EPA/ROD/R08-93/075
1993
EPA Superfund
Record of Decision:
MONTANA POLE AND TREATING
EPA ID: MTD006230635
OU01
BUTTE, MT
09/21/1993
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RECORD OF DECISION
MONTANA POLE AND TREATING PLANT
NATIONAL PRIORITIES LIST SITE
BUTTE, MONTANA
Montana Department of Health & Environmental Sciences
Solid & Hazardous Waste Bureau
Cogswell Building
Helena, Montana 59620
(Lead Agency)
(Support Agency)
United States
Environmental Protection Agency
Region VIII - Montana Office
Federal Building, 301 S. Park, Drawer 10096
Helena, MT 59626-0096
September 1993
RECORD OF DECISION
MONTANA POIiE AND TREATING PLANT NATIONAL PRIORITIES LIST SITE
INTRODUCTION
The Montana Department of Health & Environmental Sciences and the Environmental
Protection Agency (EPA) present the Record of Decision for the Montana Pole and Treating
Plant site (the Site). The Record of Decision is based on the Administrative Record,
Remedial Investigation/Feasibility Study, the Proposed Plan, the public comments
received, including those from the potentially responsible parties, EPA comments, and
other new information. The Record of Decision presents a brief outline of the Remedial
Investigation/Feasibility Study, actual and potential risks to human health and the
environment, and the selected remedy. The state followed EPA guidance[1] l
Guidance on Preparing Superfund Decision Documents: The Proposed Plan, the Record of
Decision, Explanation of Differences, the Record of Decision Amendment, Interim Final,
EPA/540/G, July 1989. in preparation of the Record of Decision. The Record
of Decision has the following three purposes:
1. Certify that the remedy selection process was carried out in accordance with the
reguirements of the Comprehensive Environmental, Response, Compensation and
Liability Act (CERCLA) , 42 U.S.C. 9601 et seg., as amended by the Superfund
Amendments and Reauthorization Act (SARA), and, to the extent practicable, the
National Contingency Plan (NCP);
2. Outline the engineering components and remediation goals of the selected remedy;
and
3. Provide the public with a consolidated source of information about the history,
characteristics, and risks posed by the conditions at the Site, as well as a
summary of the cleanup alternatives considered, their evaluation, and the
rationale behind the selected remedy.
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The Record of Decision is organized into three distinct sections:
• The Declaration functions as an abstract for the key information contained in the
Record of Decision and is the section of the Record of Decision signed by the
Director of the Montana Department of Health and Environmental Sciences and the
EPA Regional Administrator;
• The Decision Summary provides an overview of the site characteristics, the
alternatives evaluated, and the analysis of those options. The Decision Summary
also identifies the selected remedy and explains how the remedy fulfills
statutory requirements; and
• The Responsiveness Summary addresses public comments received on the Proposed
Plan, the Remedial Investigation/Feasibility Study and other information in the
administrative record.
TABIiE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
ACRONYMS
I. SITE NAME, LOCATION AND DESCRIPTION
II. SITE HISTORY
Enforcement Actions
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
IV. SCOPE AND ROLE OF RESPONSE ACTION
V. SUMMARY OF SITE CHARACTERISTICS
Principle Contaminants of concern
Summary of Nature and Extent of Contamination
Major Sources of Contamination from Historical MPTP Operations
Conceptual Model of Contaminant Fate and Transport
Estimated Volumes of Contaminated Materials
VI. SUMMARY OF SITE RISKS
Human Health Risks
Contaminants of Concern for Human Health
Exposure Assessment
Toxicity Assessment
Risk Characterization
Ecological Risks
Contaminants of Concern
Potential Receptors
Ecological Toxicity Assessment
Ecological Risk Characterization
VII. DESCRIPTION OF ALTERNATIVES
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Evaluation and Comparison Criteria
Overall protection of public health and the environment
Compliance with applicable or relevant and appropriate requirements (ARARs)
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Long-term effectiveness and permanence Reduction of toxicity, mobility and volume
Short-term effectiveness Implementability Cost State agency
acceptance Community acceptance
IX. SELECTED REMEDY
Components of Selected Remedy
Estimated Costs of the Remedy
Cleanup Levels
Points of Compliance
Performance Standards for Soils
Performance Standards for Groundwater
Compliance Sampling Program
Engineering and Institutional Controls
Contingency Measures
X. STATUTORY DETERMINATIONS
Protection of Human Health and the Environment
Compliance with Applicable or Relevant and Appropriate Reguirements
Cost-Effectiveness
Utilization of Permanent Solutions and Alternative Treatment Technologies (or
Resource Recovery Technologies) to the Maximum Extent Practicable Preference for
Treatment as a Principal Element
XI. DOCUMENTATION OF SIGNIFICANT CHANGES
XII. REFERENCES
APPENDIX A - Applicable or Relevant and Appropriate Reguirements
APPENDIX B - Administrative Record Index
LIST OF TABLES
Table 1 Contaminated Soil Volume Estimates
Table 2 Preliminary Remedial Action Goals for Soils
Table 3 Contaminants of Concern for Human Health
Table 4 Potential Exposure Pathways Under Current Land Use Conditions
Table 5 Potential Exposure Pathways Under Future Land Use Conditions
Table 6 Exposure Assumptions for Dermal Contact with Soil for Workers and
Trespassers
Table 7 Exposure Assumptions for Incidental Ingestion of Soil for Workers and
Trespassers
Table 8 Exposure Assumptions for Incidental Ingestion of Surface Water
Table 9 Exposure Assumptions for Direct Contact with Sediments
Table 10 Exposure Assumptions for Dermal Contact with Soil for Residents
Table 11 Exposure Assumptions for Incidental Ingestion of Soil for Residents
Table 12 Exposure Assumptions for Ingestion of Home Grown Vegetables (Compounds
other than Pentachlorophenol)
Table 13 Exposure Assumptions for Ingestion of Home Grown Vegetables Grown in Soil
Containing Pentachlorophenol
Table 14 Exposure Assumptions for Ingestion of Groundwater
Table 15 Exposure Point Concentrations for Surficial Soils
Table 16 Exposure Point Concentrations for Groundwater
Table 17 Exposure Point Concentrations for Surface Water and Sediments
Table 18 Summary of Estimated Risks for Future On-Site Residents
Table 19 Summary of Estimated Risks for Future On-site Workers
Table 20 Summary of Estimated Risks for Current On-Site Trespassers
Table 21 Estimated Cost for Remedial Alternative 5B
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Table 22 Estimated Cost for Soil Flushing System
Table 23 Soil Cleanup Levels
Table 24 Pathway Risk Estimates Corresponding to Soil Cleanup Levels Table 25
Groundwater Cleanup Levels
Table 26 Surface Water Cleanup Levels
Table 27 Discharge to Surface Water Cleanup Levels
Table 28 Toxicity Eguivalence Factors for PAHs
Table 29 Toxicity Eguivalence Factors Dioxins and Furans
LIST OF FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure
Figure
15
16
Figure 17
ACRONYMS
Butte, Montana Area Map
MPTP Site Layout and Features
PCP and TPH Concentrations in Surface Soils
PCP Concentrations in Subsurface Soils
Subsurface Soil Boring Cross Sections
PCP Concentrations in Subsurface Soil Boring Cross Section A-A'
PCP Concentrations in Subsurface Soil Boring Cross Section B-B'
PCP Concentrations in Subsurface Soil Boring Cross Section C-C'
Surface Water, Groundwater and LNAPL Contamination
PCP Concentrations in Groundwater (site area)
PCP Concentrations in Groundwater (downstream area)
Estimated Lateral Extent of PCP Plume (site area)
Estimated Extent of LNAPL Plume
PCP, PAH and TPH Concentrations in Surface Water
PCP, PAH and TPH Concentrations in Creek Sediments
Site Conceptual Model
Estimated Lateral Extent of Surface and Subsurface Soil Contamination
ARAR Applicable or Relevant and Appropriate Reguirements
ARCO Atlantic Richfield Company
AWQC Ambient Water Quality Criteria
BRA Baseline Risk Assessment
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980
DNAPL Dense Non-Agueous Phase Liguid
EPA U.S. Environmental Protection Agency
ERA Ecological Risk Assessment
FS Feasibility Study
GAG Granulated Activated Carbon
HI Hazard Index
LAO Lower Area One
LNAPL Light Non-Agueous Phase Liguid
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
MDHES Montana Department of Health and Environmental Sciences
MPTP Montana Pole and Treating Plant
NCP National Contingency Plan
OSWER Office of Solid Waste and Emergency Response
PA/SI Preliminary Assessment/Site Inspection
PAH Polynuclear Aromatic Hydrocarbon
PCDD Polychlorinated dibenzo-p-dioxins
PCDF Polychlorinated dibenzofurans
PCP Pentachlorophenol
PRAG Preliminary Remedial Action Goal
PRP Potentially Responsible Party
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RA Remedial Action
RCRA Resource Conservation and Recovery Act
RD Remedial Design
RfD Reference Dose
RI Remedial Investigation
ROD Record of Decision
SARA Superfund Amendments and Reauthorization Act
TCDD Tetrachlorodibenzo(p)dioxin
TEF Toxicity Eguivalence Factor
TPH Total Petroleum Hydrocarbons
UV Ultraviolet (light)
VOC Volatile Organic Carbon
DECLARATION
MONTANA POLE ROD - DECLARATION
SITE NAME AND LOCATION
Montana Pole and Treating Plant Site
Butte, Montana
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedy for the Montana Pole and Treating
Plant site (the Site), in Butte, Montana. The Montana Department of Health &
Environmental Sciences (MDHES), in consultation with the United States Environmental
Protection Agency (EPA) , selected the remedy in accordance with CERCLA, as amended by
SARA, and, to the extent practicable, the NCP. The EPA concurs and adopts the selected
remedy. The attached index identifies classes of documents or records that comprise the
administrative record upon which the selection of the remedial action is based.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed
by implementing the response action selected in this Record of Decision, may present an
imminent and substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE SEIiECTED REMEDY
This is the final action for the only operable unit for the Site. The operable unit
includes all known sources and contaminated media at the Site. This action addresses the
principal threats remaining and provides for treatment of contaminated soils and
groundwater. Some treatment residuals and soils contaminated at lower levels will
remain on-site, such that the Site will reguire long-term management.
The principle contaminants of concern at the Site are pentachlorophenol (PCP) ,
polynuclear aromatic hydrocarbons (PAHs), polychlorinated dibenzop-dioxins and
polychlorinated dibenzofurans. This Record of Decision establishes cleanup levels for
these and all other contaminants of concern at the Site. The major components of the
selected remedy include:
1. Excavation of contaminated soils from accessible areas of the site, to the extent
practicable. The volume of soils is estimated to be approximately 208,000 cubic
yards;
2. Treatment of excavated soils (208,000 cubic yards approximately) and previously
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removed soils (10,000 cubic yards approximately) by above ground biological
treatment;
3. In-place biological treatment of contaminated soils below the depth of excavation
before backfilling;
4. Backfill of excavated and treated soils into excavated areas if possible, surface
grading and revegetation:
5. Soil flushing of inaccessible soils areas (principally underlying Interstate
15/90) in order to recover hazardous substances;
6. Containment of contaminated groundwater and LNAPL using physical and/or hydraulic
barriers (as determined during remedial design) in order to prevent the spread of
contaminated groundwater and LNAPL and to limit releases of contamination into
Silver Bow Creek;
7. Treatment of extracted groundwater using the present EPA water treatment plant
(which consists of oil/water separation followed by granulated activated carbon
treatment). The ultimate design of the groundwater treatment system (as
determined during remedial design) may include the addition of biological means
or ultraviolet oxidation (UV/oxidation) to maximize cost effectiveness of the
treatment system. Treatment will meet standards for discharge or reinjection, as
appropriate;
8. Discharge of extracted, treated groundwater into Silver Bow Creek and/or
reinjection of extracted, treated groundwater into the aguifer (as determined
during remedial design);
9. Enhanced in-situ biological treatment of contaminated groundwater, inaccessible
contaminated soils areas and contaminated soils not recovered by excavation;
10. Treatment of contaminated site debris and eguipment by decontamination followed
by disposal of these materials in a licensed off-site landfill;
11. Treatment of contaminated oils and sludges in a licensed offsite incinerator;
12. Additional institutional controls preventing access to contaminated soils and
groundwater; and
13. Groundwater monitoring to determine movement of contaminants and compliance with
remedial action reguirements.
Both soils and groundwater will be remediated at the Site. Soils will be excavated from
four general areas: surface soil hot spot areas, surface and subsurface soils in the
former plant process area, surface and subsurface soils along the historic drainage
ditch running from the former plant process area to Silver Bow Creek and subsurface
soils near the groundwater table which have been contaminated by floating wood treating
product. The selected treatment technology for contaminated soils is above ground
biological treatment. Some contaminated soils and associated wood treating fluid will
remain in place due to inaccessibility and limits of excavation technology. These
contaminated soils will be treated in place by in situ biological degradation.
Contaminated groundwater and any residual woodtreating fluids left after excavation,
will be contained from further migration using hydraulic and/or physical barriers. To
create hydraulic containment of contaminated groundwater, some contaminated water will
be extracted, treated and discharged to Silver Bow Creek. Other extracted and treated
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water will be reinfiltrated onsite to assist in hydraulic containment, flushing of
contaminated areas and in situ biological degradation. Extracted groundwater will be
treated above ground in the water treatment plant constructed at the site by EPA. This
facility presently consists of oil/water separation and granulated activated carbon
treatment. The ultimate design of the groundwater treatment system may include the
addition of biological means or ultraviolet oxidation (UV/oxidation) to maximize cost
effectiveness of the treatment system.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with
federal and state requirements that are legally applicable or relevant and appropriate
to the remedial action, and is cost-effective. This remedy uses permanent solutions and
alternative treatment (or resource recovery) technologies to the maximum extent
practicable and satisfies the preference for remedies that employ treatment that reduces
toxicity, mobility, or volume as a principal element. Because this remedy may result in
hazardous substances remaining on-site above health based levels, the five year review
will be conducted within five years after commencement of remedial action to ensure that
the remedy continues to provide adequate protection to human health and the environment.
DECISION SUMMARY
MONTANA POIiE ROD - DECISION SUMMARY
I. SITE NAME, LOCATION AND DESCRIPTION
Montana Pole and Treating Plant Butte, Montana
The Montana Pole and Treating Plant site is located at 202 West Greenwood Avenue, on the
western edge of Butte, Montana, in the southeast quarter of Section 24, T3N, R8W (see
Figures 1 and 2). Generally, the site is bordered on the north by Silver Bow Creek, on
the south by Greenwood Avenue, on the west by a former smelter site and on the east by a
railroad right-of-way. U.S. Interstate 15/90 runs across the site in an east-west
direction and partitions the site into a northern and a southern section. Portions of
the Site lie within the 100 year floodplain. The Lower Area One (LAO) Operable Unit of
the Butte/Silver Bow Creek Superfund site overlaps the Site on the north.
The Site is located in a mixed land use area. Much of the land in the vicinity of the
Site has been used industrially, usually associated with past and present mining
activities, though commercial and residential areas are immediately adjacent to the
Site. Two neighborhoods are within a quarter mile of the site. There is one residence,
an auto body shop and an architect's office located on site. Groundwater use in the
area is limited. In the residential area east of the site, there is one well which is
currently being used for domestic purposes. The Mount Moriah cemetery south and
upgradient of the site uses groundwater for lawn watering.
II. SITE HISTORY
The Montana Pole and Treating Plant operated as a wood treating facility from 1946 to
1984. During most of this period, a solution of about five percent pentachlorophenol
(PCP) mixed with petroleum carrier oil similar to diesel was used to preserve poles,
posts and bridge timbers. The PCP solution was applied to wood products in butt vats
and pressure cylinders (retorts). Creosote was used as a wood preservative for a brief
period in 1969.
The plant initially included a pole peeling machine, two butt treating vats, and related
ancillary facilities. In April 1947, the first load of treated timbers was shipped
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off-site. Major modifications to the plant occurred between 1949 and 1951, and again
around 1956. Sometime between 1949 and 1951, a 73-foot-long, 6-foot-diameter retort was
installed to increase timber treatment production efficiency. A second retort, which
was 66 feet long with a 7-foot diameter, was installed around 1956. The retorts were
used both to dry green timber using the Boulton process, and to pressure treat timber
with a petroleum/pentachlorophenol (PCP or penta) mixture. Drying timber by the Boulton
process generated steam which was condensed. The condensate was discharged to two hot
wells where the condensate partially separated into an oil and water phase. The water
phase from the hot wells was reportedly discharged into an on-site unlined drainage
ditch which flowed northward toward Silver Bow Creek. On-site sedimentation ponds were
also apparently used for waste disposal purposes.
The retorts and butt treatment vats were in continuous operation until May 1969. On May
5, 1969, an explosion occurred while a charge of poles was being treated in the east
butt treating vat. The explosion generated a fire which destroyed the east vat, boiler
room, and retort building. Although the boiler, retorts, and auxiliary eguipment were
damaged, the plant was rebuilt and functional by December 1969. The west butt treatment
vat was not destroyed by the fire and was thereafter used for some timber treatment and
mixing the petroleum/PCP product used in the retorts. Petroleum/PCP product reportedly
spilled from the east butt treating vat as a result of the explosion and fire.
Additional seepage of product occurred from both retorts as a result of broken pipes and
valves damaged by the fire. Reportedly, on-site tanks were not ruptured as a result of
the fire.
A small on-site sawmill was constructed in the fall of 1978 and was fully operational by
the fall of 1979. Additionally, in response to implementation of the Resource
Conservation and Recovery Act (RCRA), a closed-loop process water system was constructed
in 1980. The primary function of this system was to eliminate overland discharges of
Boultonizing water (generated from the drying of green timber). The closed-loop water
recovery system operated by collecting wastewater in storage tanks, recirculating this
water through the condensing system, and evaporating excess water using aeration sprays.
On May 17, 1984, the Montana Pole and Treating Plant ceased operations.
Enforcement Actions
In March 1983, a citizen filed a complaint concerning oil seeping into Silver Bow Creek
near the Montana Pole facility. MDHES investigated the complaint and discovered an oil
seep on the south side of Silver Bow Creek directly downgradient from the Montana Pole
facility. Further investigation of the site revealed oil-saturated soils adjacent to
the creek and on Montana Pole property. Subseguent sampling confirmed the presence of
PCP, polycyclic aromatic hydrocarbons (PAHs), and dioxins/furans in site soils and oil
samples. MDHES and EPA completed a preliminary assessment and site inspection (PA/SI)
followed by a Hazard Ranking Score in July 1985. The Montana Pole facility was included
on the National Priority List for Superfund sites on July 22, 1987 (Fed. Reg. Vol. 52,
140 Pg. 17623).
In July 1985, the EPA Emergency Response Branch began conducting a removal action on the
site to minimize impacts to Silver Bow Creek and to stabilize the site. EPA excavated
approximately 10,000 cubic yards of highly contaminated soils, bagged them and placed
them in storage buildings (pole barns) constructed on site. Tanks, retorts, pipes and
other hardware were dismantled and stored on site in a former sawmill building. Two
groundwater interception/oil recovery systems were installed to alleviate oil seepage
into the creek. Contaminated areas of the site and features of the groundwater recovery
system were fenced to restrict public access.
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In October 1989 EPA granted MDHES the initial enforcement funding to conduct potentially
responsible party (PRP) noticing and administrative order negotiations and issuance. In
April 1990 MDHES signed an administrative order on consent with ARCO under which ARCO
agreed to conduct a remedial investigation and feasibility study (RI/FS) at the site.
In June 1990, ARCO began the RI/FS following the MDHES and EPA approved RI/FS work plan.
The remedial investigation complied with Superfund law, defined the nature and extent of
contamination and provided information to complete the baseline human health and
ecological risk assessments. The feasibility study included the development, screening
and evaluation of potential site remedies.
In June 1992, the USEPA proposed an additional removal action to control and recover the
light non-agueous phase liguid (LNAPL) (floating oils) identified during the RI. The
action included the installation of a 890 foot sheet piling on the south side of Silver
Bow Creek. The sheet piling is approximately 50 feet south of the creek. Ten recovery
wells were installed on site. Eight of the wells are located south of Silver Bow Creek
in a north/south line running perpendicular to the creek. Two wells are installed
parallel to the creek; one on each end of the sheet piling. The wells are approximately
25 feet deep. Each well has two pumps: one to collect free-floating oil and pump it to
an on-site storage tank and the other to pump contaminated groundwater to an on-site
granular activated carbon treatment facility built by EPA. The water treatment facility
went into operation January 22, 1993, at which time the system installed in 1985 was
shut down. In October, 1993, it is likely that EPA will implement limited soils
excavation as part of its removal response.
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
Public participation is reguired by CERCLA sections 113 and 117. These sections reguire
that before adoption of any plan for remedial action to be undertaken by the President
(EPA) or by a State (MDHES) or by anyone (PRPs), the lead agency shall:
1. Publish a notice and brief analysis of the Proposed Plan and make such plan
available to the public; and
2. Provide a reasonable opportunity for submission of written and oral comments and
an opportunity for a public meeting at or near the Site regarding the Proposed
Plan and any proposed findings relating to cleanup standards. The lead agency
shall keep a transcript of the meeting and make such transcript available to the
public. The notice and analysis published under item #1 shall include sufficient
information to provide a reasonable explanation of the Proposed Plan and
alternative proposals considered.
Additionally, notice of the final remedial action plan (Record of Decision) adopted
shall be published and the plan shall be made available to the public before commencing
any remedial action. Such a final plan shall be accompanied by a discussion of any
significant changes to the preferred remedy presented in the Proposed Plan along with
the reasons for the changes and a response (Responsiveness Summary) to each of the
significant comments, criticisms, and new data submitted in written or oral
presentations during the public comment period.
MDHES has conducted reguired community participation activities through presentation of
the Proposed Plan, a 60 day public comment period, a public hearing and presentation of
the selected remedy in the Record of Decision. Specifically included with the Record of
Decision is a Responsiveness Summary that summarizes public comments and MDHES
responses. The Record of Decision documents changes to the preferred remedy as a result
of public comments.
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The Proposed Plan for the Site was released for public comment on May 5, 1993. The
Proposed Plan was made available to the public in both the administrative record located
at the Montana Tech Library in Butte and at MDHES offices in Helena, MT, and information
repositories maintained at MDHES offices in Helena, the Montana Tech Library, the Butte
Public Library, the Butte EPA Office and the State Library in Helena. The Proposed Plan
was distributed to the MDHES Montana Pole Site mailing list. The notice of availability
of the Proposed Plan was published in the Butte-Montana Standard newspaper on May 7,
1993. A public comment period was initially designated from May 7, 1993 through June 7,
1993, but requests resulted in a 30 day extension to July 7, 1993.
A public hearing was held in Butte, Montana on May 27, 1993. At this hearing,
representatives from EPA and the MDHES answered guestions about problems at the Site and
the remedial alternatives under consideration as well as the preferred remedy. A
portion of the hearing was dedicated to accepting formal oral comments from the public.
A court reporter transcribed the entire hearing and MDHES made the transcript available
by placing it in the administrative record. A response to the comments received during
the public comment period is included in the Responsiveness Summary, which is part of
this Record of Decision. Also, community acceptance of the selected remedy is discussed
in section VII, Summary of Comparative Analysis of Alternatives, of the Decision
Summary.
IV. SCOPE AND ROIiE OF RESPONSE ACTION
The primary focus of the MPTP RI/FS was to evaluate findings of previous investigations,
to collect additional information to assist in characterizing current and future risks,
and to develop and evaluate long term and permanent remedial action alternatives. The
RI/FS was performed in accordance with the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP) 40 CFR Part 300, and CERCLA Section 104, 42 U.S.C. S
9604.
The overall objectives of the RI/FS were:
IX. To collect information on the types, concentrations, extent and movement of
contaminants present in subsurface soils, surface soils, surface water, sediment,
groundwater, oils, sludges, and dismantled equipment at the site;
X. To provide information for estimating the volume of contaminated media and
materials;
XI. To provide information on site physical characteristics and site contaminants for
use in the Risk Assessment, the Feasibility Study, and the Remedial Design;
XII. To collect data for use in treatability studies during the FS and RD;
XIII. To collect data on geotechnical properties for use in designing and locating
remediation structures during the RD;
XIV. To identify potentially applicable or relevant and appropriate regulations
(ARARs) for response actions; and
XV. To identify and evaluate remedial alternatives to address human health and/or
environmental risks.
Based on the evaluation of the wood treating operations, findings of previous
investigations and the results of the RI field investigation, the sources and the areas
of environmental contamination at the Montana Pole site have been adequately delineated.
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The remedy outlined in this Record of Decision represents the final remedial action at
the site and will address the principal threats to human health and the environment
which are posed by the contaminated media and materials.
V. SUMMARY OF SITE CHARACTERISTICS
The following section discusses the principle contaminants of concern found at the site,
summarizes the nature and extent of site contamination, provides a brief discussion of
contaminant fate and transport at the site and provides estimated volumes of
contaminated materials at the site.
Principle Contaminants of concern
Hazardous substances that have been released at or from the Site, but are not limited
to, include the following:
Pentachlorophenol and other chlorinated phenols
A mild acid with an hydroxyl group, pentachlorophenol (PCP) is a hazardous substance as
defined by CERCLA S 101(14). Pentachlorophenol ionizes in solution to form
pentachlorophenate anion. The pH dependent ionization leads to higher solubility for
pentachlorophenol than its normal agueous solubility of 14.0 mg/L. Once
pentachlorophenol dissolves in water, its adsorptive behavior begins to control its
fate. As agueous solubility decreases, the adsorption increases. Groundwater pH is
generally in the neutral range at the Site, rendering pentachlorophenol more mobile in
groundwater than the other contaminants of concern. Site aguifers are comprised of
fairly transmissive sands and gravels, resulting in rapid migration of
pentachlorophenol.
Pentachlorophenol is known to be biodegradable under both aerobic and anaerobic
conditions. Anaerobic degradation rates are generally 10 to 100 times slower than
aerobic degradation; therefore, if remediation time is critical, a method of oxygen
enhancement is recommended (Woodward-Clyde, 1988). Other related chlorinated phenols
have been identified at the Site. Chlorinated phenols are present in pentachlorophenol
as manufacturing byproducts. They may also result from breakdown of pentachlorophenol.
Pentachlorophenol is identified as a probable human carcinogen.
Polynuclear aromatic hydrocarbons
Several polynuclear aromatic hydrocarbons (PAHs), defined as hazardous substances by
CERCLA S 101(14), have been identified at the Site. These include: anthracene,
benzo(a)pyrene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene,
dibenzo(a,h)anthracene, indeno(c,d)pyrene, benzo(g,h,i)perylene, phenanthrene, chrysene,
fluoranthene, fluorene, naphthalene and pyrene. The majority of the compounds do not
contain active functional groups and have low agueous solubilities. The low molecular
weight PAHs are comparatively more soluble in water than high molecular weight PAHs and
have lower organic carbon partition coefficients. Low molecular weight compounds are
typically more mobile in the environment than the high molecular weight PAHs.
PAH compounds are known to be biodegradable under both aerobic and anaerobic conditions.
The rate of transformation of PAH compounds by soil microorganisms is related to the
compound's molecular weight as well as the acclimation of the soil microbes to the PAH
compounds. Thus, the low molecular weight PAHs biologically degrade at a faster rate
than the high molecular weight PAHs. The four and five ringed PAHs found at the Site
are suspected probable human (B2) carcinogens. The two and three ringed PAHs found at
the Site are not probable human carcinogens; however, they can present noncarcinogenic
health hazards.
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Polychlorinated cLLbenzo-p-dioxins and Polychlorinated dibenzofurans
Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are
hazardous substances as defined by CERCLA S 101(14). PCDDs and PCDFs are a family of
aromatic compounds that are often byproducts of chemical manufacturing or combustion
processes involving chlorinated organic compounds and heat.
The biological degradation rate of these compounds is generally very slow when compared
to other organic compounds. Because PCDDs and PCDFs have very low vapor pressures, they
do not readily evaporate or volatilize to the atmosphere. The compounds adhere tightly
to soil particles and do not migrate readily or leach into groundwater or surface water
unless the contaminated soil particles themselves migrate via erosion processes
(Freeman, 1989). This family of compounds includes suspected probable human carcinogens
of varying toxicity. One isomer, 2,3,7,8-tetrachlorophenol dibenzo-p-dioxin (TCDD), has
been determined to be the most toxic. Concentrations of the other less toxic isomers are
multiplied by toxicity eguivalence factors to determine their risk relative to
2,3,7,8-TCDD. The toxicity eguivalence for each PCDD and PCDF analyzed for a sample is
added together to result in one concentration value and the summation is expressed as
TCDD toxicity eguivalence (TE) which is used as the basis for determining overall health
risks from these compounds.
Summary of Nature and Extent of Contamination
As reported in the Final RI Report (ARCO, 1993a), seven different media were sampled
during the RI for the MPTP site. These media include: soils (surface, subsurface, and
removed), groundwater, surface water, sediments, process eguipment, miscellaneous oils,
and miscellaneous sludges. The samples were typically analyzed for PCP, PAHs, total
petroleum hydrocarbon (TPH), volatile organic compounds (VOCs), dioxins/furans, and
metals. The removed soils and miscellaneous oils and sludges were also analyzed using
the TCLP method for metals and organics.
Elevated levels of PCP, PAHs, TPH, and dioxins were detected in the surface and
subsurface soil samples collected from the plant process area and within and near the
historical drainage ditch. Figure 3 presents PCP surface soil concentrations greater
than 15,000 ug/kg. Figure 4 presents PCP subsurface soil concentrations above 10,000
ug/kg. Figures 5 through 8 present PCP subsurface soil boring concentrations in cross
section. The maximum concentrations of PCP, TPH, and dioxins detected in the surface
soil samples were 1,510,000 ug/kg, 71,500 mg/kg, and 8.18 ug/kg, respectively. The
maximum concentrations of PCP, PAH, TPH, and dioxins detected in the subsurface soil
samples were 1,160,000 ug/kg, 2,304,320 ug/kg, 55,600 mg/kg, and 11.36 ug/kg,
respectively. Elevated levels of PCP and PAH were generally found to depths of 8 feet
in the northern portion of the site and to depths greater than 15 feet in the southern
portion of the site. PCP, PAH, and TPH were detected in surface soil samples collected
from the former eastern and western wood storage yards at relatively low concentrations.
PCP, PAH, and TPH were not detected in subsurface soil samples collected in the wood
storage yards. The maximum concentrations of PCP, PAH, TPH, and dioxins detected in the
removed soils were similar to the maximum concentrations detected in the surface and
subsurface soils.
Figure 9 illustrates the approximate lateral extent of groundwater, LNAPL and surface
water contamination associated with the MPTP site. PCP in the groundwater is fairly
widespread throughout the site. Figures 10 and 11 show PCP concentrations detected in
groundwater samples taken at and near the site. Figure 12 illustrates the estimated
lateral extent of site PCP groundwater contamination at concentrations greater than 1
ug/1. LNAPL was detected in eight of the 39 wells sampled, although not all wells are
screened at a depth that would allow LNAPL to be measured. The maximum LNAPL thickness
measured during the RI was 2.2 feet in well W-8 which is located north of the pole
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barns. LNAPL thickness and the estimated extent of LNAPL contamination is shown in
Figure 13. Only floating woodtreating product was found during the RI. No dense
non-agueous phase liguids (DNAPLs) were found.
PCP, PAH, and TPH were detected in the surface water and sediment samples collected near
the oil seep locations on Silver Bow Creek. Figure 14 shows PCP, PAH and TPH surface
water concentrations in Silver Bow Creek. Figure 15 shows PCP, PAH and TPH sediment
concentrations in Silver Bow Creek. The maximum concentration of PCP detected in the
surface water samples (591 ug/1) was from the sample collected near the farthest
downstream seep. The maximum concentration of PCP detected in the sediment samples
(1,820 ug/kg) was from the sample collected immediately downstream of the farthest
downstream seep.
Metals (i.e., arsenic, cadmium, chromium, copper, lead, and zinc) were detected in soil,
groundwater, surface water and sediments at the site. Elevated metals concentrations
were generally found in association with Silver Bow Creek and tailings deposits near the
creek. Elevated metals concentrations are considered to be related to historic mining
activities in the vicinity of the site rather than any activities associated with the
site.
Minimal wipe sampling was performed on the process eguipment. The maximum
concentrations of PCP, PAH, and 2,3,7,8-TCDD detected on the wipe samples (100 cm[2])
were 317 ug/wipe, 10.76 ug/wipe, and 7.19 ug/wipe.
Approximately 26,000 gallons of oils and sludges are stored on site (at the time the RI
was conducted) including oil recovered from the oil/water separator, oils treated by the
KPEG process, reagent sludge from the KPEG processing operation, and miscellaneous oils
and sludges presumably collected from various tanks used in the wood preserving
operations. Elevated concentrations of PAHs, and VOCs were detected in all the oil and
sludge samples. Elevated concentrations of PCP were detected in all but the KPEG
treated oils and reagent sludge samples. Low levels of PCDDs and PCDFs
were detected in all but the KPEG treated oils and reagent sludge samples.
Major Sources of Contamination from Historical MPTP Operations
Based on historical information about former MPTP operations and data gathered during
the RI, the major sources of contamination from historic MPTP operations are discussed
below and include:
XVI. Plant process area;
XVII. Wastewater discharge ditch including the former waste sedimentation pond;
and
XVIII. LNAPL plume.
Plant Process Area. Two retorts and two butt treatment vats were located within the
plant process area, and spillage of product from these facilities during MPTP operations
has been reported (see Final RI Report, Section 1.2.2). Surface and subsurface soil
samples from the plant process area indicate the presence of high concentrations of PCP
and PAH compounds. Some of the soils in this area are saturated with woodtreating
chemicals and petroleum carrier oils. In addition, PCP levels greater than 10,000 ug/1
have been detected in groundwater beneath this area of the site, and an LNAPL layer is
present on the water table. Wastewater Discharge Ditch Area. Wastewater from the wood
treating process was discharged into on-site sedimentation pond(s) and an on-site
drainage ditch. PCP mixed with petroleum (PCP/oil) was used to treat timber during the
time these discharges occurred.
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The drainage ditch flows northward through the site toward Silver Bow Creek (see Figure
2). Soil was excavated from portions of the ditch to a depth of up to 6 feet as part of
EPA's removal actions. Sampling conducted during the RI indicates that soils and
groundwater beneath the drainage ditch are heavily contaminated throughout its length.
Depth to groundwater varies along the length of the drainage ditch. Groundwater is
about 20 feet below grade near Greenwood Avenue; about 8 feet below grade beneath the
interstate; and at about 2 to 4 feet below grade near Silver Bow Creek.
LNAPL Plume. As shown on Figure 13, an LNAPL plume consisting of PCP dissolved in
petroleum carrier oils, extends from the former process area to Silver Bow Creek. The
LNAPL is a result of former MPTP waste disposal practices and spillage of woodtreating
chemicals. The RI indicated that LNAPL is discharging to Silver Bow Creek at several
seep locations, and chemicals of concern are dissolving into groundwater from the LNAPL
plume. No DNAPLs were found at the site.
Conceptual Model of Contaminant Fate and Transport
A conceptual model was developed and presented in the final RI report and provides an
overview of site contaminant fate and transport as it existed during the RI (Figure 16).
The conceptual model describes the relationship between source areas, migration
pathways, and potential receptors. PCP, PAHs, dioxins, and furans at the MPTP site have
entered the environment from several source areas by spillage, leaks, or infiltration
and have migrated via various transport pathways (e.g., advective flow with the
groundwater). A detailed discussion of the chemical and biological processes and an
estimate of the rates of migration of different contaminants in the subsurface are
presented in the Final RI Report (ARCO, 1993a).
Estimated Volumes of Contaminated Materials
In the Final FS Report (ARCO, 1993b), estimates were made of contaminated site soils,
groundwater, LNAPL, oils, sludges, equipment and debris. The agencies believe that these
estimates were adequate for the purposes of the FS and remedy selection. However, it is
recognized that more accurate volume estimates may be required for remedial design.
Site Soils
The estimated volumes of contaminated site soils at the site are shown in Table 1.
These volumes include previously removed soils that are stored in pole barns at the
site, in place contaminated soils, and uncontaminated soils which would require removal
to access underlying contamination. Figures 17 and 18 show the locations of the in place
contaminated soils at the site.
Volumes estimates were developed:
XIX. considering the remedial alternatives developed;
XX. using PCP as an indicator compound;
XXI. using the PCP Preliminary Remedial Action Goal of 3 mg/kg;
XXII. using physical parameters, as discussed below, for determining the location and
accessibility of these contaminated soils.
PRAGs were developed based on information developed in the Baseline Risk Assessment and
are presented in Table 2. DHES found little difference in soil volumes estimated for
the 3 mg/kg PRAG and the 34 mg/kg PRAG. This may be because soil contamination at the
MPTP site is generally associated with contact with wood treating chemical solutions and
PCP concentrations in soils were generally found well above 3 mg/kg or well below 3
mg/kg.
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The volume of previously excavated soils presently stored on site is approximately
10,000 yd[3]. Volume estimates of soils removed near Silver Bow Creek and soils removed
for installation of a groundwater treatment system were estimated for use under various
remedial approaches. It is estimated that about 6,000 yd[3] of soils near the creek
would require excavation and treatment. This volume calculation assumes all the soils
north of the sheet piling installed by USEPA in September 1992 would be
excavated to a depth of 4 feet below grade. The volume of soils estimated to be
excavated during installation of the groundwater extraction and treatment system is
approximately 7,000 yd[3].
Volume estimates of additional contaminated in-place site soils include surface soils
and subsurface soils including soils impacted along the LNAPL plume. Areas where
contamination was found above the 3 mg/kg PCP PRAG in surface soils but not in
subsurface soils are shown in Figure 17 and consist of "hot spot" areas in the east and
west treated wood storage yards and soils near the former process area. The volume of
these soils is assumed to extend from the ground surface to 3 feet below ground surface
and is estimated to be 10,000 yd[3]. The actual depth of contamination in these areas
will be determined during the remedial action.
Areas where contamination was found above the 3 mg/kg PCP PRAG in both the surface and
subsurface soils, down to the groundwater table are shown in Figure 17. This includes
the former process area, the former waste water drainage ditch running from the process
area to Silver Bow Creek and areas adjacent to the drainage ditch on the north side of
the interstate. The volume of soils in these areas is estimated to be 82,000 yd[3].
This volume assumes that contaminated subsurface soil concentrations above PRAGs extend
to approximately 4 feet below the groundwater surface. This depth is based on the RI
data which showed that subsurface contamination above the 3 mg/kg PCP PRAG extends
approximately 4 feet below groundwater in these areas and other areas affected by the
LNAPL plume. The volume of these soils located beneath the highway is estimated at
4,000 yd[3].
In other areas of the site subsurface soils have been impacted by the floating LNAPL
layer. This area of LNAPL influence extends from the former process area to Silver Bow
Creek. LNAPL volume of 370,000 gallons has been estimated based upon the inferred LNAPL
plume shown in Figure 13. The extent of the inferred LNAPL plume is based on the
presence of LNAPLs in a number of wells and borings on the site. Within this area, a
"smear zone" where LNAPL has contacted subsurface soils near the groundwater table has
been estimated to extend vertically 2 feet above and 4 feet below the groundwater
surface. Contaminated subsurface soils associated with the LNAPL plume in this area
underlie uncontaminated soils. The volume of these uncontaminated soils have also been
estimated and are presented on Table 1. In order to excavate contaminated soils
associated with the LNAPL plume, the overlying soils would also require excavation.
Separation of clean and contaminated soils during the remedial action would be important
to minimize the volume of soils requiring treatment. Excavation of soils beneath the
interstate highway is considered to be infeasible. Contaminated soils beneath the
highway will be left in place and addressed by other methods.
The volume of accessible contaminated subsurface soils associated with the LNAPL plume
is estimated at 93,000 yd[3]. This volume is in addition to the 82,000 yd[3]
surface/subsurface volume estimate. The volume of contaminated subsurface soils
associated with the LNAPL plume which are considered inaccessible beneath the highway is
estimated at 37,000 yd[3]. This volume is in addition to the 4,000 yd[3] within the
drainage ditch beneath the highway. The volumes of uncontaminated soils overlying the
LNAPL plume are estimated to be 28,000 yd[3] in the area north of the highway and 66,000
yd[3] in the area south of the highway.
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Groundwater
The areal extent of contaminated groundwater above the MCL for PCP of 1 ug/L is
estimated to be 1.8 million sguare feet. Assuming an average aguifer thickness of 22
feet and a porosity of 30 percent, the total volume of alluvial groundwater contaminated
above the MCL was estimated to be approximately 90 million gallons. This volume
represents the volume of groundwater contaminated above the MCL in place. This value is
substantially lower than the volume that would be treated by a pump-and- treat system.
Equipment and Debris
A rough estimate of the volume of eguipment and debris on site was performed for the FS.
It is estimated that there is about 9,100 cubic yards of debris on-site which consists
of wood, soil cuttings, concrete, steel, and brick. A sampling program should be
undertaken as part of remedial design to determine more accurately the volume of debris
and extent of contamination prior to disposal.
Oils and Sludges
Approximately 6,300 gallons of untreated oily wastes from the oil/water separator
process; 9,000 gallons of KPEG-treated oil; 2,200 gallons of KPEG-reagent sludge; and
3,000 gallons of miscellaneous oily wastes and sludge are estimated to be stored in
drums and storage tanks at the MPTP site (ARCO, 1993a). Keystone (1991a) assumed that
the total guantity of oily wastes and sludge reguiring remediation was approximately
26,500 gallons. Additionally, it is estimated that between 3,000 and 6,000 gallons
of oily wastes would be generated each year in the first few years of operation of a
combined groundwater and LNAPL recovery system likely to be used for this site. The
guantity of LNAPL recovered from the groundwater systems annually will decrease over
time.
VI. SUMMARY OF SITE RISKS
The Baseline Risk Assessment (CDM, 1993) provides the basis for taking action and
indicates the exposure pathways that need to be addressed by the remedial action. It
serves as the baseline for indicating what risks could exist if no action were taken at
the Site. This section of the Record of Decision reports the results of the Baseline
Risk Assessment conducted for this Site.
As part of the remedial investigation and feasibility study, human health and ecological
risk assessments, which together comprise the Baseline Risk Assessment, were developed
to help MDHES and EPA determine actions necessary to reduce actual and potential risks
from hazardous substances at the Site. Risk assessments were conducted at the Site with
the following objectives:
XXIII. provide an analysis of baseline risk (potential risk if no remedy occurs)
and help determine the need for action;
XXIV. provide a basis for determining cleanup levels (concentrations) that are
protective of public health and the environment;
XXV. provide a basis to compare potential public health and ecological impacts
of various cleanup alternatives; and
XXVI. provide a consistent process to evaluate and document potential public
health and ecological threats at the Site.
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The Baseline Risk Assessment indicates that the principal threats stem from contaminated
groundwater, releases of contaminated groundwater and oily wood treating fluids into
surface water, and surface soils. The primary human health risk exposure pathways are
ingestion of and direct contact with contaminated groundwater and ingestion of or direct
contact with soils. Potentially affected receptors include residents, workers,
trespassers, recreational users, and terrestrial and aguatic biota.
Human Health Risks
The Baseline Risk Assessment indicates that there are excessive human health cancer
risks and excessive non-cancer health hazards associated with hazardous substances at
the Site. Remedial action is reguired in order to reduce these potential risks.
Contaminants of Concern for Human Health
Chemicals detected on the Montana Pole site were screened as based upon their toxicity
to humans or laboratory animals (when human data were unavailable), their maximum
concentrations measured in each media, and their freguency of detection. The same
screening criteria applied to soil and groundwater were also applied to surface water
and sediment. This made the screen very conservative for these media, since it is
unlikely that exposures to either surface water or sediment would occur over an extended
time period on a daily basis.
Based on the above described process and some special considerations, the chemicals
listed in Table 3 are considered contaminants of concern (COCs) for human health for the
Montana Pole site.
Exposure Assessment
Potential pathways by which human receptors could be exposed to contaminants at, or
originating from, the Montana Pole site are provided in Tables 4 and 5, and include
incidental exposure to soil, surface water and sediment, use of groundwater for domestic
purposes and consumption of vegetables grown in contaminated soils. In identifying
potential pathways of exposure, both current and likely future land use of the site and
surrounding study area were considered. Proximity to Silver Bow Creek and lack of
access control for much of the site suggests that trespassers may freguent the site and
be exposed to contamination. Past industrial use of the site suggests that future on
site workers might be exposed to site-related contaminants while at work. Finally, past
and present residential land use and zoning allowances suggest the potential for future
residential development. DHES recognizes that efforts are being pursued by ARCO and
Butte-Silver Bow government to further restrict land use at the site.
The assumptions used to estimate potential exposure for workers, trespassers and
residents are shown in Tables 6 through 14. Exposure point concentrations for surface
soils are shown in Table 15, for groundwater are shown in Table 16 and for surface water
and sediments are shown in Table 17. The highest exposures were estimated for future on
site residents, as expected, because such individuals are expected to contact
contamination more freguently than either workers or site trespassers. For residents,
exposure via the groundwater pathway is much greater than for any other pathway.
Potential future use of the alluvial aguifer for domestic purposes represents the
highest exposure potential for the site. Chemicals for which exposure is highest
include pentachlorophenol (PCP), the major wood-treating chemical used on site, and PAHs
which are constituents of creosote. Creosote was also used to treat wood at the Montana
Pole site for a brief period.
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Toxicity Assessment
The purpose of the toxicity assessment was to examine the potential for each chemical to
cause adverse effects in exposed individuals and to provide an estimate of the
dose-response relationship between the extent of exposure to a particular contaminant
and adverse effects. Adverse effects include both noncarcinogenic and carcinogenic
health effects in humans.
Carcinogenic Effects. Of the COCs for the site, several, including PCP, dioxins/furans,
2,4,6-trichlorophenol, some PAHs and arsenic, are known or suspected human carcinogens.
The most potent of these chemicals are the dioxins/furans. Some of the PAHs are also
relatively potent carcinogens, though less so than the dioxins/furans. PCP, for which
site-related exposures may be greatest, is a less potent carcinogen than either
dioxins/furans or the carcinogenic PAHs.
Noncarcinogenic Effects. The potential for COCs to produce noncancer effects varies
widely. Dioxins/furans are extremely potent compounds, and only small exposures may be
associated with increased risk of adverse effects. Other compounds, such as copper, are
relatively non-toxic, and only produce adverse effects at much higher exposure levels.
In general, exposures estimated in this assessment for noncarcinogenic effects are
sufficiently low such that only the more potent toxicants could present a significant
risk.
Risk Characterization
Cancer Risk Estimates. To evaluate potential cancer health risks related to the Montana
Pole site, chemical exposures calculated are multiplied by cancer slope factors to
develop upper range incremental lifetime cancer risks. Incremental cancer risks in the
range of 10[-6] or less may be characterized as acceptable by the EPA depending on the
nature of the site and the COCs.
Cancer risks for exposure to COCs in groundwater are the greatest for any pathway. Only
future residents are evaluated for this exposure (see Table 18). Risks exceed 1 x
10 [-2], the upper limit for risk predictions using current models. Significant risk is
attributable to PCP, even though this chemical is one of the least potent carcinogens
among the COCs. This finding attests to the very high concentrations of PCP found in
the groundwater beneath the Montana Pole site. Dioxins/furans also contribute
significantly to risks. These compounds are expected contaminants of technical grade PCP
which is used for wood treating.
The consumption of homegrown produce also contributes significant potential risk for
future residents (Table 18). Risks for this pathway, however, may be only about 1
percent of the risks from drinking contaminated groundwater. This is due to a reduction
in exposure concentration for most COCs (produce concentrations are estimated to be less
than soil concentrations), and fewer days of exposure (the growing season in Butte is
limited by climate). Risks from exposure to PCP and dioxins/furans are the greatest for
this pathway (risks of 9 x 10[-4] and 1 x 10[-4], respectively) for the southern area of
the site. Exposures in the northern area, between the Interstate and Silver Bow Creek,
had similar overall cancer risk estimates, although the risks for individual compounds
varied somewhat.
Risks associated with direct contact with soil (incidental ingestion and dermal contact)
are significantly less for all exposure scenarios than those estimated for groundwater
and produce consumption. However, for workers and trespassers, these pathways are major
contributors to overall risks, since groundwater and produce ingestion are not
considered (Tables 19 and 20). Overall, cancer risk estimates for workers and
trespassers are up to one thousand times less than those for future residents, and fall
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within the EPA risk range of 10[-4] to 10[-6].
Noncarcinogenic Health Risks. To evaluate non-cancer health risks, chemical exposure is
compared to one of several types of toxicity criteria to determine if the exposure is
within a range of exposure which is unlikely to cause adverse health effects. The
potential for noncarcinogenic health effects is evaluated by dividing a
chemical-specific exposure level by a chemical-specific reference dose. The resulting
hazard index (HI) assumes that there is a level of exposure (RfD) below which it is
unlikely for even sensitive populations to experience adverse health effects. If the
GDI exceeds the RfD (i.e., HI>1), a potential for non-cancer health effects may exist.
The pattern for non-cancer risks is similar to that for carcinogenic risks. Risks are
greatest for future residents and for groundwater and produce ingestion pathways. For
groundwater, dioxins/furans, noncarcinogenic PAHs and PCP all have hazard indices (His)
exceeding unity (533, 75, and 22 respectively, Table 18). Risks for adverse effects,
which could include effects on the liver, kidneys, adrenal glands and other organs may
be significant for these compounds.
For produce ingestion, His for dioxins/furans are smaller, but still exceed one. For
example the HI for dioxins/furans is 6 (Table 18). However, because of a high estimate
for PCP absorption through plant roots, the HI for PCP is higher (64) for this pathway.
Only anthracene among the PAHs is
a COG for soil, and it is present in guantities too small to present significant risk.
The only other possible contributor to risk via this pathway is arsenic (HI=7).
For the direct soil contact pathways, risks (His) are substantially lower. For future or
current residents, His for all chemicals are less than one, and no increased risk for
adverse effects is anticipated. Noncancer risk estimates for workers and trespassers
are shown in Tables 19 and 20.
Ecological Risks
The ecological risk assessment (ERA) for the Montana Pole site evaluated the potential
for harm to terrestrial and aguatic populations following exposure to contaminants.
Silver Bow Creek is presently degraded by metals contamination and does not support a
viable fishery. The risk assessment concluded if Silver Bow Creek is remediated for
metals contamination the presence of site contaminants could inhibit the recovery of
aguatic populations (fish) in the stream.
Contaminants of Concern
From the list of chemicals expected to occur at the Montana Pole site, seven chemicals
or chemical groups are selected for evaluation in the BRA. These chemicals were:
XXVII. Polycyclic Aromatic Hydrocarbons (PAHs)
XXVIII. Pentachlorophenol (PCP)
XXIX. Dioxin/Furans
XXX. Arsenic
XXXI. Cadmium
XXXII. Copper
XXXIII. Zinc
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Potential Receptors
Aquatic Communities. Silver Bow Creek adjacent to the Montana Pole site and downstream
to the Warm Springs Ponds does not support a fishery population. Westslope cutthroat
trout (Oncorhynchus clarki lewisi) and bull trout (Salvelinus confluentus) are reported
to have once been caught in the vicinity of Butte prior to intensive mining activities.
Prior to 1975, severe mining-related pollution in much of the upper Clark Fork River
Basin drainage had rendered the system incapable of supporting a viable fishery.
Excessive metals deposits still prevent the establishment of a fishery in Silver Bow
Creek.
Benthic invertebrate communities and algae have re-established themselves within the
study area since the cessation of direct mine waste water discharges to Silver Bow
Creek. Mayflies, caddis flies, and stoneflies have been collected, although they
demonstrate low density and limited diversity. No known surveys on benthic communities
have been conducted within the study area since about 1984. The current density and
diversity of this aguatic community is unknown.
Terrestrial Communities. No terrestrial communities within the Montana Pole site were
identified as critical habitat or communities of special concern. No rare or endangered
plants were identified within the study area boundaries of the Lower Area One (LAO)
Operable Unit of the Silver Bow Creek NPL site, nor downstream of this study area.
Vegetation growing adjacent to Silver Bow Creek within the Montana Pole site is limited
to willows (Salix exigua) and grasses. Shrubs indicative of dry conditions are found
throughout the area.
Ecological Toxicity Assessment
Toxicity assessment is typically comprised of two elements. The first, hazard
identification, is intended to characterize the nature and extent of biota health
hazards associated with chemical exposures. The second, a dose -response assessment,
determines the relationship between the magnitude of exposure to a chemical and the
occurrence of adverse health effects. For the Montana Pole site, each chemical of
concern was evaluated for toxicity values for use in risk characterization.
Ecological Risk Characterization
The ecological risk evaluation is similar to human risk evaluation, in that exposure
assumptions and toxicological data are combined with site data to estimate risk.
However, nonhuman receptors vary greatly in physiology and behavior, and thus it is
difficult to quantify risk. Thus, the ecological risk assessment was a qualitative
discussion of potential risks and how these risks might affect biological receptors at
the Montana Pole site.
Risks to Aquatic Life. Metals and arsenic found in sediments and surface water in
Silver Bow Creek may be a primary reason for the lack of diversity and productivity of
the reaches of Silver Bow Creek adjacent to the site. Elevated concentrations of these
contaminants are considered a result of historical mining activity in the upper reaches
of the Silver Bow Creek drainage. The Montana Pole wood treating plant is not
considered to be a source of metals contamination in the area.
Dioxins/furans, PAHs and PCP have all been detected in surface water and/or sediments in
stream reaches adjacent to the Montana Pole site. A seep where groundwater and LNAPL
discharge into the creek was detected visually near the location of surface water
sampling station SW-05. Thus chemicals are currently being released to surface water,
and may pose a threat to aquatic life.
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The stress on the Silver Bow Creek system from inorganic contamination limits the
potential receptors for exposure to organic chemicals. In particular, the lack of fish
greatly shortens the aguatic food chain by eliminating higher trophic levels. Further,
lack of food sources (aguatic plants, insects and other invertebrates, small fish) make
upper Silver Bow Creek unattractive for larger animals such as migratory water fowl or
raptors. Under current conditions, it is unlikely that such animals would spend any
significant time in stretches of the creek near the Montana Pole site. Any impact of
organic contamination from the Montana Pole site should be considered potential,
especially when such impacts are due to hypothetical biomagnification of chemicals near
the top of the food web. However, once Silver Bow Creek has been remediated in
association with the heavy metals contamination, and the aguatic food chain is
re-established, there will be a potential threat associated with the organic chemicals.
It is therefore necessary to address both inorganic and organic contamination of the
Creek to once again establish aguatic life in the Creek.
Concentrations of PCP detected in surface water exceed both the acute (8.9 ug/1 at pH of
7.0) and chronic (5.6 ug/1 at pH of 7.0) ambient water guality criteria (AWQC). Water
concentrations of PCP measured as high as 591 ug/1 could limit the recovery of aguatic
life in the impacted stretch of the creek.
PAHs, including lower molecular weight compounds such as anthracene, pyrene and
naphthalene, are present only in low concentrations even at the area of the seep. The
highest concentration reported was 12.7 ug/L for acenaphthene. Acute and chronic
toxicity values for acenaphthene and many other PAHs are not available, however, the
concentration of PAHs in surface water at the Montana Pole site and downstream of the
site are below observed chronic toxicity values for aguatic organisms. Although
individual PAHs are not specifically addressed in this assessment, the generally low
concentrations found in surface water and sediments suggest that a more refined
assessment would reach similar conclusions. For this reason, PAHs are discussed only as
a group, even though individual members of the group vary considerably in their toxicity
to aguatic life.
Risks to Terrestrial Life. Because organic COG concentrations appear to diminish
rapidly with distance downstream from the Montana Pole site, potential future impacts
from Montana Pole site-related chemicals are likely to be limited to a short reach of
stream starting at the region of discharge of contaminated groundwater. Wildlife and/or
domestic animals using the downstream portions of the creek as a drinking water source
are not expected to be exposed to significant concentrations of organic COCs, unless
discharge of contaminated groundwater significantly increases.
Significant exposure of major wildlife species to surface water, sediments, and soils in
the impacted reach of the creek are also unlikely. The Montana Pole site is heavily
disturbed by past human activity, and is surrounded by residential housing, industrial
development, a cemetery and an Interstate freeway. The site is unlikely to be
attractive to wildlife, and larger animals (predators, deer, elk) are not expected to
use the site, or the adjacent reach of the creek.
VII. DESCRIPTION OF ALTERNATIVES
A brief description of the site cleanup alternatives the agencies considered in the
Feasibility Study report follows. The estimated present worth cost of each alternative
includes capital cost and annual operation and maintenance cost. Remedial action time
frames are limited to 30 years for analysis, even for those alternatives reguiring
perpetual operation and maintenance.
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The cleanup alternatives presented in the Feasibility Study report were developed before
EPA constructed the groundwater treatment system which came on line in January 1993.
Therefore the assumed design and costs of the alternatives do not incorporate the EPA
system in their design. However, the presence of the EPA system was addressed in the FS
and potential use of the system was considered. Utilization of the EPA groundwater
treatment system will reduce the overall costs (presented below) for the alternatives
which include groundwater treatment systems.
Alternative 1: No Action
Estimated present worth cost: $ 2,310,000 to $ 2,350,000
Implementation time: Not Applicable
Superfund law reguires that agencies consider the no action alternative. This
alternative is used as a baseline against which to compare the other alternatives.
Under Alternative 1, no further action (other than the EPA's removal actions currently
being conducted at the site) would be undertaken. Contaminated soils, oils, sludges,
eguipment and debris would remain on site. Contamination would continue to migrate and
impact groundwater and Silver Bow Creek. Only the current fence (installed as part of
EPA's removal actions) would limit trespasser access to the site. Existing
institutional controls would allow most types of land uses. The costs for the no-action
alternative are associated with maintaining operation of the existing groundwater
containment and treatment system and continued administration of institutional controls
for a period of 30 years. Actual costs and efforts associated with the no action
alternative would be incurred indefinitely beyond the 30year period.
Alternative 2: Additional Institutional Controls and Groundwater Monitoring Estimated
present worth cost: $ 3,270,000 to $ 4,400,000 Implementation time: 1 year
institutional control 30+ years operations and maintenance
This alternative would involve implementing institutional controls in an attempt to
limit human exposure to contaminants. Additional institutional controls, beyond those
currently in existence, would be implemented to further restrict the development of site
land. These controls could include deed restrictions that prevent residential
development and construction activities in contaminated areas and modifications to the
zoning laws and building codes. The zoning laws would have to be modified such that
certain land uses including kennels, stables and stockyards would be prohibited.
Building codes could be modified to restrict construction depths to less than the depth
of the water table. Only the current fence (installed as part of EPA's removal actions)
would limit trespasser access to the site.
The EPA's groundwater controls currently being conducted at the site would continue.
Contaminated soils, oils, sludges, eguipment and debris would remain on site.
Contamination would continue to migrate and impact groundwater and Silver Bow Creek.
This alternative would include monitoring of downgradient (the groundwater eguivalent of
downstream) and vertical migration of dissolved groundwater contamination and LNAPL.
The costs for Alternative 2 are associated with maintaining operation of the existing
groundwater containment and treatment system, implementation of additional institutional
controls, continued administration of institutional controls and site monitoring. Total
estimated costs for Alternative 2 assume that the action would only occur for a period
of 30 years. Because the site would continue to be contaminated and pose risks to human
health and the environment indefinitely, actual costs and efforts associated with
maintaining Alternative 2 would be incurred indefinitely beyond the 30-year period.
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Alternative 3: Soil Capping and Groundwater Containment and Treatment
ALTERNATIVE 3A:
XXXIV. Surface capping of contaminated soils;
XXXV. Treatment of previously removed soils and a limited amount of excavated
soils using on-site incineration;
XXXVI. Containment and treatment of groundwater and LNAPL;
XXXVII. Treatment of oily wastes, sludges, equipment and debris; and
XXXVIII. Groundwater monitoring and institutional controls
Estimated present worth cost: $ 34,620,000 to $ 60,130,000
Implementation time: 2 years - soils 30+ years - groundwater, operations and
maintenance
Under Alternative 3A, contaminated soils in the former wood processing area and along
the historic drainage ditch (see Figure 17) would be capped to prevent direct human
contact and reduce infiltration of precipitation through the contaminated soils.
Contaminated surface soil hot spots outside these areas would be excavated and
consolidated with soils in the process area prior to capping. The cap would cover an
area of approximately 170,000 sguare feet. (A football field is 57,600 sguare feet.)
Approximately 213,000 cubic yards of contaminated soils would remain in place under this
alternative.
Soils previously excavated during EPA's 1985 removal action (bagged soils), contaminated
soils excavated during construction of groundwater remediation facilities (e.g.,
collection trenches), and contaminated soils located near Silver Bow Creek and
downgradient of the groundwater collection system would be treated in an on-site
incinerator. The estimated volume of soil treated under this alternative is 23,000
cubic yards, which includes approximately 10,000 cubic yards of previously removed soils
plus approximately 13,000 cubic yards of excavated soils. Other soil actions which
would be necessary under Alternative 3A include filling excavated areas using treated
soils, surface grading and revegetation.
Under this alternative, oils and sludges currently in place at the site would be
incinerated on-site along with soils. LNAPL recovered by the groundwater system while
the incinerator was operating would also be incinerated. LNAPL recovered after on-site
incineration has been discontinued would be incinerated off-site. Contaminated debris
and equipment would be decontaminated and disposed of in an appropriately licensed
off-site landfill.
A groundwater containment and treatment system would be constructed to contain the LNAPL
and dissolved groundwater contaminant plumes and capture the contamination before it
discharges to Silver Bow Creek. This system would include an extensive network of
extraction and containment mechanisms (trenches, extraction wells, physical/hydraulic
barriers). Groundwater treatment above ground is assumed to consist of oil/water
separation, bioreactor treatment and carbon polishing. Other modes of treatment such as
UV/oxidation or granulated activated carbon (GAG) may be utilized instead of a
bioreactor depending on detailed design analysis and the ability to meet performance
standards. Treatment of contaminated groundwater would occur to the degree necessary to
meet applicable environmental standards and health-based criteria prior to discharge.
Additionally, an in-situ (in-place) bioremediation process would be implemented to
assist in long-term cleanup of groundwater and subsurface soils.
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Once site remediation has effectively contained the contaminated groundwater and LNAPL,
and releases to Silver Bow Creek have been effectively reduced or eliminated, it is
expected that natural biodegradation and attenuation would effectively reduce the levels
of organic contaminants in Silver Bow Creek, stream sediments and groundwater downstream
of the site. These natural mechanisms would be relied upon to address the low level
contamination found in this area.
The specific design of the groundwater system would take place during the remedial
design and remedial action phase of site cleanup. The groundwater extraction and
treatment system could utilize the groundwater treatment plant constructed at the site
by EPA. Groundwater and LNAPL in and around the site would be monitored to evaluate the
effectiveness of the recovery and treatment system. The same institutional controls
would be implemented as those discussed under Alternative 2.
Total estimated costs for Alternative 3A assume the action would only occur for a period
of 30 years. Since the site would continue to be contaminated indefinitely, actual
costs and efforts associated with site monitoring, enforcement of institutional controls
and operation and maintenance of the cap and the groundwater system would be incurred
indefinitely beyond the 30 year period.
ALTERNATIVE 3B:
XXXIX. Surface capping;
XL. Treatment of previously removed soils and a limited amount of excavated
soils using biological land treatment;
XLI. Containment and treatment of groundwater and LNAPL;
XLII. Treatment of oily wastes, sludges, equipment and debris; and
XLIII. Groundwater monitoring and institutional controls
Estimated present worth cost: $ 21,060,000 to $ 36,640,000
Implementation time: 3 years - soils 30+ years - groundwater, operations
and maintenance
Alternative 3B is the same as Alternative 3A except that soils would be treated using
biological land treatment and all oils and sludges would be incinerated off-site.
Biological land treatment is not expected to achieve the degree of treatment provided by
incineration; however, final contaminant levels are anticipated to be within allowable
levels. Design studies would be utilized to determine achievable treatment efficiencies
and identify any additional remedial actions which may be necessary in conjunction with
biological land treatment to ensure compliance with cleanup goals.
ALTERNATIVE 3C:
XLIV. Surface capping;
XLV. Treatment of previously removed soils and a limited amount of excavated
soils using soil washing;
XLVI. Containment and treatment of groundwater and LNAPL;
XLVII. Treatment of oily wastes, sludges, equipment and debris; and
XLVIII. Groundwater monitoring and institutional controls
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Estimated present worth cost: $ 27,720,000 to $ 43,780,000
Implementation time: 2 years - soils 30+ years - groundwater, operations and
maintenance
Alternative 3C is the same as Alternative 3A except that soils would be treated using
soil washing and all oils and sludges would be dechlorinated and incinerated off-site.
Residual fine soils from the soil-washing process which do not meet cleanup criteria
would be further treated in a bioslurry reactor. The volume of residual fine soils
reguiring further treatment is estimated at five percent of the total volume of treated
soils. As with biological land treatment, soil washing is not expected to achieve the
degree of treatment provided by incineration; however, it is anticipated that allowable
final contaminant levels will be met. Design studies would be utilized to determine
achievable treatment efficiencies and identify any additional remedial actions which may
be necessary in conjunction with soil washing to achieve cleanup goals.
Alternative 4: Partial Excavation and Treatment of Soils and Groundwater Containment
and Treatment
ALTERNATIVE 4A
XLIX. Excavation of contaminated surface and subsurface soils and treatment using
on-site incineration;
L. Treatment of previously removed soils using on-site incineration;
LI. Containment and treatment of groundwater and LNAPL;
LII. Treatment of oily wastes, sludges, eguipment and debris; and
LIII. Groundwater monitoring and institutional controls
Estimated present worth cost: $ 77,880,000 to $ 110,840,000
Implementation time: 5 years - soils 30+ years - groundwater, operations and
maintenance
Under Alternative 4A, accessible contaminated soils in areas where surface soil
concentrations are above cleanup levels and where contamination above cleanup levels
extends from the surface to the groundwater table (see Figure 17) would be excavated and
treated using an on-site incinerator. The areas of the site which would be excavated
and Alternative 4A correspond to surface soil hot spots, the former process area, the
waste water discharge ditch and contaminated soils located near Silver Bow Creek and
downgradient of the groundwater collection system. Bagged soils previously excavated
during EPA's 1985 removal action and contaminated soils excavated from construction of
groundwater remediation facilities (e.g., collection trenches) would also be treated in
an on-site incinerator. Excavation of surface soil hot spot areas would occur to a
depth of approximately three feet. Subsurface excavation would occur to a maximum depth
of four feet below the groundwater table. The estimated volume of soil excavated under
this alternative is 105,000 cubic yards. The estimated volume of soil treated under
this alternative is 115,000, cubic yards which includes the bagged soils. Other soil
actions which would be necessary under Alternative 4A include filling excavated areas
using treated soils, surface grading and revegetation.
Under Alternative 4A, approximately 124,000 cubic yards of contaminated soils would
remain in place. This includes areas beneath the interstate highway which are
considered inaccessible and subsurface soils located outside of the former process and
drainage ditch areas which are contaminated by LNAPL near the groundwater table (see
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Figure 13). These soils would be addressed through LNAPL extraction, soil flushing and
in-situ bioremediation.
Under this alternative, oils and sludges currently in place at the site would be
incinerated on-site along with soils. LNAPL recovered by the groundwater system while
the incinerator was operating would also be incinerated. LNAPL recovered after on-site
incineration has been discontinued would be incinerated off-site. Contaminated debris
and eguipment would be decontaminated and disposal of in an appropriately licensed
off-site landfill.
A groundwater containment and treatment system, similar to the Alternative 3 system,
would be constructed to contain the LNAPL and dissolved groundwater contaminant plumes
and capture the contamination before it discharges to Silver Bow Creek. This system
would include an extensive network of extraction and containment mechanisms (trenches,
extraction wells, physical/hydraulic barriers). Groundwater treatment above ground is
assumed to consist of oil/water separation, bioreactor treatment and carbon polishing.
Other methods of treatment such as UV/oxidation or granulated activated carbon (GAG) may
be utilized instead of a bioreactor depending on detailed design analysis and the
ability to meet performance standards. Treatment of contaminated groundwater would occur
to the degree necessary to meet applicable environmental standards and health-based
criteria prior to discharge. Additionally, an insitu bioremediation process would be
implemented to assist in long-term cleanup of groundwater and subsurface soils.
Remediation of the contaminated aguifer to drinking water levels is a goal of this
alternative.
Once site remediation has effectively contained the contaminated groundwater and LNAPL,
and releases to Silver Bow Creek have been effectively reduced or eliminated, it is
expected that natural biodegradation and attenuation would effectively reduce the levels
of organic contaminants in Silver Bow Creek, stream sediments and groundwater downstream
of the site. These natural mechanisms would be relied upon to address the low level
contamination found in this area.
The specific design of the groundwater system would take place during the remedial
design and remedial action phase of site cleanup. The groundwater extraction and
treatment system could utilize the groundwater system installed at the site by EPA.
Groundwater and LNAPL in and around the site would be monitored to evaluate the
effectiveness of the recovery and treatment system. The same institutional controls
would be implemented as those discussed under Alternative 2. Institutional controls may
be adjusted or removed as the remedial action progresses toward completion and site
conditions allow. Total estimated costs for Alternative 4A assume that the groundwater
action would only occur for a period of 30 years. Although groundwater aguifer
remediation to cleanup levels is a goal under this alternative, some source areas would
remain and be treated in place over the long term. Therefore, actual costs and efforts
associated with site monitoring, enforcement of institutional controls and operation and
maintenance of the groundwater system may be incurred beyond 30 years.
ALTERNATIVE 4B
LIV. Excavation of contaminated surface and subsurface soils and treatment using
biological land treatment;
LV. Treatment of previously removed soils using biological land treatment;
LVI. Containment and treatment of groundwater and LNAPL;
LVII. Treatment of oily wastes, sludges, eguipment and debris; and
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LVIII. Groundwater monitoring and institutional controls
LIX.
Estimated present worth cost: $ 24,780,000 to $ 47,570,000
Implementation time: 6 years - soils 30+ years - groundwater, operations
and maintenance
Alternative 4B is the same as Alternative 4A except that soils would be treated using
biological land treatment and all oils and sludges would be incinerated off-site.
Biological land treatment is not expected to achieve the degree of treatment provided by
incineration; however, allowable final contaminant levels are anticipated to be met.
Design studies would be utilized to determine achievable treatment efficiencies and
identify any additional remedial actions which may be necessary in conjunction with
biological land treatment.
ALTERNATIVE 4C
LX. Excavation of contaminated surface and subsurface soils and treatment using
soil washing;
LXI. Treatment of previously removed soils using soil washing;
LXII. Containment and treatment of groundwater and LNAPL;
LXIII. Treatment of oily wastes, sludges, equipment and debris; and
LXIV. Groundwater monitoring and institutional controls
Estimated present worth cost: $ 35,450,000 to $ 52,660,000
Implementation time: 3 years - soils 30+ years - groundwater, operations
and maintenance
Alternative 4C is the same as Alternative 4A except that soils would be treated using
soil washing and all oils and sludges would be incinerated off-site. Residual fine soils
from the soil washing process which do not meet cleanup criteria would be further
treated in a bioslurry reactor. The volume of residual fine soils requiring further
treatment is estimated at five percent of the total volume of treated soils. As with
biological land treatment, soil washing is not expected to achieve the degree of
treatment provided by incineration; however, it is anticipated that allowable final
contaminant levels will be met. Design studies would be utilized to determine
achievable treatment efficiencies and identify any additional remedial actions which may
be necessary in conjunction with soil washing.
Alternative 5: Total Excavation and Treatment of Soils and Groundwater Containment and
Treatment
ALTERNATIVE 5A
LXV. Excavation of all accessible contaminated soils and treatment with on-site
incineration;
LXVI. Treatment of previously removed soils using on-site incineration;
LXVII. Containment and treatment of groundwater and LNAPL;
LXVIII. Treatment of oily wastes, sludges, equipment and debris; and
LXIX. Groundwater monitoring and institutional controls
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Estimated present worth cost: $ 99,870,000 to $ 156,220,000
Implementation time: 8 years - soils 30+ years - groundwater, operations
and maintenance
Under Alternative 5A, all accessible contaminated site soils would be excavated and
treated in an on-site incinerator. This includes the areas identified under Alternative
4 in addition to subsurface soils impacted by LNAPL. These areas correspond to surface
soil hot spots, the former process area, the waste water discharge ditch and soil areas
near the groundwater table which have been impacted by LNAPL. Bagged soils previously
excavated during EPA's removal action would also be treated in an on-site incinerator.
Excavation in surface soil hot spot areas would occur to a depth of approximately three
feet. Subsurface excavation would occur to a depth of approximately four feet below the
groundwater table. Excavation of the soils impacted by the LNAPL is assumed to extend
from two feet above to four feet below the groundwater table. The estimated volume of
soil excavated under this alternative is 279,000 cubic yards which includes about 94,000
cubic yards of uncontaminated soil reguiring excavation to access underlying
LNAPL-impacted soils. The total estimated volume of soil treated under this alternative
is 195,000 cubic yards and includes the bagged soils. Other necessary activities would
include filling excavated areas using treated soils, surface grading and revegetation.
Under Alternative 5A, approximately 44,000 cubic yards of contaminated soils would
remain in place. This includes areas beneath the interstate highway which are
considered inaccessible. These soils would be addressed through LNAPL extraction, soil
flushing and in-situ bioremediation.
Under this alternative, oils and sludges currently in place at the site would be
incinerated on-site along with soils. LNAPL recovered by the groundwater system while
the incinerator was operating would also be incinerated. LNAPL recovered after on-site
incineration has been discontinued would be incinerated off-site. Contaminated debris
and eguipment would be decontaminated and disposed of in an appropriately licensed
off-site landfill.
A groundwater containment and treatment system would be constructed to contain the
dissolved groundwater contaminant plume and any residual LNAPL and capture the
contamination before it discharges to Silver Bow Creek. However, the groundwater
containment and extraction design for Alternative 5A would entail a less extensive
network of extraction and containment mechanisms (trenches, extraction wells,
physical/hydraulic barriers) than under Alternatives 3 or 4 because excavation of all
accessible source areas containing LNAPL would occur as part of this alternative.
Groundwater treatment above ground is assumed to consist of oil/water separation,
bioreactor treatment and carbon polishing. Other methods of treatment such as
UV/oxidation or granulated activated carbon (GAG) may be utilized instead of a
bioreactor depending on detailed design analysis. Groundwater treatment above ground
would occur to the degree necessary to meet applicable environmental standards and
health-based criteria prior to discharge. Additionally, an in-situ bioremediation
process would be implemented to assist in long-term cleanup of groundwater and residual
subsurface soil contamination. Remediation of the contaminated aguifer to drinking
water levels is a goal of this alternative.
Once site remediation has effectively contained the contaminated groundwater and LNAPL,
and releases to Silver Bow Creek have been effectively reduced or eliminated, it is
expected that natural biodegradation and attenuation would effectively reduce the levels
of organic contaminants in Silver Bow Creek, stream sediments and groundwater downstream
of the site. These natural mechanisms would be relied upon to address the low level
contamination found in this area.
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The specific design of the groundwater system would take place during the remedial
design and remedial action phase of site cleanup. The groundwater extraction and
treatment system could utilize the groundwater treatment plan installed at the site by
EPA. Groundwater and LNAPL in and around the site would be monitored to evaluate the
effectiveness of the recovery and treatment system. The same institutional controls
would be implemented as those discussed under Alternative 2. Institutional controls may
be reduced or lifted as the remedial action progresses toward completion.
Total estimated costs for Alternative 5A assume that the groundwater action would occur
for a period of 30 years. Although groundwater remediation to cleanup levels is
expected under this alternative, some inaccessible source areas (under the interstate
highway) would remain and be treated in place. Therefore, actual costs and efforts
associated with site monitoring, enforcement of institutional controls and operation and
maintenance of the groundwater treatment system for the inaccessible source areas (under
the interstate highway) may be incurred beyond 30 years.
ALTERNATIVE 5B
LXX. Excavation of all accessible contaminated soils and treatment using
biological land treatment;
LXXI. Treatment of previously removed soils using biological land treatment;
LXXII. Containment and treatment of groundwater and LNAPL;
LXXIII. Treatment of oily wastes, sludges, equipment and debris; and
LXXIV. Groundwater monitoring and institutional controls
Estimated present worth cost: $ 27,530,000 to $ 55,200,000
Implementation time: 11 years - soils 30+ years - groundwater, operations
and maintenance
Alternative 5B is the same as Alternative 5A except that soils would be treated using
biological land treatment and all oils and sludges would be incinerated off-site.
Biological land treatment is not expected to achieve the degree of treatment provided by
incineration; however, it is anticipated that allowable final contaminant levels will be
achieved. Design studies would be utilized to determine achievable treatment
efficiencies and identify any additional remedial actions which may be necessary in
conjunction with biological land treatment.
ALTERNATIVE 5C
LXXV. Excavation of all accessible contaminated soils and treatment using soil
washing;
LXXVI. Treatment of previously removed soils using soil washing;
LXXVII. Containment and treatment of groundwater and LNAPL;
LXXVIII. Treatment of oily wastes, sludges, equipment and debris; and
LXXIX. Groundwater monitoring and institutional controls
Estimated present worth cost: $ 48,080,000 to $ 78,180,000
Implementation time: 4 year - soils 30+ years - groundwater, operations and
maintenance
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Alternative 5C is the same as Alternative 5A except that soils would be treated using
soil washing and all oils and sludges would be incinerated off -site. Residual fine
soils from the soil washing process which do not meet cleanup criteria would be further
treated in a bioslurry reactor. The volume of residual fine soils reguiring further
treatment is estimated at five percent of the total volume of treated soils. As with
biological land treatment, soil washing is not expected to achieve the degree of
treatment provided by incineration; however, it is anticipated that allowable final
contaminant levels will be achieved. Design studies would be utilized to determine
achievable treatment efficiencies and identify any additional remedial actions which may
be necessary in conjunction with soil washing.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Section 300.430 (e) (9) of the NCP reguires that the agencies evaluate and compare the
remedial cleanup alternatives based on the nine criteria listed below. The first two
criteria overall protection of human health and the environment, and compliance with
ARARs are threshold criteria and must be met. The selected remedy must represent the
best balance of the selection criteria.
Evaluation and Comparison Criteria
Threshold Criteria
1. Overall protection of human health and environment addresses whether or not a
remedy provides adeguate protection and describes how potential risks posed
through each pathway are eliminated, reduced or controlled through treatment,
engineering controls or institutional controls.
2. Compliance with applicable or relevant and appropriate reguirements addresses
whether or not a remedy will comply with federal and state environmental laws
and/or provide grounds for invoking a waiver.
Primary Balancing Criteria
3. Long-term effectiveness and permanence refers to the ability of a remedy to
maintain reliable protection of human health and the environment over time once
cleanup goals have been met.
4. Reduction of toxicity, mobility and volume through treatment refers to the degree
that the remedy reduces toxicity, mobility and volume of the contamination.
5. Short-term effectiveness addresses the period of time needed to complete the
remedy, and any adverse impact on human health and the environment that may be
posed during the construction and implementation period until cleanup goals are
achieved.
6. Implementability refers to the technical and administrative feasibility of a
remedy, including the availability of materials and services needed to carry out
a particular option.
7. Cost evaluates the estimated capital costs, operation and maintenance costs and
present worth costs of each alternative.
Modifying Criteria
8. State agency acceptance indicates whether, based on its review of the
information, the state (MDHES) concurs with, opposes or has no comment on the
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preferred alternative. However, for this Site, MDHES is the lead management
agency and EPA is the support agency. As such, the State has identified the
selected remedy and EPA has concurred with and adopted that identification.
9. Community acceptance is based on whether community concerns are addressed by the
selected remedy and whether or not the community has a preference for a remedy.
Although public comment is an important part of the final decision, MDHES and EPA
are compelled by law to balance community concerns with all of the other
criteria.
Following is a summary of the agencies' evaluation and comparison of alternatives.
Additional detail evaluating the alternatives is presented in the Feasibility Study
report.
1) Overall protection of public health and the environment: Alternatives 1 and 2 are
not expected to provide adeguate protection of public health and the environment
because releases of and exposure to site contaminants remain uncontrolled.
Alternatives 3A through 5C, if properly implemented, could be protective of
public health and the environment. However, the degree of protection provided by
Alternatives 3A, 3B, and 3C is dependent upon effective long term maintenance of
the cap and the groundwater system. Alternatives 5A, 5B and 5C would provide the
greatest degree of protection of public health and the environment because all
accessible contaminated source materials would be removed and treated which
substantially reduces potential risks from future releases.
2) Compliance with applicable or relevant and appropriate reguirements (ARARs):
Alternatives 1 and 2 do not meet chemical-specific ARARs for groundwater or
surface water. Alternatives 3, 4 and 5 are expected to meet chemical-specific
ARARs for surface water, location-specific ARARs and action specific ARARs.
Achieving chemical-specific ARARs for groundwater is not likely under Alternative
3 because most source areas would remain in place. Achieving chemical-specific
ARARs in groundwater under Alternative 4 is uncertain because, although a large
volume of source material is removed, a substantial amount of source material
would remain in place and reguire long-term remediation. Achieving
chemical-specific ARARs for groundwater may be possible under Alternative 5 since
all accessible source areas are removed.
3) Long-term effectiveness and permanence: Alternatives 1 and 2 provide no
long-term effectiveness or permanence for reducing risks to human health and the
environment beyond those currently in existence at the site. Cleanup goals for
the site would not be achieved. Alternatives 3, 4 and 5 permanently address the
oils and sludges, contaminated eguipment and debris through treatment and
off-site disposal.
Excavated soils are most effectively and permanently treated by incineration under
Alternatives 3A, 4A, and 5A. Biological land treatment and soil washing under
Alternatives 3B, 3C, 4B, 4C, 5B, and 5C are not expected to be as effective as
incineration but would permanently reduce the levels of contamination to within
established risk ranges. in-situ bioremediation would be effective at treating residual
source and dissolved phase groundwater contamination under Alternative 5. in-situ
bioremediation would be less effective as applied to Alternatives 3 or 4 as substantial
amounts of high strength source material, not effectively treated by in-situ
bioremediation, would remain in place. Capping under Alternative 3 is subject to
deterioration over time and reguires long term maintenance. Containment and reliance
upon engineering and institutional controls to protect human health and the environment
do not provide the degree of permanence that removal and treatment of contamination
does.
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Groundwater containment and treatment systems under Alternatives 3, 4 and 5 could all be
effective for containing contaminated groundwater, limiting contaminant migration, and
reducing impacts to Silver Bow Creek to allowable levels. Under Alternative 3 the
groundwater system is expected to require operation and maintenance indefinitely, since
only minimal soil excavation and treatment is planned. Under Alternative 4 the overall
effectiveness of groundwater remediation is expected to be greater than under
Alternative 3, because a large volume of contaminated soils and associated LNAPL is
excavated and treated. Operation and maintenance of the groundwater system under
Alternative 4 is expected to be required for a shorter period of time than under
Alternative 3. Groundwater treatment under Alternative 5 is anticipated to have the
greatest effectiveness of the alternatives because all accessible contaminated soils and
LNAPL are excavated and treated. Under Alternative 5, operation and maintenance of the
groundwater system is expected to be required for a shorter period of time than under
either Alternative 3 or Alternative 4. Because Alternative 5 captures and treats the
greatest percentage of continuing sources of contamination, Alternative 5 provides the
greatest assurance of long-term effectiveness and permanence. It is technically
impracticable to remove more source material than is contemplated under Alternative 5.
4) Reduction of toxicity, mobility and volume: Alternatives 1 and 2 provide no
reduction of toxicity, mobility or volume through treatment beyond that provided
by the actions currently in place at the site. Alternatives 3, 4 and 5 reduce the
toxicity and volume of oils and sludges through either on-site incineration or
off-site incineration. The toxicity of contaminated equipment and debris is
reduced by decontamination under Alternatives 3, 4 and 5.
The toxicity, mobility and volume of contaminants in excavated soils is effectively
eliminated by incineration under Alternatives 3A, 4A and 5A. Biological land treatment
and soil washing under Alternatives 3B, 3C, 4B, 4C, 5B and 5C reduce the toxicity and
volume of contaminants in soils but not to the degree provided by incineration.
Alternative 3 provides minimal reduction of toxicity, mobility and volume of
contaminated site soil because a cap is employed. Alternative 4 provides a greater
reduction of toxicity, mobility and volume of contaminated site soil than Alternative 3
because a large amount of contaminated soils and associated LNAPL are excavated and
treated. Alternative 5 provides the greatest reduction of toxicity, mobility and volume
of contamination in soils of all the alternatives because all accessible contaminated
soils and associated LNAPL are excavated and treated.
Groundwater treatment systems included in Alternatives 3, 4 and 5, provide reduction of
toxicity, mobility, and volume of groundwater contamination. Alternative 4 provides
greater reduction of toxicity, mobility and volume of groundwater contamination than
Alternative 3 because large sources of groundwater contamination (contaminated soils and
LNAPL) are excavated and treated. Alternative 5 provides the greatest reduction of
toxicity, mobility and volume of groundwater contamination of all the alternatives
because all accessible sources of groundwater contamination (contaminated soils and
LNAPL) are excavated and treated.
5) Short-term effectiveness: Under Alternatives 1 and 2, there is potential for
workers and site visitors to be exposed to hazardous chemicals during
implementation of the current removal actions being performed by EPA at the site.
Adhering to safe work practices and using health and safety equipment is designed
to limit the exposure to workers and visitors to within allowable levels.
During implementation of Alternatives 3, 4 or 5 there is potential for workers, site
visitors, and nearby residents to be exposed to hazardous chemicals. Adhering to safe
work practices and using health and safety equipment should limit the exposure to
workers and visitors to within allowable levels. Dust and vapor release control
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activities can be implemented to limit this exposure potential. The incinerator used
under Alternatives 3A, 4A, and 5A can be designed to ensure emissions meet allowable
standards. Given this and the short duration that the incinerator would be on-site,
health risks to nearby residents would be low.
6) Implementability: Alternatives 1 through 5 are all technically implementable.
Capping source areas (Alternative 3) is likely easier to implement than removal
and treatment of source areas (Alternative 4 and 5). Excavation of saturated
soils is more difficult than excavation of soils above the water table. For
Alternatives 3, 4 and 5 the technologies for soil and groundwater treatment are
readily implementable and have all been used in full scale application at other
sites. Prior to full-scale implementation of any of these treatment technologies
at the site, design optimization studies are appropriate. On-site incineration
may not be acceptable to the local community and off-site incineration can be
difficult to implement because off-site incinerator operators are reluctant to
accept wastes containing dioxin. Under Alternative 3, cap maintenance and
operation and maintenance of the groundwater system will have to continue
indefinitely. Operation and maintenance of the groundwater systems under
Alternatives 4 and 5 may be reguired beyond 30 years.
7) Cost: Alternative 1 is the least costly to implement. Alternative 5A is the most
costly to implement. The 30-year present worth of Alternative 3 ranges from
$16.5 million to $36.4 million; Alternative 4 ranges from $18.8 million to $88.6
million; and Alternative 5 ranges from $22.5 million to $132.2 million.
Cost estimates provided for the FS showed above-ground biological treatment of soils to
be more cost effective than soil washing and incineration. Incineration is significantly
more expensive than either biological land treatment or soil washing. Design studies
could further define the relative costs of these treatment options.
Total estimated costs for all the alternatives assume that the action will only occur
for a period of 30 years. Under Alternatives 1, 2, and 3, since the site will continue
to be contaminated indefinitely, actual costs and efforts associated with remedial
actions would be incurred indefinitely beyond the 30 year period. Although the goal
under Alternatives 4 and 5 is to remediate the site in a finite period of time, the
actual costs and efforts associated with remedial actions, particularly groundwater
remediation, may be incurred beyond the 30 year period. Additionally, because the
estimated groundwater remediation costs under Alternatives 3, 4 and 5 include entire
system costs, utilization of the EPA groundwater treatment system would reduce the
estimated costs of groundwater remediation as presented here and in the feasibility
study report.
8) State agency acceptance: The State of Montana has been the lead agency for the
development of this Record of Decision and has selected a modified Alternative 5B
as the remedy contained herein. EPA has participated in the remedial process as
the support agency and has concurred with and adopted the remedy selection.
9) Community acceptance: Public comment on the Remedial Investigation, Feasibility
Study and Proposed Plan was solicited during formal public comment periods
extending from May 7, 1993 until July 7, 1993. Comments received from the
community indicate overwhelming support for the preferred remedy. Response to
the community comments are found in the Responsiveness Summary.
During the public comment period, MDHES and EPA received extensive comments from
Potentially Responsible Parties (PRPs) that have been identified for the Site. Comments
received from the PRPs indicated their opposition to the preferred alternative,
specifically to the goal of groundwater cleanup to drinking water standards. In initial
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comments, the PRPs preferred the approach of Alternative 3 which consists primarily of
soil capping and stressed that the most appropriate land uses at the site are industrial
or recreational. In comments received from some of the PRPs after the close of the
comment period, the PRPs suggested an approach based on a modification of Alternative
4B. PRP comments with MDHES and EPA responses are also found in the Responsiveness
Summary.
MDHES and EPA have carefully considered all comments, and have made some modifications
to the preferred remedy (Alternative 5B) which the agencies deem appropriate.
Modifications to preferred remedy are described in Section XI of this document.
IX. SEIiECTED REMEDY
Based upon consideration of CERCLA reguirements, the detailed analysis of alternatives,
and public comments, MDHES and EPA have determined that Alternative 5B, with some
modifications, represents the best balance of considerations using the selection
criteria and is the appropriate remedy for the site. This alternative will provide
maximum source reduction, remediate groundwater to the extent practicable and limit
releases to Silver Bow Creek to allowable levels. All accessible contaminated soils and
LNAPL will be excavated to the extent practicable and treated, preventing this material
from continuing to contaminate groundwater. The long-term effectiveness and degree of
permanence of the selected remedy is high. MDHES does not expect any unmanageable
short-term risks associated with this alternative. This remedy will comply with all
applicable or relevant and appropriate reguirements. This remedy uses treatment
technologies and permanent solutions to the maximum extent practicable and will be cost
effective. The selected remedy will also satisfy the preference for treatment as a
principal element of the remedy and for on-site remedies established in CERCLA. While
certain other alternatives may better satisfy certain individual selection criteria, the
selected remedy best meets the entire range of the selection criteria and achieves, in
the determination of both EPA and MDHES, the appropriate balance, considering site
specific conditions and the criteria identified in CERCLA and the NCP. The criteria
described above are discussed in more detail in Section X, Statutory Determinations,
below.
Components of Selected Remedy
The major components of the selected remedy include:
1. Excavation of contaminated soils from accessible areas of the site, to the extent
practicable. The volume of soils is estimated to be approximately 208,000 cubic
yards;
2. Treatment of excavated soils (208,000 cubic yards approximately) and previously
removed soils (10,000 cubic yards approximately) by above ground biological
treatment;
3. In-place biological treatment of contaminated soils below the depth of excavation
before backfilling;
4. Backfill of excavated and treated soils into excavated areas if possible, surface
grading and revegetation; 5. Soil flushing of inaccessible soils areas
(principally underlying Interstate 15/90) in order to recover hazardous
substances;
6. Containment of contaminated groundwater and LNAPL using physical and/or hydraulic
barriers (as determined during remedial design) in order to prevent the spread of
contaminated groundwater and LNAPL and to limit releases of contamination into
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Silver Bow Creek;
7. Treatment of extracted groundwater using the present EPA water treatment plant
(which consists of oil/water separation followed by granulated activated carbon
treatment). The ultimate design of the groundwater treatment system (as
determined during remedial design) may include the addition of biological means
or ultraviolet oxidation (UV/oxidation) to maximize cost effectiveness of the
treatment system. Treatment will meet standards for discharge or reinjection, as
appropriate;
8. Discharge of extracted, treated groundwater into Silver Bow Creek and/or
reinjection of extracted, treated groundwater into the aguifer (as determined
during remedial design);
9. Enhanced in-situ biological treatment of contaminated groundwater, inaccessible
contaminated soils areas and contaminated soils not recovered by excavation;
10. Treatment of contaminated site debris and eguipment by decontamination followed
by disposal of these materials in a licensed off-site landfill;
11. Treatment of contaminated oils and sludges in a licensed offsite incinerator;
12. Additional institutional controls preventing access to contaminated soils and
groundwater; and
13. Groundwater monitoring to determine movement of contaminants and compliance with
remedial action reguirements. Once site remediation has effectively contained
the contaminated groundwater and LNAPL, and releases to Silver Bow Creek have
been effectively reduced or eliminated, it is expected that natural
biodegradation and attenuation will effectively reduce the levels of organic
contaminants in Silver Bow Creek, stream sediments and groundwater downstream of
the site. These natural mechanisms will be relied upon to address the low level
contamination found in this area.
Estimated Costs of the Remedy
The total present worth cost of Alternative 5B was estimated by ARCO in the feasibility
study in the range of $27.5 million to $55.2 million. These costs are detailed in Table
21. The estimated cost of the selected remedy is expected to vary somewhat from that of
Alternative 5B as explained below.
Cost Uncertainties
The actual cost of implementing the remedy will be lower than the Alternative 5B
estimate because the groundwater treatment plant constructed by EPA will be utilized.
Additionally, ARCO did not fully account for soil flushing costs in the FS. ARCO has
provided those costs to DHES as shown in Table 22. The estimated 30 year present worth
cost for soil flushing under the interstate highway ranges from $328,000 to $612,000.
Subtracting the cost of the treatment facility, estimated between $981,000 and
$1,090,000, from the original cost estimate and adding the cost of soil flushing changes
the total present worth cost of the alternative to between $26.9 million to $54.7
million.
Furthermore, the agencies believe that the estimate of costs for this alternative as
presented by ARCO in the feasibility study report significantly overstate certain cost
elements. For example, the cost figure of $17.00 per yd[3] for excavation of soils can
be expected to apply only to a portion of the most difficult to excavate materials. The
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costs for most of the excavation should be under $9.00/yd[3]. For purposes of
comparison of alternatives, however, even the higher figure for this alternative is
used. For purposes of budgeting and planning, the agencies' best estimate of the cost
of this alternative is $26.9 million.
It is also recognized that operation and maintenance costs beyond the thirty year time
frame used in the FS, and the discount rate used to evaluate the present worth of
operation and maintenance costs are important considerations. DHES recognizes that the
use of a 7 percent discount rate used in the FS and calculation of present worth costs
without inclusion of inflation, tends to underestimate future costs. This also makes
the costs of remedies that rely more heavily on future actions such as operations and
maintenance for the bulk of site remediation appear less costly than capital intensive
remedies.
DHES firmly believes that, because Alternative 5 removes and treats a large volume of
source material while Alternative 3 does not, total remediation time under Alternative 5
is substantially less than under Alternative 3. Therefore, DHES believes the costs of
Alternative 5 beyond 30 years would be less than the costs of Alternative 3 beyond 30
years.
Some elements of the remedy will be further refined during remedial design. Specific
design and start-up testing will be necessary prior to implementation of the selected
remedy.
Cleanup Levels
Currently the Montana Pole site is zoned for industrial land use with residential use
allowed for owners and caretakers of businesses on the premises. However, it is possible
that the site will be restricted from any residential use in the future. The PRPs
indicated in comments submitted during the Proposed Plan comment period that they are
pursuing rezoning of this area, as well as creation of conservation easements and
possibly other institutional controls to preclude residential land use and groundwater
use at the site. Representatives of the Planning Office of Butte-Silver Bow County have
expressed a willingness to accommodate the PRPs' reguests and institute such land use
restrictions.
Accordingly, cleanup levels and the selection of the remedy are based upon an assumption
of adeguate institutional controls to prevent any residential use at the site. Soil
cleanup levels have been developed to protect recreational and industrial land users at
the site from excessive health risks. If, for any reason, appropriate land restrictions
are not actually implemented, cleanup goals will be adjusted accordingly.
Cleanup levels for site soils are listed in Table 23. These levels are based on a 1 in
1,000,000 cancer risk level for recreational land use at the site for each contaminant
of concern for the most susceptible exposure pathway. For example, the cleanup level
for PCP corresponds to a 10[-6] risk level via dermal exposure, while the cleanup level
for dioxins is based on a 10[-6] risk level via ingestion. These cleanup levels
correspond to total cancer risk of approximately 3.86 x 10[-6] when risks for all
contaminants of concern and all pathways are summed (see Table 24). These cleanup
levels have been set using the 10[-6] target to be protective. These cleanup levels
correspond to a total cancer risk of approximately 2.0 x 10 [-5] for industrial land use
as shown on Table 24.
The cleanup goals for site groundwater are shown on Table 25 and include maximum
contaminant levels (MCLs) and non-zero maximum contaminant level goals (MCLGs). For
those contaminants of concern for which MCLs or MCLGs do not exist, cleanup levels will
be based on a 1 in 1,000,000 cancer risk level or a 0.9 hazard index for ingestion of
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groundwater. Cleanup goals for groundwater must be met at the Point of Compliance,
which will be the management unit boundary, as defined below. These cleanup goals are
necessary even with planned institutional controls to ensure the contamination does not
spread, Silver Bow Creek is protected, and the NCP expectations for groundwater are met.
The cleanup levels for Silver Bow Creek are shown in Table 26 and are based on MCLs,
non-zero MCLGs and the Montana Water Quality Act Iclassification standard. One goal of
the groundwater remedial action is to contain and then remediate contaminated
groundwater in order to limit release of contaminants to Silver Bow Creek and reduce
contaminant levels in the creek to within applicable standards. Using the I-Class
methodology, instream contaminant concentrations at the Point of Compliance must be
reduced to the larger of either Gold Book levels or one-half of the mean instream
concentrations immediately upstream of the site. This takes into account that there may
be other sources of contaminants upstream of the site. However, as all sources of
contaminants are reduced or eliminated, instream contaminant levels from Montana Pole
sources will approach the Gold Book levels. Therefore the ultimate cleanup levels which
are to be achieved in the stream are Gold Book levels, MCLs and non-zero MCLGs as shown
on Table 26.
The cleanup levels for treated water discharges to Silver Bow Creek are also based on
MCLs, non-zero MCLGs and the I-Classification standard. The ultimate cleanup levels
which are to be achieved are shown on Table 27.
The cleanup levels for any water to be reinjected into the aquifer are based on
non-degradation criteria and must be no greater than the average concentration of
groundwater contamination in the area of recharge.
Points of Compliance
Compliance with cleanup levels described in Table 23 must be met for all excavated
soils. Other performance standards must be achieved for contaminated soils below the
depth of excavation or for soils not accessible to excavation (under the EPA water
treatment plant and under Interstate 1-15/90).
For groundwater, compliance with remediation levels must be achieved at the waste
management area boundary. Since the contaminated materials will be excavated, treated
to levels protective for soil standards, and returned to their place, some contaminated
material will effectively remain in place. In such a situation, EPA has determined that
"the remediation levels should generally be attained at and beyond the edge of the waste
management area." Preamble to the final NCP, 55 Fed. Reg. 8753 (March 8, 1990). This
boundary can effectively be defined as the edge of the excavated area, including any
additional area where contaminated material is not excavated for any reason. This
boundary is to be specifically delineated during remedial design/remedial action to
ensure that groundwater contamination does not migrate into uncontaminated areas. Along
Silver Bow Creek, this boundary is to be the south bank of the creek. Using this
boundary as the point of compliance for attainment of the groundwater remediation levels
is protective of any off-site groundwater uses and protective of the water quality goals
for the stream.
This point of compliance reflects the change from the Proposed Plan that results from
elimination of the possibility of future residential use at the site. Because impending
zoning changes and other institutional controls will prevent use of groundwater on the
site for drinking water purposes, it will not be necessary to attain the remediation
levels throughout the contaminated plume itself, as anticipated in the Proposed Plan.
If, however, appropriate changes and controls are not implemented, the point of
compliance should be viewed as throughout the plume, except the area under the
interstate, since any other location on the site would be a potential area for access to
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groundwater for drinking water purposes.
Surface water cleanup levels must be achieved at all points within Silver Bow Creek.
Upstream surface water measurements, needed for determination of the I-Class standard,
must be made upstream of all sources of contamination at the site. Additionally, any
runoff from the site to Silver Bow Creek, for example, from precipitation or snow melt,
must meet the same surface water standards identified for treated water discharge.
Runoff not meeting those standards must be captured and treated along with extracted
groundwater prior to discharge.
Performance Standards for Soils
For soils and sediments, the remedial goal is treatment so that the contaminant
concentration levels pose no unacceptable risk to human health or the environment.
Since no federal or state chemical specific ARARs exist for these media, cleanup levels
were determined for contaminants of concern through a site specific risk assessment.
The specific performance standards which will be used to ensure attainment of the
remediation levels for these contaminated media are:
LXXX. Excavation of accessible soils and associated LNAPLs with contamination levels in
excess of the cleanup levels specified in Table 23. Depth of excavation,
particularly at and below the groundwater table, will be based on field judgment
and technical practicability, as determined by the lead agency in consultation
with the support agency. LNAPLs at the groundwater table will be recovered to
the maximum extent practicable as determined by the agencies;
LXXXI. Soils below the depth of excavation with contaminant levels above cleanup
levels specified in Table 23 will be bioremediated in place. Biotreatment
may include nutrient addition via irrigation, and tilling on routine
intervals. After it has been determined by the lead agency, in
consultation with the support agency, that in place bioremediation of these
soils is no longer effective or practicable and contaminant levels have
plateaued, or it is determined by the agencies that these areas would be
effectively addressed by the in-situ bioremediation implemented under the
groundwater actions, these areas will be backfilled. Residual
contamination will be further treated by in-situ bioremediation as outlined
under Performance Standards for Groundwater;
LXXXII. Treatment of excavated and previously excavated soils to achieve cleanup
levels specified in Table 23. Soils excavated from near Silver Bow Creek
which contain tailings materials with elevated metals concentrations will
be biologically treated and disposed in an appropriate Butte mine waste
repository. All contaminated soils north of the active railroad bed are
considered tailings material;
LXXXIII. Backfill of treated soils into excavated areas if possible, filling of
remaining excavations with clean fill, replacement of all clean soils,
surface grading and revegetation or covering with suitable material
compatible with existing or future land uses;
LXXXIV. Remediation of inaccessible contaminated soils (consisting primarily of
those soils underlying Interstate 1-15/90 and any soils under the EPA water
treatment plant) by a two phased approach. First, enhanced LNAPL recovery
via extraction wells and recovery trenches using hydraulic gradients and
soil flushing to remove hazardous substances from these inaccessible soils.
Adjustment of pH, use of surfactants and other methods should be considered
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to maximize recovery of hazardous substances. After it has been determined
by the lead agency, in consultation with the support agency, that recovery
of hazardous substances from these areas by these methods is no longer
effective or practical and contaminant levels have plateaued, these areas
will be addressed by in-situ bioremediation as outlined under Performance
Standards for Groundwater;
LXXXV. Implementation of engineering and institutional controls during the
remedial action to prevent access to contamination and to limit the spread
of contamination; and
LXXXVI. Attainment of all ARARs identified in Appendix A for the remediation of
soils.
Sampling will be performed during the response action to verify that all soils
contaminated above the cleanup levels are treated. The sampling program shall be
developed during remedial design.
Performance Standards for Groundwater
For site groundwater, remediation goals provide maximum source reduction and protect
Silver Bow Creek and uncontaminated groundwater by minimizing migration of contaminants
with the groundwater. Cleanup levels for groundwater are MCLs and non-zero MCLGs
established by the Safe Drinking Water Act or risk based levels developed in the absence
of MCLs or MCLGs. Attainment of these cleanup levels at groundwater points of compliance
will be protective of human health and the environment and will ensure that
uncontaminated aguifers and adjacent surface waters are protected for potential
beneficial uses.
The specific performance standards which will be used to ensure attainment of the
remediation goals for groundwater are:
LXXXVII. Containment of contaminated groundwater and LNAPL using hydraulic and/or
physical barriers (as determined during remedial design) to effectively
prevent the spread of contaminated groundwater and LNAPL and limit releases
of contamination into Silver Bow Creek. Releases into Silver Bow Creek
must be reduced in order to achieve cleanup levels identified in Table 26
for Silver Bow Creek. Migration of contaminated groundwater must be limited
in order to maintain groundwater cleanup levels (Table 25) at groundwater
points of compliance;
LXXXVIII. Treatment of extracted groundwater to cleanup levels in Table 27 prior to
discharge to Silver Bow Creek. Control and treatment, if necessary, of any
contaminated runoff prior to discharge to Silver Bow Creek to meet the same
cleanup levels;
LXXXIX. Treatment of the contaminated groundwater aguifer and contaminated soils
not recovered by excavation by enhanced in-situ bioremediation. in-situ
treatment may include the reinjection of treated groundwater and the
addition of oxygen and nutrients to promote the biodegradation of
contaminants. in-situ treatment of the site groundwater will continue
until contaminant levels have plateaued and it is no longer effective or
practical to continue treatment, as determined by the lead agency in
conjunction with the support agency;
XC. Attainment of all ARARs identified in Appendix A for groundwater remediation;
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XCI. Monitoring of groundwater wells within or proximate to the contaminated
groundwater plume for contaminants of concern for groundwater; and
XCII. Implementation of institutional controls to prevent access to or impacts upon
contaminated groundwater at the site.
Groundwater sampling will be performed during the response action to verify that
contaminated groundwater above the cleanup levels is contained and treated. It is
anticipated that the treatment prescribed for sources of contamination at the site will
effectively reduce the levels of contamination and shrink the contaminant plume
sufficient to stabilize the site within a reasonable period of time.
Compliance Sampling Program
A sampling program for monitoring the remedial action and determining compliance with
the performance standards shall be implemented during the remedial action. In addition,
to ensure that groundwater performance standards are maintained, it is expected that
groundwater will be monitored at least twice annually during the groundwater seasonal
high and low for a period of at least three years following discontinuation of
groundwater remediation. These monitoring programs will be developed during remedial
design and shall include, at a minimum, the following: analytical parameters (focusing
on the contaminants of concern, but analyzing other contaminants, if any, that are not
contaminants of concern and are determined to be occurring at levels exceeding MCLs or
non-zero MCLGs), sampling points, sampling freguency and duration, and statistical
methods for evaluating data. Specific performance monitoring points shall be specified
and approved by EPA and MDHES during remedial design, considering appropriate points of
compliance.
Because the soils cleanup levels established in this Record of Decision are health based
standards for recreational use of the Site that do not provide for unlimited use with
unrestricted exposure, and because residual hazardous substances may be left on-site and
the cleanup is expected to take several years, the selected remedy will reguire five
year reviews under Section 121(c) of CERCLA, Section 300.430 (f) (4) (ii) of the NCP, and
applicable guidance to assure the long-term effectiveness of the remedy.
As there are residents and businesses utilizing groundwater for domestic and lawn
watering purposes in the immediate vicinity of the site, all wells within one-guarter
mile of contaminated site groundwater will be sampled on a routine basis for
contaminants. If site related contaminants are detected in any well above regulatory or
risk based levels, appropriate measures such as individual treatment at the tap shall be
implemented as deemed appropriate by the regulatory agencies.
Engineering and Institutional Controls
These controls are reguired to maintain the protectiveness of the remedy. Since cleanup
for all media are not likely to be met in less than 10 years, measures must be
instituted to control risks during implementation of the remedy. Fencing and posting of
areas where active remediation is occurring will be reguired to prevent unauthorized
access to contaminated media or to remedial action areas. The remedy itself includes
certain actions to contain and prevent migration of the contaminant plume during
implementation of the remedy. The design of this engineered containment will have to
consider and accommodate removal actions to be conducted at the Lower Area One Operable
Unit of the Silver Bow Creek/Butte Area NPL Site, particularly compensating for any
dewatering in connection with the removal of mine tailings at that site.
The institutional controls which must be implemented for the selected remedy include
adeguate zoning restrictions, conservation easements, and other controls to prevent any
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future residential use of the site and appropriate controls to prevent any water well
drilling in the contaminated groundwater plume and adjacent areas to prevent additional
receptors of contaminated groundwater or an expansion of the plume. As noted above, the
PRP's for the site have indicated that they are currently pursuing implementation of
these controls, in coordination with the city/county government. If controls deemed
adeguate by the agencies are not ultimately implemented, the assumptions used in
determining the points of compliance and other aspects of the selected remedy will be
invalid, and the contingency measures specified below will be implemented.
Contingency Measures
Soil Remediation
Soil cleanup levels have been determined based on the anticipated implementation of
zoning restrictions, conservation easements and groundwater restrictions by the PRPs and
Butte-Silver Bow County which will permanently prohibit residential and groundwater use
at the site. If these permanent site-wide changes are not implemented, revised soil
cleanup levels based on residential land use will be substituted for the recreational
land-use cleanup levels presented in this Record of Decision.
If the residence which currently exists on-site remains after implementation of the
institutional controls, contaminated soils subject to residential use will be removed
and replaced with clean soils. Soil removal levels will correspond to a 1 in 1,000,000
cancer risk level for residential land use for each contaminant of concern for the most
susceptible exposure pathway.
Groundwater Remediation
Groundwater remediation points of compliance are based on the expected implementation of
zoning restrictions, conservation easements, and groundwater restrictions by the PRPs
and Butte-Silver Bow County. If these permanent changes are not implemented, the
groundwater points of compliance will be revised to reguire compliance with remediation
levels throughout the contaminated groundwater plume.
Oils and Sludges Remediation
The selected remedy for oils and sludges is off-site incineration. Investigation during
the feasibility study determined that some licensed incinerators are reluctant to accept
wastes containing dioxin. If, subseguent to the implementation of the selected remedy,
no facility is available or willing to accept the site oils and sludges for
incineration, the lead agency will reguire the implementation of a contingency plan.
Such a contingency plan would consist of:
XCIII. A determination by the agencies that no facility is available or willing to
accept these wastes for treatment and that no facility is likely to become
available in the future;
XCIV. All practical methods for off-site treatment, disposal, reuse and recycling will
be investigated, and, if an appropriate option of this type is available, this
option will be substituted for the selected remedy; otherwise,
XCV. Oils and sludges will be treated using on-site incineration which will comply
with all ARARs.
The decisions to invoke any or all of these contingency measures may be made by the
agencies at any time during implementation of the remedial action, as appropriate.
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X. STATUTORY DETERMINATIONS
While the majority of the comments received from the community supported selection of
Alternative 5B, many of the comments submitted, particularly those submitted by the
PRPs, suggested use of a containment remedy rather than removal of the source of
contamination. However, after considering those comments fully, as evidenced in the
Responsiveness Summary, the agencies have determined that maximum removal of the source,
as outlined in the remedy description, is the appropriate remedy for the site and most
fully satisfies the selection criteria established in CERCLA and the NCP.
A number of site specific conditions have been considered by the agencies in the
determination of the remedy. Much of the contamination at the site exists in the form
of a light non-agueous phase liguid (LNAPL) which floating on the groundwater surface at
a depth that ranges from approximately 5 to 20 feet below ground surface. No dense
non-agueous phase liguid (DNAPL) was found at the site. Since the LNAPL material is
lighter than water, the groundwater essentially forms a floor which stops the downward
migration of the LNAPL. This material floating on top of the groundwater then
constitutes a major source of contamination to the groundwater and Silver Bow Creek by
dissolving into the groundwater. This dissolved phase of contamination then migrates
with the natural groundwater movement and spreads to surrounding areas and enters the
stream.
With a substantial amount of high-strength source material in contact with site
groundwater, a containment remedy may have to operate essentially forever in order to
prevent releases of contaminants to the stream and surrounding areas. Certain elements
of the selected remedy are intended to eliminate this continuing source of
contamination. After elimination of this source material, residual contamination levels
will be further reduced using long-term in-situ biological degradation. This may
ultimately allow a stabilization of site conditions such that containment at the site
may no longer be necessary.
Both DHES and EPA have determined that, considering all appropriate factors, including
site specific conditions and the remedy selection criteria specified in CERCLA and the
NCP, the remedy presented in this record of decision, including excavation and/or
treatment of the contaminated source material, both soils and LNAPL, is the appropriate
remedy for the site.
Under CERCLA section 121, MDHES and EPA must select a remedy that is protective of human
health and the environment, complies with applicable or relevant and appropriate
reguirements (unless a statutory waiver is justified), is cost-effective, and utilizes
permanent solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable. In addition, CERCLA includes a
preference for remedies that include treatment which permanently and significantly
reduces the volume, toxicity, or mobility of hazardous wastes as a principal element.
The following sections discuss how the selected remedy meets these statutory
reguirements.
Protection of Human Health and the Environment
The selected remedy protects human health and the environment first through containment
and then treatment of contaminants at the site, including a combination of soil and
groundwater remedial actions and use of institutional controls. Soil actions include
excavation and biological treatment of the LNAPL plume and contaminated soils. Treated
soils will be backfilled into excavated areas and revegetated.
Soil flushing and in situ biological treatment will be used in those areas where
excavation is not practicable or cost effective, as defined in the remedy description
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section. Implementation of the soil flushing alternative under 1-15/90 will eliminate
the need for relocation/excavation of the Interstate Highway and will reduce the levels
of contamination in those areas to the extent practicable. The other soils treatment
alternatives evaluated were not implementable for the contaminated soils under 1-15/90
without removing the roadbed. Prior to backfilling of excavated areas, in place
biological treatment of contaminated soils below the depth of excavation will reduce the
volume and toxicity of these materials and aid in groundwater control.
Biological treatment of the contaminated soil will reduce the threat of exposure through
direct contact with or ingestion of contaminated soil. By excavating the contaminated
soils and treating them, the cancer risks from exposure will be reduced to approximately
3.9 x 10[-6] for recreational use which is within the EPA's acceptable risk range of 1 x
10 [-4] to 1 x 10[-6] as specified by the NCP. In addition, the cleanup levels
established will be protective for industrial use at the site at an excess cancer risk
of approximately 2 x 10 [5] . It is anticipated that residential use at the site will be
prohibited through the use of institutional controls. There are no short term threats
associated with the selected remedy that cannot be readily controlled. In addition, no
adverse cross-media impacts are expected from the remedy.
Initially, containment of contaminated groundwater will reduce the potential for
exposure to contaminants in adjacent aguifers and in Silver Bow Creek. Permanent
protectiveness will be attained through removal and treatment of contaminant source
areas and then treatment of the groundwater, with treatment and discharge or reinjection
of extracted groundwater and in situ biological treatment of groundwater.
By first containing releases to surface water and then removing sources and remediating
the groundwater migrating to Silver Bow Creek, protection of affected surface waters
will be achieved. Also by treating extracted groundwater to drinking water standards
before discharging to surface water, the loading of contaminants of concern from this
site will be brought to within acceptable levels for Silver Bow Creek. Once all these
sources of contamination from the site are addressed, natural attenuation and
biodegradation will restore the stream to acceptable and protective levels for
contaminants of concern from this site. There are no short term threats associated with
the selected remedy that cannot be readily controlled. In addition, no adverse cross
media impacts are expected from the remedy.
A variety of engineering and institutional controls will be implemented with the remedy
to ensure protectiveness while the remedy is being implemented and in the future. As
there are residents and businesses utilizing groundwater for domestic and lawn watering
purposes in the immediate vicinity of the site, all wells within one-guarter mile of
contaminated site groundwater will be sampled on a routine basis for contaminants. If
site related contaminants are detected in any well above regulatory or risk based
levels, appropriate measures such as individual treatment at the tap shall be
implemented as deemed appropriate by the regulatory agencies. Institutional controls
will be implemented to prohibit groundwater use in the affected area and to prevent an
expansion of the plume. Fencing and posting to prevent unauthorized access to
contaminated media during remediation will be used.
Compliance with Applicable or Relevant and Appropriate Requirements
The final determination of ARARs by MDHES and EPA is set forth in Appendix A attached to
this Record of Decision. The selected remedy will comply with all applicable or
relevant and appropriate reguirements (ARARs). No waiver of ARARs is expected to be
necessary. Some significant ARARs are listed below.
Contaminant-specific ARARs
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Contaminant-specific ARARs typically set levels or concentrations of chemicals that may
be allowed in or discharged to the environment. The primary contaminant-specific ARARs
for this remedy are the maximum contaminant levels (MCLs) and non-zero maximum
contaminant level goals (MCLGs) established under the Safe Drinking Water Act. The
selected remedy will remediate existing groundwater contamination to achieve these
relevant and appropriate MCLs and MCLGs at appropriate points of compliance.
In addition the remedy will attain the surface water guality standards for site
contaminants in Silver Bow Creek, as designated under Montana law. ARM 16.20.623
specifies the standards for the "I" classification, applicable to Silver Bow Creek, and
reguires eventual attainment of Ambient Water Quality Criteria (Gold Book levels).
Since no treatment standards have been set for the RCRA listed wastes on site (F032 and
F034 wastes) as of the date of this Record of Decision, RCRA Land Disposal Restrictions
will not apply to the remedy.
Location-specific ARARs
Location-specific ARARs establish reguirements or limitations based on the physical or
geographic setting of the Site or the existence of protected resources on the Site.
Portions of the site are within a 100-year floodplain. Design of the remedy will have
to ensure that no prohibited structures or other artificial obstructions are constructed
in the floodplain. Although treated soils will be backfilled into excavated areas
within the floodplain, the floodplain may not be used for storage or disposal of wastes.
Regulations concerning the protection of wetlands, including those relating to the Fish
and Wildlife Coordination Act and Executive Orders 11,988 and 11,990, will apply to the
implementation of this remedy. The protected resource which has the potential to be
adversely affected by the selected remedy is wetland areas directly associated with
Silver Bow Creek. These wetland areas are also within the Lower Area One Operable Unit
of the Butte- Silver Bow Creek NPL site and are being addressed under removal actions
taking place within LAO. Consultation with the U.S. Fish and Wildlife Service during the
design and implementation phase will be reguired to establish if any additional
mitigative measures, beyond those planned for LAO, will be necessary.
Similarly, the one protected historical resource near the site is a slag wall that is
actually located on the Lower Area One Operable Unit. Any necessary mitigation measures
or other protection for that slag wall are being determined in connection with
activities at LAO.
Action-specific ARARs
Action-specific ARARs generally provide guidelines for the manner in which specific
activities must be implemented. Thus, compliance with many action-specific reguirements
must be ensured through appropriate design of the remedy.
The remedy will meet all action-specific ARARs, including the following RCRA
reguirements: monitoring for releases from waste management units, reguirements for
management of waste piles and land treatment units, and transportation reguirements, as
well as all reguirements for reclamation of excavated areas.
In addition, the remedy, as designed, will meet other action specific standards,
including Clean Air Act regulations for particulate matter, dust control practices that
achieve ambient air guality standards, Clean Water Act regulations reguiring run-on and
run-off controls that prevent any discharge of contaminants from remedial actions that
would violate surface water standards, sufficient treatment before reinjection of
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groundwater to ensure compliance with groundwater nondegradation standards, the
reguirements of the Underground Injection Control program under the Safe Drinking Water
Act and RCRA regulations associated with the treatment, storage and transportation of
hazardous waste.
Cost-Effectiveness
MDHES and EPA have determined that the selected remedy is cost effective in mitigating
the principal risks posed by the soils, sediments and contaminated groundwater. Section
300.430(f)(ii)(D) of the NCP reguires evaluation of cost-effectiveness. The remedy must
provide overall effectiveness proportional to its costs. Overall effectiveness is
determined by the following three balancing criteria: long-term effectiveness and
permanence; reduction of toxicity, mobility or volume through treatment; and short-term
effectiveness. The selected remedy rates very high in satisfying the first two criteria
and presents no substantial problems for short-term effectiveness. To the extent that
the estimated cost of the selected remedy exceeds the costs of other alternatives, the
difference in cost is reasonably related to greater overall effectiveness of the
selected remedy. The cost for the selected remedy was estimated by ARCO to be between
$27,530,000 to $55,200,000. MDHES and EPA have determined that this cost will be
reduced to at least between $26.9 million to $54.7 million and believe that the actual
cost will be near the bottom end of the range.
By comparison, the cost of the containment alternative supported by some of the PRPs in
their comments was estimated in the feasibility study at between $21.1 million and $36.6
million, and the agencies believe that, fairly assessing the present value of the costs
of perpetual operation of that system, the actual costs should be viewed as at the high
end of that range.
Based on data provided by ARCO in the feasibility study report, the selected remedy for
the soils (biological land treatment) provides the best overall effectiveness of all
alternatives considered proportional to its cost. The selected remedy will reduce the
toxicity, mobility, and volume of contaminated soils to the maximum extent practicable.
Also the implementation of this remedy will result in long-term effectiveness by
reducing residual carcinogenic risks to within the acceptable risk range through
permanent treatment.
Soil flushing and in situ bioremediation of areas beneath Interstate 1-15/90 was thought
to be a more cost effective remediation of this limited area of contamination than
demolition and excavation of the Interstate.
The selected remedy for groundwater provides the best overall effectiveness of all
alternatives considered proportional to its cost. The combination of plume containment
via hydraulic (pump and treat) and physical barriers and In Situ biological treatment,
will reduce the toxicity, mobility or volume of affected groundwater and will be a
permanent solution. This groundwater remediation approach, in combination with the
source removal accomplished by the soil remediation, is believed necessary in order to
adeguately protect Silver Bow Creek and the alluvial aguifers, in addition to providing
a realistic opportunity to fully stabilize and achieve cleanup goals at the site in the
future.
The selected remedy assures a high degree of certainty that the remedy will be effective
in the long-term because of the significant reduction of the toxicity and mobility of
the wastes achieved through biological treatment of the soil. The groundwater component
of the remedy ensures a high degree of certainty of effectiveness because the technology
employed is known to be effective for organic contaminated waste waters and will enhance
the degradation of contaminants remaining in situ.
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Utilization of Permanent Solutions and Alternative Treatment Technologies (or Resource
Recovery Technologies) to the Maximum Extent Practicable
MDHES and EPA have determined that the selected remedy represents the maximum extent to
which permanent solutions and treatment technologies can be utilized in a cost-effective
manner at the Site. Of those alternatives that are protective of human health and the
environment and comply with ARARs, MDHES and EPA have determined that this selected
remedy provides the best balance of trade-offs in terms of long-term effectiveness and
permanence, reduction in toxicity, mobility, or volume achieved through treatment,
short-term effectiveness, implementability and cost, while also considering the
statutory preference for treatment as a principal element and considering state and
community acceptance. The detailed evaluation of the balance of these criteria among
the alternatives considered is set forth in the FS Report and is summarized in section
VII, Description of Alternatives, of this record of decision. The selected remedy
includes treatment of contaminated media which will permanently and significantly reduce
the principal threats posed by the soils and groundwater. The other alternative
considered which could achieve similar or more substantial reductions, incineration, was
significantly more expensive. Other alternatives considered, including containment,
capping and partial excavation, did not offer similar prospects for effectiveness or
permanence.
Preference for Treatment as a Principal Element
By biologically treating the contaminated groundwater and the contaminated soils, the
selected remedy addresses the principal threats posed by the Site through the use of
treatment technologies. By utilizing treatment as a significant portion of the remedy,
the statutory preference for remedies that employ treatment as a principal element is
satisfied.
XI. DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for the Site was released for public comment May 5, 1993. The plan
identified Alternative 5B as the preferred remedy for the site. MDHES and EPA have
reviewed all written and oral comments submitted during the public comment period.
After consideration of the public comments, MDHES and EPA have determined that changes
to the Proposed Plan are warranted.
Comments received from ARCO and Butte-Silver Bow government indicate that further
restrictions on land and groundwater use at the site are likely. Based on these
anticipated changes, the agencies have modified the preferred remedy as follows:
XCVI. Soil cleanup levels have been modified anticipating that residential land use at
the site will be effectively prohibited. As such, revised soil cleanup levels
have been determined which will be protective for the anticipated industrial and
recreational uses. Revised soil cleanup levels are based on a 1 in 1,000,000
cancer risk level for recreational land use at the site for each contaminant of
concern for the most susceptible exposure pathway. Soil cleanup levels are fully
explained in Section IX - Cleanup Levels.
XCVII. Groundwater points of compliance have been modified anticipating that
access and use of site contaminated groundwater will be effectively
prohibited. Points of compliance have been set at the waste management
area boundary as explained in Section IX Points of Compliance. These
reguirements will be protective of surrounding groundwater and Silver Bow
Creek, and are fully consistent with the NCP and CERCLA reguirements.
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XCVIII. Recognizing the concerns expressed in the PRP comments about the
implementability of excavation below the groundwater table, excavation will
be to the extent practicable, as determined by the agencies. Contaminated
soils which remain will be addressed by in-site bioremediation.
XCIX. Soil washing was retained in the Proposed Plan as an optional soil treatment
technology. However, upon review of additional treatability studies conducted by
EPA at the site on soil washing, the agencies have determined that soil washing
does not provide significant advantages over biological treatment, either in cost
or effectiveness, to warrant retaining the technology further.
XII. REFERENCE S
Atlantic Richfield Company (ARCO). 1993a. Final Remedial Investigation Report, Montana
Pole and Treating Plant NPL Site. Prepared by James M. Montgomery, Consulting
Engineers, Inc., February 1993.
. 1993b. Final Feasibility Study, Montana Pole and Treating Plant NPL Site.
Prepared by James M. Montgomery, Consulting Engineers, Inc.,March 1993.
Calgon Carbon Corporation, 1991. Accelerated Column Testing for Removal of
Pentachlorophenol (PCP) and Naphthalene from a Groundwater Stream. Prepared for
Keystone, September 1991.
CDM, 1993. Final Baseline Risk Assessment for the Montana Pole NPL Site. Denver,
Colorado.
EPA (U.S. Environmental Protection Agency). 1991. Risk Assessment Guidance for
Superfund. Volume I; Human Health Evaluation Manual, Supplemental Guidance "Standard
Default Exposure Factors." March.
. 1989a. Risk Assessment Guidance for Superfund, Human Health Evaluation Manual,
Volume I. Interim Final. OSWER Directive 9285.701A, Office of Solid Waste and
Emergency Response. Washington, D.C.
. 1989b. Interim Procedures for Estimating Risks Associated with Exposures to
Mixtures of Chlorinated Dibenzo-p-dioxins and Dibenzofurans (CDDs and CDFs) and 1989
Update. EPA/625/3-89/016. March.
. 1989c. Exposure Factors Handbook. Exposure Assessment Group, Office of Health
and Environmental Assessment. Washington, D.C. EPA-600-889-043. May.
. 1989d. Interim Final Guidance for Soil Ingestion Rates. Office of Solid Waste
and Hazardous Waste. OSWER Directive 985.04.
. 1989e. Guidance on Preparing Superfund Decision Documents, Office of Emergency
and Remedial Response, Interim Final, EPA/540/G, July 1989.
Freeman, Harry M., 1989. Standard Handbook of Hazardous Waste Treatment and Disposal,
McGraw Hill, New York, N.Y.
Keystone, 1991a. Supplemental Work Plan for Additional Work Following the Fall
Sampling. Prepared for ARCO, April 1991.
Keystone, 1991b. Alternative Screening Document Montana Pole and Treating Plant Site,
Butte Montana. Prepared for ARCO, July 1991.
Woodward-Clyde, November 1988. Feasibility Study for Site Remediation, Libby, MT.
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TABLE 3
CONTAMINANTS OF CONCERN FOR HUMAN HEALTH
GROUNDWATER
SOIL
Arsenic
Chromium (VI)
Copper
Lead
Manganese
2-chlorophenol
4-chloro-3-methylphenol
2,4-dichlorophenol
2,4-dinitrophenol
2,4-dinitrotoluene
Dioxins/Furans
2-methyl-4,6-dinitrophenol
Acenaphthene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Fluorene
Indeno(1,2,3-cd)pyrene
2-methyl naphthalene
Naphthalene
Phenanthrene
Pyrene
Pentachlorophenol
2,3,5,6-tetrachlorophenol
2,4,6-trichlorophenol
Arsenic
4-chloro-3-methylphenol
Dioxins/Furans
2-methyl-4,6-dinitophenol
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Indeno(1,2,30cd)pyrene
Pentachlorophenol
2,4,6-trichlorophenol
SURFACE WATER
Arsenic
Copper
Lead
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Pyrene
Pentachlorophenol
Zinc
SEDIMENTS
Arsenic
Dioxins/Furans
Lead
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FIGURES
APPENDIX A
FINAL DETERMINATION AND DESCRIPTION OF
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
MONTANA POLE & TREATING PLANT NPL SITE
BUTTE, MONTANA
SEPTEMBER 1993
TABLE OF CONTENTS
1.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS)
1.1 ARARS FOR REMEDIAL ACTIONS
1.2 REQUIREMENTS FOR ARARS
1.3 ARARS APPLICABLE TO THE MONTANA POLE NPL SITE
2.0 FEDERAL ARARS
2.1 FEDERAL CONTAMINANT-SPECIFIC ARARS
2.1.1 Safe Drinking Water Act (Relevant and Appropriate)
2.1.2 Resource Conservation and Recovery Act (RCRA)
2.1.2.1 Groundwater Protection Standards (Applicable)
2.1.2.2 Hazardous Waste Management (Relevant and Appropriate)
2.1.2.3 Land Disposal Restrictions
2.1.3 Clean Air Act (Applicable)
2.1.3.1 Particulate Matter
2.1.3.2 Lead
2.1.3.3 Asbestos
2.1.4 Federal Insecticide, Fungicide, and Rodenticide Act (Applicable)
2.2 FEDERAL LOCATION-SPECIFIC ARARS
2.2.1 Fish and Wildlife Coordination Act (Applicable)
2.2.2 Floodplain Management Order (Applicable)
2.2.3 Protection of Wetlands Order (Applicable)
2.2.4 Resource Conservation and Recovery Act (Applicable and Relevant and
Appropriate)
2.2.5 Endangered Species Act (Applicable)
2.2.6 National Historic Preservation Act (Applicable)
2.2.7 Archaeological and Historic Preservation Act (Applicable)
2.2.8 Historic Sites, Buildings and Antiguities Act (Applicable)
2.2.9 Migratory Bird Treaty Act of 1918, as amended (Applicable)
2.2.10 Bald Eagle Protection Act of 1940, as amended (Applicable)
2.3 FEDERAL ACTION-SPECIFIG ARARS
2.3.1 Safe Drinking Water Act (Applicable)
2.3.2 Resource Conservation and Recovery Act (Applicable/Relevant and
Appropriate)
2.3.2.1 Criteria for Classification of Solid Waste Disposal Facilities Practices
(Applicable)
2.3.2.2 Standards Applicable to Transporters of Hazardous Waste (Applicable)
2.3.2.3 Standards for Owners and Operators of Hazardous Waste Treatment, Storage,
and Disposal Facilities (Applicable)
2.3.3 Hazardous Materials Transportation Act (Applicable) 2.4 FEDERAL STANDARDS
TO BE CONSIDERED
2.4.1 Federal Guidance Documents
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3 . 0 STATE OF MONTANA ARARS
3.1 MONTANA CONTAMINANT-SPECIFIC ARARS
3.1.1 Water Quality
3.1.1.1 Surface Water Quality Standards (Applicable)
3.1.1.2 Montana Groundwater Pollution Control System (Applicable)
3.2 MONTANA LOCATION-SPECIFIC ARARS
3.2.1 Floodplain and Floodway Management
3.2.1.1 Floodplain and Floodway Management Act (Applicable or Relevant and
Appropriate)
3.2.1.2 Floodplain Management Regulations (Applicable or Relevant and Appropriate)
3.2.1.3 Solid Waste Management Regulations (Applicable)
3.2.2 Natural Streambed and Land Preservation Standards (Applicable)
3.3 MONTANA ACTION-SPECIFIG ARARS
3.3.1. Water Quality
3.3.1.1 Groundwater Act (Applicable)
3.3.1.2 Public Water Supply Regulations (Applicable)
3.3.2 Air Quality
3.3.2.1 Air Quality Regulations (Applicable)
3.3.2.2 Reclamation and Revegetation Reguirements (Relevant and Appropriate)
3.4 OTHER LAWS
3.4.1 Groundwater Act
3.4.2 Water Rights
3.4.3 Occupational Health Act
3.4.4 Federal Occupational Health and Safety Act
3.4.5 Montana Safety Act
3.4.6 Employee and Community Hazardous Chemical Information Act
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LIST OF ACRONYMS
ARAR Applicable or Relevant and Appropriate Requirements
ATSDR Agency of Toxic Substances and Disease Registry
BAT Best Available Technology Economically Achievable
BCT Best Conventional Pollutant Control Technology
BPCTCA Best Practicable Control Technology Currently Available
BPJ Best Professional Judgment
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
of 1980
DNRC Department of Natural Resources and Conservation (Montana)
DSL Department of State Lands (Montana)
EPA U.S. Environmental Protection Agency
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
HWM Hazardous Waste Management
LNAPL Light Non-agueous Phase Liquid
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
MDHES Montana Department of Health and Environmental Sciences
MGWPCS Montana Groundwater Pollution Control System
MPDES Montana Pollutant Discharge Elimination System
NCP National Contingency Plan
NESHAPS National Emissions Standards for Hazardous Air Pollutants
NPL National Priorities List
NPDES National Pollutant Discharge Elimination System
PAH Polynuclear Aromatic Hydrocarbon
PCP Pentachlorophenol
POHC Principal Organic Hazardous Constituents
POTW Publicly Owned Treatment Works
PSD Prevention of Significant Deterioration
RCRA Resource Conservation and Recovery Act
RI/FS Remedial Investigation/Feasibility Study
ROD Record of Decision
SHPO State Historic Preservation Officer (Montana)
SIP State Implementation Plan
TBC To Be Considered
TU Turbidity Unit
UIC Underground Injection Control
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1.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS)
1.1 ARARS FOR REMEDIAL ACTIONS
Section 121(d)(2) of CERCLA, 42 U.S.C. S 9621(d)(2), requires that cleanup actions
conducted under CERCLA achieve a level or standard of control which at least attains
"any standard, requirement, criteria or limitation under any Federal environmental law
... or any [more strinqent] promulqated standard, requirement, criteria or limitation
under a State environmental or facility sitinq law ... [which] is leqally applicable to
the hazardous substance concerned or is relevant and appropriate under the circumstances
of the release of such hazardous substance or pollutant, or contaminant ..." The
standards, requirements, criteria or limitations identified pursuant to this section are
commonly referred to as "applicable or relevant and appropriate requirements," or ARARs.
The remedy for the Montana Pole & Treatinq Plant NPL site must comply with or attain all
ARARs unless specific ARAR waivers are invoked. See CERCLA S 121(d)(4), 42 U.S.C. S
9621(d)(4), and the NCP, 40 CFR 300.430(f)(1)(ii)(C). ARARs must be observed both durinq
the conduct of on site clean up activities and at the conclusion of the cleanup
activity, unless specifically exempted. [1] l 40 CFR S 300.435(b) (2); Preamble
to the Proposed NCP, 53 Fed. Req. 51440 (December 21, 1988); Preamble to the Final NCP,
55 Fed. Req. 8755-8757 (March 8, 1990).
1.2 REQUIREMENTS FOR ARARS
ARARs may be either "applicable" requirements or "relevant and appropriate"
requirements. Compliance with both is equally mandatory under CERCLA.[2] 2
See CERCLA S 121(d)(2)(A), 42 U.S.C. S9621(d)(2)(A).
Applicable requirements are those standards, requirements, criteria or limitations
promulqated under federal environmental or state environmental or facility sitinq laws
that specifically address a hazardous substance, pollutant, contaminant, remedial
action, location, or other circumstance found at a CERCLA site.
Relevant and appropriate requirements are those standards, standards, requirements,
criteria or limitations promulqated under federal environmental or state environmental
or facility sitinq laws that, while not "applicable" to hazardous substances,
pollutants, contaminants, remedial actions, locations, or other circumstances at a
CERCLA site, address problems or situations sufficiently similar to those encountered at
the CERCLA site that their use is well suited to the particular site. Factors which may
be considered in makinq this determination, when the factors are pertinent, are
presented in 40 CFR S 300.400(q)(2). They include, amonq other considerations,
examination of: the purpose of the requirement and the purpose of the CERCLA action;
the medium and substances requlated by the requirement and the medium and substances at
the CERCLA site; the actions or activities requlated by the requirement and the remedial
action contemplated at the site; and the potential use of resources affected by the
requirement and the use or potential use of the affected resource at the CERCLA site.
ARARs are divided into contaminant-specific, location-specific and action-specific
requirements. Contaminant-specific requirements qovern the release to the environment
of materials possessinq certain chemical or physical characteristics or containinq
specific chemical compounds. Contaminant-specific ARARs qenerally set human or
environmental risk-based criteria and protocol which, when applied to site-specific
conditions, result in the establishment of numerical action values. These values
establish the acceptable amount or concentration of a chemical that may be found in, or
discharqed to, the ambient environment.
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Location-specific ARARs relate to the geographic or physical position of the site,
rather than to the nature of site contaminants. These ARARs place restrictions on the
concentration of hazardous substances or the conduct of cleanup activities due to their
location in the environment.
Action-specific ARARs are usually technology- or activity-based reguirements, or are
limitations on actions taken with respect to hazardous substances. A particular
remedial activity will trigger an action-specific ARAR. Unlike chemical-specific and
location-specific ARARs, action-specific ARARs do not, in themselves, determine the
remedial alternative. Rather, action specific ARARs indicate how the selected remedy
must be achieved.
Only the substantive portions of the reguirements are ARARs. [3] 3 40 CFR S
300.5 (Definitions of "Applicable reguirements" and "Relevant and appropriate
reguirements.") See also Preamble to the Final NCP, 55 Fed. Reg. 8756-8757 (March 8,
1990). Administrative reguirements are not ARARs and thus do not apply to
actions conducted entirely on-site. Administrative reguirements are those which involve
consultation, issuance of permits, documentation, reporting, record keeping, and
enforcement. The CERCLA program has its own set of administrative procedures which
assure proper implementation of CERCLA. The application of additional or conflicting
administrative reguirements could result in delay or confusion.[4] 4 Preamble
to the Final NCP, 55 Fed. Reg. 8756-8757 (March 8, 1990); Compliance with Other Laws
Manual, Vol. I, pp. 1-11 through 1-12. Provisions of statutes or regulations
which contain general goals that merely express legislative intent about desired
outcomes or conditions but are non-binding are not ARARs.[5] 5 Preamble to the
Final NCP, 55 Fed. Reg. 8746 (March 8, 1990).
Only those state standards that are identified in a timely manner and are more stringent
than federal reguirements may be applicable or relevant and appropriate. To be an ARAR,
a state standard must be "promulgated," which means that the standards are of general
applicability and are legally enforceable.[6] 6 40 C.F.R. S
300.400(g)(4).
Additional documents may be identified as To Be Considered (TBCs). The TBC category
consists of advisories, criteria, or guidance that were developed by EPA, other federal
agencies, or states that may be useful in developing CERCLA remedies. These may be
considered as appropriate in selecting and developing cleanup actions.[7] 7
40 C.F.R. S 300.400(g)(3); 40 C.F.R. S 300.415(1); Preamble to the Final NCP, 55 Fed.
Reg. 8744-8746 (March 8, 1990).
1.3 ARARS APPLICABLE TO THE MONTANA POLE NPL SITE
This document constitutes MDHES' and EPA's final determination and detailed description
of ARARs for remedial action at the Montana Pole NPL site. The descriptions which
follow include summaries of the legal reguirements which are provided to allow the user
a reasonable understanding of the reguirements without having to refer constantly back
to the statute or regulation itself. However, in the event of any inconsistency between
the law and the summary provided in this document, the applicable or relevant and
appropriate reguirement is ultimately the reguirement as set out in the law, rather than
any paraphrase of the law provided here.
The ARARs analysis is based on section 121(d) of CERCLA, 42 U.S.C. S 9621(d); "CERCLA
Compliance with Other Laws Manual, Volume I," OSWER Dir. 9234.1-01 (August 8, 1988);
"CERCLA Compliance with Other Laws Manual, Volume II," OSWER Dir. 9234.1-02 (August,
1989); the Compendium of CERCLA ARARs Fact Sheets and Directives, OSWER Dir. 9347.3-15
(October 1991); the Preamble to the Proposed National Contingency Plan, 53 Fed. Reg.
51394, et. seg. (December 21, 1988); the Preamble to the Final National Contingency
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Plan, 55 Fed. Reg. 86668813 (March 8, 1990); and the Final National Contingency Plan, 40
CFR Part 300 (55 Fed. Reg. 8813-8865, March 8, 1990) (hereinafter referred to as "the
NCP").
2.0 FEDERAL ARARS
Potential Federal applicable or relevant and appropriate reguirements for the Montana
Pole NPL site are discussed below.
2.1 FEDERAL CONTAMINANT-SPECIFIC ARARS
2.1.1 Safe Drinking Water Act (Relevant and Appropriate)
The National Primary and Secondary Drinking Water Standards (40 CFR Parts 141, 143),
better known as "maximum contaminant levels" (MCLs), are not applicable to remedial
activities at the site because the aguifer underlying the site is not a public water
supply. These standards may be applicable in the future should the EPA detect an
exceedance at a public water outlet.
These drinking water standards are, however, relevant and appropriate because there is
groundwater in the area which is a potential source of drinking water and because the
aguifer feeds Silver Bow Creek, which is a potential drinking water source. The
determination that the drinking water standards are relevant and appropriate at the site
is fully supported by EPA regulations and guidance. The Preamble to the National
Contingency Plan (NCP) clearly states the MCLs are relevant and appropriate for
groundwater that is a current or potential source of drinking water, 55 Fed. Reg. 8750
(March 8, 1990), and this determination is further supported by reguirements in the
RI/FS section of the NCP, 40 CFR S 300.430 (e) (2) (i) (B) . EPA's Guidance on Remedial
Action For Contaminated Groundwater at Superfund Sites states that "MCLs developed under
the Safe Drinking Water Act generally are ARARs for current or potential drinking water
sources". Certain institutional controls may be implemented by the agreement of
Butte/Silver Bow County government and some of the PRPs. If such controls are
implemented to prevent the use of groundwater at the site as a drinking water source,
the need to comply with MCLs throughout groundwater plumes at the site may be obviated.
Thus, if sufficient institutional controls are implemented to prevent the use of
groundwater at the site as a drinking water source, the point of compliance for the MCL
ARARs will be the boundary of the waste management unit at the site, as discussed in the
ROD.
The MCLs are relevant and appropriate standards for the remedial action to be conducted
at this site. In addition, the non-zero maximum contaminant level goals (MCLGs) are
relevant and appropriate (55 Fed. Reg. 8750-8752 (March 8, 1990)). The points of
compliance for these standards are described in the ROD. The time for compliance is as
soon as feasible, and consistent compliance is necessary for completion of remedial
action. Once achieved, standards must be maintained.
Organics:
Benzene N.A.[18] 0.005[19]
Dichlorobenzene (para) 0.075 [20] 0.075[21]
Dichlorobenzene(ortho) 0.6 0.6
Ethylbenzene 0.7 0.7
Monochlorobenzene 0.1 0.1
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Toluene 1. 1.
Xylenes (total) 10. 10.
Pentachlorophenol N.A.[22] 0.001[23]
Benzo(a)pyrene N.A. 0.0002 [24]
2,3,7,8-TCDD (Dioxin) N.A. 3. x 10[-8]
18 The MCLG for benzene is zero. See 40 CFR S 141.50.
19 40 CFR S 141.61; ARM 16.20.204 (3) (e) .
20 40 CFR S 141.50.
21 40 CFR S 141.61; ARM 16.20.204 (3) (f) .
22 40 CFR S 141.50(a).
23 40 CFR S 141.61.
24 MCLs for Benzo(a)pyrene and 2,3,7,8-TCDD (Dioxin) were finalized July 17, 1992, at 57
Fed. Reg. 31846. These standards become effective January 17, 1994. However, as
promulgated MCLs they are still relevant and appropriate standards. The MCLG for both of
these compounds is zero, and accordingly is not considered an appropriate standard.
MCLs also form the basis for certain discharge standards and instream standards for
surface water, when those standards are more stringent than water guality criteria or
state water quality standards. Where this is the case, those standards are identified
in Tables 26, Surface Water Cleanup Levels and Corresponding Risks, and 27, Discharge to
Surface Water Cleanup Levels and Corresponding Risks, of the ROD.
2.1.2 Resource Conservation and Recovery Act (RCRA)
2.1.2.1 Groundwater Protection Standards (Applicable)
Under 40 CFR Part 264, Subpart F[25], 25 The State of Montana implements an
authorized RCRA program which includes the groundwater protection standards of 40 CFR
Part 264, Subpart F, (1990) as incorporated by reference in ARM 16.44.702.
concentration limits are set for hazardous constituents in groundwater. These standards
are applicable to remedial actions at the site. The limits specified for groundwater
protection are the same as or less stringent than the MCLs or MCLGs identified above for
those substances.[26] 26 The maximum groundwater concentrations specified are
(1) for arsenic and lead: the same as the MCL, .05 mg/1; (2) for cadmium: the same as
the old MCL, .010 mg/1, but not as stringent as the new MCL or the MCLG, .005 mg/1. No
solid waste groundwater standard is specified for copper.
2.1.2.2 Hazardous Waste Management (Relevant and Appropriate)
The Resource Conservation and Recovery Act of 1980, 42 U.S.C. S 6901, et seq., and
accompanying regulations set forth the standards for hazardous waste. The EPA has
stated that the test for determining whether such standards are applicable to cleanups
at superfund sites is:
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RCRA Subtitle C requirements for the treatment, storage, or disposal of hazardous waste
will be applicable if a combination of the following requirements are met: a) the waste
is listed or characteristic waste under RCRA; and b) either (1) the waste was treated,
stored, or disposed of after the effective date of the RCRA requirements (November 8,
1980); or (2) the activity at the CERCLA site constitutes treatment, storage or disposal
as defined under RCRA. (42 U.S.C. S 6901, et seq.)
Because of the location of the Montana Pole site, and the historical mining activities
which took place in this area, contaminated soil materials being addressed at the site
may include material derived during the extraction and beneficiation processes. Wastes
from ore extraction and beneficiation are specifically excluded from Subtitle C under
the mining waste (Bevill) exclusion, (RCRA Section 3001(b)(3)(A)(ii)). Therefore, RCRA
is probably not applicable to mine waste found at the site. Process waste, which is not
excluded by the Bevill exclusion, may also be present at the site; no determination on
that issue is made in this ROD.
Despite this situation, the EPA has determined that certain RCRA standards, and their
state counterparts, are relevant and appropriate to potential remedial actions planned.
The EPA's determination is based on the current definition of "relevant and appropriate"
found in the most recent version of the NCP at 40 CFR S 300.5. For mining waste,
certain provisions of RCRA can be relevant and appropriate if they meet the definition
of "relevant and appropriate" found in the NCP; if the activities contemplated at the
Montana Pole site will result in discrete areas of mining waste which resemble
traditional RCRA management units; and if the mining wastes are located in areas where
exposure is likely to occur, are toxic, are close to groundwater, or are otherwise
distinguishable from EPA' s generic determination of low toxicity/high volume for
RCRA-excluded mining waste. See Preamble to Final NCP, 55 Fed. Reg. 8763-8764 (March 8,
1990); CERCLA Compliance With Other Laws Manual, Volume II (August 1989) (OSWER Dir. No.
9234.1-02) p.6-4; Preamble to Proposed NCP, 58 Fed. Reg. 51447 (Dec. 21, 1988); and
guidance entitled "Consideration of RCRA Requirements in Performing CERCLA Responses at
Mining Wastes Sites," August 19, 1986 (OSWER).
At Montana Pole, if mining wastes are controlled in place as discrete units, or are
actively collected and managed as discrete units, the following RCRA standards will be
ARARs:
40 CFR S 264.18(a) and (b), which impose siting restrictions and conditions on the
treatment, storage, or disposal of wastes;
certain provisions of 40 CFR Part 263, which govern the transportation of wastes;
40 CFR SS 264.116 and 264.119, regarding notification and filing
requirements;
40 CFR S 264.228(a)(2)(i), addressing dewatering of wastes;
40 CFR S 264.228(a)(2)(iii)(B),(C), and (D), and 40 CFR S264.251(c),(d), and (f),
regarding run-on and run-off controls; and
40 CFR SS 257.3-1(a), 257,3-2, 257.3-3, and 257.3-4, which impose general requirements
on waste handling, storage, and disposal.
Land disposal restrictions, discussed below with respect to organic substances at the
site, are not identified as relevant and appropriate for these mining wastes, in
accordance with current EPA guidance.
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2.1.2.3 Land Disposal Restrictions
In December 1990, EPA listed new hazardous wastes consisting of waste waters, process
residuals, preservative drippage, and spent formulations of wood preserving processes
generated at plants using chlorophenolic and creosote formulations for wood preserving
waste nos. F032 and F034. 55 Fed. Reg. 50,450; 50,482, to be codified at 40 CFR S
261.31(a). Because the site is a wood treating site that used pentachlorophenol and
creosote, these newly-listed wastes are found in various locations throughout the site.
Land disposal restrictions (LDRs) may be applicable to site soils contaminated with F032
and F034 waste if placement of those soils occurs.
LDRs typically set concentration levels or treatment standards that hazardous wastes
must meet before they can be land disposed. These treatment standards represent best
demonstrated available treatment technology (BOAT) for these wastes. In some cases,
however, hazardous wastes and appropriate treatment levels may differ significantly even
within the same class of hazardous waste. See 40 CFR S 268.44. Conseguently, a variance
from an LDR treatment standard may be appropriate when a waste "differs significantly
from waste analyzed in developing the treatment standard." 40 CFR SS 268.44 (a) and (h) .
The Corrective Action Management Units (CAMU) rule, see 58 Fed. Reg. 8658 (February 16,
1993), provides that remediation wastes from anywhere at a facility or from releases
outside of the facility can be placed into either a corrective action management unit or
a temporary unit without triggering land disposal restrictions and minimum technology
reguirements. Therefore, with regard to the placement of F032 and F034 wastes at the
site, the CAMU rule is applicable. Thus, wastes which are excavated can be placed in
treatment units in compliance with RCRA reguirements, even if the wastes are at levels
above land ban standards.
2.1.3 Clean Air Act (Applicable)
Section 109 of the Clean Air Act, 42 U.S.C. S 7409, and implementing regulations found
at 40 CFR Part 50 set national primary and secondary ambient air guality standards.[27]
27 The ambient air guality standards established as part of Montana's
approved State Implementation Plan in many cases provide more stringent or additional
standards. Moreover, the federal regulations apply the standards only to "major
sources;" the state regulations are fully applicable throughout the state and are not
limited to "major sources." See ARM 16.8.808 and 16.8.811 -821. As part of an
EPA-approved State Implementation Plan, the state standards are also federally
enforceable. Thus, the state standards are identified in this section together with the
federal standards. National primary ambient air guality standards define
levels of air guality which are necessary, with an adeguate margin of safety, to protect
the public health. National secondary ambient air guality standards define levels of
air guality which are necessary to protect the public welfare from any known or
anticipated adverse effects of a pollutant. The ambient air guality standards and other
standards set out below are applicable for releases into the air resulting from remedial
action.[28] 28 Ambient air guality standards are also provided for carbon
monoxide, hydrogen sulfide, nitrogen dioxide, sulfur dioxide, and ozone. If emissions
of these compounds were to occur at the site in connection with any remedial action,
these standards would also be applicable. See ARM 16.8.811 - 820. These
standards must be met both during the design and implementation phases of the remedial
action.
2.1.3.1 Particulate Matter
The ambient air guality standard for particulate matter of less than or egual to 10
micrometers in diameter (PM-10) is 150 micrograms per cubic meter, 24 hour average
concentration; 50 micrograms per cubic meter, annual arithmetic mean. 40 CFR S 50.6[29]
29 The state air guality regulations provide an eguivalent standard, see ARM
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16.8.821, which is enforceable in Montana as part of the State Implementation
Plan. (Applicable).
In addition, state law provides an ambient air quality standard for settled particulate
matter. Particulate matter concentrations in the ambient air shall not exceed the
following 30-day average: 10 grams per sguare meter. ARM 16.8.818 (Applicable).
The Butte area has been designated by EPA as non-attainment for total suspended
particulates. 40 CFR S 81.327. ARM 16.8.1401 (Applicable) requires that any new source
of airborne particulate matter that has the potential to emit less than 100 tons per
year of particulates shall apply best available control technology (BACT); any new
source of airborne particulate matter that has the potential to emit more than 100 tons
per year of particulates shall apply lowest achievable emission rate (LAER). The BACT
and LAER standards are defined in ARM 16.8.1401.
2.1.3.2 Lead
ARM S 16.8.815 (Applicable). Lead concentrations in the ambient air shall not exceed
the following 90-day average (annual arithmetic mean): 1.5 micrograms Pb per cubic
meter of air. 40 CFR S 50.12[30] 30 The state air quality regulations provide
an equivalent standard, see ARM 16.8.815, which is enforceable in Montana as part of the
State Implementation Plan. (Applicable).
2.1.3.3 Asbestos
The National Emission Standards for Hazardous Air Pollutants (40 CFR Part 61) designate
certain air pollutants that cause serious adverse health effects. Subpart M (SS
61.141-157) specifies control requirements for asbestos. 40 CFR SS 61.145 and 61.150
(Applicable) cover demolition and waste disposal for demolition operations and would be
applicable if asbestos is encountered during implementation of the remedy.
2.1.4 Federal Insecticide, Fungicide, and Rodenticide Act (Applicable)
This statute (7 U.S.C. S 136 et seq.) regulates the sale, distribution and use of all
pesticide products in the United States and is applicable to any alternative involving
the recycling and reuse of pentachlorophenol and other wood-treating pesticides. Under
FIFRA, use of a registered pesticide product in a manner inconsistent with its labeling
is a violation of the Act (7 U.S.C. S 136j) . Recovered pesticides may be reused provided
they meet new product labeling specifications, which include concentration limits for
pesticides in solution.
2.2 FEDERAL LOCATION-SPECIFIC ARARS
2.2.1 Fish and Wildlife Coordination Act (Applicable)
This standard (16 USC SS 1531-1566, 40 CFR S 6.302(g)) requires that federal agencies or
federally funded or authorized projects ensure that any modification of any stream or
other water body affected by any action authorized or funded by the federal agency
provide for adequate protection of fish and wildlife resources. Compliance with this
ARAR requires EPA and MDHES to consult with the U.S. Fish and Wildlife Service and the
Wildlife Resources Agency of the affected State. Further consultation will occur
during the remedial design process and specific mitigative measures may be identified in
consultation with the appropriate agencies.
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2.2.2 Floodplain Management Order (Applicable)
This requirement (40 CFR Part 6, Appendix A, Executive Order No. 11,988) mandates that
federally-funded or authorized actions within the 100 year floodplain avoid, to the
maximum extent possible, adverse impacts associated with development of a floodplain.
Compliance with this requirement is detailed in EPA's Auqust 6, 1985 "Policy on
Floodplains and Wetlands Assessments for CERCLA Actions." Specific measures to minimize
adverse impacts may be identified followinq consultation with the appropriate
aqencies.
If the remedial action is found to potentially affect the floodplain, the followinq
information will be produced: a Statement of Findinqs which will set forth the reasons
why the proposed action must be located in or affect the floodplain; a description of
siqnificant facts considered in makinq the decisions to locate in or affect the
floodplain or wetlands includinq alternative sites or actions; a statement indicatinq
whether the selected action conforms to applicable state or local floodplain protection
standards; a description of the steps to be taken to desiqn or modify the proposed
action to minimize potential harm to or within the floodplain; and a statement
indicatinq how the proposed action affects the natural or beneficial values of the
floodplain.
2.2.3 Protection of Wetlands Order (Applicable)
This requirement (40 CFR Part 6, Appendix A, Executive Order No. 11,990) mandates that
federal aqencies and PRPs avoid, to the extent possible, the adverse impacts associated
with the destruction or loss of wetlands and to avoid support of new construction in
wetlands if a practicable alternative exists. Section 404(b)(1), 33 U.S.C. S 1344(b)(1),
also prohibits the discharqe of dredqed or fill material into waters of the United
States. Toqether, these requirements create a "no net loss" of wetlands standard.
In order to comply with this ARAR, EPA and MDHES will consult with the U.S. Army Corps
of Enqineers (COE) or the U.S. Fish and Wildlife Service to determine whether wetlands
exist at the site and, if present, what cateqory of wetland they represent. Compliance
will be addressed by assessment of existinq wetlands at the site, followed by
replacement of any wetlands destroyed by the remedial action.
2.2.4 Resource Conservation and Recovery Act (Applicable and Relevant and
Appropriate)
The requirements set forth at 40 CFR S 264.18(a) and (b)[31] 31 These
requirements are applicable throuqh their incorporation by reference in Montana's
requlations for its authorized RCRA proqram. ARM 16.44.702. provide that (a)
any hazardous waste facility must not be located within 61 meters (200 feet) of a fault
(see Appendix VI of Part 264), and (b) any hazardous waste facility within the 100 year
floodplain must be desiqned, constructed, operated and maintained to avoid washout. Any
discrete disposal or storaqe facilities which remain on-site as part of remedial
activities must meet these standards.
2.2.5 Endangered Species Act (Applicable)
This statute and implementinq requlations (16 USC SS 1531-1543, 50 CFR S 402, 40 CFR
6.302(h)) require that any federal activity or federally authorized activity may not
jeopardize the continued existence of any threatened or endanqered species or destroy or
adversely modify a critical habitat.
Compliance with this requirement involves consultation between EPA and the U.S. Fish and
Wildlife Service, resultinq in a determination as to whether there are listed or
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proposed species or critical habitats present on the site, and, if so, whether any
proposed activities will impact such wildlife or habitat. At this time, the U.S. Fish
and Wildlife Service has not identified any threatened or endangered species or critical
habitat on the site. Therefore, no further activities are required by this ARAR.
2.2.6 National Historic Preservation Act (Applicable)
This statute and implementing regulations (16 U.S.C. S 470, 40 CFR S 6.310(b), 36 CFR
Part 800), require federal agencies or federal projects to take into account the effect
of any federally-assisted undertaking or licensing on any district, site, building,
structure or object that is included in, or eligible for, the Register of Historic
Places. To comply with this ARAR, EPA and MDHES may consult the State Historic
Preservation Officer (SHPO), who can assist in identifying cultural resources and
assessing whether proposed cleanup actions will impact the resources. If remedial
action is likely to have an adverse effect on any cultural resources which are on or
near the site, EPA and MDHES must examine whether feasible alternatives exist that would
avoid such effects. If effects cannot reasonably be avoided, measures should be
implemented to minimize or mitigate the potential effect.
NHPA regulations reserve formal determination of eligibility for the National Register
of Historic Places and "no adverse effects" determinations for Federal agencies. The
EPA is using the Cultural Resource Inventory for the Montana Pole and Treating Plant NPL
Site completed by ARCO and supplementing this with site-specific historical inventory
and adverse effects determinations. The EPA will continue to consult with the SHPO to
identify specific mitigative measures, if necessary.
Research into the Montana Pole and Treating Plant revealed that the facility began
operations in July 1946 and remained in business until May 17, 1984 (Camp, Dresser, &
McKee 1990) . Subsequent salvage and cleanup operations conducted by the EPA on the site
removed most of the plant's facilities. The area was surveyed for prehistoric cultural
remains but due to the disturbed condition of the site area, the potential for the
existence of such materials is minimal and none have been observed. In addition, the
plant is less than 50 years old and therefore it does not qualify as a historic site. No
further cultural resource inventory or evaluation has been conducted on the site.
In April 1992, ARCO, EPA, MDHES, the Advisory Council on Historic Preservation, the
State Historic Preservation Officer, and the local governments of Butte/Silver Bow,
Anaconda/Deer Lodge, and Walkerville entered into a Programmatic Agreement to ensure the
consideration of cultural and historic values in a systematic and comprehensive manner
throughout the Clark Fork Basin in connection with remedial action at the four Clark
Fork Superfund sites. This Programmatic Agreement may provide additional consideration
of the factors to be addressed under the National Historic Preservation Act, and the
other two cultural resources statutes that are ARARs, the Archaeological and Historic
Preservation Act and the Historic Sites, Buildings and Antiquities Act, discussed below.
2.2.7 Archaeological and Historic Preservation Act (Applicable)
This statute and implementing regulations (16 U.S.C. S 469, 40 CFR S 6.301(c)) establish
requirements for the evaluation and preservation of historical and archaeological data,
which may be destroyed through alteration of terrain as a result of federal construction
project or a federally licensed activity or program. This requires the EPA or the PRP
to survey the site for covered scientific, prehistorical or archaeological artifacts.
The results of this survey will be reflected and documented in the administrative
record. As noted above, that survey revealed no covered artifacts. Nevertheless,
preservation of appropriate data concerning the artifacts is hereby identified as an
ARAR requirement, to be completed during the implementation of this remedial action, if
any covered artifacts are discovered. 2.2.8 Historic Sites, Buildings and Antiquities
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Act (Applicable)
This requirement (16 U.S.C. S 461 et seq.; 40 CFR S 6.301 (a)) states that "[in
conductinq an environmental review of a proposed EPA action, the responsible official
shall consider the existence and location of natural landmarks usinq information
provided by the National Park Service pursuant to 36 CFR S 62.6(d) to avoid undesirable
impacts upon such landmarks." "National natural landmarks" are defined under 36 CFR S
62.2 as:
[Area(s) of national siqnificance located within [the U.S.] that contains(s) an
outstandinq representative example(s) of the nation's natural heritaqe, includinq
terrestrial communities, aquatic communities, landforms, qeoloqical features, habitats
of natural plant and animal species, or fossil evidence of development of life on earth.
Under the Historic Sites Act of 1935, the Secretary of the Interior is authorized to
desiqnate areas as National Natural Landmarks for listinq on the National Reqistry of
Natural Landmarks. To date no such landmarks are identified in the area. Therefore, no
further actions are necessary to comply with this requirement.
2.2.9 Migratory Bird Treaty Act of 1918, as amended (Applicable
This requirement (16 U.S.C. SS 703 et seq.) establishes a federal responsibility for the
protection of the international miqratory bird resource and requires continued
consultation with the U.S. Fish and Wildlife Service durinq remedial desiqn and remedial
construction to ensure that the cleanup of the site does not impact miqratory birds.
Specific mitiqative measures may be identified for compliance with this requirement.
2.2.10 Bald Eagle Protection Act of 1940, as amended (Applicable)
This requirement (16 U.S.C. SS 668 et seq.) establishes a federal responsibility for
protection of the bald and qolden eaqle and requires continued consultation with the
U.S. Fish and Wildlife Service durinq remedial desiqn and remedial construction to
ensure that the cleanup of the site does not adversely affect the bald and qolden eaqle.
To date, bald and qolden eaqles have not been identified at the site. Accordinqly, no
further actions are required for compliance with this requirement, unless bald or qolden
eaqles are identified.
2.3 FEDERAL ACTION-SPECIFIC ARARS
2.3.1 Safe Drinking Water Act (Applicable)
The underqround injection control (UIC) proqram requirements found at 40 CFR Part 144
would be applicable for alternatives that involve reinjection of pumped and treated
qroundwater. The proqram divides wells into five classes for permittinq purposes.
Class I wells are used to inject hazardous waste or fluids beneath the lower-most
formation containinq, within one-quarter mile, an underqround source of drinkinq water.
Class IV wells are used to dispose of hazardous waste into or above a formation which
contains, within one-quarter mile of the well, an underqround source of drinkinq water.
Class IV wells are qenerally prohibited, except for reinjection of treated qroundwater
into the same formation from which it was withdrawn, as part of a CERCLA cleanup or RCRA
corrective action. Class II and III wells deal with mininq and oil and qas production
and so are inapplicable to any remedial action at the site. Class V wells constitute
all other injection wells. There is no requlation of Class V wells.
The aquifer underlyinq the site is considered an underqround source of drinkinq water,
so any well injectinq above the aquifer would be a Class IV well. Generally, the
construction, operation, and maintenance of a Class IV well is prohibited by 40 CFR S
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144.13. However, wells used to inject contaminated ground water that has been treated
and is being reinjected into the same formation from which it was drawn are not
prohibited if such injection is approved by EPA pursuant to provisions for cleanup of
releases under CERCLA, or pursuant to reguirements and provisions under RCRA. 40 CFR
S 144.23 reguires that Class IV wells be plugged or otherwise closed in a manner
acceptable to the EPA Regional Administrator.
2.3.2 Resource Conservation and Recovery Act (Applicable/Relevant and
Appropriate)
2.3.2.1 Criteria for Classification of Solid Waste Disposal Facilities Practices
(Applicable)
The criteria contained in 40 CFR Part 257 set reguirements for management of solid waste
disposal. Part 257.3-1(a) states that facilities or practices in the floodplain shall
not result in the washout of solid waste so as to pose a hazard to human life, wildlife,
or land or water resources. Part 257.3-2 provides for the protection of threatened or
endangered species. Part 257.3-3 provides that a facility shall not cause the discharge
of pollutants into waters of the United States. Part 257.3-4 states that a facility or
practice shall not contaminate underground drinking water.
2.3.2.2 Standards Applicable to Transporters of Hazardous Waste (Applicable)
The regulations at 40 CFR Part 263 [32] 32 See also the substantially
eguivalent regulations at ARM 16.44.401-425 which are implemented as part of Montana's
authorized RCRA program. establish standards that apply to persons that
transport hazardous waste within the United States. If hazardous waste is transported on
a rail-line or public highway on-site, or if transportation occurs off-site, these
regulations will be applicable.
2.3.2.3 Standards for Owners and Operators of Hazardous Waste Treatment, Storage,
and Disposal Facilities (Applicable)
In considering hazardous waste regulations at the site, the nature of the hazardous
wastes involved may affect the RCRA regulations that apply to the particular wastes. As
discussed in the contaminant-specific ARARs above, the site includes F032 and F034
listed wastes, other wastes which may be characteristic hazardous waste under RCRA, and
certain wastes which are Bevill-excluded mining wastes for which certain RCRA
regulations are prescribed as relevant and appropriate. In addition, the site includes
wastes which are most appropriately characterized as K001 wastes, listed in 40 CFR S
261.32 as "bottom sediment sludge from the treatment of waste waters from wood
preserving processes that use creosote and/or pentachlorophenol." A water treatment
plant is currently operating on site and is separating the wastes which would fall
within the K001 listing from water before that water is discharged to Silver Bow Creek.
These wastes are collected in carbon filters which are used for the treatment process.
Accordingly, the spent carbon containing these wastes should be classified as K001
listed waste.
A. Releases from Solid Waste Management Units
The regulations at 40 CFR 264, Subpart F,[33] 33 These regulations are
incorporated by reference and are implemented by DHES as part of Montana's authorized
RCRA program. See ARM 16.44.702. establish reguirements for groundwater
protection for RCRA-regulated solid waste management units (i.e., waste piles, surface
impoundments, land treatment units, and landfills). Subpart F provides for three general
types of groundwater monitoring: detection monitoring (40 CFR S 264.98); compliance
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monitoring (40 CFR S 264.99); and corrective action monitoring (40 CFR S 264.100).
Monitoring wells must be cased according to S 264.97(c).
Monitoring is reguired during the active life of a hazardous waste management unit. At
closure, if all hazardous waste, waste residue, and contaminated subsoil is removed, no
monitoring is reguired. If hazardous waste remains, the monitoring reguirements
continue during the 40 CFR S264.117 closure period.
B. Closure and Post-Closure
40 CFR Part 264, Subpart G,[34] 34 These regulations are incorporated by
reference and are implemented by DHES as part of Montana's authorized RCRA program. See
ARM 16.44.702. establishes that hazardous waste management facilities must be
closed in such a manner as to (a) minimize the need for further maintenance and (b)
control, minimize or eliminate, to the extent necessary to protect public health and the
environment, post-closure escape of hazardous wastes, hazardous constituents, leachate,
contaminated runoff or hazardous waste decomposition products to the ground or surface
waters or to the atmosphere.
Closure includes appropriate caps for the waste management unit. Facilities reguiring
post-closure care must undertake appropriate monitoring and maintenance actions, control
public access, and control postclosure use of the property to ensure that the integrity
of the final cover, liner, or containment system is not disturbed. 40 CFR S 264.117.
In addition, all contaminated eguipment, structures and soil must be properly disposed
of or decontaminated unless exempt. 40 CFR S 264.114. A survey plat should be
submitted to the local zoning authority and to the EPA Regional Administrator indicating
the location and dimensions of landfill cells or other hazardous waste disposal units
with respect to permanently surveyed benchmarks. 40 CFR S 264.116. 40 CFR S 264.228(a)
reguires that at closure, free liguids must be removed or solidified, the wastes
stabilized, and the waste management unit covered. If permanent waste management units
are reguired because biodegradation treatment does not achieve risk based cleanup
reguirements, these reguirements will be applicable to above ground units containing the
waste.
C. Waste Piles (Applicable)
40 CFR Part 264, Subpart L,[35] 35 These regulations are incorporated by
reference and are implemented by DHES as part of Montana's authorized RCRA program. See
ARM 16.44.702. establishes a framework for the safe operation of a waste pile
until permanent disposal occurs. The framework includes a run-on control system, and a
run-off control system and collection and holding systems to prevent the further release
of contaminants from the waste pile. These reguirements are applicable to areas where
contaminated soils or materials are temporarily stored or placed prior to treatment or
other disposal.
D. Land Treatment (Applicable)
The reguirements of 40 CFR Part 264, Subpart M,[36] 36 These regulations are
incorporated by reference and are implemented by DHES as part of Montana's authorized
RCRA program. See ARM 16.44.702. regulate the management of "land treatment
units"[37] 37 Land treatment occurs when hazardous waste is applied onto or
incorporated into the soil surface. that treat or dispose of hazardous waste;
these reguirements are applicable for any land treatment units established at the site.
The owner or operator of a land treatment unit must design treatment so that hazardous
constituents placed in the treatment zone are degraded, transformed, or immobilized
within the treatment zone. "Hazardous constituents" are those identified in Appendix
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VIII of 40 CFR Part 261 that are reasonably expected to be in, or derived from, waste
placed in or on the treatment zone. Design measures and operating practices must be set
up to maximize the success of degradation, transformation, and immobilization
processes. The treatment zone is the portion of the unsaturated zone below and
including the land surface in which the owner or operator intends to maintain the
conditions necessary for effective degradation, transformation, or immobilization of
hazardous constituents. The maximum depth of the treatment zone must be no more than
1.5 meters (five feet) from the initial soil surface; and more than one meter (three
feet) above the seasonal high water table.
Subpart M also reguires the construction and maintenance of control features that
prevent the run-off of hazardous constituents and the run-on of water to the treatment
unit. The unit must also be inspected weekly and after storms for deterioration,
malfunctions, improper operation of run-on and runoff control systems, and improper
functioning of wind dispersal control measures.
An unsaturated zone monitoring program must be established to monitor soil and soil-pore
liguid to determine whether hazardous constituents migrate out of the treatment zone.
Specifications related to the monitoring program are contained in section 264.278.
E. Landfills (Applicable)
40 CFR Part 264, Subpart N,[38] 38 These regulations are incorporated by
reference and are implemented by DHES as part of Montana's authorized RCRA program. See
ARM 16.44.702. applies to entities that dispose of hazardous waste in
landfills.[39] 39 These regulations are incorporated by reference and are
implemented by DHES as part of the Montana's authorized RCRA program. See ARM
16.44.702. The regulations specify appropriate liner systems and leachate
collection systems for landfills, run-on and run-off management systems, and wind
dispersal controls for landfills. These regulations set forth specific reguirements for
landfill monitoring and inspection, surveying and record keeping, and closure and
postclosure care. If permanent waste management units are reguired because
biodegradation treatment does not achieve risk based cleanup reguirements, these
reguirements will be applicable to above ground units containing the waste. F.
Incineration (Applicable)
The regulations at 40 CFR SS 264.340 - 351 and 40 CFR Part 265, Subpart 0,[40]
40 These regulations are incorporated by reference and are implemented by DHES
as part of Montana's authorized RCRA program. See ARM 16.44.702 and 16.44.609 (Interim
status). will be ARARs for any alternative involving on-site incineration of
hazardous waste. Since permits are not reguired for on-site incineration, only the
substantive standards of the Part 264 permit reguirements would be applicable. The
standards reguire an owner or operator of a hazardous waste incinerator to conduct a
waste analysis in conjunction with obtaining a treatment, disposal, and storage permit
for the incinerator. A permit designates one or more Principal Organic Hazardous
Constituents (POHCs) from those constituents listed in 40 CFR Part 261. Appendix VIII.
A POHC designation is based on the degree of difficulty of incineration of the organic
constituents in the waste feed from trial burns. Organic constituents that represent the
greatest degree of difficulty are most likely to be designated a POHC. Incineration of
POHCs designated in the permit must achieve a 99.99% destruction and removal efficiency.
Incineration of dioxins must achieve a destruction and removal efficiency of 99.9999%.
40 CFR 264.343(a).
An incinerator burning hazardous waste and producing stack emissions of more than 1.8
kilograms per hour (4 pounds per hour) of hydrogen chloride (Hcl) must control HC1
emissions such that the rate of emission is no greater than the larger of either 1.8
kilograms per hour of 1% of the Hcl in the stack gas prior to entering any pollution
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control equipment. 40 CFR S 264.343 (b) . A permitted incinerator must not emit
particulate matter in excess of 180 milligrams per dry standard cubic meter (40 CFR S
264.343(c)). The owner or operator must monitor combustion temperature, waste feed
rate, CO emissions, and combustion gas velocity. The incinerator must be visually
inspected daily, and the emergency waste feed cutoff system and associated alarms must
be tested weekly. At closure, all hazardous waste residues must be removed from the
incinerator site.
2.3.3 Hazardous Materials Transportation Act (Applicable)
The Hazardous Materials Transportation Act (49 USC SS 1801-1813), as implemented by the
Hazardous Materials Transportation Regulations (49 CFR Parts 10, 171-177) , regulates the
transportation of hazardous materials. The regulations apply to any alternatives
involving the transport of hazardous waste offsite, on public highways on-site, or by
rail line.
2.4 FEDERAL STANDARDS TO BE CONSIDERED (TBC's)
2.4.1 Federal Guidance Documents
Many of the procedures and standards to be used in a CERCLA action are set forth in
guidance documents issued by EPA. A list of the types of guidance that are TBC is
included in the preamble to the Final NCP, 55 Fed. Reg. 8765 (March 8, 1990). That
guidance, along with current updates of and additions to that guidance, is to be
considered in conducting the RI/FS and selecting and implementing the remedy at the
site.
3 . 0 STATE OF MONTANA ARARS
3.1 MONTANA CONTAMINANT-SPECIFIC ARARS
3.1.1 Water Quality
3.1.1.1 Surface Water Quality Standards (Applicable)
Under the state Water Quality Act, 75-5-101 et seg., MCA, the state has promulgated
regulations to preserve and protect the guality of surface waters in the state. These
regulations classify state waters according to guality, place restrictions on the
discharge of pollutants to state waters and prohibit the degradation of state waters.
The requirements listed below would be applicable to any discharge to surface waters in
connection with the remedial action.
ARM 16.20.604 (1) (b) [41] 41 Unless otherwise specified, all regulatory
citations are to the Administrative Rules of Montana. (Applicable) provides
that Silver Bow Creek (mainstem) from the confluence of Blacktail Deer Creek to Warm
Springs Creek is classified "I" for water use.
The "I" classification standards are contained in ARM 16.20.623 (Applicable) of the
Montana water quality regulations. This section states:
The goal of the state of Montana is to have these waters fully support the following
uses: drinking, culinary, and food processing purposes after conventional treatment;
bathing, swimming, and recreation; growth and propagation of fishes and associated
aquatic life, waterfowl, and furbearers; and agricultural and industrial water supply.
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In order to achieve this goal the I classification standards limit discharges of toxic
or deleterious substances from new point sources to the larger of either Gold Book
levels[42] 42 ARM 16.20.603(10) defines Gold Book levels as "the freshwater
acute or chronic levels or the levels for water and fish ingestion that are listed in
Update Number Two (5/1/87) of Quality Criteria for Water 1986 (EPA
440/5-86-001). or one- half of the mean instream concentrations immediately
upstream of the discharge point.[43] 43 Mean instream concentration is the
monthly instream concentration, as defined by the MDHES Water Quality Bureau.
The effect of this reguirement is to reguire eventual attainment of the Gold Book
levels, while allowing consideration of the site specific stream guality (% the mean
instream concentration). As the guality of the stream improves due to control of other
sources, dischargers will be reguired to improve the guality of their discharges down to
the Gold Book levels.
Table 26 of the ROD identifies surface water standards which must be met in-stream near
the site for remedial action to be complete. These standards should be met as soon as
feasible and maintained once they are met. Table 27identifies standards for point source
discharges and run-off water for actions at the site, and these standards must be met
for any discharge prior to discharge.
Short term exceedances of the standards associated with construction activities and
environmental remediation may be allowed. In-stream standards identified in Table 26
are to be met as soon as feasible and maintained thereafter, and consistent compliance
with the standards is a necessary component of remedial action completion. However,
activities at the Lower Area One operable unit of the Silver Bow Creek NPL site,
including possible dewatering at LAO, may influence the hydrological balance of the
area and cause temporary increases in organic contamination in Silver Bow Creek above
current conditions and the Table 26 standards. Such exceedances shall not be considered
a violation of the Table 26 in-stream standards, so long as Best Management Practices
are implemented to avoid or minimize such increases at both Lower Area One and the
Montana Pole site during dewatering. This determination is consistent with the
provisions of Chapter 340, Section 2, Laws of Montana 1993 and is consistent with a
temporary ARAR waiver found in section 121(d)(4)(A) and (C) of CERCLA, 42 U.S.C.
9621 (d) (4) (A) and (C) .
I classification standards also include the following criteria:
1. Dissolved oxygen concentration must not be reduced below 3.0 milligrams per
liter.
2. Hydrogen ion concentration (Ph) must be maintained within the range of 6.5 to
9.5.
3. No increase in naturally occurring turbidity, temperature, concentrations of
sediment and settleable solids, oils, floating solids, or true color is allowed
which will or is likely to create a nuisance or render the waters harmful,
detrimental, or injurious to public health, recreation, safety, welfare,
livestock, wild animals, birds, fish or other wildlife.
4. No discharges of toxic or deleterious substances may commence or continue which
lower or are likely to lower the overall water guality of these waters.
Additional standards for any discharge to surface waters are included in:
ARM 16.20.631 (Applicable), which reguires that, in designing a disposal system for
industrial waste,[44] 44 Section 75-5-103, MCA, defines "Industrial waste" as
"any waste substance from the process of business or industry or from the development of
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any natural resource, together with any sewage that may be present." stream
flow dilution reguirements must be based on the minimum consecutive 7-day average flow
which may be expected to occur on the average of once in 10 years.
ARM 16.20.633 (Applicable), which prohibits discharges containing substances that will:
(a) settle to form objectionable sludge deposits or emulsions beneath the surface of
the water or upon adjoining shorelines:
(b) create floating debris, scum, a visible oil film (or be present in concentrations
at or in excess of 10 milligrams per liter) or globules of grease or other
floating materials;
(c) produce odors, colors or other conditions which create a nuisance or render
undesirable tastes to fish flesh or make fish inedible;
(d) create concentrations or combinations of materials which are toxic or harmful to
human, animal, plant or aguatic life;
(e) create conditions which produce undesirable aguatic life.
ARM 16.20.925 (Applicable), which adopts and incorporates the provisions of 40 C.F.R.
Part 125 for criteria and standards for the imposition of technology-based treatment
reguirements in MPDES permits. Although the permit reguirement would not apply to
on-site discharges, the substantive reguirements of Part 125 are applicable, i.e., for
toxic and nonconventional pollutants treatment must apply the best available technology
economically achievable (BAT); for conventional pollutants, application of the best
conventional pollutant control technology (BCT) is reguired. Where effluent
limitations are not specified for the particular industry or industrial category at
issue, BCT/BAT technology-based treatment reguirements are determined on a case by case
basis using best professional judgment (BPJ). See CERCLA Compliance with Other Laws
Manual, Vol. I, August 1988, p. 3-4 and 3-7.
3.1.1.2 Montana Groundwater Pollution Control System (Applicable)
ARM 16.20.1002 (Applicable) classifies groundwater into Classes I through IV based on
the present and future most beneficial uses of the groundwater, and states that
groundwater is to be classified according to actual guality or actual use, whichever
places the groundwater in a higher class. Class I is the highest guality class; class IV
the lowest. The groundwater at the Montana Pole site is at least Class II groundwater.
ARM 16.20.1003 (Applicable) establishes the groundwater guality standards applicable
with respect to each groundwater classification. Concentrations of dissolved substances
in Class I or II groundwater (or Class III groundwater which is used as a drinking water
source) may not exceed Montana MCL values for drinking water. This reguirement
effectively makes the current MCL values applicable and not just relevant and
appropriate reguirements. Concentrations of other dissolved or suspended substances must
not exceed levels that render the waters harmful, detrimental or injurious to public
health. Maximum allowable concentration of these substances also must not exceed acute
or chronic problem levels that would adversely affect existing or designated beneficial
uses of groundwater of that classification.
The range of MCLs specified by Montana law is much more limited than the federal MCLs
and does not include many of the primary contaminants of concern at the Montana Pole
site. The groundwater standards that are specified, including the Montana MCLs for
arsenic, cadmium, chromium, lead, benzene and para-dichlorobenzene, are to be attained
throughout the contaminated plume. If such standards are not attainable, an ARAR waiver
may be appropriate.
ARM 16.20.1011 (Applicable) provides that any groundwater whose existing guality is
higher than the standard for its classification must be maintained at that high guality
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unless the board is satisfied that a change is justifiable for economic or social
development and will not preclude present or anticipated use of such waters.
3.2 MONTANA LOCATION-SPECIFIC ARARS
3.2.1 Floodplain and Floodway Management
3.2.1.1 Floodplain and Floodway Management Act (Applicable or Relevant and
Appropriate)
Section 76-5-401, MCA, (Applicable) specifies the uses permissible in a floodway and
generally prohibits permanent structures, fill, or permanent storage of materials or
eguipment.
Section 76-5-402, MCA, (Applicable) specifies uses allowed in the floodplain, excluding
the floodway, and allows structures meeting certain minimum standards.
Section 76-5-403, MCA, (Applicable) lists certain uses which are prohibited in a
designated floodway, including:
1. any building for living purposes or place of assembly or permanent use by human
beings,
2. any structure or excavation that will cause water to be diverted from the
established floodway, cause erosion, obstruct the natural flow of water, or
reduce the carrying capacity of the floodway, or
3. the construction or permanent storage of an object subject to flotation or
movement during flood level periods.
3.2.1.2 Floodplain Management Regulations (Applicable or Relevant and Appropriate)
ARM 36.15.216 (Relevant and Appropriate) specifies factors to consider in determining
whether a permit should be issued to establish or alter an artificial obstruction or
nonconforming use in the floodplain or floodway. While permit reguirements are not
directly applicable to activities conducted entirely on site, the criteria used to
determine whether to approve establishment or alteration of an artificial obstruction or
nonconforming use should be applied by the decision-makers in evaluating proposed
remedial alternatives which involve artificial obstructions or nonconforming uses in the
floodway or floodplain. Thus the following criteria are relevant and appropriate
considerations in evaluating any such obstructions or uses:
1. the danger to life and property from backwater or diverted flow caused by the
obstruction;
2. the danger that the obstruction will be swept downstream to the injury of others;
3. the availability of alternative locations;
4. the construction or alteration of the obstruction in such a manner as to lessen
the danger;
5. the permanence of the obstruction; and
6. the anticipated development in the foreseeable future of the area which may be
affected by the obstruction.
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ARM 36.15.603 (Relevant and Appropriate) provides that proposed diversions or changes in
place of diversion must be evaluated by the DNRC to determine whether they may
significantly affect flood flows and, therefore, reguire a permit. While permit
reguirements are not applicable for remedial actions conducted entirely on site, the
following criteria used to determine when a permit shall not be granted are relevant and
appropriate:
1. the proposed diversion will increase the upstream elevation of the 100- year
flood a significant amount (% foot or as otherwise determined by the permit
issuing authority);
2. the proposed diversion is not designed and constructed to minimize potential
erosion from a flood of 100-year freguency; and
3. any permanent diversion structure crossing the full width of the stream channel
is not designed and constructed to safely withstand up to a flood of 100-year
freguency.
ARM 36.15.604 (Relevant and Appropriate) precludes new construction or alteration of an
artificial obstruction that will significantly increase the upstream elevation of the
flood of 100-year freguency (% foot or as otherwise determined by the permit issuing
authority) or significantly increase flood velocities.
ARM 36.15.605(1) (Relevant and Appropriate) and ARM 36.15.605(2) (Applicable) enumerate
artificial obstructions and nonconforming uses that are prohibited within the designated
floodway except as allowed by permit and includes "a structure or excavation that will
cause water to be diverted from the established floodway, cause erosion, obstruct the
natural flow of water, or reduce the carrying capacity of the floodway ... ." Solid and
hazardous waste disposal and storage of toxic, flammable, hazardous, or explosive
materials are also prohibited.
ARM 36.15.606 (Relevant and Appropriate) enumerates flood control works that are allowed
within designated floodways pursuant to permit. Although the permit reguirements are
not applicable for activities conducted entirely on site, the following conditions are
relevant and appropriate:
1. flood control levies and flood walls are allowed if they are designed and
constructed to safely convey a flood of 100-year freguency and their cumulative
effect combined with allowable flood fringe encroachments does not increase the
unobstructed elevation of a flood of 100-year freguency more than % foot at any
point;
2. riprap, if not hand placed, is allowed if it is designed to withstand a flood of
100-year freguency, does not increase the elevation of the 100-year freguency
flood, and will not increase erosion upstream, downstream, or across stream from
the riprap site;
3. channelization projects are allowed if they do not significantly increase the
magnitude, velocity, or elevation of the flood of 100-year freguency downstream
from such projects;
4. dams are allowed if they are designed and constructed in accordance with approved
safety standards and they will not increase flood hazards downstream either
through operational procedures or improper hydrologic design.
ARM 36.15.703 (Applicable) is applicable in flood fringe areas (i.e., areas in the
floodplain but outside of the designated floodway) of the site and prohibits, with
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limited exceptions, solid and hazardous waste disposal and storage of toxic, flammable,
hazardous, or explosive materials.
3.2.1.3 Solid Waste Management Regulations (Applicable)
ARM 16.14.505 (Applicable), in establishing standards for solid waste disposal sites,
provides that such sites may not be located in a 100 year floodplain.
3.2.2 Natural Streairibed and Land Preservation Standards (Applicable)
ARM 36.2.404 (Applicable) establishes minimum standards which would be applicable if a
remedial action alters or affects a streambed, including any channel change, new
diversion, riprap or other stream bank protection project, jetty, new dam or reservoir
or other commercial, industrial or residential development. No such project may be
approved unless reasonable efforts will be made consistent with the purpose of the
project to minimize the amount of stream channel alteration, insure that the project
will be as permanent a solution as possible and will create a reasonably permanent and
stable situation, insure that the project will pass anticipated water flows without
creating harmful erosion upstream or downstream, minimize turbidity, effects on fish and
aguatic habitat, and adverse effects on the natural beauty of the area and insure that
streambed gravels will not be used in the project unless there is no reasonable
alternative. Soils erosion and sedimentation must be kept to a minimum. See also
75-7-102, MCA.
3.3 MONTANA ACTION-SPECIFIC ARARS
In the following action-specific ARARs, the nature of the action triggering
applicability of the reguirement is stated in parenthesis as part of the heading for
each reguirement.
3.3.1. Water Quality
3.3.1.1 Groundwater Act (Applicable) (Construction and maintenance of groundwater
wells)
Section 85-2-505, MCA, (Applicable) precludes the wasting of groundwater. Any well
producing waters that contaminate other waters must be plugged or capped, and wells must
be constructed and maintained so as to prevent waste, contamination, or pollution of
groundwater.
3.3.1.2 Public Water Supply Regulations (Applicable) (Reconstruction or
modification of public water or sewer lines on the site)
If remedial action at the site reguires any reconstruction or modification of any public
water supply line or sewer line, the construction standards specified in ARM
16.20.401(3) (Applicable) must be observed. A public sewerline crosses the Montana Pole
site, and the sewer line bedding is considered a potential pathway of contamination.
3.3.2 Air Quality[45] 45 The air guality ARARs included in this analysis are
identified on the assumption that no remedial action at the site will constitute a
"major stationary source," or "major modification," as defined in ARM 16.8.921. Should
any part of a remedy constitute such a source, some additional reguirements would be
applicable, including the ambient air increments of ARM 16.8.925 et seg.
Similarly, if any part of a remedy should constitute a new or altered source of air
pollution which has the potential to emit more than 25 tons per year of any pollutant
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addressed by the Clean Air Act regulations, the owner or operator must install the
maximum air pollution control capability which is technically practicable and
economically feasible, as provided by ARM 16.8.1103 (best available control technology
shall be utilized).
3.3.2.1 Air Quality Regulations (Applicable) (Excavation/ear thmoving;
transportation; incineration; storage of petroleum distillates)
Dust suppression and control of certain substances likely to be released into the air as
a result of earth moving, transportation and similar actions may be necessary to meet
air quality requirements. The ambient air standards for specific contaminants and for
particulates are set forth in the federal contaminant-specific section above.
Additional air quality regulations under the state Clean Air Act, 75-2-101 et seq., MCA,
are discussed below.
ARM 16.8.1302 (Applicable) lists certain wastes that may not be disposed of by open
burning[46], 46 "'Open burning' means combustion of any material directly in
the open air without a receptacle, or in a receptacle other than a furnace, multiple
chambered incinerator or wood waste burners ..." ARM 16.8.1301 (5) . including
oil or petroleum products, RCRA hazardous wastes, chemicals, and treated lumber and
timbers. Any waste which is moved from the premises where it was generated and any
trade waste (material resulting from construction or operation of any business, trade,
industry or demolition project) may be open burned only in accordance with the
substantive requirements of 16.8.1307 or 1308.
ARM 16.8.1401(3) and (4) (Applicable) states that no person shall cause or authorize the
production, handling, transportation or storage of any material unless reasonable
precautions to control emissions of airborne particulate matter are taken.
ARM 16.8.1404 (Applicable) states that "no person may cause or authorize emissions to be
discharged in the outdoor atmosphere ... that exhibit an opacity of twenty percent (20%)
or greater averaged over six consecutive minutes."
ARM 16.8.1406 (Applicable) prohibits certain emissions from incinerators, including
emissions of particulate matter in excess of 0.10 grains per standard cubic foot of dry
flue gas, adjusted to twelve percent carbon dioxide and calculated as if no auxiliary
fuel had been used, emissions which exhibit an opacity of ten percent (10%) or greater
averaged over six consecutive minutes.
Two bills were passed by the 53rd Montana Legislature directly addressing the issue of
incineration of wastes. Section 75-2-215, MCA, as amended by 1993 Laws of Montana.
Chapter 129, provides that solid of hazardous wastes may be incinerated only after a
determination that the projected emissions and ambient concentrations of air pollutants
from the proposed incineration will constitute a negligible risk to the public health,
safety, and welfare, and to the environment, and such incineration shall require the
application of air pollution control equipment, engineering, or other operating
procedures as necessary to provide reductions of air pollutants, equivalent to or more
stringent than those achieved through the best available control
technology.
Also, in order to minimize the potential creation or release of dioxins, furans, heavy
metals or carcinogens, Chapter 639, Laws of Montana 1993, requires the Board of Health
to adopt rules that require hazardous waste incinerators to achieve the lowest
achievable emission rate, except when best available control technology is adequate to
prevent exceeding established federal allowable daily intake standards for dioxins,
furans, heavy metals, and other carcinogens. Although the rules have not yet been
promulgated, the directive is sufficiently clear that, if wastes were incinerated
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on-site, this standard for emissions should be met. This act also sets out a number of
additional administrative requirements, including additional public notice and meeting
requirements and procedures for the monitoring, testing, and inspection of the waste
stream, including possible precursors to the formation of dioxins, furans, and
carcinogens. Although these administrative requirements are not ARARs, they should be
considered if any on-site incineration were to become necessary.
ARM 26.4.761 (Relevant and Appropriate) specifies measures that must be implemented to
control fugitive dust emissions during certain mining and reclamation activities. Such
measures are relevant and appropriate requirements to control fugitive dust emissions
during excavation, earth moving and transportation activities conducted as part of the
remedy at the site.
3.3.2.2 Reclamation and Revegetation Requirements (Relevant and Appropriate)
(Excavation)
ARM 26.4.501 and 501A (Relevant and Appropriate) give general backfilling and final
grading requirements.
ARM 26.4.514 (Relevant and Appropriate) sets out contouring requirements.
ARM 26.4.519 (Relevant and Appropriate) provides that an operator may be
required to monitor settling of regraded areas.
ARM 26.4.638 (Relevant and Appropriate) specifies sediment control measures to be
implemented during operations.
ARM 26.4.702 (Relevant and Appropriate) requires that during the redistributing and
stockpiling of soil (for reclamation):
1. regraded areas must be deep-tilled, subsoiled, or otherwise treated to eliminate
any possible slippage potential, to relieve compaction, and to promote root
penetration and permeability of the underlying layer; this preparation must be
done on the contour whenever possible and to a minimum depth of 12 inches;
2. redistribution must be done in a manner that achieves approximate uniform
thicknesses consistent with soil resource availability and appropriate for the
postmining vegetation, land uses, contours, and surface water drainage systems;
and
3. redistributed soil must be reconditioned by subsoiling or other appropriate
methods.
ARM 26.4.703 (Relevant and Appropriate) When using materials other than, or along with,
soil for final surfacing in reclamation, the operator must demonstrate that the material
(1) is at least as capable as the soil of supporting the approved vegetation and
subsequent land use, and (2) the medium must be the best available in the area to
support vegetation. Such substitutes must be used in a manner consistent with the
requirements for redistribution of soil in ARM 26.4.701 and 702.
ARM 26.4.714 (Relevant and Appropriate) requires use of a mulch or cover crop or both
until an adequate permanent cover can be established. Use of mulching and temporary
cover may be suspended under certain conditions. ARM 26.4.716 (Relevant and
Appropriate) establishes the required method of revegetation, and provides that
introduced species may be substituted for native species as part of an approved plan.
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ARM 26.4.718 (Relevant and Appropriate) requires the use of soil amendments and other
means such as irrigation, management, fencing, or other measures, if necessary to
establish a diverse and permanent vegetative cover.
3.4 OTHER LAWS
The following "other laws" are included here to provide a reminder of other legally
applicable requirements for actions being conducted at the site. They do not purport to
be an exhaustive list of such legal requirements, but are included because they set out
related concerns that must be addressed and, in some cases, may require some advance
planning. They are not included as ARARs because they are not "environmental or
facility siting laws." As applicable laws other than ARARs, they are not subject to
ARAR waiver provisions.
Section 121 (e) of CERCLA exempts removal or remedial actions conducted entirely on an
NPL site from federal, state or local permit requirements, and this exemption appears
broad enough to cover even permits required under "other laws." However, the
administrative/substantive distinction used in identifying ARARs applies only to ARARs
and not to other applicable laws. Thus even the administrative requirements, e.g.,
notice requirements, of these other laws must be complied with in this action.
Similarly, fees that are based on something other than issuance of a permit are
applicable.
3.4.1 Groundwater Act
Section 85-2-516, MCA, states that within 60 days after any well is completed a well log
report must be filed by the driller with the DNRC and the appropriate county clerk and
recorder.
3.4.2 Water Rights
Section 85-2-101, MCA, declares that all waters within the State are the State's
property, and may be appropriated for beneficial uses. The wise use of water resources
is encouraged for the maximum benefit to the people and with minimum degradation of
natural aquatic ecosystems.
Parts 3 and 4 of Title 85, MCA, set out requirements for obtaining water rights and
appropriating and utilizing water. All requirements of these parts are laws which must
be complied with in any action using or affecting waters of the state. Some of the
specific requirements are set forth below.
Section 85-2-301, MCA, of Montana law provides that a person may only appropriate water
for a beneficial use.
Section 85-2-302, MCA, specifies that a person may not appropriate water or commence
construction of diversion, impoundment, withdrawal or distribution works therefor except
by applying for and receiving a permit from the Montana Department of Natural Resources
and Conservation. While the permit itself may not be required under federal law
appropriate notification and submission of an application should be performed and a
permit should be applied for in order to establish a priority date in the prior
appropriation system. A 1991 amendment imposes a fee of $1.00 per acre foot for
appropriations of ground water, effective until July 1, 1993.
Section 85-2-306, MCA, specifies the conditions on which groundwater may be
appropriated, and, at a minimum, requires notice of completion and appropriation within
60 days of well completion.
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Section 85-2-311, MCA, specifies the criteria which must be met in order to appropriate
water and includes requirements that:
1. there are unappropriated waters in the source of supply;
2. the proposed use of water is a beneficial use; and
3. the proposed use will not interfere unreasonably with other planned uses or
developments.
Section 85-2-402, MCA, specifies that an appropriator may not change an appropriated
right except as provided in this section with the approval of the DNRC.
Section 85-2-412, MCA, provides that, where a person has diverted all of the water of a
stream by virtue of prior appropriation and there is a surplus of water, over and above
what is actually and necessarily used, such surplus must be returned to the stream.
3.4.3 Occupational Health Act, 50-70-101 et seq., MCA
ARM S 16.42.101 addresses occupational noise. In accordance with this section, no
worker shall be exposed to noise levels in excess of the levels specified in this
regulation. This regulation is applicable only to limited categories of workers and for
most workers the similar federal standard in 29 CFR S 1910.95 applies.
ARM S 16.42.102 addresses occupational air contaminants. The purpose of this rule is to
establish maximum threshold limit values for air contaminants under which it is believed
that nearly all workers may be repeatedly exposed day after day without adverse health
effects. In accordance with this rule, no worker shall be exposed to air contaminant
levels in excess of the threshold limit values listed in the regulation. This regulation
is applicable only to limited categories of workers and for most workers the similar
federal standard in 29 CFR S 1910.1000 applies.
3.4.4 Federal Occupational Health and Safety Act
On-site work must comply with the provisions of 29 CFR S 1910.95.
3.4.5 Montana Safety Act
Sections 50-71-201, 202 and 203, MCA, state that every employer must provide and
maintain a safe place of employment, provide and require use of safety devices and
safeguards, and ensure that operations and processes are reasonably adequate to render
the place of employment safe. The employer must also do every other thing reasonably
necessary to protect the life and safety of its employees. Employees are prohibited from
refusing to use or interfering with the use of safety devices.
3.4.6 Employee and Community Hazardous Chemical Information Act
Sections 50-78-201, 202, and 204, MCA, state that each employer must post notice of
employee rights, maintain at the work place a list of chemical names of each chemical in
the work place, and indicate the work area where the chemical is stored or used.
Employees must be informed of the chemicals at the work place and trained in the proper
handling of the chemicals.
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APPENDIX B
ADMINISTRATIVE RECORD INDEX
Locations of the Administrative Record:
Montana Department of Health and Environmental Sciences
Solid and Hazardous Waste Bureau
Superfund Program
616 Helena Avenue, Room 302
Helena, Montana 59601
Montana Tech Library
West Park Street
Butte, Montana 59701
Updated: September 21, 1993
Administrative Record Site File Index
Montana Pole Superfund Site
Administrative Record For
Selection of Remedial Action
Notes:
1. Only sections appearing below in Bold type are presently contained in the
administrative record. Those listings appearing in ordinary type are anticipated
for a later stage in the proceedings.
2. The Removal Response section consists primarily of documents appearing in the EPA
Administrative Record for the Removal Actions. This EPA record was compiled
during the removal action conducted at the Montana Pole site in 1985-1987 and
during the removal action conducted at the site in 1992-1993. For consistency,
these files are arranged in this record essentially the same as they appear in
the EPA record.
1.0 SITE IDENTIFICATION
1.01 Background Information including RCRA
1.02 Site Inspection/Site Investigation Reports
1.03 Preliminary Assessment (PA) Report
1.04 Sampling and Analytical Data
1.05 Site Photographs/Slides
2 . 0 REMOVAL RESPONSE
2.01 Site Investigation
2.02 Pollution Reports (POLREPS)
2 . 03 Action Memorandum
2.04 Work Plans
2.05 Site Safety
2.06 Applications/Permits
2.07 Meetings/Schedules
2.0 (Removal Response)
2.08 Sampling Plans
2.09 Sampling and Analysis Data/Chain of Custody Forms
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2.10 Technical Assistance Team (TAT) Report
2.11 Engineering Evaluation/Cost Analysis (EE/CA)
2.12 Emulsion/Recovery System
2.13 Status Reports/Monthly Reports
2.14 Logbooks/Notes
2 .15 Community Relations
2.16 Reguests under the Freedom of Information Act (FOIA)
2.17 General Correspondences
2.18 Liguid Dioxin Disposal Proposals
2.19 Technical Information
2.20 Post Removal Issues
2.21 1992 Time Critical Removal Action (TCRA)
2. 21.1 General Correspondence
2.21.2 Pollution Reports (POLREPS)
2.21.3 Action Memorandum
2.21.4 ARCO Submittal for Administrative Record
2.21.5 Community Relations
2.21.6 Status Reports/Monthly Reports
2.21.7 Engineering Evaluation/Cost Analysis (EE/CA)
3.0 RI/FS PLANNING
3.01 RI/FS Scoping
3.02 Workplans
3.02.1 Volume I
3.02.2 Volume II (Includes Sampling and Analysis Plan and Schedule)
3.02.3 Standard Operating Procedures (SOPs)
3.02.4 Supplemental or Additional Work Plans
3.02.5 Dismantled Eguipment Work Plans
3.03 Quality Assurance Project Plan (QAPP)
3.04 Data Management Plan
3.05 Site Management Plan
3.06 Health and Safety Plan
3.07 Review Comments
3.08 Response to Comments
4.0 REMEDIAL INVESTIGATION
4.01 Historical and Archaeological Resources Reports
4 . 02 Endangered Species Report
4 . 03 Floodplain Report
4.04 Wetland Report
4.05 Monthly Reports
4.06 Sampling and Analysis Data/Chain of Custody Forms
4.06.1 Round 1 Raw Data
4.06.2 Round 1 and 2 Data Validation Report
4.06.3 Round 2 Raw Data
4.06.4 Supplemental Raw Data
4.06.5 Supplemental Data Validation Reports
4.06.6 Split Sample Data
4 . 07 Remedial Investigation Reports
4.07.1 Preliminary Draft RI Report
4.07.2 Draft RI Reports
4.07.3 Final RI Report
4.08 Review Comments
4.09 Response to Comments
5.0 FEASIBILITY STUDY
5.01 Technologies Screening Document
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5.02 Alternatives Screening Document
5.03 Treatability Work Plan
5.04 Treatability Reports
5.05 ARAR Determinations
5.05.1 Preliminary Identification of Contaminant-specific ARARs
5.05.2 ARCO ARARs Scoping Documents
5.05.3 Screening and Description of Potential ARARs
5.06 Institutional Controls Reports
5.07 Preliminary Remediation Goals
5.08 Draft FS Reports
5.09 Final FS Report
5.10 ARCO RI/FS Position Paper
* 5.11 Proposed Plan
5.12 Public Comments
6.0 RECORD OF DECISION (ROD)
* 6.01 ROD (Declaration and Decision Summary)
6.02 Responsiveness Summary
7.0 STATE COORDINATION
7.01 EPA/State Cooperative Agreement
8 . 0 ENFORCEMENT
8.01 ARCO/State Administrative Order on Consent
* 8.02 PRP Responses
8.03 Notice Letters
8.04 Enforcement History-Correspondence [Miner's Bank prior to 1992] (may
contain non-Miner's Bank correspondence in 1992 and later)
Pleadings in Injunction Action (State v. Miners Bank and Montana Pole)
Miner's Bank Liability/Settlement (1992 & forward) 8.07 Complaint and
Depositions (Montana Pole v. Laucks)
9.0 PUBLIC HEALTH AND ENVIRONMENTAL ASSESSMENTS (PHEA)
9.01 Agency for Toxic Substances and Disease Registry (ATSDR) Health Assessments
9.02 Preliminary Endangerment Assessment (PEA)
9.03 ARCO Risk Assessment Scoping Documents
9.04 Baseline Risk Assessment
9.04.1 Baseline Risk Assessment Report (COM, August 1992)
9.04.2 Revised Final Baseline Risk Assessment
10.0 NATURAL RESOURCE TRUSTEES
10.01 Notices Issued
10.02 Correspondence
11.0 PUBLIC PARTICIPATION
11.01 Community Relations Plan
11.02 Press Releases
11.03 Press Clipping
11.04 Fact Sheets
11.05 Public Notice(s) (Availability of the Administrative Record File and
Proposed Plan, Public Hearings)
11.06 Public Hearings/Transcripts
11.07 Documentation of Other Public Meetings
11.08 Comments on Administrative Record
11.09 Response to Comments on Administrative Record
12.0 TECHNICAL SOURCES AND GUIDANCE DOCUMENTS
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12.01 State Guidance/Bibliography of Guidance Documents
12.02 EPA Removal Action Administrative Record Index
12.03 Soil Washing Studies
12.04 Other Technical Information
* Additional information is located in a confidential file. A summary or explanation of
this material is included in this record.
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