United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R07-93/068
September 1993
x°/EPA Superfund
Record of Decision:
Sherwood Medical, NE
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RECORD OF DECISION
SHERWOOD MEDICAL COMPANY SITE
NORFOLK, NEBRASKA
PREPARED BY:
u.S. Environmental Protection Agency
R.egion VII.
Kansas City, Kansas
SEP'l'EMBER, 1993
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DECLARATION POR TIlE RECORD OP DECISION
SITE NAME AND LOCATION
Sherwood Medical Company Site
Norfolk, Nebraska
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action
for the Sherwood Medical Company Site in Norfolk, Nebraska chosen
in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by
the Superfund Amendments and Reauthorization Act of 1986 (SARA)
and the National Contingency Plan, 40 C.F.R. Part 300. This
decision is based on the Administrative Record file for this
site.
The State of Nebraska concurs on the selected remedy. A
letter from the State of Nebraska stating its concurrence is
included in this Record of Decision (ROD) package.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangeDment to public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
The selected remedy is intended to be a final remedial
action for the site and addresses all contamination associated
with the principal threats posed by the site. The selected
remedy addresses the volatile organic compound contamination
identified in the soil and the ground water.
The major components of the selected remedy include:
Potable water, meeting Maximum Contaminant
Levels (MCLs) defined by the federal Safe
Drinking Water Act and the Nebraska Title
118, provided to the Park Mobile Home Court
and other properties located within the
contaminated "ground water aquifer, or
unacceptably threatened by it;
The removal of the Underground Storage Tank
(UST), the concrete settling basin, and the
septic tank from the UST area. Soil samples
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will be collected and analyzed to determine
whether a soil source of ground water
contamination exists in the area. Treatment
measures such as excavation and soil vapor
extraction will be implemented to address an
identified soil source which exceeds the soil
restoration levels;
Excavation and low-temperature thermal
treatment of contaminated soils which exceed
the soil restoration levels in the CS/CN
area;
A ground water extraction and treatment
system which will hydraulically control the
entire CS/CN and UST source area ground water
plumes, including the contaminated ground
water north of the Sherwood Medical Company
property. As a minimum, the extraction
system will include ground water extraction
wells located in the UST area, the CS/CN
area, the area in which monitoring well
cluster 7 is located, and the property
located north of the Sherwood Medical Company
property. The extraction system will be
designed to achieve Safe Drinking Water Act
standards (SDWSs) throughout the contaminated
aquifer within five years. Air stripping
technology will be used to treat the
extracted ground water. The treated ground
water may be discharged to either the Elkhorn
River or reinjected into the aquifer;
Ground water cleanup will be accelerated
through treatment if the ground water does
not meet SDWSs within five years from the
startup of the ground water extraction and
treatment system;
A ground water monitoring program to monitor
and evaluate changes in ground water quality;
and,.
A deed restriction to prohibit land
disturbance at the UST and CS/CN areas after
excavation, and the use and installation of
ground water supply wells in the contaminated
portion of .the aquifer on the Sherwood
Medical Company property.
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STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. The remedy satisfies the
statutory preference for remedies that employ treatment and
reduce the toxicity, mobility, or volume as a principal element,
and utilize permanent solutions and alternative treatment
technologies to the maximum extent practicable.
This remedy will not result in hazardous substances
remaining onsite above health-based levels. However, because
hazardous substances in the ground water may take five years or
more to reach SDWSs, a review of the remedial actions will be
made no less often than every five years after initiation of the
remedial action and will continue until SDWSs are achieved in the
ground water.
7 - 2. ~~ 7' 3
Date
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STATE OF NEBRASKA
DEMlnMENT OF aMRONMEHrAL QUAUTY
~ Wood
DiIftfOt
SuiIe 400. The Alnum
1200 ON' SIrftt
P.O. Box 98922
Unc:oIn. NebrasIca 68S09-8922
Phone 44021 471-2186
E. Benjamin Neilan
Go_r
SEP 2 9 1993
William W. Rice
Acting Regional Administrator
u. S. EPA Region VII
726 Minnesota Ave.
Kansas City, KS 66101
Dear Mr. Rice:
The Nebraska Department of Environmental Quality has reviewed the draft Record of
Decision for the Sherwood Medical Company Superfund site at Norfolk, Nebraska.
We understand EP A's selected remedy will include continuing delivery of safe drinking
water to affected residences, remediating the entire contaminated aquifer, and clean-up of
contaminated soil source areas.
We believe the selected remedy will be protective of human health and the
environment and will comply with State law. The selected remedy is also the best balance of
effectiveness, implementability, and cost. Therefore, the Department concurs with the EPA
proposed Record of Decision for the Sherwood Medical site.
k?IQ ~
Randolph Wood
Director
kfQ.vw
OCT 4 1993
REGIONAL. ~DM'N'STRA1OR
AIIEquJ~/~AaIcIn~
~-..,_..-.--
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RECORD OF DECISION
DECISION SUMMARY
SHERWOOD MEDICAL COMPANY SITE
NORFOLlt, NEBRASKA
PREPARED BY:
u.S. Environmental Protection Agency
Region VII
ltansas City, ltansas
SEP'l'ENBER, J.993
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TABLE OF CONTENTS
1.0
SECTION
SITE NAME, LOCATION AND DESCRIPTION
~
1
2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIES
1
3.0
HIGHLIGHTS OF COMMUNITY PARTICIPATION
8
4.0
SCOPE AND ROLE OF RESPONSE ACTION
9
5.0
SUMMARY OF SITE CHARACTERISTICS
9
6.0
SUMMARY OF SITE RISKS
11
7.0
DESCRIPTION OF ALTERNATIVES
14
8.0
SUMMARY OF THE COMPARATIVE ANALYSIS OF
ALTERNATIVES
3S
9.0
THE SELECTED REMEDY
39
10.0'
STATUTORY DETERMINATIONS
41
11.0
DOCUMENTATION OF SIGNIFICANT CHANGES
41
APPENDIX A - GLOSSARY
RESPONSIVENESS SUMMARY
i
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FIGURE 1.
FIGURE 2.
FIGURE 3.
FIGURE 4.
FIGURE 5.
FIGURE 6.
FIGURE 7.
. FIGURE 8.
FIGURE 9.
FIGURE 10.
LIST OF FIGURES
PAGE
SITE LOCATION MAP
2
SITE MAP
3
WASTE MANAGEMENT PRACTICES
5
LOCATION OF POTENTIAL SOURCES
7
LOCATION OF TWO GROUND WATER PLUMES
12
NEW WELL LOCATION FOR ALTERNATE
WATER SUPPLY
19
ALTERNATIVE 4 EXTRACTION WELL LOCATIONS
22
ALTERNATIVE 5 INJECTION AND EXTRACTION
WELL LOCATIONS
24
ALTERNATIVE 7 EXTRACTION WELL LOCATIONS
27
ALTERNATIVE 10 EXTRACTION WELL
LOCATIONS.
29
ii
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TABLE 1.
TABLE 2.
TABLE 3.
TABLE 4.
TABLE S.
LIST OP TABLES
TOTAL NONCARCINOGENIC HAZARD INDICES
FOR RESIDENTIAL EXPOSURES
PAGE
lS
TOTAL NONCARCINOGENIC HAZARD INDICES
FOR COMMERCIAL/INDUSTRIAL EXPOSURES
lS
TOTAL CARCINOGENIC RISK FOR
RESIDENTIAL EXPOSURES
16
TOTAL CARCINOGENIC RISK FOR
COMMERCIAL/INDUSTRIAL EXPOSURES
16
REMEDIAL ALTERNATIVES
17
iii
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SECTION 1. 0
SITE NAME. LOCATION AND DESCR.IPTION
The Sherwood Medical Company (SMC) site is located in
Madison County, Nebraska, approximately 1.5 miles south of
Norfolk (population approximately 21,000), adjacent to U.S.
Highway 81 (Figure 1). Specifically, the site is located in the
SW 1/4, Section 3, T23N, R1W, 6th Principal Meridian. The area
of the site is approximately 66 acres. The northern portion of
the site, comprising 19 acres, consists of the Park Mobile Home
Court (PMHC) where approximately 55 residences are located
(Figure 2). The southern portion of the site comprises 47 acres
and encompasses the SMC property. The SMC property includes the
SMC building and Sherwood Lake.
The SMC site is surrounded by residential and commercial
properties, and notable topographical features, as shown in
Figure 1. The Karl Stefan Airport is located immediately to the
west. Medelmans Lake and the Elkhorn River are located north
within one mile of the site. Commercial and residential
properties are located immediately south, north and east of the
SMC site. The population is approximately 50 for the residences
located south of the site along Sherwood Road. Ground water is
the only source for commercial and residential water needs south
of the Elkhorn River.
The local, flat terrain is a drainage basin for the Elkhorn
River. Recreational areas near the site include Medelmans Lake.
The lake is reportedly stocked with fish and boating, fishing,
and swimming do occur. It should be pointed out that an active
gravel mining operation is located at the south end of Medelmans
Lake and that recreational activities are generally confined to
locations away from the mining operation. .
SECTION 2.0
SITE HISTORY AND ENPORCEMEN'1' ACTIVITIES
2.1
Site Historv
The SMC property was originally used for agricultural .
purposes. The SMC building was built by Brunswick Corporation in
1961 and was operated as Roehr Products until 1967, when its name
was changed to Sherwood Medical Company, Inc. In 1982, American
Home Products Corporation acquired SMC.
Hand operated medical syringes have been produced at the
facility since its construction. A polypropylene injection
molding process is used to produce the syringe components. In
1974, the facility added a production line in which purchased
components are assembled into glass blood collection systems.
Information submitted by SMC indicates that waste disposal
practices have changed as the facility expanded and as production
processes were modified. Originally, as indicated by SMC, the
1.
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facility floor drains were installed to convey drainage effluent
to Sherwood Lake. These floor drains included the lines from the
boiler and tool rooms, the principal locations where chlorinated
solvents (sources of volatile organic compounds or VOCs) were
used. In 1967, the boiler room and tool room lines were
redirected to an existing septic tank system located in the
southwest corner of the SMC property. Effluent from the septic
tank discharged to two leach fields. In 1970 to prevent leach
field oil clogging, the liquids from the tool and boiler rooms
were discharged to an underground storage tank, pending periodic
removal by a waste hauler. In 1974, SMC built a sewage treatment
plant (STP). At that time, all lines, with the exception of the
boiler and tool room lines, were rerouted to the STP. In
September 1989, the boiler and tool room lines were redirected to
the sewage treatment plant. Figure 3 depicts the changes in
waste disposal practices as submitted by SMC.
Land disturbance on the SMC property and referred to as the
CS/CN area (Figure 2) is visible on site aerial photographs taken
during the 1960's and 1970's. SMC has stated that this area may
have been used for refuse disposal, but that SMC has never used
this area for waste disposal. The EPA presently has no
information, other than that provided by SMC, regarding the
source of contamination in that area.
2.2
Site Investiqations
The Nebraska Department of Health (NDOH) periodically
samples all public drinking water supplies in the State of
Nebraska. An NDOH sample collected in October 1987 from the PMHC
water system was found to contain VOCs. NDOH collected samples
from the PMHC main and backup wells in November 1987 and
confirmed that VOCs were present in both wells. The VOCs present
included 1,1-dichloroethene (DCE), 1,1-dichloroethane (DCA),
1,1,1-Trichloroethane (TCA), tetrachloroethene
(PCE),trichloroethene (TCE), and vinyl chloride (VC).
Concentrations for several of the VOCs exceeded state and federal
Drinking Water Max~ Contaminant Levels (MCLs) established
pursuant the federal Safe Drinking Water Act.
In December 1987, the NDOH sampled other supply wells in the
area in an effort to determine the extent of contamination. VOCs
were detected in samples from SMC well SM3 and the Ohlrich supply
well (Figure 2). The NDOH notified the Nebraska Department of
Environmental Quality (NDEQ), which subsequently notified the
U.S. Environmental Protection Agency (EPA). In 1988, the EPA
supplied the PMHC residents with potable water first by providing
bottled water and then by installing an activated carbon water
treatment system on the PMHC main water supply well.
The EPA conducted Phase I of an Expanded Site Investigation
(ESI) of the area in July 1988. The objective of the ESI was to
4
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FIGURE 3.
SHERWOOD MEDICAL
DIAGRAM OF WASTE
PRACTICES
COMPANY'S
MANAGEMENT
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identify the source and approximate areal extent of the
contamination associated with the VOCs. The investigation
included an active soil gas survey across the SMC property, a
magnetic and electromagnetic geophysical survey of two potential
contaminant source areas, the collection of Sherwood Lake surface
water and sediment samples, and collection of SMC effluent
discharge samples. The results of Phase I of the ESI were
presented in a report in December 1988.
Phase II of the ESI was conducted in January 1989 and
consisted of a second soil gas survey, and collection of ground
water samples from 24 residential drinking water wells and one
temporary monitoring well. Phase II results were presented in a
trip report in February 1989, 'and in a memorandum in May 1989.
Copies of the ESI reports are contained in the
Administrative Record. The following findings summarize the
results of the two phases of the ESI. The soil gas survey
indicated the presence of a TCA soil gas plume located on the SMC
property, and a PCE soil gas plume which overlaps the TCA plume
on the SMC property but also extends northeast toward Medelmans
Lake. Ground water collected from supply wells on the SMC and
Ohlrich properties contained VOCs, with the highest levels
identified in the SMC wells exceeding MCLs. The contamination
levels found in the Ohlrich well were below MCLs. The ESI
identified four possible contaminant source areas on the SMC
property: the Underground Storage Tank (UST) area located west
of the SMC building, the Cullet Silo area located between
Sherwood Lake and the SMC building, and the CS/CN and the Grassy
Knoll Areas located north and northeast, respectively, of
Sherwood Lake (Figure 4) .
2.3
Enforcement Histo~
As a result of the information developed by NDOH, and
investigations conducted by the NDEQ and the EPA, including the
ESI, the EPA notified Sherwood Medical Company in December 1988
that it was a Potentially Responsible Party (PRP), as defined and
described in CERCLA.
On September 6, 1989, SMC entered into a Removal Action
Administrative Order (AO) with the EPA. Under the terms of the
Removal Action AO, SMC decommissioned the septic tank system
(also referred to as the Underground Storage Tank area - UST
area). Inspection of the septic system identified good integrity
of the various tanks. However, portions of the PVC piping used
for tank connections were dissolved which may have .allowed for
contaminants to leak .into the soils and aquifer. The septic tank
system was cleaned and decommissioned by December 1990.
The Removal Action also included the provision of potable
water meeting Safe Drinking Water Standards (SDWSs) to PMHC. SMC
6
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LOCATION OF POTENTIAl
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-------
installed a new water treatment system on the SMC property and
constructed a pipeline connecting the SMC treatment system to the
PMHC distribution manifold. In September 1989, SMC began
supplying potable water meeting SDWSs to the PMHC. In addition,
SMC was required to monitor the quality and volume of the
supplied water and to submit the results to NDOH, NDEQ and EPA,
on a monthly basis.
On April 2, 1991, NDEQ and SMC entered into a Consent Decree
concerning past waste handling practices and future cleanup in
the septic system by SMC pursuant to the Nebraska Environmental
Protection Act (NEPA) Neb. Rev. Stat. ~81-1501 ~ seq. The
settlement specified that SMC would pay a fine, and Nebraska
Title 118 - Ground water Quality Standards and certain
substantive requirements of Nebraska Title 128, the hazardous
waste laws, would be applicable or relevant and appropriate
during the cleanup.
On March 21, 1991, SMC entered into a second AO with EPA to
conduct a Remedial Investigation (RI) and Feasibility Study (FS),
pursuant to the requirements of Sections 104 and 122 (d) (3) of
CERCLA, 42 U.S.C. ~ 9604 and 9622(d) (3). SMC was required to
conduct an RI which would define the extent of contamination in
ground water, surface water, surface soils and subsurface soils.
Also, treatability studies would be conducted as needed to
develop the FS. Results of the RI and FS activities are
summarized in Sections 5.0 and 7.0, respectively, of this Record
of Decision. Copies of the actual RI and FS reports are included
in the Administrative Record.
The Sherwood Medical Company Site was proposed for the
National priorities List (NPL) on July 29, 1991 (56 Federal
Register 35840). The site was placed on the NPL October 14, 1992
(57 Federal Register 47180) .
SECTION 3.0
HIGHLIGHTS OP COMMDNITY PARTICIPATION
The RI/FS and Proposed Plan for the site were released to
the public on August 20, 1993. The Administrative Record file,
which included the RI/FS reports and the Proposed Plan, was made
available to the public at the information repositories
maintained at the City Auditorium, in Norfolk, Nebraska, and at
the EPA Region VII Superfund Records Center, Kansas City, Kansas.
The notice of availability for these documents was published in
the Norfolk News on August 17, 1993.
A public comment period was held from August 20, 1993
through September 20, 1993. During the public comment per~o~, a
public meet~ng was held on August 31, 1993. Interested c~t~zens
were notified about the public meeting through the August 17
notice in the Norfolk News and through letters sent to
8
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individuals by EPA's Public Affairs (PBAF) Offices.
the PMHC received letters from EPA's PBAF office.
Residents of
At the public meeting, representatives from the EPA and NDEQ
answered questions about the site and the remedial alternatives
under consideration. A transcript of the public meeting is
included in the Administrative Record. A response to the
comments received during this period is included in the
Responsiveness Summary, which is part of the Record of Decision.
In summary, the public participation requirements as defined in
CERCLA Sections 113(k) (2) (B) (i-v) and 117 were satisfied.
This decision document presents the selected remedial action
for the Sherwood Medical Company Site, in Norfolk, Nebraska,
chosen in accordance with the provisions of CERCLA, as amended by
SARA, and the National Contingency Plan (NCP). The selection of
a response action for this site is based on the Administrative
Record.
SECTION 4.0
SCOPE AND ROLE OP RESPONSE ACTION
This Record of Decision addresses all contaminants
identified at the site in each media, including ground water and
soils.
Three principal threats, current and potential, were
identified: the contaminated ground water originating on the SMC
property and extending toward Medelmans Lake, the contaminated
subsurface clay unit located in the CS/CN area and the subsurface
residual contamination in the UST area. The remedial action
objective for this site is to eliminate the current and to
prevent future unacceptable exposures due to these three
principal threats. These actions are expected to be the final
response actions for the SMC Site.
SECTION 5.0
SUMMARY OP SITE CHARACTERISTICS
From March 1991 to July 1993, SMC conducted Remedial
Investigation and Feasibility Study activities pursuant to an AO
issued by EPA. The objectives of the RI/FS were:
(1) to identify and define the extent of contamination in the
soil, sed~ent, surface water and ground water, (2) to provide
the information which enabled EPA to calculate the risks
associated with the contamination, and (3) to develop
alternatives for cleanup of the contaminants. The activities and
investigations conducted during the RI provided the following
information:
9
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HYDROGEOLOGY
The subsurface of the SMC site consists of 59 to 69 feet of
alluvial deposits overlying the Niobrara Chalk Formation. The
alluvium is predominantly poorly-graded, very fine to fine
grained sand with a trace to some silt, and a trace to some
gravel. A six-foot thick clay layer exists in the CS/CN area
starting at a depth of eight to ten feet below ground surface.
The surface dimensions of this clay layer are at least 170 feet
by 100 feet.
The water table was encountered at depths ranging between
five and 15 feet below ground surface. The water table elevation
is sensitive to local weather conditions. Ground water in the
alluvial aquifer flows in a northeastern direction toward
Medelmans Lake where it discharges. The horizontal and vertical
ground water flow velocities in the alluvium at the site can be
expected to be about 800 ft/yr and 1 ft/yr, respectively.
Ground water flow in the bedrock is also to the northeast.
The results of a bedrock pump test indicate that the upper
fractured portion of the Niobrara Formation is apparently
hydraulically connected to the overlying alluvial aquifer and
responds to pumping in that it draws water from the overlying
alluvium. Ground water flows vertically downward from the
alluvium to the bedrock for the southwest and central portions of
the site. In the northeast portion of the site, an upward
vertical ground water flow exists due to the natural discharge to
Medelmans Lake and eventually to the Elkhorn River.
SOURCES
Soil contamination above the water table is presently
limited to the CS/CN area. The clay layer acts locally as a
barrier to vertical migration of contaminants. PCE and TCA were
detected in concentrations ranging up to 3400 mg/kg and 580
mg/kg, respectively. The areal extent of soil contamination in
the CS/CN area is limited to an area approximately 90 feet in
diameter, which is estimated to be 1100 cubic yards of VOC
contaminated soils.
Low levels of toluene and gasoline contaminants were
detected in the subsurface soil in the Grassy Knoll and CUllet
Silo areas, respectively. Ground water contamination has not
been identified to exceed health based standards in these two
areas.
Subsurface soil" contamination below the water table may
exist in both the UST and CS/CN areas. PCE was detected at a
concentrati~n as high as 2,400 ug/kg at a depth of 8-10 feet in
the UST area. PCE was also detected as high as 66 ug/kg at a
depth 12-14 feet in the CS/CN area.
10
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The sediment and surface water in Sherwood lake are not
contaminated. The septic system equipment is not contaminated.
GROUND WATER
Two ground water plumes exist at the SMC site (Figure 5).
The larger of the plumes originates at the UST area. The most
prevalent UST plume contaminant is PCE, followed by TCA and DCE.
The maximum UST plume concentrations of PCE, TCA and DCE are
3,700, 1,600 and 650 ug/l, respectively. The downgradient edge
of the plume resides near monitoring well nest 14 (Figure 2) just
southwest of Medelmans Lake. The eastern edge in the UST plume
extends beyond Sherwood Lake and the western edge is east of well
nest 12. The bulk of the plume is located by depth in the middle
section (20 to 40 feet below the surface) of the alluvial
aquifer.
The source of the second ground water plume is located at
the CS/CN area. The major plume contaminants are TCA, PCE, DCE,
and DCA, which were detected at maximum concentrations of 39,000,
8,800, 3,500 and 1,700 ug/l, respectively. The downgradient edge
of the CS/CN plume is located south of Medelmans Lake. At well
nests 8 and 10, the majority of contamination is located in the
upper portion of the alluvial aquifer. At well nest 11, most of
the contaminants are located in the middle portion of the
alluvial aquifer.
SECTION 6.0
SUMKARY OP SI'1'E RISU
As part of the RI/FS process, the EPA developed a Baseline
Risk Assessment (BRA) to estimate the human health and
environmental risks associated with possible exposure to
contaminants identified at the site. A copy of the BRA is
included in the Administrative Record. The BRA was conducted in
accordance with all relevant and current EPA risk assessment
guidance. First, contaminants of potential concern were
identified. Then, the potential toxicity of these contaminants
was reviewed, potential exposures were described and quantified,
and risk characterization was performed. This analysis provided
valuable information used to determine the need for remedial
action (s) .
'1
The contaminants of potential concern (COPCs) in ground
water are volatile organic compounds: benzene, 1,1-
dichloroethane, 1,1-dichloroethene, tetrachloroethene, 1,1,1-
trichloroethane, 1,1,2-trichloroethane, trichloroethene and vinyl
chloride. In subsur~ace soil, the COPCs are tetrachloroethene,
1,1,1-trichloroethane, 1,1,2-trichloroethane and methylene
chloride. ~early all the COPCs identified in ground water are
viewed by the EPA to be .possible" or "probable" human
carcinogens and several of them are also known to have adverse
11
-------
t
L_~
Med8Im- u..
......... tIIrveI.. No8tb.... ..... & 0.'"
"8IMti" 0 c=J
,
.
,
,,,..._......,.
c;l.r"~ I:a Cf(:}--d"'
tl MeIr We'
Sh8rwGOd Ro8d
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o
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ft Oroundw..., FbrOlrer:tlon
.
II
ApprOllIntI'e SI. Boundlry
Oth.. SlMJ'V w..
Indualrfll w.n Ind NudJer
e
MonItoring Wellnd Number .
-
Po'enlla' Ar.a. of Concern
SUfface WI'" and Seclmerf
SlenpI8lGC:I'1on
.
I
2G8 -m
IICAIf "nET ~
LOCA!'IOH 01' 90 GROUND
WA!'8R PLUM8S
_J
-------
noncarcinogenic health effects. Consequently, both
noncarcinogenic health hazards and carcinogenic risks due to
exposure to these compounds were evaluated.
The potential for noncarcinogenic health risk is evaluated
by comparing estimated contaminant intake to a reference dose.
The ratio of contaminant intake to the reference dose is referred
to as the hazard quotient or hazard index. A hazard quotient
greater than one indicates that a hazard may be likely to exist.
Since the estimated contaminant intakes calculated in the BRA
represent conservatively high estimates, the calculated hazard
quotients represent conservatively high risks.
The potential for carcinogenic risk is estimated by
multiplying estimated contaminant intake by an established slope
factor for each contaminant. The resulting figure represents the
chance that a receptor would develop cancer in excess of a
background incidence. For example, a risk of one in ten thousand
(represented as 1 X 10" or as 1E-4) indicates that one
additional person may contract cancer out of 10,000 people
identically exposed to a contaminant. A cancer risk greater than
one in ten thousand ( represented as 1 X 10" or 1E-4) is
considered unacceptable and requires remedial action. A cancer
risk less than one in one million (represented as 1 X 10-6 or 1E-
6) is considered acceptable. The cancer risk range between
1 X 10-6 and 1 X 10.' is considered acceptable unless site
specific conditions warrant otherwise. The calculated
carcinogenic risks ordinarily would be viewed as conservatively
high due to the EPA's carcinogenic risk assessment methodology.
However, for this site, the carcinogenic risks may be
underestimated due to the presence of carcinogens
1,1-dichloroethene and tetrachloroethene at concentrations
exceeding the range of applicability of their slope factors. As
a result, the carcinogenic risks for those two contaminants could
not be calculated.
The BRA evaluated potential exposures via all media:
surface soil, subsurface soil, sediment, surface water, ground
water and air. This analysis identified ground water as the only
medium of potential human health concern. The exposure pathways
evaluated include residential and commercial/industrial
scenarios. The residential scenario involves the exposure of
adults and children to ground water COPCs via ingestion, dermal
contact and inhalation. The commercial/industrial scenario
involves the exposure of workers to ground water COPCs via
ingestion.
The RI data have consistently indicated the presence of two
ground water contamination source areas. Therefore, separate
ground wat~r exposure point concentrations were calculated for
the UST area and the CS/CN area. In addition, health risks were
calculated for exposure to concentrations identified at the
13
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Ohlrich well, and the Medelmans well, and the most highly
contaminated monitoring well (well nest 8). The Ohlrich and
Medelmans exposures are evaluated because the ground water
contamination would move to those properties if not addressed
through cleanup actions.
Tables 1 and 2 summarize the noncarcinogenic health hazards.
The noncarcinogenic hazard quotients exceed one for all exposure
scenarios evaluated, except the Ohlrich and Medelmans scenarios,
for which the calculated hazard indices are zero. Thus, a
noncarcinogenic health hazard potentially exists at this site.
Tables 3 and 4 summarize the carcinogenic risks. The
potential, total carcinogenic risks associated with both
residential and commercial/industrial settings for the CS/CN
area, UST area and well 8 location either exceed the 1 X 10-'
criteria, or would have exceeded the 1 X 10-' criteria if the
risks due to tetrachloroethene and 1,1-dichloroethene could have
been calculated as previously discussed. The total carcinogenic
risks calculated for commercial/industrial exposures at the
Ohlrich and Medelmans' wells do not exceed the 1 X 10-6 to
1 X 10-' criteria.
The calculated potential risks are based on ingestion,
inhalation and dermal contact to contaminants through exposure to
contaminated ground water. However, exposures to contaminated
ground water at the site are not currently occurring.
An environmental risk characterization was performed as part
of the BRA. Under current conditions, no adverse impacts were
identified for the local flora and fauna ecosystems.
Actual or threatened release of hazardous substances from
this site, if not addressed by the response action selected in
this ROD, may present a current or potential threat to public
health, welfare, or the environment.
SECTION 7.0
DESCRIPTION OF ALTERNATrvES
Description of Alternatives
Thirteen alternatives analyzed in detail are presented below
and summarized in Table s. These alternatives were presented in
the Proposed Plan. All costs and implementation times are
estimated.
Common Elements for Alternatives 2 through 13
A deed restriction would be placed on the SMC property by
SMC to prohibit land disturbance at the UST and CS/CN areas
(effective after completion of cleanup activities) and the use
14
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TABLE 1.
TOTAL NONCARCINOGENIC HAZARD INDICES
FOR RESIDENTIAL EXPOSURES
EXPOSURE ROtrTES
CONTAMINANT CS/CN AREA MW-08 UST AREA
1,1,1-TRICBLOROETHANE 1.9 9.2 0.0
(1,1, 1-TCA)
1,1,2-TRICBLOROETHANE 0.2 0.4 ND
(1,1,2 -TCA)
1,1-DICBLOROETBANE 0.1 0.4 0.0
(1, 1-DCA)
1,1-DICBLOROET~ 5.9 31.6 0.0
(l,l-DCE)
TETRACBLOROE'l'BENE 3.9 14.2 9.2
(PCE) --------- ------- ------
TOTAL INDICE FOR: 12.0 55.8 9.2
EXPOSURE ROUTE
TABLE 2.
TOTAL NONCARCINOGENIC RAZARD INDICES FOR
COMMERCIAL EXPOSURES
EXPOSURE ROUTE
CS/CN UST OHLRICH MEDELMAN
CONTAMINANT AREA MW-08 AREA WELL WELL
1,1,1-TCA 0.6 2.6 0.0 0.0 0.0
1,1,2-TCA 0.1 0.1 ND ND ND
1,1-DCA 0.0 0.1 0.0 0.0 0.0
1,1-DCE 2.1 10.9 0.0 0.0 0.0
PCE 1.3 4.9 3.2 0.0 0.0
----- ------ ----- ----- -----
TOTAL INDICE: 4.1 18.6 3.2 0.0 0.0
FOR. EXPOSURE
ROtrTE
ND a NOT DETECTED
15
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TABLE 3.
TOTAL CARCINOGENIC RISE POR RESIDENT~ EXPOSURES
CONTAMINANT
BENZENE
1,1-DICBLOROET~
(l,l-DCE)
TETRACBLOROE'.L'~
(PeE)
1,1,2-TRICHLOROETHANE
(1,1,2-TCA)
TRICHLOROETHYLENE
(TCE)
VINYL CHLORIDE
(VC)
TOTAL RISE POR:
EXPOSURE ROtJTE
EXPOSURE ROtrrE
(NOTE: 1. OE - 6 = 1 X 10-6)
CS/CN AREA MW-OB
1.4E-06 1.6E-06
U'ST AREA
ND
3.1E-03 NC 2.0E-OS
7.9E-06 NC NC
4.6E-OS 1.lE-04 ND
S.lE-OS 2.4E-04 1.0E-06
S.BE-OS B.7E-OS ND
--------- --------- ---------
3.2E-03 4.4E-04 2.1E-OS
TABLE 4. TOTAL CARCINOGENIC RISE POR COMMERCIAL EXPOSURES
EXPOSURE ROUTE
(NOTE : 1. OE - 6 . 1 X 10 -6)
csteN' t7ST OHLRICH MEDELHAN
CONTAMINANT AREA MW-OB AREA WELL WELL
BENZENE 2.1E-07 2.4E-07 ND ND ND
1,1-DCE S.lE-04 NC 2.2E-06 1.7E-06 1.7E-06
PCE 2.3E-06 NC NC 2.0E-07 1.9E-07
1,1,2-TCA 4.BE-06 1.lE-OS ND ND ND
TCE 6.4E-06 3.0E-OS 1.3E-07 3.1E-OB 2.3E-OB
VC 1.SE-OS 2.3E-OS ND ND ND
------- ------- ------- ------- -------
TOTAL RISE: S.4E-04 6.4E-OS 2.3E-06 2.0E-06 1.9E-06
POR EXPOSURE ROUTE
ND = NOT DETECTED
NC = CARCINOGENIC RISE NOT CALCOLATED J WATER CONCENTRATION
EXCEEDS LOW DOSE EXTRAPOLATION RANGE.
16
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TABLB 5.
REMBDIAL ALTERNATIVES
.. A CHECK MARK INDICATES THAT THE TECHNOLOGY IS INCLUDED ..
..
....
.--.
:e8H8t Td"'" ;"';;'\L; ~T. .;;,r . .
fo ., ALT' ALTI ALTJ .ALTS Al.T' ALT'l ALr. ALT' ALT'. fff.' ~T~ AL'1' 13
.n.... At'''' -: ~. . . . ..
-
No Action No' Action "
--
Instkullonal Access Restnctlons (Deed " " " " " " " " " " " I
Actions Restnalons on Ground Waler Use
and Soli Aalwitics)
- -
Altemale W.le, Surrly " " " " " " " " " " " ,
- -
MoniiOrinS (Ground Waler) " " " " " " " " " " " I
-
Conectinn' (irnund Waler Collect inn (Source " " " " " " " " " I
Removal Actions Arnsr
-
{hound Waler Collection (enllre ,/ ,/ I
"ume)
--
I!uavalinn 0' Soils " " " " " I
---
(n.JUnd Wiler Chemical/Physical T'ealmenl (AI, " ,/ " ,/ " ,/ ,/ .
.
Trealmenl Srr~lplnl)
AL110ns
Pinlogical Trealmenl "
,,, Si,u Oiological Trealmenl "
--
Air Sparlins " "
Soil Trellmenl Thermal Trealmenl (tow ,/ " " " ~
Actiuns 1'emperlllurc Thermll Trcalmenl)
--
DinluSicd Trealmenl "
- - _==1
'" Siru Diolulical Trealmenl "
-
51111 Vapllr I!suaaion " " " " :!J
- - -
Trealed Cirllund UiKharle III P.1'hurn River " " " " ". "
Wiler - -
Disrosiliun Heinjeaiun inlO Aquircr " "
.. .. '-
-------
and installation of ground water supply wells in the contaminated
portion of the aquifer on the SMC property. These deed
restrictions may be removed upon achieving soil and ground water
performance standards and ARARs which are presented later in
Section 7.0.
Potable water which meets Safe Drinking Water Standards
(SDWSs) would be provided to the PMHC and the other properties
located within the contaminated ground water plume. The PMHC
water would be supplied by well SM3 or by a new supply well
located in an unaffected portion of the aquifer. For cost
estimating and feasibility purposes, an acceptable location for
the new well was identified east of SM3 as shown in Figure 6.
Bottled water meeting SDWSs would be supplied to meet the needs
for the commercial properties if the levels of VOC's exceed MCLs.
The provision of potable water will cease when SDWSs are achieved
in the impacted private wells, and when pumping the private wells
will not extract contaminated ground water.
A ground water monitoring program would be implemented using
existing and, as necessary, new monitoring wells. Data from the
ground water monitoring program would be used to evaluate the
effectiveness of cleanup actions and to monitor changes in ground
water quality. For cost estimating purposes, the program was
assumed to include the following existing upgradient wells (lA,
lB, lC), downgradient wells (llA, 11B, 11C, 14A, 14B, 14C) ,
peripherial wells (9B, 9C, 12B), and within the plume wells (4A,
6B, 6C, 7B, 7C, 8A, 8B, lOA, 13A). Refer to Figure 6 for
locations of the wells. Quarterly sampling and VOC analyses were
assumed for cost estimating purposes.
The UST, the concrete settling basin, and the septic tank
would be removed from the UST area. During the removal, soil
samples would be collected and analyzed to determine whether a
source of ground water contamination exists in the area. Soil
performance standards as defined at the end of Section 7.0 would
be used to define whether a soil source exists in the UST area.
VOC concentrations in the UST area exceeding the UST soil
performance standards would be classified as a soil source for
ground water contamination and would be remediated using the same
soil treatment measures evaluated in the FS such as soil vapor
extraction or excavation and low temperature thermal treatment.
Alternative 1
Present Worth Cost: $ 0
Years to Complete Cleanup:
At least 30 years
This is the no .action alternative required for evaluation by
the National Contingency Plan. No actions would be taken to
reduce the-potential for exposure of humans to site contaminants.
The restoration of soil and ground water would be eventually
accomplished through natural attenuation processes. Through
18
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FIGURE 6.
POSSIBLE LOCATIONS FOR
MONITORING WELLS AND FOR
ALTERNATE WATER SUPPLY WEI
-- "---- .- . '._0.-
----.-
.~ - - -.-. -.--.
----'.
r-='--J
L- rr'-
t...
---, -- -----
.\.,
D
o
lit...... .,.
0: 0
LW.IID
- ...... ...
-..ill ... .. -
eaSM)
I
.
8'MI
. ONICfiI ...
-... ... ""'
- -.....
...
- - t'.-,
01'''' ...
PI8C - ...
f
...
U)
(j)
.
;;
lite s.wr ...
r--
I
I
I
I
I
I .
I
I
I
I
CS/CN .
AREA..
~~--
,. ~'f
I
I
:0
~g
~ W~-- _mNOAO
f.~- ...
....... .. 51<.,. 1.-
..
4
.
t
.
It
oil
:>
."
~
o
i)()
':1,.J
:,:::') ()
I, ,
~:;.f~' t;.
( ,- " ~
I?- ,./
tJ' r"_d
a-- ~",.
:l
Sfttrwtof
,...
T) tUllE I .D
SI SILO} J
R AREA AREA \l
l ~.~
~~-~CJ .
n CJ 8f) 0 CI CO
Q '00 zoo )00
SC"if .. 'ff I
"SM)
CJ
Q
.- "-'-..
.- .-.----. ---..- .
... .""---.--.-.-.,- ----
..._,- _. -- -- .- .-
-.. ..- '- -.---.-..- .---
-------
natural attenuation, ground water contaminants would be
transported through the aquifer toward Medelmans Lake, resulting
in a larger volume of contaminated ground water and higher
contaminant levels in ground water north of the SMC property.
The timeframe required to restore ground water to SDWSs can not
be calculated because the CS/CN and UST sources are not
addressed. As a result, these sources would continue to leach
contaminants into the ground water.
Alternative 2
Present Worth Cost: $ 1,197,961
Years to Complete Cleanup: At least 30 years
This is a limited action alternative which reduces the
potential exposure to contaminants through implementing the
common elements of access restrictions, alternate water supply,
ground water monitoring, and UST tank removal. The restoration
of impacted soil and ground water would eventually be
accomplished through natural attenuation processes. The
timeframe required to restore ground water to SDWSs can not be
calculated because the CS/CN and UST sources are not addressed.
As a result, these sources would continue to leach contaminants
into the ground water. The EPA policy is to base the cost
estimate on a 30 year timeframe.
Alternative 3
Present Worth Cost: $ 1,950,014
Years to Complete Cleanup: Less than 1 year for CS/CN Soils,
13 years for CS/CN Ground Water
Plume, and at least 30 years for UST
Source and Ground Water Plume.
This is an active soil restoration alternative which
consists of the common elements and on-site, low temperature
thermal treatment of contaminated CS/CN area soils. Restoration
of contaminated ground water would eventually be accomplished
through natural attenuation processes.
Computer modelling conducted by SMC during the RI/FS process
indicates that within 13 years the CS/CN ground water plume would
naturally attenuate to achieve SDWSs. The timeframe required to
restore ground water in the contaminated plume emanating from the
UST source to SDWSs can not be calculated because the UST source
is not addressed. As a result, the UST source would continue to
leach contaminants into the ground water. The EPA policy is to
base the cost estimate on a 30 year timeframe, which is the
timeframe on which this cost estimate is based.
Soil would be excavated at the CS/CN area; samples would be
collected and analyzed for the presence of VOCs, in order to
determine the extent of excavation. Soil performance standards
as defined later in Section 7.0 would be used to determine the
20
-------
extent of excavation. Contaminated soil would be stockpiled on
an impermeable liner and uncontaminated soil would be returned to
the excavation. Contaminated soils would be treated with a low
temperature thermal treatment unit which volatilizes the VOCs in
a thermal processor. Combustion of contaminants does not occur.
Subsequently, the VOCs are collected by condensing the VOC
contaminated air and trapping the VOCs using a carbon adsorption
system. The carbon is considered a treatment residual and would
be managed appropriately at an off-site facility. Upon achieving
the soil performance standards, the treated soil would be
returned to the excavation and the area would be restored. For
cost estimating purposes, soil data from the remedial
investigation was used to estimate that 1700 cubic yards of soil
would be excavated and treated.
Alternative 4
Present Worth Cost: $ 4,284,339
Years to Complete Cleanup: Less than 1 year for CS/CN Soils,
13 years for CS/CN Ground Water
Plume, and at least 30 years for UST
Source and Ground Water Plume.
This is an active restoration alternative which includes the
common elements, on-site biological treatment of contaminated
CS/CN soils, and on-site biological treatment of contaminated
ground water. All treatment activities would be conducted on the
SMC property.
Soils at the CS/CN area would be excavated; samples would be
collected and analyzed for the presence of VOCs in order to
determine the necessary amount of soil subject to treatment.
Soil performance standards as defined later in Section 7.0 would
be used to determine the extent of excavation. Contaminated
soils would be derocked, pulverized, and slurried with water
containing indigenous bacteria. The slurry would be pumped to a
biotreatment digester in which biodegradation would occur. The
treated, dewatered soil which would meet the performance
standards would be returned to the excavation and the water would
be returned to the slurrying system for reuse.
Contaminated ground water would be collected using
extraction wells. In the feasibility study, computer modelling
techniques were used by SMC to evaluate several ground water
extraction scenarios, and to predict the number, yield, and
location of ground water wells required to meet the goals of the
various alternatives. For Alternative 4, ground water would be
collected in the CS/CN area using a 125 gallons per minute (gpm)
recovery well, and ground water would be collected in the UST
area using a second recovery well pumping 75 gpm. The locations
of the wells are shown on Figure 7. This extraction system would
only recover the contaminated ground water located on the SMC
property. Natural attenuation processes would eventually restore
21
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I'IOURS 7.
ALTIRNATIVI 4 IXTRACTI(
WILL LOCATIONS
._--,--.. ------.-.
..--- ... .-.
- ~-_.- --
. ....-- .--. ...
-----
r_~
'---~-
D D CJ ._"
- - 8..
-,.......... C I '0 .
..-~~c==-----s-_. -=~C:'.~---~-
al''''''' I .NC_- I
i rl' --. ..- - ~~~ Lf':~V'l~ .
t m
I It I.
'"
::J I ."
I I
I I
Soot....
I . l... I
I SM' . I 0
I CUlUI I 0 J.
: I[ :I~ Ii '-.~. J '~;L' ,~ -----
-- I c::::=1T }o ----~ --. -----
21nr n CJ II] D CI DO a Q
~
1It_...
n.' 0
LlliIIII
-""",...
~... ... .. .......
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.
."".
-... ... 1In'
- .........
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0tIII..." ...
.
- - t:...,
~,
...",""."
.
-------
the uncollected, contaminated ground water within an estimated 13
year timeframe.
Extracted ground water would be delivered via pipeline to a
sequencing batch reactor (SBR) system located northeast of the
SMC plant. The SBR would biodegrade the contaminants. Influent
and effluent samples would be collected to verify effective
treatment. The SBR would produce a sludge which would be
classified as a hazardous waste pursuant to the Resource,
Conservation and Recovery Act (RCRA). The sludge would require
proper off-site disposal in accordance with the requirements of
RCRA. Treated ground water would be delivered via pipeline to
the Elkhorn River subject to a State National Pollutant Discharge
Elimination System (NPDES) permit.
~ternative 5
Present Worth Cost: $ 10,102,338
Years to Complete Cleanup: 7 years for CS/CN Soils, 13 years for
CS/CN Plume, and at least 30 years
for UST Source and Ground Water
Plume.
This is an active restoration alternative which consists of
the common elements, and in-situ biological treatment of
contaminated CS/CN and UST soils, and of contaminated ground
water. All treatment activities would be conducted on the SMC
property.
Contaminated soils in the CS/CN area would be biodegraded
through percolation of additives into the soil to enhance the
activity of naturally occurring microorganisms.
The in-situ biological treatment of contaminated ground
water would involve the use of an injection and extraction well
system to circulate additives through the aquifer to enhance the
biodegradation processes. Two ground water extraction wells,
each-operating at 50 gpm, would be installed downgradient of the
UST area. After the addition of additives, the ground water
would be reinjected upgradient of the UST area. One extraction
well, operating at 100 gpm, would be installed downgradient of
the CS/CN area. A£ter the addition of additives, the ground
water would be reinjected upgradient of the CS/CN area. The
location of the extraction and reinjection wells are shown in
Figure 8. The reinjection wells would be subject to the
Underground Injection Control (UIC) regulations issued pursuant
to the Safe Drinking Water Act.
This extraction .system would not recover the contaminated
ground water located north of the SMC property. Natural
attenuation-processes would eventually restore the uncollected,
contaminated ground water within an estimated 13 year timeframe.
23
-------
I'IOURB 8.
\ \ I r' C ,'~~~' )
\ i .. I I .. -. i
. '-...1 .1 . .-'----'-=:':J
I ~~=.~~;:;;~ !IT\F)\l' _.~=. \~ .~ .. .11\ , : ."r1. '"'11-
I ::7.~.~ ;,. I '1:1"" . . . "' ~
I. . ... . .. Ot
,..~:: 1,\ \ :..:. - :"-'::-:~:'.~'~~. ~ -' .... ....~-: ' ..h .,.
I' \='"'' . ~~-_.--=---- -- -..----
t') '.'" ... . -.- """ - - I
. ). I .
OJ 1- - -. - --- c~/u~ / r ...
~ ARlAI. .-' CRA$Y
~ I I -~:.,l7
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,
\" i : I.~;~~i" '~~~"~ 1:11,,) :\IJI
\ I : czL. :'l['~- ~ ---~- ""==.' ~'" .",,="--'-.-
il..I.. "-- .:.:=-~-
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t.J
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00
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ALTBRHATIVB 5 INJECTION
AND BXTRACTION WELL LOCA'rI(
II~I
I
.
.
.YI
WiWD
- Suwr ...
""""13' ... ... .......
-,..... .,, .....
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.
CD
CD
Nt. Suppt, .t'
(aI.oc'"" ..,
...,.d... ...
CL ....!0(1 IOU JUtl
SCAl.[ It fU'
-------
Alternative 6
Present Worth Cost: $ 4,573,290
Years to Complete Cleanup: Less than ~ year for CS/CN Soils, ~3
years for CS/CN Ground Water Plume,
and at least 30 years for UST Source
and Ground Water Plume.
This is an active restoration alternative which includes the
common elements, on-site soil vapor extraction of contaminated
CS/CN soils, and on-site treatment by air stripping of ground
water. All treatment activities would be conducted on the SMC
property.
Contaminated soils in the CS/CN area would be treated using
a soil vapor extraction (SVE) system. Extraction and inlet wells
would be installed in the soil above the water table (vadose
zone). A vacuum would be applied to the extraction wells,
thereby creating an air flow through the vadose zone. As air
moves through the soils, VOCs would be transferred from the soil
phase to the gas phase. Air withdrawn from the vadose zone would
be treated using an absorbent system if the VOC emissions exceed
the air performance standards presented later in Section 7.0.
Recovered VOCs would be managed appropriately at a RCRA permitted
off-site facility.
Ground water would be collected using the extraction system
described in Alternative 4 (Figure 6). Extracted ground water
would be treated in an air stripper system located northeast of
the SMC plant. The treated ground water would be discharged in
the Elkhorn River subject to a NPDES permit. Air stripper
technology mixes water and air by passing the two media through
each other in opposite directions. VOCs would be removed from
the ground water and transferred to the vapor phase. The
influent and effluent would be sampled and analyzed to verify
effective removal of VOCs.
Estimated ground water extraction flow rates and removal
efficiencies project that air emissions of contaminants could
exceed the air performance standards presente~ later in Section
7.0. If that would be the case, an absorbent system would be
used to recover the VOCs from the air stripper emissions. The
process residuals would be managed appropriately at a RCRA
permitted off-site facility.
This extraction system would not recover the contaminated
ground water located north of the SMC property. Natural
attenuation processes would eventually restore the uncollected,
contaminated ground water within an estimated 13 year timeframe.
25
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Alternative 7
Present Worth Cost: $ 4,523,860
Years to Complete Cleanup: Less than ~ year for CS/CN Soils, ~3
years for CS/CN Ground Water Plume,
and at least 30 years for UST Source
and Ground Water Plume.
This is an active restoration alternative identical to
Alternative 6, with the exception of ground water discharge.
Alternative 7 would reinject the treated ground water into the
aquifer on the SMC property east of Sherwood lake subject to UIC
regulations. Figure 9 depicts the locations of the extraction
and reinjection wells. The reinjection well would be designed to
operate at 200 gpm.
Alternative 8
Present Worth Cost: $ 4,908,5~3
Years to Complete Cleanup: Less than ~ year for CS/CN Soils, ~3
years for CS/CN Ground Water Plume,
and at least 30 years for UST Source
and Ground Water Plume.
This is an active restoration alternative which includes the
common elements, on-site low temperature thermal treatment of
CS/CN soils, and treatment of ground water using air stripping
technology. Each of these components have been described in
previous alternatives. The ground water extraction system is the
same one described in Alternatives 4 and 6. This extraction
system would only recover the contaminated ground water located
on the SMC property. Natural attenuation processes would
eventually restore the uncollected, contaminated ground water
within an estimated ~3 year timeframe.
Alternative 9
Present Worth Cost: $ 4,859,082
Years to Complete Cleanup: Less than 1 year for CS/CN Soils, 13
years for eS/CN Ground Water Plume,
and at least 30 years for UST Source
and Ground Water Plume.
This is an active restoration alternative identical to
Alternative 8, with the exception that the treated ground water
would be reinjected into the aquifer on the SMC property, subject
to UIC regulations. This extraction system would only recover
the contaminated ground water located on the SMC property.
Natural attenuation processes would eventually restore the
uncollected, contaminated ground water within an estimated 13
year timeframe.
26
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ALTBRNATIVE 7 BXTRACTI'
WELL LOCATIONS
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-------
~ternative 10
Present Worth Cost: $ 5,771,115
Years to Complete Cleanup: Less than 1 year for CS/CN Soils, 5
years for CS/CN Ground Water Plume,
and at least 30 years for UST Source
and GroundWater Plume.
This is an active restoration alternative which includes the
common elements, on-site soil vapor extraction (SVE) of the
contaminated CS/CN area soils, and on-site treatment of
contaminated ground water using air stripping technology.
The only difference between Alternative 10 and Alternative 6
is the ground water extraction system. Alternative 10 would
employ a ground water extraction well system which would
hydraulically control the entire CS/CN and UST source area ground
water plumes, including the contaminated ground water north of
the SMC property. Computer modelling indicates that five
extraction wells located as shown on Figure 10 would restore the
contaminated aquifer, except in the UST area, to SDWSs within
five years. Predicting the time to remediate the UST area ground
water is not possible at this time due to the difficulty in
characterizing the nature of the source in the UST area.
Computer modelling indicates that the following ground water
pumping rates would achieve hydraulic control of the entire
plume: 100 gpm for the UST well, 150 gpm at the well located
near monitoring well 7, 150 gpm at the CS/CN well, and 100 gpm
each for the two wells located north of the SMC property. The
trea~ed ground water would be discharged in the Elkhorn River
subject to an NPDES permit.
For cost estimating purposes, it was assumed that extracted
ground water would initially be treated using two air strippers
located northeast of the SMC building. It is anticipated that
the downgradient portions of the ground water plumes would be
remediated more quickly than the portions surrounding the UST and
CS/CN areas. As the downgradient wells meet SDWSs, all extracted
ground water may eventually be treated by one air stripper.
Alternative 11
Present Worth Cost: $ 6,106,337
Years to Complete Cleanup: Less than 1 year for eS/CN Soils, 5
years for eS/CN Ground Water Plume,
and at least 30 years for UST Source
and Ground Water Plume.
This is an active restoration alternative which includes the
common elements, on-site low temperature thermal treatment of
contaminated CS/CN area soils, and on-site treatment of
contaminated ground water using air stripping technology.
Alternative 11 differs from Alternative 10 only in the method of
treatment of the CS/CN soils.
28
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FIGURE 10. ALTERNATIVE 10 EXTRACTI
WELL LOCATIONS
u>
QO
UtLHD
H ifl9 foa J«»
w nn
-------
Alternative 12
Present Worth Cost: $ 5,311,632
Years to Complete Cleanup: Less than 1 year for CStCN Soils, 13
years for CStCN Ground Water Plume,
and at least 30 years for tJST Source
and Ground Water Plume.
This is an active restoration alternative which includes the
common elements, on-site SVE of the contaminated CStCN soils and
UST source, on-site air sparging of the contaminated ground water
in the UST area, and on-site treatment of contaminated ground
water using air stripping technology.
Alternative 12 is identical to Alternative 6 with the
addition of air sparging in the UST ground water. Air sparging
employed in the UST source area would accelerate removal of
contaminants in the ground water. Air sparging involves
injecting compressed air into the aquifer through sparging wells.
VOCs in the ground water would be transferred from the liquid
phase to the vapor phase and transported to the soils above the
water table (vadose zone). A SVE system would be used to remove
the VOCs from the vadose zone. Extracted vapors would be treated
using an adsorbent system and process residuals would be managed
appropriately at an off-site, RCRA permitted facility.
This ground water extraction system would only recover the
contaminated ground water located on the SMC property. Natural
attenuation processes would eventually restore the uncollected,
contaminated ground water within an estimated 13 year timeframe.
Alternative 13
Present Worth Cost: $ 6,833,135
Years to Complete Cleanup: Less than 1 year for CStCN Soils, 5
years for CStCN Ground Water Plume,
and less than 30 years for UST Source
and Ground Water Plume.
This is an active restoration alternative which includes the
common elements, on-site low temperature thermal treatment of
contaminated CStCN soils, on-site treatment of contaminated
ground water using air stripping technology, and a requirement to
accelerate ground water cleanup through treatment if site ground
water does not meet Safe Drinking Water Standards within 5 years.
Alternative 13 is identical to Alternative 11 except for the
following two differences: 1) treated ground water can be either
discharged to the Elkhorn River subject to a NPDES permit or
reinjected into the aquifer subject to UIC regulations, and
2) ground water cleanup would be accelerated through treatment if
the ground water does not meet Safe Drinking Water Standards
within 5 years from the startup of the ground water extraction
and treatment system.
30
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There does not appear to be a clear advantage for either
discharge option for the treated ground water. Thus, Alternative
13 allows flexibility for the design process.
Based on the computer modelling results for the 5 well
ground water extraction system described in Alternative 10, the
ground water should meet SDWSs within 5 years if the UST and
CS/CN VOC sources are removed completely. The septic tank
removal and the CS/CN soil treatment activities would remove the
soil contamination. However, ground water contamination sources
may remain in these two areas in the form of a non-aqueous phase.
Therefore, within the first five years of operating the ground
water extraction system, data would be available to determine
whether non-aqueous phase sources prevent reaching SDWSs. If
SDWSs are not achieved within the site ground water within five
years, then ground water cleanup would be accelerated through
treatment of the non-aqueous phase sources.
For cost estimating purposes, it was assumed that the
accelerated treatment of ground water would be required at the
five year mark. The air sparging and SVE systems described in
Alternative 12 are technologies capable of accelerating the
ground water extraction system. Thus, air sparging and SVE
systems were used for cost estimating purposes.
ADplicable or Relevant and ADprocriate Regulations (ARARs)
Section 121(d) (2) of CERCLA requires that cleanup actions
conducted achieve ARARs. ARARs are legally enforceable Federal
or State standards, requirements, criteria or limitations. ARARs
are divided into three types: contaminant-specific, location-
specific and action-specific. A CERCLA remedial action is
required to meet the substantive requirements of ARARs for
activities conducted on-site; both substantive and
administrative requirements are required when activities occur
off-site. The following listing includes both State of Nebraska
and Federal ARARs. When both State and Federal ARARs address the
same issue, the more stringent ARAR would apply.
Contaminant-Specific
The federal Safe Drinking Water Act (SDWA) non-zero Maximum
Contaminant Level Goals (MCLGs) and Maximum Contaminant Levels
(MCLs), 40 CPR 141.50 - 141.62 and 40 CFR 141.11 - 141.16, apply
to ground water. Also, The Nebraska Title 118 MCLs apply to
ground water.
The federal Clean Water Act, 33 U.S.C. 1251 et ~.,
criteria for surface water discharges, including but not limited
to section~ 301, 303, 304, 402 and 502 apply to surface water
discharged during site activities. Nebraska Title 117 also
establishes water quality standards which apply to surface waters
31
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discharged during site activities.
Nebraska Title 129 establishes air quality standards which
apply to air emissions released from site remediation activities.
Location-Specific
Due to the location near the Elkhorn River, the remedial
action must meet the substantive requirements of the State's
Floodplain act, Titles 455 and 258.
Nebraska Title 163 applies to the site and requires
consultation with the Nebraska Game and Parks Commission for
activities which may affect threatened or endangered species.
Action-Specific
Alternate
Water Supply
Ground Water
Monitoring
Monitoring,
Supply and
Extraction
Wells
Reinjection
Wells
Discharge
of Ground -
Water to
Elkhorn River
The federal Safe Drinking Water Act, 42 U.S.C.
300{f) et seq.
The Nebraska Safe Drinking Water Act, Neb. Rev.
Stat. ~71-5301 to 71-5313, and implementing regs
found at Title 179 apply.
Municipal and Rural Domestic Groundwater Transfers
Act, Neb. Rev. Stat. ~46-638 to 46-650 applies to
public water supplies.
The substantive ground water monitoring
requirements of RCRA apply as specified in 40
C.F.R. Part 264 or 265, Subpart F and incorporated
in Nebraska Title 128. After removal of the
septic system, the post-closure requirements at 40 .
C.F.R. Part 265, Subpart G and incorporated in
Nebraska Title 128 apply.
The substantive requirements of the State well
registration, standards, licensing requirements
and well spacing requirements apply as specified
in ~ Rev. Stat. ~46-602 et seg., ~46-1201 to
46-1241 (and accompanying regs in Title 178), and
~46-651 to 46-655, respectively.
The substantive requirements of the Nebraska Title
122 and the Federal UIC regulations, issued
pursuant to the SDWA, apply to reinjection of
water or air into the ground.
The substantive and administrative requirements of
Nebraska Titles 119 (NPDES regulations) and 121
(NPDES regulations), and the federal Clean Water
Act, 33 U.S.C. 1251 ~ ~ apply.
32
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Septic
System
Removal
Excavated
Soil
Treatment
Residuals
Low
Temperature
Thermal
Treatment of
Soils
SVE, Air
Sparging and
Air Stripping
Biological
Treatment
The substantive requirements of RCRA
regulations at 40 C.F.R. Part 264 or
Nebraska Title 128 governing closure
closure apply.
RCRA Land Disposal Restrictions (LDRs) 40 C.F.R.
268 apply. The excavated soils would be
potentially classified as D029, D039 and/or D040
characteristic wastes. Substantive requirements
of Nebraska Title 128 apply for transportation
(Chapter 20) and on-site storage (Chapters 16 and
21) .
and the
265, and
and post-
On-site management must conform to the substantive
requirements of RCRA and the regulations at
40 C.F.R. Parts 260 to 299 and Nebraska Title 128.
Offsite management must conform to the substantive
and administrative requirements of RCRA and the
regulations at 40 C.F.R. Parts 260 to 299 and
Nebraska Title 128.
ARARs previously described for air emissions,
excavated soil and treatment residuals apply.
ARARs previously described for air emissions,
extraction wells, injection wells, treatment
residuals and discharge to surface water apply.
ARARs previously described for air emissions,
extraction wells, injections wells, treatment
residuals and discharge to surface water apply.
Performance Standards
Performance standards are technical criteria used in
parallel to ARARs to make decisions during the design and/or
implementation of remedial actions. Performance standards
commonly address issues for which there are no ARARs. The
following list of performance standards apply to the remedial
action options evaluated for the SMC site:
80i1 Restoration Levels
Several treatment options evaluated in the Proposed Plan and
in this ROD address soil contamination. The contaminants of
concern are VOCs in general, and TCE, PCE, 1,1,1-TCA, 1,1-DCE,
1,1-DCA and 1,2-DCA, specifically. The performance standards
used to identify unacceptable concentrations of contaminants in
soil are called soil restoration levels. There are no standard
33
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soil restoration levels which apply to all sites; instead, soil
restoration levels are developed for each site. For the SMC
site, further or continuing contamination of ground water is the
only unacceptable threat due to contaminated soil, as identified
in the baseline risk assessment. As a result, the soil
restoration levels are based on the threat to continued
contamination of ground water above Safe Drinking Water
Standards.
The EPA Organic Leachate Model (OLM), published at 51
Federal Register 27062 (July 26, 1986), was developed to estimate
contaminant concentrations in the leachate from contaminated soil
of known contaminant concentrations. For the SMC site, the OLM
was used in reverse to establish soil restoration levels. The
leachate contaminant concentrations were set at the MCL values to
protect human health. Typically, the OLM incorporates a dilution
effect to account for a small volume of leachate migrating from a
soil source through unsaturated soils to mix with a large volume
of water in the aquifer. However, the dilution effect was not
included for this site since the soil contamination is typically
located within the influence of the ground water table.
The following soil restoration levels presented for certain
site contaminants were developed using the OLM without dilution.
The OLM without dilution would be used to develop soil
restoration levels for all VOC contaminants detected at the site.
Contaminant
Soil Restoration
Level (mq/kq)
Trichloroethylene (TCE)
0.076
Tetrachloroethylene (PCE)
0.227
1,1,1-Trichloroethane (l,l,l-TCA)
2.0
1,1-Dichloroethene (l,l-DCE)
0.084
1,2-Dichloroethane (1,2-DCA)
0.025
The OLM developed restoration level presented above for
1,1,1-TCA was reduced by an order of 10 due to the potential for
1,1,1-TCA to break down naturally to Dichloroethylene and
Dichloroethane compounds. This modification is consistant within
EPA Region 7 at another Nebraska CERCLA site.
The soil restoration levels will apply to the CS/CN and UST
sources. Specifically, treatment actions involving excavation of
soil would extend horizontally and vertically until all soil
above the restoration levels is removed. For those excavation
actions which do not achieve the soil restoration levels,
34
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additional treatment activities 'such as soil vapor extraction
(SVE) may be required. SVE actions would operate until the
contaminated soil is verified to meet the restoration levels.
The EPA recognizes that the OLM method does not account for
site specific information. Also, on a national level, the EPA is
both evaluating the concept of national soil restoration levels
and developing improved methods to calculate soil restoration
levels. As a result, this ROD defines the soil restoration
levels through using the OLM method without dilution. However,
the soil restoration levels may change prior to or during the
design phase of the project if national levels are developed, or
a method to calculate soil restoration levels is developed which
more accurately accounts for site specific information in the
determination of EPA.
Air Emissions
Air emissions will be generated from treatment activities
for both soil and ground water contamination. The Nebraska Title
129 is an ARAR for air emissions for the treatment options. In
addition, the risks associated with the potential exposure to air
emissions will be calculated during the design process and used
to determine the need for air emissions control equipment. The
risk calculations will be conducted in accordance with all
relevant and current EPA risk assessment guidance. The EPA
Industrial Source Complex Short Term or Long Term air dispersion
models (ISCST or ISCLT) will be used to develop the ambient air
concentrations used in the risk calculations. The more stringent
requirements specified in either Title 129.or developed by risk
calculations would apply.
SECTION 8.0
SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
The NCP has established nine criteria to be used to evaluate
remedial alternatives. To select a remedy, each alternative must
be evaluated with regard to these criteria and then be compared
to each other. The selected remedy is the alternative that meets
the threshold criteria and that then provides the best balance of
trade-offs among the remaining criteria in this comparative
analysis.
The nine criteria are divided into three groups:
(1) Threshold Criteria - alternatives which do not satisfy these
criteria are eliminated; (2) Primary Balancing Criteria - these
criteria are used to weigh major trade-offs among alternatives;
and, (3) Modifying Criteria - these criteria are taken into
account after the public comment period.
35
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Threshold Criteria
- Overall Protection of Human Health and the Environment:
Alternative 1, the No Action alternative, would not be
protective of human health and the environment. PMHC and other
properties within the ground water plume would be exposed to
contaminated ground water. Alternative 1 is not considered
further in this analysis.
Alternatives 2 and 3 reduce the risk to human health through
providing an alternate water supply. However, these alternatives
are not protective of human health because the contamination
plumes on and north of the SMC property would not be remediated.
Therefore, risks to human health are reduced but not eliminated.
Alternatives 4 through 13 further reduce the risk to human
health through ground water extraction and treatment in the
contaminated aquifer. Alternatives 4, 5, 6, 7, 8, 9 and 12
employ ground water extraction systems which hydraulically
control the contaminated ground water only on the SMC property.
However, contaminated ground water located north of the SMC
property is not controlled. Risk assessment calculations
indi~ate that the potential exposure to the uncontrolled, north
plume is unacceptable based on EPA criteria.
Alternatives 10, 11 and 13 employ ground water extraction
systems which hydraulically control the entire contaminated
ground water plume, both on and north of the SMC property.
Relative to alternatives 4, 5, 6, 7, 8, 9 and 12, the potential
for exposure to contaminated ground water would be reduced using
the extraction system defined for alternatives 10, 11 and"13.
- Compliance with ARABs:
Title 118 - Ground Water Quality Standards and Use
Classification, requires active restoration of contaminated
ground water to defined cleanup levels. Alternatives 2, 3, 4, 5,
6, 7, 8, 9 and 12 allow for the contaminated ground water north
of the SMC property to go uncontrolled and to naturally
attenuate. NDEQ has stated that Title 118 is consistently
enforced for an entire ground water plume. As a result, the
above listed alternatives do not satisfy Title 118 and are not
considered further in this analysis.
Alternatives 10, 11 and 13 would satisfy the ARARs defined
in Section V, including Title 118.
36
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Balancing Criteria
- Long-Ter.m Effectiveness and Per.manence
Alternatives 10, 11 and 13 address both ground water and
soil contamination on and north of the SMC property. Exposures
to the contaminated media would be effectively controlled through
the provision of potable water meeting SDWSs, hydraulic control
of the contaminated ground water, and, if required, engineering
controls of air emissions. All three alternatives are designed
to permanently restore the soil and aquifer to acceptable levels
based on risk assessment and ARARs.
Addressing the UST source is the major difference between
the three alternatives. Al~ernatives 10, 11 and 13 manage the
UST source through hydraulic control. Thus, the UST source could
continue to leach VOCs to the aquifer for an unknown length of
time. The timeframe to achieve performance standards was assumed
to be 30 years due to cost estimate considerations. The major
difference between the alternatives is that alternative 13
provides for additional treatment activities, if the ground water
in the contaminated ~quifer does not achieve Safe Drinking Water
Standards within five years. Depending on the nature of the UST
source, alternative 13 could achieve the performance standards in
significantly less time than alternatives 10 and 11.
- Reduction of Toxicity, Mobility, or Volume Through Treatment:
Alternatives 10, 11 and 13 reduce mobility and volume of
contaminated ground water by employing ground water extraction
systems which prevent contaminants from migrating and
contaminating additional ground water. Air stripping of
contaminated ground water transfers the VOCs to air. Depending
on performance standards and ARARs, the VOCs may be released to
the atmosphere if performance standards and ARARs are met, or
collected and destroyed if performance standards and ARARs are
exceeded. Destruction of the VOCS would eliminate the toxicity
of the contaminants.
Alternatives 10, 11 and 13 utilize soil treatment
technologies which remove VOCs from the soil. As a result, the
alternatives prevent the transport of VOCs from soil to the
ground water which reduces the volume of contaminated soil and
ground water. Soil vapor extraction and low temperature thermal
treatment used in alternatives 10, 11 and 13 transfer the VOCs
from the soil to air. Depending on performance standards and
ARARs, the VOCs may be either released to the atmosphere if
performance standards and ARARs are met, or collected and
destroyed if performance standards and ARARs are exceeded.
Destruction of the contaminants would eliminate the toxicity.
37
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Alternatives 10, 11 and 13 satisfy the NCP preference for
treatment.
- Short-ter.m Effectiveness
Implementation of alternatives 10, 11 and 13 would result in
low potential for unacceptable short-term risks to human health
and the environment. While soil vapor extraction, low
temperature thermal treatment of soils, excavation of
contaminated soils, air stripping of contaminated ground water,
ground water monitoring and installation of ground water wells
would increase exposure to contamination by workers, all workers
would be protected by use of appropriate personal protective
equipment. During implementation of the cleanup, exposures to
the general public would be controlled by air monitoring and site
access controls.
Environmental impacts associated with these alternatives
would be low. The ground water extraction systems employed by
these alternatives are not expected to negatively impact the
nearby water uses. Air emissions would be monitored and managed
through engineering controls, as appropriate.
- ~lementability
Implementation concerns for alternatives 10, 11 and 13 are
low. The equipment, materials and labor skills are readily
available, and the procedures to be followed are common. Access
agreements would be required with property owners other than SMC
for installation and maintenance of monitoring and extraction
wells. Construction of a pipeline carrying treated ground water
to the Elkhorn River would require extensive coordination and
possible access agreements with local property owners, utilities
and officials. Obtaining the appropriate permits in a timely
manner will require proactive project management.
- Cost
The estimated present-worth cost for alternatives 10, 11 and
13 are $5,771,115, $6,106,337 and $6,833,135, respectively. The
present worth cost estimates include both capital costs and
operation and maintenance costs. The operation and maintenance
costs assume that ground water extraction and treatment would be
operated for 30 years, even though the extraction systems would
be designed to clean the aquifer within five years. In addition,
the cost estimate for alternative 13 assumes the worst case
scenario by including the cost for accelerating the ground water
cleanup. As a resul~, actual costs are expected to be lower than
the estimates presented.
38
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Modifying Criteria
- State Acceptance
The Nebraska Department of Environmental Quality (NDEQ) ,
representing the State of Nebraska, has notified EPA of its
concurrence with the selected remedy. A copy of the State's
concurrence letter is presented following the Declaration.
- Community Acceptance
The reservations, concerns, and supporting or opposing
comments of the community on the RI/FS, the Proposed Plan, and
other information in the Administrative Record were made known to
the EPA during the thirty day comment period and the public
meeting with the community on August 31, 1993. There have been
no comments which required EPA to change the Preferred
Alternative identified in the Proposed Plan. The public's
comments are addressed in the responsiveness summary, which is a
component of this Record of Decision for the site.
SECTION 9.0
THE SELECTED REMEDY
The EPA has determined that the selected remedy for the SMC site
is Alternative 13. This selected remedy will provide overall
protection of human health and the environment by eliminating,
reducing or controlling all current and potential risks posed by
the exposure pathways at the site, and will be in compliance with
all Applicable or Relevant and Appropriate Requirements (ARARs).
Long-Term Effectiveness and Permanence of the selected remedy
were determined to be critical factors in balancing the trade-
offs among the alternatives. The selected remedy includes:
'*
A deed restriction to prohibit land disturbance at the
UST and CS/CN areas after excavation and the use and
installation of ground water supply wells in the
contaminated portion of the aquifer on the SMC
property;
Potable water, meeting SDWSs, provided to the PMHC and
other properties located within the contaminated ground
water aquifer, or unacceptably threatened by it;
'*
'*
A ground water monitoring program to monitor and
evaluate changes in ground water quality throughout
both plumes, both on and off the SMC property;
'*
The removal of the UST, the concrete settling basin,
and the septic tank from the UST area. 50il samples
will be collected and analyzed to determine whether a
soil source of ground water contamination exists in the
39
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area. Treatment measures will be implemented to
address soils contaminated above soil restoration
levels specified in Section 7.0. Selection of the
treatment method(s) will be consistent with the
Feasibility Study;
*
Excavation and low-temperature thermal treatment of
contaminated CS/CN soils which exceed the soil
restoration levels specified in Section 7.0. Soil
excavation in the CS/CN area will not be required below
the clay unit. However, treatment measures will be
implemented if soils left below the clay unit exceed
the soil restoration levels. Selection of the
treatment method(s) will be consistent with the
Feasibility Study;
*
A ground water extraction and treatment system which
will hydraulically control the entire CS/CN and UST
source area ground water plumes, including the
contaminated ground water on and north of the SMC
property. As a minimum, the extraction system will
include ground water extraction wells located in the
UST area, the CS/CN area, the area in which monitoring
well cluster 7 is located, and the property located
north of the SMC property. The extraction system will
be designed to achieve Safe Drinking Water Standards
(SDWSs) throughout the contaminated aquifer within five
years. Air stripping technology will be used to treat
the extracted, contaminated ground water. The treated
ground water may be discharged to either the Elkhorn
River or reinjected into the aquifer; and,
*
If the ground water does not meet SDWSs within five
years fram the startup of the ground water extraction
and treatment system, the ground water cleanup will be
accelerated through modifying and/or augmenting the
original treatment system using additional treatment
technologies. Selection of the additional treatment
technologies will be consistent with the Feasibility
Study.
The ARARs and Performance Standards listed in Section 7.0
apply to the appropriate treatment technologies and remedial
actions included in the selected remedy.
The EPA will conduct a five-year site review, consistent
with the standards set forth in Section 121(c) of CERCLA, 42
U.S.C. 9621(c).
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SECTION 10.0
STATUTOR.Y DETERMINATIONS
The remedial actions selected for implementation at the
Sherwood Medical Company site are consistent with CERCLA and not
inconsistent with the NCP. The selected remedy is protective of
human health and the environment, attain ARARs, and are cost-
effective. The selected remedy also satisfies the statutory
preference for treatment which permanently and significantly
reduces the toxicity, mobility, or volume of hazardous substances
as a principle element.
The selected remedy for the site will address the release or
threat of release posed by the contaminated soils and ground
water. The selected remedy is thereby protective.
The soil restoration levels to be attained through
excavation and onsite low temperature treatment will reduce the
risks associated with the soil acting as a source for further
contamination of the ground water.
The extraction and onsite treatment of the ground water will
assure that the cleanup levels established for the site are met.
These cleanup levels are the Federal Safe Drinking Water
Standards and the Nebraska Title 118 MCLs.
The selected remedy will meet or attain all Federal and
State ARARs that apply to the site. The ARARs are identified in
Section 7.0.
SECTION 11.0
DOCUMENTATION OF SIGNIFICANT CHANGES
There were no significant changes made to the Proposed Plan
in this Record of Decision.
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APPENDIX A
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GLOSSARY
EPA used the following nine criteria, as specified in the
National Contingency Plan ("NCP"), to evaluate alternatives
identified in the FS. While overall protection of public health
and the environment is the primary objective of the remedial
action, the remedial alternative(s) selected for the Sherwood
Medical Company site must achieve the best balance among these
evaluation criteria considering the scope and relative degree of
contamination at the site.
1. Overall Protection of Human Health and the Environment - - in
order for an alternative to be considered, it must evaluated to
determine if it adequately protects human health and the
environment, in both the short and long-term, from unacceptable
risks posed by hazardous substances, pollutants, or contaminants
present at the site by eliminating, reducing, or controlling
exposures to levels established during development of remediation
goals.
2. Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) -- in order for an alternative to be
considered, it must be assessed to determine if it attains ARARs
under Federal environmental law and State environmental or
facility siting laws or provide grounds for invoking a statutory
waiver pursuant to CFR 300.430(f) (1) (ii) (C).
3. Long-Ter.m Effectiveness and Per.manence -- each alternative
must be assessed to evaluate its ability to maintain reliable
protection of human health and the environment over time once the
cleanup goals have been met.
4. Reduction of Toxicity, Mobility, or Volume -- These are the
three principal measures of the overall performance of an
alternative. The 1986 amendments to the Superfund statute
emphasize that, whenever possible, EPA should select a remedy
that uses a treatment process to permanently reduce the level of
toxicity of contaminants at the site; the spread of contaminants
away from the source of contamination; and the volume or amount
of contamination at the site.
5. Short-Ter.m Effectiveness -- each alternative must be
evaluated to assess the likelihood of adverse impacts on human
health or the environment that may be posed during the
construction and implementation of an alternative until the
cleanup goals are achieved.
6. ~lementability. -- each alternative must be evaluated to
determine whether it is feasible, technically and admin-
istratively. The availability of materials and service needed to
implement the alternative are a part of this assessment.
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7. Cost -- estimates are developed for the cost of implementing
an alternative, as well as the cost of operating and maintaining
the alternative over the long term, and the net present worth of
both the capital and operation and maintenance costs.
8. State Acceptance -- addresses whether, based on its review of
the RI/FS and Proposed Plan, the State concurs with, opposes, or
has no comments on the alternative EPA has chosen as the remedy
for the site.
9. Community Acceptance -- addresses whether the public
with EPA's chosen alternative. Community acceptance was
evaluated based on comments received during the upcoming
meeting and during the public comment period.
concurs
public
Terms Used in the Record of Decision
Administrative Order CAO): A legal and enforceable agreement
signed between EPA and Potentially Responsible Parties (PRPs)
whereby the PRPs agree to perform or pay for the cost of site
response actions. The agreement describes actions to be taken at
a site.
Applicable or Relevant and Appropriate Requirements CARARs):
ARARs include any State or Federal statute or regulation that
pertains to protection of public health and the environment in
addressing certain site conditions or using a particular cleanup
technology at a Superfund site. Nebraska's ground water
protection policy is an example of an ARAR. EPA must consider
whether a remedial alternative meets ARARs as part of the process
for selecting a cleanup alternative for a Superfund site.
Aquifer: A layer of rock or soil that can
ties of ground water to wells and springs.
source of drinking water and provide water
well.
supply usable quanti-
Aquifers can be a
for other uses as
Carbon adsorption: A treatment system in which contaminants are
removed from ground water or surface water by forcing water
through tanks containing granular activated carbon, a specially
treated material that attracts and binds the contaminants.
Comprehensive Environmental Response, Compensation, and Liability
Act CCERCLA): A Federal law passed in 1980 and modified in 1986
by the Superfund Amendments and Reauthorization Act (SARA). The
acts created a special tax that goes into a Trust Fund, commonly
known as Superfund, to investigate and clean up abandoned or
uncontrolled hazardous waste sites. Under the program, EPA can
either: 1) pay for site cleanup when parties responsible for the
contamination cannot be located or are unwilling or unable to
perform the work; or, 2) take legal action to force parties re-
sponsible for site contamination to clean up the site or pay back
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the Federal Government the cost of the cleanup.
Contaminants of Potential Concern (COPCs): Contaminants,
identified during the site investigations and risk assessments,
that pose a potential risk because of their toxicity and
potential routes of exposure to public health and the
environment.
Downgradient: Downstream from the flow of ground water. The
term refers to ground water flow in the same way that it does to
a river's flow.
Safe Drinking Water Standards: Safe Drinking Water Standards
(SDWSs) for human ingestion specified in both the Federal Safe
Drinking Water Act (SDWA) and the Nebraska Title 118.
Ground water: Water, filling spaces between soil, sand, rock and
gravel particles beneath the earth's surface, that often serves
as a source of drinking water.
Max~um Contaminant Levels (MCLs): The maximum permissible level
of a contaminant in water that is or may be consumed as drinking
water. These levels are determined by EPA and are applicable to
all public water supplies.
Migrate:
To move from one area to another; to change location.
Monitoring Wells: Special wells installed at specific locations
on or off a hazardous waste site where ground water can be sam-
pled at selected depths and studied to determine such things as
the direction in which the ground water flows and the types and
concentrations of contaminants present.
National Contingency Plan (NCP):
guides the Superfund program.
The Federal regulation that
Present Worth: The amount of money necessary to secure the
promise of future payment or series of payments at an assumed
interest rate.
Operation and Maintenance (OMK): Activities conducted at a site
after response actions occur, to ensure that the cleanup or
containment system continues to be effective.
Organic Compounds: Chemical compounds composed primarily of
carbon and hydrogen, including materials such as oils, pesti-
cides, and solvents.
Parts per Billion (ppb): A unit of measurement used to describe
levels of contamination. For example, one gallon of a solvent in
one billion gallons of water is equal to one part per billion.
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Parts per ~llion (ppm): A unit of measurement used to describe
levels of contamination. For example, one-half pound of
contaminant in 250 tons of soil is equal to one part per million.
Potentially Responsible Parties (PRPs): Any individual(s) or
company(s), (such as owners, operators, transporters, or genera-
tors) who are potentially responsible for the contamination
problems at a Superfund site. Whenever possible, EPA requires
PRPs, through administrative and legal actions, to clean up a
hazardous waste site.
Resource Conservation and Recovery Act (RCRA): RCRA is a Federal
law that regulates the transportation, storage, treatment, and
disposal of hazardous wastes.
Remedial Alternatives: The technology, or combination of tech-
nologies, used by EPA in treating, containing, or controlling
contamination at a Superfund site. A remedial alternative can
address soil, sediments, and/or ground water contamination.
Remedial ~nvestigation/Peasibility Study (R~/PS): A two-part
study that determines the nature and extent of the problem pre-
sented by the release and evaluates the options available for
remedial action. The Remedial Investigation (RI) emphasizes data
collection and site characterization and is typically performed
concurrently with the Feasibility Study (FS). The FS emphasizes
data analysis in conjunction with technologies available for
consideration as remedial alternatives.
Sed~ents: The sand or mud found at the bottom and sides of
bodies of water such as creeks, rivers, streams lakes, swamps,
and ponds. Sediments typically consist of relatively small soil
particles (such as silt, clay, or sand) and organic (plant) mat-
ter. Gravel sized particles are sometimes included, as well.
Solvents: Liquids capable of dissolving other liquids or solids
to form a solution. The chief uses of industrial solvents are as
cleaners and degreasers. Solvents are also used in paints and
pharmaceuticals. Many solvents are flammable and toxic to vary-
ing degrees.
Toxicity: A measure of the degree to which a substance is
harmful to human and animal life.
Upgradient: This term refers to the direction of ground water
flow in the same way that the term upstream refers to a river's
flow.
VOCs: VOCs is an acronYm for Volatile Organic Compounds. VOCs
are a clas~of organic chemicals which tend to evaporate at
normal atmospheric conditions.
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