United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROO/R07-87/008
September 1987
Superfund
Record of Decision:
Minker Stout/Stout, MO
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TECHNICAL REPORT DATA
(Pleate rtad Instruction} on tht revtnt be/ore completing}'
1. HEPOHTNO.
^A/ROD/ROT-ST/OOS
2.
3. RECIPIENT'S ACCESSION NO.
iTLE AND SUBTITLE
sUPERFUND RECORD OF DECISION
Minker/Stout/Romaine Creek - Stout Portion, MO
Third Remedial Action
5. REPORT DATE
September 28, 1987
6. PERFORMING ORGANIZATION CODE
7. AUTMOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
CONTHACT/GHANT NO.
12. SPONSORING AGENCY NAME AND AOORESS
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
Final ROD Report
1*. SPONSORING AGENCY CODE
800/00
IS. SUPPLEMENTARY NOTES
16. ABSTRACT
The Stout portion of the Minker/Stout/Romaine Creek site is located on West Swalier
Road near Imperial, Missouri, approximately 20 miles southwest of St. Louis. The Stout
portion consists of five private properties, three of which have been purchased by EPA
•3 part of a permanent relocation of area residents. In the late 1960s and early 1970s,
southwest Missouri.chemical plant producing 2,4,5-T and hexachlorophene contracted a
-aste oil reclaimer to remove process residues. These residues, contaminated with
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), were mixed with waste oils and sprayed as a
dust suppressant on a nearby horse-arena'.- In-March of 1983, the horse arena owner had
the contaminated soils removed to various portions of the Minker/Stout/Romaine Creek
site. Approximately 700 yd3 of this soil was used as fill in the Stout area, near two
mobile home pads. In 1982, EPA sampling revealed high concentrations of TCDD in onsite
soils. Later that year, three of the five properties making up the Stout portion were
purchased by EPA and the residents were permanently relocated. No removal of
contaminated soil has been performed to date. The primary contaminant of concern is
dioxin.
The selected interim remedial measure for the Stout portion of this site includes:
excavation and temporary onsite storage of soils contaminated with greater than 1 ug/kg
TCDD (interim storage will be utilized until a final dioxin management option can be
(See Attached Sheet)
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lOENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Record of Decision
Minker/Stout/Romaine Creek -
Stout Portion, MO
Third Remedial Action
Contaminated Media: soil
•y contaminants: dioxin
ISTRIBUTION STATEMENT
19. SECURITY CLASS iTIni Report/
None
21. NO. OF PAGES
17
JO. SECURITY CLASS iTMs pagti
None
22. PRICE
EPA
2730.1 (R«*. 4-77) »H«VIOUS COITION is OMOLCTC
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EPA/ROD/R07-87/008
Minker/Stout/Romaine Creek - Stout Portion, MO
Third Remedial Action
16. ABSTRACT (continued)
selected); and backfilling and revegetation of the excavated areas with clean
materials. The estimated present worth cost for this remedial action is $5,817,000
£7,018,000 with annual O&M of $6,000.
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5 Record of Decision
Operable Unit Remedial Alternative Selection
SITE: Stout Portion of Minker/Stout/Romaine Creek NPL Site
DOCUMENTS REVIEWED
I am basing my decision primarily on the following documents describing
the analysis or cost-effectiveness of operable unit remedial alternatives for
interim management of dioxin-contaminated materials at the Stout portion of
the Minker/Stout/Romaine Creek NPL site. Additional documents considered are
included in the Administrative Record for this action.
- Operable Unit Feasibility Study - Stout Portion of the
Minker/Stout/Romaine Creek Site, July 8, 1987.
- Summary of Remedial Alternative Selection - Stout Portion
of the Minker/Stout/Romaine Creek Site.
- Responsiveness Summary - Operable Unit Remedial Actions for the
Stout and Romaine Creek portions of the Minker/Stout/Romaine Creek Site.
- Federal Position Statement on Dioxin in Missouri, Centers for Disease
Control, December 7, 1982.
- Public Health Advisory for the Minker/Stout Sites, Centers for Disease
Control, March 17, 1983.
- Addendum to March 17 "Public Health Advisory for the Minker/Stout Sites," .
Centers for Disease Control, April 7, 1983.
- Health Implications of 2,3,7,8-tetrachlorodibenzodioxin (TCDO) Contamination
of Residential Soil, Kimbrough, R.D., et al., Journal of Toxicity and
Environmental Health, 14:47-93, 1984.
DESCRIPTION OF SELECTED REMEDY
The selected operable unit remedial action alternative involves the
excavation of soil at the Stout area contaminated with 2,3,7,8 tetrachlorodibenzo-
p-dioxin (TCDD) at levels exceeding one part per billion (1 ppb). Contaminated
materials will be excavated until a residual TCDD concentration of less
than 1 ppb remains. Excavation will not continue beyond a depth of four
feet, or once solid bedrock is encountered. Excavated materials will be
containerized and placed in temporary .onsite storage untfl a final management
alternative is implemented. Storage structures for the excavated material
will be constructed on the former Edwards property adjacent to Romaine Creek.
The Baczynski property on West Swaller Road will be considered only as a
contingency storaye location if an adequate amount of suitable land does
not exist on the former Edwards property for storage of contaminated
materials from the Stout area and Romaine Creek. The storage structures
will be designed and constructed in accordance with the substantive
requirements for hazardous waste storage facilities under the Resource
Conservation and Recovery Act, as amended. Following removal of contaminated
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material from the Stout area, excavated areas will be backfilled to original
grade with clean material and revegetated.
DECLARATIONS
Consistent with the Comprehensive Environmental Response, Compensation,
and Liability Act of 198U (CERCLA), and the National Contingency Plan
(40 CFR Part 300), I have determined that excavation and interim onsite
storage of TCUD-contaminated materials at the Stout portion of the
Minker/Scout/Romaine Creek site is cost-effective, consistent with a
permanent remedy, and provides adequate protection of public health,
welfare* and the environment. The remedy selection procedure and selected
alternative comply with provisions of the Superfund Amendments and fteauthorization
Act of 1986. The State of Missouri has been consulted and concurs with
the selected remedy.
I have also determined that the action being taken is appropriate when
balanced against the availability of Trust Fund monies for use at other
sites. The selected operable unit remedial alternative is consistent with
Section 30u.68(c) of the National Contingency Plan and is a component of a
total remedial action which will attain all applicable or relevant and
appropriate requirements for the protection of public health and environment.
_
Date ARegfbn*! Administr'ator /
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
STOUT PORTION OF THE MINKER/STUUT/ROMAINE CREEK SITE
JEFFERSON COUNTY, MISSOURI
The purpose of this document is to state the interim remedy that the
Environmental Protection Agency (EPA) has selected to implement at the
Stout portion of the Minker/Stout/ Romaine Creek site. This document
will also include a brief analysis of remedial action alternatives which
have been evaluated leading to the Ayency's decision of remedy preference.
An operable unit is defined as a discrete part of an entire response
action for an uncontrolled hazardous waste site which functions to decrease
a release, threat of release, or pathway of exposure of hazardous
substances. Operaole units must be consistent"with the final remedy for
a site and must be cost-effective according to the provisions of SARA.
It is assumed in this document that the final remedial action at the
Stout area will involve offsite management, which will require eventual
excavation of contaminated soil and sediments.
SITE DESCRIPTION
The Stout portion of the Minker/Stout/Romaine Creek hazardous waste site
is located in Jefferson County, Missouri, approximately 20 miles southwest
of St. Louis. The Stout area is on West Swaller Road near the top of a
steeply sloping hillside in an unincorporated, low-density residential
area near Imperial, Missouri.
The Stout area is composed of five properties: the Vogt property, the
Sutton property, and the former Hutchinson, Cisco, and Baczynski
properties. These properties are collectively referred to as the Stout
area because the TCDD-contaminated fill was originally placed at the site
by a local contractor of that name. The Hutchinson, Cisco, and Baczynski
properties have been purchased during a permanent relocation implemented in
iyb3. There are unoccupied residences on the former Hutchinson, Cisco,
and Baczynski properties.
An unnamed intermittent creek lies at the bottom of the slope below the Stout
area; This creek is approximately l/2-mile-.long and flows primarily duriny
periods of heavy precipitation and runoff. It drains into Rock Creek, a
minor tributary of the Mississippi River.
The contamination occurs on most of the Sutton property and on those portions
of the Vogt and Hutchinson properties that are immediately adjacent to the
Sutton property. A fill area is located on the Sutton property which provides
a level surface for two mobile home pads. Uue to the detection of contamination
at depth, it was initially speculated that the contaminated soil was used with
other soil for construction of the fill area, and that the contamination was
potentially distributed throughout the fill. Subsequent investigations have
suggested, however, that the mobile home pads were in place at the time the
contaminated soil was brought to the Stout area. This would limit the
contamination to surficial soils and result in a reduced volume of material
-equiring remediation.
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SITE HISTORY
Tne Minker/Stou-t/Romaine Creek site was placed on the Environmental
Protection Agency's National Priorities List (NPL) of uncontrolled
hazardous waste sites in 1983 because 2,3,7,8 tetrachlorodibenzo-p-dioxin
(TCOU) was detected in the soil at concentrations exceeding a level of
concern for the protection of public health. A historical investigation
of the situation indicated the contaminants originated from a chemical
plant in southwest Missouri, which produced hexachlorophene and 2,4,5-T
in the late 196u's and early 197u's.
In 1971, a Missouri waste oil reclaimer was contracted to remove process
residues contaminated with TCDD from a tank located at the southwest Missouri
plant., This material was subsequently mixed with waste oil and sprayed as a
dust suppressant on the Bubbling Springs Horse Arena near Imperial > Missouri.
In March of 1973, the horse arena owner contracted with a local hauler
for the removal of the contaminated soil from the arena. The arena was
excavated and material was deposited at several locations which now constitute
the individual portions of the Minker/Stout/Romaine Creek site. Approximately
700 cubic yards of this excavated soil were deposited at the Stout area
near the two mobile home pads.
Previous Investigations of contamination at the Stout area have consisted
of soil sampling in May, October, and November 19a2, February through May
1983, and March 1986. Analysis of samples for priority pollutants and
TCDD has indicated that other contaminants are not present at levels of
concern, and that TCDD fs present at levels requiring remediation to
assure protection of human health and the environment.
Initial sampling in May 1982 detected TCOD concentrations up to 21 ppb. The
sampling performed in October and November of ly82 involved collection of
samples at various depths up to 20 feet. Detected TCDD concentrations
ranged up to 22.2 ppb. One sample showed a level of 5.8 ppb at a depth
of 20 feet, subsurface contamination was only detected in one of nine
boring locations, however, so the vertical distribution of contamination
remains uncertain. It has been the Agency's experience since the collection
of these samples that cross contamination can result in a false indication
of contamination at depth in soil core samples unless special precautions
are taken.
In February and March 1983, samples were collected from a 20-foot grid
pattern over the fill area. Contaminant levels as high as 241 ppb were
detected. This sampling also indicated that contamination had migrated
into the unnamed tributary to Rock Creek below the Stout area.
In April and May of 1983, extensive sampling was performed in the vicinity
of the Stout area. This sampling confirmed that contamination was limited
to the Stout area and approximately 800 feet along the unnamed intermittent
stream. TCDD concentrations exceeding 1 ppb in the intermittent stream
have been detected only directly below the Stout area. A maximum TCOD
concentration of 11 .ppb has been detected in this portion of the stream.
TGOD concentrations in the stream are reduced to less than 1 ppb within
100 feet downgradient of this area.
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In March 1986, the Stout area was sampled using a statistically-based
procedure wnich determined the maximum expected TCOO concentration within
discrete areas of the site to the 9b percent confidence level. This
procedure has been reviewed and approved by federal and state health and
environmental agencies ana has been utilized since 1984 during removal
actions involving the cleanup of TCDO-contaminated soil at sites in
Missouri. The areal extent of contamination exceeding 1 ppo wnich was
determined by this procedure is approximately 1.1 acres immediately
surrounding the mobile home pads north of West Swaller Road and areas
immediately downgradient.
Remedial actions performed to date at the Stout area have involved the
permanent relocation of three residences following discovery of TCDU
contamination in 1982. These three properties were purchased using CERCLA
remedial autnority and funding. Titles to the properties have been
transferred to the State of Missouri. A fence was constructed around the
contaminated portion of the area in 1987 to restrict access to contaminated
soils. No removal of contaminated soil has been performed to date.
COMMUNITY RELATIONS HISTORY
Section 117 of SARA provides that notice must be published and a brief
analysis of the proposed plan be made available to the public. A reasonaole
opportunity for submission of oral and written comments must be provided.
The opportunity for a public meeting near the site is required regarding
the proposed plan. Any findings concerning compliance with federal and
state cleanup standards must be provided to the public.
A public comment period for the Stout Operable Unit Feasibility Study (OUFS)
and Proposed Plan was held from August 20 through September 21, 1987. A
public meeting was conducted on September 1U, 1987, to discuss these documents
and tne Agency's tentatively-selected-alternative.
All released documents were made available for public inspection and
copying at EPA Public Information Centers located on Lewis Road, immediately
east of Times Beach, and at the intersection of Kiefer Creek Road and
Kies Road in Castlewood (Ballwin), Missouri. An onsite EPA public information
center wi11 be established and remain open during implementation of
remedial action at the Stout area. This information center will remain
open until onsite activities are completed. Tnese EPA information facilities
provide the opportunity for public access to information 6 days a week.
Tne opportunity for public participation has been provided prior to and
during all dioxin cleanup activities in Missouri since £.°A began actively
investigating potential Missouri aioxin sites in 1982. Cleanup activities at
several Missouri dioxin sites to date have consisted of removal actions
taken to reduce exposure to dioxin-contaminated soils by containment and by
excavation and secure storage. Public meetings have been conducted prior
to all removal activities implemented since 1984 to solicit public comments
so that the Agency could be aware of and responsive to the public's concerns.
Cleanup measures being addressed in this document represent interim
actions for tne management of dioxin-contaminated soils prior to final
management. Final management of dioxin-contaminated materials is being
addressed separately, and was evaluated in the Feasibility Study of Final
Remedial Actions for the Minker/Stout/Romaine Creek Site.
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A public comment period was held for the Feasibility Study of Final Remedial
Actions for the Minker/Stout/Romaine Creek Site from August 8, 1986, until
September 5, iy86. A public hearing was held on August 2b, 1986, at a local
public facility.1n order to discuss the alternatives evaluated in the study
and tne Agency's proposed remedy. At the puolic meeting it was announced tnat
the only alternative in the study which the Agency currently considered feasible
for final management of contaminated soils was offsite thermal treatment within
bU miles of the site. It was also announced that the State of Missouri had
recommended and suggested the evaluation of Times Beach as a possible location
for siting a mobile thermal destruction unit. It was announced that a
feasibility study to evaluate Times Beach as a potential location for offsite
thermal treatment would be completed and released for public comment in
January 1987.
ALTERNATIVES EVALUATION
SITE OBJECTIVES
beneral site-specific objectives are 1} to prevent or reduce long-term human
contact with soils containing dioxin at concentrations exceeding the action
level which is determined to be protective of public health and the environment,
2) to minimize the potential for offsite migration of dioxin. Operable unit
alternatives must be consistent with the final remedial action. An objective
of all alternatives involving treatment is to achieve destruction and removal
efficiencies (LJRE's) which meet applicable or relevant and appropriate regulatory
criteria.
The Stout Operable Unit Feasibility Study evaluated removal of soil and sediment
exceeding an action level of 1 ppb. Federal and state health officials have
determined that 1 ppb in a residential area is a reasonable level at which to
express concern about public health risks. Complete removal of the entire
fill supporting the mobile home pads was also evaluated.
DESCRIPTION OF ALTERNATIVES
A brief description of the operable unit alternatives is given in this section.
Five alternatives have been given consideration for the interim remedy proposed
for the Stout area. Additional development, description, and evaluation of
each alternative is presented in the Stout OUFS.
Alternative 1: No Action
Under the no-action alternative, no additional remedial actions would be taken
at the Stout area.
Alternative 2: Limited Action
Limited action would involve implementation of site use restrictions, as deemed
necessary, seeding sparsely vegetated or unvegetated areas, and providing
surface water controls and annual monitoring.
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Alternative 3: Stabilization
This alternative would include the same scope items as described for
Alternative 'i plus the additional measures of quarterly monitoring and
in-place stabilization of the sediments contaminated at levels greater
than 1 ppb. Stabilization would be accomplished by installing a porous mat
over the ground surface and promoting the growth of vegetation into and
through the mat by seeding and fertilization.
Alternative 4: Excavation to 1 ppb and Storage
Alternative 4 would involve excavation and temporary onsite storage of
soils contaminated at concentrations exceeding 1 ppb to a maximum depth
of 4 feet or bedrock. It is estimated that 3,bUU to 5,700 cubic yards
would be excavated and stored if this alternative were implemented. It
is assumed that the excavated soils would be stored in semi bulk sacks
placed in metal buildings, as has been done by the EPA during removal
actions performed at other Missouri dioxin sites. The OUFS assumed that
excavated soil would be placed in interim storage inside fully enclosed
steel storage structures located on the former Baczynski property, which'
is now state-owned.
Alternative 5: Complete Excavation and Storage
Alternative 5 would involve excavation and temporary onsite storage of
the entire Stout fill area. It is estimated that the volume of soil
which would require storage if this alternative were Implemented would
range from 4,QUO to 8,7bO cubic yards. Storage would be as described for
Alternative 4. Sufficient space may not exist at the former Baczynski
property for interim storage of all excavated material. The former
Edwards property, now state-owned, was identified in tne OUFS as a possible
contingency storage location. The former Edwards property is a portion of
the M1nker/Stout/Romaine Creek site located adjacent to Romaine Creek near
the Minker area.
EVALUATION OF ALTERNATIVES
The five operable unit alternatives considered in the detailed evaluation
were compared to CERCLA criteria for the selection of remedy. These remedy
selection criteria include the following:
0 Compliance with ARARs
0 Reduction of mobility, toxicity, or volume of
waste
0 Short-term effectiveness
0 Long-term effectiveness
0 Permanence
0 Implementability
0 Cost
0 Community and state acceptance
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Table I presents an evaluation of each alternative against these evaluation
criteria. A discussion of each criteria and their attainment by each of
the alternatives follows:
Compliance with ARARs
Section 121(a) of CERCLA, as amended by SARA, requires that remedial
actions comply with requirements or standards under federal and state
laws for the protection of public health and the environment. Section 121(d)
allows a remedy to be selected that-does not attain a level of control at
least equivalent to a legally applicable or relevant and appropriate
requirement (ARAR) if the remedy selected is only part of a total remedial
action that will attain such a level of control when completed. The
operable unit alternatives evaluated in the feasibility study represent
only part of the complete remedy for the Stout area. It is not necessary
for these alternatives to comply with all ARARs. The alternatives will,
however, be compared to ARARs and evaluated to determine the extent to
which each is consistent with a final remedy which attains ARARs.
All alternatives evaluated are consistent with final remedial actions
which involve treatment or disposal. A complete remedy involving the
treatment or disposal of dioxin-contaminated soils could potentially meet
all ARARs. The operable units evaluated are therefore consistent with
complete remedies which meet ARARs.
Tne land ban regulations governing the land disposal of dioxin-contaminated
wastes are expected to go into effect in November 1988. Final disposal
of soils from the Stout area is not expected to occur before this date.
The land ban regulations state that dioxin-contaminated soils can be land
disposed if they pass the Toxicity Characteristics Leaching Procedure
(TCLP)a Based upon existing sample results from the Stout area, it is
expected that the excavated sediments would pass the TCLP test and be
exempt from the dioxin land ban.
Permits are not required for onsite remedial actions at Superfund sites.
Although formal permits are not required, any action must meet the substantive
technical requirements of the permit process. Storage structures included
in alternatives involving excavation and interim onsite storage of contaminated
soils will be designed and constructed in compliance with the substantive
requirements of the Resource Conservation and Recovery Act, as amended
(RCRA).
Reduction of Mobility, Toxicity, or Volume of Waste
Section 121(b) of CERCLA, as amended, states that remedial actions involving
treatment which permanently and significantly reduces the volume, mobility,
or toxicity of hazardous materials are to be preferred over those not
involving such treatment. This evaluation criteria relates to the ability
of a remedial alternative to control or eliminate risks caused by the
mobility, toxicity, or volume of a hazardous waste.
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TABLE 1. REMEDY SELECTION CRITERIA • STOUT
ALTERNATIVE
COMPLIANCE WITH
ARABS
REDUCTION OF
MOBILITY, TOXICITY.
OR VOLUME OF WASTE
SHORT-TERM
EFFECTIVENESS
LONG-TERM
EFFECTIVENESS
|Consistent uith
|complete remedy which
[complies with ARARS.
1: No Action
(No reduction of (Risks to public health
(mobility, toxicity, or (and the environment
(volume. Some increase (remain at current
|in contaminated soil (levels.
(volume requiring future |
(excavation may occur due)
(to contaminant migra- |
|tfon. |
(Consistent with
(complete remedy which
(complies with ARARS.
2: Limited Action
(Consistent with
(complete remedy which
(complies with ARARS.
,3: Stabilization
I I
(No reduction of (Low potential for
(mobility, toxicity, or (exposure to community
(volume. Some increase (or environment in excess
Jin contaminated soil (of current levels or
(volume requiring future (exposure to workers
(excavation may occur due(during implementation.
(to contaminant migra- (Implementation could
(tion. (be performed fn
| (approximately 1 month.
I I
(No reduction in toxic- (Greater potential for '
(ity. Volume of material (exposure to workers and
(requiring eventual exca-|community relative to
(vation will increase duefalt. 2 due to soil dist-
|to volume of stabilizat-Jurbance. Temporary
(ion material. Mobility (disturbance of wildlife.
(would be reduced and (implementation could
(could be controlled with(be performed in
(adequate maintenance. (approximately 2 months.
(Existing contaminants
(would remain in place
(unless migration occurs.
(Risks to public health
(and the environment
(remain at current
(levels. Site boundaries
(may expand due to
(continued migration.
I
(Monitoring program would
(detect eontaminant aigra-
|tion. Fencing would control
(access to existing contao-
finated soils. Low OIM req-
(uirenents. Protection
(achieved (mediately upon
(completion.
(Reduced potential for
(exposure to community and
(environment. Existing cont-
(aminants remain in place.
(Moderate OSM requirements to
(maintain vegetation. Reliab-
(ility of vegetative cover
(uncertain. Vegetation may be
(difficult to maintain.
{ • (Consistent with
{ (complete remedy which
1 (complies with ARARS.
I
4: Partial Excavation (Storage structures
(No reduction in toxic- (Increased potential for
|ity. Mobility control led(exposure to workers and
(by containerization and (cooinunity due to soil
(secure storage. Volume (disturbance. Temporary
(of contaminated soil (disturbance of wildlife.
(designed and constructed)fixed at current level. (Implementation could
(to RCM standards. (Estimated 3,500-5,700 cy|be performed in approx-
| (of material would re- (imately 4-6 months.
| (quire final management. |
(Exposure potential reduced
(to residential standards.
(Soil TCDD levels permanently
(reduced to less than 1 ppb.
(Potential bioaccuutation
(adequately reduced. Protec-
(tion achieved {mediately
(upon completion. Limited OSM
(requirements for structures.
I-
(Ho reduction in toxic- (Increased potential for
|ity. Mobility control led(exposure to workers and
(by containerization and (community due to soil
(secure storage. Volume (disturbance. Temporary
(of contaminated soil (disturbance of wildlife.
(designed and constructed)fixed at current level, (implementation could
|to RCRA standards. (Estimated 4,000-8,750 cyfbe performed in approx-
| (of material would re- (imately 4-6 months.
j (quire final management. |
(Consistent with
(complete remedy which
(complies with ARARS
I
Complete Excavation (Storage structures
I"
(Exposure potential for conra-
|unity and environment tlin-
(inated. No residual contam-
(ination would remain.
(Potential bioaccuaulation
(eliminated. Protection
(immediate upon completion.
(Limited OIM requirements
(for storage structures.
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' ;;••" • sr»T (cont.,
I -
' '"° <">«« ,-np.c, - COST
/' I'l'^r-' "• i
('•".Ac,,., '«"—" .iri., ' '
' requiring ff-., I '
,' /r-'•---''',' I
/ /decrease due fn ' '
J l«*« -SiZ."*- * ^ Oncost:
/ / I I
' /* -"•« inpac't" ': '
°" '«ure management Straf9ht^ward f^. ,
/ /"-equiren^*. ^* /•ntation. u ?tem I I - --,
, - "fction , ~ •" '""tertal i ---*r uue f« ._, . •-- — •»•» worrh. i v "y fnf»c«.-~ .
. ^'""i «n.t n.^. ^« site fne^.
I /ment imv *» lers. Acces* «- .,. I
' *—• ZT^L I"'"" *•<"« '
< • /'—.,„."'-/—^,«. , -_. ,.cttaw
1 ' ' I «.„ /""•«•««.
-; /-
/Total
I
I
. —-swnenc at ;„ - ">-*-ess to i »n,000 Itn B "**« f
/current (~., . /Private oro«..... ' 'to a^ess property and
"*« twice. j
I '"'"t" PHt't^l .„. '
°^ "«•• L so>'" «"'».
"« «nsfstent
f luifli - I
/
/ I
:^*.i0"'T°<'< Present _ ^^w"^!'--/
I
' '^^re^,^ ^«MCOSI: CS^«-
I Distent with p.9t
t ... ^.ooo "'"•"'-•
K?-^- b^--- - !- ,'
^^:ra- r^"^ f-—: /^^^r-;
/would f.*fif... Meets* to !»*._.. ' /removal of e«,.._..._.
Ovation £,T'rfZatf°°
/^^/^ i«x^zr?.rr./«.-«.«, -,«... /-'«•.i^r;^ /
i
/r^..,. . w w /
• 12,000
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Alternative 1, No Action, would nave no direct impact on the mobility,
toxicity, or volume of hazardous materials in the Stout area. However,
failure to stabilize or contain dioxin-contaminated soils may expand site
boundaries due to contaminant migration, resulting in an increased soil
volume requiring final management. Toxicity of the existing contamination
would remain at current levels for all alternatives, prior to final
management.
Implementation of the limited-action alternative would reduce the mobility
of the. contamination somewhat by enhancing existing vegetation. The
volume of hazardous materials requiring management could potentially increase
due to migration.
Stabilization of contaminated areas would reduce the potential for erosion
and transport to a greater extent than limited action. Implementation of
this alternative would result in an increase in the soil volume requiring
final management due to the volume of stabilization material.
Alternatives involving the excavation and interim onsite storage of
contaminated soils would result in a substantially decreased potential for
migration. Mobility of excavated material would be eliminated due to
containerization and secure storage. Migration of soils containing TCDD
below the action level of 1 ppb could continue to occur, but would not be
expected to result in TCDD exposure above a level of concern for public
health and the environment. It 1s anticipated that no additional excavation
would be necessary to maintain surface soil concentrations below 1 ppb.
Complete excavation of the entire fill area would remove all potentially
contaminated soil from the Stout area, eliminating any potential for
additional migration of existing contamination. Excavation alternatives
would fix the soil volume requiring final management at current levels.
Snort-Term Effectiveness
Short-term effectiveness measures how well an alternative provides protection
of the environment, community, and workers during construction, and the
time required for Implementation.
Short-term risk to public health and the environment would remain at current
levels for Alternative 1. However, there would be no increase in risk to workers
or the public due to construction activity or disturbance of contaminated soil.
During implementation of Alternative 2, there would.be low potential for exposure
to workers, but no increased exposure potential to the community or environment
Stabilization of the creek bed would result in greater potential for
worker exposure due to increased opportunity for contact with contaminated
soils during implementation. Soil disturbance would increase the potential
for exposure to the community through erosion by water and wind, and
could temporarily disturb wildlife.
Excavation and interim storage of contaminated soil would also involve
soil disturbance and related exposure opportunities. This exposure
potential could be controlled by application of dust suppressants and monitoring.
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Severe storms may spread contamination during implementation of stabilization
or excavation activities. The spread of contamination due to precipitation
coulci be controlled by placement of a daily cover over exposed areas.
Complete excavation of the entire area would involve a somewhat larger
area with greater opportunity for wildlife disturbance and community and
worker exposure.
Long-Term Effectiveness
Long-term effectiveness addresses the long-term protection and reliability
that An alternative affords. This includes the risk to the community
once the remedy is in place, risk to workers during operation and maintenance
(O&M), environmental risk due to residual hazardous substances, long-term
reliability, U&M requirements, time required to achieve protection, and the
difficulty in detecting and mitigating problems with the completed remedy.
Existing contamination would remain in place and unmanaged for the no-action
and limited-action alternatives. Site boundaries could potentially
expand due to contaminant migration through erosion. If this occurred, the
resulting increased volume of contaminated sediment would increase the
scope and cost of future management.
Limited action would provide a monitoring program to detect the spread of
contamination, and fencing to control access to contaminated areas.
Fencing and posting may not prevent all site intruders from access.
Limited action would have low O&M requirements, could be easily inspected,
and repairs would be straightforward. Limited action would achieve its
full degree of protection immediately upon implementation of the remedy,
as would all of the alternatives evaluated.
Stabilization of the fill area could-reduce exposure potential to the
community and environment by controlling dispersion of contaminated soil
due to erosion by wind and water. Existing levels of contamination would
remain in place. The potential for bioaccumulation would continue to
exist at a reduced rate. Operation and maintenance requirements
may be significant in order to maintain year-round vegetation in all
contaminated portions of the fill area. Quarterly O&M may not be sufficient
to maintain vegetation in some areas. Workers performing routine O&M
could potentially be exposed to elevated TCDD levels. Ineffectiveness of
the stabilization could result in the migration of contaminants which could
expand site boundaries and increase the soil volume requiring final management.
Excavation of contaminated sediment exceeding 1 ppb would reduce community
exposure potential to residential standards. Potential oioaccumulation
of TCDD in biota would be possible if levels below 1 ppb remain in place,
but would be expected to be substantially reduced from current levels.
Potential bioaccumulation of dioxin in biota does not represents significant
risk to human health, however, since contaminated biota are not expected
to enter the human food chain, due to the fact that surveys have shown that
no recreational or commercial harvesting of indigenous species takes
place in this area.
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Limited 0#M requirements would be associated with maintaining the storage
structures for both excavation alternatives. There would be no U4M
requirements for the excavated till area. Problems with the remedy could
easily be detected during inspection of the storage structures and repaired.
The risk of system failure is very low.
Kxcavation and interim onsite storage of the entire fill area would
provide the maximum degree of long-term protection to public health and
the environment of the alternatives evaluated. No residual contamination
would remain in the fill. Exposure potential for the community and
environment and the potential for bioaccumul.ition in the creek would be
eliminated. Limited U*M requirements would be associated with the storage
structures. Problems with the remedy could be easily detected during
inspection and repaired.
Permanence
The criteria of permanence is similar to long-term effectiveness, but
with an emphasis on the need for management of treated residuals and
untreated wastes. Tne operable unit alternatives evaluated represent
interim measures which can be implemented prior to final management of
the contaminated soils. Permanence of each operable unit alternative
concerns the extent to which future management of contaminated soils will
be necessary.
Implementation of the no-action and limited-action alternatives will have
no direct impact on future management requirements, although the volume
of soil requiring final management could either decrease or increase due to
migration of contamination.
Stabilization would be effective at controlling migration of contaminated
soil, thereby fixing the volume of soil contaminated ^n excess of 1 ppb
at the current level. There would be some increase in future management
requirements due to the n«ed to manage the stabilization materials.
Partial excavation of sediment would result in the permanent reduction of
*n-place contaminated levels to below 1 ppb. The volume of soil requiring
future management would be fixed at the current level. Future handling
of soils would be facilitated due to contdinerization of wastes. Partial
excavation of the fill could potentially remove all contamination if
contaminated soil is limited to the surface. Complete excavation of
contaminated soils would permanently remove all existing contamination
from the fill area, fixing the volume of material to be managed in the future
and facilitate future handling.
Implementability
This criteria measures the technical difficulties, reliability, and
availability of each alternative. Implementability also involves the
administrative feasibility of each alternative. No permits would be
required for any of the actions evaluated since CEKCLA onsite actions are
exempt from penni tting requirementsv by law.
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The implementability criteria does not apply to the no-action alternative,
since no measures would be taken to mitigate the contamination. Implementation
of limited action would be straightforward. The reliability of the
limited-action alternative is not certain. Site intruders could ignore
warning signs and scale fences. Contamination may migrate downgradient
resulting in additional areas requiring access restrictions. Implementation
of stabilization technologies would be straightforward. The reliability
of stabilization may be impacted by severe storms which could disrupt the
stabilized areas.
Implementation of the partial excavation alternative could be facilitated
by appropriate construction techniques. A comoination of conventional
excavation equipment and vacuum equipment could be used to efficiently
remove lifts of soil from the fill without recontaminating the area. The
reliability of partial excavation would be very high upon completion.
The storage structures would last indefinitely if properly maintained.
Implementation of the complete excavation alternative would be straightforward,
although it may be difficult to determine the point at which native soil is
encountered, which could result 1n overexcavation and substantial sampling
requirements. Removal actions involving excavation and Interim onsite
storage of TCOD-contaminated soils have been successfully implemented at
several nearby sites 1n eastern Missouri.
Cost
The total present worth cost of each alternative 1s presented in Table I.
Costs listed for Alternatives 4 and 5 involving excavation and interim
storage include the cost of removal and decontamination of the storage
structures upon implementation of final management. Also included 1n
Table I 1s the estimated annual Operation and Maintenance (0£M) cost associated
with each alternative.
Community and State Acceptance
During past public meetings conducted for other portions of the M1nker/Stout/
Romaine Creek site and other nearby dloxin sites, the community was given
the opportunity to express their preference for management of contaminated .
soils. Affected residents are in general agreement that the contaminated
soil should be excavated and transported offsite for treatment or disposal.
At the present time, there is no offsite treatment or disposal facility
capable of receiving the dioxin-contaminated soils. Interim storage
is therefore necessary until an offsite management .option develops. The
community is likely to be supportive of excavation of contaminated soil
and removal of the associated risk to public health. Given the absence of
an offsite management option, the public will probably accept interim
storage as the only alternative available at this time. Interim storage1 is
consistent with the community supported final management option of offsite
treatment or disposal. Some local objection can be expected near the
location where the required storage structures are sited.
Several removal actions have been completed in the recent past involving
excavation and interim storage of contaminated soils at nearby eastern -
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Missouri dloxln sites. The State of Missouri has in the past been supportive
of these actions if they achieve adequate protection of public health and
the environment. The state has indicated its support for excavation and
interim storage of soils exceeding 1 ppb at the Stout area.
SELECTED REMEDY
INSCRIPTION OF THE SELECTED REMEDY
The interim remedy which the Ayency has selected to implement as an operable
unit remedial action involves excavation of soils exceeding 1 ppb TCDD to'
a maximum depth of 4 feet or bedrock'. Excavated areas would be backfilled
to original grade with clean material and reveyetated. This remedy is
developed and described in detail as Alternative 4 in the Stout Operable
Unit Feasibility Study.
Excavation of contaminated soil exceeding 1 ppb at the Stout area will be
performed using conventional earthmoving and vacuum equipment, or other
appropriate means of efficiently removing lifts of soil, thereby minimizing
the potential for recontamination. An effort will be made to minimize
the amount of material removed from the Stout area, while maintaining the
assurance that soils exceeding 1 ppb are not left in place. Minimizing
the volume of soil removed from the Stout area .reduces the required
Interim storage space and associated final management costs for the
removed material. Any identified technology or procedure capable of
reducing the amount of material removed from the Stout area will be
Investigated during the design phase.
All TCOD concentrations will be determined at the" 95 percent confidence
level using the procedure developed in 1984 for cleanup of other eastern
Missouri dioxin sites. This procedure has undergone peer review and
approval by federal and state health agencies including the Centers for
Disease Control/ Center for Environmental Health, Environmental Protection
Agency, Missouri Division of Health, and the Missouri Department of
Natural Resources. This procedure determines the maximum expected surface
contaminant level in unit areas of approximately 5,1)00 square feet at the
95 percent confidence level.
Excavated soil will be containerized in woven polypropylene, polyethylene-lined
bulk handling sacks similar to those currently and .previously in use at
eastern Missouri dioxin removal locations, including Qua^l Run, Castlewood,
and the Mlnker, Cashel, and Sullins portions of the Minxer/Stout/Romaine Creek
site. These bulk-handling sacks will be loaded by hopper and transported to
fully-enclosed temporary storage structures constructed onsite. Storage
structure design will be similar to those in use at other eastern Missouri
dioxin sites. One 50-foot by 100-foot building has a capacity of approximately
1,100 cubic yards of containerized soil. It is estimated that four such
structures will be required onsite to store the volume of contaminated
material anticipated to be excavated from the Stout area.
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Excavated materials will be placed in Interim storage until a final
management option can be selected. It will be initially attempted to store
all material excavated from the Stout area in storaye structures located
on the former Edwards property, adjacent to Romaine Creek. If sufficient
space does not exist on this property for storage of all removed material
from Romaine Creek and the Stout area, the former Baczynski property on
Swaller Road will be considered for a contingency storage location. The
former Baczynski property will only be considered for storage in the event
that available storage space at the former Edwards property is exhausted.
If a final management alternative becomes available and is selected in a
separate Record of Decision for material removed from the Stout area, it
is possible that interim storage of the excavated material will not be
necessary, and that contaminated soil can,be taken directly to the location
where final management is available. This decision would be documented
in a subsequent Record of Decision for final management of dloxin-contaminated
materials from the Minker/Stout/Romaine Creek site.
RATIONALE FOR PREFERENCE
The selected interim remedy is preferred over the no-action and limited-action
alternatives primarily because leaving contaminated soil in place does
not provide adequate protection of human health or the environment.
The contaminated soil in the fill area is not currently being managed 1n
a manner which is protective of human health and the environment. Contaminant
migration could expand site boundaries to areas where access is not
restricted by fencing. Exposure to nearby residents or visitors via
direct; contact and ingestion could occur in excess of a level of concern
for protection of human health in residential areas reco.mmended by federal
and state health agencies. Stabilization of contaminated soils is not
being proposed due to the uncertainty of successful implementation and high
04M requirements. Stabilization would also involve the future disruption of
contanninated soils and disturbance of nearby residents an additional time
for final management.
STATUTORY DETERMINATIONS
Removal and temporary onsite storage of soils exceeding 1 ppb 1n the
Stout area is being selected because this alternative attains the objectives
of the interim remedy and satisfies th.e remedy selection criteria. The
selected operable unit remedial alternative is protective of human health
and the environment, is compatable with potential final remedial actions,
and is cost-effective. Protection of human health and tne environment is
provided by reducing the potential for human and environmental contact
with contaminated soil and reducing the potential for continued erosion of
contaminated soils. Contaminated soil is containerized and isolated in a
secure storage facility, thereby eliminating the potential for human or
environmental contact with TCOD concentrations exceeding I ppb. Some
migration of soil left in place at concentrations less than 1 ppb may continue
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to occur, but this migration is not expected to result in the development
of contaminant levels exceeding a level of concern for public health. It
is anticipated that natural degradation and erosion processes will result
in the gradual reduction of contaminant levels to near background levels.
The selected interim remedy also attains the objective of compatibility
with final remedies. The interim remedy is compatible with potential
offsite treatment or disposal options. Future handling of the contaminated
material will be facilitated by containerization. The interim remedy is
not compatible with final remedial action alternatives involving in-place
containment or treatment. In-place alternatives, however, do not compare
favorably to offsite alternatives for final management of contaminated
soil, and are not being proposed by the Agency.
Although a final remedy has not been selected for contaminated soils
from the Minker/Stout/Romaine Creek site, the Agency has proposed
offsite thermal treatment for final management of this material. This
proposed final remedy satisfies the statutory preference under SARA
for remedies which utilize treatment technologies resulting in the
permanent reduction of toxicity, mobility, or volume of hazardous waste.
The selected remedy has been determined to be the most cost-effective
operable unit alternative which provides protectiveness. Only the two
removal alternatives evaluated will assure the continued protection of
public health and the environment. Complete excavation of the entire
fill area cannot be justified at the additional cost because both alternatives
reduce surface TCDO concentrations below 1 ppb which assures protection of
public health and the environment. The potential for-bioaccumulation in
wildlife is expected to decline following removal of soil exceeding 1 ppb.
As residual concentrations are further reduced through natural processes,
a corresponding decline in-potential bioaccumulation is expected.
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