United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R08-89/022
December 1988
SEP A
Superfund
Record of Decision
Libby Ground Water, MT
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REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R08-89/022
X RsdptanT* Accession Mo.
4. TMsMdSUMtss
SUPERFUND RECORD OF DECISION
Libby Ground Water Contamination, MT
I Second Remedial Action
Autttofts)
S. Report Otts
12/30/88
s. Performing Orgsnlzstlon Rent No.
9. PsrfoiiiibigOrgalnlallofiNeins end Address
ia ProteetfTMk/Work Un« No.
11. Contract(C) or Grmt(G) No.
(C)
12.
Org.
•tionNe
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type ol Report A Period Covered
800/000
14.
IS. Supptemmttry Note*
18. AbsMct (Limit: 200 words)
The Libby Ground Water Contamination site (also known as the Champion Mill site or the
Libby Pesticide site) is located on the Champion International Corporation lumber and
plywood mill in the City of Libby, Lincoln County, Montana. Champion is the third owner
of the facility, which has been in operation since 1946. The area around the site
includes residential areas and businesses. The site is bordered on the west by Flower
eek, on the east by Libby Creek, and on the north by the Kootenai River. The city and
rrounding areas have a population of approximately 11,000. The contaminated
soil/source area is within the confines of the facility; however, ground water
contamination extends well into the City of Libby. Wood treating fluids and their
constituents, including creosote and PCP, are the contaminants of concern at the site.
They are found in soil and sediments at several different locations, including former
waste pits, tank storage areas, and butt dip and treatment sites. The contamination is
the result of spent fluids, overflow of treatment tanks, and spills. In addition to
creosote and PCP, certain carrier fuels or oils were used at the site and contributed
VOC contaminants. Investigations at the site were initiated by the State in 1979 after
a residential well was found to smell of creosote. A ROD signed in September 1986
provided an alternate water source to residents whose wells were contaminated. The site
(See Attached Sheet)
17. Document Anslysls s. Descriptor*
Record of Decision - Libby Ground Water Contamination,
Second Remedial Action
Contaminated Media: soil, debris, gw
Key Contaminants: VOCs, organics (PAHs), oil
b. Menansrs/Opsn-Ended Terms
MT
19. Security CtMS (This Report)
None
20. Security OMS (This Pigs)
None
21. No. ofPiges
104
22. Pries
(SssANSlZU.18)
Stf Instruction* on /tenors*
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EPA/ROD/R08-89/022
Libby Ground Water Contamination, MT
Second Remedial Action
Abstract (continued)
has been divided into three operable units; however, they require concurrent
remediation. The operable units are the soil/source area within the confines of the
facility; the upper aquifer, historically used for drinking water and irrigation but
currently severely contaminated; and the lower aquifer, highly contaminated with oil
and non-aqueous phase liquids (NAPL). The primary contaminants of concern affecting
the soil, sediments, and ground water at the site are VOCs including benzene; other
organics including dioxin, PAHs (creosote constituents), and PCP; metals including
arsenic; and oil.
The selected remedial actions for this site have been developed based on operable
units. The selected remedial action for the soil/source area includes excavation and
consolidation of approximately 30,000 yd3 of unsaturated soil and debris in the waste
pit area, followed by a two-step enhanced biodegradation process composed of enhanced
natural biodegradation and subsequent transfer to a land treatment unit consisting of a
3.5-acre lined treatment cell for land farming and final deposition; in situ
bioremediation treatment of saturated- soil in the waste disposal pit using a closed
loop system involving ground water pumping and physical treatment in a fixed bed
bioreactor with reinjection through a rock percolation bed, and in situ biodegradation
stimulation to prevent further leaching of source material to ground water (recovered
NAPL will be processed in an oil/water separation and stored onsite for recycling and
incineration); and capping of the waste pit, butt dip, and tank farm areas. The
selected remedial action for the upper aquifer includes in situ ground water
oremediation of the upper aquifer that is separate from the process used in the
urated zone of the waste pit area. The selected remedial.action for the lower
ifer includes implementation of a pilot test for the oil-contaminated lower aquifer
using biorestoration in conjunction with oil recovery and oil dispersion techniques
(this is an interim remedy for the lower aquifer); implementation of institutional
controls including deed, land use, and ground water restrictions; and onsite ground
water monitoring. The estimated present worth cost of this remedial action is
$5,777,000 with annual O&M of $670,200 for year 2, $521,200 for years 3-5, $232,200 for
years 6-8, and $80,000 for 9-30.
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U.S. EPA Region VIII
Montana Operations Office
RECORD OF DECISION
Libby Ground Water Superf und Site
Lincoln County, Montana
December 1988
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Record of Decision
Declaration
Ubby Ground Water Site. Ubby. Montana
Statement of Basis and Purpose
This decision document represents the selected remedial
action for the Lieby Ground Water Superfund Site ("Libby Site"),
in Libby, Montana developed in accordance .with trie Comprehensive
Environmental Response, Compensation, and Liability Act of ^980,
as amended by the Superfund Amendments and Reauthorization Act
and, to the extent practicable, the National Contingency Plan.
This decision is based on the administrative record for the
site.* 3y signature below, the State of Montana concurs in this
Record of Decision. All determinations reached in the Record of
Decision were made in consultation with the State of Montana,
which has participated fully in the development of this Record of
Decision.
Description of the Selected Remedy
I. The response action that the Environmental Protection Agency
has selected was developed as a final remediation strategy for
clean up of soils and source areas, and remediation of the upper
aquifer. The lower aquifer action is an interim remedy. The"
final remedy for that action will ultimately be determined at a
later date, although this Record of Decision develops the oasis
for the final remedy determination. The response selected
consists of three major sub-actions within the overall response
action, each of which is described in detail ir. the Decision
Summary. Each of the sub-actions units poses near and long-term
public health and environmental threats of varvir.a magnitude.
Soils & Source Areas
Soils in some areas of the Libby site are contaminated bv
various organic and inorganic wood treating compounds.
Contaminated soils in the unsaturated and saturated n~r.es
present a public health threat via direct contact and
ingestion. They also pose a direct environmental threat and
public health threat because they act as source .r.ater.ials by
•releasing contaminants to the ground water.
Ground Water/Upper Aquifer
Ground water in the upper aquifer emanating from the Libbv
site is contaminated primarily by organic wood treating
compounds. The ground water poses a public health threat
due to the possibility of ingestion of water ta
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r.eaitr, t.-.rsat 1 =
for irrigation of
at ion may pose an
slow advancement
Ground Water/Lower Aquifer
rood products. The
•environmental threat
:f the ciume toward ~
C •-' -a t 2 r ~ i V
•ground vate:
because of
he Koctenai
. s n'
•a i-
Ground water IT. the lower aquifer
treating compounds as well, in di
similar to the upper aquifer. In
non-aqueous phase liquids (NAPL)
lower aquifer,, providing a long t
species contamination. Because o
lower aquifer ground water poses
threat than the upper aquifer. H
exposure to contaminants from the
because there are no waper wells
aquifer dcwngradient of the site
River.
CG
is contaminatea witr.
ssclved concentrations
addition, large volumes o:
are also present in the
erm source of dissolved
f the NAPL presence, the
a greater potential health
owever, the potential for
lower aquifer is very low
completed" in the lower
orior to the Koote.nai
II. The major components of the selected remedy and
concerns that they address are as follows:
Concern
Contaminated
Soils
Response Action
Contaminated soils from the tank farm area, butt
dip treatment area and any other source locations
as may be identified will be excavated and placed
in the waste pit area, which also contains contam-
inated soils and debris. Contaminated soils from
the unsaturated zone will undergo a two-step
enhanced biodegradation treatment. In this treat-
ment process, natural degradation of contaminants
•-ill be stimulated and accelerated using concen-
trated mixtures of microbes, nutrients and other
energy sources. _The initial treatment will be
conducted in the waste pit area. "pon reaching an
optimum contaminant degradation a lift of soils
will be transferred to the second phase treatment
cell which will also act as the final disposition
location. Eventually, all contaminated soils in
the waste pit above the saturated zone will be
removed to the final treatment location. The
treatment cell will be lined with low permeability
materials to resist leachate infiltration and
adsorb contaminants "from liquids. The bottom
barrier system will also assure no migration of
contaminants from the treatment ceil. After
contaminant concentrations have been reduced to
acceptable levels, a protective cap will be
installed over the second-phase treatment cell to
reduce surface water infiltration- and preclude
direct contact. Post closure care, including
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-on it or ing a .".a inspection, •••___ c-=
the treatment ceil after pi ace.Tent
A cc7ibir.at.icn of in-situ bicremediaticn treatment
:esses will be utilized to clearacie
:or.tamir.ants ir. the saturated icr.e c: the waste
oit area. A closed loop, bacteria rich ground
water injection and extraction system will be tr.e
primary technique used to degrade contaminants
adsorbed on soil matrices and in oil product in
the saturated zone. Extraction wells will be
installed to remove NAPL from the source area.
Recovered NAPL will be processed in an oil/water
separator and stored on site for recycling or
incineration.
At completion, the waste pit area will be closed,
in accordance with P.CP.A closure requirements. A
protective cap will be required over the waste
pit, curt dip and tank farm areas. Post-closure
care, if appropriate, will be required for these
areas as well.
Upper Aquifer The oil recovery wells will also be used to
collect highly contaminated ground water, which
will undergo treatment in a fixed bed bioreactcr
prior to reinjection through a rock percolation
bed. This system will greatly reduce contaminant
migration outside of the immediate waste pit area
ground water system.
An in-situ, enhanced bicrestcraticn program,
separate from the processes employed to degrade
contamination in the saturated zone of the vaste
pit source area, will be initiated in the upper
aquifer to reduce contaminant levels. This
innovative treatment technology will achieve a
faster and more effective ground water cleanup
than traditional pump and treat systems because
contaminants in the dissolved phase, as well as
these adsorbed into aquifer matrices, will ce
degraded concurrently. Non-aqueous phase liquids
will also be degraded, but at a slower rate.
The in-situ treatment process will reduce contam-
ination in the upper aquifer to the required risk
and ARAR-based levels. The current prohibition c:
new use of the aquifer will continue until these
levels are achieved, as will the buy-water plan
approved in the 1st operable unit ROD.
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Lower Aquifer Efforts to ievelep an effective cil recovery
system for tne lower aquifer have ceen unsuc-
cessful to date. Extensive study has been devoted
to this issue during the RI/FS (see Appendix F of
the Feasibility Study Report). The lower aquifer,
which to EPA's knowledge has r.ot oeen used for
consumption purposes down-gradient of the site,
contains unknown quantities of oily product. The
complex hydrogeologic properties of the lower
aquifer indicate that attempts to withdraw oily
product using well developed oil reservoir
technologies would only be 50% effective at a
maximum. A 50% recovery efficiency would result
in little reduction of potential environmental
and/or public health threat.
However, EPA is not convinced that some methods to
remediate the lower aquifer are not feasible. The
Agency is therefore unwilling to dismiss the lower
aquifer under a no-action scenario at this time.
This remedy selection prescribes implementation of
a biorestoraticn test program similar in scope to
that conducted for the upper aquifer. The pilot
test will be conducted to determine if enhanced
biorestoration of the aquifer, in conjunction with
oil recovery and oil dispersion techniques, is an
effective method of remediation. This remedy also
includes continuation of the prohibition on well
drilling in the lower aquifer. At the conclusion
of the pilot program, a Record of Decision will be
issued which will select a final remedy for the
lower aquifer.
Ground Water There is currently a prohibition on the drilling
Restrictions of new water supply wells in the city of Libby.
This ordinance was passed by the City in support
of the September, 1986 Record of Decision for the
first operable unit. This selection of remedy
provides for continuation of that ordinance until
ground water is cleaned to acceptable levels. It
also identifies a potential need for a similar
prohibition in portions of Lincoln County outside
the city of Libby should the aquifer restoration
processes not degrade the contaminant plume prior
to migration (if moving) outside the city limits.
The prohibition on drilling in the upper aquifer
may be rescinded after risk and ARAR levels are
reached. The prohibition on drilling in the lower
aquifer will continue throughout the extent of the
treatment pilot program. The prohibition will ce
re-examined during the ROD for final remedy in the
lower aquifer. . •
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Monitoring
"his selection
f T
remedy requires active
5-Year
Review
Remedy
Deed
Restrictions
monitoring of remediation actions to assure
treatment effectiveness throughout the lifetime of
cell will ce recuired to determine if contaminants
are migrating. long term monitoring of lower and
upper aquifer water quality is also required to
determine further movement of contaminant plumes,
assure protection of public health and, if plumes
are shown to migrate,
the Kootenai River.
assess potential
lamaae
In accordance with'Section 121(G) of CERCLA this
selection of remedy calls for a review of the
remedial actions conducted at the Libby site five
•ears from implementation of remedial actions to
assure human health and the environment are being
protected. This review process will be required
only i.f a determination is made that hazardous
substances remain on-site above health based
levels. If the review determines that additional
action is required to protect public health and
the environment, EPA will take such action as is
appropriate. This review is in addition to the
remedy selection to be made at the conclusion of
the pilot study for the lower aquifer.
As part of the remedy for the soils operable unit,
deed restrictions will be required of the property
owner. These will require the property owner to
insert language in the current registered deed
which identifies the locations of hazardous
substances disposal and treatment areas, and
restricts the future use of these areas. .
Declarations
, i
The selected remedy for clean up of contaminated soils ar.c
ground water- in the upper aquifer is protective of human health
and the environment, is cost effective, and attains:Federal and
State requirements that are applicable or relevant and appro-
priate (ARAR) to this remedial action. Further discussion of one
ARAR, RCRA Land Disposal Restrictions, is warranted because
attainment of the ARAR will likely be achieved through a
variance.
According to EPA Land Disposal Restrictions for First Third
Scheduled Wastes, land disposal of RCRA KOCH wastes is prohicited
after August 5.. 1988, unless certain maximum concentration live Is
are met. Because bottom sediment sludges from treatment of vaste
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•- a t e r 3 : r c r. •- - c c. - c r e s e r .
pentachloropher.oi are present in the waste pit area at Liccy, and
these are considered !
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maximum extent: practicable.
Because this remedial action may result in hazardous
substances remaining on site at concentrations aocve health risk
levels, a review will be conducted within five years after
Commencement ~i remedial action to ensure that the remedy
continues to provide adequate protection of human health and the
environment. This review will look at the existing lower aquifer
program, and any new technologies for the site.
«
EPA will also evaluate other alternatives, including no
action and monitoring with institutional controls, after
completion of lower aquifer pilot treatment tests. A Record of
Decision will be issued at that time.
Signature
James J. Scherer Date
U.S. EPA Region VIII Administrator
In Concurrence
s >~.
•>-<' •*'.-.
John J. Drynan. M.D.. Director Date
Department of Health and Environmental Sciences
State of Montana
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Table of Contents
Record of Decision Summary
Chapter —7s
I Description of Site ' '
II Site History and Enforcement Activities 2
III Community Relations History 5
IV Scope and Role of Response Actions ^
V Summary of Site Characteristics 3
i. Contaminant Characterization 3
2. Extent of Contamination '0
VI Summary of Site Risks 1 3
i. Indicator Compounds 1 3
2. Toxicity Assessment M
3. Exposure Pathways '4
4. Risk Characterization: Soils/Source Areas '6
5. Environmental Risks: Soils/Source Areas '7
S. Risk Characterization: Upper' Aquifer 17
7. Risk Characterization: . Lower Aquifer '9
3. Environmental Risks: Ground Water '9
VII Documentation of' Significant Changes 10
,VIII Description of Alternatives 22
, 1. Operable Unit A - Soils/Source Areas 22
2. Operable Unit 3 - Upper Aquifer . 29
3. -Operable Unit C - Lower Aquifer 27
IX Summary of Comparative Analysis of Alternatives 43
1. Sub-Action A - Soils/Source Areas 44
2. Sub-Action B - Upper Aquifer . 47
3. Sub-Action C - Lower Aquifer 49
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•"haptgr • .- ic<
X Selected Remedies and Cleanup Determinations 31
i. Soils/Scarce Are.as Excavation and 51
Treatment Criteria
2. Ground Water Cleanup Levels - 'Jpper Aquifer 53
3. Ground Water Cleanup Levels - Lower Aquifer 55
XI The Statutory Determinations 55
• «
1. Protection of Human Health and • 55
the Environment
2. Attainment of ARARs 57
3. Cost Effectiveness 59
4. Utilization of Permanent Solutions, 50
Alternative Treatment or Resource Recovery
Technologies & the Preference for Treatment
XII References
Attachments
A. Responsiveness Summary
B. Administrative Record Index
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Record of Decision
Summary
Description of Site
The Libby Ground Water Superfund sits iaiso known as the
Champion Mill site or the Libby Pesticides site) is located in
the northwestern corner of Montana in the town of Libby, Lincc.n
C6cfnty (Figure 1 ). The surface expression of the site is owned
by Champion International Corporation and contaminant source
areas are within the confines of an active lumber and plywood
mill. The mill facilities are located en the eastern edge of the
city of Libby and are bounded on the east by Libby Creek, on the
south by private property, on the west by U.S. Highway 2 and on
the north by the kootenai River (Figure 2). The remainder of the
site consists of contaminated ground water extending well into
the city of Libby.
The city and surrounding areas have a population of
approximately 10,960 according to a 1380 census. Residential
neighborhoods and businesses are immediately adjacent to the
industrial property along the extent of the western boundary,
separated from the mill physically by fencing and usually
roadway.
Northwestern Montana is comprised of mountainous terrain,
heavily timbered with abundant surface water. The Cabinet
Mountains Wilderness is located west and south of Libby, the
Purcell Mountains to the north, and the Saiish Mountains are east
of the city. Much of the land in this part of Montana is
federally owned and administered by the Kootenai National Forest.
Locally, the site topography is flat, varying in elevation from
2,125 ft. mean sea level (msl) to about 2,070 msi. Average
annual rainfall for the last 25 years, measured at the U.S.
Forest Service Station, is IS.IO inches per year.
•
The predominant industries in the Libby area are timber
harvesting and processing, mining and recreation. Champion
International Corporation's Libby mill alone employs approxi-
mately 9* of the working force in Lincoln County. Mining is also
an economically important industry in this area, particularly for
silver and other precious metals in the Cabinet Range, and for
vermiculite at the W.R. Grace facility just northwest of Libby
across the Kootenai River. Tourism and recreational activities
such as hunting, fishing and boating also positively impact the
local economy.
Surface water is abundant in this part of Montana.
Typically, intermontane valleys contain small streams, recharged
by high-country snowpack, which feed into regionally important
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I i<|int> 3
MIOIH.C
LCAMV
AQUIIAMO
<40'- TO I
MlOOtt Lf AMY AQUITAMO
o
OIL ENCOUNTLREO IS A IIGHTfR THAN WATER PHASE
-------
UJ
CHAMPION
INTERNATIONAL
\
TANK FARM
AREA
BUTT DIP
AREA
i \
4/1
SMALL
UOG
PO40
WASTE PIT
AREA
\\
\ \
\\
Contaminated Soil Areas
250 500
— —
SCALE WFEET
N
^t
"•V'
.\
MS
Figure 4
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rivers. The city o: Libcy is cordered en t.-.e east cy Li-cy J.- = e.<
and the vest by Flower Creek, both of which rscr.arge the Xcctenai
River, the northern city boundary. Average flow of the Xootenai
varies frcm 20,000 cubic feet per second (cfs/1 to 20,000 cfs.
The hydrcgeclogica1 -. -round water regime cf the Libby area
is characterized by glacial, glacio-fluviai and alluvial deposits
which form a complex arrangement of inter fingered water bearing
and non-water bearing units. Two connected but hydrogeologically
differentiated aquifers are present at the site. Ground water
flow is prolific, consisting of a steep valley flow to the north
from the southern part of the City, which is then redirected in a
northwest trend by the Xootenai River alluvial plain, a local and
regional ground water discharge. Ground water is located
relatively close to the site surface, from 8 to :5 feet below
grade (Figure 3 ) .
The Champion mill property is industrial, virh large
buildings and warehouses used in the milling and sawing
processes. Diversion water from Libby Creek recharges several
ponds on site which are used for fire suppression or to float
logs. Residual ash frcm burning is kept in a large pile on the
eastern side of the property. Air emissions are principally the
result of boiler operations and are regulated by State permit.
An MPDES permitted outfall discharges treated effluent to the
Kootenai River on the northern property boundary.
II. Site History and Enforcement Activities
The Libby Ground Water site is located on the Champion
International Corporation lumber and plywood mill in the city cf
Libby, Montana. The Champion mill (hereinafter "facility"' '-.as
been an active forest products processor for a number of years.
The facility was first known as the J. Neils Lumber Company.
Wood treatment operations began in approximately '946 and
continued until '969.1 St. Regis Corporation p rhased the
company in 1957 and continued wood treatment operations. In '985
the facility was purchased by Champion International Corporation,
the current owner. The facility purchase was part of the merger
of St. Regis with Champion, at which time Champion assumed St.
Regis' liabilities.
Wood treating fluids and constituents are known to have been
disposed and spilled at several different locations at the
facility during the early operation of the plant (Figure 4).
Waste water, formed as vapor in the retorts, was placed in waste
pits after treatment by a condenser and oil separator. Sludges
which built up in the bottom of wood treating fluid tanks were
periodically removed and hauled to an uniined waste pit.
Overheating of the butt dip treatment tank fluids created foam-
overs which spilled onto the ground. Spills occurred in tr.e tank
farm area and at the butt dip tank, and also around storage
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tanks. Spills varied rreatly ir. quantity, ar.d success 7:
recovery attempts varied as well, therecy preventing accurate
estimates of the total quantity lost to the environment.-
Four different wood treatment compounds have been identified
as compounds used at the site, in varying amounts. Zreosote, a
substance composed almost entirely cf polynuciear aromatic
hydrocarbon compounds (PAHs), was used throughout the history of
wood treating operations, often with a carrier fluid.
Pentachlorophenol ' Pent-a) use began in the early 1950s and
continued until ' 69. Penta generally was combined with a
carrier oil, such as diesei, in a 19:1 ratio, carrier prevalent.
A salt solution comprised of various inorganic compounds such as
Copper-Chromium-Arsenate iCCA) was used for treating during the
latter 1960s. Occasionally, a mixture of penta, mineral spirits,
polyethylene-giycol, and wax was combined with a 1:1
creosote:fuel-oil nx for treatment.
The existence of a contamination problem at the Libby site
was first investigated by the Montana Department of Health and
Environmental Sciences (MDHES) Water Quality Bureau in April,
1979, when water from a newly drilled residential well was found
to smell of creosote. In September of 1.980, pursuant to CERCLA,
the EPA Field Investigation Team began site investigation
activities. EPA personnel and the Lincoln County Sanitarian met
with St. Regis Corporation representatives at this time to
discuss past wood treatment processes and waste disposal
practices at. its facility. St. Regis submitted a Notification of
Hazardous Waste Site to EPA on June '0, 1981 listing UOSi,
creosote1 as the type of waste.3 Further investigations,
including well water sampling, indicated that ground water in
some locations was contaminated by pentachlorophenoi as well as
creosote compounds. Past waste disposal practices and wood
treatment compound spills at the facility made it a prime suspect
as the source cf ground water contamination.
The Libby site was proposed for inclusion en the National
Contingency Plan list of priority hazardous waste sites in
December, 1982. The site was placed on the first National
Priorities List in September of ''.983, with a Hazardous Ranking
System score of 36.67, making it eligible for remedial response
action under the Comprehensive Environmental Response,
Compensation, and liability Act (CSRCLA).
On October i>, '983 EPA issued an Administrative Order on
Consent (Docket * CERCLA VIII 83-03-) stating that the site
presented a potential threat for release cf hazardous substances
into the ground water. The Order directed St. Regis Corporation
to begin remedial investigations, feasibility studies, and
remedial, action programs. Champion International Corporation
assumed all responsibility for the Order when it acquired and
merged with St. Regis Corporation in January, *?35. N'o lawsuits
-------
have been filed to date against :ha.T.picn Ir.terr.aticr.ai
Corporation or any other potentially responsible party
Libby site to conduct cleanup activities.
Remedial investi-ation and feasibility study activities --ore
begun in '.983 by St. Regis. The objectives of the investigations
were to define the limits and extent of site contamination, and
develop and evaluate available alternatives for minimizing and
mitigating the endangerment posed by the site to human health and
th«'environment. These investigative activities have resulted in
Phases I through IV field investigation reports, reports of
ongoing water sampling programs, laboratory and field tests to
determine most effective site cleanup programs, and feasibility
studies evaluating cleanup alternatives. A complete list of
reports used to determine thet remedies described in this Record
of Decision is included in the administrative record.
A remedial investigation and feasibility study for operable
unit 1 of Phase IV was completed in July 1986. It addressed
public exposure to contaminated ground water. As a result of
this investigation, EPA recommended that an alternate water
source be supplied to residents whose wells were contaminated by
ground water emanating from the facility. This recommendation
was approved in a September 26, 1986 Record of Decision.
Implementation of the remedial action was conducted by Champion
International Corporation, pursuant to the existing
administrative order. Investigative activities since that time
have addressed the remainder of the environmental and public
health threats posed by the site. Documentation of activities
subsequent to the 1986 ROD is included in the Remedial
Investigation Report, April 1988 !and public review draft of the
Feasibility Study for Site Remediation, November '988.
Special Notice for remedial design and remedial action as
described in Section 122 of CERCLA has not yet been provided to
Champion International. EPA anticipates issuing Special Notice
.approximately two weeks subsequent to finalization of this ROD.
Negotiations are predicted to commence shortly thereafter and
culminate in a judicial consent decree for implementation of
remedial design and remedial action, recovery of ail past EPA
expenditures- related to the site, and provision for ongoing
reimbursement of future EPA costs. It is anticipated that the
State of Montana will also participate in the consent decree and
seek reimbursement for past costs. The consent decree should be
formalized no later than 120 days after issuance of Special
Notice, but Champion International, MDHES and EPA have all
expressed a strong desire to conduct the consent process in an
expeditious fashion.
Technical discussions have been conducted between Champion
(the potentially responsible party, or PRP), EPA and MDHES since
site investigative work began in the early 1980s. Accounts of
-------
:-. e e 11 n a s and conversations are contained within the
istrative record. T-f r.cre particular interest i.id app 11 lici 11•y
to this remedy selection are discussions wnicr. have centered en
issues raised during review of' the first -draft of the phase IV
feasibility study report dated February, -?37. EPA and MDHES
submitted detailed comments on this study to Champion in
September, 1987 which identified numerous ma^or deficiencies.
Since that time meetings have been held generally every other
month to try and resolve differences in process, technical
interpretations and remedial alternative evaluation. Summaries
0$ .these meetings have been formalized into memoranda in the
administrative record.
ill Community Relations History
Although community interest in the Libby site has been
relatively low, EPA and MDHES maintained an active community
relations program during RI/FS activities. Fact sheets or
project updates were prepared at various stages to inform Libby
residents of the status of site activities. MDHES and EPA
conducted interviews of local officials and residents in January
1988 to determine the adequacy of the agencies' information
distribution system.
An administrative record has been established for the Libby
site. The record is available near the site in the offices of
the Lincoln County Sanitarian, 418 Main Avenue, Libby, Montana,
and in the docket review room of the U.S. Environmental
Protection Agency's Montana Operations Office, 301 S. Park,
Helena, Montana. Records at both locations may be reviewed
during normal business hours.
In order to assure that interested persons, including
potentially responsible parties, may participate in the
development of the Libby administrative record, the following
actions have been taken:
i. Pursuant to Section ii7(a) of CERCLA, a proposed plan
fwas made available to Libby citizens, legislators,
potentially responsible parties, and other persons. The
plan summarized the RI/FS process, described the response
action alternatives, and provided a brief analysis of the
alternatives preferred by EPA and MDHES. The proposed plan
was mailed to persons on the EPA mailing list, distributed
in the weekly city newspaper, and made available at the
public repository in the County Sanitarian's office.
Notification of the availability of the plan was made via
newspaper notice.
2. Concurrent with distribution of the proposed plan vas
the initiation of a 30-day public comment panod to allcw
-------
persons to pro'-' ie official comment zr\ t.-.e plan and ctner
documents contained in the administrative record.
3. In order to provide another opportunity for public
comment and discussion on the proposed plan and other Libby
site issues as necessary, a public meeting was held on
November 29 at 7:00 p.m. in the Lincoln County Annex
Building in Libby. The date, time and place of this public
meeting was published in the proposed plan as well as two
editions of the local newspaper. Also, public service
announcements were broadcast as news items on the local
radio station.
4. Verbal comments and questions were noted during the
meeting. In all instances, responses were immediately
supplied to the public at the meeting. Written comments
have been accepted for the duration of the public comment
period. A response has been prepared for each of these
comments. The comments, questions and responses are
contained in the Responsiveness Summary attached to this
document.
Subsequent to the selection of remedial response actions
described in this document, through the signing of this document,
EPA will publish the Record of Decision as a final plan.
Included in the final plan is a discussion of any significant
changes, and the reasons for those changes, from the proposed
plan. Included in the final plan will be a response to each of
the significant comments or questions submitted during the public
comment period. Announcement of 'the availability of the final
plan will be made by notice in the Libby newspaper. The final
plan will be made available for review in the public repository,
and for review and copying at the EPA office in Helena, Montana.
A thirty day public comment period will be provided for the final
plan.
The availability of technical assistance grants for citizen
groups was publicly noticed in various Montana newspapers during
the spring of 1988. Further notice was verbally issued in Libby
'during a presentation to the local Rotary group, and to the
Lincoln County Sanitarian, since he is the primary local contact
for persons'interested in the site. Mo grants were requested or
awarded for this action.
IV. Scope and Role of Response Actions
The response actions selected for implementation at the
Libby site are designed to alleviate the primary threats to
public health and the environment, posed by contaminant sources
and contaminant migration, for the soils and upper aquifer. The
response action for the lower aquifer is intended to aid the
-------
Agency in finding a rs.iacle, rest, selective c
response actions ."nay be evaluated in terms c: separate operable
units or sub-actions, they are actually very dependent upon
concurrent implementation. The following paragraphs briefly
describe the three manor sub-actions; soils, upper aquifer and
lower aquifer. A more thorough characterization of the suc-
acticns iknown as^operable units in the F3 report, may be found
in the RI Report. *•
Soils/Source Areas: Soils :~ some areas of the site are
contaminated with wood treat _.ig compounds (Figure 4). These
areas are considered "sources" because they provide an
ongoing source of contaminant loading to the ground water
through precipitation infiltration and leacning. They also
pose a direct contact threat. In order to effectively
address ground water clean up, the source areas must be
cleansed of contaminants or isolated from the hydrogeolcgic
system.
upper Aqua-err The Libby ground water system has been
severely impacted by the uncontrolled migration of wood
treating compounds from the unsaturated zone, or source
areas, into the shallow upper aquifer. The hydrogeologic
system is generally characterized by highly transmissive
deposits which transport a prolific ground water flow from
the site north and northwest toward the City of Libby. The
upper aquifer, located between depths of approximately 15 to
70 feet, is contaminated primarily by dissolved
constituents. The upper aquifer is most commonly used for
drinking water and irrigation wells down gradient, although
there is currently a prohibition against drilling new wells
in the city of libby, and almost all residents located
within the contaminant plumes use city water :or drinking
and irrigation purposes.* In order to allow residential cr
other use of ground water from this system in the forseeable
future an active remediation program must be initiated.
Otherwise, the prohibition against drilling r.ew wells must
be extended until such time as natural attenuation
. ,alleviates the public health and environmental threat.
Lever Aguirer: The lower aquifer is separated from the
upper by a relatively low permeability zone approximately 25
feet thick which generally provides a hydraulic separation
*Some well owners within the historical boundaries of the contam-
inant plumes have refused to stop using well water for certain
functions, usually lawn or garden irrigation. Three wells are
still used by the owners and families as a source of drinking
water. All three of these wells are on the very edges of the
contaminant plume, and the risk is not considered to be high.
However, Champion International continues to attempt to convince
the well owners to accept the buy-water option (September, •?35
-------
ROD) "3 eliminate "his peter,tial exp
between the two systems. The lower aquifer ranges in depth
from approximately '00 to : 50 feet below ground surface.
This system is less -'ell Defined than the upper aquifer but
is thought to exhibit high transmissivities as veil. Wood
treating compounds are fcund in the deep aquifer in a
dissolved state, but the problem is compounded by the
presence of light and dense non-aqueous phase oils which
. , • provide a continuous source of new contaminants to the
system. Because of the excellent hydraulic properties of
the upper aquifer, no residential or irrigation wells are
located in the lower aquifer downgradient of the site.
Therefore, there are three distinct major sub-actions at the
Libby site which may be defined by media. This Record of
Decision details the remedy selection process for th« entire site
as a single response action, but in fact the process used to
select the feasible alternatives was conducted by the media of
concern. A thorough explanation of the rationale for this
approach and the complete analysis may be found in the
Feasibility Study for Site Remediation.4
V. Summary of Site Characteristics
As discussed earlier, wood treating fluids and constituents
are the contaminants of concern at the site. Contaminants are
found in soils and sediments at several different locations
including former waste pits, tank storage areas, and butt dip and
treatment tank sites. The contaminants are the result of dumping
of spent fluids, overflow of treatment tanks, and spills. The
four different wood treating compounds 'used include creosote,
pentachlorophenoi, copper-chromium-arsenate salts, and a mixture
of various compounds including creosote and penta. In addition,
certain carrier fuels or oils were used with the treating
compounds, and these have contributed primarily volatile organic
,contaminants to the environment. The remainder of this section
will discuss first the characteristics of the contaminant
compounds used, and then the extent of contamination in the soils
and upper and lower aquifers.
Contaminant Characterization
Creosote: Creosote is a_complex mixture of organic
compounds produced from coal.^ At least 200 compounds have been
identified in creosote, although it is possible that several
thousand different compounds could be isolated. Most of those
are present in very small amounts. The major components of
creosote are the neutral fraction polynuclear aromatic
hydrocarbons (PAH). Other components include tar acids, such as
phenols and cresols; tar bases, such as pyridenes and acridine;
and the nitrogen containing polycyclic hydrocarbon compounds such
-------
as quir.ciine. Because creosote is a clend c. ccal i i 3 -, 111 at icr.
processes it does not have a definite composition, and pnysicai
properties, such as specific gravity and PAH content, may vary by
manufacturer and/or by application (poles vs. railrcad ties,
etc. ) •
The ?AHs are the primary components of creosote which are of
concern at the Libby site. The ?AHs have variable solubilities
which decrease with increasing molecular weight, from about 34
ppm. for napthalene to <1 ppb for benzo(g,h,i ) -pyrene.4 (This
large difference in solubilities has important implications for
treatment design.) The property of solubility can be used as a
guide for adsorptive behavior. As aqueous solubility decreases,
adsorption increases. Because of the low solubility of some of
the ?AHs, adsorption onto subsurface sediments has been a
dominant process in control of their migration. The solubilities
and adsorptive properties of ?AHs together control the
environmental mobility. It is expected that the lighter, more
soluble compounds will have migrated further than the heavier
compounds which will be adsorbed onto sediments in relatively
greater concentrations. The PAH compounds .are also considered
non-volatile under ambient conditions, but this property varies
considerably with molecular weight, with the heavier compounds
generally less volatile or susceptible to move into the gaseous
state.
. Fentachlorcphenol: The technical grade pentachlorophenol
(penta or PCP) used for treating wood contains 85 to 90% penta.
The remaining materials are 2,3,4,6-tetrachlorophenol, 4 to 3%;
"higher chiorophenols," 2 to 6%; and dioxins O.i%.5 Other
compounds are produced as contaminants during manufacture,
including complex phenols, ethers, chlorinated dibenzofurans and
chlorinated dibenzo-p-dioxins. The principal chicrodioxin and
chlorodibenzofuran contaminants found in penta are those
containing six to eight chlorines (hexa, hepta and ccta ) .5 The
most toxic isomer, 2,3,7,8-tetrachlcrodibenzo-p-dicxin, has not
been detected in any analysis of soil, oil or ground water at the
• site.
"Penta is a mild acid which ionizes in solution to form
pentachlorophenate anion. The ionization is dependent upon pH cf
the environment, and its aqueous solubility may therefore vary
greatly. Penta is volatile enough to be steam distilled, and the
relatively high volatility, compared to other chlorinated organic
compounds of low vapor pressure, can cause losses of oenta from
soils similar to those cf the lightest PAH compounds.*
The dioxins and furans contained in penta display different
physical characteristics. They generally have very low
solubilities, in the part-per-trillion range, and they are more
adsorptive than even the heaviest PAH compound. Vapor pressures
for dioxins and furans are lower than the PAHs as well, and they
-------
are considered non-volatile at ambient conditions. The In-
solubility and high adsorption coefficients help to explain
dioxins and furans have not been encountered in ground water
samples, without.NAPL present, at Libby.
rccper-C.'^rc.'niu.Tt-.A.rs'enate: .-. Copper-Chromium-Arsenate • 3CA )
salts solution was used to treat wood for a relatively short time
during the late 1960s. The salt solution probably also contained
fluoride and dinitrcphenol. A fire retardant was also believed
:to« have been used which contained zinc chloride, chromium, boric
acid and ammonium sulfate. The primary contaminants of concern
from these solutions appear to be zinc and arsenic in some ground
water wells. Nickel and lead have been detected above background
levels as well. (It should be noted that fuels or carrier oils
may also have contributed metals to the soils and ground water.)
0ther Ccmpcunds: Volatile organic compounds such as benzene
and methyiene c-loride have been detected in ground water
samples. These compounds are thought to have derived from the
carrier fuels, :ils or solvents used in the various treating
processes. For instance, diesel fuel, which contains benzene, is
commonly added to penta prior to butt dip operations. The
volatiles are generally very soluble in ground water. For
example, benzene has an aqueous solubility of 1,850 ppm at 25°C,
more than one million times greater than dioxins. The volatiles
are generally not easily adsorbed onto soils because of their
' high solubilities, but they have a much higher volatilization
potential at ambient conditions.
Extent of Contamination
The following paragraphs describe the extent of.
contamination at the site in terms of contaminant concentrations,
locations, migration routes, etc. Detailed analyses of site
characteristics, including the extent of contamination, are
available in documents contained within the administrative
record, including the 1988 RI Report, the March !936 Phase IV RI
Report, and sampling data summaries from all historical site
investigations.
Soils: • Soil contamination at the site varies greatly, .-.ot
only between source areas but also within source areas.
Volatiles such as xylene have been detected, but in relatively
small concentrations. Most of the very volatile compounds have
probably migrated into the ground water or were volatilized
during exposure to atmospheric conditions. Elevated levels of
metals such as zinc and lead have been detected in some sampling
locations but overall the concentrations are not of concern.
(Because of the short time span during which metal salts treating
compounds were used, it is possible, that a discrete substrate
horizon may be encountered during soils remediation which
contains higher concentrations.)
-------
The primary contaminants of concern in tne soils a.-.d
subsurface sediments are the PAHs, penta and to a lesser extent,
dicxins. Table 1 lists a summary of contaminant concentrations
detected in samples from test pits and borings from the waste pit-
area, the tank farm, and the treatment areas. Figure 5 depicts
the sampling locations within the tank farm area, mineral spirits
tank area, retort area, runoff collection ditch, butt dip
treatment area, and waste pit area.
• « • Measured soil PAH values ranged from non-detectable to per
cent concentrations in the waste pit area at one depth. The
waste pit area had the highest PAH soil concentrations of any of
the treatment, storage or waste disposal areas. Measured ?CP
values ranged from non-detectable to over 2,700 ppm in the waste
pit area, which also had the highest overall PCP concentrations
of any of the waste areas. The highest concentrations of dicxins
and furans are from the butt dip tank area (Table 2). The dioxin
homologs most often detected, and in the highest concentrations,
are octa and hepta. Sampling coverage for dioxins and furans at
the site is not extensive. However, the results of the analyses
conducted are consistent with data on dioxins and furans from
other wood treating facilities, in both the homologs found and
the relatively low concentrations.
Overall, soil concentrations have been relatively well
defined in a horizontal scale. Extensive samplings during the
various investigations at the site have defined the limits of
contamination around the known treatment, storage and disposal
areas. Vertical extent of contamination is less well defined,
for two reasons. Wood treating fluids have been migrating
downward through the unsaturated zone and into the sediments of
the upper aquifer. Sampling at depths well below the water taole
indicates the presence of contaminated sediments. The
contaminants have therefore been able to migrate quickly through
the highly porous soils and sediments underlying the waste areas.
The second reason why the vertical extent is less well quantified
, is a problem of definition of the source areas. As described
previously, many of the contaminant compounds adsorb readily onto
solidi matrices. Oils which have migrated with the ground water
in a separate phase may ultimately adhere to sediments well
within the water table and far from the original place of
deposition. In this respect, those adsorbed contaminants are now
a non-aqueous phase source of further aqueous contamination.
This problem helps to explain why the division between soils or
source cleanup and ground water remediation is not exact.
Upper Aquifer: The extent of contamination in the upper
aquifer has been well delimited. The primary contaminants of
concern in the ground water are the PAH compounds and penta.
Certain metals, such as arsenic and zinc, have been detected
above background, but arsenic (above background, below Maximum
1 1
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TABLE 1
CONTAMINANT CONCENTRATIONS AND SOIL SOURCE AREAS DESIGN CRITERIA
OuljP VeluMt (id1] Nonccrxlnoafnu' Uixlnoacnlc*'
foUl HP PArh Ht\i Volclll* Or)«k Ctmgoanii (at/kg
VoliM«l i«ll ftockt (of/It) (*>4/k») ("9/k9> ItniciM lolutit* lfl«n«
y«»U >U *r»> 21 .SOO 11.2)0 4.JIO
•>»tor of S«B»ln J2 II 17 14 14 14
- li«Wr of ScBpItt Akaw* 21 SO SO 0 4 •
tMKtlM
NlnlM* CoHCtnlrcllon 1.0 2.0 .SJt .Oil 0.0*
- Nutra CoxtMrtlto 2700 2644S.O 7184.0 0. II 1060
- twMtlrlc NMm 1S.7I B«I.S 164.4 .024 0.72
Ui* If* 7.440 4.0JO 1.140
«-*.r ^ i^l« 4 27 21 » 4 »
- lM«Mr •/ Itl^lM Afcen t t 1 lit
- H !•!•«• C«MC«ntr«tl«« 4.1 .111 I. M)2 .M . « 1.02
- M«.UM C«ic«Mr*tl«. It 2)2.0 III.O .M . J4 1.14
- «4«Mlrlc NMK« 4.4 10. t 10. 1 . M .M 1.17
•utl Olf Ar*« O'O (40 2)0
A. Cr f»
14 14 14
14 IS IS
2.0 7 4.0
44.0 It 40.0
1.21 »./ 11.44
444
t t 1
4 « i
1* 2* 10.0
10.1 12.42 7.10
0«U
N.I*
NO
I. I
O.I)
i.o y u 12
Al I *. .41
JU.UOO 24.0UO A.UUO
-------
' 4
It
III
ill
r j
I INI fONO
O/'S >
BUTT DIP
TREATMENT
AREA
'
WASTE PITS
AREA
I I i. i li li
i
mail
(MIllllliH llillHVAl
Illllt.
^ - ^' I Idl'j'j 'III lull I lit AI KIN
x rn/'M I'M 'i > i : : IK i no
> ® I'llAM I Illl II N^IOMI II II |ll( Al Hill1,
W I'l... I uNl llflSHWIIIt, AN|i USlMlliH
I (IIMIAHIIlAII 1) Mill llUCKNI'jS
»,'i» S
' IJIII",1, IKIbAllll'AII II Mill lull Mil'/.
IMII'fll II I In Al IIIH I III I Kid II
Ifl Aid A1, Mill I n I All. III CAM AllAMM-j
lil'H AI4Al»MSwtH| HMD. ^ .1X10.IMIII
liri ( HllilllS MAS A'.MiHIO III
HlH |>|»ii I'AH
»,
SOU (>IO() C»-M HAMI
MAP
I i«|IU»f S
-------
TABLE 2
POLYCHLOR1NATED FURANS AND OIOXINS (PPB) IN SELECTED SAMPLES1'2
Soap I•
Nuaber
_
Hast* Wos»e
Pit
Soil5
Seapla
Pit
301)
Soil
HOT
Pit far*
3017
503)
Butt Dip Butt Dip
lank Tank
Soil
5041 Sa«pleJ
Average
Soil
ConcantratIon
Oil
3012-3
6004
Average
OM
ConcantratIon
Furana
tatre
pant*
haxa
hepta
octa
<0.084
0.64
25.0
110.0
130.0
-------
Contaminant Level • MCL ) in Safe Dr in < ir.g Water Act ^ocears to ce
limited to wells close to the source and seme .so.atad off-site
wells near the Champion property line. Certain volatile organic
compounds, such as benzene and methylene chloride, occur in the
ground water, but attempts to predict migration cehavior have
been unsuccessful. For instance, benzene concentrations <5Q ppb
have been measured at several locations within tne PAH plume, but
these are not consistent. Volatile organics may be the result of
source oil presence in the aquifers which continue to contribute
to ground water contamination. Dioxins and furans have not been
'detected in ground water samples which, do not contain a non-
aqueous phase component.
Figures 6, ?, and 3 depict isoconcentrations of
pentachlorophenol, non-carcinogenic PAHs and carcinogenic
(including suspected) PAHs in the upper aquifer. All of the
plumes presented in these figures reflect the area ground water
flow trending north to northwest. Highest concentrations of
contaminants are found immediately below the waste disposal
areas. For PAHs and penta the concentration gradients are quite
steep with higher concentrations near the source. Penta
concentrations decrease rapidly away from the source, and near
the property boundary concentrations are approximately 100 ppb.
PAH concentration plots are similar. Concentrations of PAH
compounds vary from hundreds of parts per million near the waste
pit area to hundreds of parts per billion near the Champion
property boundary. All of the plots show that aqueous phase
contamination in the ground water has migrated some distance from
the source areas. The fact that contaminants have not migrated
further in the ground water, given the system's high
transmissivity and the length of time since contaminants were
probably introduced to the system, is somewhat surprising.
However, diffusion, microbiological decay and contaminant
adsorption onto sediments has probably controlled the lateral
extent of contamination.
Lover Aquifer: There are fewer sampling locations in the
lower aquifer, but dissolved contaminant distribution is believed
to be similar to the upper aquifer. Contaminant plumes extend
off s^ite; in fact, penta concentrations may be even greater in
some of the deep aquifer wells than in the upper aquifer. Weil
6007, which is northwest and outside of the upper aquifer penta
plume, has revealed penta concentrations in excess of 1,100 ppb
on more than one sampling episode.
Definition of the lower aquifer and contamination in the
lower aquifer has been complicated by the presence of non-aqueous
phase wood treating oils in some locations. Wood treating fluids
may be lighter or denser than water and quite viscous. Oils
which have not been adsorbed onto soils or broken down by
bacterial activity have migrated into water bearing formations.
Once into the saturated zone, dense NAPLs continue to respond ~o
1 2
±
t
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-. ' ,v.(7 - :-"~
l,*"*'! 'OLl-- V* '
Nitll II.NHHM V'l Itl ^ AMI IN
.'./I
II Ul IK I llm I 111 I .
ml v«
SuALtOW ONIXJNU \ftAltH
IbUCONCtNTKAIlON
CAHCINOCCNIC
-------
gravitational force a.-.ci move, via capi--ary action, as stri.-.gers
which are limited by encountering finer grained, impermeable
materials. At Libby, these impermeable materials tend to occur
in discontinuous lenses. If the slope of the lens is not
sufficiently steep the oil may stop migrating. Because the
lenses are discontinuous, in a very complicated mixture of
fluvial and glacierluvial constructed hydrcgeology, the locations
of these oils have been unpredictable. The result is that free
phase heavy oils continue to reside in the lower aquifer, acting
as,source materials and continuously providing dissolved
contaminant loading to the ground water.
VI. Summary of Site Risks
A baseline human health endangerment assessment was prepared
in support of the Feasibility Study for the ''st operable unit''
This initial endangerment assessment evaluated only the current
and future risks to persons associated with contaminated around
water in the upper aquifer. The feasibility study report"1 upon
which this Record of Decision is based updates that baseline
endangerment assessment and expands upon it to include a human
health and environmental impact evaluation for all potential
exposure pathways (See Appendix D, December 1988 FS Report). The
results of those evaluations are presented below.
Indicator Compounds
Thirty-five different organic and inorganic compounds have
been detected in private ground water wells near the Libby site
during the course of site investigations. Table 3 lists most of
these compounds and presents the range and geometric mean
concentrations for each compound detected. The geometric mean
concentration was used as the long term concentration to
determine the chronic daily intake for each contaminant. The
compounds listed in the table were subjected to the indicator
chemical selection process as outlined in the Superfund Public
%Health Evaluation Manual7. The procedure utilized evaluates and
'ranks the chemicals in terms of carcinogenic potency and
t.oxic;.ty. Table 4 presents the results of the indicator
selection process along with the respective chronic and/or
subchronic acceptable intake concentrations and the carcinogenic
potency factor (C?F) for those compounds identified .as
carcinogens. Table 5 presents the indicator score values for the
compounds, distinguishing between potential carcinogen and non-
carcinogen values where applicable. Some compounds have been
retained as indicators for reasons other than a procedural
determination. For instance, the compound may be a suspected
carcinogen as are some PAHs or, in the case of pentachlorophenoi,
the compound is ubiquitous throughout contaminated zones.
Mote that the benzol a )pyrene C?F has been used to evaluate
health risks for all known or suspected carcinogenic polyaromatic
-------
TABLE 2
CONTAMINANTS DETECTED IN PRIVATE GROUND-WATER WEILS
Chemical
Arsenic
Z1nc
Copper
Chromium III (3)
Lead
Nickel
Pentach 1 oropheno 1
Naphthalene
Acenaphthylene
Acenaphthene
Fluorene
Phenanthrene
Anthracene
Fluor ant hene
Pyrene
Chrysene
Ben2o(a) anthracene
1-methyl napthalene
2 -methyl napthalene
Benzene
Toluene
Total Xylene
Methylene Chloride
2-Butanone
Ethyl benzene
l,l-
642.60
52.70
3.67
32.40
23.80
52.12
24.06
12.79
23.53
6.97
3.96
0.57
0.27
0.27
0.24
0.09
71.18
32.53
3.28
1.81
16.32
2.53
13.54
2.50
0.55
1.06
6.45
. MO. of
Same les
Above
Detection
2
12
10
5
2
4
23
21
12
20
31
22
16
10
6
4
1
7
7
15
13
20
6
6
10
2
4
2
(1)
Only values measured above detection were used in calculating the
geometric mean.
<2) No geometric mean concentration Is calculated since this compound was
detected 1n only one well during one sampling period (July 1985) and
the concentration detected equals the detection limit.
(3) All Chromium 1s assuned to be trlvalent.
* Compounds detected in NAPL in. aqueous samples are r.ot r.ecessariiy ••'•c'.
Sheet 1 of 1
21990-21523 (21990
-------
TABLE i
CRITICAL TOXICITY FACTORS*
Chemical
Arsenic
Benzo(a)anthracene
Chrysene
Fluoranthene
Pyrene
Benzene
Nickel
Lead
Copper
Zinc
2-Butanone
Ethylbenzene
Toluene
Pentachlorophenol
Chromium III
Xylenes (total)
Methylene chloride
I,l-d1chloroethane
Tetrachloroethylene
l,l,2-Trichloro-2,2,l-
Trlfluoroethane
^cceotable
Intake for
Subchronlc
Exposure
(uq/kq/day)
..
—
--
--
--
--
20
--
37
210
—
970
430
30(T)
14,000
100
—
1,200
--
--
Acceptable
Intake for
Chronic
Exposure
(,q/kq/dav}
..
--
—
--
--
--
10
1.4
37
210
50
100
300
30
1,000
10
60
120
20
30,000
Carcinogenic
Potency Factor'2*
1.5 x 10'2
1.15 x 10-2 3)
1.15 x 10-2 31
1.15 x lO'2 3)
1.15 x 10'2
5.2 x lO'5
--
.-
--
--
..
.-
._
..
--
7.5 x ID"*
._
5.1 x lO'5
--
* All values and factors are taken from the Superfund Public Health Evalu-
ation Manual, October 1986, Exhibits C-4 and C-6. These values are not
adjusted for site specific conditions.
(T) Indicates that the AIS 1s based on teratogenic or fetotoxic effects.
(1) These values are based on quantitative information from toxicological
research. AIS values are based on 10- to 90-day animal studies and AIC
values are based on long-tern animal studies.
(2) The lifetime cancer risk based on a 95-percent confidence limit.
<3) Carcinogenic Potency Factor is based on Benzo(a)pyrene.
Sheet 1 of 1
21990-21525
-------
TABLE =
EVALUATION OF EXPOSURE FACTORS
AND FINAL CHEMICAL SELECTION
Cheialcal
Arsenic
Benzene
Mlckel
Lead
Copper
Z1nc
2-Butanone
Ethyl benzene
Toluene
Tetrachloroethylene
Methylene Chloride
l,l-01chloroe thane
Pentachlorophenol
Chronlun III
Xylenes (total)
Fluoranthene
Pyrene
Chrysene
Benzo(a) anthracene
l,lf2-Tr1chloro-2,2,
Indicator Tentative
Score Value
-------
hydrocarbons in "his study. It should also be pointed cut t.-.at
the geometric mean concentration for 2 , 3,7,3-tetracnlorodibenzo-
p-dioxin (2,3,7,8-TCDD) is used in risk evaluations for soils,
whereas dioxins and furans were not detected in -ground water in
the dissolved state ar.d therefore are not used as ground water
indicator compounds. Finally, no samples collected at libby
detected 2,3,7,8-TCDD. Instead, higher chlorinated, 2,3,7,3-
dibenzo-p-dioxins and dibenzofurans (hexa, hepta and octa)
concentrations, and other dioxin and furan isomers, have been
converted to 2,3,7,3-TCDD using EPA equivalency calculations
(EPA/625-3-87-012).
Toxicity Assessment: The indicator compounds should
represent the most toxic, mobile and/or persistent hazardous
substances associated with the site. T.oxicological research en
animals has provided much of the information with which the risk
evaluations are made. The following summarizes some of the
toxicity effects of the indicator compounds:
o Ingestion of certain indicator compounds has the
potential to cause damage to organs. Benzene, copper
and pentachlorophenol can cause liver and kidney
damage.
o Inhalation of certain indicator compounds may cause
adverse health effects. Many PAH compounds may be
absorbed into the body through the lungs, causing
problems similar to. those resulting from ingestion.
Inhalation of arsenic can cause lung cancer. Most of
the more volatile compounds can irritate the eyes and
upper respiratory tract.
o Dermal absorption of some compounds leads to similar
effects as ingestion. Contact with pentachlorcphenol,
benzene and PAHs may cause dermatitis.
o Many of the indicator compounds, such as arsenic and
benzene, are known or suspected carcinogens. Various
compounds are linked to mutagenic cr reproductive
effects. Some lighter molecular weight PAHs are
considered possible initiators of carcinogenic effects.
Exposure Pathways
Soils and Source Materials: The feasibility study4
evaluated three different potential projected future exposure
scenarios and determined the risks associated with each scenario.
The procedures and assumptions used in this evaluation were taken
from the Superfund Public Health Evaluation Manual, although more
appropriate, specific assumptions were used for given site
circumstances. The following exposure pathways were identifiac
as being of potential concern:
1 4
-------
Residential Scenario: Assumes that at some future date
one or more residences are constructed on the site.
o I ~ c e s 11 c r. of contaminated soils
o Inhalation of contaminated soils
o Dermal absorption of contaminated soils
Industrial Scenario: Assumes that the site will
continue to be used as an industrial facility.
o Inhalation of contaminated soils
o Derma.i absorption of contaminated soils
Construction Worker Scenario: Assumes that new
building construction takes place on site and workers
are exposed to contaminated soils.
o Oral exposure (ingestion) to contaminated soils
o Inhalation of contaminated soils
o Dermal absorption of contaminated soils
Upper Aquifer Ground Water: Exposure pathways for off-site
private wells were developed in support of the 'st operable unit
Record of Decision, which authorized an alternate water supply
for those persons potentially exposed to contaminated ground
water from private wells. Dermal absorption or inhalation of
volatile organics while showering or bathing was evaluated and
found not to be a significant exposure pathway. The following
exposure pathways, also applicable to this study, were identified
as being of potential concern:
o Ingestion of contaminated drinking water
o Child ingestion of soil contaminated by ground water
irr.igat-ion
o Ingestion of home garden produce irrigated with contaminated
ground water
Lover Aquifer Ground Water: There are no known domestic
wells in use which are completed in the lower aquifer in this
area, nor are there likely to be in the near future since the
city of Libby has enacted a prohibition on the installation of
ground water wells within the city limits. However, an analysis
of potential human health impacts associated with contamination
in the lower aquifer was conducted under a conservative, no-
15
-------
action scenario vnereoy a dcrr.estic-use veil vculd cs :.-.sta . 1-sc. it
some time in the future. Dermal absorption cr inhalation c:
volatile organics while showering or bathing was determined to
not be a significant exposure pathway. The following exposure
pathways were identified as being cf potential concern:
o Ingestion cf "contaminated drinking water
o Child ingestion of soil contaminated by ground water
'' . « • irrigation .
o Ingestion of home garden produce irrigated with contaminated
ground water
Risk Characterization: Soils and Source Materials
Potential current human health risks posed by contaminated
soils have been minimized. Clean fill was placed ever the
•contaminated soils during the dismantling of the wood treating
facilities and access to the mill is controlled. Employees
engaged in investigation activities and pilot testing of
remediation alternatives follow safety procedures to reduce the
potential for inhalation, ingestion or dermal absorption of
contaminants.
As noted earlier, three potential projected future exposure
scenarios are considered in evaluating the potential human health
risks posed by a no-action scenario. The results cf these are
described below. Table 6 provides a summary cf the calculated
risks for each scenario.
Residential Scenario: The carcinogenic risks :cr each en-
site area range from approximately 9.6 x 1Q~3 to 3.' x 1Q~4
assuming a maximum exposed individual is exposed to the
calculated geometric mean concentration. The combined area
Carcinogenic risk is calculated to be 3.8 x 10~3. 7-e majority
(>50%) of carcinogenic risk for soils found in the waste pit and
ta.nk farm areas is attributable to suspected carcinogenic PAH
compounds. The carcinogenic risk for soil samples from the butt
dip area is primarily.attributable to the 2,3,7,3-TCDD
equivalency (60%). Hazard indices for each area are -below unity,
indicating no potential non-carcinogenic risk.
Industrial Scenario: The total carcinogenic risks for each
on-site area range from approximately 5.7 x 10~4 for the butt dip
area to 8.2 x 10~- for the tank farm area assuming a maximum
exposed individual is exposed to the calculated geometric mean
concentration. The combined area carcinogenic risk is -calculated
to be 1.75 x 1Q~4. For dermal exposure in the tank farm and
dermal and inhalation exposure in the waste pit area, the
majority of the carcinogenic risk is attributable to suspected
-------
TABLE o
SUMMARY OF HEALTH RISKS FOR EACH LOCATION AND SCENARIO
POTENTIAL CARCINOGENIC RISK
Uaata
SCENARIO Pit
Residential
Industrial
Dermal
Inhalation
Total
Construction
Oral
Dermal
Inhalation
Total
2.82 •
(3.64 N
9.04 *
(1.81 M
9.30 H
(1.66 M
9.97 *
(1.99 «
Worker
2.33 H
2.60 H
2.23 M
2.63 •
•o-4
IO'3)
• 0"6
IO'4)
10"'
IO"5)
• 0"6
IO"4)
io-5
IO"6
io-'
io-»
Yank
farm
4.03 N
(6.10 M
1.66 H
(3.36 N
3.33 M
(6.70 N
2.02 •
(6.20 M
4.21 H
4.62 M
7.90 H
4.79 N
io-»
IO"4)
lO'6
IO"5)
10"'
IO"6)
•o-6
IO"5)
.o-6
.o-'
IO"9
,0"*
Butt
Olp
4.61 M IO"4
(9.62 M 10"')
2.00 * IO"5
(4.00 M IO"4)
6.46 M IO'6
(1.69 M IO"4)
2.84 N IO"5
(5.68 M IO"4)
4.94 M IO"5
5.53 • IO"4
2.00 M IO"7
3.31 H IO"4
All
Areas
1.92 M IO"4
(3.64 N IO"5)
7.97 N IO"6
(1.59 M IO"4)
7.80 M IO"7
(1.56 H I0"5)
8.75 M IO"6
(1.75 H IO"4)
1.95 M IO"5
2.20 M IO'6
1.84 H IO"7
2.19 H »0"5
Maata
Pit
7.72 M IO"4
(1.54 M IO'2)
3.21 M I0~5
(6.42 H IO"4)
1.89 H IO"5
(3.76 M IO'4)
5.10 H IO"5
(1.02 M IO'3)
1.4) M IO"2
1.61 N IO'J
7.28 M IO"5
1.60 H IO'2
NONCARCINOOENIC HAZARD INDICES
Tank
Farm
4.64 » IO'4
(9.26 M IO"2)
1.92 H IO"5
(3.84 H IO"4)
1.42 H IO"5
(2.84 M I0~4)
3.34 M IO"5
(6.68 M I0~4)
7.4) N IO"3
8.30 H IO"4
8.16 H I0~5
6.34 H IO'3
Butt
Olp
1.38 • 10" J
(2.76 » IO"2)
5.81 M IO"5
(1.16 H IO"3)
1.63 « IO"5
(3.66 M IO"4)
7.64 • IO"5
(1.53 H IO"5)
6.61 » \Q~2
7.63 * IO"3
3.76 « 10 '
7.38 • IO"2
All
Area*
6.60 M
(1.36 *
2.66 *
(3.72 «
1.73 »
(3.30 M
4.61 «
(9.22 «
1 .26 .
1.42 .
7.40 .
1.41 >
.o-4
IO'2)
.o"5
.o-4,
IO"5
I0"4»
.o-5
IO"4)
IO'2
,0"3
.o-5
IO"2
Not* i Valu«» In par«nth«aaa Indicate the rlah eat(mated lor the Ma Minn* imposed Individual
-------
carcinogenic PAH compounds. The carcinogenic ris< :or soil
samples from the butt dip area is primarily attributable to the
2,3,7,8-TCDD equivalency (60%, one sample). For inhalation
exposure to tank farm soils 69% of the carcinogenic risk is
attributable to arsenic. The higher arsenic inhalation risk for
the tank farm is due to slightly higher arsenic concentrations in
tank farm soils and a greater potency factor for arsenic
inhalation compared to PAH compound inhalation. However, the
risk due to inhalation exposure overall is small, 3.35 x 1Q'7.
Hazard indices for each area are below unity, indicating no
potential non-carcinogenic risk.
Construction Worker Scenario: Total carcinogenic risks for
each on-site area range from approximately 5.5 x 1Q~4 to 4.8 x
i 0~6 assuming a maximum exposed individual. The_combined area
carcinogenic risk is calculated to be 2.19 x iQ"-. For oral,
dermal and inhalation exposure in the waste pit area, and oral
and dermal exposure in the tank farm area, the majority of the
risk stems from carcinogenic PAH compounds. Risk due to
ingestion of butt dip soils is associated primarily with 2,3,7,3-
TCDD equivalency (76%, one sample). Dermal exposure risk in the
butt dip area is also primarily a result of 2,3,7,8-TCDD
equivalency, again based on one sample. Seventy five percent of
the risk associated with inhalation exposure in the tank farm
area soils is due to arsenic exposure. Finally, hazard indices
for each area as well as total hazard indices are below unity,
indicating no potential non-carcinogenic risk.
It should be noted that the risks due to ingestion and
dermal exposure of soils from the butt dip area have been driver.
primarily by the 2,3,7,8-TCDD equivalency concentration of one
sample. Other samples collected at the Libby site have contained
dioxins and furans, but in typically lesser concentrations than
the butt dip area. More samples have recently been collected
from the butt dip and waste pit areas for dioxin/furan analyses;
results are consistent with the data used in the risk assessment
evaluations.
»
Environmental Risks: Soils and Source Areas
Source c.ontrois already in place at the site effectively
reduce the environmental risks associated with ccnta.mir.ated
soils. Water and sediment samples taken in ponds on .site and in
the surrounding creeks and rivers do not indicate the presence of
contamination. A continued environmental threat is the potential
for further leaching of contaminants from source areas into the
area ground water.
Risk Characterization: Ground Water, Upper Aquifer
A summary of the carcinogenic and noncarcincgenic risks ::r
all private, off-site wells associated with the three d;
-------
TABLE 7
SUMMARY OF HAZARD INDICES AND CARCINOGENIC RISK
FOR OFF-SITE PRIVATE WELLS
UPPER AQUIFER - BASELINE PUBLIC HEALTH EVALUATION
Ground-water Ingest Ion
Ingest Ion of soil
Total
Subchronlc
Hazard
Index*1*
0.5533
—
Total Subchrontc
Hazard Index for
Fetotoxlc Effects
3.1
__
Total Chronic
Hazard Index'"
0.9797
—
Total
Carcinogenic
Risk
3.0 x 10"4
1.3 x 10-4<2>
by children
Ingestlon of vegetables
Irrigated with contaminated
ground water
3.7 x 10-' to
*
3.1 x 10-*
Risk analysis does not apply to this exposure scenario.
(l> A hazard Index value of greater than 1.0 Indicates a potential human health hazard.
(2> Risk attributed to suspected carcinogenic PAH compounds.
(J) Risk attributed to benzene, methylene chloride, and suspected carcinogenic PAH compounds.
Sheet 1 of 1
^ I Wo /1525 (2l99Or-JI4 II 04 CO)
-------
ground water exposure pathways is presented in Table 7. Th<
greatest carcinogenic risks are posed by potential exposure
the suspected carcinogenic PAH compounds by drinking of ground
water (3.0 x IQ"*11 and ir.gestion of soils irrigated with ground
water M.3 x ' j~"* ' . A range cf risks is provided, for the
ingestion cf garden vegetables irrigated 'with contaminated ground
water (3.1 x 10~^ to 3.7 x :.Q"7). Total carcinogenic risk
associated with cumulative exposure under this scenario is
estimated to be 4.3 x !0~4.
Chronic and subchrcnic (short term exposure) hazard indices
have been determined by comparing the acceptable concentration of
a compound which produces toxic effects to the actual
concentration an individual may be exposed to. If a hazard index
value (actual intake concentration divided by the acceptable
value) exceeds one, a potential health risk may be assumed. The
subchronic hazard index for fetotoxic effects resulting from
penta exposure is 3.', indicating a potential health risk. The
total chronic hazard index is extremely close to one.
Two other risk evaluations were performed, one for receptors
for the group of wells located within the current plume of
contamination, and another addressing receptors for only the four
individual wells within the current plume of contamination and
owned by persons not currently connected to the city water
system. The potential risks associated with these two
evaluations are less than the risks calculated for all off-site
wells because cf the assumptions used in modeling. Calculations
used for all off-site wells are based on potential concentrations
in the.future, whereas concentrations used to determine risks for
the latter two evaluations are based on mean concentrations
within the plume and for the four veils, respectively. (See
Table 8)
A no-action human health evaluation was conducted using data
for the four wells within the contaminant plume, currently not
jusing municipal water for irrigation, and potentially using well
'water for consumption. (At present, only one private well is
known ,to use contaminated ground water for consumption, despite
repeated attempts to convince the owner not to do so. The well
is located very near the low concentration edge of the upper
aquifer plume.) Concentrations used in determining the risks
were based on present concentration, and projected for 10 year
and 30 year conditions. Table 9 presents the present and future
risk's posed by ingestion of contaminated ground water at these
four locations. Risks were calculated assuming a 70-kg adult
drinks 2 liters of water a day for a lifetime carcinogenic
potency factor .of 0.0115 (ug/kg/day)-1. Present risk is as high
as 3.24 x .10~4 and the value increases in the future as plume
concentrations in the vicinity of the wells get higher.
-------
TABLES
SUMMARY OF HAZARD INDICES AND CARCINOGENIC RISK
FOR THE CONTAMINANT PLUMES
UPPER AQUIFER - BASELINE PUBLIC HEALTH EVALUATION
Total
Subchrontc
Hazard
Index1 '»
Total Subchronlc
Hazard Index for
Fetotoxlc Effects
Total Chronic
Hazard Index1 '»
Total
Carcinogenic
Risk
Ground-water Ingestlon
Ingest Ion of soil
by children
Ingestlon of vegetables
Irrigated with contaminated
ground water
3.1
0.0201
5.58 x 10-»
2.34 x 10'3
O)
(2)
6.80 x 10'8mto
5.62 x 10'1
Risk analysis does not apply to this exposure scenario.
(l) A hazard Index value of greater than 1.0 Indicates a potential human health hazard.
(2> Risk attributed to suspected carcinogenic PAH compounds.
O) Risk attributed to benzene, methylene chloride, and suspected carcinogenic PAH compounds.
Sheet 1 of 1
(2l»90r-il»
04-tttt)
-------
TA3LE 9 -
ESTIMATED GROUND WATER CARCINOGENIC RISK
FOR THE FUTURE - KO ACTION SCENARIO
(Assuming Ingestlon of Ground Water)
Carcinogenic Risk
HO. Present 10-year 30-year
1023 2.71 x lO'7 2.64 x 1
-------
Risk Characterization: Grcur.d Xater, Lever Aguir'er
There are no" complete exposure pathways for the lower
aquifer since there are no known domestic wells which are
completed in this horizon. A human health risk evaluation vas
therefore performed for only one scenario which assumes a
domestic-use well is installed in this aquifer at some time in
_ the future. Exposure pathways are the same as those for the
' .upper aquifer.
Table 10 presents the carcinogenic risks and hazard indices
for the no-action exposure scenario. Carcinogenic risks are
slightly higher than those for the upper aquifer (total 4.99 :<
TO"4) because contaminant concentrations are estimated to be
higher than those calculated' in the baseline, upper aquifer
evaluation. Once again, the subchrcnic hazard" index for
fetotoxic effects related to oentachiorophenol exposure =xc=>«ds
unity.
Environmental Risxs: Ground tfacer, Upper and Lover Aquifers
Environmental risks posed by contamination in the ground
waters of both aquifers are associated with continued degradation
of the aquifers and potential discharge of contaminant plumes to
surface waters of the Kootenai River and Flower Creek. Risk
evaluations are based on continued migration of olumes.
Both aquifers are contaminated with a variety of compounds,
some lighter than water and some more dense. The*contamination
of the aquifers can be represented by plumes defined by y«ars c*
ground water sampling and analysis. These plumes appear -o'ce
migrating very slowly and may have reached a near steady state.
However, further plume migration presents further ootentiai
environmental risk, as incremental portions of the'aquifers ar<=
damaged. Continued degradation of the aquifers is considered*an
environmental risk. It is worth noting that Montana non-
degradation policies in ground water are based on this approach.
«
A more recognizeable risk is posed by continued olume
migration until ground waters discharge into dcwngradient surface
waters. No detectable concentrations of contaminants have'ceen"^
measured in either water or sediment samples taken from the
Kootenai and Flower Creek, suggesting there have been no
environmental impacts to date.
A statistical model was used to evaluate the potential for
contaminant discharge to both surface systems, using a plume
migration rate based on historical travel distance. Without
remedial correction, the northwest-trending ground water olune
(Figure 9) is estimated to reach Flower Creek in approximately -;
years. The north-trending plume is estimated to reach the
• 9
-------
TABLE 10
NO ACTION PUBLIC HEALTH EVALUATION SUMMARY OF
HAZARD INDICES AND CARCINOGENIC RISKS FOR LOWER AQUIFER
Total Subchronlc
Total Subchronlc Hazard Index for
Hazard Index1 (> Fetotoxlc Substances
Total Chronic
Hazard Index*'»
children
Ingest Ion of vegetables
Irrigated with contaminated
ground water
Total
0.148
76.7
0.556
Total
Carcinogenic
Risk
Ground water Ingest Ion
Ingest Ion of soil by
0.148
76.7
0.556
3.29 x 10-4°}
1.67 x 10-4'"
3.00 x 10-* (
to 3.59 x 10-'
4.99 x 10~4 to
4.96 x HT4
Risk analysis does not apply to this exposure scenario
(l) A hazard Index value of
a potential human health hazard
<2> Risk attributed to suspected carcinogenic PAH compounds (benzo(a) anthracene, pyrene. chrysene.
fluoranthene)
<3) Risk attributed to benzene, methylene chloride, tetrachloroethylene. and suspected carcinogenic
PAH compounds
Sheet 1 of 1
/ •> i itm\r s J I (I
I I
-------
CHAMPION
l^f^ERNAT^ONAL
MILL SITE
UPPCT AOUIFER
CONTAMINANT PLUME
LOWER AOUIFER
CONTAMINANT PLUME
LOWER AOUIFER FREE
PRODUCT HEAVY OIL POOLS AflEA
("Viand* W&r Caulsmi^ati ftuata
-------
Kootenai River in approximately 25 years. Dther more mccila
contaminants, such as penta, may reach these water systems in
fewer years, if remedial action is not taken and contaminants
migrate.
Piezcmetric data for the shallow aquifer indicate that
Flower Creek may not be recharged by ground water flow from the
east in the Liboy area. Ground water gradients near the creek
trend to the north, suggesting there is not recharge to the
smf-ace except possibly near the creek confluence with the
Ko'otenai River. Therefore, no significant environmental impact
is estimated for Flower Creek under a no-action scenario.
A numerical model was used to estimate a discharge of 22.51
million gallons per day from the upper aquifer into the Kootenai
River. The same volume was used for the lower aquifer which has
generally lower productivity, thus creating a conservative
assumption. Projected contaminant concentrations for the
Xootenai River are estimated using maximum and geometric mean
concentrations for each aquifer. Compounds evaluated are
indicator chemicals. Table n shows the resulting Kootenai River
concentration estimates. Comparison of these concentrations with
available Water Quality Criteria for Protection of Aquatic Life
indicates that values are below existing acute and chronic
toxicity numbers, but organic concentrations are obviously above
the existing non-degradation water quality criteria.
Evaluation of. the potential for oil (product) migration into
the Kootenai River,was also conducted. Further movement of oil
pools is considered unlikely because much of the oil is thought
to be captured in \grna11 traps of lesser permeable materials and
sediment barriers/- Additionally, continued migration of the oils
may have resulted Sin such depletion of pooled masses that
critical quantities for movement may not be present.
/'""
However, an estimate of the impact of oil migration based en
tworst-case assumptions was conducted. Using a 2-year minimum
'flow for the Koote;nai River, it is calculated that product would
have t;o enter the -river at a rate of i3 gal/day in order for
penta or suspectedi: carcinogenic compounds (as well as dibenzo-?-
dioxins and/or fur-ans) to be detectable at 0.5 parts per billion.
Although this is a/h unlikely scenario, the uncertainties in the
assumptions used for prediction would indicate that monitoring of
plume movement is .essential.
VI Documentation of Significant Changes
Preferred Alternative - The following alternatives were
.dentified in the proposed plan as the remedies EPA and MDHES
preferred to be implemented at the Libby site:
o Soils and Source Areas - Alternative 5A2': Excavation of
20
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TABLE r.
ESTIMATED CONTAMINANT CONCENTRATIONS IN THE KOOTEMAI RIVER
FOLLOWING GROUND WATER RECHARGE FROM THE UPPER AHO
LOWER AQUIFERS AT LIB8Y, MONTANA
Using Upper
Aqui »er
Conpound (ug/l)
3«n
-------
contaminated 321 Is frcm t.-.e butt iip and tar. x fir.-.
areas and placement in the waste pit area. Initial
phase of bicdegradation treatment. Transfer of soils
lifts to the land treatment unit for final treatment
and disposition. Capping cf land treatment
o Upper Aquifer - Alternative 53: Extraction of product
saturated zone near the waste pit area. .Separation of
oil phase, treatment of ground water in a fixed bed
bioreaction unit, and reinjecticn of treated water to
assist in contaminant reduction in the waste pit area
saturated zone. Installation of injection wells in two
regions to add nutrients and oxygen to the aquifer
system, thereby stimulating biologic activity to
metabolize ''destroy) contaminants in-situ.
o Lower Aquifer - Alternative 5C: Implementation cf a
bioremediation pilot test system to evaluate the
effectiveness of this technology, in conjunction with
oil recovery techniques, in a region with heavy ground
water contamination by dissolved and non-aqueous phase
constituents. Pilot testing is projected to require
two years, although no time limit will be imposed in
order not to constrict the completeness of the
evaluation. Subsequent to pilot testing EPA will
determine the feasibility of implementing a full-scale
aquifer remediation system. Should the technologies
not prove effective, the selected remedy will consist
of monitoring and institutional controls,•with remedy
review at 5 year intervals.- •
Description of Significant Changes: EPA proposed that final
treatment and disposition cf contaminated soils would be in an
unlined cell, in accordance with alternative 5A2. This
alternative was selected based on a belief that contaminants in.
the land treatment demonstration unit would not migrate downward
through the treatment zone. Field data from the land treatment
demonstration unit, received during the public comment period,
indicates that some downward migration of pentachiorophenoi
occurred during treatment. Although the concentrations of penta
detected at .various depths below the surface treatment zone are
well below the cleanup levels prescribed later in t.his ROD, the
presence of this compound demonstrates a potential for migration
during remedial action.
EPA has therefore determined that the land treatment and
disposal unit constructed for clean up of soils and source areas
will require a bottom liner system. The soils and source areas
response action is therefore based on alternative 5A1. The liner
system will provide a low permeability barrier to leachate
migration, and potentially a contaminant sorpant as well.
Although alternative 5A1 used a specific barrier system design
21
-------
for eng i ~ eer ing ar.c cos" ar. a lysis, :..~. al "ie ter mi - at i en of li.-.d
treatment unit configuration will be made during remedial design.
This change is not a rr.aior change, and it dees not require EPA to
obtain public comment on a proposed plan reflecting this change.
e Section n7(b) -zi CIRCLA).
Another item worth mentioning is the decision to make an
interim remedy selection for the lower aquifer response action.
Although no mention was made of this issue in the proposed plan,
EPA .had anticipated selecting Alternative 5C as a final remedy,
pending successful pilot testing. However, due to the
uncertainties of the technologies which will be used to evaluate
remediation of the lower aquifer, the Agency believes that a
final remedy determination should not be made at this time. The
significance of this decision is that a final remedy will be
selected in a subsequent Record of Decision. In all other ways,
the alternative will be carried out as proposed.
Vlfl. Description of Alternatives
A brief but comprehensive description of each of the
remedial action alternatives considered during detailed
evaluation for each of the three sub-actions will be presented.
A more thorough description and discussion of the alternatives is
presented in Chapters 6, 7 and 8 of the Feasibility Study Report
for Site Remediation, 1988. Codes used in these descriptions
(4A, 3B, etc) are consistent with those presented in the FS
Report.- Caution is given that capital, operation and maintenance
(0 & M), and present worth costs, as well as timelines for
remedial action implementation and completion, are necessarily
estimates which may be revised as further remedial design is
conducted.
Sub- Action A - Sofls/ Source Areas
Table 12 lists the remedial alternatives considered for
soils and source area remediation, and classifies those
'alternatives as non-treatment, source control/containment,
treatment, or innovative treatment alternatives. Table 13
presents a summary of the capital, 0 & M and present worth costs
for each contaminated soils remedial alternative. Where
implementation requirements are the same for more than one
alternative, discussion will be presented, once and referenced
thereafter. Also, the description of applicable or relevant and
appropriate requirements is limited to those which are considered
major and/or unique to a certain alternative. For instance, all
excavation alternatives will have applicable requirements
concerning worker safety (OSHA) and RCRA closure. However, these
are not discussed in detail for each excavation alternative. A
more comprehensive list of ARARs is available in Appendix K of
the Feasibility Study Report, and discussion of particular ARARs
for each alternative is contained in Chapters 6 and 8 of that
-------
. TABLE :r
REMEDIAL ALTERNATIVES FOR SOIL: OPERABLE U
Nontreatment
Source Control/Containment
Treatments
Innovative Treatment
1A Mo Action
2A Institutional Controls
3A Capping of Contaminated Soils
4A Excavation and On-Site Landfill
5A Excavation of Soils and On-Site Land
Treatment
6A Excavation of Soils, On-Site
Incineration and Land Disposal
7A Excavation of Soils, Soil/Slurry
Bloreactor Treatment and On-Site Land
Disposal
21990-21525 <21990r«T1 09-01-«) (O«>
Sheet 1 of I
-------
TABLE 13
COST SUMMARY FOR REMEDIATION OF CONTAMINATED SOILS
Alternative
1A -
2A -
3A -
5A -
6A -
7A -
NO ACTION
INSTITUTIONAL CONTROLS
CAPPING IN PLACE
LAND TREATMENT
5A-1 With liner
5A-2 Without liner
INCINERATION
SOIL/SLURRY BIORE ACTOR
Annual
Operation and
Capital Maintenance
Cost (S) Cost ($)
Yr 1 Yr 6L- Yr 2-52
_ w -. / — — —
3.400
1.814.000
1.019.200 1.335.800 189.000
106.800 783.500 248.000
8.170.000
4.828.900
Yr 2-30*
—
2.500
36.000
23.000
23.000
24.000
23.000
Present
Value
Cost (S)
39.300
2.252.500
2.862.600
1.780.800
7.947.300
4.933.500
Unit4
Cost
(t/yd1)
1
75
95
60
265
164
1 Closure
3 LTU operations
5 Monitoring operations
4 30.000 yd* basis
2 1 WO ;
(2l»90r-9H
Sheet 1 of 1
-------
report.
Alternative 'A - Mo Action: This alternative assumes no acticn
will betakento containor treat contaminated soils at the site.
Because contaminated soils contribute to ground vater
contamination a no-action alternative will present significant
long-term health risics. Short and long-term health risks are
presented through exposure scenarios involving land development
and/or industrial activity and/or construction activity.
Leaching of contaminants into the underlying ground water systems
will continue to present an environmental threat. Costs required
to implement and maintain this alternative are zero. Mo ARARs
are met by this alternative.
Alternative 2A - Institutional Controls: Institutional controls
applicable to soils contamination consist of deed restrictions en
land use as well as maintenance of existing site access
restrictions. Land deed restrictions would limit the potential
future uses in 'the event of a sale. Institutional controls
assume no acticn will be taken to contain or treat contaminated
soils at the site. Institutional controls are not fully
protective of human health if implemented alone due to the
continued ground water pathway exposure and uncertainty
associated with deed restrictions maintenance. Short and long-
term health risks are presented through exposure scenarios
involving on-site industrial activity and/or construction
activity, unless limitations could be placed on use by present or
future site owners. Leaching of contaminants into the underlying
ground water systems will continue to present an environmental
threat if this alternative is implemented alone. Mo ARARs are
met by this .alternative.
Costs required to implement this alternative are
approximately S3,400 in capital expenditure; 52,500 per year in
annual 0 & M; and 539,300 in present worth cost. Although
evaluated as a stand-alone remedial alternative, institutional
'controls are also an integral part of many of the remaining
alternatives considered.
. •
Alternative 3A - In-Place Capping of Contaminated Soils:
Protective caps, considered an on-site waste containment
alternative, could be constructed over areas of highly
contaminated soils in the waste pit area, tank farm area and butt
dip tank area. Areas covered by the caps would be approximately
.135,000 ft2 at the waste pit area, 77,300 ft2 at the"tank farm
area and 12,300 ft2 at the butt dip tank area. Areas to be
capped would be. cleared of any existing structures and/or
vegetation and graded to meet slope requirements. Monitoring
wells would be installed both upgradient and dcwngradient of tr.e
capped areas. Caps.would be designed to: (1) provide long-carm
minimization of migration of liquids through the cap, (2)
function with minimum maintenance, (3) promote drainage and
'23
-------
minimize cover abrasion or erosion, (4) acccmodate settling ir.d
subsidence, and (5) have a permeability less than or equal to the
permeability of any bottom liner system or natural subsoils
present. Cap construction could be completed in less than one
year, and monitoring would continue for 30 years.
Caps would provide short-term protection of human health,
but long-term (>30 years) protection is less certain, due to the
'potential for failure or destruction of the physical integrity
a'nd possible halting of monitoring. Environmental impacts are
lessened (relative to no-action) because of the reduction in
fluid migration through the source materials and resultant
reduction in contaminant leaching into the ground water.
Capital cost to implement this alternative is estimated to
be 31,814,000. Annual 0 & M costs are $36,000, while the present
worth cost is 52,252,500.
Relevant and appropriate requirements for this alternative
include certain portions of the RCRA Closure and Post Closure
care .for a surface impoundment. Post closure care restricts the
use of the property as necessary to prevent damage to the cover,
a form of institutional control. Land disposal restrictions
would not be ARAR for this alternative because waste materials
will not be removed from existing locations and placement would
not occur. ARARs for this alternative would generally be met.
CERCLA's preference for remedies which use treatment to reduce
contaminant mobility, toxicity or volume would not be met.
Alternative. 5A(2) - Excavation and Land Treatment, Without Liner:
Contaminated soils from all waste areas would be excavated
and treated in the waste pit area using enhanced biodegradation
techniques to reduce contaminant concentrations. The volume of
soils that require excavation and treatment is estimated to be
30,000 yd3. Excavated soils from all locations would be treated
in the waste pit area until contaminant concentrations have been
reduced 50% to 80%. The butt dip and tank farm areas would be
backfilled after excavation, and relevant and appropriate RCRA
closure requirements would be met for these areas. All soils
targeted for treatment would be screened to remove rocks and
debris. After all contaminated soils are transferred, the waste
pit would be closed in accordance with relevant and appropriate
RCRA requirements. Prior to or concurrent with this activity the
second step treatment cell or unit would be constructed. This
land treatment unit (LTU) would consist of an unlined cell
approximately 3.5 acres in size surrounded by a berm designed to
divert run-on away from the unit and to contain runoff.
Contaminated soils from the waste pit, applied to the unit in
stages., would be tilled to a depth of 12 inches, corresponding .to
the zone of incorporation. The treatment zone would extend to
approximately 5 feet below the initial ground surface. Since
24
-------
ground water is at a depth of 15 feet, the base of the treatment
zone would be more than i meter above ground water as required by
RCRA land treatment regulation (40 CFR 254 . 271(cH2) ) .
Monitoring cf the unsaturated zone within the land treatment
unit would be conducted to determine whether contaminants are
migrating through the treatment zone. Lysimeters would be
installed at the base of the treatment zone to collect soil pore
.liquid and soil cores would be collected within the treatment
zone. Monitoring wells would be installed upgradient and
downgradient of the LTU to monitor ground water. The LTU would
be operated in accordance with RCRA regulations.
The LTU would be closed by capping when treatment is
complete (see later section on cleanup criteria). Although
treatment would be conducted to achieve acceptable contaminant
concentrations, determined using health based risJc calculations,
capping is required because some level of contamination will
remain in the LTU. The cap system would consist of (from the
base upward) (i ) a 24-inch thick compacted clay layer, (2) a
geotextile filter fabric, and (3) a 3-inch thick gravel layer
with an asphalt tack coat. Closure and post closure care would
be done in accordance with RCRA requirements.
Biodegradation of organic wood treating wastes in a soils
matrix has been proven effective at other hazardous waste
locations throughout the country. Successful land treatment was
demonstrated at the 3rainerd Superfund wood preserving site in
Minnesota8 and a successful demonstration of PAH degradation was
conducted for the Paradise Land Treatment facility in
northwestern Montana^. Bench scale laboratory studies conducted
on wastes from the Libby site indicate land treatment is a viable
approach for reducing especially PAH waste components (See
Appendix N, Libby FS Report,, 1988). Results of field
demonstrations performed on Libby wastes using innovative
(enhanced biomass) land treatment techniques during the summer of
1988 suggest appreciable and relatively rapid degradation of
Penta and PAH components (See appendix 0, Libby FS Report, i938 ) .
. i
It is believed that land treatment biodegradation processes
would not reduce the low levels of chlorinated dibenzo-p-dioxins
and dibenzofurans found in some areas of soil contamination. The
low permeability cap installed as part of the LTU closure would
prevent human or environmental exposure to these compounds,
although, as discussed in alternative 3A, caps are not considered
protective in the long .term because of the potential for failure
or destruction.
Long-term monitoring and maintenance requirements would need
to be established for this remedy. Short term exposure risks may
be created; for instance, handling and processing of contaminated
materials increases the potential for exposure. Precautions
25
-------
would need to be taken to prevent worker exposure to
contamination during excavation and during land treatment as
well, since volatilization of some compounds will occur. Proper
design, engineering controls and worker protection can
effectively reduce potential risks.
This alternative would be expected to take 4 to 6 years to
complete treatment and achieve LTU closure. Capital cost to
implement this alternative is estimated to be $390,300. Annual
6- 4 'M costs are $248,600 for each year of active land treatment
(e'st. 5 years) and $23,000 per year thereafter. Present worth
cost is $1,780,800.
The major applicable or relevant and appropriate
requirements (ARARs) for this alternative are as follows. A land
treatment unit must be designed and operated to meet the RCRA
land treatment technology requirements, 40 CFR 264 Subpart M.
Relevant and appropriate or applicable requirements of RCRA 40
CFR 264 Subparts G, K, L, and N must be followed to close the
butt dip, tank farm and waste pit areas, and to cap and close the
LTU. Because land treatment is considered land disposal, land
disposal restrictions are ARAR for the LTU, assuming that 3DAT
concentrations cannot be met prior to placement by August 8,
1990. In addition, based on field tests, one compound may remain
at concentrations above the BOAT levels, even after active
treatment is halted. Should placement of wastes in the LTU at
concentrations above BOAT levels appear to be the most likely
situation, a demonstration of no-migration from the LTU will
provide ARAR compliance. 3DAT numbers which are achievable are
relevant and appropriate end of treatment numbers for this
cleanup.
Alternative 5A( ?) - Excavation and Land Treatment, vith Liner:
This alternative is a variation on 5A(2) which requires
final treatment and disposal of materials in a lined LTU. The
.following discussion will therefore only cover those portions of
the alternative which differ from that presented above.
. i
The LTU design would consist of a lined area approximately
3.5 acres in size. The lining system would be used to stop
migration of leachate from, the LTU. One possible design of a
liner system, evaluated in the FS report, would consist, from the
base upward, of (1) an 18-inch thick compacted clay liner, (2) a
60-mil. thick high-density polyethylene (HOPE) geomembrane, (3) a
12-inch thick drainage sand layer, (4) a geotextile filter
fabric, and (5) an 18-inch thick clean fill layer protecting the
liner system from damage during operation of the LTU. This
composite liner would provide a barrier to the downward migration
of liquids from the LTU. The sand layer would drain any liquids
leaching through the soils overlying the liner. Liquids would be
collected in a leachate collection sump and removed, stored in
26
-------
above-ground storage tanks and recycled in the LTU by irrigation.
Leachate collected would be sampled periodically for
contamination. Monitoring wells would be installed upgradient
and downgradient of the LTU to monitor ground water.
The LTU would be closed by capping when treatment is
complete (see later section on cleanup criteria). The cap system
for this1 alternative would be different from that of the unlined
LTU system because a lower permeability is needed to reduce the
potential for water to collect in the bottom of the cell. The
cap system would consist, from the base upward, of ( 1 ) a 24-inch
thick compacted clay layer, (2) a 60-mil. thick HOPE geomembrane,
(3) a geotextile fabric protecting the geomembrane, (4) a 12-inch
thick drainage sand layer, (5) a geotextile filter fabric, and
(6) a 3-inch thick gravel layer with an asphalt tack coat.
Difficulties inherent in this alternative are similar to
alternative 5(A)2.
Capital cost to implement this alternative is estimated to
be $2,335,000. Annual 0 & M costs are $189,000 for each year of
active land treatment (est. 5 years) and $23,000 per year
thereafter. Present worth cost is $2,862,600.
Applicable or relevant and appropriate requirements for
alternative 5(A)2 will be the same as for land treatment without
a liner. ARARs for this alternative would be met.
Alternative 6A - Excavation of Contaminated Soils, On-Site
Incineration and Landfillinq: \
Contaminated soils from the tank farm and butt dip areas
would be excavated and placed into a bermed containment zone in
the area of the waste pit until the mobile incinerator is
operational. Excavation areas would be backfilled and closed. A
landfill would be constructed south of the waste pit.
Contaminated soils would be screened to remove debris and rocks
•which, after washing to remove the majority of contamination,
would be placed in the landfill. Contaminated soils would be fed
into a fluidized bed incinerator at a rate of approximately
11,000 Ibs/hr. Soils would be incinerated to approximately 85%
of their original mass after organic components have been
oxidized. Treated soils would be placed in the landfill, which
would be designed for solid residues from a hazardous waste
incinerator.
Treatment by fluidized bed incineration is a proven
technology for sludges and liquid wastes and has been
demonstrated for treatments of organic compounds in soils. It is
believed that acceptable results can be expected for the
contaminated soils found at Libby, however a test burn would be
required to demonstrate the required dioxin destruction and
removal efficiency of 99.9999%. This alternative would be
27
-------
expected to take two years to complete, followed cy post-clcsure
monitoring of the land disposal cell 'for up to 30 years.
Capital cost to implement this alternative is estimated to
be 38,170,000. Annual 0 s M costs are 324,000 per year for the
next 30 years. The present worth cost is 37,947,200.
The major applicable or relevant and appropriate
requirements (ARARs) for this alternative are as follows.
incineration of soils will require meeting the requirements of
RdRA technology standards for a hazardous waste incineration, 40
CFR 264 Subpart D. Montana has also developed emission standards
for the operation of an incinerator. The operation of the
incinerator would have to consider applicable new stationary
source requirements under the Clear Air Act. Montana Ambient Air
Quality Standards cannot be exceeded. The excavation areas will
require closure as in alternative 5A(2), and the landfill used
for disposal of wastes and residues must be designed and operated
according to RCRA requirements and closed under Subtitle C. Land
disposal requirements would be met for this alternative because
incineration is the best demonstrated available technology (3DAT)
upon which the land disposal restricted waste concentrations were
developed. Therefore, BOAT treatment levels would be met prior
to placement in a land disposal unit. Incineration should reduce
the contaminants to concentrations less than those which would be
subject to land disposal restrictions. There is some uncertainty
as to whether air requirements for incinerators could be met.
RCRA operational and closure ARARs would be met.
Alternative 7A - Excavation of Soils and Treatment using a
Soil/Slurry Bloreaccor:
Contaminated soils from the tank farm and butt dip areas
would be placed into the bermed area of the waste pit. Front-end
loaders would feed soils into a hopper and conveyor to a primary
screening step, which would segregate debris and rock from soils.
tRock and debris would be placed in a storage pile. After further
soils screening and "shredding" to reduce all materials to a fine
size, ,soils would enter the biotreatment units.
The soil/slurry bioreactor is considered an innovative
variation of soil biodegradation processes described earlier in
land treatment. Soils would be fed into a mixer and agitated
with a concentrated solution of microbes and surfactants. The
wet slurry passes through a spray washer where large particles
are mechanically washed and ejected, and fine slurry proceeds to
a series of liquid/solid contact bioreactors. Mixers or bottom
air spargers are used to enhance aerobic biodegradation. Once
treated, the slurry is dewatered, with solids removed to land
disposal or replacement in the excavation areas. Some treated
soils may need subsequent land farming to achieve requisite
cleanup levels. The rocks and debris separated from the soil
28
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during screening may be fed separately into the slurry bioreactor
for treatment, or used in conjunction with ground vater clean up.
The soil/slurry bioreactor should achieve necessary cleanup
levels, but it is recognized that additional land farming may be
required for some batches. Whether additional land treatment is
conducted or not, a land disposal facility would be needed for
final disposition of the treated soils and possibly rock and
debris. The land disposal facility (or, if necessary, LTU) would
ha*e similar design requirements as those discussed for
alternative 5(A)2.
Evaluation conducted for the Feasibility Study Report
suggested that the soil/slurry bioreactor could achieve desired
cleanup levels within one year from implementation, but that site
demonstration may be required to verify this level of operational
effectiveness. Additionally, long-term monitoring and
maintenance requirements are established by the need for a
disposal area and/,or land treatment unit. Short-term exposure
risks may be created using this alternative. For instance, as in
all excavation alternatives, handling and processing of
contaminated materials increases the potential for exposure, as
does shredding of soils for the bioreactor and volatilization of
organic compounds. Proper design, engineering controls and
worker protection can effectively reduce the potential risks.
Long-term protection of human health and the environment is
satisfactorily achieved in a manner similar to alternatives 5(A)i
and 5(A)2, discussed above.
'* Capital cost to implement this alternative is estimated to
be $4,828,900. Annual 0 & M costs are $23,000 per year
thereafter for 30 years. The present worth cost is $4,933,500.
tli
g| The major ARARs for this alternative are similar to those
cliscussed for alternative 5A(2) above. Land disposal
restrictions are ARAR for this alternative assuming that
.treatment to less than BOAT concentrations and placement cannot
6e completed by August 8, 1990. ARARs for this alternative would
be met.
.';(•
-Action B - Ground Water Treatment, Upper Aquifer
.=; Table 14 lists the remedial alternatives considered for
ground water treatment of the upper aquifer, and classifies those
alternatives as non-treatment, control/treatment and innovative
treatment alternatives. This operable unit is focused on
treatment of contamination within the upper water-bearing units
(approximately 15 to 70+ feet below ground water surface),
referred to in this document as the upper aquifer. Table !5
presents a summary of the capital, 0 & M and present worth costs
for each upper aquifer ground water treatment alternative. In
the following descriptions, where implementation requirements are
29
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TABLE 14
REMEDIAL ALTERNATIVES FOR GROUND WATER: OPERABLE UNIT 8
NonTreaL-nent Alternatives
Control/Treatnient
Innovative Treatment
13 No Action
2B Monitoring
38 Institutional Controls
48 Pumping and Treatment
Fixed Bed Bloreactor
Rotating Biological Contactor
Granular Activated Carbon
58 In-Situ Biorernediation of Dissolved
and Sorted Organics
Sheet 1 -3f l
-------
TABLE 15
COST SUMMARY FOR REMEDIATION OF CONTAMINATED GROUND WATER
Alternative
IB
2B
3B
4B
SB
- NO ACTION
- MONITORING
- INSTITUTIONAL CONTROLS
- PUMP AND TREAT BY:
• 4B-1 - RBC
• 4B-2 - GAC
- IN-SITU
BIODEGRADATION
Annual
Operation and Present Unit1
Capital Maintenance Value Cost
Cost ($) Cost ($) Cost (J) (t /gal /day)
Yr 1 Yr 2-121
_M . _ . —
84.000
42.000
2.269.500 769.000
3,254,300 1.014.000
/
874.400 458.200
(Yr 2)
209.200
(Yr 2-6)
Yr 2-302
...... — — — — — —
84.000 1.295.300
42.000 737.900
(Yr 1-30)
57.000 8.827.000 12
57.000 11.308.000 16
57.000 2.914.500 4
1 Operational period
2 Monitoring
3 720.000 gallons of water treated per day
(2l»90r-9T3
(Ott)
Sheet 1 of 1
-------
the same tor more than one alternative, discussion will be
•presented once and referenced thereafter. Also, the description
of applicable or relevant and appropriate requirements is limited
to those which are considered major and/or unique to a certain
alternative. For .nstance, all alternatives which include
discharge or potential discharge of treated water to a surface
water body will have to meet the applicable requirements
established by State of Montana ARM 16.20.631 et seo;. However,
these will not be discussed in detail for each alternative. A
morl comprehensive list of ARARs is available in Appendix K of
the FS Report, and discussion of particular ARARs for each
alternative is contained in Chapters 6 and 8 of that report.
Alternative ?fl - Vo Action: This alternative assumes no action
will be taken to treat or contain contaminated ground water at
the Libby site. The upper aquifer presents the principal risk
concern to h :man health stemming from contamination at this site.
The no-action alternative for contamination in the upper aquifer
would not provide long-term protection of human health.
Additionally, there are long-term impacts upon the environment
through migration of contaminant plumes and potential discharge
of contamination into Flower Creek and the Kootenai River.
Although no activity would be taken in conjunction with this
alternative, there are applicable or relevent and appropriate
requirements. Continued migration of the contaminant plumes
would be a violation of the Montana Non-Degradation of Water
Quality Statutes, including ARM 16.20.1011. Continuing
contamination of the ground water would violate Montana
regulations governing Public Water Supplies. In particular, ARMs
16.20.203, 204, 205 and 207 establish maximum contaminant levels
for various organic and inorganic compounds in public water
supplies. Although the upper aquifer does not replenish a public
water supply these regulations are considered relevant and
appropriate to the problem. Discharge of contaminants into the
Kootenai River or other surface water bodies may violate relevant
and appropriate Montana Surface Water Quality requirements.
There are no costs associated with implementation of this
alternative.
Alternative 2B - Monitoring:: Monitoring would be conducted to:
(i ) Identify and track contaminant concentration gradients and
trends at locations of potential interest which would enable the
prediction of future contaminant levels on and off-site; (2)
provide ground water contaminant data showing any effects of
other remediation (i.e., soils cleanup) being conducted across
the site, and (3) provide a data base to determine changes in
potential public health and/or environmental risks associated
with ground water exposure pathways.
The monitoring network conceived for this alternative would
follow closely a program established in the spring of 1987,
during site investigation activities. Selected off-site veils
"30
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would be monitored on an annual basis, and sampling of other
selected off-site wells would be on a semi-annual basis. The
rationale for the veils to be sampled and sampling frequency is
based on well accessibility, targeting of well cwners not
participating in the buy-water plan, and the distribution of
contaminants in the ground water as developed by a statistical
model presented in Appendix E of the FS Report. Chemical
parameters to be monitored would include PAH compounds, Penta,
VQCs, dibenzo-p-dioxins and dibenzofurans, and selected metals.
A11'chemical parameters would not necessarily be monitored at
each well. For purposes of cost comparison, the monitoring
program was projected to last 30 years, although continued ground
water contamination could require a much longer monitoring
effort.
Short and long-term human health and environmental effects
are the same as for the no-action alternative. Ground water
monitoring does net of itself affect the short or long-term
effectiveness of remediation at the site, but it would provide
data to evaluate the effectiveness of other remediation actions.
Capital costs associated with this alternative are zero.
Annual 0 & M costs are estimated to be $84,000 per year for
thirty years. The present worth cost of this alternative is
$1,295,300. ARARs for the monitoring alternative are the same as
for IB. ARARs for this alternative would not be met.
Portions or all of this monitoring alternative are included
as integral parts of the following alternatives.
Alternative 3B - Institutional Controls: During the summer of
1986, the city of Libby passed.City Ordinance ti353, prohibiting
the installation of new ground water wells for the purpose of
human consumption and lawn and garden irrigation. The
institutional controls contained in this alternative consist of a
continuation of that ordinance and, if needed in the future,
passage of a similar control by Lincoln County for some areas
which could be impacted by contaminant plume migration. This
institutional control prevents use of the contaminated aquifer cy
future well owners. Evaluation of this alternative also
considers continued implementation, and possibly further
expansion, of the buy-water program instituted by Champion
International Corporation in 1985 to provide alternate water
supplies to City residents. This institutional control
encourages present well owners to discontinue use of the
contaminated aquifer.
Regulatory prohibitions precluding water use can be
immediately effective in limiting human exposure to
contamination. The ordinance against well drilling is an -example
of institutional controls preventing further opportunities for
human exposure. Expansion of the buy-water plan, should
31
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contamination migrate, will provide individuals the opportunity
to use clean water for all needs. However, the buy-water plan is
voluntary; individuals with contaminated ground water wells are
not required to take part in the program. Also, the City
Ordinance only prohibits the installation of new wells. It does
not condemn existing water wells within the contaminant plumes or
prevent owners from using them. A few well owners have chosen
not to participate and continue to use well water for irrigation
and* in at leas" one instance, for consumption. In addition, it
is difficult to guarantee the long term continuation and
enforcement of the institutional controls. Therefore,
institutional controls can be partially effective in protecting
human health in the short-term, but controls such as the City
Ordinance and buy-water plan are not considered permanent or
reliable remedies.
Capital cost to implement this alternative is estimated to
be zero. Annual 0 & M costs are approximately $42,000. Present
worth cost, based on a thirty year lifetime, is estimated to be
$737,900. The ARARs associated with this alternative are the
same as for alternative IB. ARARs for this alternative would not
be met.
Although evaluated as a stand-alone remedial alternative,
institutional controls are also an integral part of many of the
remaining alternatives considered.
Alternative 4(B)1 - Pump and Treat by Rotating Biological
Contactor (RBC): A ground water pump and treat system would be
designed to intercept the upper aquifer contaminant plume at a
location on site, immediately downgradient of the contaminant
source areas. Another extraction system would be installed
closer to the edge of contaminant plumes to halt migration,
either at the facility boundary or even off-site in residential
neighborhoods. Ground water extraction wells would be installed
to intercept zones of highest contaminant concentration. Wells
would be completed to approximately 70 feet, the lower limit of
the upper aquifer, and screened at different intervals, deter-
mined by' drilling logs. Captured ground water would be routed
via underground.piping to an on-site treatment plant. Treated
effluents would be either (1 ) reinjected into the ground water in
the vicinity of the waste pit area via a rock percolating bed
(See alternative 5B) or injection wells, or (2) discharged to the
plant's log pond and ultimately to the Kootenai River via the
existing MPDES discharge point.
Treatment of ground water in this alternative would be by
rotating biological contactor (RBC). An RBC system consists of a
series of disks covered with a film of active biomass that is
partially submerged in the wastewater. Disk rotation alternately
exposes the attached biomass to the substrate-rich wastewater and
to the atmosphere. Substrate (including the hazardous
32
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constituents) is oxidized and converted to new biomass, soluble
metabolic by-products, and gaseous end products. Controlling
factors of the RBC system are numerous, including substrate
concentration, disk rotational speed, hydraulic load, liquid
retention time, and temperature, and pilot testing would be
required to demonstrate the effectiveness for the Libby site and
refine design considerations.
;. P.rior to treatment, captured ground water would be required
to pass through an oil/water separator to remove any free-phase
product. Separated oil would be stored on site and ultimately
disposed or treated by recycle & reuse or incineration. (Oil
treatment options are considered in Sub-Action C). If the water
phase coming out of the separator contains residual free phase
oil, the stream would be pumped'through oil-absorbing media to
remove suspended oil particles prior to biotreatment.
Disposal of treated ground water would consist of either
discharge to a surface water body, or discharge to a rock
percolation bed or injection well, to assist in further source
materials remediation. Discharge to a surface water body (fire
ond and then Kootenai River) is highly dependent upon the level
f treatment which the RBC can achieve. Surface water discharge
quality would be governed by the appropriate effluent discharge
requirements, including State of Montana nondegradation
regulations.
Another method of discharging treated water is via a rock
percolation bed. This system would be used as a final polishing
step for the treated water. The system would be designed as
follows. During soils remediation large volumes of rocks will be
excavated from waste areas and separated from soils. These rocks
are expected to also have contaminants adsorbed onto surface
areas. A large trench (220 ft by 60 ft by 15 ft deep) would be
excavated on the south (upgradient) side of the waste pit, the
area of most soils contamination and largest source contributor
to the ground water. Rocks would be placed in the pit by size,
largest at the bottom. A cap of soils would be placed over a
piping system near the top to prevent freezing.
Treated water from the RBC would be trickled over the rocks
by the network of piping. Pea gravel near the top will help to
assure even distribution as the water trickles down through the
bed. It is expected that microbial activity and nutrients within
the treated effluent from the RBC would be sufficient to enhance
bacterial growth on the surface of the rocks. Bacterial growth
will help to degrade contaminants adsorbed onto the rocks and
also polish the effluent trickling down from the RBC. Because
the water will have a high biomass from the trickling bed it
should help to enhance natural degradation of the contaminant
components in the waste pit.
33
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,«n And treat ground water alternative described above
The pump and treat g controlling contaminant migration. It
would be v«y •noJC^V;eiy effective in reducing contaminant
probably would not be ery ^ ^ short.term because of
-nC!"t"t. rhiah content of contaminants adsorbed onto and
o be 10 to 20 years or longer.
rAoital cost to implement this alternative is estimated to
w «->??« 500 Annual 0 & M costs for the next 10 years are
** ;*1 to be $769*000, and $57,000 per year for the next 18
expected to be 5/^^ present vorth cost of this alternative is
S be $8,82?,000. Note: These costs are based on
to be 99 gt ;iternative on-site; installation of an
exaction system off-site, to be pumped to the on-
t?eltment system, would require a signficant increase in
capital expenditure.
The pump and treat alternative would have to meet
nriate effluent discharge requirements, including Clean
riate erri Montana Pollution Discharge
*lion System (MPDES) process, and Montana Nondegradation
i lnou!2 treated water be disposed via recharge of the
(rock percolation bed), the Nondegradation standards of
anf Ground Water Pollution Control System may apply,
"*^Ion would be into a ground water of worse quality
Sin the injected effluent, as expected. Underground Inaction
r«n?rol requirements contained in 40 CFR Part 144 are relevant
anS appropriate for the roc* percolation bed recharge system.
* monitoring network and institutional controls similar to
those described in alternatives 2B and 38 are integral parts of
this alternative.
Granular Activated Carbon;
"alternative are the'same as for alternative 4(B)i, described
earlier!?hJ following portions will only discuss those aspects
of the alternative which differ from 4(B)1.
Treatment of ground water in this alternative would be by
rranullr Activated Carbon (GAC) adsorption. Activated carbon
SXSrition is I well-established technology and is often the ^cs
effective process for removing high molecular weight compounds.
-------
The activated carbon removes organics by adsorbing them on a
.mi.croporous surface. Pore size determines the adsorption
capacity and affects the adsorption. PAH compounds and phenolics
are strongly adsorbable and easily removed by GAG adsorption.
-Many studies have demonstrated the high granular adsorption
"capacities for PAHs and Penta, and effectiveness of GAG for
removal of contaminants from ground water at a wood preservation
facility has also been demonstrated in a laboratory setting10.
•Carbon adsorption capacity is limited and it must be
regenerated thermally because neither steam nor solvent will
restore the virgin capacity. Thermal regeneration is
inconvenient and expensive, and would have to be performed off-
site at an EPA permitted facility. Changeout of GAG columns is
estimated to be required every 30 days. Construction and
operation time frame for this treatment alternative is the same
as for 4(8)1, one to two years fcr construction and startup.
Finally, it is anticipated that eifluent from this system would
be discharged to the fire pond and ultimately the Kootenai River
through the MPDES permit.
t Short and long-term effectiveness of this alternative is
nsidered to be the same as for alternative 4(B)1. Capital cost
to implement the alternative is estimated to be $3,254,300.
Annual 0 & M costs are expected to be $1,014,000 for the next 10
years, and $57,000 per year for the next 18 years thereafter.
The present worth cost of this alternative is estimated to be
$11,308,000. As with alternative 4(8)1, these costs are based on
installation of an on-site extraction system only. Off-site
extraction wells and piping would require significantly more
capital investment.
The pump and GAG adsorption treatment alternative would have
to meet the appropriate effluent discharge requirements for
surface water as in alternative 4(8)1. Additionally, RCRA
hazardous waste generation and transportation requirements will
be ARAR for spent carbon shipped off-site to a regeneration
facility,. The CERCLA off-site disposal policy, now codified in
Section I2l(d) of CERCLA, must be complied with for off-site
disposal.
A monitoring network and institutional controls similar to
those described in alternatives 28 and 38 are integral parts of
this alternative.
ternative SB - In-Situ Bioremediation: In-situ biorestoration
the upper aquifer would be based on fairly recent remediation
technology. The application considered for the Libby site is
innovative in both concept and approach. The technology upon
which this alternative is based involves the injection of
biologically important chemicals into the contaminated zone of
the aquifer. Injected chemicals, including hydrogen peroxide and
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*« «r fartilizers, stimulate subsurface microbiai
nutrients or *« orit area. These would be used to recover high
concentrattons of contaminants and any free-product accumulations
?n the area of highest ground water contamination. Water
ixtracted would undergo similar phase separation and treatment as
that descried in alternative 4(8)1 except that a fixed bed
bioreactton unit would be utilized. Treated water would be
reinjected into a rock percolation bed.
m-iection wells would be placed just upgradient from the
vaste Dit area. These wells will be placed in positions to
maximize the probability that injection of hydrogen peroxide and
nutrient will profuse the saturated zones of the waste pit area,
?he source of the highest contaminant concentrations in the
Ground water. In combination with the extraction wel'ls and
?rea?menl system described above, ground water flowing below the
waste pit in the saturated zone would be treated within a closed-
loop system involving active removal by extraction wells,
nhvsical treatment in a bioreactor, and in-situ biodegradation
Stimulation? Isolation of this waste system would help to reduce
contaminant loading in downgradient regions.
The existing pilot injection.system will be upgraded thrcugh
the installation of one or more injection wells in the vicinity
of the tank farm area. This would place injection veils in a
36
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position to inject hydrogen peroxide directly into the second
major area of upper aquifer contamination.
Monitoring will be conducted in the regions immediately
downgradient from injection wells to gauge the effectiveness of
in-situ treatment and refine maximum operational effectiveness
assumptions. Additional monitoring wells will be installed. A
monitoring network and institutional controls similar to that
described in alternatives 2B and 3B are integral parts of this
alternative.
The operational period for this alternative is estimated to
be 3 to 5 years, but there is a considerable amount of
uncertainty inherent in this projection (See appendix M of FS
Report). Should the biodegradation program achieve aquifer
cleanup in the projected time frame, the short-term effectiveness
of this approach would be considerably greater than that of any
other active ground water treatment alternative. The long-term
effectiveness of in-situ biorestoration is considered much
greater than any other alternative described, because
bioremediation would destroy organic components in both the
aqueous and non-aqueous phases simultaneously.
Capital cost to implement this alternative is estimated to
be $874,400. Annual 0 & M costs are as follows: (1) $458,200
during year 2 of remedial action, (2) $209,200 per year for the
next 5 years, and (3) $57,000 per year thereafter. The present
worth cost is estimated to be $2,914,500.
The in-situ bioremediation alternative would have to meet
similar ARARs as those presented for alternative 4(8)1, except
that no surface water discharge will occur. Recharge of treated
ground water would have to meet Montana's nondegradation policy
requirements.
Sub-Action C - Ground Water Treatment, Lower Aquifer
ft
Table 16 -lists the remedial alternatives considered for
remediation of the lower aquifer and classifies those
alternatives into nontreatment and recovery & treatment
catagories. Table 17 presents a summary of the capital, 0 & M
and present worth costs for each lower aquifer remedial
alternative. Where implementation requirements are the same for
more than one alternative in the following presentation, those
requirements will be discussed once and referenced thereafter.
Also, the description of applicable or relevant and appropriate
requirements is limited to those which are considered major
and/or unique to a certain alternative. A more comprehensive list
of ARAJls is available in Appendix K of the Feasibility Study
Report, and discussion of particular ARARs for each alternative
is presented in chapters 6 and 8 of that report.
37
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TABLE 16
REMEDIAL ALTERNATIVES FOR OIL: OPERABLE UNIT C
Nontreataent
Recovery Treataent
1C No Action
2C Monitoring
3C Institutional Controls
.4C 011 Recovery and Treatment
Recovery
Primary Recovery
Tertiary Recovery
Treatment
On-SHe Incineration
Recondition and Recycle 011
Off-Site Incineration
21990-21525 <2199Or«T4 09-01-48) (O6)
Sheet 1 of 1
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TABLE 17
COST SUMMARY FOR RECOVERY AND TREATMENT OF OIL
Alternative
1C - NO ACTION
2C - LOWER AQUIFER
MONITORING
3C - INSTITUTIONAL
CONTROLS
AC - OIL RECOVERY &
Annual
Operation and
Capital Maintenance
Cost (S) Cost ($)
(Yr 1) (Yr 6)1 (Yr 2)2 (Yr 3-5)5
___ __— ___
66.000 32.000 32.000
m. • •»
(Yr 6-30)4
___
32.000
48.000
(Yr 1-30)
Present
Value
Cost (S)
524.300
737.900
Unit
Cost
(1/9*1)
....
__ _
TREATMENT
4C-1 On-Slte
Incineration
4C-2 Recycle/Reuse
Extended Pump &
Treatment (add on
to 4C-1 or 4C-2)
2.948.700
2.948.700
2.622.400
3.187.000
505.200 1.300.100
505.200 1.300.100
32.200 9.163.600
32.000 7.206.700
1.327.300 16.164.000
31
25
1 Incineration (4C-1) and extended pump and treat system construction
2 Primary oil recovery for 4C
3 Tertiary oil recovery for 4C
4 Monitoring and extended pump and treat operation
09-02-80)
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This sub-action focuses on remediation of the'lever aquifer,
located from approximately 100 feet below ground surface to 150
feet below ground surface. Dissolved contaminant concentrations
in the lower aquifer are comparable to those in the upper
aquifer. However, the lower aquifer is thought 10 contain
significant quantities of oil product, or non-aqueous phase
liquid (NAPL), and remediation of the lower aquifer has therefore
focused on recovery of the product material which acts as an
ongoing source of ground water contamination. The FS Report
describes the problems associated with recovery of oil from the
lower aquifer in detail in Appendix F. Many of the calculations
used to evaluate the following alternatives are derived in that
appendix.
Alternative 1C - tfo Action: This alternative assumes no action
will be taken to remediate the lower aquifer. Because
contaminants present in the lower aquifer would remain and
possibly migrate further downgradient, the no-action alternative
will continue to present potential risks to human health and the
environment. Short-term impacts can be minimized assuming
continued maintenance of the City Ordinance against drilling new
wells, since it is believed there are no ground water wells
located in the lower aquifer, but institutional controls are not
Permanent nor are they fully reliable. However, long-term
impacts upon the environment are potentially substantial should
contaminated water and NAPL migrate to, and discharge in, the
Kootenai River. Additionally, the lower aquifer presents an
environmental threat to the upper aquifer as well. Should the
upper aquifer undergo an active remediation program, continued
contamination in the lower aquifer may act as a source to
recontaminate the upper.
Although no activity would be taken in conjunction with this
alternative, applicable or relevant and appropriate requirements
are the same as for the no-action alternative (1B) for the upper
aquifer. There are no costs associated with this alternative.
ABARs for this alternative would not be met.
Alternative 2C - Monitoring: The monitoring alternative consists
of sampling deep wells located just outside the leading edge of
the heavy oil pool near well 16004, sampling deep wells between
16004 and the Kootenai River, and sampling multiple completion
wells located near the Kootenai River. The purpose of the
monitoring program is to determine if oils are migrating further
downgradient, determine if contaminated ground water is moving,
and to monitor the potential for discharge of contaminated ground
.water to the Kootenai River.
Samples from wells will be collected and measured for
conductivity, pH, temperature and dissolved oxygen. Field
observations for visual appearance will be important to note if
38
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samples have a sheen, or MX?L present. 'Samples vill ce analyzed
for various parameters including PAHs, Penta, VQCs, dibenzo-p-
dioxins and dibenzofurans, and selected metals.
This alternative dees not reduce contamination in the
aquifer, so there is r.o difference in short and long-term human
health and environmental impact from the no-action alternative.
Ground water monitoring would provide the data to evaluate future
human health or environmental risks.
''•* Capital costs associated with this alternative are estimated
to be $66,000, attributable to installation of additional
monitoring wells. Annual 0 & M costs are estimated to be $32,000
per year for the next thirty years. Present worth cost of this
alternative is $524,000. ARARs for the monitoring alternative
are the same as for 1C, except that water well standards and well
installation requirements under the authority of the Montana
Department of Natural Resources and Conservation will be
considered applicable. Certain ARARs for this alternative would
not be met.
Alternative 3C - Institutional Controls: Institutional controls
are those actions that would limit potential human contact with
Contamination from the lower aquifer. Currently, there are no
private residential or commercial wells in Libby or the
surrounding area that penetrate to a depth below the upper
aquifer. This is because sufficient water production is
achievable without drilling a-deeper well. Also, as mentioned in
alternative 3B, there is a City of Libby Ordinance prohibiting
the construction of new water wells for consumption or
irrigation. Institutional controls under this alternative
consist of continuation of the Ordinance prohibiting new water
well drilling, and if needed, passage of a similar control by
Lincoln County for some areas which could be impacted by further
contaminant plume migration.
Regulatory prohibitions precluding water well drilling and
w'ater use can be immediately effective in limiting human exposure
to contamination. However, while institutional controls can be
effective in protecting human health in the short term, they are
not considered permanent or reliable remedies. Further,
institutional controls have no affect upon contaminant migration
and therefore cannot limit -the potential environmental risks.
Capital cost to implement this alternative is estimated to
be zero. Annual 0 & M costs are approximately $48,000 due to
continued monitoring of ground water. The present worth cost for
this alternative is estimated to be $737,900. The ARARs
associated with this alternative are the same as for 1C. Certain
ARARs for this alternative would not be met.
39
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4(C)1 - Oil Recovery and Treatment by On-Site
, and Extended Ground Water Pump and Treat": Oil
recovery would be accomplished through primary and thermal
recovery techniques, and through additional ground water pumping.
Although the remainder of the discussions for this and the next
oil recovery alternative will focus on design and performance of
the alternatives, the reader is referred to Appendix F of the FS
Report for a more complete explanation. Specifically, that
appendix describes the difficulties involved in the calculations,
the inability to predict where oil traps will be located due to
the extremely complex hydrostratigraphy, and the very uncertain
assumptions inherent in alternative development.
The first phase of the implementation of this recovery
system would be additional characterization of the heavy oil
present in several known oil pools. It is estimated that 10
additional ground water monitoring wells would be needed for this
task. After identification of the approximate locations of the
largest oil pools, recovery wells would be installed on 100 foot
centers. These recovery wells would be designed to recover heavy
oil in each located reservoir. Primary recovery would be
conducted in approximately 8 months. It is estimated that
approximately 100,000 gallons could be recovered from all of the
targeted reservoirs. It should be noted that this volume is
estimated to be only 5% to 14% of the original oil in place.
After completion of the primary recovery system an enhanced
thermal recovery operation would be initiated. This would entail
the injection of steam in each reservoir to heat the oil, thus
decreasing its viscosity and increasing the mobility of the oil
in the soil environment, thereby increasing the amount of oil
that can be recovered. Steam injection would involve the
installation of surface facilities, including generators, steam
strippers, heat exchangers and piping and pumps. Special
wellhead equipment would be required for the steam injection
wells. The same wells used for primary recovery would also be
used for the thermal recovery and injection wells. Steam
injection wells would be arranged to maximize efficiency of the
steam fTood. A 500-day life of the steam flood was calculated
based on the time it would require to sweep five pore volumes of
the reservoir. ' It is estimated that approximately 195,000
gallons of oil would be recovered by this thermal program, for a
combined primary/thermal recovery of 295,000 gallons,
approximately 15% to 40% of the original oil in place.
Oily water collected as part of the primary and thermal
recovery steps would require a multi-stage treatment process,
including organic/water separation and treatment of each
recovered phase. Water phase from the oil/water gravity
separator would be pumped to a dissolved air flotation (DAF).
unit. Floating oil phase would be pumped to an interim storage
40
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tank. Water exiting the DA? unit would ce pumped into a vater
treatment unit including fixed film bioreactors and effluent
discharged to the ground water through a percolation bed (See
alternative SB).
After completion cf the primary and thermal recovery
programs the installation of a pump and treat system is believed
to be the only available recovery technique to accelerate the
dissolution of the oil in the aquifer and reduce the amount of
contamination. Recovery pumps for this system would be installed
in the four steam injection wells in each target pool. A total
pumping rate of 500 gpm is assumed. It is calculated that
approximately 182 years would be required to effectively clean up
the aquifer contamination using this method.
Oil recovered by the three'recovery techniques would be sent
to storage tanks on-site. From the tank, oil would be piped to a
fluidized bed incinerator (discussed in alternative 6A) at an
approximate flow rate of 285 Ib/hr. It is anticipated that
destruction efficiency would be 99.9999% of organic contaminants.
Incineration of the oil should be completed in less than one
year.
This remedial alternative is considered to have limited
short-term impact upon the lower aquifer. The relatively rapid
withdrawal of 290,000 gallons of oil using primary and thermal
techniques is considered of little significance in reducing
overall impact upon the environment. Long-term effectiveness of
this alternative is considered acceptable if the alternative is
conducted until cleanup levels are achieved, approximately 182
years, an optimistic estimate. It is possible that oil recovery
operations could increase ground water contamination due to
dispersion of the oil throughout the aquifer during thermal
recovery.
Capital costs to implement this alternative are estimated to
be $5,571,100. Annual 0 & M costs are estimated to be the
following: $505,200 for the second year; $1,300,100 per year for
the next 3 years; and $32,200 per year for the next 25 years.
The present worth cost for this alternative is estimated to be
$9,163,600. Note that the costs have been developed based on a
30 year lifetime for comparison to other alternatives, however
the actual lifetime of the system to achieve complete remediation
has been estimated to be 182 years.
The major ARARs for this alternative are the same as for
those alternatives using injection of treated ground water
(4(B)l), and fluidized bed incineration (6A). In addition, RCRA
technology standards for hazardous waste storage tanks would be
applicable to this alternative. Monitoring requirements and
institutional controls are considered integral parts of this
remedy. ARARs for this alternative.would be met, but only after
41
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the full treatment period vas completed.
Alternative 4(C)2 - Oil Recovery and Treatment by Recycle/Reuse,_
and Extended Ground Water Pump and Treat: This alternative is in
almost all respects the same as alternative 4(C)1, except that
recovered oil would be reconditioned for possible reuse.
Therefore, only the oil treatment method is discussed in the
following sections, along with the changes in costs and
significant ARARs.
'."Under this alternative, no further treatment of recovered
oil would be conducted other than separation from water and
filtration to remove suspended particulates. Separated oil would
be periodically pumped through an in-line filter to a tank truck
and hauled to storage tanks or a customer site, if the product
can be resold. Spent filter cartridges or filter media from this
system would be crushed and land treated on site with soils in
the land treatment unit.
Capital cost required to implement this alternative is
estimated to be $2,948,700. Annual 0 & M costs are estimated to
be the same as for alternative 4(C)1 for the first five years.
Annual 0 & M costs for the next 25 years are estimated to be
$32,000. The estimated present worth cost for this alternative
is $7,206,700.
ARARs for this alternative are similar to those for
alternative 4(C)1, except there will be no incinerator ARARs.
However, there will be RCRA ARARs for hazardous waste generators
and transporters, and DOT manifesting requirements, since waste
may be taken off-site. If hazardous substances are disposed off-
site, rather than recycled and reused, Section I2i(d) of CERCLA
will have to be complied with.
Alternative 5C - In-Situ Blore/nedlatlon of the Lover Aquifer;
Chapter 5 of the FS report evaluated aquifer biorestoration as a
technology potentially applicable to the ground water
cintamination in the lower aquifer. However, biodegradation of
product is considered to be a much more difficult process than
the biodegradation of dissolved or adsorbed contaminants, as are
primarily found in the upper aquifer. The primary problem is it
is difficult to build up the biological activity to a sufficient
concentration to begin contaminant degradation. Because of the
complex problems associated with application of the technology to
the lower aquifer, the focus of the FS report was concentrated on
oil extraction methods using oil field technology. As
demonstrated in the description of alternatives 4C( 1 ) and 4C(2),
product extraction and ground water treatment using conventional
technology at the Libby site would be very expensive and not very
effective in either the short term or long term. Therefore, EPA
is evaluating in-situ bioremediation in this remedy selection as
another alternative, based upon information in the FS Report and
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the administrative record.
Application of this process to the lower aquifer would be in
theory similar to alternative SB. Implementation of this
alternative would require extensive field testing and design
considerations, because: (1) the hydrostratigraphy of the system
is very complex, ( 2 ) successful testing would require isolation
of a product pool which could be evaluated for biodegradation
effectiveness through time, (3) less is known about contaminant
transport in the lower system, due primarily to the shortage of
wells 'and inconclusive aquifer (pump) tests.
While remediation of the lower aquifer has focused on the
problems associated with oil removal or degradation, EPA feels
that a combination of oil recovery and product dispersion, with
biodegradation, is the only potentially viable cleanup method.
In order for biorestoration to be effective, it will be necessary
to remove as much product from the aquifer as possible.
Additionally, secondary or tertiary oil recovery techniques may
then be used to facilitate biorestorative processes. For
instance, it has been documented in Appendix F of the FS Report
that thermal removal of oil may disperse contaminants throughout
aquifer, into matrix pores. This deconcentration of product
ould allow biologic activity to occur more rapidly because of
greatly increased contaminant surface area.
Bioremediation, even in conjunction with oil recovery
technologies, could potentially be as or more effective than
traditional pump and treat aquifer solutions, and much less
costly. Without the benefit of field testing estimates of short
or long-term effectiveness are not possible. Costs to implement
such an alternative are also unknown, but it is believed that an
objective, well-developed field program, to be conducted for two
years, would require between $300,000 and $500,000. ARARs for an
in-situ bioremediation alternative are the same as for •
alternative 5B. ARARs for this alternative would be met if the
technologies prove successful and the program is implemented in
fall. ARARs would not be met for the pilot testing program
necessary at this time.
. •
IX. Summary of Comparative Analysis of Alternatives
All of the remedial action alternatives which passed an
initial screening process were subjected to a detailed evaluation
in accordance with OSWER Directive 9355.0-19 and Section
300.68(h) of the National Contingency Plan. Alternative 5C was
also evaluated against these criteria, and that evaluation is
^reflected in the administrative record and this document. The
Detailed analysis was conducted using nine criteria developed to
assure remedy selection compliance with Section 1 21 (b) ( 1 ) ( A-G ) of
CERCLA. The following sections will briefly compare the
alternatives within each sub-action to the evaluation criteria.
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Further information is available in Chapter 8 of the ?S report
and other documents in the administrative record.
Sub-Action A - Sois/Source Areas
;. Overall Protection of Human Health and the Environment:
Alternatives involving land treatment,with and without a liner,
incineration, and the soils/slurry bioreactor are all considered
fully protective of human health and the environment. Each
remedial action minimizes the potential exposure pathways by
reducing the number of areas in which contamination will be found
and'by covering the final disposal area with an impermeable
cover. The land treatment with a liner alternative is slightly
more protective of the environment in that the bottom synthetic
liner will provide another protection against contaminant
leaching. As a stand-alone alternative, capping of existing
contamination areas is considered less protective of human health
and the environment because of the greater potential for
continuing contaminant leaching to the environment.
Institutional controls can help to prevent direct human exposure
to contaminants, but the environmental threat due to contaminant
leaching is even more substantial than for the capping
alternative. The no-action alternative is not protective of
human health or the environment.
2. Compliance vith Applicable or Relevant & Appropriate
Requirements: Alternative 6A, incineration, is the treatment
alternative compliant with ARARs if air quality standards can be
met. Both land treatment alternatives and the soil/slurry
bioreactor may require a demonstration of no-migration to obtain
a variance from the land disposal restrictions so that treatment
can continue until cleanup criteria are reached, but these will
also meet ARARs. A variance from the land disposal restrictions
based on no-migration should be easier to obtain if a lining
system is used in a land treatment unit. Because incineration
would reduce organic contamination to below established BOAT for
the restricted wastes, prior to placement in a land disposal
unit, it will be in full compliance with the land disposal
restrictions. The capping alternative can also be conducted in
accordance with all ARARs involving technology standards and
closure/post-closure requirements. Excavation of contaminated
areas would meet ARARs. ARARs would not be met for the no-action
and institutional control alternatives.
3. Long-Term Effectiveness and Permanence: Alternatives using
incineration,land treatment and the soil/slurry bioreactor are
all effective remedies which will provide long-term protection of
human health and the environment because the majority of
contaminants will be destroyed and the remainder immobilized.
Each alternative reduces contaminant levels to a great extent,
and the remedies are considered permanent because there will be
only residual contamination left and the cover will require
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routine maintenance. Capping alone can provide some long-term
protection but it is not considered a permanent remedy because
the primary protection (cap) is subject to failure and treatment
is not part of the remedy. The impacts of cap failure for this
alternative are much greater than for cap failure of any of the
treatment alternatives because contaminant levels will still
remain high and therefore pose a threat to human health and the
environment. Neither institutional controls nor the no-action
alternative are considered permanent solutions and neither
provide long-term protection.
'• «
4'. deduction of Mobility, Toxicity, or Volume: All of the
treatment alternatives significantly reduce the toxicity of
contaminated soils through contaminant destruction. Both land
treatment alternatives and the soil/slurry bioreactor reduce the
mobility of contaminants through treatment and isolation in a
disposal area. Land treatment with a liner system decreases the
potential for contaminant mobility even more through engineering
controls. Incineration can ultimately reduce the mobility of
contaminants, although emissions releases may mobilize some
constituents. Incineration will reduce the volume of
contaminated materials; land treatment and the soil/slurry
alternative will only reduce volumes slightly through organic
carbon destruction. Capping will reduce contaminant mobility,
but not in a permanent manner. The no-action alternative and
institutional controls will not reduce MTV.
5. Short-Term Effectiveness: The capping alternative would
provide the most immediate short-term alleviation of public
health and environmental threat by rapidly reducing the
opportunity for contaminant exposure. Among 'the treatment
alternatives, incineration could be completed within one year
after pilot start-up, while the soil/slurry bioreactor would take
approximately 2 years to reduce contaminants to acceptable levels
and the land treatment alternatives would take 4 to 6 years. All
three treatment alternatives would create other, short-term
exposure potentials via excavation and movement of contaminated
soils and volatile or combustion emissions. Institutional
controls can help to quickly reduce potential for public exposure
•to contaminants. The no-action alternative is not effective.
6. Implement ability: The no-action alternative and
institutional controls are the most easily implemented
alternatives considered. Capping technology is well developed
and the materials and services required are available. The land
treatment alternatives are the most readily implemented of the
treatment actions being considered because the technology is well
understood and the bench scale and pilot scale tests at Libby
have provided needed design criteria. The soils/slurry
bioreactor technology is available but demonstration would be
required to evaluate rate of effectiveness and refine design
criteria. Mobile incineration units are available, but extensive
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demonstration of combustion efficiencies make this possibly the
least easily i-? le.r.ented alternative. Air prcble.-.s -specific tt
the Libby area may negatively effect incinerator i.-nplementa-
bility.
7. Cost: Table 13 provides a comparison of the costs for the
soils and source areas remedial alternatives. The n.o-action
alternative would require zero expenditure, while institutional
controls would require minimal capital and annual costs. Of the
active alternatives, land treatment without a liner would require
the.least capital outlay, followed by capping of source areas,
land'treatment with a liner, the soils/slurry bioreactor and the
most expensive alternative, incineration. Incineration, soil/
slurry bioreactor and the land treatment alternatives all have
similar annual 0 & M cost requirements for most of the thirty
year lifetime, although the land treatment alternatives will
require extensive operations costs during years 2 through 5.
Annual 0 & M costs for capping are approximately 50% higher than
the other, active alternatives. Of the treatment or containment
alternatives, land treatment without a liner is predicted to have
the lowest present worth cost, followed by capping, land
treatment with a liner, soils/slurry bioreactor and finally
incineration. [Note: All costs presented are estimates]
8. State Acceptance: The State of Montana has concurred with
the remedy selection for this sub-action. The State has agreed
that a liner is a necessary element of the land treatment unit.
One recommendation the State of Montana has made is that
institutional controls prohibiting residential development, in
soils clean up and treatment areas, be included as a required
element of the remedy. This prohibition has been included.
9. Community Acceptance: Specific comments submitted by the
public during the public comment period, and Agency responses to
those comments, are attached as part of the Responsiveness
Summary Section. The following summarizes some of the concerns
raised by the public over the methods considered for soils/source
areas clean up.
So,me members of the audience at the public meeting
questioned the effectiveness of removing only the soils/source
materials in the unsaturated zone. They felt that most of the
contamination would be deeper than the water table. Another
concern of some citizens is that institutional controls can be a
violation of individual property rights. One commenter also
mentioned *:hat use of a cap over the treatment areas is a waste
of time sir.ce the ground water flow would continue to spread
contamination. However, there were no comments directed at the
alternative selection, and EPA therefore believes that in general
the community is accepting of the preferred alternative.
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Sub-Action 8 - Ground Watef Treatment, Upper Aqufer
i . Overall Protection of Human Health and the Environment:
Technical evaluation of ground water clean up alternatives
indicates that treatment alternatives using pump and treat
technology and in-situ bioremediation can all adequately protect
human health and the environment by eliminating contaminants, and
thus exposure risk, from the aquifer. Institutional controls can
provide some protection to human health by limiting exposure, but
it :pr,o-vides no environmental protection. Monitoring and the no-
acti'on alternative provide no protection to human health or the
environment.
2. Compliance vith Applicable or Relevant and Appropriate
Requirements: All of the ground water treatment alternatives can
be implemented to assure compliance with all potential ARARs,
except potentially for the Montana Non-Degradation rules for
ground water. In order to achieve compliance with this ARAR,
off-site pumping of contaminated ground water may have to occur
to halt ground water plume migration. This opinion is based on
the assumption that ground water plumes are migrating, and that
the Montana Water Quality Bureau will consider plume migration a
jion-degradation rule violation. Without an off-site pump system,
PL he treatment response actions would have to be placed on a
compliance schedule and this would achieve compliance with the
Statute. The institutional controls, monitoring and no-action
alternatives would not achieve compliance with many ARARs,
including MCLs (benzene) established by the Safe Drinking Water
Act; Montana non-degradation laws for ground water; and, if
plumes migrate to the Kootenai River and/or Flower Creek, Montana
rules on non-degradation of surface waters.
3. Long-Term Effectiveness and Permanence: Alternatives 4B( 1 ) ,
pump and treatment of ground water using a rotating biological
contactor, and 5B, in-situ bioremediation, provide long-term
remediation effectiveness. These remedies are considered
permanent in that they degrade/destroy contaminants to acceptable
cleanup levels. Alternative 4B(2), pump and treatment of ground
water using granular activated carbon, provides long-term relief
from ground water contamination, but the remedy is not considered
as permanent because contaminants are not destroyed but
transferred to a different media (activated carbon) which will
then require thermal regeneration. Institutional controls,
monitoring and no-action alternatives will not provide long-term
protection of human health and the environment.
4. Reduction of Mobility, Toxicity or Volume: The in-situ
ibioremediation alternative and pump and RBC treatment alternative
both reduce mobility, toxicity and volume of contaminants in the
ground water. Pump and GAG treatment alternative will reduce
mobility and toxicity in the ground water, but contaminants are
transferred to another media. Institutional controls, monitoring
47
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and the no-action alternatives will not reduce MTV.
5. Short-Term Effectiveness: In-situ bioremediation is the most
effective treatment alternative in the short-term because it is
estimated that this response action could be completed in 3 to 5
years, depending upon required cleanup levels. Both pump and
treat alternatives would require approximately 10 years to be
effective. Institutional controls provide an effective short-
term remedy in that they can reduce the potential for human
exposure immediately. Monitoring and no-action alternatives do
not achieve a level of protectiveness, and are therefore not
effective.
6. Implement ability: No-action and monitoring alternatives are
very easily implemented since no additional design, construction
or procurement actions would be required. Institutional controls
are already in place in Libby, although some expansion of the
buy-water plan may be required. Additional institutional
controls could be implemented relatively easily for areas outside
the city of Libby. Of the three treatment alternatives, in-situ
bioremediation is probably the most easily implemented because
equipment is available and operational knowledge was gathered
during site pilot testing.
7. Cost: Table 15 presents a comparison of the costs required
to implement and maintain the considered alternatives. The no-
action alternative requires no capital or 0 & M expenditures.
Institutional controls are the least expensive of the other
alternatives to implement, and monitoring is next. Annual 0 4 M
costs and present worth costs of these two alternatives are also
much lower than any of the treatment alternatives. The least
costly treatment alternative to implement is in-situ
biodegradation, followed by pump and treat with RBC and then pump
and treat with GAC. Annual operating costs for the in-situ
alternative are also lower, and for fewer years, than the pump
and treat alternatives. Annual 0 & M costs for all three are
about the same once the desired cleanup has been achieved. In-
situ bioremediation is also valued less in terms of present worth
cost than the other treatment alternatives. [Note: All costs
presented are estimates]
8. State Acceptance: The State of Montana has concurred vith
the selection of In-Situ Bioremediation as the preferred clean up
alternative for the upper aquifer.
9. Community Acceptance: Specific comments submitted by the
public during the comment period, and Agency responses to those
comments, are included with this remedy selection as part of the
Responsiveness Summary. The following summarizes some of the
public concerns over the methods considered for ground water
clean up.
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Some citizens at the public meeting vere worried about '-.he
impact that high volume pumping wells could have on residential.
wells in the vicinity. Another citizen questioned what would
happen to the ground water bacterial populations after clean up.
Many individuals stressed the need for the buy-water plan to be
extended, if ground water plumes migrate, to newly impacted
residences. However, there were no negative comments directed at
the preferred alternative, and EPA therefore believes that the
community is accepting of the recommended remedy.
Jub-Actioft C - Ground Water Treatment, Lower Aquifer
. 7 . Overall Protection of Human Health and the Environment:
Institutional controls provide the most immediate and most
assured protection of human health of the alternatives considered
for this sub-action, but this protectiveness is considered
neither permanent nor reliable. Oil recovery options, when
combined with a ground water pump and treat scenario, may some
day provide protection of human health and the environment. At
the least, extensive pump and treat could prevent contaminants
from migrating to the Kootenai River. The additional alternative
considered in this remedy selection, in-situ bioremediation, may
o provide protection of human health and the environment if it
s proven to effectively degrade contamination in the aquifer.
The monitoring and no-action alternatives are not protective.
2. Compliance with Applicable or Relevant and Appropriate,
fleguirernent_s_: In order to be fully compliant with potential
ARARs an alternative which halts plume migration would have to be
implemented (see discussion on ARARs compliance in the upper i
aquifer and non-degradation issues) and MCLs would have to be
achieved throughout the aquifer. Oil recovery and treatment
(through incineration or recycle) with extended ground water pump
and treatment are the only alternatives evaluated in the FS
Report which could achieve compliance. Monitoring, institutional
controls and no-action alternatives may all violate benzene MCL
and non-degradation policies. The in-situ bioremediation
al'ternative may achieve ARARs, if implemented in full. A pilot
program,evaluating in-situ bioremediation and other aquifer
remediation techniques would not meet ARARs, but would be
eligible for a.waiver of ARARs as an interim remedy.
3. Long-Term Effectiveness and Permanence: The in-situ
bioremediation alternative could theoretically provide long-term
effective protection of human health and the environment. This
alternative would also be considered a permanent remedy because
contaminant levels would be degraded in-situ until established
cleanup levels are reached. However, an in-situ biorestoration
program may also take a long time to reach desired cleanup
levels. Oil recovery and treatment alternatives could eventually
provide long-term protection, but treatment would require an
estimated 180+ years to achieve desired protectiveness levels.
49
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Institutional controls, monitoring and no-action are not
considered effective in the long-term.
4, Reduction of Mobility, Toxicity or Volume: An in-situ
bioremediation program could reduce mobility, toxicity and volume
of contamination if effective at reducing oil concentrations.
Oil recovery and treatment options may reduce volume of
contamination and eventually toxicity, but thermal recovery
methods in situ may actually increase the mobility of some
contaminants. Institutional controls, monitoring and no-action
are all equally ineffective at reducing MTV.
'• »
5. Short-Term Effectiveness: Institutional controls would
provide the most immediate and assured protection from exposure
to lower aquifer contamination. Mo-action and monitoring
alternatives will not help achieve protection and are therefore
not effective. Oil recovery effectiveness would be limited in
the short-term, and adverse environmental effects could actually
be a result of implementation of this alternative through
contaminant mobilization. Mobilization of the contaminants could
also enhance biodegradation processes, however. In-situ
bioremediation alone would not be as effective in the short-term
for the lower aquifer as the upper because of the presence of
large amounts of product in the lower aquifer. Further
evaluation.of this criterion for an in-situ bioremediation
program could only come after pilot testing.
6. Implement ability: The no-action, monitoring and
institutional control alternatives are very easy to implement
quickly and inexpensively. Implementation of the oil recovery
options would be difficult. Extensive design would have to be
conducted in conjunction with field investigations including an
intensive drilling program. Specialized equipment would have to
be created for the steam injection wells. Alternative 4C(1),
which utilizes incineration of recovered oils, would be
restricted by the same design criteria as for the soils
incineration alternative previously discussed. An in-situ
bioremediation alternative (5C) could theoretically be
implemented much easier than pump and treat scenarios, but
extensive design work and modeling to determine engineering
controls' would have to be conducted. Also, because an in-situ
program would probably be combined with oil recovery,
implementation 'requirements may be quite similar.
7. Cost: Table 17 presents a summary and comparison of the
costs required to implement and maintain the alternatives
considered for operable unit C. (Note that costs for alternative
5C are not included in the table). The no-action scenario would
require zero capital or 0 & M expenditures. Lower aquifer
monitoring would require some capital outlay to install new
monitoring wells. Annual 0 & M costs for the monitoring
alternative are lower than for institutional controls, which
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would require no capital outlay. Alternatives requiring oil
recovery are similar in cost, except that incineration costs
would increase number 4C(1) by over $2.5 million initially. The
.present worth cost of the oil recovery and incineration
alternative is therefore greater than the oil recovery and
recycle/reuse alternative. Addition of extended pump and .treat
ground water systems to either of these alternatives (necessary
for ground water cleanup) would dramatically increase costs.
Because alternative 5C is considered a conceptual alternative
which requires laboratory and field testing to prepare an
effective analysis, costs have not been included in this
evaluation. However, EPA suggests that a well designed pilot
study of this alternative for the lower aquifer would cost
approximately $300 to $500 thousand dollars. [Note: All costs
are estimates]
8. State Acceptance: The State of Montana has concurred with
the decision to ma)ce the remedy selection for the lower aquifer
an interim remedy. The State has agreed that field and
laboratory tests should be conducted to evaluate the
effectiveness of in-situ bioremediation, in conjunction with oil
recovery techniques, for the lower aquifer.
Community Acceptance: Specific comments submitted by the
public during the public comment period have been addressed by
EPA and responses to those comments are included as part of the
Responsiveness Summary attached to this remedy selection. In
general, there has been no community feedback concerning either
the alternatives considered or the preferred alternative for the
lover aquifer. The EPA therefore believes that the public is
generally accepting of the recommended remedy.
X. Selected Remedes and Cleanup Determinations
Sois/Source Areas Excavation and Clean Up and Treatment Criteria
The alternative preferred by EPA to remediate contaminated
soils and-sources areas is number 5A(1), Excavation of
Contaminated Soils and On-Site Land Treatment With a Liner. As
developed in the FS Report, this alternative combines an
innovative treatment technology, enhanced in-situ bicdegradation,
with traditional land farming to effectively reduce soil
contaminant concentrations. Contaminated soils located in the
unsaturated zone will undergo a two-step enhanced biodegradation
treatment. Initial treatment will be conducted in the waste pit
area. Upon reaching an optimum contaminant degradation lifts of
Jsoils will be transferred to the second phase, lined treatment
cell, which will also act as the final disposition location.
A combination of bioremediation treatment processes will te
utilized to degrade organic compounds in soils in the saturated
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zone. A closed loop, nutrient and oxygen-rich ground vater
infection and extraction system will be the primary technique
used to degrade conta.TU.-.ants id sorted on soil T.atr.zes ar.d :.-. : 11
product in the saturated zone. Ground water extraction and
physical treatment will speed the process. This system should
effectively halt any further contaminant migration outside of the
waste pit area.
Determination of excavation and treatment criteria for soils
has been conducted using two methods: (1) Evaluation of the
standards supplied in various ARARs, such as BOAT concentrations
in :t^\e. Land Disposal Restrictions, and (2) using human health
risk" assessment to determine contaminant concentrations which are
protective of human health, while giving consideration to site-
specific conditions. Land disposal restrictions are discussed in
detail in the Feasibility Study Report, Section 4.5.2. Cleanup
criteria for certain compounds have been evaluated in Section 4.7
of the FS Report. EPA has determined that the following cleanup
levels and treatment levels are protective of human health and
the environment and are in compliance with ARARs, and the
remediation activities for soils and source areas will be
required to meet these levels.
1 . Excavation of Butt Dip, Tank Farm and Waste Pit Areas:
These areas will be excavated to an acceptable cleanup level,
defined as: All soils, debris or other "source" material from
these areas which are contaminated with concentrations of
carcinogenic PAH compounds greater than 88 milligrams per
kilogram (mg/kg) will be removed and treated to the (see below)
treatment levels. This level have been chosen because: (1) 88
mg/kg of carcinogenic ?AHs is selected as the "indicator" cleanup
level because it should provide a relatively good visual
identifier of contamination; (2) PAHs are ubiquitous in thesel
three areas and, based on extensive site investigations, if they
are not present, other contaminants should not be; and, (3) ijj
carcinogenic PAHs are present below the cleanup level, risk •>
analysis indicates the potential human health threat will be t
acceptable (10~5 risk construction scenario), and backfillingt/and
capping of the areas will reduce the potential for exposure to
the residual contamination and meet relevant and appropriate RCRA
closure, requirements. A sampling and analysis program will be
developed to assure concentrations remaining in or near /
excavation areas do not exceed these cleanup/treatment levels.
2. Contaminant Levels Prior to Placement in the'Final Land
Treatment Unit: Because of a capacity extension, land ban :
concentration levels for the placement of waste soils into the
final treatment unit do not need to be met prior to August 8,
1990. If it is determined that the land ban concentration levels
cannot be met after this date, a no-migration petition will be
prepared, using data from the 1988 land treatment demonstration
unit and, if possible, from the 1989 field season.
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3. Treatment Levels for Excavated Soils: Soils, debris or
other "source" material from the waste pit, butt dip and tan*
farm areas will be treated to an acceptable cleanup level,
defined as: (1) Total carcinogenic PAH concentrations are less
than or equal to 88 mg/kg; (2) Individual PAH compounds
napthalene, phenanthrene and pyrene, will be less than or equal
to 8.0 mg/kg, 8.0 mg/kg, and 7.3 mg/kg, respectively; (3)
2,3,7,8-TCDD equivalency concentrations of chlorinated dibenzo-p-
dioxJ,n« and dibenzofurans combined are less than or equal to
O.OO'l mg/kg; and (4) Pentachlorophenol concentrations are less
than or equal to 37.00 mg/kg. PAH and 2,3,7,8-TCDD equivalency
concentrations were developed using cumulative target risk
calculations to determine an acceptable range of risks using
different land use scenarios. The 88 mg/kg treatment/cleanup
level represents a 10"^ risk using a construction exposure
scenario. The additive risk using a residential exposure
scenario, although not calculated exactly, would be slightly less
than 10~4 (within the acceptable range of risk). The residential
scenario is considered highly unlikely for the Libby site and
institutional controls will prohibit residential development in
waste areas. The pentachlorophenol concentration was selected
because the applicable BOAT concentration for land disposal
Restriction of this compound is 37.00 mg/kg, which is a relevant
and appropriate requirement for the end of treatment. This
number is also consistent with 40 CFR Part 264, Subpart M
requirements, which require maximum destruction of contaminants
in a land treatment unit. Individual treatment concentrations
were also selected for napthalene, phenanthrene and pyrene, based
on the BOAT treatment concentrations. After August 3, 1990, if
the treatment concentrations for penta, or napthalene, or
phenanthrene, or pyrene cannot be achieved prior to placement in
the land treatment cell, a no migration variance will satisfy the
land disposal requirements.
4. Treatment Levels for Materials in the Saturated Zone:
Treatment levels in the saturated zone will be based upon
leachate concentration. In other words, ground water exiting the
saturated zone below the waste pit area will be required to be at
concentrations less than or equal to the ground water cleanup
levels established in the following section. Compliance with
this requirement will be monitored by analysis of samples
collected at waste pit area extraction wells.
Institutional controls, during the treatment activities and
after completion of capping, will be required as part of this
remedy.
Ground Water Cleanup Levete - Upper Aquifer
The alternative preferred by EPA to remediate contaminated
ground water in the upper aquifer is number 53, In-3itu Ground
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Water Biorerr.ediation . As developed in the FS Report, this
alternative should effectively treat ground water contamination
in place, an innovative approach considered more effective
other traditional ground water clean up options. The closer loop
treatment process described in the soils treatment alternative
will reduce further contamination of the ground water by
retarding leaching of contaminants from the waste pit source
area. An in-situ, enhanced biorestoration program, separate from
the processes employed to degrade contamination in the saturated
zone of the waste pit area, will be initiated in the upper
aquifer to begin reducing contaminant levels near the tank farm
and :in, downgradient regions.
Ground water cleanup criteria have been determined by
examining and considering pre-established, ARAR standards such as
Safe Drinking Water Act Maximum Contaminant Levels; use of human
health risk assessment to determine contaminant concentrations
which are protective of human health; and, when necessary,
technology limited values. 10~^ target risks have been
calculated for certain compounds in Section 4.7.1 of the
Feasibility Study Report. Section 4.3 of the FS Report discusses
the potential ground water ARARs, and Section 4.6 discusses other
criteria, advisories and guidance which were considered in
determining the cleanup levels.
EPA has determined that ground water cleanup levels will be
the following for the upper aquifer: (1) Total non-carcinogenic
PAH compounds in ground water will be present in concentrations
no greater than 400 nanograms per liter (ng/L) and carcinogenic
PAH compounds will be present in concentrations no greater than
40 ng/L. The carcinogenic PAH concentration has been based on
risk calculations presented in the FS report and achievable
detection limits, because the determined 10~6 target cleanup
level is not reliably detectable using current analytical
technology. The risk presented by leaving this concentration of
carcinogenic PAH in ground water is 10~5. i-ne carcinogenic PAH
concentration of 40 ng/L is not a level uniformly detected at
many analytical labs at the present time. Rather, it represents
a number which some laboratories state can be achieved at the
present time, and which should be more reliably achievable
through %ime. Therefore, sampling and analysis of ground water
samples to determine compliance with cleanup goals will have to
be conducted under strict protocol. The clean up level for total
non-carcinogenic PAH concentrations is based on evidence that
many creosote compounds are capable of promoting the carcinogenic
activity of other, cancer causing compounds. Because the
carcinogenic PAHs clean up level is higher than a 10~6 risk
level, and because a newly listed carcinogen (penta) will be
present in concentrations most probably higher than normal for
such a compound, EPA believes that a conservative clean up level
for total PAH compounds is warranted. This decision is further
justified as a means to assure that other potentially hazardous
54 '
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creosote compounds, not typically analyzed !or during t
site investigations, will be destroyed to acceptable
concentrations as well. (2) Pentachlorophenol will be present in
concentrations no greater than 1.05 milligrams per liter (mg/L).
This concentration is based on a lifetime health advisory, (3)
Benzene will be present in concentrations no greater than 5
micrograms per liter (ug/L). (4) Arsenic will be present in
concentrations no greater than 50 ug/L. Arsenic and benzene
concentrations were selected based on Maximum Contaminant Levels
established by the Safe Drinking Water Act. (5) Finally, other
orga-rtic and/or inorganic compounds which may be present in the
ground water will be at concentrations which pose a human health
threat no greater than 10""^.
Attainment of cleanup levels for the compounds used as
ground water indicators (above) should assure that other organic
or inorganic compounds will not be present in concentrations
potentially harmful to public health and/or the environment. For
instance, volatile organic compounds such as methylene chloride
and tetrachloroethylene have been detected in some aqueous
samples. As already noted, creosote contains many organic
compounds which have not typically been looked for in Libby
samples. Treatment to reduce the primary contaminants, Penta and
§AH compounds, should effectively reduce these other chemicals to
Acceptable concentrations. However, cleanup level 15 above
assures that overall ground water cleanup will achieve a target
human health risk not greater than that created by the analytical
technology limited PAH target level.
Institutional controls and monitoring are also required in
conjunction with this remedy. When acceptable levels are
achieved, institutional controls can b'e discontinued. Monitoring
will be required as long as hazardous ^substances remain.
Ground Water Cleanup Levels - Lower Aquifer |
Because none of the alternatives^ presented for clean up of
t'he lower aquifer have been demonstrated to effectively reduce
contaminant concentrations in a reasonable timeframe, EPA has
decided that a test of in-situ bioremediation, in conjunction
with oil recovery/dispersion techniques, should be attempted.
This feasibility testing of remediation technologies is selected
as an interim remedial measure. A final remedial measure will be
chosen at the conclusion of the pilot:program. This remedial
measure is included in the descriptions as alternative number 5C.
A biorestoration test program similar in scope to that conducted
for the upper aquifer will be initiated. The pilot test will be
conducted to determine if enhanced biorestoration of the aquifer,
alone and in conjunction with oil recovery techniques, is a
viable means of aquifer cleanup. In conjunction with this
remedy, institutional controls and continued monitoring are
required which will provide protection of human health and t'r.a
55
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At *his time. ARAR requirements are waived on a
-..mpor.ry M.l."^.d vill fe. r.-.v.iu,t.d during th. next r.c
of decision.
Treatment of the ground water in the upper and, if required,
l^ltlrl will be continued until the cleanup levels are
^fined and maintained through time. Once cleanup levels are
*JJ tn!d it is anticipated that treatment will continue for some
attained, ** *!*3 D«riod. assure residual or delayed-
a%y:LUcontaminantrarrnot re-entering the system. Monitoring
rf ^und waler qCality will continue after acceptable contamin-
ant levels ha" been attained and maintained, and remediation has
stopped.
The Statutory Determinations
The remedy selected for each operable unit must satisfy the
requirements of Section 121 of CERCLA. Specifically, Section
il??b' oTcERCLA requires that any selected remedy be protective
of human health and the environment, be cost effective, and
utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable. Section I21(d) of CERCLA states that
remedial actions that leave any hazardous substance, pollutant or
clntani?nan? on-site must meet, upon completion of the remedial
action a level or standard of control that at least attains
standards, requirements, criteria or limitations that are legally
aDDlicable to the hazardous substance, pollutant, or contaminant
concerned, or are relevant and appropriate under the
circumstances of the release or,-threatened release. Section
I2l(d) allows EPA to waive these requirements under certain
limited conditions. "•?
EPA has concluded that theSselected remedy is consistent
with these requirements of CERCLA. The following section
provides a narrative description of how the selected remedy meets
the specific statutory requirements.
ft
Pmtection of Human Health and the Environment
Soils excavation and contaminant biodegradation will
rframatically reduce risks to human health and the environment.
Excavation of contaminated soils from the butt dip and"tank farm
areas will centralize all source materials in the waste pit area.
The butt dip and tank farm excavations will be backfilled and
closed with a protective cap to assure there is no residual
contamination exposure potential via soils contact or ingestion.
Treatment will be conducted in the waste pit area until a
specified level of degradation is reached; materials will then be
transferred to the lined land treatment unit and disposal cell.
After excavation of partially treated soils from the waste pit
56
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the area vill ce cacicfiiled and closed vith a protective cap to
reduce residual contamination exposure potential. Final
treatment will be conducted in a land treatment unit, which will
be designed to control runoff, prevent runon, and halt downward
contaminant migration. Soils treatment will continue until an
acceptable level of cleanup (see previous sections) is achieved.
This cleanup level is considered by EPA protective of human
health and the environment. As an assurance, a protective cap
wi'l be placed over the land treatment area upon treatment
Environmental risxs posed by soils contamination are
primarily through leaching of contaminants into the ground water.
The remedies selected will dramatically reduce the leaching
potential by removal of soils from some uncontrolled areas and by
establishing a closed-loop treatment cell at the waste pit area
to assure contaminants in the saturated zone are treated and
cannot migrate further downgradient . There should be no
environmental risks posed by the land treatment unit. In order
to assure contaminants will not migrate from the cell, and to
ensure compliance with ARARs, a demonstration of no-migration
will be done. The basis for this demonstration will be extensive
technology field testing conducted on site during the summer of
|k988, including air emissions sampling and modeling, and
Engineering controls as needed to assure contaminant migration
prevention, including a liner system.
Existing institutional controls will continue to prevent
human exposure to contaminated ground water in the upper aquifer
; until acceptable contaminant levels are reached. The in-situ
bioremediation alternative selected will provide long-term
protection of human health and the environment by degrading
contaminants within the aquifer system.' This ground water
treatment alternative will be conducted until levels considered
protective of human health and the environment are achieved.
Monitoring will be conducted to ensure protective levels are
maintained.
t
Institutional controls will continue to prevent human
exposure to contaminated ground water in the lower aquifer during
the pilot program and beyond. Monitoring will be conducted to
assure continued environmental protection. The final remedial
action, to be decided upon completion of the pilot program, will
address protectiveness again. If the test program is not effect-
ive, monitoring and institutional controls may be relied upon to
prevent human exposure and identify environmental threats.
Implementation of the remedies selected should not create
.unacceptable short-term risks or adverse cross media impacts.
57
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Attainment of
The remedies selected for soils clean ;p and t'r.e :p?er
aquifer, coupled with a no migration petition, will attain aii
aoolicable or relevant and appropriate requirements. The
Hazardous and Solid Waste Act requires BOAT treatment of KQOi
sludae prior to land disposal. Because land treatment is
considered a form of land disposal, and because the contaminated
soils are K001 soil and debris once mixed in the waste pit, these
retirements are considered applicable to the placement of waste
in the final treatment cell. It is unknown at this time whether
land treatment at the Libby site will reduce concentrations of
contaminants to below BOAT concentrations, so that the land
disposal restrictions would eventually be met. However, because
placement will probably occur after August 8, 1990, a
demonstration of no-migration petition will be prepared and
submitted to EPA to allow continued use of the innovative
biodegradation technology at the Libby site. This will comply
with the land disposal restrictions.
Also, as noted earlier in this document, ground water non-
degradation ARARs may not be met should plumes in either aquifer
continue to migrate. However, migration is not expected and the
upper aquifer remediation should result in compliance for that
aquifer. A waiver of relevant and appropriate requirements of
the Safe Drinking Water Act and other ARARs for the lower aquifer
is invoiced based on technical impracticability and the fact that
this is an interim remedy which may achieve compliance.
Tables 18, and 19, list the ARARs identified for the
remedies selected.
There are some potential ARARs which are worth noting in
this decision document because they could potentially impact
remedy implementation in the future. They are all compound-
specific issues.
A change in the MCL for arsenic is anticipated to be
proposed in late 1988. The new concentration could be as low as
0.62 mg/L, as opposed to the current MCL of 0.05 mg/L. The
proposal would be based on revised determinations of what
concentrations of arsenic present art unacceptable risk to public
health in ground water. Should this MCL be promulgated prior to
finalization of the ROD it will be considered relevant.and
appropriate to the Libby site, and the arsenic ground water
cleanup criterion will be the'new MCL.
A change in the MCL for tetrachloroethylene is anticipated
to be proposed in late 1988. The new concentration could be as
low as 0.005 mg/L. Should this MCL be promulgated in final form
prior to finalization of the ROD it will be considered relevant
and appropriate to the Libby site, and the tetrachlorcethylene
53
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Table 13
Appicable or Relevant
and Appropriate Requirements
Scis/Source Areas Action
'The following requirements have been identified as
applicable or relevant and appropriate to the response action
selected for clean up of contaminated soils and sources areas on
the Libby site. Specific citations for United States and State of
Montana statutes and regulations are provided, along with a
distinction between "applicable" and "relevant and appropriate."
In some instances, comments are provided for further information.
These ARARs have been identified on the basis of preliminary design
criteria for the selected alternative, land treatment with a liner.
Final remedial design may reveal other response action ARARs which
should be taken into consideration for remedial action. The site
administrative record contains extensive documentation on ARARs,
it should be reviewed for more insight into the identification
selection process.
Statute or
Regulation/Citation
Executive ^Drder 11990
40 CFR^Part 6
Clean Water Act, Section
404, 40; CFR Parts
230 & |31
Enda/igered Species Act
50 CFR;;Parts 200
& 402 ;:;
Resource Conservation &
Recovery Act,
40 CFR">art 264,
Subparts F, G, K,
L, M V:N
40 CFR 264.111
40 CFR Part 268 &
RCRA Section 3004
Applicable or
Relevant and Appropriate
Applicable
Applicable
Applicable
Conunent
Applicable and Relevant
and Appropriate
Old and New
Units
Applicable
-------
-i*e 1 3 Continued
Statute or
Regulation/Citation
Occupational Safety and
Health Act
29 CFR 1926, Sub-
Part P, and 1910
«
Ambient Air Quality
ARM 16.8.807, 809,
811, 814-822
Prevention of Significant
Deterioration of Air
Quality
ARM 16.8.925, 933,
928, 931,
Visibility Impact
Assessment
ARM 16.8.1003, 1004,
1007, & 1008
Air Quality Permit
ARM 16.8.1105
Emissions Standards
I ARM 16.8.1427
General Air Quality
J MCA 75-2-102, 201
Ron-Game and Endangered
^ Species
ARM 12.5.201
• MCA 87'-5-501
Historical Preservation
:J ARM 12.8.501
ARM 12.8.505, 506
507, 508
MCA 22-3-433, 435
Applicable or
Relevant and Approp r i a te
Comment
Applicable
Applicable
Applicable
Relevant and Appropriate
Applicable
Applicable
Applicable
Applicable
Applicable
Only Substantive
Requirements
Policy Statement
Policy Statement
Relevant and Appropriate Policy Statement
Applicable
Applicable
-------
Tabte 18 Continued
Statute or
Regulation/Citation
Solid and Hazardous
Waste Management
16.14.505, 520,
ARM 16.42.101, 102
ARM 16.44.106, 107
112, 113, 124
ARM 16.44.303, 310,
311, 321, 322, 323,
324, 330, 333, 416,
511, 512, 702
hazardous Waste Act
™ MCA 75-10-101, 1 02
and 202
MCA 75-10-212, 214
MCA 75-10-402, 414,
416, 601, 711
Applicable or
Relevant and Appropriate Comment
Applicable
Applicable
Applicable
Only Substantive
Requirements
Applicable
Relevant and Appropriate Policy statement
Applicable
Relevant and Appropriate Policy statement
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Table 19
Appicatie or Relevant
and Appropriate Requirements for
Upper and Lower Aqufers
The'following requirements have been identified as applicable or
relevant and appropriate to the response action selected for
clean up of contaminated ground vater in the upper and lower
aquifers. Specific citations for United States and State of
Montana statutes and regulations are provided along with a
distinction between "applicable" or "relevant and appropriate."
In some instances, comments are provided for further information.
These ARARs have been identified on the basis of preliminary
design criteria for the selected alternative for the upper
aquifer, in-situ bioremediation. Final remedial design may
reveal other response action ARARs which should be taken into
consideration for remedial action. ARARs for lower aquifer clean
R should be the same as for the upper aquifer, and they are
eluded here in order to establish the ARAR waiver
cumentation. The site administrative record contains extensive
documentation on ARARs, and it should be reviewed for more
insight into the identification and selection process.
Statute or Applicable or
Regulation/Citation Relevant and Appropriate Comment
Executive Order 11990
40 CFR Part 6 Applicable
Clean Water Act, Section
40,4, 40 CFR Parts
230 & 231 Applicable
. •
Endangered Species Act
50 CFR Parts 200
and 402 Applicable
Safe Drinking Water Act
40 CFR Part 141 Relevant and Appropriate
Underground Injection
•ontrol Act
^40 CFR Part 144 Relevant and Appropriate
-------
19 Continued
Statute or
Regulation/Citation
Occupational Safety and
Health Act
29 'CFR 1926 Sub-
Part P and 1910
Resource Conservation
and Recovery Act
40 CFR 264, Sub-
Part J
Nondegradation of
Water Quality
ARM 16.20.702
ARM 16.20.703
Pollution Discharge
Elimination System
ARM 16.20.916
Ground Water Pollution
Control System
ARM 16.20.1002,
1003, 1010, 1011
ARM 16.20.1013,
1015, 1016
Public Water Supplies
ARM 16.20.201
»
ARM 16.20.203, 204,
205 and 207
MCA 75-6-101
MCA 75-6-112
Water Well Standards
ARM 36.21.635, 638,
640-662, 664-679
Applicable or
Relevant and Appropri_ate
Comment
Applicable
Applicable and
Relevant and Appropriate
Applicable
Relevant and Appropriate
Applicable
Applicable
Applicable
Relevant and Appropriate
Relevant and Appropriate
Relevant and Appropriate
Relevant and Appropriate
Applicable
Old & New Tanks
Only Substantive
Requirements
Only Substantive
Requirements
Only Substantive
Requirements
Only Substantive
Requirements
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Table 19 Continued
Statute or
Regulation/Citation
Water Use
ARM 36.12.103
«
MCA 85-2-101
MCA 85-2-301
MCA 85-2-306
MCA 85-2-317
MCA 85-2-401 thru
418
MCA 85-2-505, 506,
md 507
Solid and Hazardous
Waste Management
ARM 16.44.335
Non-Game and Endangered
Species
ARM 12.5.201
MCA 87-5-501
Historical Preservation
ARM 12.8.501
»
ARM 12.8.505, 506
Applicable or
Relevant and Appropriate
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Relevant and Appropriate
Applicable
Comment
Policy statement
Only Substantive
Requirements
Only Substantive
Requirements
Policy Statement
Policy Statement
-------
ground water cleanup criterion will be the new MCL.
A change in the MCL for pentachlorophenol is anticipated to
be proposed in late 1988. The new concentration could be as low
as 0.2 mg/L. Should this MCL be promulgated in final form prior
to finalization of the ROD it will be considered relevant and
appropriate to the Libby site, and the penta ground water cleanup
criterion will be the new MCL. Also, the recent reclassification
of penta as a probable human carcinogen (see discussion below)
could, lower the new MCL to a much lower concentration.
It is anticipated that another change involving
pentachlorophenol could have significant impact upon the site
cleanup requirements. Penta has been considered by EPA as a
Class D carcinogen, meaning that there are no carcinogenic
effects associated with the compound. Recent studies have caused
EPA to re-evaluate that stance, and penta has been reclassified
as a B2, probable human carcinogen, based upon evidence of
carcinogenicity in animals. This determination will require
publication of carcinogenic potency factors for the compound
which have previously not been used. Risks associated with penta
for the Libby site has been based primarily on non-carcinogenic
Affects. The availability of carcinogenic potency factors for
Biis compound may have significant impact upon cleanup criteria,
^Thich have been based to date on land disposal restrictions BOAT
(soils) and a health advisory for ground water. Should potency
factors be published prior to finalization of this remedy
selection document, new risk calculations will be conducted and
cleanup levels may be revised.
Potency factors under consideration by EPA have been
reviewed by Libby project personnel. A range of potency factors
has been prepared, the value of which is dependent upon the type
of pentachlorophenol found on site. Comparison of these potency
factors to the potency factors used in Libby risk,assessment
suggests that the 37.00 mg/kg BOAT treatment requirement will
pr.ovide a protective cleanup level within the acceptable range of
risk.
. •
Cost Effectiveness
The selected remedial alternatives are cost effective
options for Libby site cleanup. This determination is based on
the cost and overall effectiveness of the selected remedies when
viewed in light of the cost and overall effectiveness of other
alternatives.
For soils and source areas cleanup, enhanced bioremediation
-and land treatment (alternative 5A( 1 )) is more costly than land
treatment without a liner and capping, but less costly than other
treatment alternatives. This alternative will degrade
contaminant concentrations to acceptable levels which are
59
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protective of human health. land treatment with a liner may
provide a substantial amount of greater environmental protection
than land treatment without a liner. The only alternative which
will achieve greater treatment efficiencies is incineration.
Incineration will reduce organic concentrations lower than land
treatment, but there will still be potentially hazardous ash
products to dispose and cap on site. Land treatment with a liner
is considered to be the most cost effective remedy.
. In-situ biodegradation of the upper aquifer is the least
costly'treatment alternative. In-situ biorestoration will
effectively degrade contaminant concentrations to acceptable
levels in a relatively short time frame. It is considered a more
effective, more permanent remedy than either pump and treat
alternative, because degradation of contaminants in the ground
water and contaminants adsorbed onto aquifer matrices will occur
simultaneously. In-situ biodegradation is considered to clearly
be the most cost effective remedy.
A cost effectiveness evaluation of the final remedies
evaluated for remediation of the lower aquifer cannot be
completed. As stated, the preference to conduct a field test of
in-situ biodegradation potential as an interim remedy will allow
collection of needed data to make comparisons. Oil recovery
alone, and treatment of oils and ground water in the lower
aquifer, would clearly be a cost-intensive process with limited
effectiveness. If in-situ biodegradation proves to be
technically practicable in the lower aquifer it is believed by
EPA that it will also be a much more cost effective alternative
than any other proposed to date for this sub-action.
Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the Maximum
Extent Practicable, and the Preference for Treatment as a
Principal Element of Selected Remedies
The selected remedies satisfy the statutory preference for
utilization of permanent solutions and alternative treatment
technologies. Treatment is a principal element of the
alternatives selected for all sub-actions. The remedies selected
for cleanup of soils/source areas and the upper aquifer will
treat contaminant concentrations to acceptable health based
levels. They are permanent solutions in that they will destroy
contaminant concentrations, not merely transfer pollutants to
another media for eventual disposal. Enhanced bioremediation of
the soils area is considered an innovative technology when
utilized in the approach discussed in this document. A
combination of land treatment with in-situ, source area
degradation in the saturated zone of the waste pit will
effectively reduce all potential contaminant exposure routes
permanently.
60
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In-situ biorestoration, of the upper aquifer is considered in
innovative approach to ground water remediation which has covious
implications for sites across the country. The alternative
presented in this remedy selection will permanently destroy
contaminant conce- '.rations in place, without having to perform
intensive pump an^ treatment actions. Additionally, the in-situ
program is expected to be much more effective, in a shorter
timeframe, than traditional pump and treatment scenarios.
Finally, whereas pump and treat ground water extraction systems
hav;em been hampered by an inability to extract contaminants
adsorbed onto particle surfaces and in micropores, the in-situ
biodegradation process will work concurrently on all areas of
contamination within the aquifer.
It is hoped that an in-situ biorestoration program for the
lower aquifer will prove to be effective as well. However, the
types of contamination (product pools and aqueous phase) found in
the lower aquifer suggest that active biodegradation will be much
more difficult to initiate. It should be recognized that other
treatment alternatives, such as the oil recovery systems based on
oil reservoir technology, would have only limited effectiveness
at the Libby site. The high cost of implementation, the low
effectiveness and the extremely long time frame required to
achieve desired cleanup levels make oil recovery an impracticable
alternative. In-situ biorestoration, alone or in conjunction
with other technologies considered, is the only potential cleanup
alternative which EPA has been able to identify worth pursuing.
61
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References
Administrative Order on Consent, October, 1335, 'J. S.
Environmental Protection Agency and Champion International
Corporation
' :phase IV, Step 3 Remedial Investigation Report, Libby,
Montana Ground Water Contamination Site, April, 1938,
Woodward-Clyde Consultantsfor Champion International
Corportion
Potentially Responsible Parties Search for Libby Ground
Water Site: Title Search, February, 1988, TES IV Contract
168-01-7351, Work Assignment 1404, Jacobs Engineering Group,
Inc. 'for U.S. EPA
Public Reviev Draft Feasibility Study for Site Remediation.
Libby, Montana, November, 1988, Woodward-Clyde Consultants
for Champion International Corporation
Potential for Migration of Hazardous Wood Treating Chemicals
during Land Treatment Operations, July, 1987, Technical
Completion Report, Project G1234-03, Gary D. McGinnis
6. Feasibility Study for the First Operable Unit, Libby,
Montana, Ground Water Contamination Site, July, '986,
Woodward-Clyde Consultants for Champion International
Corporation
7. Superfund Public Health Evaluation Manual, October, 1986,
EPA 5401-1/86/060, Office of Emergency and Remedial
Response, U.S. 'EPA
8. .. Bioremediation of Contamination by Heavy Organics at a Wood
Preserving Plant Site, November, 1987, in Proceedings of
•Superfund '87, Hazardous Materials Control Research
Institute
9. Paradise Land Treatment Facility, RCRA Part 3 Permit
Applicaqtion, 1987, Remediation Technologies for Burlington
Northern Railroad
1o. Land Treatment Demonstration Summary Study and Discussion:
Characterization/Treatability Study Report, 1986, Koppers
Company, Inc., for U.S. EPA
1 1 . Creosote, Inorganic Arsenicals, Pentachlorcpher.ol - Position
Document No. 2/3, U.S. EPA, January, 1981
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IJttoy Ground Water Site
Responsiveness Summary
Attachment A
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Responsiveness Summary
for the
IJbby Ground Water Site
LJbby, Montana
: The U.S. Environmental Protection Agency (EPA) and Montana
Department of Health and Environmental Sciences (MDHES) held a
public comment period, on the Proposed Plan and Feasibility Study
Report for the Libby site, from November 11 through December 12,
1988. Both the Proposed Plan and the FS report were made available
to the public for the entirety of the public comment period. In
addition, the administrative record for the site was available for
review in the County Sanitarian's Office (the information
repository) in Libby during the public comment period. A public
meeting was held in Libby on November 29th to discuss the Proposed
Plan and FS Report, and other site issues, with concerned citizens
and public officials. This Responsiveness Summary has been
prepared to document questions or concerns raised by persons at the
public meeting and provide EPA's responses. Written comments
Kceived during the public comment period are also responded to in
^his document.
The public meeting was held at the Lincoln County Annex
Building in Libby, Montana, on November 29, 1988 from 7:00 p.m. to
approximately 9:30 p.m. Those attending the meeting included
representatives from EPA, MDHES, Champion International Corporation
and it's project consulting firm, Woodward-Clyde Associates,
members of the Lincoln County Board of Health, other city, county
and state public officials, news media representatives, and
citizens of Libby and/or Lincoln County. Also, a Court Reporter
and Notary Public of the State of Montana reported the proceedings
of the meeting in a stenographic transcript, available for review
in the site administrative record.
*
An ^agenda was prepared for the meeting and provided to
attendee's, along with a copy of the Proposed Plan and a meeting
briefing package for later reference. EPA, MDHES and Champion
presented a review of the Superfund regulatory authorities, a brief
history of the site, an explanation of the results of the
Feasibility Study, a review of the alternatives evaluation results,
description of the detailed alternatives, and information on the
remedy selection process. Questions were answered throughout the
meeting. No specific comments were made during a separate public
Ifcomment period at the end of the meeting.
-------
History of Commurrty Relations Activities
Contamination of ground water was first reported in Libby in
1979. At the time, many residents were apparently skeptical of the
analytical results for ground water samples, but residents became
more aware of the magnitude of the contamination problem after
stories were written in the local newspapers and public meetings
were held. During early testing of ground water wells, EPA and
State representatives met and discussed their activities with the
individual well owners. Many residents preferred to have Ron
Anderson, the Lincoln County Sanitarian, as a focal point for these
issues. EPA and the State have continued to rely on Mr. Anderson
for contact with the community, as have corporate and regional
representatives of St. Regis and Champion.
News releases and fact sheets have been issued in conjunction
with significant site activities. Local newspaper coverage was
more extensive during early site activities, prior to the first
Record of Decision for an alternate water supply. The following
community relations activities have been conducted:
o News releases and fact sheets issued in conjunction with
site nomination to the NPL.
o Phase I investigations results were sent by St. Regis to
each homeowner whose well was tested.
o Results of the Phase I investigations and the consent
decree process were presented to the public for review
and comment at the County Health Board's monthly meeting
on October 18, 1983.
o In April 1984, a fact sheet recommending limited water
use and well installation was included in the sewer bill
mailing.
o In July 1986, a fact sheet was sent to area residents
using the local newspaper as a distribution system.
i
o A public meeting was held on July 15, 1986 in the county
annex, to discuss alternatives for providing clean water
to local residents. This meeting initiated, a 30-day
public comment period.
o In January 1988, EPA and MDHES conducted community
interviews with residents and public officials of Libby
to gather information for revision of the Community
Relations Plan.
o A progress report was distributed to persons on the EPA
mailing list in June 1988, providing .an update as to site
activities.
-------
o On November 11, a public comment period was initiated to
address the draft Feasibility Study report and the
Proposed Plan for site clean up. The comment period
ended on December 12, 1988.
The remainder of the responsiveness summary will consist of
Agency responses to questions and/or comments raised during the
public comment period. The first portion will address questions
and/or.comments from the public meeting. Similar questions or
comments from the meeting are combined into one for the
responsiveness summary. Specific questions, comments and replies
made during the public meeting may be reviewed in the meeting
transcript. The second portion responds to a set of written
comments from a Libby resident received at the end of the public
comment period, and the last section consists of responses to
written comments submitted by Champion International Corporation
during the public comment period.
Pubfic Meeting Questions and Comments
Kestion: Some persons questioned the locations of the contaminant
urces. For instance, the butt dip tank area, tank farm area and
ste pit area were identified by EPA and MDHES (the Agencies) as
the prime contaminant source areas. However, some attendees
suggested that there may have been at least one more dump area.
Response: Extensive site-wide sampling at Libby has not revealed
other "source" locations. It is possible that the large source
area, the waste pit, is actually a combination of two different
dump sites, resulting in some confusion during the public meeting.
However, because of the possibility that there may still be other
waste locations on site not yet identified, EPA will conduct a
review of records concerning waste dumping and burning locations to
see if another source area has been inadvertently overlooked. The
EPA project manager will also make a site visit with persons
expressing this concern to try and pinpoint other potential dump
locations. Finally, the Record of Decision has been written to
allow fo,r clean up of any as yet unidentified source areas during
remedial action, but it is EPA's belief that all contaminant
sources have been located.
Question: Many questions were raised about the depth of excavation
to remove contaminated soils. Individuals expressed opinions that
this would not be deep enough to take care of the contamination
problem in the ground water. They recognized that oils and product
ave migrated down through time, and that there is probably a lot
f source material at depths much deeper than the water table.
Response: EPA agrees that excavation of soils to the water table,
and treatment of those soils, will not address a large portion of
the site contamination. Excavation of soils below the water table
-------
would require a difficult set of engineering controls to -depress
^ho water table in the area to allow excavation. Because of the
nrolific around water flow in the area further excavation would be
SIrv difficult and expensive. However, the selected remedies do
for the clean up of source materials in the saturated zones
?eet or so A rock percolation bed upgradient of the
t area will be used to filter treated water and oxygen and
' into the saturated zones to stimulate biodegradation of
ntaminants Ground water and oil extraction wells will be placed
"st£owngradient of the waste pit area to remove ree Pjoduct and
highly contaminated ground water. Ground water will be treated on
the surface and then reinjected through the rock percolation bed or
injection wells. The purpose of this process is to isolate the
high concentration source areas in the saturated zone from the rest
of the ground water system. This will greatly reduce contaminant
loading into the rest of the aquifer, and hopefully accelerate the
natural contaminant biodegradation processes.
Question: A few individuals expressed concerns about institutional
controls. Specifically, they suggested that controls such as the
City prohibition on well drilling are a violation of individual
property rights.
Response: The institutional controls considered for the site are
designed to protect human health and the environment. For
instance, the City prohibition on well drilling was passed because
Libby did not want any other persons potentially exposed to ground
water contamination. The other institutional controls under
consideration are for use of property on the Champion site. As an
example, one control might be used to prevent construction
activities on contaminated areas. This will reduce the potential
for human exposure to contamination. Finally, all institutional
controls are prepared under appropriate legal advice so as not to
violate individual rights.
Question: One person commented about the lack of response by EPA
to questions he raised a couple of years ago concerning cancers in
the Libby area which may be attributed to contaminated ground water
and.the .site.
Response: EPA .conducted some research into cancers in the Libby
area.This information is contained in the administrative record.
However, no conclusions were drawn from the research for a number
of reasons. First, documentation of cancers into a database has
only been conducted since the 1970s. Since wood treating
operations were carried out at the Libby site from 1946 to 1969, no
data is available to correlate cancers during contaminant use
periods. Also, there is a relatively small population of persons
which could be studied to determine cancers caused by ingestion of
contaminai :d drinking water. Many of those persons probably worked
at the Champion Plant, or other industrial locations, where
exposure to various substances may have occurred. Therefore, the
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identification of causes of cancer r.ay r.ct ce possible: In
summary, even if a higher than normal cancer frequency could be
determined for the near-site Libby population, it may be impossible
to isolate the factors behind such a trend.
Question: Many questions were raised about the extent of ground
water contamination. For instance, is there evidence of
contamination south of the plant? Is there contamination in the
ground water on the west side of Flower Creek? Some of these
questions were related to concern about why some residents were not
offered the buy-water plan for city water.
Response: These questions were answered explicitly during the
public meeting using maps to reflect contamination extent. In
summary, there is no evidence of ground water contamination south
of the plant because of the very strong ground water flow to the
north and northwest of the site. Contaminants have not been
detected in ground water west of Flower Creek. Concentrations in
wells near the Creek on the east side have always been extremely
low, and often not detectable. If contaminant plumes were to
migrate that far, EPA believes Flower Creek would act as a flow
barrier, and contaminated ground water would either be discharged
into the Creek or redirected along the flow of the Creek toward the
^ootenai River. However, contaminant plumes do not appear to be
migrating, based on extensive samplings conducted over the past few
years. Natural organic degradation and contaminant adsorption onto
matrix .surfaces may have effectively halted any further migration.
Finally, residents with private wells outside the area of ground
water contamination were not offered "free" city water because they
had no known exposure to the contamination. If plumes migrate in
the future, and contaminate more wells, residents using those wells
will be offered an alternate water supply under the buy-water plan
under the provisions of the Record of Decision.
Question: Would pumping wells installed on site as part of the
clean up program have any effect on private wells located near the
plant?
t
Response: The large volumes of flow in the upper aquifer would
preclude any impact on residential wells from the extraction wells
considered in the FS report.
Question: What happens to the bacteria after it is done clean-ing
the contaminants from the ground water?
Response: The bacterial populations in question will be large as
long as there are contaminants in the ground water. After
Contamination has been destroyed, the bacterial populations will
rapidly decrease because of the lack of a food source.
Question: What will prevent contaminants from leaching into the
water during treatment or in un-capped areas?
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Response: Some leaching of contamination may occur in the waste
pit area during treatment. However, the ground water extraction
and injection system discussed in a previous response will prevent
the leaching from being a problem. There should be no contaminant
leaching in the land treatment cell because there will be a bottom
liner providing a barrier to contaminant migration. There should
b« no areas with significant residual contamination that are not
capped at the end of excavation and/or treatment.
Question: How long will it take to clean the aquifer?
Response: Preliminary modeling conducted for the FS report
indicates the aquifer could be remediated in as little as five
years. However, an estimate at this stage is relatively
speculative.
Question: What effect would flooding, or high water recharge
rates, have on land farming, and could it also alter the direction
or speed of ground water flow?
Response: The land treatment unit will be placed in an area higher
than the 100 year flood plain, making it unlikely that flooding or
rain will impact the treatment area. Also, engineering controls
will be used to keep the unit from being flooded. Large amounts of
rain can raise the water table in the aquifer, but heavy recharge
would probably have little impact on the direction and rate of
ground water flow, other than short term effects. Variable ground
water levels can have an effect on contaminant distribution within
the system, but we have not been able to make such a correlation in
Libby.
Question: Isn't there a contamination problem resulting from water
washing over treated logs?
Response: It is probable that logs treated with chemicals lose
spme material onto the ground, through drippage and rain
solubilization. This can cause contamination problems, and
probably has in the past at Libby. However, there is no wood
treating going on at Libby now so the logs stacked outside in the
yard are not releasing wood treating contaminants.
Question: Will there be monitoring of ground water down gradient
of the area where soils will be treated, to detect contaminant
leaching?
Response: Yes. Monitoring of ground water using monitoring wells
and soil-pore water using lysimeters will be conducted up gradient
of, down gradient of, and within the waste treatment areas.
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Question : What dees the 35.75 rating in the historical s'xatch
mean?
Response: That number, a product of the early site investigation,
reflects a numerical score given the Libby site to assess how much
of a threat to human health and the environment it was causing.
Sites which received a score of 28.5 or over are eligible for
placement on the National Priorities List of hazardous waste sites.
Written Comments - IJbby Resident
*
What assurance is there that the buy-water plan will be continued?
The buy-water plan, as noted by the commenter, is funded by
Champion International. However, implementation of the buy-water
plan was authorized by EPA in the Record of Decision for the First
Operable Unit, signed September, 1986. This decision and the
current Record of Decision mean that EPA will assure that the buy-
water plan will be continued as long as there is a threat to human
health via ingestion of well water. This will be required of
Champion in the consent decree which is expected to be entered
concerning this ROD.
Pnat are the plans to take care of other areas (re: buy-water plan)
if contamination should spread?
The 1986 Record of Decision and this Record of Decision also
addressed this concern. If contamination in the aquifer should
spread outside of the areas currently identified, the buy-water
plan will be extended to all newly impacted well owners and users.
In fact, additional persons have been added to the buy-water plan
since implementation. Alternative water supplies will be provided
to anyone being impacted by the contaminant plumes, whether they
reside within the city limits or not.
There are at least 3 springs west of Libby that have not been
monitored in any way.
t
EPA has f not sampled the springs west of town. However, private
wells and monitoring wells between the springs and the known extent
of ground water contamination have been checked on a periodic
basis. As long as these wells are free of contamination the
springs should also be free of contamination emanating from the
Champion plant.
The wastes must go much deeper than 15 feet, the depth of
xcavation. The excavation should go much deeper to get a thorough
of the amounts of contamination.
This comment was addressed in response to questions raised during
the public meeting on previous pages. EPA believes that there is
sufficient information to warrant making a clean up determination
-------
for the scarce areas. The problems vith excavat i.-.-g -deeper than -.ha
water table were previously addressed.
Re: City or County ordinance prohibiting well drilling - Is this
not talcing away part of your property value and rights?
The ordinance prohibiting well drilling in Libby is believed to be
within the legal discretion of the City. It is worth remembering
that the purpose of the ordinance is to prevent additional human
exposu.re to potentially harmful chemicals in the ground water. A
courrtiy ordinance would also be enacted, if required. With regard
to property value, EPA is not aware of any impact this ordinance
has had upon property values in Libby.
Placement of a cap over areas to reduce water infiltration is a
waste of time, considering ground water will continue to spread
contaminants.
EPA believes that the caps placed over excavation and treatment
areas will accomplish two things. First, they will reduce the
potential for further contaminant loading to the aquifers by
reducing water infiltration and contaminant leaching. Second, and
more importantly, the caps will provide an additional protective
measure against direct human exposure to residual contamination.
At what point will EPA funds step in if Champion does not pay for
the remedy or stops funding the remedy?
This Record of Decision authorizes EPA to carry out the preferred
remedial alternatives selected, regardless of who pays for the
clean ups. Champion International Corporation, as the responsible
party for the Libby site, has expressed a strong desire to continue
to pay for and conduct the response actions at the Libby site. EPA
does not anticipate that Champion will change its decision, based
on Champion's input to the administrative record for the site.
However, if responsible party refuses to carry out the selected
remedial action, one of EPA's options is to use money from the
Super fund Trust Fund to pay for site clean up.
Written Comments - Champion International Corporation
Champion International Corporation provided written comments
to the Proposed Plan. These comments were based on the information
in the Proposed Plan and information given by EPA and MDHES at the
public meeting. Champion's comments are directed at four main
areas: Ground water clean up levels. Soil clean up levels,
Compliance with applicable or relevant and appropriate requirements
of the land disposal restrictions (Land Ban) and the Remedial
action plan for the lower aquifer. Champion's comments are
attached, followed by EPA responses to those comments.
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-..... :,,
NUMBER ADMINISTRATIVE RECORD v" :Y
0EC 0 S ''388
-2SCUNO *ATER CLEAN UP LEVELS
MGH7AW GF'iCE
EPA's proposed ground water clean up level Indicated at the public meeting
on November 29, 1938 included:
Pentachlorophenol - 0.2 aig/1
Total PAH - 0.4 ug/l
Total suspected carcinogenic PAH 0.04 ug/l
Currently there is no final MCI for pentachlorophenol and no ARAR require-
ment exists for this compound. Thus, the pentachlorophenol cleanup level
must be risk-based. The pentachlorophenol cleanup level should be based on
potential fetotoxic effects and established at the lifetime Health Advisory
Level of 1.05 mg/1 (Table 4-4 of Feasibility Study).
To date, appropriate scientific rationale has not been provided by the EPA
for the total PAH compound cleanup level of 0.4 ug/1. Other than for the
suspected carcinogenic PAH compounds, (addressed separately and discussed
below) there is no evidence provided by the EPA for PAH compound risk to
humans or the environment. Champion has not been provided with any risk
evaluation supporting this cleanup level. Therefore, Champion proposes
that this cleanup level be dropped.
No MCL exists for PAH compounds and thus there is no ARAR for use in
establishing cleanup levels. Based on a literature study, a list of
suspected carcinogenic PAH compounds (fluoranthene through
inde'no(123, cd)pyrene) were identified for this site. However, there are
no individual carcinogenic potency factors for this list of PAH compounds.
The benzo(a)pyrene potency factor is assumed for ' all compounds.
Benzo(a)pyrene (BaP) is believed to represent the most toxic compound in
this group. However, due to the very low mobility of BaP in the ground
water, BaP and other heavier PAH compounds are not found, or projected to
be found in the off-site ground water at Libby. Thus, the estimated
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21990 (21990ins«r 12-07-88) (§2P-CHA)
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carcinogenic risk ".ave.s for ?AH compounds presented in ::-.e o ir? n'jh'y
conservative (page 4-24 of FS).
The conservative estimation of PAH compound carcinogenic risk (based on 8aP
toxldty) results in a further problem: the reliable measurement of PAH
compounds at sub-part-per-trillion (ng/1) levels. The practical analytical
=detection limit for most carcinogenic PAH compounds is around 0.1 ug/1 for
%
each compound. Pilot demonstrations of the proposed remedial technology,
in-situ bioremediation, have Indicated that cleanup to the practical
analytical detection limit may be achieved at this site. However, cleanup
to lower levels, such as EPA's proposed 0.04 ug/1, has not been
demonstrated.
Since EPA's proposed 0.04 ug/l cleanup level is below the practical
analytical detection limit and has not been demonstrated to be met by the
proposed technology, Champion proposed an interim cleanup target of
0.1 ug/1 for each suspected carcinogenic PAH compound (page 4-24 of FS).
Champion further proposed that this interim level be reevaluated when it is
shown that ground water remediation is approaching this target. A final
cleanup level would then be set which is protective of human health and the
environment, considering appropriate technological limitations (in
accordance with CERCLA requirements) and updated toxicological data
concerning the appropriate PAH compounds' carcinogenic potency. EPA is
currently developing PAH compound potency factors for compounds other than
BaP.
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21990 (21990inser 12-07-88) («2P-CHA)
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SOIL CLEANUP LEVELS -
At the FS public meeting on November 29, 1988 the EPA proposed son cleanup
levels, Including the following:
Pentachlorophenol - 36.75 uig/kg
Total Suspected Carcinogenic PAHs - 88 mg/kg
EPA's proposed pentachlorophenol cleanup level 1s apparently based on the
August 17, 1988 Federal Register land disposal restriction regulations and
K001 nonwastewater treatment standards. This 1s not a risk-based cleanup
level, but 1t 1s an ARAR. Compliance with this ARAR 1s addressed in a
separate attachment to this letter, Compliance with the Land Ban ARAR."
As indicated by the discussion in that attachment, the land ban ARAR
schedule for meeting the K001 nonwastewater treatment standards is not in
effect until August 8, 1990. Thus, establishment now of a
pentachlorophenol cleanup level, which 1s not risk-based, 1s not justified.
In the Feasibility Study Champion proposed a cleanup level of 100 rug/kg
instead of EPA's proposed cleanup level of 88 mg/kg. EPA's proposed soil
cleanup level for suspected carcinogenic PAH compounds is based on the
assumed exposure to a construction worker. A number of assumptions are
needed to establish a scenario whereby a construction worker could be
exposed to contaminated soil, especially soil that has been land treated,
covered and fenced at closure. These assumptions produce considerable
uncertainty in the risk estimates for this exposure scenario. For example,
to arrive at the 38 mg/kg cleanup level, it was assumed that the construc-
tion worker ingests 480 mg (1/20 of a teaspoon) of contaminated soil per
day. If the ingested amount were 413 mg/day (1/25 of a teaspoon) the
estimated cleanup level would be 100 mg/kg for suspected carcinogenic PAH
compounds. Similarly, a 4 month (17.3 week) exposure period was assumed
for the construction worker scenario. However, if the exposure period
assumption was set at a 3.4 month (14.9 week) period the estimated cleanup
level would again be 100 mg/kg.
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21990 (21990ins«r '2-07-88) (*2P-CHA)
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These examples indicate the uncertainty In the risk estimates, .ir.o :-e
Importance of considering the effect of assumptions 1n evaluating risk.
This 1s especially true since there is no standard set of assumptions for
the exposure scenarios developed for soil. Thus, we do not believe it is
appropriate to select a number that results from a preselected exposure
model without considering other relevant factors Including the assumptions,
tlje-1r Influence on the estimate, and thus, the degree of confidence 1n the
estimate. As 1s illustrated above for the construction worker exposure
scenario, we have no reason to believe that the exposure dosage and
exposure duration are exact. Thus, the risk estimate should not be treated
as exact.
As Indicated in the FS (page 4-29) the preferred remedial alternative (land
treatment) will provide additional exposure controls (i.e., clean cover,
deed restrictions, access control and security) which are not explicitly
treated 1n the risk assessment model. Given the added protection provided
by an engineered land treatment facility, we believe a cleanup level which
is rounded up from 88 rag/kg to 100 mg/kg is justified. We also believe
that 100 mg/kg better reflects the uncertainty in the estimate, by setting
an order of magnitude value.
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21990 (21990inser 12-07-38) («2P-CHA)
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COMPLIANCE WITH THE LAND 3AM A2AR
Section 4.5 of the Feasibility Study (page 4-15) addresses the requirements
for compliance with land disposal ban at the Libby site. However, based on
recent conversations with the EPA and the EPA's proposed pentachlorophenol
cleanup level for soil (discussed earlier), 1t 1s unclear to Champion how
: EJ'A presently views compliance with the land ban. Below we present our
interpretation of the August 17, 1988 Federal Register land disposal
restrictions.
The land disposal restrictions for K001 wastes is an ARAR far the Libby
site. The effective land ban date for K001 soil and debris is
August 8, 1990. As EPA discusses 1n the Rule publication, a policy
decision was made to extend the effective dates of this Rule for
contaminated soil and debris. Thus, the land ban ARAR has been established
for the Libby site, but treatment standards for K001 nonwastewater (page
4-18 of FS) are not required to be met during land treatment until after
August 7, 1990. Starting on August 8, 1990, and unless the land ban
requirements are waived by the EPA, operation of the land treatment unit
must demonstrate treatment of the listed compounds for K001 nonwastewaters
to the treatment standards established by the rule.
If land treatment is the approved remedial action for soils at this site,
Champion plans to start full-scale operation of the land treatment unit
during the summer of 1989. Land treatment of contaminated soils may not be
completed by August 8, 1990. Thus, continued operation of the land
treatment unit past this effective date will require; 1) a demonstration
that the unit can achieve the K001 land ban treatment standards or 2} a
demonstration of no migration of contaminants from the unit. It is
Champion's plan to collect appropriate data for these demonstrations during
operation of the land treatment unit 1n the 1989 and/or 1990 treatment
seasons. However, data collected in 1988 from a pilot demonstration unit
indicated that achieving the K001 treatment standard may not be feasible.
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21990 (21990inser 12-07-88) (•2P-CHA)
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i 'J ! ... J i •-
If this 1s found to be the case, the demonstration of no-algration *culd be
relied upon by Champion for continued operation of the land treatment unit.
A successful demonstration of no migration of contaminants for a K001 waste
would exempt the waste from restrictions Imposed by 40 CFR Subpart 268
(land ban). The no migration demonstration criteria address the specific
: waste and operations of concern, and 1s not a waiver for selected contami-
nants nor can 1t be applied to a different operation or site. Thus, if a
waiver 1s granted for the Ubby site, it would apply to the waste material
addressed in the L1bby demonstration, and exempt land treatment of this
waste from the land disposal ban requirements.
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21990 (21990inser 12-07-88) (»2P-CHA)
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LOWER AQUIFER REMEDIAL ACTION
In the EPA's Proposed Plan for the Ubby Ground Water Site, a two-year test
of 1n-s1tu bloremediation was proposed for the lower aquifer to determine
1f such a technology 1s effective, and implement It, if found to be effec-
tive. The potential effectiveness of the 1n-s1tu b1oremed1at1on technology
was addressed extensively 1n Appendix F of the Feasibility Study (FS) and
'summarized 1n Section 5.0. Based on this evaluation, we do not believe
that there 1s any technical basis for preselection of this technology as
the remedial action for the lower aquifer. To date, no technical or cost
information supporting EPA's proposal for selection of this technology for
the lower aquifer has been provided to Champion or reviewed by Champion 1n
the Administrative Record. This technology has not been selected 1n any
other ROD nor employed at another site and thus is not technically
supported. Below we summarize our findings regarding the application of
in-s1tu bioremediatlon to the Lower Aquifer (Operable Unit C) at the Libby
site.
Use of the in-situ biodegradation technology for dissolved phase contami-
nant remediation has potential for success, as demonstrated for the upper
aquifer. However, the application and potential for success of in-situ
biodegradation is significantly different for the degradation of the free
phase oil within the lower aquifer. The reasons that the remediation
potential is low for the lower aquifer are: 1) the high PCftconcentrations
in the oil severely retard the oil degradation, 2) degradation of the oil
only occurs at the oil-water interface, thus significantly slowing the
degradation rate, 3) the injected water, oxygen and nutrients would tend to
flow over the oil phase where the permeability 1s higher, thus the injected
solution will not efficiently disperse or enhance biodegraditlon in the oil
phase, and 4) the complicated stratigraphy and the occurrence of the oil in
many separate reservoirs would make 1t difficult to direct the oxygen and
nutrients efficiently to degrade an oil pool.
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21990 (21990inser 12-07-83) (•2P-CM)
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Because of the above listed prcolems, the use of 1n-sHu blodegradat'.on in
the lower aquifer to degrade the dissolved phase could be successful only
1n the near term. Unless continued for an extended period of time, 1t
would not remediate the lower aquifer contamination, because as soon as
water, oxygen and nutrient Injection were discontinued, the contamination
levels 1n the lower aquifer would rise due to the dissolution of the free
pil phase which constitutes the majority of the contaminant problem. It 1s
estimated that under the best conditions 1t would take at least 200 years
for the aquifer to dissolve the oil. Thus, the use of in-situ biodegrada-
tlon for long-term, permanent remediation of either the free oil phase or
the dissolved contamination 1n the lower aquifer 1s not considered to be a
feasible clean-up technique.
Because of the inability of the in-situ b1oremed1at1on technology to effec-
tively remediate the lower aquifer in the near-term, 1t 1s not reasonable
to expect that a two year test will provide useful data regarding its
effectiveness. During such a short period, dissolved contamination may be
reduced without any substantial degradation of pooled oil (the major
contaminant source). Thus, results could erroneously demonstrate some
effectiveness while not addressing the majority of the contamination.
Overall, the potential for failure of the proposed test is high and a time
frame of 2 years makes failure that much more likely.
•'>>
The Monitoring Alternative (Alternative 2c) should} be selected to evaluate,
over the next 5 years, the potential for oil migration and contaminant
recharge to the Kootenai River. This monitoring: program will establish a
better understanding of potential risks, if any, posed by leaving the
contaminants in place. Currently, there 1s no ^evidence that the oil is
migrating 1n the lower aquifer and there 1s no present use of the ground
water from this zone.
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21990 <21990ins«r 12^37-38) («2P-CHA)
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Response to Champion Comments
on the Proposed Plan
The following responses have been prepared to address
concerns raised by Champion International Corporation over
various issues contained in, the Proposed Plan and discussed at
:the. public meeting on November 29, 1988. The responses are keyed
by page and paragraph to the comments indicated on the previous
pages.
Ground Water Clean Up Levels (pgs 1 & 2)
Para 1: EPA agrees with the first comment. The pentachlorophenol
clean up level is 1.05 mg/L because the MCL referred to (0.2
mg/L) is not yet proposed or final. EPA would also point out
that this determination was reflected during the presentation for
the proposed plan. A clean up of 0.2 mg/L would be selected only
if the MCL were proposed or finalized prior to ROD.
Para 2: EPA disagrees with Champion's contention that the clean
up level for non-carcinogenic PAH compounds, or total PAH, of 400
ng/L (nano-gram per liter) should be dropped. The concentration
selection is based on two primary factors. First, many compounds
contained in creosote, which have not been commonly analyzed for
at Libby, are suspected or known to be cancer-causing. These
include some of the heterocyclic nitrogen base compounds like
quinoline or benzocarbazoles, and the aromatic amines such as p-
and o-toluidine.1] A maximum level of total PAfls will provide
additional assurance that all creosote compounds are being
reduced to acceptable levels.
Another reason for setting a total PAH concentration limit
is based on evidence that many PAH compounds are capable of
promoting the carcinogenic activity of another cancer-causing
compound. As an example, the non-carcinogens fluoroanthene,
.pyrene, benzo(e)pyrene and benzo(g,h,i) perylene, when applied
simultaneously with the carcinogen benzo(a)pyrene, resulted in an
increase in.the total number of tumors when compared to only
benzo(a)pyrene application.
There are a number of known or suspected cancer-causing
chemicals found in ground water at the Libby site, including
arsenic species, benzene, tetrachloroethylene and various PAH
compounds. Pentachlorophenol has also recently been recognized
as a probable human carcinogen. Known or suspected carcinogenic
substances have been detected in most areas that non-carcinogenic
compounds have been detected (Figures 7.23, 7.24, and 7.25 of the
RI Report, April 1988). EPA bases its determination on this
issue on the fact that a conservative clean up level for non-
carcinogenic PAH compounds will reduce the potential of promotion
of cancers at the Libby site. This justification has also been
-------
used in RODs for other Superfund sites, most notably the 3N
Brainerd site and the Reilly Tar and Chemical Company site. It
is especially appropriate to have a conservative approach to
clean up of non-carcinogens at Libby since the clean up level for
carcinogenic compounds results in a 10~5 health risk.
From a technological perspective, the selected remedy for
clean up of the Libby ground water system should easily achieve
the clean up criteria set for non-carcinogenic PAHs because the
compounds most difficult to degrade, the higher molecular weight
PAHS',* also have lower clean up levels in most instances.
Therefore, if the clean up levels for carcinogenic PAHs are met,
the non-carcinogenic clean up levels will most likely be
achieved.
Para 3, 4, & 5: Para 3 is a description of the risk assessment
process used. Champion's opinion that the estimated carcinogenic
risk levels for PAH compounds in the FS are "highly conservative"
is not shared by EPA. The rationale for development of the risk
assessment in this fashion is well documented in the
administrative record.
Para 4 discusses measurement of PAH compounds at low (ng/L)
concentrations. Champion states that the practical analytical
detection limit for most carcinogenic compounds is around 100
ng/L for each compound. EPA does not argue that detection of PAH
compounds at the proposed clean up level, 40 ng/L, is not
achievable using standard analytical techniques. However, based
on a review of different laboratories, EPA has found that the 40
ng/L detection limit can be achieved currently using special
analytical and sampling techniques, and method modifications.
Also, the need for low detection limits and special
analytical techniques will not be required for some time at the
Libby site. Low detection limits will be required when clean up
proceeds to the stage that targeted compounds are not present in
concentrations greater than 1 part per billion. This stage will
probably not be reached for some years.
•
Finally, the selection of clean up level is based on
protection of human health and the environment. The clean up
level is not, as proposed in para 5, a floating target, which will
be finalized only when technological limits are determined.
Soil Clean Op Levels (pgs 3 & 4)
Para 1 : Pentachlorophenol clean up and treatment levels are
based on the BOAT treatment concentration for the compound as a
K001 waste. The clean up level is considered an ARAR determined
concentration. In order for soils and source area materials to
be placed in the land treatment unit, after August 8, 1990, the
ARAR concentration of 37.00 mg/kg must be achieved. If this
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concentration is not met then a demonstration of no migration
will be used to allow placement and further treatment of wastes
after the statutory deadline.
Para 2: EPA disagrees with Champion's rationale for selecting a
clean up level af 1 00 mg/kg rather than the risk determined
concentration for carcinogenic PAH compounds of 88 mg/kg.
Champion first addresses the uncertainties inherent in risJc
assessment. Examples are provided which show that with
modification of certain factors, such as soil ingestion rate, the
clean up level for a particular risk would change. EPA does not
disagree with this conclusion, but merely points out, consistent
with the Champion examples, that had higher ingestion rates or
longer exposure periods been used in the risk calculations, the
clean up level would have been reduced to below 88 mg/kg. This
extreme sensitivity to analytical assumptions only emphasizes the
need for conservative clean up levels.
Para 3: Champion again addresses the uncertainties in risk
analysis and uses this as a basis for arguing that risk estimates
should not be considered exact. EPA does not argue that risk
analysis is an exact science. However, the assumptions used to
levelop the risk analysis were selected to a large extent by
Champion, for reasons based on scientific merit. EPA had only
minor modifications to these assumptions. This communication is
contained in the administrative record. It has also been clear
throughout the development of the feasibility study report, and
the risk assessment, that EPA would select clean up levels based
on protectiveness evaluations and ARARs.
Para 4: Champion argues that the additional exposure controls
provided by the selected remedy help to justify a higher clean up
level for soils. EPA h;as taken the additional exposure controls
into consideration wheniselecting a clean up concentration which
represented a risk valvije of 10~^/ rather than 10~6. Were the
additional exposure controls not available for the remedy a lower
clean up concentration would have been required.
Compliance vith the Land Ban ARAR (pgs 5 & 6)
Champion is correct in stating that the requirements of the
land disposal ban regulations are applicable for certain
activities to be done at the Libby site, if the Record of
Decision (ROD) is implemented. The land ban regulations and the
application of those regulations to the site are explained below.
Section 3004 of the Resource Conservation and Recovery Act,
as amended, 42 U.S.C. Section 6904, establishes requirements for
the land disposal of hazardous wastes, known as the land ban or
land disposal regulations (LDR). Regulations implementing this
statute are found at 40 CFR Part 268. These restrictions
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prohibit the land disposal of specified RCRA hazardous wastes
beyond statutory dates established by Congress unless (1) the
wastes are treated to a level or method specified by EPA, or (2)
it can be demonstrated there will be no migration of hazardous
constituents from the land disposal unit for as long as the waste
remains hazardous, or (3) the waste is subject to an LOR
exemption or a variance.
For purposes of LDRs, land disposal is defined as any
placement of RCRA hazardous waste in or on the land, including
placement of wastes into a land treatment unit, such as is
proposed for the Libby site. Thus, the standards for KOOl listed
waste are applicable to waste which will be placed into the land
treatment unit at the Libby site. Compliance with these
requirements is measured at the point of waste entry, or
placement, into the land disposal unit.
RCRA hazardous waste K001 is found at the site. Standards
for KOOl waste were promulgated in 53 Fed.Reg. 31138, August 17,
1988, and are promulgated at 40 CFR Part 268. The rulemaking
establishes BOAT numbers for several PAH constituents and for
pentachloraphenol, found in KOOl waste. The rulemaking also
grants a two year capacity extension for soil contaminated with
K001 waste, such that land disposal of that waste does not have
to meet the BOAT standards until August 8, 1990.
Placement of waste into the final land treatment unit at the
Libby site will begin in 1989 and continue past August 8, 1990,
probably into the 1991 field season. This placement will not
violate the land-ban prior to August 8, 1990, but, because waste
contaminant levels are expected to be above BOAT numbers when
waste is transferred from the waste pit into the final treatment
unit, placement ^ill violate the land band requirements after
that date. f
Accordingly! the ROD calls for Champion to submit a no
migration petition and EPA to approve such petition prior to
August 8, 1990. The petition must meet the requirements set
forth in. 40 CFR ;Part 268.6, and follow appropriate guidance.
Initial review by EPA personnel, and a review of draft guidance,
indicate that the site is a likely candidate for a no migration
petition, because it provides for the destruction of the waste to
levels near the BOAT levels after treatment, and because post
treatment levels will provide for adequate protection of risfc.
Despite the expected no migration variance from the land ban
BOAT requirements, the BOAT number for pentachlorophenol was
selected as a relevant and appropriate requirement for end of
treatment levels. The BOAT number for pentachloraphenol
represents a judgment by EPA of acceptable levels of contamin-
ation to be left in land disposal units. Pilot study data
indicates that the BOAT number for pentachloaphenol can be met at
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the final treatment unit prior to closure of the unit. The
number is also expected to provide adequate protection of human
health, a concern since pentachlorophenol is now formally
recognized as a probable carcinogen. Therefore, in Xeeping with
the intent of the land ban requirements, the BOAT number for
pentachloraphenol was selected as an enforceable requirement
under section I2l(d) of CERCLA for the cleanup of Libby site
soils.
: ; .Champion is incorrect in statements which reflect its belief
that the land ban requirements apply only to end of treatment
requirements for land treatment units. As stated, the land ban
requirements apply to waste at the point of entry into any land
disposal unit, which includes land treatment units.
Lover Aquifer Remedial Action Plan (pgs 7 & 8)
Para 1: The evaluation of in-situ bioremediation presented by
Champion in Appendix F of the Feasibility Study Report is not
detailed or extensive enough to preclude further attempts to
determine aquifer remediation potential. There is simply not
enough information available to make such a recommendation. More
^formation is required concerning hydrostratigraphic controls,
Product locations, and extent of contamination vertically and
horizontally. The following replies-to specific comments are
provided.
Para 2: All of the discussion in this paragraph centers on the
difficulties presented by attempting biodegradation of
contaminants in a non-aqueous phase.' EPA agrees that the
degradation rates for product would be much slower, and thus more
cost- and time-intensive, than degradation of dissolved
contamination. However, this process is not envisioned for lab
and pilot testing, nor for aquifer remediation. Rather, a
combination of various technologies should be considered to
remediate the system. The first step would be to remove as much
product as necessary from the system using primary oil recovery
techniques. A potential second step is to disperse the remaining
oil. throughout the aquifer as much as possible. Steam injection
at depth could possibly be effective for this. Dispersal of oil
vould distribute contaminants throughout the aquifer matrix,
thereby creating much more surface area on which microbial
processes can occur. Also, an increase in temperature may
increase product solubility, and enhance degradation rates. EPA
recognizes that oil dispersion can potentially increase the
vertical and lateral extent of contamination, as pointed out in
Appendix F of the Feasibility Study report. This possibility
Pill have to be carefully analyzed during the remediation
evaluation stage.
Para 3: EPA agrees that aquifer remediation would have to
continue until clean up levels are achieved and there is no more
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source (product) releasing contamination into the dissolved
phase. However, estimates tor the time required to clean up the
aquifer using an approach similar to that described above have
not been conducted.
Para 4: EPA agrees that a time requirement should not be
established to carry out the studies necessary to make a final
analysis of aquifer remediation potential. The tvo year test
referenced in Champion comments and during the public meeting was
merely an estimate of the time which may be needed. Ho time
limitation is included in the ROD, although the time estimate is
still discussed for planning purposes.
Para 5: Monitoring of contaminant concentrations and movement in
the lower aquifer will be required during and after the study,
regardless of the results of the study.
As Champion notes, there is no present use of the ground
water from the lower aquifer. However, the lower aquifer is
designated a potential use system. This is the over-riding
reason why EPA will require that all possible avenues of aquifer
clean up be thoroughly evaluated before selecting an alternative
which prohibits use of the aquifer until it is clean by natural
processes.
FCD:December 21, 1 988:Wallace:kv:comment
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