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	
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  J                l«*« -SiZ."*- *              ^ Oncost:
  /                /	       I              I
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                  °" '«ure management   Straf9ht^ward f^.   	,
 /               /"-equiren^*.  ^*  /•ntation. u	?tem  I             I   -	--,
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 I                /ment imv *»	     lers. Acces* «-  .,.    I
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                                           /Total
                                           I
                                           I

               .    —-swnenc at   ;„ -    ">-*-ess to    i        »n,000 Itn    	 B "**«   f
               /current (~.,  .     /Private oro«.....     '             'to a^ess property and
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                                       /
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                                                                     I
             '              '^^re^,^    ^«MCOSI:    CS^«-
             I                                         Distent with p.9t
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            ^^:ra-  r^"^  f-—:  /^^^r-;
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         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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                                   1U


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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                                     11
 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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                                    12
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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                                    13
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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                                    14
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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                                    15


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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