- The risks were calculated
using the average soil concentrations in samples from test pits
dug into what was suspected to be the most contaminated areas of
the site during the Remedial Investigation, and using a dermal
contact and inhalation mode of exposure as well as the ingestion
mode of exposure used in the Remedial Investigation. It was
assumed' that a home with a basement would be built on the site
and that as a result the residents would be exposed to soil gas
from the site. Very high carcinogenic risks to on-site residents
were calculated due to inhalation exposures to volatile organic
compounds including: methylene chloride (risk = 1.9);
trichloroethylene (risk = 0.23); and benzene (risk = 0.019).
Very high non-carcinogenic risks to on-site residents were also
calculated due to inhalation exposures to volatile organic
compounds including: methylene chloride (risk index = 290); 2-
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butanone (risk index = 68); and toluene (risk index = 6000). Not
including arsenic or the inhalation mode of exposure, the
calculations indicate a cumulative carcinogenic risk from the
dermal contact and ingestion modes of exposure to be 8 X 10"4;
and the cumulative non-carcinogenic risk index to be 7.5. The
calculations indicate a cumulative carcinogenic risk to
hypothetical construction workers to be 5.8 X 10~6, and a
cumulative non-carcinogenic risk index of 4.2. These revised
risk calculations provide further support of EPA's remedial
action decisions for the Midco I site.
Since the 1989 ROD was completed, the United States Fish and
Wildlife Service (F&W) completed a report entitled: "Summary
Addendum Report for the Midco I, Midco II, and Ninth Avenue Dump
Hazardous Waste Sites in Gary, Lake County, Indiana", September
1990. In this report, F&W concluded that "the various
contaminated habitats/media at Midco I, Midco II, and the 9th
Avenue Dump sites present a threat to fish and wildlife resources
utilizing or exposed to them." This additional documentation
provides further support of EPA's remedial action decisions for
the Midco I site.
IV. DESCRIPTION OF THE REMEDY SELECTED IN THE 1989 ROD
(ALTERNATIVE 8); GROUND WATER PUMPING. TREATMENT AND, DEEP WELL
INJECTION WITH SOIL VAPOR EXTRACTION AND SOLIDIFICATION/
STABILIZATION
The remedy selected in the 1989 ROD (Alternative 7 or 8) combined
either ground water Alternative 4A (Alternative 7) or 4B
(Alternative 8), with soil treatment Alternative 5E.
Implementation of Alternative 7 was contingent upon EPA approval
of a no-migration petition pursuant to 40 CFR 268.6 and 40 CFR
148 Subpart C. After the ROD was approved, EPA obtained
information from review of the Inland Steel and U.S. Steel no-
migration petitions that indicated that it is very unlikely that
a no-migration petition would be approved for deep well injection
at the Midco I site. Therefore, the subsequent discussion uses
only Alternative 8.
Alternative 8 included installation and operation of ground water
extraction wells to intercept the contaminated ground water that
exceeds the ground water cleanup action levels (CALs) identified
in Section X of the 1989 ROD, and installation of a Class I
hazardous waste underground injection well into the Mount Simon
formation for disposal of the highly saline waste water.
The extracted ground water was to have been treated to remove
hazardous substances to the extent required by EPA prior to the
deep well injection. While the extent of treatment that would be
required by EPA was not fully defined, it was anticipated that
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10
this would at least require meeting Land Disposal Restriction
(LDR) treatment standards for listed hazardous waste categories
F001, F002, F003, F005, F007, F008, F009. This was anticipated
to require treatment of the extracted ground water by air
stripping and carbon adsorption. However, Alternative 8 included
provisions for treating to drinking water standards if required
in order to gain approval of the deep well injection. Treating
to drinking water standards was anticipated to require metals
precipitation, and cyanide oxidation in addition to the air
stripping and carbon adsorption.
In the 1989 ROD, no mention was made of delisting the ground
water because at that time no guidance was available on the level
of treatment required to delist ground water. It was anticipated
that delisting the ground water would require more stringent
treatment than meeting the LDR treatment standards.
Another option that was allowed under Alternative 8 was treatment
of the hazardous substances followed by reinjection of the
treated ground water back into the Calumet aquifer in a manner
that would not spread the salt plume in the Calumet aquifer. The
pump, treatment and injection system would be operated until
ground water CALs are attained in the Calumet aquifer.
Contaminated subsurface soils located above the water table were
to have been treated by soil vapor extraction (SVE) and
solidification/stabilization (S/S). In additition, S/S would be
conducted on highly contaminated materials below the water table
that could be handled by localized dewatering. Contaminated
soils below the water table that were not treated would be slowly
remediated by the ground water extraction system through ground
water flushing. At the end of the action, all soils located
above the water table exceeding the soil CALs (Section X of the
1989 ROD) had to be treated by SVE and S/S. The soil CALs were
based on contaminant concentrations that would allow for
unrestricted future usage of the site, and were defined as
follows:
cumulative lifetime carcinogenic risk = 1 X 10"6
cumulative chronic non-carcinogenic index = 1.0
Under Alternative 8, the S/S of the subsurface soils could have
been conducted either by excavation followed by S/S, or by in-
situ S/S. If the excavation option was.used, then SVE was
required to be conducted before the S/S operation to an extent
required to achieve the air emission criteria defined in Section
X of the 1989 ROD, and to attain LDR treatment standards. SVE
was required prior to in-situ S/S to the extent necessary to
achieve the air emissions criteria in Section X of the 1989 ROD,
to assure that leachate from the solidified mass would not cause
exceedance of the ground water CALs, and to allow S/S to proceed
successfully.
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Sediments in the areas shown in Figure 3, would be excavated and
treated on-site by S/S along with the contaminated soils.
Following the S/S, the area treated by S/S would be covered to
meet the requirements of RCRA if the excavation and S/S option
was used, otherwise the quality of the site cover would depend on
the success of the S/S operation. Ground water use restrictions,
access restrictions and long term monitoring were also required.
V. DESCRIPTION OF NEW ALTERNATIVE (ALTERNATIVE 10): GROUND
WATER PUMPING. TREATMENT AND DEEP WELL INJECTION WITH SOIL VAPOR
EXTRACTION AND SOLIDIFICATION/STABILIZATION
A. Ground Water Pumping, Treatment and Disposal
Like Alternative 8 in the 1989 ROD, the new Alternative 10
includes installation and operation of a ground water extraction
system to intercept the contaminated ground water that exceeds
the ground water CALs, and installation of a deep underground
injection well for disposal of the ground water. As stated
before, Alternative 10 proposes to delist extracted ground water-
by meeting specified maximum allowable concentrations (MACs) in
accordance with "A Guide To Delisting of RCRA Wastes For
Superfund Remedial Responses" (September 1990) so that the ground
water can be injected into the lower Mount Simon formation in
compliance with the requirements of RCRA and the Underground
Injection Control Program. Although the 1989 ROD did not mention
delisting of the ground water, it is probable that this same
delisting procedure would have been used under Alternative 8,
because Alternative 8 was worded broadly enough to allow this
procedure, for the same reasons that it is now being proposed for
Alternative 10.
The MACs are defined below. For purposes of compliance with
RCRA, treatment to the MACs would take the place of the 1989
ROD'S requirement of treatment to RCRA LDR treatment standards
prior to the deep well injection.
In accordance with the delisting guidance, a Superfund waste can
be delisted if it attains or is treated to attain levels that
will not cause exceedance of health based levels (HBLs) used for
delisting decisions at a hypothetical receptor well using generic
assumptions and an appropriate ground water transport model such
as the vertical and horizontal spread (VHS) model. The HBLs are
set at concentrations of constituents that provide protection for
drinking water usage (primary Maximum Contaminant Levels (MCLs)
from 40 CFR Part 141 are the HBLs when available, otherwise the
HBL is set at the 10"6 carcinogenic risk level or the level that
will not cause a non-carcinogenic risk assuming that 2 liters per
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FIGURE 3
|L
?
t!
l!
D
ism ST.
SYMBOL LEGEND:
FENCE LOCATION
SEDIMENTS TO BE
REMEDIATED
FIGURE 3
SEDIMENTS TO BE REMEDIATED (FOR ALTERNATIVE 8)
MIDCO I
GARY, INDIANA
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12
day is ingested over a 70 year lifetime). The HBLs for this
action are listed in Appendix I. The VHS model is often accepted
in the RCRA delisting program for use in estimating the extent to
which toxicant leaching from a Subtitle D landfill will be
diluted within a surficial aquifer before it reaches a
hypothetical receptor well 500 feet down gradient. While these
modeling conditions are not designed to fit the conditions for
deep well injection at Midco I, they will be used for the
delisting demonstration in this ROD Amendment because the
delisting determination is generic and is not a site specific
determination, and because the results using these modelling
conditions are conservative for the disposal in a deep well in
this location.
Using the VHS model, the dilution factor derived from the model
depends on the volume of the liquid entering the ground water.
Because the volume of ground water that will be deep well
injected is large, the resulting dilution factor using the model
is 6.3. It follows that the Midco I ground water can be delisted
if the hazardous substances contained in it are or are treated to
be less than 6.3 times the HBLs. The quantity 6.3 times the HBLs
will be referred to as the maximum allowable concentrations
(MACs). Under Alternative 10, EPA proposes to delist the
extracted ground water through this ROD Amendment by providing
for treatment of the extracted ground water to below the MACs
prior to deep well injection. This delisting satisfies the
substantive requirements of 40 CFR 260.20 and 260.22.
The Midco I FS dated February 1O, 1989 and the reviews conducted
for the FS provide documentation that the ground water can be
treated to the MACs. Related information is included in a report
entitled Midco I and II Delistina Demonstration. May 16, 1991.
In addition, a pilot study shall be conducted using the actual
extraction well network. Information from the pilot study will
be used to properly design the treatment system to assure that
the MACs will be met in the treated ground water. After
initiation of the operation, sampling will be conducted on the
treated ground water to verify "that MACs are being met. This
sampling shall be fully defined during the design phase of this
project. Since the ground water will be delisted, the deep
underground injection well for Alternative 10 will meet the
requirements for a non-hazardous injection well rather than
requirements for a hazardous injection well. In particular,
siting requirements in 40 CFR 146.62 Will not be an applicable or
relevant and appropriate requirement (ARAR) for Alternative 10.
Some MACs are higher than the LDR treatment standards for the
same compound, and some are lower. Generally for the less toxic
compounds, the MACs are less stringent than the LDR treatment
standards, while for the more toxic compounds the MACs are more
stringent. This is summarized for some compounds of concern at
Midco I in the following comparison:
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COMPOUND
acetone
chlorobenzene
ethylbenzene
methylene chloride
methyl ethyl ketone
tetrachloroethylene
toluene
1,1,1-trichoroethane
trichloroethylene
xylene
cyanide
chromium
lead
nickel
MACS fMG/L)
25.2
0.63
4.4
0.0315
12.6
0.0315
6.3
1.26
0.0315
63
1.26
0.63
0.95
0.63
LDR (MG/L>
0.05
0.15
0.05
0.2
0.05
0.079
1.12
1.05
0.062
0.05
1.9
0.32
0.04
0.44
More compounds are regulated under the delisting procedures than
have applicable LDR treatment standards.
The end result of using the delisting procedures is that, while
the action is still protective, it may be possible that the MACs
can be attained by air stripping alone, while compliance with the
LDR treatment standards was expected to require treatment by
carbon adsorption in addition to air stripping. However, it is
possible that further treatment by carbon adsorption and metal
precipitation, or alternative treatment processes will be
required to meet the MACs. Waivers of some siting requirements
for deep well injection of hazardous wastes (40 CFR 146.62) will
not be required once the ground water is delisted.
After the ground water has been delisted and has met the MACs, it
will be injected into the lower Mount Simon Formation without
further treatment by means of a deep well constructed according
to Class I non-hazardous underground injection well requirements
if either of the conditions (1 or 2) below is met:
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1. Neither the Lower Eau Claire nor the Mount Simon Formations
below the well site is a USDW as defined in 40 CFR 144.3.
2. The injection of the ground water will not cause (for each
constituent for which a Safe Drinking Water Act Maximum
Contaminant Levels (MCL) exists): a) the exceedance of Safe
Drinking Water MCLs at the point of entry of the injected ground
water into any portion of the Lower Eau Claire Formation or Mount
Simon Formation that is a USDW pursuant to 40 CFR 144.3; or b)
the exceedance of natural background levels present in any
portion of the Lower Eau Clair or Mount Simon Formation that is a
USDW pursuant to 40 CFR 144.3—whichever level is least
stringent.
Preliminary modelling indicates that injection of the ground
water meeting the MACs into the lower Mount Simon Formation will
meet the requirements of 2 above. However, this must be
confirmed using information from sampling and testing conducted
at the injection well location. If the sampling and testing
confirms that the technical premises of the preliminary modelling
are reasonably conservative, the delisted ground water meeting
the MACs will be injected without further treatment. However, if
additional treatment is required to ensure that the requirements
of 2 above will be met, sufficient treatment will be provided to
ensure that the injection of the ground water will meet the
requirements of condition 2 above.
Based on preliminary modelling of the deep well injection, EPA
believes that it is unlikely that deep well injection into the
lower Mount Simon Formation would cause the exceedance of natural
background levels of TDS in the lowermost USDW. However, in the
unlikely event that it is determined based on modelling that deep
well injection into the lower Mount Simon Formation would cause
such an exceedance, this ROD amendment may be reconsidered. This
ROD may also have to be reconsidered in the unlikely event that
the lower Mount Simon Formation is a USDW.
Alternative 10 also includes the following:
1. Like Alternative 8, Alternative 10 includes the option of
treatment of the extracted ground water for hazardous
substances followed by reinjection of the treated ground
water into the Calumet aquifer, if. the reinjection is
conducted in a manner that will not cause spreading of the
salt plume.
2. Midco I. Midco II. and the Ninth Avenue Dump may be treated
as one site for purposes of permitting and compliance with
EPA»s Off-site Policy.
Where two or more noncontiguous facilities are reasonably
related on the bases of geography or on the basis of the
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threat or potential threat to the public health or the
environment, the two facilities may be treated as one for
purposes of permitting and compliance with EPA's Off-site
Policy (see Section 104(d)(4) of the Comprehensive
Environmental Response Compensation and Liability Act
(CERCLA)). Midco I and Ninth Avenue Dump are located within
200 yards of each other and are 2.5 miles from Hideo II.
All three facilities are located in the same industrial area
on former wetlands that have been partially filled. Midco I
and Midco II were part of the same disposal and treatment
operation. All three facilities had organic solvents, heavy
metals and other hazardous substances disposed on the
facility. In addition, Midco I and Midco II have the same
requirements for treatment and deep underground injection of
the ground water. Therefore, based on the similar geography
and threat, the three facilities may be treated as one
facility for purposes of permitting and compliance with
EPA's Off-site Policy if ground water treatment or deep well
injection is combined with Midco II or Ninth Avenue Dump at
the Midco I or Midco II sites, or if a pipeline is
constructed to transport the extracted ground water (before
or after treatment) from Midco I to Midco II or vice versa.
Since combined treatment, deep well injection, and transport
in a pipeline, between facilities would be considered on-site
actions, permits and compliance with EPA's Off-site Policy
for these actions will not be required since the substantive
and administrative requirements of the permits will be
incorporated into the review process for this CERCLA action
(see Section 121(e) of CERCLA and 40 CFR 300.400(e».
3. It will be advantageous to place the deep injection well(s)
outside of the main areas of contamination from the Midco I
and Midco II site because this may lessen the potential for
contamination of aquifers below the Calumet Aquifer during
the installation of the well, and it will be advantageous to
place the deep injection well and ground water treatment
facility outside .of the main areas of contamination from the
Midco I and Midco II sites because that may lessen the
potential for conflict with the construction and operations
for soil treatment and the site cover. Therefore
construction and operation of the deep injection well, and
ground water treatment facility on areas in very close
proximity but outside of the areas, of contamination will be
on-site (consistent with the NCP 40 CFR 300.400(e)(1). This
will include property at the Indiana Department of
Transportation facility located at 7306 West 15th Avenue in
Gary, Indiana.
4. The injection well must be constructed, installed, tested,
monitored, operated, closed and abandoned in accordance with
the substantive requirements and conditions of Subparts A,
B, D, and E of 40 CFR 144, and Subparts A, B, and F of and
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40 CFR 146.
5. Responses to operational problems and implementation of
corrective actions must be in accordance with the
substantive requirements of 40 CFR 146.64, 146.67, 144.12,
144.51(d) and 144.55. This includes the requirements for
construction, monitoring, reporting, well plugging, and
injection well closure as necessary to prevent movement of
any contaminant into a USDW, due to operation of the
injection well. It also includes implementation of remedial
actions to restore any USDW that becomes contaminated as a
result of the operation of the underground injection well
pursuant to Section 3004(u) and 3008(h) of the 1984
Hazardous and Solid Waste Amendments, and Section 1431 of
the Safe Drinking Water Act.
6. Air emissions from an air stripper (or similar device) shall
meet the requirements defined in Section V.D.
7. Until the extracted ground water meets the MACS, the
extracted ground water shall be managed as a hazardous waste
in accordance with the substantive requirements of RCRA.
B. Ground Water Cleanup Action Levels (CALs) and Contingency
Measures in Case of Technical Impracticability:
The ground water CALs in Alternative 10 are unchanged from
Alternative 8. The ground water CALS are summarized below and
calculated in accordance with procedures defined in Appendix II:
Ground water throughout the Calumet aquifer affected by
Hideo I that exceed any of the following risk-based levels
will be recovered and treated (except as provided for in the
procedures defined in Appendix II}. The ground water pump,
treatment and injection system shall be operated until the
hazardous substances throughout the Calumet aquifer affected
by Midco I have been reduced below each of these risk-based
levels (except as provided for in the procedures defined in
Appendix II). Applying the CALs throughout the contaminated
plume is consistent with F.R., Vol. 53, No. 245, P. 51426.
Cumulative Lifetime Carcinogenic Risk = 1 X 10"5
Cumulative Non-carcinogenic Index = 1.0
Primary Maximum Contaminant Levels (40 CFR 141)
Chronic Ambient Water Quality Criteria for aquatic life
(AWQC) multiplied by a factor of 3.9
The ground water CALs have been selected to be protective for use
of the aquifer for residential purposes including drinking water
consumption, and to protect aquatic life from recharge of ground
water affected by the Midco I site.
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Based on information in the Administrative Record, EPA believes
that a ground water extraction system can attain the ground water
CALs. However, the technical practicability of achieving the
ground water CALs from an engineering perspective throughout the
Calumet aquifer cannot be fully determined until the extraction
system has been implemented and the plume response monitored over
time. Before concluding whether it is technically impracticable
to attain the ground water CALs, modifications to the design and
operation of ground water extraction system will be considered,
including:
a) discontinuing operation of extraction wells in areas
where ground water CALs are attained;
b) alternative pumping at wells to eliminate stagnation
points and to increase contaminant reductions;
c) varied or intermittent operation of the system (pulse
pumping) to allow aquifer equilibration and encourage
adsorbed contaminants to partition into ground water;
d) physical repositioning of extraction wells to capture :
alternative flow line/transport pathways to increase
contaminant reductions;
If a ground water extraction system cannot meet the ground water
CALs after ten years of operation and it is determined based on a
demonstration that it is technically impracticable from an
engineering perspective to attain the ground water CALs even
considering the potential changes to the design and operation of
the system listed above, the ground water CALs may be changed to
the lowest acheivable levels. In addition, the selected remedy
may include the contingency measures described below.
a) additional institutional controls to prevent human access
to contaminated ground water • (institutional controls may
include deed restrictions sought voluntarily from owners or
compelled to the extent authorized under any applicable
local and State laws);
b) low-level pumping as a long-term gradient control or
containment measure to prevent recharge of the surrounding
wetlands from exceeding the Ambient Water Quality Criteria
for aquatic life, and to prevent human access to the ground
water exceeding the CALs that are based on drinking water
usage.
Any ARARs based on the primary MCLs that exceed the lowest
achievable levels attainable by the ground water extraction
technology, will be waived by EPA, if EPA in the future makes a
finding of technical impracticability.
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C. Soil Treatment:
Alternative 10, like Alternative 8, includes provisions for
treatment of the subsurface soils by SVE and in-situ S/S. Highly
contaminated subsurface soil located above the water table and
some below the water table will be treated by soil vapor
extraction (SVE) and/or solidification/stabilization (S/S) as
described below. Contaminated soils below the water table that
are not treated by S/S will be slowly remediated by the ground
water extraction system through ground water flushing. Following
is a description of the soil treatment requirements in order of
the phases for the soil treatment.
1. Ground water pump and treatment:
The pump and treatment system will operate for a period of up to
36 months before direct soil treatment by in-situ S/S or SVE is
initiated. The purpose of this is to attempt to reduce volatile
organic compounds (VOCs) prior to the direct soil treatment
operations.
2. In-situ S/S and SVE:
Following the initial period of pumping and treatment and
successful completion of a treatability study and pilot study on
S/S and SVE, portions of the subsurface soils shall be treated by
SVE and in-situ S/S. At least the soils in the areas and to the
depths labeled minimum area for treatment on the map in Figure 2
(which are believed to include the more highly contaminated
soils) will be treated first by SVE and then by in-situ S/S. In
addition, soils outside the mapped areas will be sampled to
determined whether further SVE and S/S will be conducted.
Sampling will be conducted as defined in Appendix III to
determine the full extent of soil treatment outside of the mapped
areas. Using these sampling results, the cumulative risks at
each sample location will be calculated for the ingestion, dermal
contact, and inhalation modes of exposure using the procedures
outlined in the Appendix IV. Based on these results, treatment
by SVE and S/S will be conducted outside of the minimum area to
be treated delineated in Figure 2 if the following soil treatment
action levels are exceeded:
Soil Treatment Action Levels:
cumulative lifetime carcinogenic risk = 5 X 10"4
cumulative chronic noncarcinogenic risk index= 5.0
lead concentration (mg/kg) = 1000
These action levels were selected taking into account treatment
of the minimum area for treatment identified in Figure 2, site
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characteristics and hazardous substances, and current EPA
regulations, policies and guidance.
If these action levels are exceeded for a sample, the soil within
the 20 foot square or 60 foot square (if the square is not
subsampled) represented by this sample will be treated to a depth
of 6 feet, unless sampling indicates that the soil does not
exceed the action levels at depths between 4 and 6 feet, in which
case the soil will be treated to a depth of 4 feet.
The treatment will be first by SVE and then by S/S unless the
exceedance of the Soil Treatment Action Level can be corrected by
removing VOCs, in which case only SVE need be used.
If the treatability study and a pilot study to be conducted on
the in-situ S/S and SVE system show that the equipment used for
the S/S has potential to achieve a 90% reduction in the soil
concentrations of the following VOCs: benzene, methylene
chloride, trichloroethylene, tetrachloroethylene, 1,1,1-
trichloroethane, 1,1-dichloroethylene, trans-l,2-dichloro-
ethylene, and vinyl chloride, and that the air emission
requirements in Section V.D can be satisfied using the S/S
equipment, SVE could be conducted using the same equipment and .
air pollution controls as used for the S/S.1 In this case, the'
fresh air (or possibly heated air or steam) would be injected
into the soil while the blades of the auger mix the soil and
while the contaminated air is drawn off with the induced draft
fan into an air pollution control device. Following the SVE
operation, the same soil that was treated by SVE could be treated
by S/S. The SVE must continue until there is a 97% reduction in
total VOCs (but not less than three times the ambient level) in
the off-gas prior to any air pollution control device during
vigorous agitation of the soils. Air emissions must be
controlled in accordance with the requirements defined in Section
V.D.
Alternatively, SVE would be conducted as a separate operation
from S/S using vacuum and air injection pumps connected by pipes
to a series of air injection and extraction wells. In addition,
a low permeability cover may be required over the area being
treated. The air pressure gradient would draw VOC-contaminated
air from the soil pores. The removed VOCs would be required to
be processed in a liquid-vapor separator and the air emissions
would have to meet the requirements in Section V.D. The SVE must
continue until treatment by in-situ S/S can be conducted in
compliance with the air emission requirements in Section V.D, and
there is a 97% reduction in total VOCs in the soils being treated
1 In conjunction with the treatability study on S/S discussed
in this section, EPA is conducting treatability tests simulating
use of in-situ equipment for conducting the SVE.
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(but not to a concentration less than ten times the detection
limit of each constituent).
It is anticipated that the in-situ S/S system would utilize a
crane-mounted mixing system. The mixing head would be enclosed
in a bottom-opened cylinder to allow closed system mixing of the
treatment chemicals with the soil. The bottom-opened cylinder
would be lowered onto the soil and the mixing blades started,
moving through the depth in an up and down motion, while
chemicals are introduced. An induced draft fan would draw the
contaminated air from the container into an air pollution control
device and exhaust the treated air to the atmosphere. Because
there is potential for causing substantial VOC emissions, the
contaminated air must be treated by carbon adsorption or by
another treatment process that is equally effective, and meet the
criteria in Section V.D. At the completion of mixing at one
location, the blades would be withdrawn and the cylinder removed.
The cylinder would then be operated adjacent to and overlapping
the previous cylinder. This would be repeated until the entire
area is treated.
The formulations and ratios of reagents used for the S/S process
will be established to provide permanent treatment, substantially
reduce release of contaminants due to leaching, substantially
reduce permeability, and to assure long term durability of the
solidified material.
EPA is currently undertaking a treatability study on
approximately ten binders being considered for use in S/S at
Midco I. Those binders selected for use at the Facility must
meet the below listed Minimum Performance Standards. In
addition, based on the results of the treatability study, EPA may
establish Final Performance Standards that are more stringent
than or supplementary to the Minimum Performance Standards.
MINIMUM PERFORMANCE STANDARDS
STABILIZATION OF METALS
Using the Synthetic Precipitation Leaching Procedure (SPLP)
test (method 1312 of SW-846 using extraction fluid #1) the
following percentage reduction in the leachate
concentrations shall be attained using the formula:
SPLP treated X DF / SPLP raw «.<• X 10°
SPLP treated = concentration of constituent (i) in the
leachate from sample treated by S/S
DF = dilution factor = (weight of waste being treated +•
weight of S/S blend added to that waste) / (weight of
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waste being treated)
SPLP rau Mast = concentration of constituent (i) in the
leachate from untreated waste sample
Alternatively, the SPLP tre.te(H can be reduced to the
following Concentration Limits. If a parameter in the
untreated sample is below its Concentration Limit listed
below, no further reduction in leachate concentration is
required, although the treated sample should not increase in
leachate concentration to above the Concentration Limit.
CONSTITUENT PERCENTAGE CONCENTRATION
REDUCTION LIMIT (uq/11
arsenic 90 502
barium 90 20002
cadmium 95 52
chromium 95 1002
copper 95 433
lead . 99 152
nickel 95 1002
vanadium 90 2334
zinc 90 11505
2 These values are from the final or proposed Primary Maximum
Contaminant Standards, 40 CFR Part 141.
3 This value equals the 4-day average fresh water ambient
water quality criteria for copper for protection of aquatic life
times 3.6 at a hardness equal to 100 mg/1. The 4-day average fresh
water ambient water quality criteria is from Ambient Criteria for
Water 1986. EPA 440/5-86-001. The factor 3.6 is the estimated
factor for dilution of the ground water by the surface water at
Midco II. Use of the estimated dilution factor for Midco II is
slightly more conservative than "using the estimated dilution factor
for Midco I.
4 This value was calculated for a non-carcinogenic risk index
equal to unity due to vanadium alone using the reference dose and
procedures outlined in Appendix II.
5 This value is equal to the 24-hour average fresh water
ambient water quality criteria for zinc for protection of aquatic
life times 3.6. The ambient water quality criteria value is from
Quality Criteria for Water 1986. EPA 440/5-86-001. The factor 3.6
is the estimated dilution of ground water by the surface water at
Midco II. Use of estimated the dilution factor for Midco II is
slightly more conservative that use of the estimated dilution
factor for Midco I.
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STABILIZATION OF ORGANICS
Using total waste analyses (using methylene chloride
extraction for semivolatile organics, and methanol
extraction for volatile organics), a 50% reduction in
concentrations shall be attained based on total waste
analyses of the sample of untreated waste (TWA r8H Maste ) and
the sample treated by S/S (TWA tpeated ) calculated in
accordance with the formula: TWA treated X DF / TWA Paw Haste X
100 for the following compounds: anthracene; bis(2-
ethylhexyl) phthalate; ethyl benzene; fluoranthene;
naphthalene; phenanthrene; phenol; toluene; xylene.
PHYSICAL TESTS
i. Using method EPA 9100 from SW-846 (constant head, tri-
axial with back pressure and air free water), the hydraulic
conductivity of the material treated by S/S shall be less
than or equal to 1 X 10"7.
ii. Using method ASTM D1633-84, the unconfined compressive
strength of the material treated by S/S shall be greater
than 50 psi.
iii. Using ASTM D4843, the wet-dry durability test on the
material treated by S/S shall result in less than a 10%
weight loss.
iv. Using ASTM D4842, the freeze-thaw durability test on
the material treated by S/S shall result in less than a 10%
weight loss.
D. Requirements for Air Emissions:
1. Air emissions from the S/S system and from any SVE using the
S/S system shall be controlled using carbon adsorption or
another treatment process that is equally effective.
2. Air emissions from the (i) ground water treatment, (ii) the
soil S/S, (iii) SVE using the S/S system, or (iv) SVE
separate from the S/S system shall be controlled to the
extent necessary to assure that each operation does not have
the potential to result in exposures to a hypothetical
resident located at the Facility boundary that would cause
an estimated cumulative, incremental, lifetime carcinogenic
risk exceeding 1.0 X 10"7, or from causing a non-
carcinogenic risk index greater than 1.0. The risk levels
will be calculated in accordance with the procedures
outlined in Attachment V. Ambient air monitoring and air
emission monitoring shall be conducted to determine whether
this criteria is being met. The air emission monitoring
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data shall be input into an air model to estimate the
potential exposure rates in order to determine whether
controls such as carbon adsorption or other controls will be
required for the emission sources. For the soil S/S system
and SVE using the S/S system such controls (if any) shall be
in addition to the controls required by paragraph D.I.
Since there are multiple operations that cause air emissions
as well as fugitive sources that can not be controlled, each
operation that can be controlled must be controlled to the 1
X 10"7 risk level to assure that the total risk will be less
than 1 X 10"6. In addition, since some nearby residents and
workers may have already been exposed to the chemicals at
Midco I during its operation, it is imperative that this
emission criteria be met.
3. In addition to the requirements of paragraphs 1 and 2 above,
if cumulative emissions of VOCs as defined under the Clean
Air Act from all operations at the Facility other than
excavation exceed 3 pounds per hour, carbon adsorption or
another technology that is equally effective shall be used
to control air emissions from the ground water treatment
system and all SVE.
4. Air emissions must be monitored and controlled to the extent
necessary to comply with applicable OSHA regulations, and
applicable applicable State of Indiana air regulations,
including Title 326 Indiana Administrative Code 6-4 for
fugitive dust.
5. The effective stack height for air emissions from the ground
water treatment, S/S, and SVE must be at least 30 feet above
ground level.
6. For any carbon adsorption unit that is being or has been
used for control of air emissions for the ground water
treatment system, the S/S.system or the SVE conducted with
the S/S system, access to the unit shall be restricted
within 3 feet of the unit. For any carbon unit that is
being or has been used for control of air emissions for SVE
conducted as a separate operation from the S/S, access to
the unit shall be restricted within 10 feet of the unit.
E. Handling and Treatment of Surface Sediments and Soils Beneath
the Sediments:
The surface sediments in areas outlined in Figure 2 will be
excavated to a depth that will leave the soils below the
excavation less than the following soil CALs:
cumulative lifetime carcinogenic risk = 1.0 X 10
•6
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cumulative chronic non-carcinogenic index= 1.0
These sediments and soils will be consolidated on-site and
treated by S/S along with the subsurface soils. Note that the
sediments to be excavated as shown in Figure 2 is reduced in area
due to filling of sediments since the 1989 ROD (compare to Figure
3). EPA is not requiring excavation of the sediments covered by
fill because the risks to human health and the environment from
the sediments that were covered is insignificant.
F. Site Cover, Access Restrictions, Long Term Monitoring, and
Further Remedial Actions:
For Alternative 10, a cover shall be installed over the Cover
Boundary area outlined in Figure 2 following the soil treatment
outlined in Section II.C. above. This cover shall meet or exceed
the requirements for RCRA Subtitle C closure. This cover shall
be designed to provide long term minimization of infiltration,
minimize maintenance, promote drainage, and minimize erosion.
These requirements will be deemed satisfied by a cover which
consists of multiple layers including:
- a top layer consisting of a vegetated component, and a 24 •
inch soil layer comprised of topsoil and/or fill soil with a
surface slope of at least 3 percent and not more than 5
percent;
a geofilter in between the upper layer of soil and the
middle layer of drainage material;
- a drainage layer of either 12 inches of soil with a minimum
hydraulic conductivity of 1.0 X 10"2 cm/sec or a
geosynthetic material with equivalent performance
characteristics, and with a final bottom slope of at least 3
percent;
- a low permeability layer with 24 inches of compacted soil
with a maximum in place saturated hydraulic conductivity of
1.0 X 10'7 cm/sec.; and
- Details of the site cover design shall also be consistent
wi.th the EPA Guidance entitled TECHNICAL GUIDANCE DOCUMENT
EPA/530-SW-89-047 (July 1989) FINAL COVERS ON HAZARDOUS
WASTE LANDFILLS AND SURFACE IMPOUNDMENTS.
Access restrictions will be imposed including installation of a
six foot chain link fence, warning signs and possible deed
restrictions. Deed restrictions limiting development and the
placement of new wells will be sought voluntarily from owners or
compelled to the extent authorized under any applicable local and
State laws.
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As in Alternative 8, the final site cover and access restrictions
must be consistent with hazardous waste landfill closure
requirements of the RCRA (40 CFR 264.111, 264.116, 264.117, and
264.310).
Following attainment of ground water CALs, ground water
monitoring will continue for at least 15 years. The ground water
monitoring must be consistent with the substantive requirements
for ground water monitoring in 40 CFR 264.98, and where necessary
264.98(g) and 264.99.
If a ground water CAL is exceeded during this period due to a
release from the Midco I site, the site cover shall be upgraded
or repaired as needed; operation of the ground water pump
treatment and underground injection system will be reinitiated;
and steps will be taken to meet the ground water CALs. These
actions must be consistent with the substantive requirements of
40 CFR 264.100 (except that the relevant ground water protection
standards shall be the ground water CALs as defined in this ROD
rather than concentration limits specified pursuant to 40 CFR
264.92).
G. Other ARARs and Applicable Regulations included in
Alternative 8:
1. The requirements of Executive Order 11990, Protection of
Wetlands, 40 CFR 6, Appendix A; and Clean Water Act Section 404,
40 CFR 230 and 231 shall be met. Contaminated wetlands will be
replaced off-site at an appropriate ratio. This may be
undertaken as part of an agreement between PRPs and the natural
resources trustees.
2. The area of remediation must comply with the Migratory Bird
Treaty Act.
3. Any residuals (such as spent activated carbon) from the
ground water or soil treatment processes shall be considered a
RCRA hazardous waste.6 Therefore, these residuals must be
stored on site, and disposed of or treated on-site or off-site in
accordance with RCRA regulations, including the LDRs in 40 CFR
268, and 40 CFR 264 Subpart X for residues that are sent off site
to be regenerated. It is possible that, metals sludge from the
ground water treatment process could be treated by S/S on-site,
if Land Disposal Restriction requirements are met.
6 The contaminated ground water and soil contains the
following RCRA listed hazardous wastes: F001; F002, F003, F005,
F007, F008, F009.
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Any debris (such as tree trunks or crushed drums that can not be
properly incorporated into the solidified mass) encountered
during the S/S process or during excavations must be properly
handled and stored on-site, and subsequently properly disposed of
off-site or contained under the final cover, if degradation of
the debris will not cause site cover maintenance problems. Any
containerized or drummed liquid wastes encountered during the
remedial actions shall be properly stored on-site and properly
disposed of off-site.
Any off-site transportaion, treatment, or disposal must be in
compliance with DOT and RCRA requirements (including LDRs), other
applicable State and Federal regulations, and EPA's Off-Site
Policy.
VI. SUMMARY OF THE COMPARATIVE, ANALYSIS OF ALTERNATIVES
This Section updates the evaluation in Section IX of the 1989
ROD. The 1989 ROD justified the elimination of alternatives
other than Alternatives 7 and 8. It is now known that
Alternative 7 should not be further considered. Therefore, this
evaluation will only compare Alternative 8 to the new Alternative
10.
The following table compares some of the critical elements of
Alternative 10 with Alternative 8.
AREA OF COMPARISON ALTERNATIVE 8 ALTERNATIVE 10
MEANS TO ADDRESS GROUND GROUND WATER NO CHANGE
WATER CONTAMINATION EXTRACTION SYSTEM
GROUND WATER CALS CR7 = 1 X 10"5 NO CHANGE
NCRI8 =1.0
PMCLS9
7 Cumulative Lifetime Carcinogenic Risk calculated for each
ground water sampling location using the assumptions and procedures
in Appendix II.
8 Cumulative non-carcinogenic risk index calculated for each
ground water sampling location using the assumptions and procedures
in Appendix II,
9 Primary Maximum Contaminant Levels (40 CFR 141).
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MEANS OF GROUND WATER
DISPOSAL
GROUND WATER TREATMENT
REQUIREMENTS FOR
COMPLIANCE WITH RCRA
PRIOR TO DEEP WELL
INJECTION
MEANS TO ADDRESS
PRINCIPAL THREATS FROM
SOIL CONTAMINATION
AWQC10 X 3.9
DEEP WELL INJECTION NO CHANGE
OR INJECTION INTO THE
CALUMET AQUIFER IN A
MANNER THAT WILL NOT
SPREAD THE SALT PLUME
RCRA LAND DISPOSAL
RESTRICTIONS (BEST
DEMONSTRATED LEVELS
AVAILABLE TECHNOLOGY)
(LDRs)
RCRA DELISTING (6.3
TIMES HEALTH BASED
MACS)
11
TREAT BY SVE AND NO CHANGE
S/S. SVE AND S/S
WILL PROVIDE
PERMANENT TREATMENT
OF HIGHEST CONTAMINATED
AREAS LOCATED ABOVE
AND BELOW THE WATER
TABLE. S/S MATERIAL
WILL BE PROTECTED WITH
A SITE COVER, AND
MONITORED AND
MAINTAINED OVER LONG
TERM.
10 Chronic Ambient Water Quality Criteria for aquatic life.
The AWQC values used in this ROD Amendment are listed in Appendix
II. .
11 Health-Based Levels (HBLs) are concentrations of hazardous
constituents that are used in the RCRA program for making decisions
regarding whether a waste that is regulated as a hazardous waste
under RCRA because it is listed under 40 CFR Part 261, Subpart D
can be' delisted so that it is no longer regulated as hazardous
waste under RCRA because it is listed. In a delisting petition, it
must be demonstrated that the HBLs will be met in a hypothetical
receptor well. The HBLs are set at concentrations of constituents
that provide protection for drinking water usage (Maximum
Contaminant Levels from 40 CFR Part 141 are the HBLs when
available, otherwise the HBL is set at the 10"6 risk level or the
level that will not cause a non-carcinogenic risk assuming that 2
liters per day is ingested over a 60 year lifetime). See Section
V.A.
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MEANS TO ADDRESS RISKS
FROM SOILS THAT ARE
ABOVE THE WATER TABLE
AND THAT PRESENT A LOW
LONG TERM THREAT VIA
GROUND WATER AND
DIRECT CONTACT
TREAT BY SVE AND
S/S. LONG TERM
MAINTENANCE &
MONITORING OF THE
S/S WOULD BE
REQUIRED. THIS
WOULD PROVIDE SOME
PERMANENT TREATMENT
REDUCE LEACHING TO
GROUND WATER, AND
REDUCE DIRECT
CONTACT THREAT BY
S/S AND COVER OVER
THE S/S.
SOIL TREATMENT ACTION
LEVELS
CR
NCRI
1 X 10
1.0
-6
CONSTRUCT A RCRA
SUBTITLE C COVER.
LONG TERM MAINT. &
MONITORING OF THE
COVER WOULD BE
REQUIRED. AS LONG AS
COVER IS MAINTAINED
, IT WILL
SUBSTANTIALLY
REDUCE LEACHING
AND THE DIRECT
CONTACT THREAT
BY COVERING WITH
A FIVE FOOT THICK
COVER.
AT A MINIMUM TREAT
MINIMUM AREA FOR
TREATMENT IN FIGURE
2. OUTSIDE THIS
AREA:
CR = 5 X 10-*
NCRI =5.0
ESTIMATE OF QUANTITY
OF SOIL TO BE TREATED
PERFORMANCE STANDARDS
FOR S/S
12,400 CUBIC YD.12 7,800 CUBIC YD.13
FOR IN-SITU S/S
ASSURE ATTAINMENT
OF GROUND WATER
CALS.
SPECIFIC
PERFORMANCE
STANDARDS FOR
BOTH INORGANICS
AND ORGANICS BASED
ON TESTS ON S/S.
CRITERIA FOR SVE
CONDUCTED PRIOR TO . WILL DEFINITELY BE
S/S TO THE EXTENT CONDUCTED IN ALL
NECESSARY TO MEET AREAS BEING S/S'ed
AIR EM-ISSION CRITERIA TO REDUCE VOCs IN
AND GROUND WATER CALS SOILS BY 97% IF
BASED ON MODELLING CONDUCTED AS A
SEPARATE OPERATION,
AND BY 90% OF
CERTAIN VOCs IF
CONDUCTED WITH IN-
SITU S/S EQUIPMENT.
12
This estimate is probably biased high because it is
partially based on unreliable arsenic data (see Section III).
13 This is a very rough estimate that assumes 50% more than
the minimum amount will be treated as a result of further sampling.
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MEANS TO ADDRESS RISKS
FROM SOILS BELOW THE
WATER TABLE THAT WILL
NOT BE TREATED BY S/S
MEANS TO ADDRESS
CONTAMINATION OF
SURFACE SEDIMENTS
SOIL/SEDIMENT CALS
AIR EMISSIONS CRITERIA
SITE COVER
SPECIFICATIONS
ACCESS RESTRICTIONS,
DEED RESTRICTIONS,
LONG TERM MONITORING
AN ESTIMATE OF THE
PRESENT WORTH
SOILS WILL
GRADUALLY BE
REMEDIATED BY THE
GROUND WATER
EXTRACTION OPERATION.
EXCAVATION AND ON-
SITE S/S
CR = 1 X 10'6
NCRI =1.0
CR = 10'r TO
NEAREST RESIDENTS
AND WORKERS FOR EACH
EMISSION SOURCE, TO
ASSURE ATTAINMENT OF
CR = 10"6 OVERALL.
FOR IN-SITU S/S
DEPENDED ON RESULTS
OF S/S
REQUIRED
NO CHANGE
$14 MILLION
u
NO CHANGE
NO CHANGE
SAME AS ALT. 8
CRITERIA, PLUS NO
GREATER THAN 3
LBS PER HOUR, AND
EMISSION CONTROLS
REQUIRED ON S/S
SYSTEM.
CONSISTENT WITH
RCRA SUBTITLE C :
NO CHANGE
$10 MILLION15
In Alternative 10 the extracted ground water must meet the MACs
prior to deep well injection rather than meet the LDRs, which
were expected to be used in Alternative 8. Treatment to the MACs
is as protective or more protective than treatment to the LDRs
because generally the.MACs are-more stringent for the more toxic
compounds. However, treatment to the LDRs would be more
difficult. Modelling will be conducted to confirm that injection
of extracted ground water meeting the MACs (into the lower Mount
Simon Formation) will be protective of drinking water aquifers.
14 This is a very rough cost estimate from the Feasibility
Study and is likely biased high because it was partially based on
unreliable arsenic data for the extent of soil treatment
Section III).
(see
15 This is a very rough estimate based on the assumption that
50% more than the minimum amount of soil is treated, that SVE
increases the cost of S/S by 50%, and certain ground water
treatment assumptions.
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In Alternative 10, treatment beyond the MACs will be conducted if
necessary to be protective of drinking water aquifers. See
Section V.A.
In Alternative 10, areas of the site having soils located above
the water table with calculated risks below CR = 5 X 10"4 and
NCRI = 5.0, will be covered consistent with RCRA Subtitle C
requirements without being treated by S/S or SVE. However, the
site cover will not be installed until the ground water
extraction system has operated for a few years. Such operation
may further reduce VOCs prior to installation of the site cover.
EPA considers that following treatment of the highly contaminated
areas, the site cover will provide overall protection to CR =
1 X 10"6 and NCRI =1.0 levels. The cover will be multi-layered
and five feet thick. The cover will substantially reduce the
infiltration into the soil and, therefore, reduce the
contamination of the ground water. It will provide an effective
barrier to direct contact while it is maintained. During its
operation any contaminants leached from the soils would be
recovered by the ground water extraction system. In the unlikely
event that long term leaching causes the ground water to exceed
the ground water CALs, the ground water extraction system would
continue to operate or be reactivated so that protection from any
ground water threat is assured.
In Alternative 8, compared to Alternative 10, VOCs in the lower
contaminated areas may have been further reduced by operation of
the SVE system, and the mobility of metals and other organics
reduced by the S/S. However, as mentioned before for Alternative
10, any additional leachate from the soils would be recovered in
the ground water extraction system so that protection from any
ground water threat is assured. Alternative 8 may provide some
additional protection compared to Alternative 10 from the direct
contact threat in case the site cover is severely disturbed in
the future because the low contaminated soils would be treated by
S/S. However, it appears to be very unlikely that a five foot
site cover would be so completely removed, and even if it was
Alternative 10 provides for treatment of the most highly
contaminated soils so that only the lesser contaminated soils
would remain.
Since the time of the 1989 ROD, specialists in S/S treatment have
developed specific tests for testing the permanence of S/S
treatment for inorganics and organics. Therefore, these tests
have been incorporated into Alternative 10 of this ROD Amendment.
Because of the difficulty in reasonably modelling the impact of
VOCs on the ground water, it was decided to simply require SVE to
provide substantial removal of the VOCs prior to treatment by
S/S. The criteria is less stringent for conducting SVE with the
in-situ S/S equipment compared to using a separate operation
because it is much more difficult to monitor the removal of VOCs
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from the soils using the in-situ S/S equipment because the soil
is treated by S/S immediately after the SVE operation.
The three pounds per hour limit on air emissions for Alternative
10 was added to be consistent with EPA's policies on control of
photochemical oxidants. Because the emissions from the in-situ
S/S operation could be substantial and unpredictable, it was
decided that air emissions from the in-situ S/s system must be
controlled.
A. Threshold Criteria: protection of human health and the
environment; and attainment of applicable, and relevant and
appropriate requirements (ARARs):
Both Alternatives 8 and 10 would be protective of human health
and the environment, by extraction and treatment of the ground
water, by treating the highly contaminated soils and sediments,
and by cover installation. Both alternatives are expected to
protect aquatic life in surrounding surface waters from hazardous
substances from the Midco I site including attainment of Ambient
Water Quality Criteria for aquatic life16 and restore the
Calumet aquifer to drinking water quality17 including attaining:
the Primary Maximum Contaminant Levels.
Both include deep well injection of the treated ground water (or
reinjection into the Calumet aquifer in a manner that will not
spread the salt plume). Both would comply with the RCRA LDRs
prior to injection of the ground water: Alternative 8 by
treating to LDR treatment standards; and Alternative 10 by
delisting. Both include soil treatment by S/S and SVE. Both
include excavation and S/S of contaminated sediments. Finally
both include installation of a cover and site access
restrictions.
While Alternative 8 includes treatment of a greater volume of
soils than Alternative 10, the level of protection provided by
Alternative 10 is not considered to be significantly different
from the level of protection provided by Alternative 8 because
low level contaminated soils will be contained by an effective
cover that is consistent with RCRA Subtitle C closure
16 Except possibly for the Ambient Water Quality Criteria for
solids (dissolved) and salinity, for which a ground water CAL is
not being applied since adjacent sources of this contaminant exist
and are not being remediated.
17 Except for total dissolved solids, chlorides, sodium and
potassium, for which a ground water CAL is not being applied since
adjacent sources of these contaminants exist and are not being
remediated.
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requirements, and access to the site will be restricted.
Furthermore, the additional soil treatment in Alternative 8 would
not allow unrestricted future usage of the site because the S/S
material and site cover would require long term monitoring and
maintenance.
Under Alternative 10, if it is determined that it is technically
impracticable from an engineering perspective to attain the
ground water CALs by a ground water extraction system,
contingency measures may be implemented (see Section V.B). These
contingency measures will maintain protection of human health and
the environment by institutional controls, by attaining the
lowest achievable levels in the ground water, and by containment
measures, as appropriate. If it is demonstrated that some
primary MCLs, which are used in the ground water CALS, can not be
attained in some portions of the aquifer due to technical
impracticability, these ARARs will be waived provided that
appropriate contingency measures are implemented.
B. Balancing Criteria: long term effectiveness and permanence;
reduction in toxicity mobility and volume; short-term
effectiveness; implementability; and cost:
The short term effectiveness of Alternative 10 is expected to be
essentially the same as Alternative 8. The pump, treatment and
injection system will be installed first in Alternative 10.
Access to the site will be controlled; so the delay in the soil
treatment will not cause any health impact. For both
Alternatives, VOC air emissions during the remedial actions may
be the short term impact of most concern. These emissions should
be controllable using carbon absorption or another treatment
process that is equally effective.
Both Alternative 8 and 10 employ treatment technologies—ground
water extraction and treatment, S/S, and SVE—that are expected
to perform to substantially reduce the toxicity, mobility, or
volume of hazardous substances-at the Midco I site. Both
Alternatives 8 and .10 provide for long-term effectiveness and
permanence through soil treatment by S/S and SVE, by ground water
extraction and treatment, deep well injection of treated ground
water, site cover, long term maintenance, and ground water
monitoring.
While Alternative 10 will result in treatment of a lower volume
of soils than Alternative 8, Alternative 10 provides for a
reduction of the toxicity and mobility of the more highly
contaminated soil at Midco I. Furthermore, the additional soil
treatment in Alternative 8 will not result in a reduction in the
long term monitoring or maintenance requirements nor allow
unrestricted future usage of the site. In the context of
conditions at this particular site, the use of engineering
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controls such as site cover coupled with long-term (permanent)
maintenance and monitoring of the site cover and ground water to
address any remaining risks posed by soils with low level
contamination is consistent with EPA's expectations for remedy
selection regarding treatment of principal threats and use of
controls for lower level threats as set forth in 40 CFR
300.430(a)(1)(iii) of the National Contingency Plan promulgated
on March 6, 1990.
Alternatives 8 and 10 are identical in implementability in most
respects, and no major problems in implementation are expected.
Very rough, estimates of the costs of Alternative 8 and
Alternative 10 in millions of dollars are compared in the
following Table.
CAPITAL ANNUAL O&M PRESENT WORTH
Alternative 8 9 0.53 14
Alternative 10 7 0.46 10
Typically cost estimates in the Feasibility Study are expected to
have an accuracy of plus 50% to minus 30%. There is more than '
the usual amount of uncertainty in the costs for both Alternative
8 and Alternative 10. However, Alternative 10 may be less
expensive than Alternative 8 primarily because most likely less
soil will be treated, ground water treatment requirements may be
reduced, and the sequence of implementation of remedial actions
(see Section V.C.I, V.C.2, and V.F) will be changed. Because the
risk reduction and reduction in toxicity or mobility of the
additional treatment required in Alternative 8 is small, it is
not considered to be cost effective compared to Alternative 10.
Time for completion of the project depends on how fast the ground
water CALs are attained. All other portions of the project are
expected to be completed in no more than six years.
C. Modifying Criteria: support agency acceptance; community
acceptance:
The Indiana Deparment of Environmental Management, involved in
the process that lead to this ROD Amendment, formally concurred
with U.S. EPA's remedy selection in this ROD Amendment in a
letter dated January 6, 1992.
U.S. EPA prepared a Draft Proposed ROD Amendment and a fact sheet
explaining the ROD Amendment, and held a public comment period on
the proposed ROD Amendment from February 7 through March 14,
1992. The Proposed Plan was mailed to approximately 300 persons
in the communities near Midco I. The Draft Proposed ROD
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Amendment was available for review in the Hammond Department of
Environmental Management and at the Gary Public Library. The
Administrative Record for this action was available for review at
the Region V, U.S. EPA, Chicago office. A public meeting was
held on the proposed ROD Amendment on February 20, 1992.
One comment on the proposed ROD Amendment was received during the
public meeting, and written comments were received from the Grand
Calumet River Task Force and from U.S. Reduction Co. U.S. EPA's
full response to these comments are included in the
Responsiveness Summary, which is Appendix VI of this ROD
Amendment, and is an integral part of this ROD Amendment.
The comment from the Grand Calumet River task force expressed
concern about the public health and environmental protectiveness
of the deep well injection operation and recommended use of a
desalination plant for final disposal of the salt contaminated
ground water, instead of deep well injection. In response to
these comments, U.S. EPA describes the importance of the cost
effectiveness of the remedy, and the precautions that will be
taken to assure that the deep well injection process is conducted
safely and in a manner that will be protective of human health
and the environment.
The comment at the-public meeting had to do with the completeness
of the remedy apparently related to soil treatment by
solidification/stabilization and disposal of ground water by deep
well injection. In response to this comment, U.S. EPA explained
the basis for its belief that treatment by solidification/
stabilization would be effective, and that the deep well
injection process would be conducted in a manner that will be
protective of human health and the environment.
The comments from U.S. Reduction had to do with the completeness
of the Administrative Record for the risk assessment, selection
of deep well injection, and selection of solidification/
stabilization. U.S. Reduction also recommended that additional
investigations be conducted. Xn response to these comments, U.S.
EPA described in detail how the Administrative Record supports
the risk assessment, and the selection of the deep well injection
procedure, and solidification/stabilization.
No changes were made to this ROD Amendment as a result of the
review of the public comments other than incorporating this
section of the Summary for Record of Decision Amendment and the
Responsiveness Summary, indicating that the State of Indiana
concurs in the remedy selection, and removing a reference in the
Declaration that the administrative record would be updated at a
later date to address public comments. However, U.S. EPA hereby
notes that an error was made on page 8 of the Summary for ROD
Amendment, where the estimated risk of soil ingestion without
considering arsenic should be 4.2 X 10*s instead of 5.9 X 10"5.
-------
35
This error does not affect, U.S. EPA's analysis or selection of
remedial actions in this ROD Amendment.
VI. STATUTORY DETERMINATIONS
Based on the description and evaluation of alternatives in the
ROD Amendment, EPA selects Alternative 10 for implementation at
Midco I. This Alternative is described in Section IV of this ROD
Amendment.
Alternative 10, including the provision of contingency measures
in case it is technically impracticable to attain ground water
CALs, will be protective of human health and the environment, and
will be cost effective. ARARs shall be attained except that some
primary MCLs will be waived in portions of the Calumet aquifer,
provided that it is demonstrated that it is technically
impracticable from an engineering perspective to attain these
standards, and that appropriate contingency measures are
implemented. The remedy satisfies the statutory preference for
remedies that employ treatment that reduces toxicity, mobility or
volume as a principal element and utilizes permanent solutions
and alternative treatment technologies to the maximum extent
practicable.
The State of Indiana concurs in the selected remedial actions.
Because the remedy will result in hazardous substances remaining
on-site above health-based levels that would allow for
unrestricted use, a review will be conducted within five years
after commencement of remedial actions to ensure that the remedy
continues to provide adequate protection of human health and the
environment.
-------
36
APPENDICES TO MIDCO I RECORD OF DECISION AMENDMENT
I. HEALTH BASED LEVELS FOR RCRA DELISTING FOR MIDCO I
II. PROCEDURES FOR CONDUCTING RISK BASED CALCULATIONS AND
DETERMINATION OF GROUND WATER CLEANUP ACTION LEVELS AT MIDCO I
III. PROCEDURES FOR DETERMINING THE EXTENT OF TREATMENT FOR
SOILS AND DEBRIS AT MIDCO I
IV. PROCEDURES FOR CONDUCTING RISK BASED CALCULATIONS FOR THE
EXTENT OF SOIL TREATMENT AT MIDCO I
V. PROCEDURE FOR CONDUCTING RISK CALCULATIONS FOR AIR EMISSIONS
VI. RESPONSIVENESS SUMMARY
-------
37
CALs :
delisting :
EPA :
F&W :
HBLs
IDEM :
LDR :
MACS :
MCLs
mg/kg
GLOSSARY
cleanup action levels.
If a waste fits the definition for a listed
hazardous waste under RCRA, it can only be removed
from regulation under RCRA by meeting the
delisting requirements pursuant to 40 CFR 260.22.
United States Environmental Protection Agency.
United States Fish and Wildlife Service.
health based levels used by EPA to make delisting
decisions.
Indiana Department of Environmental Management.
Land Disposal Restrictions under RCRA.
Maximum allowable concentrations. This term is
defined in "A Guide to Delisting of RCRA Wastes
for Superfund Remedial Responses" (9347.3-09FS) to
be the maximum concentration in a waste or in a
leachate from a waste that will still allow the
waste to be delisted.
Maximum Concentration Limits as defined under the
Clean Water Act (40 CFR 141 and 143.
concentration of a constituent in soil expressed
in milligrams of the constituent per kilogram of
soil.
no migration petition; A petition submitted to EPA pursuant to
40 CFR 268.6 and 148 Subpart C that must
demonstrate that deep well injection of a waste
will not cause migration out of the injection zone
within 10,000 years. EPA approval of such a
petition is required prior to deep well injection
of a hazardous waste restricted from land disposal
under the LDRs without treatment to the LDR
treatment standards.
PCBs
PRC
polychlorinated biphenols
Planning Research Corporation, Chicago, Illinois.
-------
38
PRPs
RCRA
RI/FS
ROD
SVE
S/S
USDW
VOCs
VHS
potentially responsible parties. These generally
include the site owners, site operators and
entities that disposed of or arranged for disposal
of wastes containing hazardous substances at the
site.
Resource Conservation and Recovery Act.
Remedial Investigation/Feasibility Study.
Record of Decision.
soil vapor extraction treatment.
solidification/stabilization treatment.
underground source of drinking water as defined in
40 CFR 144.3.
volatile organic compounds.
Vertical Horizontal Spread model for modelling
spread of contamination in the ground water.
-------
APPENDIX I
HEALTH-BASED LEVELS AND SOLUBILITIES
FOR CONSTITUENTS OF CONCERN IN DELISTING PETITIONS
July 1991
CAS No.
83 32 9
67 64 1
75 05 8
98 86 2
107 02 8
79 06 1
107 13 1
309 00 2
62 53 3
7440 36 0
140 57 8
7440 38 2
7440 39 3
56 55 3
71 43 2
92 87 5
50 32 8
205 99 2
100 51 6
100 44 7
7440 41 7
111 44 4
108 60 1
117 81 7
75 27 4
74 83 9
85 68 7
88 85 7
7440 43 9
75 15 0
56 23 5
57 74 9
106 47 8
108 90 7
510 15 6
126 99 8
124 48 1
67 66 3
95 57 8
107 '05 1
Compound
Aeenaphthene
Acetone
Acetonitrile
Acecophenone
Acrolein
Acrylanide
Acrylonitrile
Aldrin
Aniline (Benzeneamine)
Antimony
Arani te
Arsenic
Barium
Benz (a) anthracene
Benzene
Benzidine
Benzo(a)pyrehe
Benzo (b ) f luoranthene
Benzyl alcohol
Benzyl chloride
Beryllium
Bis(2-chloroethyl)ether
Bis(2-chloroisopropyl ether)
Bis(2-ethylhexyl)pnthalate
Bromodichlorome thane
Bromoae thane
Butyl benzyl phthalate
2-sec-Butyl-4,6-dinitrophenol
(Dinoceb) ,
Cadmium
Carbon disulfide
Carbon tetrachloride
Chlordane
p-Chloroaniline
Chlorobenzene
Chlorobenzilate
2-Chloro-l,3-butadiene
(Chloroprene)
Chlorodibromone thane
Chloroform
2-Chlorophenol
3-Chloropropene (Allyl chloride)
HBL
fnif/n
2
4
2x10-*
4
SxlO'1
Treatment
Technique
2X10'6
6x10°
lx!0'2
1x1 0'3
5xlO'2
1
1X10*5
5x10°
2xlO'7
2x10'*
2xlO'5
IxlO1
2x10'*
IxlO'3
3xlO'5
3xlO'3
3x10**
5xlO'2
7
7x10°
SxlO'3
4
5x10°
2xlO'3
1X10'1
1X10'1
7X10*1
7xlO':
4x10'*
6x10°
2xlO'1
2x10°
Ref.
26
4
4
4
37
42
5
5
5
27
26
13
13
16
14
5
27
8
26
5
27
5
4
5
5
4
4
27
42
4
14
42
4
42
4
26
5
5
4
36
Solubility
lx!06
7.9x10'
l.SxlO'1
3.5x10*
5.7xlO-3
1.75X103 .
4.0xl02
1.2xlO-3
1.4xlO-2
4x10* (17 'C)
3.3x10*
1.02x10*
1.7xl03
4xlO-1
4.7xl03 (22*C)
l.OxlO3
2.9
5xlOl
2.94x10'
7.57x10*
5.6X10"1
3.9xl03
4.66xlOz
1x10*
3xl02 ,
4.4xl03(22*C)
8 . 2xl03
2.85xlO*(20'C)
IxlO2
Ref
6
6
6
15
2
15
6
6
2
6
6
6
6
6
15
6
6
6
11
22
18
10
6
6
6
6
24
6
1
1
22
6
15
15
-------
HEALTH-BASED LEVELS AND SOLUBILITIES
FOR CONSTITUENTS OF CONCERN IN DELISTING PETITIONS
July 1991
CAS No
7440 47 3
218 01 9
319 77 3
57 12 5
94 75 7
72 54 8
72 55 9
50 29 3
2303 16 4
53 70 3
96 12 8
74 95 3
84 74 2
95 50 1
106 46 7
91 94 1
75 71 8
75 34 3
107 06 2
75 35 4
156 59 2
156 60 5
75 09 2
120 83 2
78 87 5
542 75 6
60 57 1
64 66 2
56 53 1
60 51 5
119 90 4
119 93 7
57 97 6
105 67 9
131 11 3
99 65 0
51 28 5
121 14 2
117 84 0
123 91 1
Conreound
Chromium
Chrysene
Creiols
Cyanide
2,4-Dichlorophenoxyacetic
Acid (2,4-D)
DDD
DDE
DDT
Diallate
Dibenz (a , h) anthracene
l,2-Dibroao-3-chloropropane
Dibromome thane
Di-n-butyl phthalate
1 , 2 -Dichlorobenzene
1 ,4-Dichlorobenzene
3,3' -Dichlorobenridine
Dichlorodifluorome thane
1 , 1 -Dichloroe thane
1 , 2 -Dichloroe thane
1 , 1 -Dichloroethylene
cis -1,2 -Dichloroethylene
trans- 1 , 2 -Dichloroethylene
Dichlorome thane
2,4-Dichlorophenol
1 , 2 -Dichloropropane
1 , 3 -Dichloropropene
Dieldrin
Die thy 1 phthalate
Diethylstilbesterol
Dime cheat*
3,3' -Dimethoxybenzidine
3.3' -Dime thy Ibenzi dine
7,12-Dimethylbenz(a).
anthracene
2,4-Dinethylphenol
Dimethyl phthalate
1 , 3 -Dinitrobenzene
2 ,4-Dinitrophenol
Dinitrotoluene
Di-n-octyl phthalate
1,4-Dioxane
HBL
1X10*1
2x10'*
2
2X10'1
7xlO'2
1x10**
1x10'*
1x10'*
6x10'*
7xlO'7
2x10'*
4X10"1
4
6X10'1
7.5xlO'2
SxlO'5
7
4x10'*
SxlO'3
7xlO'3
7xlO*2
IxlO-1
SxlO'3
1X10'1
5xlO'3
2x10'*
2xlO'6
3x10^
7xlO'J
3x10*'
4xlO"8
lxlO'e
4X101
4xlO-»
7xlO'2
SxlO'f
7xlO-J
3xlO*s
Ref ^
42
8
4
27
42
5
5
5
26
8,17
42
4
4
42
14
5
4
26
14
14
42
42
27
4
42
5
5
4
26
4
26
26
20
4
26
4
4
5.21
26
5
Solubility
(Bg/1)
(in H,0
at 25*C}
l.BxlO*3
3.1x10*
8 . 9xl02
1X10"1
4xlO'2
5xlO"3
1.4X101
5.0x10'*
l.OxlO3
l.-3x!0*
l.SxlO1
l.OxlO2
7.9X101
4
2 . SxlO2
5.5xl03
8.52xl03
2.25xl03
3. SxlO3
6.3xl03
2.0x10*
4.6xl03
2.7xl03
2. SxlO3
1.95X10*1
8.96xl02
1.3x10*
2.5x10*
2xlOs
7xlO:
4.4xlO'3
5.9xl02
4.3xl03
4.7xl02
5.6xl03
1.32xl03
4.31xl03
Ref .
6
6
6
6
6
6
6
6
6
25
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
15
6
1,23
1,23
6
9
2
6
6
6
22
6
-------
HEALTH-BASED LEVELS AND SOLUBILITIES
FOR CONSTITUENTS OF CONCERN IN DELISTINC PETITIONS
July 1991
CAS No.
122 39 4
122 66 7
298 04 4
115 29 7
72 20 8
106 89 8
110 80 5"
100 41 4
60 29 7
106 93 4
97 63 2
62 50 0
52 85 7
206 44 0
86 73 7
16984 48 8
64 18 6
76 44 8
1024 57 3
118 74 1
87 68 3
77 47 4
67 72 1
70 30 4
319 84 6
319 85 7
193 39 5
78 83 1
78 59 1
143 50 0
7439 92 1
58 89 9
7439 97 6
126 98 7
67 56 1
72 43 5
74 87 3
56 49 3
78 93 3
108 10 1
Comnound
Diphenylamine
1 , 2 -Diphenylhydrazine
DIsulfoton
Endosulfan
Endrin
Epichlorohydrin
(l-Chloro-2 , 3-epoxypropane)
2-Ethoxy ethanol
Ethyl benzene
Ethyl ether
Ethylene dibromide
Ethyl nethacrylate
Ethyl methanesulfonate
Famphur
fluoranthene
Fluorene
Fluoride
Formic acid
Heptachlor
Heptaohlor epoxide (alpha,
beta, gamma isomers)
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Hexachlorophene
alpha -HCH
beta-HCH
Indeno (1 ,2.3, cd)pyrene
• Isobutanol
Isophorone
Kepone
.Lead
Lindane (gamma- HCH)
Mercury
Methacrylonitrile
Methanol
Methoxychlor
Methyl chloride
3 -Me thylcholanthrene
Methyl ethyl ketone
Methyl isobutyl ketone
HBL
(me/1}
9XW1
4xlO*s
IxlO"3
2x10°
2x10'*
Treatment
Technique
IxlO1
7xlO-1
2xlO:
5xlO's
IxlO-6
1x10°
1
1
4
7X101
4x10**
2x10'*
IxlO'3
4x10'*
5xlO'2
3x10°
lxW2
6xlO'e
2xlO's
2x10'*
IxlO1
9xlO"3
2xlO'6
1.5x10*'
2xl.0'v
2xlO"3
4xlO'3
2xlOl
4x10-*
3xlO'J
4xlO'8
2
2
Ref.
4
5
4
4
13
42
26
42
4
42
26
28
41
4
4
39
4
42
42
27
5
27
5
4
26
26
8
4
5
29
44
42
42
4
4
42
-26
30
4
4
Solubility
(mg/1)
(in H,0
at 25*n
5.76X101
1.84X103
2-SxlO1
5.3X10'1
2-SxlO'1
6.0x10*
IxlO5
1.52xl02
6.05x10*
4.3xlOJ
7xl02
3.69x10*
1.43X102 '
2.06xlO-1
1.69
IxlO6
l.BxlO'1
3.5xlO'J
6.0x10°
l.SxlO'1
siOxlO1
4x1 0'3
1.63
2.4xlO-1
5.3x10'*
7.6x10*
1.2x10*
7.6 (24»C)
7.8
2.5x10*
>lxl06
4xlO*2(.24'C)
6.5x10'
2.68xl05
1.91x10*
Ref.
6
6
24
22
22
6
1
6
12,2
6
1,6
6
15
6
6
6
6
6
6
6
6
6
6
6
6
6
3
15
15
6
15
1
24
6
6
2
-------
HEALTH-BASED LEVELS AND SOLUBILITIES
FOR CONSTITUENTS OF CONCERN IN DELISTINC PETITIONS
July 1991
CAS NO.
*•
80 62 6
298 00 0
91 20 3
91 59 8
7440 02 0
98 95 3
79 46 9
924 16 3
55 1C 5
62 75 9
156 10 5
621 64 7
10595 95 6
100 75 4
930 55 2
152 16 9
56 38 2
608 93 5
82 68 8
87 86 5
108 95 2
298 02 2
1336 36 3
23950 5S 5
129 00 0
110 86 1
94 59 7
7782 49 2
7440 22 4
57 24 9
100 42 5
95 94 3
. 630 20 6
79 34 5
127 18 4
58 90 2
3689 24 5
7440 28 0
108 88 3
95 80 7
Cenrooxrnd
Methyl aathacrylate
Methyl parathion
Naphthalene
2 -Naphthylanine
Nickel
Nitrobenzene
2-Nitropropane
N-Nitroso-di-n-butylamine
N-Nitrosodiethylamine
N-Nitrosodimethylaaine
N-Nitrosodiphenylamine
N-Nitrosodi-n-propylanine
N-Nitrosomethylethylanine
N-Nitrosopiperidine
Ni tros opyrro 1 i dine
Octane thy 1 pyrophosphoramide
Parathion
Pentachlorobenzene
Pentachloronitrobenzene
Pentachlorophenol
Phenol
Phorate
Polychlorinated biphenyls
Pronaaide
Pyrene
Pyridine
Safrole
Selenium
Silver
Strychnine and salts
Styrene
1 , 2 , 4 , 5 - Te trachlorobenzene
1,1,1 , 2-Tetraehloret thane
1.1,2 , 2 -Te trachloroethane
Tetrachloroethylene
2 , 3 ,4 , 6-Tetrachlorophenol
Tetraethyl dithiopyro-
phosphatc
Thallium
Toluene
Toluene-2,4-dianine
HBL
(aip/1)
9xlO'3
1x10-1
4xlO's
IxlO'1
2xlO'2
4xlO'6
6xlO'6
2xW7
7xlO*7
7xlO'3
SxlO*6
2xlO*e
8xlO-«
2xlO's
7xlO'2
2xlO'1
3xlO-2
IxlO'1
lx!0-J
2X101
7xlO'3
5x10**
3
1
4xlO'2
1x10'*
SxlO'2
SxlO'2
IxlO'2
IxlO'1
IxlO'2
1x10°
2x10'*
5x10°
1 • ."•
2xlO*2
2x10°
1
9xlO-s
Ref .
43,26
4
26
' 31
27
4
26
5
5
5
5
5
26
32
5
26
26
4
4
19
4
40
42
4
4
4
33
42
13
4
42
4
26
5
42
4
A
27
42
34
Solubility
(Bg/D
(in H,0
at 25*0
2-OxlO1
exio1
3.4xlOl
5.86xl02
1.9xl03
1.7x10*
6 . 7xl03
4.1xl05
2xl02
4.0xlOa
. 9.9xl03
2x10*
>lx!06
>lx!06
>lx!06
2.4xlOJ f20'C)
1.35x10^
7.11xlO-z
1.4X101
9.3x10*
5x10*
3.1xlO*2
Ixl0f
1.32X10'1
4x10*
l.SxlO3
1.56X102
3xl02
6
2.9xl03
2.9x10?
l.SxlO2
1x10*
SxlO1
5.35xl02
4.77x10*
Ref.
6
6
15
6
6
38
1,23
1,23
1
10
1
1
6
6
1
15
6
6
6
6
18
6
1
6
1
6
6
15
6
6
6
6
6
25
6
6
-------
HEALTH-BASED LEVELS AND SOLUBILITIES
FOR CONSTITUENTS OF CONCERN IN DELISTING PETITIONS
July 1991
CAS No.
823 40 5
95 53 4
106 49 0
8001 35 2
93 72 1
75 25 2
120 82 1
71 55 6
79 00 5
79 01 6
75 69 4
95 95 4
88 06 2
93 76 5
• 96 18 4
76 13 1
99 35 4
126 72 7
7440 62 2
75 01 4
1330 20 7
7440 66 6
ConrDOund
Toluene • 2 , 6 • diaaine
o-Toluidine
p-Toluidine
Toxaphene
2.4.5-TP (Silvex)
Tribronotne thane (Brooofoxn)
1,2,4-Trichlorobenzene
1 , 1 , 1-Trichloroethane
1,1, 2 -Trichloroethane
Trichloroethylene
Tr i chl oro f luor one thane
2,4, S-Trichlorophenol
2.4,6-Trichlorophenol
2 , 4 , 5-Trichlorophenoxy-
acetic acid (2,4,5-T)
1 , 2 , 3-Trichloropropane
l,1.2-Triehloro-1.2.2-
trifluoroe thane
cym • Tr ini tr obenzene
Tr is ( 2 , 3 - dibromopropyl )
phosphate
Vanadium
Vinyl chloride
Xylene (mixed)
Zinc
HBL
7
1x10'*
2x10'*
3xlO'3
SxlO'2
4xlO*3
9xlO*3
2X10*1
SxlO*3
5xlO'3
IxlO1
3xlO-J
4X10*1
2X10*1
IxlO3
2xlO*3
3x10**
2x10
2xlO*3
IxlO1
7
Ref.
7
26
26
42
42
5
27
14
27
14
4
A
5
4
4
4
4
35
26
14
42
26
Solubility
(mg/1)
(in H,0
at 25*0
1.3x10*
7xl02
7.4xl03 (21'C)
SxlO'1
1.4xl02
3.01xl03
3-OxlO1
l.SxlO3
4. SxlO3
l.lxlO3
l.lxlO3
1.19xl03
S.OxlO2
2.4xl02(30'C>
4xl03
IxlO1
3.5xlOz
. 1.2xl02
2.67xl03
1.98xl02
Ref.
1
1,23
15
6
2
6
6
6
6
6
6
6
6
2
1
6
2
6
6
6
-------
APPENDIX II
PROCEDURES FOR CONDUCTING RISK BASED CALCULATIONS
FOR DETERMINATION OF GROUND WATER CLEAN UP
ACTION LEVELS AT MIDCO I
Risk based calculations shall be conducted for each sample.
The calculation shall be the sum of the estimated risks
produced by each constituent in the sample.
The carcinogenic risk based calculation for each sample is
simply the summation of a lifetime averaged exposure rate via
ingestion of the ground water for each constituent times that
constituent's oral carcinogenic potency factor (slope factor),
plus the summation of a lifetime averaged exposure rate via
inhalation for each volatile organic compound times that
volatile organic compound's inhalation carcinogenic potency
factor (slope factor).
This is summarized in the following equation:
CRS =* 2 (OI),(OSF), + 2 (II),(ISF)f
01, = (3.09 x 10'2 1/kg/d) C,
II, = (9.74 x lO'f 1/kg/d) Cf
CR$ = Cumulative lifetime carcinogenic risk for a
sample
£ = Summation of the carcinogenic risk from each
constituent detected in the sample.
01, - Lifetime averaged exposure rate via ingestion
for constituent i
OSFj - Oral carcinogenic potency factor (or slope
factor) of constituent i. These are listed
in Table 2 of Appendix IV.
II, = Lifetime averaged exposure rate via inhalation
-------
for constituent i.
ISF = Inhalation carcinogenic potency factor (or
slope factor) of constituent i. These are
listed in Table 2 of Appendix IV.
3.09 x 10"2 1/kg/d = lifetime averaged ground water
ingestion rate based on the following assumptions:
The ground water intake averaged over 70 years
(25550 days) corresponding to children age 2-6,
with a body weight of 17 kg, and an ingestion
rate of 1 liter of ground water per day for 5
years, equal to 4.2 x 10'3 1/kg/d.
The ground water intake averaged over 70 years
corresponding to children age 7-12 with a body
weight of 29 kg, and an ingestion rate of 1
liter of ground water per day for 6 years, equal
to 3.0 x 10'3 1/kg/d.
The ground water intake averaged over 70 years
corresponding to adults, with a body weight of
70 kg, and an ingestion rate of 2 liters of
ground water per day for 58 years, equal to 23.7
x 10'3 1/kg/d.
(4.2 + 3.0 + 23.7) X 10'3 1/kg/d = 3.09 X 10'2
9.74 x 10"2 1/kg/d = lifetime averaged ground water
exposure rate via inhalation based on the
following assumptions:
Calculate the lifetime ground water inhalation
intake while bathing. In order to do this, it
is assumed that all subpopulations (adults,
children age -7-12 and children age 2-6) bathe
for 20 minutes each day and stay an additional
10 minutes inside the closed-door bathroom,
where the concentration in the air of the
compound volatilized from the ground water used
for bathing increases from zero to the actual
ground water concentration at the end of the
bathing period, and then decreases to zero
during the additional 10 minutes in the
bathroom. To account for this increase/decrease
in concentration, a factor of 0.38 is used in
the equation to calculate the intake. The
actual ground water concentration can then be
used to calculate the risk. Additional
assumptions include: (1) each bath will consume
-------
200 liters of water; (2) the volume of the
shower stall is 3 or; and (3) the volume of the
bathroom is 10 m3. Also, the volume of air
inhaled per hour is: 0.55 m3 for adults, 0.6 m3
for children age 7-12, and 0.49 m3 for children
age 2-6.
The inhalation intake can be calculated as:
0.38 [(200 1/3 m3) x (20 min/60 min/day) +
(200 1/10 m3) x (10 min/60 min/day)] x
[(0.55 m3 x 58 yrs)/(70 kg x 70 yrs) +
(0.60 m3 x 6 yrs)/(29 kg x 70 yrs) +
(0.49 m3 x 4 yrs)/(16 kg x 70 yrs)]
= 9.74 x 10'2 1/kg/d.
C. = Concentration of constituent i in the sample.
The cumulative chronic non-carcinogenic risk index is
calculated as follows:
NI = Z ((C,)(3.09 X 10'2 1/kg/d)/ORfD,) +
S ((C,-)(9.74 X 10'2 1/kg/d)/IRfD,-)
NIS '- Cumulative chronic non-carcinogenic risk
index.
Z = Summation of chronic non-carcinogenic risk for
all constituents detected in the sample that
affect the same target organ.
ORfOj- Oral reference dose of constituent i. The
reference doses for this Consent Decree are
listed in Table 2 of Appendix IV.
IRfD,= Inhalation reference dose of constituent i.
The reference doses for this Consent Decree
are listed in Table 2 of Appendix IV.
Compounds detected below the background concentrations listed
in the Table 1 of this Attachment will not be included in
either the carcinogenic or non-carcinogenic risk based
calculations.
The Primary Maximum Contaminant Levels (MCLs) are from 40 CFR
141. New primary MCLs will automatically be added to the
-------
4
ground water CALs when they are promulgated.
The Ambient Water Quality Criteria (AWQC) for protection of
aquatic life to be used in this Decree are listed in Table 2
of this Attachment. The ground water CALs for the AWQC are
calculated by multiplying the AWQC from Table 2 by 3.9.
The CAL can not be less than the background concentrations
listed in Table 1, nor be less than the analytical detection
limits. The analyses shall at least attain the quantification
limits necessary to evaluate attainment of the ground water
CALs. However, quantification limits below the lowest
practical quantification limits listed for each compound in
Appendix IX of 40 CFR 264 shall not be required. If only one
constituent is detected in a ground water sample that is
calculated to potentially cause a lifetime, incremental
carcinogenic risk of 1 x 10"5 or greater, and an MCL has been
promulgated for this constituent pursuant to 40 CFR 141, then
that constituent will not be used in either the carcinogenic
nor the non-carcinogenic risk calculations, and the CAL for
that constituent will be either the MCL or the AWQC times 3.9,
whichever is less.
-------
TABLE 1 OF APPENDIX II
MTEI lAOCUCUC CMCMTtATiaiS '
taM
«notic
Mill*
•EITLLIIM
CAM1IM
CUtOllUM (III)
CMtailUM (VI)
Of H*
no
uw
WNCANESE
MEIOffT
nictu
CELEV1UN
SllVEt
TMillUK
VAHA9IUN
ZUC
CTAV10E
VlKTl CHIMJ0E
CN;O(XTM«E
•tTHTlEKE CN1.QK10E
ACCTOK.E
CAI»» eituinoE
1,1-fiICKlOROeTNAHE
7UKi-i,2-p!CHtotoeri«EKE
CNlOSOFMM
ffS SUCL
•idee I Hideo 11
«.OQE«00 1.91{»01
1.1K*C2 1.C7S*£2
1.$0t-01
f.00f*00 7.SK*00
».00i»00 7.SOIHBO
2.55*01
3.«f*OJ 1.5SC*Oi
S.«OE*00
t.*at»03 *.*4E*02
2.50E-01
5.40E-01 1.2JE«OI
«.60E*00
4.S3E*00
1.47E-B3
l.OAE-01 1.$fl£-02
1.J2E»00 2.20E-00
1.SOE*00 1.ME-00
*.90E*00
1.60E-C1 4.10£»00
fS SUCL
ttmpard Hideo 1 Hideo 11
*-«ET«n..i-««TA*art
irTUCKOMfTMEVE
TOLUEHE
CTirnKKZEIS
KTLEKIS
MtKOc
II«(2-CKLatflETKTUfT««
iiS(2-emaioitviVTL)ETHEt
•E«Tt AiCOHOl
ciEsa
KITIOiEllZENE
1SOPNOIONE
2>>CIKETMTl^NENO;
•Eweic ACIC
2,*-PlCHJ.BtWMlO;.
IUPKTNAUNE
{•METNTLIUrilTMlEIIE
ACEVAPNTMEkE
*-«iiia*HEKO;
2,«-DlNlTIOTOlUENE
DIETNTlMTNALATE
ft-UMtHE
4-NITIMkUIHE
OI-*-Sum»KTMAlATE 3.00E-01
M-nntOSaBirNEVTLAMlliE 2.60E-01
PEKTACNLOKOPNEK9L
2-IUTANOME
1,1,1-TIICNlOtaCTHAIiE
A.OOE-C:
NEPTACNlOt E»WIOE
IINOAME
OlflCIli
EWSI1M
1.50E-03
1 Utl » 95 percent nap*' eonfitfene* Knit ef the tvirtgt Uckgi-cund pretrtf vtttr eor»c»ntr»tion »t etch *it(.
th« ft»tibility Stu^r ^or e»ch sit*.
*A11 values are given in ug/1.
POOR QUALITY
v ORIGINAL
-------
TABLE 2 OF 'APPENDIX II
MIDCO 1 AND II - HATER QUALITY CRITERIA TO BE MET IN THE GROUND UATES
MIOCO I
MIDCO II
Coopound
ARSENIC
SERTLLIUM
CADMIUM
CHROMIUM (III)
CHROMIUM (VI >
COPPER
I ROM
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
THALLIUM
ZINC
CYAN ICE
PENTACHLOROPHENOL
NEPTACHLOR EPOXIOE
D1ELDR1N
E NOR IN
PCSs
Surface Utter
Water Quality Criteria
(ug/o
4.80E-01
5.30£«00
1.20E»00-6.00£»00 H
2.20E*02-1.19£*03 H
1.10£*01
1.30E»01-7.30E*01 K
1 .OOE*03
3.50E*00-4.80E»01 H
1.20E-02
1.68E*02-9.57E«02 H
3.50E»01
1.20E-01
4.00E»01
3.42E»02-1.89E»03 H
5.20E+00
1.JO£«01 pH
3.60E-03
1.90E-03
2.30E-03
1.40E-02
woe
to be net
(us/ I)
1.87E*02
2.07J.01
*.6B£»00
e.SflE-02
«.29E»01
5.07E»01
3.90E«03
1.37E*01
4.6SE-02
6.55E->02
1.37E*02
4.6SE-01
1.56E»02
1.33E-OJ
2.03E*01
5.07E»01
1.48E-02
7.4U-03
8.97E-03
5.46£-02
Surface Water
Water Quality Criteria
(ug/U
4.80E-01
S.30E-00
2.90E»00-4.49E»00 H
5.5S£*02-8.68E»02 H
1.10E*01
3.33E»01-5.28E»01 H
1.00E-03
1.49E«01-2.96E»01 H
1.20E-02
4.iOE»02-6.94E-02 N
3.50E-01
1.20E-01
4.00E*01
8.7BE*02-1.37£»03 H
5.20E«00
3.80E-03
uoc
to be met
(ug/l)
1.73E»02
1.91E«01
1.ME-01
2.01E-03
3.96E»01
1.20E"02
3.60E-03
5.36E»01
4.32E-02
1.58E-03
1.26E»02
4.32E-01
1.44E«02
3.16E*03;
1.87E»01
1.37E-02
UOC • freshwater chronic water quality criteria for the protection of aquatic life; H • hardness
dependent, values shown are for the range of hardness present in surface water samples; pH • value it
pN dependent (pH « 7.8 used).
Reference: Quality Criteria for Water
1986. U.S. EPA. EPA 440/5-86-001.
May 1, 1986.
-------
APPENDIX III
PROCEDURES FOR DETERMINING
THE EXTENT OF TREATMENT FOR SOILS AND DEBRIS
AT MIDCO I
To define the extent of the treatment by S/S and/or by SVE
outside of the minimum area for treatment outlined in Figure 2,
samples shall be collected on a square grid with 60 foot centers.
The location of the initial grid point shall be determined by the
random number technique, and the rest of the grid points measured
from the initial point. The grid shall cover the whole soil
sample collection area shown in Figure 2 excluding the minimum
area for treatment. Split spoon samples shall be collected at
each grid point from 1-3 and 4-6 foot depths.
The following parameters shall be considered in determining
whether the Soil Treatment Action Levels (defined in Section
V.C.2) are exceeded at each sampling point:
METALS: total chromium, chromium (VI), lead, antimony,
nickel, barium, cadmium, selenium, copper, iron, zinc,
vanadium, manganese;
OTHER INORGANICS: arsenic, cyanide;
VOLATILE ORGANIC COMPOUNDS (VOCs): methylene chloride,
trichloroethylene, tetrachloroethylene, 2-butanone,
acetone, toluene, 1,1,1 trichoroethane, benzene,
xylene, ethyl benzene, methyl isobutyl ketone, 1,1-
dichloroethylene, 1,2 dichloroethylene, vinyl chloride;
ACID/BASE/NEUTRAL FRACTION: benzo(a)anthracene, chrysene,
benzo(b)fluoranthene, benzo(a)pyrene,
indeno(1,2,3)pyrene, dibenz(a,h)anthracene, bis(2-
ethylhexyl)phthalate, diethyl phthalate, di-n-butyl
phthalate, isophorone, phenol;
PESTICIDE/PCB FRACTION: 'chlordane, aldrin, dieldrin,
polychlorinated biphenyls.
For any of the grid sampling points that exceed the Soil
Treatment Action Levels, either:
(a) The entire area within the 60 foot square centered at the
grid point will be treated in accordance with Section V.c.2;
or
(b) Further sampling and treatment will be conducted as follows:
(1) The 60-foot square centered at the grid point shall be
subdivided into nine squares measuring 20 by 20 feet.
The center 20-foot square, where the grid point is
-------
located shall be treated in accordance with Section
V.C.2.
(2) Samples at 1-3 and 4-6 foot depth shall be collected at
the center of each of the eight surrounding 20 foot
squares. If any of these samples exceed the Soil
Treatment Action Levels, the entire area within these
20 foot squares shall be treated in accordance with
Section V.C.2.
(3) Samples at 1-3 and 4-6 foot depth shall be collected at
the center of each 20 foot square that is along side a
20-foot square determined to exceed the Soil Treatment
Action Levels based on the previous sampling. If any
of these samples exceed the Soil Treatment Action
Levels, the entire area within these squares shall be
treated in accordance with Section V.C.2.
(4) The process in (b)(3) above shall be repeated until
each 20 foot square along side a square containing a
sample that exceeds the Soil Treatment Action Levels,
has been sampled, even if this requires sampling of 20-
foot squares that are part of 60-foot squares whose .
center grid point sample results are less than the Soil
Treatment Action Levels.
-------
APPENDIX IV
PROCEDURES FOR CONDUCTING RISK BASED CALCULATIONS
FOR SOILS AND SEDIMENTS AT MIDCO I
Risk Calculations
Risk based calculations shall be conducted for each sample for
both carcinogenic and non-carcinogenic risks. The calculation
shall be the sun of the estimated risks produced by each
constituent detected in the sample for the ingest ion, dermal
contact, and inhalation routes of exposure using a residential
development scenario.
The carcinogenic risk based calculation for each exposure route
shall be the summation of the lifetime average exposure rate for
each constituent times that constituent's carcinogenic potency
factor (slope factor) . This is summarized by the following
equation:
CR. = 2 (OI)i(OSF)i + 2 (DDifDSF), + S
CR, = Cumulative lifetime carcinogenic risk for each
sample
2 = Summation of the carcinogenic risk for each
constituent detected in the sample
01; = Lifetime exposure rate to constituent i via
ingestion
DI; = Lifetime exposure rate to constituent i via dermal
contact
II; = Lifetime exposure rate to constituent i via
inhalation
OSFj = Oral slope factor or carcinogenic potency factor
(CPF) of constituent i
DSFj = Dermal slope factor or carcinogenic potency factor
of constituent i
-------
* Inhalation slope factor or carcinogenic potency
factor of constituent i
The non-carcinogenic risk based calculation for each exposure
route shall be the summation of the non-carcinogenic risk
indexes for each constituent. The non-carcinogenic risk index
is the ratio of the averaged exposure rate divided by the
reference dose. This is summarized by the following equation:
NI. = X (OCDIj)/(ORfD)j + S (DCDI)j/(DRfD)i + 2 (ICDI)j(IRfD)j
NI, «= Cumulative chronic non-carcinogenic risk index for
each sample
OCDI; = Chronic daily intake of constituent i for the inges-
tion route of exposure
DCDIj = Chronic daily intake of constituent i for the dermal
contact route of exposure
ICDI; = Chronic daily intake of constituent i for the
inhalation route of exposure
= Chronic oral reference dose
DRfDj * Chronic dermal reference dose
IRfD, = Chronic inhalation reference dose
Constituents that are not detected shall not be included in the
risk calculations. The chemical analyses shall at least attain
the quantitation limits necessary to evaluate attainment of
soil CALs. However, quantitation limits lower than the
detection limits listed in Table 1-7 of the Feasiblity Studies
for Hideo I and Hideo II will not be required. Compounds
detected below background concentrations shown in Table 1 shall
not be used in the risk calculations. No OSF, ISF, ORfD or
IRfD is presently available for lead. Therefore, the soil
-------
3
treatment action level for lead is set at 1000 ing/kg in the
soil, and the sediment/soil CAL is set at 500 mg/kg.
If NI, exceeds 5.0 for the STALs or 1.0 for the soil/sediment
CALs, the organ specific NI, shall be calculated in a manner
consistent with EPA guidance. Then the highest organ specific
NI, shall be used to evaluate whether the criteria for soil
treatment is or is not exceeded.
The procedures for the calculations for each exposure route are
summarized below:
FOR THE INGESTION ROUTE OF EXPOSURE;
CARCINOGENIC RISK CALCULATION
- Z (OI)a(OSF)i
= (2.34 mg/kg/d)(Cj)
= Cumulative lifetime carcinogenic risk for each
sample for the ingestion route of exposure
Olj = Lifetime exposure rate to constituent i for the
ingestion route of exposure
OSFj - Oral slope factor or carcinogenic potency factor
(CPF) of compound i. These are listed in Table
2. The CPFs in Table 2 are from the U.S. EPA
"Health Effects Assessment Summary Tables",
April 1989, OERR 9200.6-303-(89-2), except for
the carcinogenic polyaromatic hydrocarbons,
which are from the U.S. EPA Health Effects
Assessment Group.
2.34 mg/kg/d = lifetime averaged soil intake based on the
following assumptions:
- The soil intake averaged over 70 years (25550
days) corresponding to children age 2-6, with
-------
a body weight of 17 kg, and an ingestion rate
of 0.2 grams of soil per day for 5 years,
equal to 8.4 x lO"4 g/kg/d.
- The soil intake averaged over 25550 days
corresponding to children age 7-12, with a
body weight of 29 kg, and an ingestion rate
of 0.1 grams of soil per day for 6 years,
equal to 3.0 x 10"4 g/kg/d.
- The soil intake averaged over 25550 days
corresponding to adults, with a body weight
of 70 kg, and an ingestion rate of 0.1 grams
of soil per day for 58 years, equal to 12 x
10-1 g/kg/d.
(8.4 -i- 3.0 + 12) x 10-* g/kg/d x 10J mg/g
=2.34 mg/kg/d
= Concentration of constituent i in the sample in
milligrams contaminant per milligram soil.
NON-CARCINOGENIC RISK INDEX CALCULATION
NI.; = X (C)i(11.8 mg/kg/d)/ORfD;)
NI,j « Cumulative chronic non-carcinogenic risk index
for the ingestion route of exposure
Cj = Concentration of constituent i in the sample in
milligrams contaminant per milligram soil
11.8 mg/kg/d = Soil intake for children ages 2-6, based
on a bodyweight of 17 kg and an ingestion rate
of 0.2 grams.of soil per day for five years
ORfDj = Chronic oral reference dose. The oral
reference doses for this Decree are listed in
Table 2. The RfDs listed in Table 2 are from
the U.S. EPA "Health Effects Assessment Summary
Tables", April 1989, OERR 9200.6-303-(89-2)
-------
FOR THE DIRECT CONTACT ROUTE OF EXPOSURE:
CARCINOGENCIC RISK CALCULATION
- Z (DIMDSFJi
- (0^^(14.53 mg/kg/d)
= Cumulative lifetime carcinogenic risk for each
sample for the dermal contact route of exposure
DIj = Lifetime exposure rate to compound i for the
dermal contact route of exposure
C, = Concentration of constituent i in the sample in
milligrams contaminant per milligram soil
DSF, = Dermal slope factor or carcinogenic potency
factor (CPF) of constituent i. These are listed
in Table 2. The dermal CPFs in Table 2 were
adjusted from the oral CPFs by dividing the oral
CPF by the chemical-specific oral absorption
factor that represents the percentage of ingested
chemical that is actually absorbed. The
absorption factors are also listed in Table 2.
DFj = Desorption factor. This is a chemical-specific
value that takes into account the desorption of a
constituent from the soil matrix. The following
desorption factors shall be used: volatile
organic compounds = 0.25,* semivolatile organic
compounds = 0.10; inorganics - 0.01.
14.53 mg/kg/d = Lifetime soil to skin adherence based on
the following assumptions:
- The soil .adherence averaged over 70 years
(25550 days) corresponding to children age 2-6,
with a body weight of 17 kg, an exposed body
surface area of 3160 cm2, a soil-to skin
adherence factor of 0.9 mg/cm2 (Exposure Factors
Handbook, Technical Report, U.S. EPA, 1989,
Contract No. 68-02-4254) of soil per day, for
138 days per year, for 5 years, equal to 4.52
mg/kg/d. The exposed body surface area
includes arms, legs and hands (50th percentile,
children aged 3-4, from Exposure Factors
Handbook, 1989).
- The soil adherence averaged over 70 years
-------
(25550 days) corresponding to children age 7-
12, with a body weight of 29 kg, an exposed
body surface area of 4970 en2, a soil-to skin
adherence factor of 0.9 mg/cm2 of soil per
day, for 138 days per year, for 6 years,
equal to 5.00 mg/kg/d. The exposed body
surface area includes arms, legs and hands
(50th percentile, children aged 9-10 from
Exposure Factors Handbook, 1989).
The soil adherence averaged over 70 years
(25550 days) corresponding to adults, with a
body weight of 70 kg, an exposed body surface
area of 3120 cm2, a soil-to skin adherence
factor of 0.9 mg/cm2 of soil per day, for 55
days per year, for 58 years equal to 5.01
mg/kg/d. The exposed body surface area
includes arms and hands (50th percentile
adults from Exposure Factors Handbook, 1989).
NON-CARCINOGENIC RISK INDEX CALCULATION
NI* - £ (C),(DP),(63.25 mg/kg/d) / (DRfDs)
NI,,, = Cumulative chronic non-carcinogenic index for
the direct contact route of exposure
q = Concentration of constituent i in the sample in
milligrams contaminant per milligram soil
DF; = Desorption factor. Use definition previously
provided for the carcinogenic risk calculation.
63.25 mg/kg/d = The soil adherence corresponding to
children age 2-6, with a body weight of 17 kg,
an exposed body surface area of 3160 cm2, a
soil-to skin adherence factor of 0.9 mg/cm2 of
soil per day, for 138 days per year, for 5
years.
DRfD| = Chronic dermal reference dose. The chronic
dermal reference doses for this Decree are
listed in Table 2. The chronic dermal reference
doses listed in Table 2 were adjusted from the
oral reference doses by multiplying the oral
reference doses by the chemical-specific oral
. absorption factor that represents the percentage
of ingested chemical that is actually absorbed.
The oral absorption factors are also listed in
Table 2.
-------
FOR THE INHALATION ROUTE OF EXPOSURE;
CARCINOGENIC RISK CALCULATION
= Z
= Cumulative carcinogenic risk for each sample for
the inhalation route of exposure
= Lifetime exposure rate to constituent i for the
inhalation route of exposure
= Inhalation slope factor or carcinogenic potency
factor (CPF) for constituent i. The inhalation
CPFs are listed in Table 2 and are from: U.S.
EPA, 1989, Health Effects Summary Tables, OERR
9200.6-303-(89-2) .
C; = Concentration of constituent i in the sample in
milligrams contaminant per milligram soil
DJ = Diffusion coefficient of constituent i in the
air, in cm2/ sec
VPj = Vapor pressure of constituent i, in mm Hg
MW; = Molecular weight of constituent i, in g/mole
0.033 = fINRI (ET) fEFl fED) m fP4^ riOOO mo/Pi
(BW) (AT) (h) (U) (W) (L) (R) (T)
INR = Inhalation rate in m'/hour: 0.76 from 1-6
years; 0.8.9 from 7-12 years; 0.83 for adults
ET * Exposure time in hours/day: 21.1 from 1-6
years; 18.3 from 7-12 years; 21.1 for adults
EF - Exposure frequency in days/year: 350 for all
age groups
ED « Exposure duration in years: 6 years from 1-6
years; 6 years from 7-12 years; and 58 years
for adults
A = 1 E+6 cm2 (a box 1 meter wide and 100 meters
long)
P = Total soil porosity: 0.35
-------
8
BW = Body weight in kg.: 17 kg from 1-6 year; 29
kg. from 6-12 years; and 70 kg adult
AT = Averaging time: 25550 days (365 days/year X
70 years)
h = Mixing height: 1.63 meters
w = Mixing width: 1 meter
u = Wind speed: 2.4 meters/sec.
L = Effective depth of soil cover: 30 cm.
R = Gas constant: 62,361 mm Hg/gmole/°K
T = Temperature: 290 °K
NON-CARCINOGENIC RISK INDEX CALCULATION
HI = I
NI,j = Cumulative chronic non-carcinogenic index for
the inhalation route of exposure
Cj - Concentration of constituent i in the sample in
milligrams contaminant per milligram soil
Dj; VPj, and MWt are as defined above
0.0938 = fINR) fETl fEFl (Em (Al (&") flOOO mo/cM
(BW) (AT) (h) (U) (W) (L) (R) (T)
INR = Inhalation rate in m3/hour: 0.76 for 1-6 year
olds
ET = Exposure time in hours /day: 21.1 for 1-6
year olds
ED = Exposure duration in years: 6 years
BW = Body weight in kg. : 17 kg for 1-6 year olds
AT - Averaging time: 2190 days (365 days/year X 6
years)
A, P, EF, P, h, w, u, L, R, and T are as defined
above
-------
9
Inhalation reference dose for constituent i. The
inhalation CPFs are listed in Table 2 and are
from: U.S. EPA, 1989, Health Effects Summary
Tables, OERR 9200.6-303-(89-2).
-------
TABLE 1 OF APPEMDIX IV
MIOCO I AND II - BACKGROUND SOIL CONCENTRATIONS *
COMPOUND
ALUMINUM
ANTIMONY
ARSENIC
BARIUM
BERYLLIUM
CADMIUM
CALCIUM
CHROMIUM (III)
CHROMIUM (VI)
COBALT
COPPER
IRON
LEAD
MAGNESIUM
MANGANESE
MERCURY
NICKEL
POTASSIUM
SELENIUM
SILVER
SODIUM
THALLIUM
TIN
VANADIUM
ZINC
CYANIDE
METHYLENE CHLORIDE
ACETONE
1,1-DICHLOROETKANE
TRAN5-1,2-OICHLORO£THENE
CHLOROFORM
95Z UCL
< usAg)
8.175.837
1.290
14,014
80,492
0
2,769
10,662,779
19.260
19,260
4,197
48,876
13,673,722
145,843
3,386,934
117,133
28S
17.J48
1,002,938
0
U7
81,517
1,477
1,581
20,553
312,974
0
9.4
13.9
0
0
0
COMPOUND
1.2-D1CHLOROETHANE
2-BUTANONE
1,1,1-TRICMLOROETHANE
1 , 1 ,2,2-TETRACHLOROETHANE
TRICHLOROETHENE
BENZENE
2-HEXANONE
4-METHYL-2-PENTANONE
TETRACHLOROETHENE
TOLUENE
CHIOROBENZENE
ETHYLBENZENE
STYRENE
TOTAL XYLENES
PHENOL
l.t-OlCHLOROBENZENE
2-NETHYLPHEHOL
4-METHYLPHENOL
CRESOL
NITROBENZENE
N-NITROSOOIPROPYLAMIHE
ISOPHORONE
2,4-OIMETHYLPHENOL
BENZOIC ACID
2,4-OICHLOROPHENOL
NAPHTHALENE
4-CHLORO-3-METHYLPHEHOL
2-METHYLNAPHTHALENE
ACENAPHTHYLENE
ACENAPHTHENE
DIBEN20FURAN
9SX UCL
(ug/kg)
0
6.7
0
0
0
0
0
0
0
2.0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
COMPOUND
DIETHYLPHTHALATE
FLUORENE
N-NITROSCOIPHENYLANINE
PENTACNLOROPHENOL
PHENANTHRENE
ANTHRACENE
DI-N-BUTYLPHTHALATE
FLUORANTHENE
PYRENE
BUTYLBEXZTLPHTHALATE
BENZO(A)ANTHRACENE
BIS(2-ETHYLKEXYL)PHTHALATE
CHRYSENE
DI-N-OCTYLPHTHALATE
BENZO(B)FLUORANTHENE
SENZO(K)FLUORANTHEKE -
8EMZO(A)PYRENE
INDENOC1,2,3-CO)PYRENE
DIBENZ(A,H>ANTHRACEKE
BENZO(G,H.I)PERYLENE
ALDRIN
DIELDRIN
ENORIN
4,4' -ODD
*,4'-DDT
CHLOROANE
AROCL08-1242
AROCLOR-1248
AROCLOR-1254
AROCLOR-1260
4,4-DOE
95S UCL
(ug/kg)
27.1
0
0
0
131
0
0
255
248
112
158
985
238
36.4
241
. 154
' 137
103
0
108
0
0
0
29.5
127
4,098
0
0
0
0
44.8
951 UCL • 95 percent ifper confidence limit of tht ivertgc tackgrovnd soil concentration*.
Study (both tites have the same soil background concentrations).
From the Feasibility
-------
TABLE 2 OF APPENDIX* IV i
CHEMICAL SPECIFIC RISK FACTORS
CHEMICAL
antimony
arsenic
barium
beryllium
cadmium
chromium(IIl)
chromium(Vl)
manganese
mercury
nickel
selenium
thallium
tin
vanadium
tine
cyanide
methylene chloride
acetone
1,1-dichloroethane
1 ,1 -dichloroethen*
chloroform
1,2-dichlorocthan*
2-butanone
l,l,l-trichloroeth»ne
carbon tetrachloride
1,1,2,2-tetraehloroethane
1,2-dichloropropan*
trichloroethene
1,1,2-trichlorotthane
bentene
4 -methyl- 2-pentanone
CPF-oral
(mg/kg/d)-1
NA
i.rsE+oo
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
7.SOE-OS
NA
NA
6.00E-01
6.10E-OS
9.10E-OJ
NA
NA
l.SOE-01
2.00E-01
6.80E-02
1.10E-02
J.70E-02
2.90E-02
NA
Chronic
Oral
RID
(mg/kg/d)
4.00E-04
l.OOE-03
5.00E-OJ
5.00E-OS
l.OOE-03
l.OOE+00
5.00E-03
2.00E-01
3.00E-04
2.00E-02
3.00E-03
7.00E-05
6.00E-01
7.00E-03
2.00E-01
2.00E-02
6.00E-02
l.OOE-01
l.OOE-01
9OOE-03
l.OOE-02
NA
5.00E-02
B.OOE-Ol
r.ooE-04
NA
NA
NA
4.00E-03
NA
S.OOE-02
Inhalation
CPF
(mg/kg/d)'1
NA
S.OOE+01
NA
8.40E+00
6.10E+00
NA
4.10E+00
NA
NA
8.40E-01
NA
NA
NA
NA
NA
NA
1.40E-02
NA
NA
I.20E+00
8.10E-02
~ 9.10E-02
NA
NA
1.30E-01
2.00E-01
NA.
1.30E-02
S.70E-02
2.90E-02
NA
Chronic
Inhalation
Rfl>
(mg/kg/d)
NA
NA
l.OOE-04
NA
NA
NA
NA
3.00E-04
NA
NA
l.OOE-03
NA
NA
NA
NA
NA
S.OOE+00
NA
l.OOE-01
NA
NA
NA
9.00E-02
3.00E-01
NA
NA
NA
NA
NA
NA
NA
Oral
Absorption
Factor
o.os
0.98
0.10
0.001
0.06
0.01
0.05
0.05
0.15
0.05
0.60
0.05
O.OS
O.OS
O.SO
0.45
1. 00
0.90
0.70
0.93
1.00
1.00
0.90
0.90
0.80
0.90
0.90
0.9S
0.90
1.00
0.90
Dermal
CPF*
(mg/kg/d)'1
NA
1.79E+00
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
7.50E-03
NA
NA
6.45E-01
6.10E-03
9.10E-02
NA
NA
1.63E-01
2.22E-01
6.67E-02
1.16E-02
6.33E-02
2.90E-02
NA
Chronic
Dermal
RfD
(mg/kg/d)
2.00E-05
9.80E-04
S.OOE-03
5.00E-06
6.00E-05
l.OOE-02
2.50E-04
l.OOE-02
4.50E-05
l.OOE-03
1.80E-03
3'.SOE-06
3.00E-02
3.SOE-04
l.OOE-01
9.00E-03
6.00E-02
9.00E-02
7.00E-02
9.30E-03
l.OOE-02
NA
4.SOE-02
8.10E-02
S.60E-04
NA
NA
NA
3.60E-03
NA
4.50E-02
-------
CHEMICAL SPECIFIC RISK FACTORS
CHEMICAL
tetrachloroethine
toluene
chlorobetuene
ethylbencene
xylenei
phenol
1 .4- dichlorobentene
1 ,2- dichlorobentene
cresol
nitrobentene
isophorone
benioic acid
2,4-dichlorophenol
1,2,4-trichlorobenienc
napthalene
4-chloroaniline
diethylphthalate
N-nitroiodipbenylamint
pentachlorophenol
di-N-butylphthalate
bentidin*
butylbentylphthalate
bento(a)anthracene
bii(2-«thylhcxl)phthaJat*
chryitn*
benio(b)fluoranlhene
b«nto(a)pyrcn«
indtno(l,2,S-ed)pyrtne
dibent(a,h)anthracene
aldrin
dieldrin
endrin
CPF-oral
(mg/ki/d)'1
5.10E-02
NA
NA
NA
NA
NA
2.40E-02
NA
NA
NA
4.10E-03
NA
NA
NA
NA
S.SOE-02
NA
4.90E-03
NA
NA
2.30E+02
NA
1.15E-01
1.40E-02
1.15E-01
3.4SE+00
1.15E+01
1.15E-01
1.1SE+01
1.70E+01
1.60E+01
NA
Chronic
Oral
Rfl>
(mj/kj/d)
l.OOE-02
3.00E-01
3.00E-02
l.OOE-01
2.00E+00
6.00E-01
NA
4.00E-01
S.OOE-02
S.OOE-04
1.50E-01
4.00E+00
3.00E-03
2.00E-02
4.00E-01
4.00E-03
8.00E-01
NA
300E-OJ
l.OOE-OI
3.00E-03
2.00E-01
NA
2.00E-02
NA
NA
NA
NA
NA
3.00E-OS
5.00E-05
S.OOE-04
Inhalation
OFF
(mj/ki/d)'1
3.30E-03
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.30E+02
NA
- NA
NA
NA
NA
NA
NA
NA
i.roE+oi
1.60E+01
NA
Chronic
Inhalation
RID
(m«/kj/d)
NA
l.OOE+00
S.OOE-03
NA
4.00E-01
NA
7.00E-01
4.00E-02
NA
6.00E-04
NA
NA
NA
3.00E-03
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Oral
Absorption
Factor
0.90
1.00
0.31
0.82
1.00
0.90
1.00
0.90
0.90
0.90
0.90
0.40
0.90
0.90
1.00
0.90
0.15
0.90
0.90
0.8S
0.90
0.15
0.50
0.15
O.SO
0.15
0.50
O.SO
0.50
0.50
0.50
0.50
Dermal
CPF'
(mg/kt/d)-1
5.67E-02
NA
NA
NA
NA
NA
2.40E-02
NA
NA
NA
4.S6E-03
NA
NA
NA
NA
3.89E-02
NA
S.44E-03
NA
NA
:.56E*02
NA
2.30E-01
9.33E-02
2.SOE-01
6.90E+00
2.30E+01
2.SOE-01
2.30E+01
3.40E+01
3.20E+01
NA
Chronic
Dtrmal
IUD
(mg/ki/d)
S.OOE-03
S.OOE-01
9.30E-03
8.20E-02
2.00E+00
S.40E-01
NA
3.60E-01
4.50E-02
4.SOE-04
1.35E-01
1.60E+00
2.70E-OS
1.80E-02
4.00E-01
3.60E-03
1.20E-01
NA
2.70E-02
8.50E-02
2.70E-03
3.00E-02
NA
3.00E-03
NA
NA
NA
NA
NA
1.50E-05
2.SOE-05
1.50E-04
-------
CHEMICAL SPECIFIC RISK FACTORS
CHEMICAL
4,4'-DDT
chlordane
aroclor-1242
araclor-1248
aroclor-1254
araclor-1260
PCBi
CPF-oral
(mg/kg/d)-1
3.40E-01
1.30E+00
7.70E+00
7.70E+00
7.70E+00
7.70E1-00
7.70E+00
Chronic
Oral
RfD
(mg/kg/d)
S.OOE-04
S.OOE-05
NA
NA
NA
NA
NA
Inhalation
CPF
(mg/kg/d)'1
S.40E-01
l.SOE+00
NA
NA
NA
NA
NA
Chronic
Inhalation
RfD
(mf/kg/d)
NA
NA
NA
NA
NA
NA
NA
Oral
Absorption
Factor
0.50
O.SO
0.50
0.50
0.50
0.50
0.9S
Dtrmal
CPF'
(mg/kg/d)'1
6.80E-01
2.60E+00
1.54E+01
1.54E+01
1.S4E+01
1.54E+01
8.11E+00
Chronic
Dtrmal
RfD
(mg/kj/d)
2.50E-04
2.50E-05
NA
NA
NA
NA
NA
NA Not Available
CPF Carcinogenic Potency Factor
RfD Reference Dote
* Dermal risk factors are calculated as follows:
Oral CPF
oral absorption factor
Dermal CPF
Oral RfD * Oral Absorption Factor - Dermal RfD
-------
APPENDIX V
PROCEDURE FOR CONDUCTING RISK
CALCULATIONS FOR AIR EMISSIONS
The carcinogenic risk calculations shall be the summation of a
lifetime averaged exposure rate for each constituent times that
constituent's inhalation carcinogenic potency factor. This is
summarized in the following equation:
CR = S (II), (ISF),
CR = Cumulative lifetime carcinogenic risk.
2 = Summation of the carcinogenic risk of each
constituent in the air emission.
II, = Lifetime averaged exposure rate to compound i.
More information from the design will be needed
to determine II ( for each process or combination
of processes. However, the values for INR, ET,
EF, ED, BW, and AT from Appenidix IV shall be
used for exposures to residents. In addition
IR for workers shall be 1.3 cubic meters per
hour.
ISFj = Inhalation carcinogenic potency factor (or
slope factor) for compound i. The ISFs are
listed in Table 2 of Appenidix IV.
The chronic non-carcinogenic risk index is calculated as follows:
NI =2 (II)i/RfDi
NI = Cumulative .chronic non-carcinogenic index
2 = Summation of chronic non-carcinogenic risk
for all constituents affecting the same
target organ
' ilj = Chronic exposure rate of constituent i. More
process specific information is needed to
calculate this number.
RfD, = Inhalation reference dose of constituent i.
The RfD; are listed in Table 2 of Appenidix
IV.
------- |