PB96-964302
EPA/ROD/R07-96/083
November 1996
EPA Superfund
Record of Decision:
Cleburn Street Well Site,
Grand Island, NE
6/7/1996
-------
-------
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VII
726 MINNESOTA AVENUE
KANSAS CITY, KANSAS 66101
JUNTO 1996
SUBJECT: Record of Decision for Cleburn Street Well
Superfund Site
FROM: Michael J. Sanderson
Director, Superfund
TO: Dennis Grams, P..E.
Regional Administrator
I am submitting for your approval the attached Record of
Decision (ROD) for the Cleburn Street Well Superfund site in
Grand Island, Nebraska. I have reviewed the package and
recommend your approval of the ROD. Please indicate your
approval by signing the ROD Declaration.
This ROD presents the selected remedy to address soil and
groundwater contamination at three source areas of the Cleburn
Street Well Superfund site. The site consists of groundwater and
soils contaminated with volatile organic compounds (VOCs),
primarily tetrachloroethylene, commonly called PCE.
A public hearing was held on February 27, 199-6, to present
the preferred remedy to the public and to receive feedback
regarding public acceptance of the remedy. No public comments
were received in opposition to the preferred alternatives, which
indicates that the public is generally supportive. The Nebraska
Department of Environmental Quality (NDEQ) has also indicated its
support for the selected remedy. The Region 5/7 Accelerated
Response Center in the Office of Emergency and Remedial Response
provided consultation in the development of the proposed plan and
ROD, and supports the selected remedial alternatives.
If you have questions or concerns regarding the selected
remedy, please contact me or Mary Peterson, the project manager,
at extension 7882.
Attachment
cc: Anne Pamperl, NDEQ
RECYCLED
WPW CONTJUNS RECYCLED FBERS
-------
-------
RECORD OF DECISION DECLARATION
SITE NAME AND LOCATION
Cleburn Street Well Site
Grand Island, Nebraska
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial actions for three separate source areas at the Cleburn
Street Well Site in Grand Island, Nebraska. The remedies have been 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, to the extent practicable, with
the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the
administrative record for the site.
The Nebraska Department of Environmental Quality is in agreement with the selected remedies.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by implementing the
selected remedial actions presented in this Record of Decision (ROD), may present an imminent and
substantial endangermentto public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
The selected remedies are final actions for three separate source areas at the site, with a contingency action
included in the remedies for two of the source areas. The selected remedies address contaminated
groundwater and subsurface soils according to the extent of contamination and associated risks at each source
area. The overall remedial objective is restoration of the shallow aquifer to its designated use as a drinking
water source.
The primary source area is the former One Hour Martinizing dry cleaning facility which contains high levels of
volatile organic compounds (VOCs), primarily tetrachloroethylene (PCE), in the shallow groundwater and
subsurface soils. The selected remedy for this source area includes the following components:
In-situ soil treatment by soil vapor extraction and treatment by carbon adsorption;
Groundwater extraction and treatment by on-site air stripping;
Institutional controls to restrict groundwater use and prevent exposures;
Groundwater monitoring; and
Air monitoring of emissions from the air stripper and emissions controls if necessary.
Institutional controls and groundwater monitoring were not presented as part of the preferred remedy for
groundwater at the One Hour Martinizing source area in the proposed plan. However, they were included in
the discussion and evaluation of the selected alternative in the feasibility study and were also presented as
separate alternatives in the proposed plan.
-------
The other two source areas are the Liberty Services and Ideal Cleaners dry cleaning facilities, which are
currently operating. Contamination at both of these facilities consists of low levels of VOCs, primarily PCE, in
the shallow groundwater and subsurface soils. The selected remedy for each of these source areas includes
the following components:
•• Natural attenuation and groundwater monitoring for ten years;
•• Institutional controls to restrict groundwater use and prevent exposures; and
» Contingency action: In-situ treatment of source soils by soil vapor extraction and carbon
adsorption.
STATUTORY DETERMINATIONS
The selected remedies are protective of human health and the environment, comply with Federal and state
requirements that are legally applicable or relevant and appropriate to the remedial actions, and are cost-
effective. The selected remedy for the One Hour Martinizing source area utilizes permanent solutions and
alternative treatment technologies to the maximum extent practicable, and satisfies the statutory preference
for treatment as a principal element. The selected remedy for the Liberty Services and Ideal Cleaners source
areas utilizes permanent solutions to the maximum extent practicable, but only calls for treatment as a
contingency action and not a principal element. Because the remedies will result in hazardous substances
remaining onsite, EPA will conduct a review of the adequacy of the selected remedies no less often than every
five years as required by Section 121 of SARA.
'— Dennis Grams .
Regional Administrator
-------
TABLE OF CONTENTS
for the
RECORD OF DECISION
Cleburn Street Well Site
Grand Island, Nebraska
1. SITE NAME, LOCATION, AND DESCRIPTION 2
2. SITE HISTORY AND ENFORCEMENT ACTIVITIES 3
3. HIGHLIGHTS OF COMMUNITY PARTICIPATION 4
4. SCOPE AND ROLE OF THE RESPONSE ACTION 5
5. SUMMARY OF SITE CHARACTERISTICS 5
6. SUMMARY OF SITE RISKS 8
7. DESCRIPTION OF REMEDIAL ALTERNATIVES 10
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES .... 18
9. SELECTED REMEDY 27
10. STATUTORY DETERMINATIONS 33
11. DOCUMENTATION OF SIGNIFICANT CHANGE 36
RESPONSIVENESS SUMMARY 37
-------
-------
RECORD OF DECISION
DECISION SUMMARY
Cleburn Street Well Site
Grand Island, Nebraska
April 1996
1.
SITE NAME, LOCATION, AND DESCRIPTION
The Cleburn Street Well site is located in Grand Island, Hall County, Nebraska and is situated approximately
two miles north of the Wood River and approximately seven miles northeast of the Platte River. The Cleburn
Street Well site encompasses a portion of the downtown area, and is surrounded by a variety of light industries,
commercial businesses, and residential dwellings.
Grand Island
CLEBURN ST.
WELL SITE
Figure 1 - Site Location
The site is located in the Great Plains physiographic
province and in the middle of the Platte River Basin.
Surface topography is generally flat with natural surface
drainage flowing in a northeasterly direction. Much of the
surface water runoff from the site is controlled by man-
made features such as storm sewers and gutters. The
Platte River flows from southwest to northeast and is
situated approximately seven miles south of Grand Island.
Groundwater flows in a northeasterly direction in the vicinity
of the site.
The Cleburn Street Well site consists of a former municipal
water supply well, the Clebum Street well, and surrounding
groundwater and soils containing volatile organic
compounds (VOCs), primarily tetrachloroethylene (PCE).
Results of the remedial investigation (Rl) completed in
1993 indicate four separate source areas including three
dry cleaning facilities and a former solvents distribution
facility. This ROD addresses the three dry cleaning source
areas only. The solvents facility source area will be
addressed in a separate ROD following additional
investigation. Figure 2 below shows the location of all four
source areas.
The three dry cleaner source areas which are the subject of this ROD include the former One Hour Martinizing
facility, the Liberty Services facility, and the Ideal Cleaners of Grand Island facility. Results of the Rl indicate
that the primary source area responsible for contamination of the Cleburn Street municipal well is the former
One Hour Martinizing facility. Extremely high contaminant levels were found in the shallow subsurface soils
and groundwater in the vicinity of this facility. The Liberty Services and Ideal Cleaners source areas exhibit
lesser degrees of contamination and are not believed to be related to contamination of the Cleburn Street well.
-------
2. SITE HISTORY AND ENFORCEMENT ACTIVITIES
Contamination in the Cleburn Street well was first discovered in March 1986 when the Nebraska Department
of Health (NDOH) detected PCE at a concentration of 21.9 micrograms per liter (ug/l). The NDOH resampled
the well in April 1986 following a citizen's complaint of poor taste and odor in the municipal drinking water, and
confirmed the presence of PCE at a concentration of 26.9 ug/l. The Cleburn Street well was subsequently
closed for drinking water purposes.
Since 1986, the city has continued to operate the Cleburn Street well for the purpose of alleviating flooding
problems in the nearby Eddy Street railroad underpass. Until September 1992, groundwater pumped from the
Cleburn Street well was discharged to the city storm sewer for direct discharge to the Wood River. In early
1993, the city, with approval from the NDEQ, redirected discharge of the groundwater to the city's sanitary
sewer for treatment in the wastewater treatment plant called the Publicly Owned Treatment Works (POTW).
In 1988, EPA conducted a soil-gas survey to identify potential sources of the PCE contamination. Based on
the findings of the soil gas survey and previous sampling events, the Cleburn Street Well site was proposed
for the National Priorities List (NPL) on July 29,1991. Listing of the Cleburn Street Well site was finalized on
October 14,1992.
Between 1990 and 1992, EPA conducted a search for potentially responsible parties. A series of CERCLA
Section 104(e) information request letters was sent to several parties associated with potential sources
identified during the soil gas investigation. Responses to these information requests helped refine the list of
potential sources. At the conclusion of the PRP search, the owner and former operator of the One Hour
Martinizing facility were determined to be potentially liable for cleanup of the contamination stemming from that
source area. However, the former operator was insolvent and was not issued a CERCLA notice of potential
liability. A special notice letter was issued to the property owner who had leased the property to the operators
of the One Hour Martinizing facility. The property owner did not have sufficient funds to contribute toward
investigation and cleanup of the property, and EPA initiated a fund-lead RI/FS. Notice letters were not sent to
the owners/operators of other sources because there was no information indicating that any facility other than
One Hour Martinizing contributed to contamination of the Cleburn Street well.
The RI/FS began in 1992 to define the nature and extent of contamination. The first phase of the Rl for this site
was conducted in May 1992 and consisted of the installation of several groundwater monitoring wells at all of
the potential source areas, arid the collection of numerous groundwater and soil samples. In addition, a cone
penetrometer survey consisting of the collection of discrete grouridwater samples from small, temporary
boreholes was conducted. Results of the Phase I Rl revealed four primary source areas and further revealed
them to be separate and distinct areas of contamination. Only one source area, the former One Hour
Martinizing facility, appeared to be directly relatedto contamination of the Cleburn Street well. After evaluating
the data from the Phase I Rl, EPA decided to focus the remainder of the RI/FS on the three dry cleaner source
areas as follows:
1) former One Hour Martinizing;
2) Liberty Cleaners and Shirt Launderers; arid
3) Ideal Cleaners of Grand Island.
The Rl and FS reports found in the Administrative Record pertain only to the three dry cleaner source areas.
-------
"fia
6th STREET
^UBERTy^UANEBi
jOO
jHnnan]
aCUCJuI]
STREET
MARTOtiziNa '
FORMER NEBRASKA
I SOLVENT COMPANY =
3RD
STREET
2ND STREET
1ST STREET
en
en
en en en
CLEBURN STREET WELL
UNION PACIFIC RAILROAD
BBBBBBB
BBBBBBBB
ingai 01 CAKICPC
I '- I
- I i I
Figure 2 - Location of Source Areas
for the former Nebraska
h0nvtUCte,d' EPA began 3 n°n time-critical «moval action to contain the
nr . by extracting groundwater from around the former One Hour Martinizina
source area. This acton was taken to prevent the contamination from impacting downgradient municipal water
and an S^t ^T**?" fr°m ^ EPA prepared an engineering e^luatonAxi aSSpES)
and an Action Memorandum to support the removal action. The removal action consisted of the instaNarJon
of one groundwater extraction well at the One Hour Martinizing source area and "nn^dton ^^f the dtcharae
piping to the c,ty sanitary sewer. With approval from the city and NDEQ, groundwater fr
-------
public for a thirty day comment period starting on February 15,1996. A formal public hearing was held on
February 27, 1996 to present the proposed plan to the public. The administrative record for the site is
maintained at the local library. In general, community interest in the site can be characterized as low.
4. SCOPE AND ROLE OF THE RESPONSE ACTION
This decision document represents the final remedies for three of the four source areas at the site. A separate
Record of Decision for the fourth source area will be completed following additional investigation needed at that
source area. The remedies called for by this ROD are final actions for each of the three source areas, with
provisions to accommodate either of the following situations:
• It is determined that the remediation goals can not be reasonably achieved in areas found to
contain DNAPL around the former One Hour Martinizing source area.
• The processes of natural attenuation are not effectively protecting human health and the
environment at Liberty and Ideal Cleaners source areas.
In the first situation, the provision would involve waiving the cleanup goals as applicable or relevant and
appropriate requirements (ARARs) based on the technical impracticability of achieving the goals in specific
areas of the plume. This would be done through the use of a Technical Impracticability (Tl) waiver which would
document that it is not technically feasible to achieve remediation goals in areas of the plume containing
DNAPL.
In the second situation, the contingency would involve a treatment component at these two source areas to
address subsurface soils. The contingency remedial alternatives for Liberty and Ideal Cleaners are discussed
later in this document.
5. SUMMARY OF SITE CHARACTERISTICS
Site geology is consistent across the site and is comprised of silty sands to a depth of approximately 90 feet
below ground. This zone comprises the single aquifer (water-bearing) unit in the vicjnity of the site and serves
as the source of municipal drinking water for approximately 33,000 residents of Grand Island. Depth to
groundwater averaged between 18-22 feet below ground surface during the Rl. Depth to the clay aquitard unit
was encountered between 87 feet and 94 feet below ground surface. Groundwater flow in the vicinity of the
site is in a northeasterly direction.
Soil Characteristics
Chemical analysis of soil samples collected from soil borings and monitoring well borings indicated the
presence of tetrachloroethylene (PCE) and compounds commonly associated as potential degradation
products of PCE, trichloroethylene (TCE), 1,2-dichlbroethylene, and 1,1,1 - trichloroethane at each of the three
source areas. Other compounds commonly associated as potential minor degradation products, 1,1-
dichloroethylene and 1,1,2-trichloroethane were also detected at the three source areas.
PCE is the primary contaminant of concern and was detected at the former One Hour Martinizing, Liberty
Cleaners, and Ideal Cleaners source areas. The highest concentration of PCE (9,200,000 micrograms per
kilogram (ug/kg)) was detected in a soil sample collected from the former One Hour Martinizing source area.
Soil samples collected from Liberty and Ideal Cleaners source areas contained up to 110 ug/kg and 270 ug/kg
PCE, respectively. EPA's soil screening level for PCE is 12,000 ug/kg. As confirmed by the baseline risk
assessment, soil contamination at the Liberty Services and Ideal Cleaners source areas was not found to be
significant source of risk to human health. The maximum PCE concentrations found in soil at each source area
is shown on Table 5-1.
-------
The high PCE concentrations found in soils at the former One Hour Martinizing source area prompted a Phase
3 investigation to further define the horizontal and vertical extent of PCE soil contamination at that source area.
PCE concentrations ranged from non-detectto approximately 11,000,000 ug/kg detected at the 1-3 foot depth.
Concentration levels vary both horizontally and vertically across the source area with the highest PCE
concentrations emanating from the northeast side of the former One Hour Martinizing facility, possibly indicating
a point of origin. Specific details of the soil sampling investigation are presented in the Phase III Addendum to
the Rl report (Sverdrup 1993).
Groundwater Characteristics
During the Rl, the groundwater at each of the three source areas addressed by this ROD was investigated by
the installation of monitoring wells and subsequent groundwater sampling. PCE was detected at concentrations
exceeding the MCL in groundwater samples collected from each source area. The highest concentration of
PCE (170,000 ug/l) was detected in the groundwater sample collected from the former One Hour Martinizing
source area. Compounds commonly associated with the natural degradation of PCE in the environment such
as TCE, 1,2-dichloroethylene (1,2-DCE), and 1,1,1-trichloroethane were also detected in groundwater samples
at maximum concentrations of 410 ug/l, 85 ug/l, and 540 ug/l respectively.
The solubility of PCE in water is 150,000 ug/l. Given that the PCE concentrations found at the former One Hour
Martinizing source area exceed the solubility of PCE in water, the presence of DNAPL is likely, but was not
confirmed during the Rl.
Groundwater at Liberty Cleaners and Ideal Cleaners source areas was contaminated to a lesser degree than
at the former One Hour Martinizing source area. The highest PCE concentrations detected at Liberty Cleaners
and Ideal Cleaners source areas were 65 ug/l and 95 ug/l respectively. Only one other compound which may
be associated with the natural degradation of PCE, 1,1,1-trichloroethane, was found at a concentration of 2 ug/l
at Ideal Cleaners source area. None of the common PCE degradation products mentioned above were
detected at Liberty Cleaners source area. The maximum PCE concentrations detected during the Rl in
groundwater at each of the source areas is shown on Table 5-1.
Table 5-1
Maximum PCE Concentrations
Source Area
One Hour Martinizing
Liberty Services
Ideal Cleaners
Soil (mg/kg)
11,000
0.11
0.27
Groundwater (ug/l)
170,000
65
95
-------
The horizontal and vertical extent of PCE contamination originating from the One Hour Martinizing source area
was estimated, based on Phase III field investigation data. The data is presented on iso-concentration maps
in the Phase III Addendum to the Rl report (Sverdrup, 1993). One of the maps showing the contours of the PCE
plume in the shallow groundwater in the vicinity of the former One Hour Martinizing source area is included here
as Figure 3.
Restrictions to the lateral spread of groundwater contamination may be due to the limited withdrawal of
groundwater from the Cleburn Street well and from the extraction well installed during EPA's removal action
which is exerting some hydraulic control over the plume.
During the Rl, the quality of the groundwater produced from the municipal wells in the vicinity of the site was
evaluated through the collection of groundwater samples from the Cleburn Street well, the Lincoln Street well,
and the Pine Street well. The Pine Street reservoir was also sampled during Phase I. The highest
concentration of PCE was detected in the Cleburn Street well at 19,000 ug/l. Common degradation products,
TCE and 1,1,1- TCA, were detected in the Cleburn Street well below regulatory levels. The Cleburn Street
well is presently not connected to the public water distribution system, and is pumped periodically to control
seepage into the Eddy Street underpass. All water produced from the Cleburn Street well is discharged to the
POTW via the sanitary sewer.
During the Rl, groundwater samples collected from the Lincoln Street well did not contain any VOCs above their
detection limits. A more recent sample collected in May 1994 in connection with the ongoing removal action
showed PCE at a concentration of 12 ug/l in the Lincoln Street well. Both the NDEQ and the city of Grand
Island were notified that this level exceeds the Maximum Contaminant Level (MCL), of 5 ug/l for PCE. MCLs
are established under the Safe Drinking Water Act and represent the maximum concentration of a contaminant
which is considered safe for human consumption.
Figure 3
LEGEND
MONITORING WCLLC
1
pee CONTOUR
lie"
OH IN
-------
6. SUMMARY OF SITE RISKS
EPA prepared a baseline risk assessment using the data collected during the Rl as well as other available
information. The complete baseline risk assessment is found in Volume II of the Rl Report (Sverdrup 1993).
During the early phases of the baseline risk assessment, EPA decided not to conduct an ecological assessment
due to the absence of sensitive ecosystems or habitats in the vicinity of the site.
Contaminant Identification
Any VOC detected at least once in groundwater or soil was identified as a chemical of concern (COC). In all,
18 COCs were identified and included in the assessment of human health risks. A summary of the COCs
including the frequency of detection and the range of concentrations in surface soil, subsurface soil, and
groundwater using data from the Phase 1 and Phase 2 Rl is depicted in Appendix A.
Exposure Assessment
Potential exposure pathways exist for groundwater, soil, and indoor air. It is not believed that any residents are
currently exposed to groundwater or soil directly. However, residents living very near the One Hour Martinizing
source area may be exposed to contaminants in indoor air which may have infiltrated through basement walls
from subsurface soil contamination. Current groundwater exposures are not likely because all city residents
have access to city water and are not known to be using private wells. All soil contamination is below ground
and is therefore not accessible for direct contact exposures.
Although residents are not believed to be currently exposed to contamination, several potential exposure
pathways exist. Future residents could be exposed to contaminated groundwater via ingestion, inhalation, and
direct contact if private wells were installed and used in place of city water. Future development of the One
Hour Martinizing property could also result in direct contact, ingestion, and inhalation exposures to
contaminated soils.
Reasonable Maximum Exposure (RME) scenarios are developed using not only current exposure pathways
given existing land uses, but also exposures which might reasonably be predicted based upon expected or
logical future land use assumptions. The RME scenarios for the three source areas addressed in this ROD
include exposures which may not currently exist. The exposure routes associated with the RME include
ingestion (by drinking), inhalation (by breathing contaminated vapors released during showering and other
household activities), and dermal (skin) contact (by bathing arid other household activities). EPA believes such
exposures are reasonable and may occur.
EPA has no information that anyone in Grand Island is currently drinking the shallow groundwater. The Pine
Street well remains connected to the public water distribution system, and while it has not yet shown
contamination at levels of concern, it is downgradient of the contaminant plume. In addition to the Pine Street
well, private wells could also serve as a source of groundwater to residents of Grand Island. Historically, the
city of Grand Island has not required registration of private wells and has no information regarding the existence
of such wells in the vicinity of the site. Since 1992, registration of all private water wells has been required in
the state of Nebraska per Title 456. However, given the lack of historical registration requirements and the
shallow depth to groundwater, it is reasonable to assume that a resident could install a private well and use it
for drinking water or other household purposes.
The conceptual site model developed during the BRA is included for reference as Appendix B.
-------
Toxicitv Assessment
While 18 COCs were identified and included in the quantification of risks in the BRA, the majority of excess
cancer risks were shown to be attributable to 2 of the 18 COCs: tetrachloroethylene (PCE) and trichloroethylene
CTCE).
Some of the non-carcinogenic health effects commonly associated with exposure to PCE include headaches,
dizziness and other signs of central nervous system depression, and liver damage. Regarding the carcinogenic
effects of PCE, EPA classifies PCE as a B2 probable human carcinogen. Studies of cancer in humans exposed
to above-average levels of PCE have either been ambiguous or negative. However, animal studies reveal
potential carcinogenic effects in the form of hepatocellular carcinomas and renal tumors.
Non-carcinogenic health effects associated with exposure to TCE include effects on the central nervous system,
liver, kidney, and hematological system. Numerous cases of human fatality from oral intake of TCE have been
reported in literature. Acute oral intake of 1,043 mg/kg has been reported as the fatal dose for humans. With
regard to carcinogenic effects associated with TCE exposures, human studies do not provide clear evidence
of a causal relationship between TCE exposure and increased risk of cancer. However, EPA classifies TCE
as a B2 probable human carcinogen due to animal studies which indicate carcinogenic effects in mice and rats.
Inhalation and/or oral exposure resulted in lung and liver tumors in mice and kidney and testicular tumors in
rats.
Risk Characterization
The BRA evaluated the potential carcinogenic and non-carcinogenic risks posed by the COCs in the various
exposure media at the site. An explanation and summary of the carcinogenic and non-carcinogenic risks
characterized in the BRA are presented below. Table 6-1 also summarizes the excess cancer and non-cancer
risks for each of the source areas. The values shown on Table 6-1 represent the sum of the individual
exposure pathway risks evaluated for groundwater and soil exposures. More detailed information on the risks
associated with the individual exposure pathways is found in the BRA.
Carcinogenic Risks:
Excess lifetime cancer risks are determined by multiplying an intake level with the lifetime cancer potency
factor. These risks are expressed as probability values in scientific notation (e.g., 1x10"6). An excess lifetime
cancer risk of 1 x1 Q~* indicates that, as a plausible upper bound, an individual has a one in one million chance
of developing some type of cancer as a result of site-related exposure to a carcinogen over a 70-year lifetime
under the specific exposure conditions at the site.
Use of contaminated groundwater from the One Hour Martinizing source area presents the highest estimated
excess cancer risk of 2x10"1 or 2 in 10. This risk includes all exposure pathways associated with drinking water
including ingestion, inhalation, and dermal contact. The carcinogenic risk associated with exposures to soil at
the former One Hour Martinizing source area is 2x10"7 or 2 in 10,000,000. The cumulative excess cancer risk
for the RME at this source area is 2x10"1 or 2 in 10. The carcinogenic risks associated with exposures to soil
at Liberty Cleaners and Ideal Cleaners source areas are 8x10'9 or 8 in 1,000,000,000 and 2x10"8 or
2 in 100,000,000 respectively. The cumulative excess cancer risks for groundwater exposures at the Liberty
Services and Ideal Cleaners source areas are 7x10'5 and 9x10'5 respectively.
-------
Noncarcinogenic Risks:
Potential concern for non-carcinogenic effects of a single contaminant in a single medium is expressed as the
hazard quotient (HQ) which is a ratio of the estimated intake derived from the contaminant concentration in a
given medium to the contaminant's reference dose. By adding the HQs for all contaminants within a medium
or across all media to which a given population may reasonably be exposed, the hazard index (HI) can be
generated. The HI provides a useful reference point for gauging the potential significance of multiple
contaminant exposures within a single medium or across various media. A HI value of greater than 1.0 is
generally considered to be of concern with respect to non-carcinogenic effects.
The only source of noncancer health effects for hypothetical future residents is drinking contaminated
groundwater associated with the former One Hour Martinizing source area. The hazard index calculated for
the RME adult is 700 at this location. Liver and kidney damage is the effect of concern associated with
exposure to PCE and TCE. The BRA shows no risk of noncancer effects from exposures at the Liberty
Services and Ideal Cleaners source areas.
Table 6-1
Summary of Risks for RME Future Adult Resident
Groundwater
Soil
One Hour Martinizing
Cancer
(probability)
2x1 0-1
2x1 0-7
Non-cancer
(HI)
700
.001
Liberty Services
Cancer
(probability)
7x1 0-5
8x1 0'9
Non-cancer
(HI)
.3
.00004
Ideal Cleaners
Cancer
(probability)
9x1 0'5
2x1 0-8
Non-cancer
(HI)
.4
.0001
7.
DESCRIPTION OF REMEDIAL ALTERNATIVES
A feasibility study was conducted to develop and evaluate remedial alternatives for the three dry cleaner source
areas at the site. Remedial alternatives were assembled from applicable remedial process options and were
initially evaluated for effectiveness, implementability, and cost. The alternatives meeting these criteria were
further evaluated and compared to the nine criteria required by the NCP. In addition to the remedial
alternatives, the NCP requires that a no-action alternative be considered. The no-action alternative serves
primarily as a point of comparison for the other alternatives.
Several remedial alternatives were evaluated for the two contaminated media present at the site; groundwater
and soil. Remedial alternatives were further categorized by differentiating between the source areas.
Alternatives for the former One Hour Martinizing source area are separated from the alternatives for the Liberty
and Ideal Cleaners source areas due to the high risks posed by the One Hour Martinizing source area
10
-------
relative to the other two source areas. Alternatives for Liberty and Ideal Cleaners source areas are combined
because of the similarity in levels of contamination and associated risks. Presented below are descriptions of
the remedial alternatives that were developed for each source area following initial screening during the
feasibility study. Information on the process options and technologies that were not carried forward for detailed
evaluation following the initial screening can be found in the feasibility study report.
Remedial action objectives consist of media specific goals developed for the protection of human health and
the environment at a site. In the consideration of remedial action objectives, all applicable or relevant and
appropriate requirements (ARARs) must be complied with except where a waiver from a specific requirement
has been granted. The remedial action objectives and remediation goals developed for the contaminated
media at this site are discussed below.
The general remedial action objective for groundwater which provides for the protection of human health
includes the prevention or minimization of ingestion of groundwater having a carcinogenic risk greater than
IxlO"6 and/or a hazard index for non-carcinogens greater than 1.0. The specific remediation goals which would
achieve this objective are the MCLs for the primary contaminants of concern. The remedial action objective
for groundwater which is protective of the environment involves the restoration of groundwater quality to below
MCLs for all contaminants of concern which have MCLs.
The remedial action objective for soil which is protective of human health includes the prevention or
minimization of direct contact with soils having a carcinogenic risk greater than 1x10"*, and/or a hazard index
for non-carcinogens greater than 1.0. The specific remediation goals which would achieve this objective have
not been established. However, EPA's soil screening levels for the contaminants of concern will be used as
a guideline to determine the level of protectiveness achieved by the remedial action. It is important to note that
the soil screening levels published in EPA's Draft Soil Screening Level (SSL) Guidance dated February 16,
1996 are not intended for use as cleanup levels. Rather, the SSLs are intended for use as a guideline to
determine if further remedial action is needed. The remedial action objective for soil which is protective of the
environment includes actions to prevent the migration of contaminants that would result in groundwater
contamination in excess of MCLs. The specific remediation goal which would meet this objective is not known
at this time. Computer models will be used during remedial design to calculate the soil-gas concentrations of
contaminants of concern that could remain in the subsurface soils without causing groundwater contamination
above MCLs due to leaching. In cases where in-situ treatment technologies are employed, the cleanup level
for subsurface soils may be limited by the extent to which the specific technology can achieve mass
contaminant removal. For example, remedies involving soil vapor extraction technologies may be considered
to meet remediation goals after soil-gas levels have stabilized and no significant mass contaminant removal
can reasonably be achieved.
All of the alternatives described below would result in contaminants remaining onsite, which would prompt a
site review to be conducted no less often than every five years as required by CERCLA.
Former One Hour Martinizinq Source Area
Alternative NA-1A: No Action at One Hour Martinizing
Under this alternative, no action would be taken to monitor, control, or remediate the soil or groundwater
contamination. The contaminant plume would be left to naturally attenuate to lower contaminant levels over
time. The only monitoring would be that conducted by the Nebraska Department of Health for municipal
drinking water supplies.
This alternative may eventually achieve remedial action objectives for groundwater, but it is uncertain whether
the processes of natural attenuation would be sufficient to reduce the high contaminant levels to below MCLs.
Therefore the length of time necessary to achieve the remediation goals is not known. Natural attenuation
would not be effective if contaminant sources are not controlled. Contaminants from these sources which
continue leaching to the groundwater could offset the reduction of contaminant levels through natural
11
-------
processes. The ability of this alternative to meet the remedial action objectives for soil is also uncertain. There
are no capital or operating costs associated with this alternative.
Alternative M-1 A: Monitoring and Institutional Controls at One Hour Martinizing
For this alternative, restrictions would be placed on the development of new on-site uses of groundwater and
long-term groundwater monitoring would be implemented to monitor over time the size, shape, and direction
of movement of the contaminant plume. No action would be taken with respect to remediating existing soil or
groundwater contamination. However, operation and maintenance of the containment system installed during
the 1993 removal action would be continued under this alternative. The natural processes of microbial
degradation and dilution would be allowed to attenuate contaminant levels. Existing monitoring wells and city
wells in the area would be monitored as part of this alternative.
This alternative would eventually meet the remedial action objectives for groundwater. However, the length
of time necessary to achieve these objectives is uncertain. The groundwater use restrictions would prevent the
human consumption of groundwater in the area in the short term. However, the effectiveness of these
restrictions to protect human health is dependent upon the city to establish and enforce the necessary
ordinances. Restoration of the aquifer to below MCLs would be dependent upon the effectiveness of natural
degradation processes which is also uncertain. This alternative does not address soil contamination and thus
would not achieve the remedial action objectives for soil for the protection of human health or the environment.
For cost estimating purposes, it is assumed that groundwater monitoring would be conducted for a period of
twenty years. The present worth operation and maintenance (O&M) cost for this alternative is $238,300 with
a capital cost (for engineering) of $24,000. The total present worth cost of alternative M-1 A is $262,300.
SOIL ALTERNATIVES:
Alternative S-1 A: Soil Vapor Extraction with Treatment by Catalytic Incineration at One Hour Martinizing
Alternative S-1 A involves an in-situ (in place) soil remediation process whereby contaminated vapors from the
subsurface soils are extracted and treated by catalytic oxidation or incineration. Under this alternative, a series
of four vapor extraction wells would be positioned along the east side of the One Hour Martinizing facility, the
area shown during the Rl to have the highest levels of soil contamination. Vacuum pressure would be applied
to the extraction wells through the use of a vacuum pump. The extracted vapors would be exhausted to a
catalytic incinerator, where they would be heated to the required operating temperature and then sent through
a catalyst substrate where the contaminants would come in contact with the catalyst material and oxidation
reactions would take place. These reactions would cause the contaminants to chemically break down, thereby
reducing their toxicities. Catalytic incineration is a proven effective treatment for the destruction of the
contaminants present in soils at the site.
Treatability studies conducted by EPA in March 1994 verified the effectiveness of soil vapor extraction
technologies for the Cleburn Street Well site. Vapor extraction pilot tests were conducted at the Ideal Cleaners
source area. These tests demonstrated a high soil-air permeability (on the order of 160 Darcys) rendering soil
vapor extraction very applicable for this site. Based upon this permeability, a vapor extraction rate of
approximately 300 standard cubic feet per minute (SCFM) per extraction well is anticipated to yield a radius of
influence of approximately 40 feet. The vacuum pump would be rated for 1,300 cfm operating at 9 inches of
mercury vacuum pressure. The catalytic incinerator would require approximately 250-300,000 btu/hr of heat
energy which would be supplied by an external source. If implemented, specific equipment specifications would
be confirmed during remedial design.
12
-------
Depending on contaminant concentrations in the stream exiting the incinerator, additional air pollution control
equipment may be required to meet emission standards. The state of Nebraska classifies PCE as a "Toxic Air
Pollutant", and requires all new, modified, and reconstructed sources with the potential to emit 2.5 tons per year
or more or 75 pounds per day of any toxic air pollutant to be permitted and to use "Best Available Control
Technology (BACT). Air monitoring would be conducted to ensure compliance with all applicable emission
standards, controls, and permitting requirements.
Alternative S-1A would effectively meet the remedial action objectives for soil for both human health and the
environment by reducing the contaminant levels in the subsurface soils. The removal of soil contaminants
from this source area would limit the potential for further groundwater contamination by eliminating a continual
point source. In addition, the in-situ removal of soil contaminants would limit the potential for direct contact
exposures. It is assumed that the time necessary to achieve the remedial action objectives for soil would be
five years. The total present worth cost of this alternative is $953,300 consisting of a capital cost of $455,700
and a present worth O&M cost of $497,600.
Alternative S-2A: Soil Vapor Extraction with Treatment by Carbon Adsorption at One Hour Martinizing
This alternative involves the same system for extraction of contaminated vapors from subsurface soils as
provided under alternative S-1 A. Alternative S-2A differs from S-1 A only in the method of treatment of the
extracted vapors.
Under alternative S-2A, the contaminated vapors would flow through three two-stage Granular Activated
Carbon (GAC) adsorbers. Each stage would contain 1,200 pounds of GAG. Sizing of the carbon adsorbers
is based upon the results of treatability studies, and should be verified during remedial design. Carbon
adsorption is a process where activated carbon particles are placed in contact with a vapor or liquid stream
containing organic contaminants. Adsorption occurs when an organic molecule is brought in contact with the
microcrystalline pore structure of the activated carbon surface and held there by physical and/or chemical
forces. The carbon must be regenerated or replaced after organic molecules build up on the carbon surface.
Carbon adsorption is a proven effective treatment for PCE, but involves the physical transfer of contaminants
and is not a destruction technology. Similar to alternative S-1 A, air monitoring would be conducted to ensure
compliance with applicable air regulations.
Alternative S-2A would effectively achieve the remedial action objectives for soil for both the protection of
human health and the environment by reducing contaminant levels in the subsurface soils. The removal of
soil contaminants from this source area would limit the potential for further groundwater contamination by
eliminating a continual point source. In addition, the in-situ removal of soil contaminants would limit the potential
for direct contact exposures. It is assumed that the time necessary to achieve the remedial action objectives
for soil would be five years. The total present worth cost of this alternative is $541,300 consisting of a capital
cost of $271,100 and a present worth O&M cost of $270,200.
GROUNDWATER ALTERNATIVES:
Each of the groundwater alternatives presented below includes the continued operation of the existing extraction
well, groundwater use restrictions, and long-tarm monitoring.
Alternative G-1: Groundwater Extraction and Treatment by Air Stripping
Under this alternative, a series of groundwater extraction wells would be installed in the vicinity of the former
One Hour Martinizing facility. Contaminated groundwater would be pumped from the wells and discharged to
an air stripping tower where contaminants would be removed from the water stream. Treated water would be
discharged to either the storm sewer or sanitary sewer depending on the contaminant concentrations.
The groundwater extraction system would be designed to capture the most highly contaminated groundwater
and would prevent further migration of the contaminant plume. Pump tests and modeling conducted during
13
-------
the treatability study indicated that three groundwater extraction wells pumping at a rate of 40 gallons per
minute per well should exert sufficient hydraulic control to capture dissolved phase contaminants migrating from
the source area.
Air stripping technology consists of the controlled contact of a liquid stream containing volatile contaminants
with a clean air stream. This contact promotes the transfer of the volatile components from the liquid to the
vapor phase. This phenomenon is known as mass transfer. The degree of mass transfer that can occur
depends upon an individual compound's ability to partition into the vapor phase, which is reflected by its Henry's
Law constant. Air stripping has been proven effective for all of the VOCs identified at this site.
Modeling efforts conducted during the treatability study revealed that the air stripper should consist of a three
foot diameter tower with a twenty-five foot section of the tower containing random packing, and should be
equipped with a three horsepower blower capable of achieving a 1,600 cubic feet per minute (CFM) flow rate.
Similar to the soil vapor extraction alternatives discussed above, operation of an air stripper would result in an
exiting air stream containing PCE which is classified by the state of Nebraska as a "toxic air pollutant". Using
a worst case scenario (the maximum detected values of PCE in groundwater), the Nebraska Department of
Environmental Quality (NDEQ) performed calculations of the potential to emit. The calculations show that a
permit and additional treatment of the exiting air stream may be necessary. Proper permitting requirements
would be met and air monitoring would be conducted to verify compliance with the state air regulations.
It is estimated that a period of twenty years would be necessary for alternative G-1 to achieve the remediation
goals of MCLs in the shallow groundwater. It is important to note that the high concentrations of PCE found
around this source area exceed the solubility of PGE in water, which could be indicative of the presence of
dense non-aqueous phase liquid (DNAPL). No DNAPL was found during the Rl, but an exhaustive effort was
not conducted to locate DNAPL zones. If DNAPL is present, the likelihood of achieving MCLs in areas where
the DNAPL is located is very low. In the event that DNAPL zones are located or other site conditions are
present which prevent attainment of cleanup levels in a reasonable timeframe , a waiver would be obtained to
waive MCLs as ARARs for portions of the plume. MCLs would remain ARARs for areas of the plume containing
dissolved phase VOCs. Additional groundwater monitoring may be conducted during remedial design and
performance monitoring of the extraction/treatment system will be implemented following start-up of the
remediation system. Information resulting from these efforts will be used to evaluate the need for an ARAR
waiver.
Alternative G-1 would effectively achieve the remedial action objectives for groundwater for both protection of
human health and the environment through the removal and treatment of contaminated groundwater. In
addition, short-term protection of human health is provided by the groundwater use restrictions which are
intended to prevent human exposure to the groundwater.
The estimated present worth cost of this alternative is $387,950 including a capital cost of $173,450 and present
worth O&M cost of $214,500. The present worth cost of this alternative including air treatment for twenty years
is $615,400, of which $230,200 is capital cost and $385,200 is present worth O&M cost.
Alternative G-2: Groundwater Extraction and Treatment by Carbon Adsorption
This alternative is similar to Alternative G-1, in that the same extraction well system would be used to collect
contaminated groundwater. However, a different treatment process would be employed. The treatment
process for this alternative would be liquid phase carbon adsorption. Treated groundwater would then be
discharged to the storm water sewer or sanitary sewer depending on the residual contaminant concentrations.
The liquid phase carbon adsorption treatment process is similar to that described under alternative S-2A for
vapor phase treatment. The liquid phase process involves granular activated carbon particles placed in contact
with a wastewater stream containing dissolved phase organic contaminants. Adsorption occurs when an
organic molecule is brought in contact with the microcrystalline pore structure of the activated carbon surface
14
-------
and held there by physical and/or chemical forces. Results of the bench scale carbon adsorption studies
conducted as part of the Treatability Study (Sverdrup 1994), indicated that carbon adsorption is a viable
treatment process for the removal of the VOCs present.
The treatability study further concluded that the carbon treatment system should consist of two 10,000 Ib carbon
adsorbers operated in series at an average flow rate of 120 gallons per minute. Based on these design
parameters, the carbon would need to be replaced every four months. However, as contaminant
concentrations in the groundwater decrease over time, the frequency of carbon replacement would also
decrease. For cost estimation purposes, it is assumed that carbon replacement would take place every four
months for the first ten years of operation and every six months for the remaining ten years of operation.
Alternative G-2 would effectively meet the remedial action objectives for groundwater for both the protection
of human health and the environment by removing and treating contaminated groundwater. It is estimated that
this alternative is capable of achieving the remediation goals of MCLs within twenty years. In addition, short-
term protection of human health is provided by the groundwater use restrictions. The discussion under
alternative G-1 regarding the potential inability to achieve ARARs in areas found to contain DNAPL also applies
to alternative G-2.
The present worth cost of this alternative is estimated at $940,450 including a capital cost of $272,550 and a
present worth O&M cost of $667,900. The elevated cost as compared to other groundwater treatment options
is due to the cost of carbon replacement or regeneration.
Alternative G-3: Groundwater Extraction with Discharge to Sanitary Sewer
Alternative G-3 involves an identical groundwater extraction system as alternatives G-1 and G-2, but no on-site
treatment process would be utilized. Groundwater produced by the extraction wells would be discharged
directly to the city sanitary sewer for treatment in the Publicly Owned Treatment Works (POTW).
EPA is presently operating an extraction well located on the down gradient side of the former One Hour
Martinizing facility with all water produced discharging to the POTW via the sanitary sewer as part of an interim
removal action. The objective of the removal action was to contain the contaminant plume until a permanent
remedy could be selected. Alternative G-3 would be an extension of this system, and would have the purpose
of achieving the previously identified remedial action objectives.
Results of the treatability study indicated that the introduction of PCE into the waste water treatment facility is
not affecting the efficiency or operation of the treatment plant. However, the existing sewer system can only
handle a limited amount of additional flow which could be further restricted in the future. Potential risks
associated with this alternative include the exposure of city workers to uncontrolled emissions of VOCs which
could be volatilized in the sewer lines.
Alternative G-3 would meet the remedial action objectives for groundwater for the protection of human health
and the environment, but would not involve a treatment component and would not offer as high a degree of
protectiveness or permanence as alternatives G-1 and G-2. Uncertainties associated with this alternative such
as the flow limitations of the sewers, as well as the structural condition of the sewer lines, would render it less
protective than the other groundwater treatment options. Groundwater use restrictions would provide
protection of area residents in the short term. Assuming an extraction rate of 120 gallons per minute, the
estimated time required to achieve MCLs in the shallow groundwater is twenty years. Again, the discussion
under alternative G-1 regarding DNAPLs also applies to alternative G-3.
The present worth cost estimate for alternative G-3 is $245,400, of which $103,400 is the capital cost and
$142,000 is the present worth O&M cost.
15
-------
Liberty Cleaners and Ideal Cleaners Source Areas
Alternative NA-1B: No Action at Liberty/Ideal Cleaners
Under this alternative, no action would be taken to monitor, control, or remediate the soil or groundwater
contamination. The contaminant plumes would be left to naturally attenuate to lower contaminant levels over
time. The only monitoring would be that conducted by the state for municipal drinking water supplies.
Since the excess cancer and noncancer risks posed by these source areas do not exceed the level at which
EPA generally requires remedial action, alternative NA-1B could be considered protective of human health and
the environment. Existing conditions at these source areas already meet the remedial action objectives for soil.
However, PCE levels in the shallow groundwater remain above MCLs and therefore do not meet the remedial
action objectives for groundwater. The processes of natural attenuation may be sufficient to reduce the
contaminant levels in the shallow groundwater to below MCLs, but the period of time required to achieve the
remediation goals is unknown. If contaminant sources are not controlled, contaminants which continue to leach
contaminants to the groundwater could offset the positive effects of natural attenuation processes. There is
no cost associated with this alternative.
Alternative M-1B: Monitoring and Institutional Controls at Liberty/Ideal Cleaners
This alternative would involve groundwater use restrictions in the vicinity of the source areas and long-term
groundwater monitoring. Restrictions would be designed to prevent the use of the shallow groundwater for
drinking water and other household uses, and would call for the registration of any new wells in the area. The
city of Grand Island would be responsible for passing and enforcing the necessary city ordinances.
Groundwater monitoring would include the installation of one new monitoring well placed downgradient of each
source area and routine sampling of these wells and existing wells at each of the source areas to track the
movement of the contaminant plumes. The natural processes of microbial degradation and dilution would be
allowed to attenuate contaminant levels.
Given existing conditions at each of the source areas, this alternative would meet the remedial action objectives
for soil. EPA believes this alternative would also meet the remedial action objectives for groundwater, but the
period of time required to achieve MCLs is uncertain. Given the low PCE levels found in the shallow
groundwater, it is believed that natural attenuation processes would reduce contaminant levels to below MCLs
within ten years. Groundwater monitoring would be conducted to monitor the effectiveness of natural
attenuation. Groundwater use restrictions would provide for the protection of human health for both the short
and long terms and would therefore meet the remedial action objective for groundwater for the protection of
human health.
For cost estimating purposes, the monitoring program is assumed to consist of quarterly monitoring for the first
two years and semi-annual monitoring for the remaining eight years. The capital cost associated with this
alternative $33,400 and the present worth O&M cost is $129,400 for a total present worth cost of $162,800 for
both source areas.
Alternative M-2B: Monitoring and Institutional Controls with a Contingency for Soil Vapor Extraction
and treatment by Carbon Adsorption
This alternative includes the same long-term groundwater monitoring program and use restrictions as described
under alternative M-1B above, with a contingency for implementing a soil treatment alternative, S-2B, described
below. The contingency would be implemented if monitoring results show that natural attenuation is not
effectively reducing the contaminant levels in the groundwater. By implementing alternative S-2B, the
contaminants in the subsurface soils would be removed and treated, thus removing a continual point source
of groundwater contamination. Removing the source of contamination should allow natural attenuation
processes to reduce groundwater contaminant levels more efficiently.
16
-------
It is expected that alternative M-2B would meet the remedial action objectives for both groundwater and soil
within ten years. However, there is some uncertainty regarding the period of time necessary for natural
attenuation to achieve the remediation goals.
The total present worth cost of this alternative is $420,800 assuming that the contingency action is implemented
at both source areas. This cost includes a capital cost of $169,800 and a present worth O&M cost of $251,000.
SOIL ALTERNATIVES:
Alternative S-1B: Soil Vapor Extraction and Treatment by Catalytic Incineration at Liberty/Ideal Cleaners
Alternative S-1B is nearly identical to alternative S-1A for the former One Hour Martinizing source area. The
processes would be identical with respect to extraction and treatment of contaminated vapor. The differences
relate to the smaller scale of the system and the shorter length of time required to remediate the lower levels
of contamination at Liberty and Ideal Cleaners source areas.
Based on results of the treatability study, it is anticipated that two vapor extraction wells producing a vapor flow
rate of 200 CFM each would effectively capture the contaminated soil vapors. The required vacuum pump
would be rated for a capacity of 400 CFM operating at a pressure of 6 inches of mercury and driven by a 7.5
horsepower motor. Heat energy requirements for the catalytic incinerator are approximately 85,000 btu/hr
which would need to be provided by an external energy source.
Due to the low concentrations of PCE detected in the subsurface soils at these two source areas, it is not
believed that emissions from the incinerator would trigger any permitting or treatment requirements under the
Nebraska air regulations. However, air monitoring would be conducted to ensure compliance.
Alternative S-1B would effectively meet the remedial action objectives for soil for both human health and the
environment by reducing the contaminant levels in the subsurface soils. The removal of soil contaminants
from these source areas would limit the potential for further groundwater contamination by eliminating a
continual point source. In addition, the in-situ removal of soil contaminants would limit the potential for direct
contact exposures. It is assumed that the time necessary to achieve the remedial action objectives for soil
would be two years. The total present worth cost of this alternative per source area is $344,950 (or $689,900
for both source areas) consisting of a capital cost of $159,350 and a present worth O&M cost of $185,600.
Alternative S-2B: Soil Vapor Extraction and Treatment by Carbon Adsorption at Liberty/Ideal
Cleaners
Alternative S-2B is nearly identical to alternative S-2A for the former One Hour Martinizing source area. The
processes would be identical with respect to extraction and treatment of contaminated vapor. The differences
relate to the smaller scale of the system and the shorter length of time required to remediate the lower levels
of contamination at Liberty and Ideal Cleaners source areas.
The vapor extraction system would be the same as that described for alternative S-1B above. The carbon
adsorption system would consist of two stages, each containing 1,200 Ibs of carbon. If this alternative is
implemented, equipment specifications would be confirmed during remedial design. As in any carbon
adsorption system, the carbon would need to be replaced or regenerated periodically as organics build up on
the surface of the carbon. Air monitoring would be conducted to ensure compliance with Nebraska air
regulations.
Alternative S-2B would effectively meet the remedial action objectives for soil for both human health and the
environment by reducing the contaminant levels in the subsurface soils. The removal of soil contaminants
from these source areas would limit the potential for further groundwater contamination by eliminating a
continual point Source. In addition, the in-situ removal of soil contaminants would limit the potential for direct
contact exposures. It is assumed that the time necessary to achieve the remedial action objectives for soil
17
-------
would be two years. The total present worth cost of this alternative per source area is $129,000 (or $258,000
for both source areas) consisting of a capital cost of $68,200 and a present worth O&M cost of $60,800.
GROUNDWATER ALTERNATIVES:
Alternative G-4: Groundwater Extraction and Discharge to Sanitary Sewer at Liberty/Ideal Cleaners
Under this alternative, contaminated groundwater at both source areas would be extracted and discharged to
the sanitary sewer for treatment at the POTW. Extraction systems at each source area would consist of one
extraction well, pump, and piping necessary for connection to an existing sanitary sewer line. It is estimated that
an extraction rate of 40 gpm would be sufficient to capture the contaminant plumes emanating from these
source areas. Groundwater use restrictions and monitoring would also be conducted under this alternative.
Alternative G-4 would achieve the remedial action objectives for groundwater for both the protection of human
health and the environment. It is estimated that the remediation goals of MCLs would be reached in the shallow
groundwater within ten years of operation. Groundwater use restrictions would provide for protection of human
health for both the short and long-terms by preventing groundwater exposures. Some risk to city workers may
be presented by the volatilization of VOCs in the sewer lines, but this is expected to be minimal given the low
contaminant concentrations found at these source areas. Additional uncertainty exists regarding the capacity
of the city sewer system.
Assuming a ten year period of operation, the present worth cost of this alternative is estimated at $67,800 per
source area which includes $31,500 for capital costs and $36,300 for O&M costs.
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The remedial alternatives developed in the FS were analyzed in detail for the One Hour Martinizing source area
and for the Liberty and Ideal Cleaners source areas. The alternatives were then evaluated with respect to the
nine criteria specified in the NCP. For reference, these criteria include:
1. Overall protection of human health and the environment;
2. Compliance with applicable or relevant and appropriate requirements;
3. Reduction of toxicity, mobility, and volume through treatment;
4. Long-term effectiveness and permanence;
5. Short-term effectiveness;
6. Implementability;
7. Cost;
8. State acceptance; and
9. Community acceptance.
A discussion of how the above-described alternatives compare to each of these criteria is provided below for
the One Hour Martinizing source area and then the Liberty and Ideal Cleaners source areas. The comparative
analysis is summarized on Tables 8-1 and 8-2.
Former One Hour Martinizing Source Area:
Criterion 1: Protection of Human Health and the Environment
This criterion addresses whether a remedy provides adequate protection and describes how risks posed
through each exposure pathway are eliminated, reduced, or controlled through treatment, engineering controls,
or institutional controls.
18
-------
Alternatives S-1 A, S-2A, G-1, and G-2 provide a high degree of protectiveness by removing and treating both
subsurface soil contamination and groundwater contamination. Under alternatives S-1 A and S-2A, the removal
of soil contaminants from this source area would eliminate the risks due to soil exposures through treatment
and would limit the potential for further groundwater contamination by eliminating a continual point source.
Alternatives G-1 and G-2 also provide for the elimination of risks due to groundwater exposures through
treatment. Alternative G-3 provides a moderate degree of protectiveness in that the groundwater is removed,
thus eliminating exposures, but the alternative does not offer a treatment component. All three groundwater
alternatives also offer protectiveness of human health by eliminating groundwater exposures through
institutional controls (groundwater use restrictions). The protectiveness offered by alternative M-1A is
considered to be low because the alternative does not address subsurface soil contamination and does not
offer a treatment component for groundwater which is extracted from the existing extraction well. Under
alternative M-1 A, some protectiveness of human health is provided through institutional controls which would
prevent groundwater exposures, but risks due to subsurface soil exposures would remain and contaminated
subsurface soils would continue to act as a source of groundwater contamination. Alternative NA-1A is not
protective of human health or the environment because it does not address risks due to subsurface soil or
groundwater contamination.
Criterion 2: Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
Applicable requirements are those cleanup standards, standards of control, and other substantive
requirements, criteria, or limitations promulgated under Federal or State environmental or facility siting laws
that specifically addresses a hazardous substance, pollutant, contaminant, remedial action, location, or other
circumstance at a CERCLA site. Relevant and appropriate requirements are those cleanup standards,
standards of control, and other substantive requirements, criteria, or limitations promulgated under Federal or
State environmental siting laws that, while not "applicable" to a hazardous substance, pollutant, contaminant,
remedial action, location, or other circumstance at a CERCLA site, address problems or situations sufficiently
similar to those encountered at the CERCLA site that their use is well suited to the particular site. Compliance
with ARARs addresses whether a remedy will meet all Federal and State environmental laws and/or provide
basis for a waiver from any of these laws. A comprehensive list of ARARs was provided in the proposed plan
for the site, and a discussion of the ARARs is provided below.
Alternatives S-1 A, S-2A, G-1, G-2, and G-3 would comply with the associated ARARs. Specifically, the soil
vapor extraction alternatives S-1 A and S-2A would comply with the Nebraska air regulations. The three
groundwater alternatives would comply with MCLs promulgated under the Safe Drinking Water Act for the
contaminants of concern in areas not containing DNAPL, and would also comply with any pretreatment
standards and permitting requirements under the National Pollutant Discharge Elimination System (NPDES)
Program for the regulation of discharges to the city sanitary sewer or storm sewer. Air emissions under
alternative G-1 would be subject to and comply with the Nebraska air regulations.
Any areas found to contain DNAPL will not comply with ARARs because it is very doubtful that MCLs can be
achieved in DNAPL zones. If such DNAPL zones are located, a technical impracticability waiver under
CERCLA will be sought to waive MCLs as ARARs for these areas.
Alternative M-1 A is not expected to comply with ARARs because it is doubtful that MCLs could be achieved at
this source area without aggressive groundwater extraction and treatment due to the very high contaminant
levels in the shallow groundwater. The no-action alternative, NA-1 A, would also not comply with ARARs as
MCLs are not likely to be achieved solely by the processes of natural attenuation.
Criterion 3: Long-Term Effectiveness and Permanence
This criterion evaluates the ability of a remedy to maintain reliable protection of human health and the
environment over time. The criterion includes the consideration of residual risk and the adequacy and reliability
of controls.
19
-------
Alternatives S-1A, S-2A, G-1, G-2, and G-3 all provide a high degree of effectiveness by removing contaminants
from the subsurface soils and groundwater thus minimizing residual risks at the site. Alternative S-1A offers
a higher degree of permanence than alternative S-2A because incineration is a destruction technology as
opposed to carbon adsorption which is a transfer technology. Both soil treatment options are equally effective,
but incineration is more permanent. Of the groundwater alternatives, G-1 and G-2 offer a higher degree of
permanence than G-3 because alternative G-3 does not include a treatment component. Some residual risk
is also associated with alternative G-3 in that city workers could be exposed to contaminants which may
volatilize in the sewer lines.
Alternative M-1A does not provide for the removal or treatment of contaminated groundwater and does not
address contaminated subsurface soils at all, and therefore does not provide for long-term effectiveness or
permanence. Substantial residual risks are associated with alternative M-1 A in that contaminants would remain
in the subsurface soils which would continue to act as a source of groundwater contamination, and
contaminants would remain in the groundwater as well. Alternative M-1 A does provide for controls to prevent
exposures to contaminated groundwater, but the reliability of these controls is dependent upon the city passing
and enforcing the necessary ordinances.
The no-action alternative, NA-1A, does not provide for long-term effectiveness or permanence because no
action would be taken to address contaminated subsurface soils or groundwater. Significant residual risks
would remain at the site, and no controls would be implemented to prevent or minimize exposures.
Criterion 4: Reduction of Toxicitv. Mobility, or Volume Through Treatment
This criterion evaluates the preference for a remedy that employs treatment technologies that reduce health
hazards, contaminant migration, or the quantity of contaminants at a site.
The two soil alternatives, S-1A and S-2A, and the three groundwater alternatives, G-1, G-2, and G-3, all provide
for the reduction of contaminant mobility and volume by physically removing contaminants from the site through
soil vapor extraction and groundwater extraction. While all of the alternatives reduce health hazards by
removing the contaminants and eliminating exposures, only one alternative, S-1A, actually serves to reduce
the toxicity of the contaminants through incineration, which is a proven effective destruction technology. The
treatment technologies employed by alternatives S-2A, G-1 and G-2 are also proven effective treatment
technologies for the contaminants of concern, but are transfer technologies and do not directly alter the toxicity
of the contaminant compounds. However, under alternatives S-2A and G-2, the contaminants would ultimately
be destroyed at an offsite carbon regeneration facility.
Alternative M-1 A provides for some reduction of mobility and volume through the continued operation of the
existing extraction well. However, the operation of one well under alternative M-1 A would not provide as great
a reduction in mobility and volume as trie three groundwater alternatives which would employ three extraction
wells to exert hydraulic control over a larger area. Alternative M-1 A involves groundwater use restrictions which
would lessen the likelihood of human health threats, but does not contain a treatment component and would
therefore not provide for the reduction of contaminant toxicity.
Alternative NA-1A does not provide for any reduction of toxicity, mobility, or volume.
Criterion 5: Short-Term Effectiveness
Short-term effectiveness refers to the period of time needed to complete the remedy and any adverse impacts
on human health and the environment that may be posed during the construction and implementation of the
remedy.
The two soil alternatives, S-1 A and S-1 B, are considered to offer a high degree of short-term effectiveness in
that these technologies would allow for contaminant levels in the subsurface soils to be reduced very quickly
20
-------
upon start-up. It is expected that both of these alternatives are capable of meeting the remedial action
objectives within five years of start-up, with the majority of contaminant reduction occurring in the first two years.
Due to the high soil-air permeability confirmed during the treatability study, the soil vapor extraction alternatives
could achieve remediation goals even more quickly than expected. Because soil vapor extraction technologies
treat soils in place, there would be little risk to onsite workers and area residents during construction and
implementation of alternatives S-1A and S-2A. However, risks to onsite workers could occur due to exposure
to contaminated subsurface soils during installation of the vapor extraction wells. There may be some risk
associated with air emissions during implementation of these alternatives, but these risks would be minimized
through compliance with the Nebraska air regulations.
The three groundwater alternatives, G-1, G-2, and G-3 offer an equal degree of short-term effectiveness. The
time anticipated to meet remediation goals is twenty years for each groundwater alternative. Onsite workers
could be exposed to contaminated subsurface soils during installation of the extraction wells. Alternative G-2
would involve minimal risk to site workers during periodic replacement of the spent carbon. Alternative G-1
would carry some risk to area residents due to emissions from the air stripper, but these risks would be
minimized by compliance with the Nebraska air regulations. City workers could be exposed to contaminated
vapors which may volatilize in the sewer lines under alternative G-3.
Alternative M-1A would not provide short-term effectiveness. Because the alternative does not involve removal
and treatment of contaminated subsurface soils or groundwater, contaminants would be left in the ground to
degrade naturally over time. It is uncertain whether the processes of natural attenuation could achieve
remediation goals given the high contaminant concentrations found at this source area. There would be no risk
to onsite workers or area residents during implementation as no physical construction activities are called for
under this alternative.
Alternative NA-1Adoes not provide short-term effectiveness, and does not present any risks to onsite workers
or area residents as no action would be taken.
Criterion 6: Implementabilitv
This criterion evaluates the technical and administrative feasibility of a remedy, including the availability of
materials and services needed to implement the remedy. It also includes coordination of Federal, State, and
local governments which may be necessary to implement a remedy.
The materials and services needed to implement all of the alternatives are readily available. Associated
equipment is expected to be located on a portion of the former One Hour Martinizing property. Alternative S-2A
offers an advantage in this area due the availability of an existing system built and used by EPA at another
CERCLA site in Nebraska. The existing unit has adequate capacity and would require minimal retrofitting to
be fully operational at this source area. Alternative G-3 is slightly less implementable than the other alternatives
because of the potential capacity limitations of the existing sewer lines and the close coordination between the
city and EPA that would be required to construct and operate the remedy.
Criterion 7: Cost
This criterion examines the estimated costs for each remedial alternative. For comparison, capital and annual
O&M costs are used to calculate a present worth cost for each alternative.
The lowest cost alternatives are NA-1A and M-1A. There are no costs associated with alternative NA-1A and
the estimated present worth cost of alternative M-1A is $262,300.
Of the soil alternatives, the least costly is alternative S-2A having a present worth cost of $541,300. This cost
does not reflect the use of an existing treatment system, so if the existing system is used, the cost associated
with alternative S-2A would be significantly lower. The estimated present worth cost of alternative S-1A is
$953,600. The high cost of alternative S-1A is due to the fuel costs needed to operate the catalytic incinerator.
21
-------
Of the groundwater alternatives, G-3 is the least costly with an estimated present worth cost of $245,400. The
present worth cost of alternative G-1 is $387,950 without air treatment and $615,400 with air treatment. The
estimate for air treatment is conservatively high because it assumes that air treatment would be required for
the duration of the remedy (twenty years). If air treatment is required, it is likely that it would only be necessary
during the early years of operation of the remedy because the majority of contaminant reduction should occur
during the first few years, and remaining contaminant concentrations would not continue to trigger the need for
treatment under the Nebraska air regulations. The present worth cost of alternative G-2 is $940,450, which is
significantly higher than alternative G-1 due to higher operating costs associated with periodic carbon
replacement.
Criterion 8: State Acceptance
This criterion assesses the position of the state regulatory agency regarding the remedial alternatives preferred
by EPA. The NDEQ has been involved throughout the history of the site and participated in a public hearing
in support of EPA's preferred alternatives. In addition, the NDEQ provided a letter to EPA indicating its
agreement with the preferred alternatives for this site.
Criterion 9: Community Acceptance
This criterion considers the level of community support for EPA's preferred alternatives by reviewing public
comments received during the public comment period or at the public hearing. Approximately 12 members
of the community attended the public hearing held on February 27,1996. In general, there was public support
for EPA's preferred alternatives for remediating the contamination at the site. However, some public concern
was voiced with regard to redevelopment of an abandoned property at the site. EPA is working with the city and
state to assist in redevelopment efforts. A representative from the city water utility expressed concern that
continued plume migration could impact the Pine Street municipal well, and indicated that the city remains
dependent on this well during periods of peak water demand. No written comments were received from the
public during the public comment period which ran from February 15,1996 through March 16,1996.
Liberty and Ideal Cleaners Source Areas:
Definitions of each of the criteria are provided above and are not repeated in the discussion for Liberty and Ideal
Cleaners source areas.
Criterion 1: Protection of Human Health and the Environment
Alternative M-2B offers the highest degree of protectiveness because it provides for the elimination of human
exposure to the contaminated groundwater through institutional controls, and includes a contingency for the
removal of contaminants from subsurface soils through treatment. Due to the low levels of contaminants found
at these source areas, EPA believes that the processes of natural attenuation would achieve remediation goals.
Alternatives M-1B and the two soil treatment alternatives, S-1B and S-2B, also offer a significant degree of
protectiveness on an individual basis, but when combined, the level of protectiveness is increased. The
protectiveness of alternative NA-1B is considered moderate because natural attenuation could achieve
remediation goals over time, but no controls are included to prevent exposures to groundwater in the short-
term. Alternative G-4 also provides a moderate level of protectiveness by removing contaminated groundwater
from the subsurface, but does not include a treatment component.
Criterion 2: Compliance with Applicable or Relevant and Appropriate Requirements
All of the alternatives would comply with ARARs in that MCLs would eventually be achieved by the processes
of natural attenuation.
22
-------
Criterion 3: Long-Term Effectiveness and Permanence
All of the alternatives, except the no-action alternative, offer a high degree of long-term effectiveness and
permanence in that residual risks are expected to be minimal given the already low contaminant concentrations
at the source areas. Alternative M-2B offers an additional measure of long-term effectiveness and permanence
by providing a contingency for the removal of contaminants from the subsurface soils to remove a continual
point source of groundwater contamination.
Criterion 4: Reduction of Toxicitv. Mobility, and Volume
The only alternatives which address this criterion are alternatives S-1B, S-2B, and G-4. Each of these
alternatives reduces the mobility and volume of contaminants by either the removal of contaminants from
subsurface soils or the groundwater. Alternative M-2B could also reduce the mobility and volume of
contaminants if the soil treatment contingency Were to be employed. The no-action alternative, NA-1 A, and
alternative M-1B do not provide for the reduction of toxicity, mobility, or volume of contaminants as no actions
would be taken to remove contaminants from the environment. None of the alternatives provides for the
reduction of contaminant toxicity.
Criterion 5: Short-Term Effectiveness
Alternatives S-1 B and S-2B provide the highest degree of short-term effectiveness in that they would remove
subsurface contaminants within an expected two years. Neither of the soil treatment alternatives would have
an adverse impact on human health or the environment during construction or implementation. Given the low
concentrations of contaminants at these source areas, it is unlikely that air emissions resulting from the soil
treatment alternatives would impact human health or the environment, and all applicable air regulations would
be complied with. Alternative G-4 would achieve remediation goals within an expected ten years and is
considered to be moderately effective in the short-term. Risk during implementation of this alternative could
include exposures of city workers to contaminated vapors being volatilized in the sewer lines. Alternatives M-1B
and M-2B are considered to provide a moderate degree of short-term effectiveness because, while the time
required for natural attenuation to meet remediation goals is uncertain, the alternatives provide for groundwater
use restrictions to prevent groundwater exposures in the short-term. Both of these alternatives call for
monitoring over a ten year period. The no-action alternative does not provide for short-term effectiveness.
Criterion 6: Implementabilitv
All of the alternatives, except G-4, are considered highly implementable because all of the materials and
services needed to construct and implement the alternatives are readily available. Alternative G-4 is slightly
less implementable than the other alternatives because of the potential capacity limitations of the existing sewer
lines and the close coordination between the city and EPA that would be required to construct and operate the
remedy.
Criterion 7: Cost
There are no costs associated with the no-action alternative. The least costly alternative is G-4 with a present
worth cost of $67,800 for both source areas. The present worth cost of alternative M-1B is $162,800 for both
source areas. The two soil treatment alternatives, S-1B and S-2B, have estimated present worth costs of
$689,900 and $258,000 respectively per source area. The higher cost of alternative S-1B is due to the fuel
costs that would be needed to operate the incinerator. Alternative M-2B has an estimated present worth cost
of $420,800 (or $210,400 per source area) which reflects the addition of the costs of alternative M-1B and
alternative S-2B.
23
-------
Criterion 8: State Acceptance
The discussion provided under this criterion for the One Hour Martinizing source area also applies to the Liberty
and Ideal Cleaners source areas.
Criterion 9: Community Acceptance
The discussion provided under this criterion for the One Hour Martinizing source area also applies to the Liberty
and Ideal Cleaners source areas.
24
-------
-------
Comparison of Alternatives for One Hour Martinizina Source Area
ALTERNATIVE
NA-1A:No Action
M-1 A:Monltorlng/
Institutional Controls
S-1 A: Soil Vapor
Extraction/Catalytic
Incineration
S-2AJ Soil Vapor '
extraction/ Carbon
Adsorption
<3-t: <«i*oimi*W4itef
Extraction/Air stripping
G-2: Groundwater
Extraction/ Carbon
Adsorption
G-3: Groundwater
Extraction/Discharge to
Sanitary Sewer
Protection of
Health and
Environment
Low
Low
High
High
High
High
Moderate
Compliance
with ARAR*
Low
Low
High
High
High
High
High
Long-term
, Effectiveness
Low
i Low
High
High
High
High
High
Reduction
of Toxlclty.
Mobility and
Volume
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate
Short-term
Effectiveness
Low
Low
High
High
Moderate
Moderate
Moderate
implenieiil-
ablllty
High
High
High
High
High
High
Moderate
Cost ($)
0
262,300
953,600
541,300
387,950
(note 1)
940,450
245,400
1. Cost does not include air treatment; cost including air treatment would be $615,400.
2. Shaded rows indicate preferred alternatives.
25
-------
TABLE 8-2
Comparison of Alternatives for Liberty/Ideal Cleaners Source Areas
ALTERNATIVE
N A- IB: No Action
M- 1 B: Monitoring/
Institutional
Controls
S-1B: Soil Vapor
Extraction/
Catalytic
Incineration
S-2B: Soil Vapor
Extraction/Carbon
Adsorption
M«2B:
monttorlng/lnatnutlanal
Control* wHh
contin0«nt«y tor son
Tratrtmanl by C««rbon
Attnoi-frtion
G-4: Groundwater
Extraction/
Discharge to
Sanitary Sewer
Protection of
Health and
Environment
Moderate
Moderate
High
High
High
Moderate
Compliance
with ARARs
High
High
High
High
High
High
Long-term
Effectiveness
Moderate
High
High
High
High
High
Reduction of
Toxlclty,
Mobility, and
Volume
Low
Low
Moderate
Moderate
Low to
Moderate
Moderate
Short-term
Effectiveness
Low
Moderate
High
High
Moderate
Moderate
Implement-
ability
High
High
High
High
High
Moderate
Cost ($)
0
162,800
344,950
129,000
291,800
67,800
NOTES:
1. Shaded row indicates preferred alternative.
26
-------
9. SELECTED REMEDY
EPA has selected a remedy for the One Hour Martinizing source area and a separate remedy for the Liberty
and Ideal Cleaners source areas. Due to the differences in contaminant levels and associated risks between
the One Hour Martinizing source area and the Liberty and Ideal Cleaners source areas, the selected remedies
are discussed separately below.
One Hour Martinizing Source Area:
The remedy selected for this source area is a combination of alternatives S-2A and G-1. The components of
this selected remedy include:
•• Monitoring of groundwater, discharged treated water, and air emissions;
•• Institutional controls to restrict groundwater use;
•• Extraction of subsurface contaminants using soil vapor extraction;
•• Treatment of extracted soil vapors by carbon adsorption;
•• Extraction of groundwater containing contaminants above MCLs; and
•• Treatment of extracted groundwater by onsite air stripping.
The groundwater extraction well installed during the 1993 removal action will continue to operate under this
remedy and will eventually become part of the groundwater extraction and treatment system. Groundwater
monitoring conducted under the removal action will also continue.
Institutional controls and groundwater monitoring were not presented as part of the preferred remedy for
groundwater at this source area in the proposed plan. However, they were included in the discussion and
evaluation of Alternative G-1 in the feasibility study and were also presented as a separate alternative in the
proposed plan.
The institutional controls will involve restrictions on the installation of new groundwater wells for private use in
the area of contamination and long-term groundwater monitoring. Restrictions will be designed to prevent the
use of shallow groundwater for drinking water and other household uses, and will call for the registration of new
wells in the area of contamination. The city of Grand Island will be responsible for passing and enforcing the
necessary ordinances. Groundwater monitoring will include the installation of one new monitoring well placed
downgradient of each source area and routine sampling of these wells and existing wells to track the movement
of the contaminant plumes. The natural processes of microbial degradation and dilution will be allowed to
attenuate contaminant levels.
A phased approach to remediation of this source area will be employed. The first phase involving groundwater
containment is already in place. The next phase consists of source control/removal and involves the design
and implementation of alternative S-2Afof the extraction and treatment of subsurface soil contamination. This
phase will also include implementation of the institutional controls which will restrict the installation of new
groundwater wells in the area of the plume. The third and final phase for groundwater restoration involves
the design and implementation of alternative G-1, groundwater extraction and treatment by air stripping, and
long-term groundwater monitoring to evaluate the performance of the remediation system.
Remedial action objectives and specific remediation goals for both groundwater and soil were discussed in
Section 7 of this Decision Summary, The selected remedy is expected to achieve remediation goals for soil
within five years and for groundwater within twenty years. The expected durations of the components of the
selected remedy are based upon findings of the treatability study, and assume that DNAPLS are not present.
The presence of DNAPLs could significantly lengthen the remediation timeframe. A specific remediation
timeframe analysis was not conducted as part of the FS.
The selection of this remedy is based upon the comparative analysis of alternatives presented above, and
provides the best balance of tradeoffs with respect to the nine evaluation criteria. With regard to soil treatment,
alternative S-2A is the best choice because it provides an equally high level of protectiveness
27
-------
as alternative S-1 A, but is available at a much lower cost. In addition, there is an existing soil vapor extraction
system owned and used by EPA at another CERCLA site in Nebraska, which could be easily adapted to this
source area. With regard to groundwater treatment, alternative G-1 was selected over alternative G-2 because
it provides an equally high level of protectiveness at a much lower cost. Alternative G-3 is available at a lower
cost, but was not selected because it is not as protective as G-1. In addition, there are some implementability
concerns with alternative G-3.
A cost summary is provided as Table 9-1 for components of the selected remedy. These cost estimates are
based on results of the treatability study and a series of assumptions based on professional judgement. Some
modifications may be made to the remedy during remedial design and/or construction which could impact the
cost of the remedy. The total present worth cost of this remedy is $929,250 without treatment of the air
discharge. If treatment of the air discharge is required, initial capital cost of the remedy could increase by
$56,750 and the annual O&M cost could increase by $13,638. Itemized cost estimates can be found in the FS
Report.
28
-------
Table 9-1
Cost Summary for the Selected Remedy for One Hour Martinizing
Remedy Component
Estimated Cost
Groundwater Use Restrictions
$15,000
Alternative S-2A:
SVE System (capital costs)
Contingencies (10%)
Annual O&M
$234,100
$22,000
$70,766
Alternative G-1:
Groundwater Extraction System and Air Stripper
(Capital costs)
Contingencies (10%)
Annual O&M
$159,150
$14,300
$17,082
Present Worth Cost (8% interest rate)
$929,250
29
-------
Liberty Services and Ideal Cleaners Source Areas:
The selected remedy for these source areas is Alternative M-2B calling for monitoring and institutional controls
with a contingency for soil vapor extraction and treatment by carbon adsorption. Components of the remedy
are listed below.
•• Groundwater monitoring for 10 years (natural attenuation)
>• Institutional controls to restrict groundwater use
» Soil vapor extraction and treatment as a contingency
EPA believes the processes of natural attenuation will be sufficient to reduce contaminant levels in the
groundwater, provided there are no continuing releases of contaminants to the subsurface soils. In combination
with groundwater use restrictions, this remedy will be protective of human health.
The institutional controls will involve restrictions on the installation of new groundwater wells for private use in
the area of contamination and long-term groundwater monitoring. Restrictions will be designed to prevent the
use of shallow groundwater for drinking water and other household uses, and will call for the registration of new
wells in the area of contamination. The city of Grand Island will be responsible for passing and enforcing the
necessary ordinances. Groundwater monitoring will include the installation of one new monitoring well placed
downgradient of each source area and routine sampling of these wells and existing wells to track the movement
of the contaminant plumes. The natural processes of microbial degradation and dilution will be allowed to
attenuate contaminant levels.
The contingency provides for treatment of the source soils to enhance overall cleanup at these source areas.
However, the contingency action will only be implemented if monitoring does not demonstrate a continual
reduction of contaminants in the groundwater to the extent that residual contaminant levels present a threat to
human health or the environment. The concentration of contaminants in the groundwater that would trigger
implementation of the contingency has not been specified. Rather, the decision to implement the contingency
will be based upon several factors including monitoring results showing trends in groundwater contaminant
levels, risks associated with the residual contaminant levels, the effectiveness of groundwater use restrictions,
and any new information regarding continuing releases of contaminants to the environment. The contingency
may be implemented if monitoring results indicate that levels of PCE in the groundwater are increasing. In that
event, EPA would re-evaluate the risks to human health and the environment and may implement the
contingency action if the human health risk exceeds 1x10"4 for carcinogens or if the hazard index for
noncarcinogens exceeds 1.0.
Remedial action objectives and specific remediation goafs for both soil and groundwater are discussed in
Section 7 of this Decision Summary. Given the low levels of contaminants found in the soils at these source
areas, the remedial action objectives for soil have already been achieved. It is expected that the remediation
goals for groundwater will be achieved within 10 years.
The selection of this remedy is based upon the comparative analysis of alternatives presented above, and
provides the best balance of tradeoffs with respect to the nine evaluation criteria. The selected remedy is the
most protective because it combines the features of two alternatives to address groundwater and soil. While
the two soil treatment alternatives offer a high degree of protectiveness with regard to soil exposures, they do
not address threats associated with contaminated groundwater at these two source areas. However, given the
low concentrations of contaminants at these source areas, EPA believes that the processes of natural
attenuation will be sufficient to reduce contaminant levels to below remediation goals within ten years. For this
reason, the level of long-term effectiveness provided by the selected remedy is high. The selected remedy will
reduce contaminant volume and mobility over time. None of the alternatives evaluated would reduce
contaminant toxicity. The selected remedy offers a moderate to high degree of short-term effectiveness
depending on whether the contingency is implemented. All of the alternatives, with the exception of G-4, are
highly implementable. Alternative G-4 has some implementation concerns relating to the capacity and
condition of city sewer lines and the level of city, state, and federal coordination required.
30
-------
A cost summary is provided as Table 9-2 which contains components of the selected remedy. These cost
estimates are based on results of the treatability study and a series of assumptions based on professional
judgement. Some modifications may be made to the remedy during remedial design and/or construction which
could impact the cost of the remedy. The total present worth cost of this remedy is $291,800 which reflects the
cost of a groundwater monitoring program at both source areas and the cost of one soil vapor extraction unit
which would be used at one source area and then moved to the other source area. Itemized cost estimates
can be found in the FS Report.
31
-------
Table 9-2
Cost Summary for the Selected Remedy for Liberty and Ideal Cleaners
Remedy Component
Estimated Cost
Groundwater Use Restrictions
$15,000
Groundwater Monitoring:
Capital Costs
Contingencies (10%)
Annual O&M
$15,500
$2,900
$16,200
Contingency Alternative S-2B:
SVE System Capital Costs
Contingencies (10%)
Annual O&M
$62,600
$5,600
$22,264
Present Worth Cost (8% interest rate)
$291,800
32
-------
10. STATUTORY DETERMINATIONS
EPA's selected remedial actions for Superfund sites must meet several requirements set forth in Section 121
of CERCLA. These requirements include the following:
• Be protective of human health and the environment;
• Comply with ARARs (or justify an ARAR waiver);
• Be cost-effective;
• Utilize permanent solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable; and
• Satisfy the preference for treatment that reduces toxicity, mobility, or volume as a principal
element, OR provide an explanation as to why this preference is not satisfied.
The following sections discuss how the selected remedies for the One Hour Martinizing source area and then
the Liberty and Ideal Cleaners source areas meet these statutory requirements.
One Hour Martinizing Source Area:
Protection of Human Health and the Environment
This requirement is achieved by the selected remedy through the removal and treatment of contaminants from
subsurface soils and groundwater. Human health risks which may be associated with exposure to
contamination at this source area will be reduced to a level considered by EPA to be protective. EPA estimates
that contaminant levels in the groundwater will be reduced to the levels considered safe for human
consumption (MCLs) within twenty years. In the short term, protection is provided by groundwater use
restrictions which will prevent exposures to the contaminated groundwater. Protection of the environment is
also achieved by this remedy through the removal of contaminants from subsurface soils which will eliminate
a continual point source of contamination to the groundwater. Air emissions and treated water discharges will
be managed according to the appropriate federal and state regulation, providing for continued protection of the
environment during implementation of the remedy.
Compliance with ARARs
The selected remedy is expected to comply with ARARs. Maximum Contaminant Levels (MCLs) established
under the Safe Drinking Water Act are considered relevant arid appropriate for the groundwater treatment
component of the selected remedy for the contaminants of concern. Groundwater will be extracted and treated
to below MCLs. However, if DNAPL zones are located at the site, a waiver of ARARs may be sought based
on technical impracticability of achieving MCLs in DNAPL zones. Nebraska Title 118 contains the state
groundwater quality standards, which, for the contaminants of concern at this site, are the same as MCLs, and
are applicable to the selected remedy.
With regard to the discharge of treated water, provisions of the Clean Water Act and several state laws
including Title 117 (surface water quality criteria), Title 119 (NPDES permits), Title 121 (effluent standards),
Title 127 (pretreatment), and Title 179 (public water supply systems) are applicable. Nebraska Title 178
governing water well licensure and drilling and pump installation is also applicable to the installation of the
groundwater extraction system.
Provisions of the Clean Air Act and Nebraska Title 129, Air Pollution Control Rules and Regulations, may be
applicable depending upon the concentration of hazardous air pollutants in the air streams being discharged
from the SVE system and the air stripping unit. If the concentrations of hazardous air pollutants do not exceed
the levels which trigger certain permitting and control requirements, the requirements will not be applicable,
but may be considered relevant and appropriate. The applicability or appropriateness of these laws to the
33
-------
actions being conducted at this source area will be assessed following air monitoring to be conducted upon
start-up of the remedy.
Some RCRA requirements may apply to the handling of solid wastes and the identification and handling of any
hazardous wastes which may be generated during well drilling activities. Similarly, Nebraska Title 126
(management of wastes) and Title 132 (solid waste management) will also be applicable. Any such wastes
will be transported offsite for disposal. Appropriate Department of Transportation regulations will be followed
during offsite shipment of wastes, although these requirements are not considered ARARs. Similarly, the
CERCLA Offsite Rule and Land Disposal Restrictions under RCRA will be followed, but are not ARARs as they
apply to an offsite action rather than an onsite action.
Requirements of the Occupational Safety and Health Act (OSHA) will be complied with, but are not ARARs
because OSHA is not an "environmental" law.
Cost Effectiveness
EPA believes the selected remedy is cost-effective because the effectiveness of the remedy in terms of its
ability to mitigate the principal threats at the site is in proportion to its cost ($929,250). Less costly alternatives
were evaluated, but did not meet the NCP criteria for protection of human health and the environment. Other
alternatives which did meet the NCP criteria were more costly than the selected remedy without additional
benefit. The selected remedy provides an effective solution to address the threats at the site at a reasonable
cost.
Utilization of Permanent Solutions and Alternative Treatment Technologies or Resource Recovery
Technologies to the Maximum Extent Practicable
The selected remedy represents the maximum extent to which permanent solutions and treatment technologies
can be utilized in a cost-effective manner at this source area. Of the alternatives that are protective of human
health and the environment and comply with ARARs, EPA has determined that the selected remedy provides
the best balance of trade-offs in terms of long-term effectiveness, reduction of toxicity, mobility, or volume
achieved through treatment, short-term effectiveness, implementability, and cost. Additional considerations
include the statutory preference for treatment as a principal element as well as state and community
acceptance.
Given that the alternatives involving treatment as a principal element provide a high degree of overall
effectiveness and have similar characteristics in terms of short-term effectiveness, reduction of toxicity, mobility,
and volume, and do not have many implementability concerns, cost played a significant role in differentiating
between the alternatives. On the other hand, alternatives NA-1A and M-1A which do not include treatment,
were not selected because they do not meet the threshold criteria. Alternative G-3does not contain a treatment
component and does not offer as high a degree of protectiveness as the selected remedy, although it could
be implemented at a lower cost. In this case, the trade-off involved selection of a higher cost remedy in order
to better protect human health and the environment. Implementability concerns and the lack of a treatment
component under alternative G-3 also contributed to it not being selected.
The state of Nebraska, through the NDEQ, agrees with the selected remedy and participated in the public
hearing to indicate its support. In general, members of the public showed support for the selected remedy.
Members of the public or the NDEQ did not indicate a lack of support for the other alternatives, but probably
would not have been satisfied with alternatives which do not include treatment. There seems to be general
recognition that site conditions justify treatment, and selection of the lower cost alternatives to achieve a high
degree of effectiveness is favorable.
34
-------
Preference for Treatment as a Principal Element
The selected remedy satisfies the statutory preference for treatment as a principal element. The principal
threats at the source area include contaminated subsurface soils which act as a continual point source of
groundwater contamination, and the threat of human ingestion of contaminated groundwater. The selected
remedy includes treatment components addressing both contaminated subsurface soils and groundwater.
Liberty and Ideal Cleaners Source Areas:
Protection of Human Health and the Environment
The selected remedies for these source areas meet this requirement by providing for the prevention of human
consumption of contaminated groundwater through use restrictions and the processes of natural attenuation
to reduce contaminant levels to below MCLs within ten years. A groundwater monitoring program is included
to monitor contaminant levels overtime and confirm the adequacy of natural attenuation to reduce contaminant
levels. A contingency action is also included for the treatment of source soils which would provide increased
protection of the environment by eliminating a source of groundwater contamination.
Attainment of ARARs
The selected remedy is expected to comply with ARARs. Because the selected remedy does not involve a
groundwater extraction/treatment component, Maximum Contaminant Levels (MCLs) established under the
Safe Drinking Water Act are not applicable, but are considered relevant and appropriate and constitute the
remediation goals for groundwater. Contaminant levels are expected to naturally attenuate to below MCLs
within ten years. The groundwater monitoring program will evaluate the effectiveness of natural attenuation
processes in achieving MCLs as ARARs. Nebraska Title 118 contains the state groundwater quality standards,
which, for the contaminants of concern at this site, are the same as MCLs, and are also relevant and
appropriate requirements for the selected remedy. With regard to the installation of groundwater monitoring
wells, Nebraska Title 178 governing water well licensure and drilling is applicable.
If the contingency action is implemented, provisions of the Clean Air Act and Nebraska Title 129, Air Pollution
Control Rules and Regulations, may be applicable depending upon the concentration of hazardous air
pollutants in the air streams being discharged from the SVE system. If the concentrations of hazardous air
pollutants do not exceed the levels which trigger certain permitting and control requirements, the requirements
will not be applicable, but may be considered relevant and appropriate. The applicability or appropriateness
of these laws to the actions being conducted at these source areas will be determined following air monitoring
to be conducted upon start-up of the contingency.
Some RCRA requirements may apply to the handling of solid wastes and the identification and handling of any
hazardous wastes which may be generated during well drilling activities. Similarly, Nebraska Title 126
(management of wastes) and Title 132 (solid waste management) will also be applicable. Any such wastes
will be transported offsite for disposal. Appropriate Department of Transportation regulations, the CERCLA
Offsite Rule and Land Disposal Restrictions under RCRA will be followed, but are not ARARs as they apply to
a offsite actions rather than onsite actions.
Requirements of the Occupational Safety and Health Act (OSHA) will be complied with, but are not ARARs
because OSHA is not an "environmental" law.
Cost Effectiveness
EPA believes the selected remedy is a cost-effective solution to address the threats posed by contamination
at these two source areas. Given the low levels of contamination present at these source areas, EPA believes
that the processes of natural attenuation, in combination with institutional controls to restrict groundwater use,
will be protective of public health and the environment. The cost associated with the selected remedy is in
35
-------
proportion with the benefit it provides in terms of overall effectiveness. More costly alternatives involving soil
treatment and/or groundwater extraction provide greater short-term effectiveness, but do not justify the
additional cost. Implementation of the contingency action would increase the cost, but will only be implemented
if monitoring shows natural attenuation not to be effective in reducing groundwater contaminant levels.
Utilization of Permanent Solutions and Alternative Treatment Technologies or Resource Recovery
Technologies to the Maximum Extent Practicable
While the selected remedy only involves treatment as a contingency action, the remedy provides for the
permanent reduction of contaminant levels in the groundwater through the processes of natural attenuation.
Conditions at these source areas do not justify more costly alternatives calling for aggressive soil or
groundwater treatment. For this reason, the selected remedy is considered to meet this requirement to the
maximum extent practicable.
In the evaluation of alternatives with respect to the NCP criteria, the primary trade-offs involved varying degrees
of short-term effectiveness, reduction of toxicity, mobility, and volume, and cost. Alternatives involving soil
treatment or groundwater extraction offer advantages in short-term effectiveness and reduction of toxicity,
mobility, and volume, but come at a substantially higher cost than the selected remedy and are not necessary
to mitigate the threats posed by the low levels of contaminants found at these source areas.
Preference for Treatment as a Principal Element
The selected remedy does not directly meet this requirement as treatment of source soils will only be
implemented as a contingency action if natural attenuation does not prove effective. Given the low contaminant
levels and associated risks at these source areas, EPA does not believe that treatment is required or that the
additional costs for treatment are justifiable.
11. DOCUMENTATION OF SIGNIFICANT CHANGE
The proposed plan was released for public comment on February 15, 1996. It identified EPA's preferred
alternative for the groundwater at the One Hour Martinizing source area as groundwater extraction and
treatment by ori-site air stripping (Alternative G-1). Alternative G-1, as presented in the proposed plan, did not
contain institutional controls or groundwater monitoring. However, the discussion and evaluation of alternative
G-1 in the feasibility study, which is contained in the administrative record, included the institutional controls and
groundwater monitoring that are part of the selected remedy. Monitoring and institutional controls at the One
Hour Martinizing source area were also presented as a separate alternative (M-1 A) in the proposed plan. EPA
has determined that including institutional controls and groundwater monitoring as part of alternative G-1 will
allow it to achieve a higher degree of protection of human health and the environment.
36
-------
RESPONSIVENESS SUMMARY
Cleburn Street Well Site
Grand Island, Nebraska
The public comment period on the preferred alternative began February 15,1996 and ended March 16,1996.
No written comments from the public were received during the comment period.
A public hearing was held in Grand Island, Nebraska on February 27,1996 with several members of the public
in attendance. In general, the public was supportive of the selected remedies. No comments were received
suggesting changes in or opposing the selected remedies. However, there was some concern expressed
regarding the poor condition of an abandoned property at the One Hour Martinizing source area. EPA indicated
its support for the sale and redevelopment of the subject property, and emphasized that a letter of comfort was
previously provided to the city to assist in the sale of the property.
37
-------
Record of Decision Appendix A
Cleburn Street Well Site
TABLE 2-3 SUMMARY OF CHEMICALS OF POTENTIAL CONCERN AT THE CLEBURN STREET WELL SITE
\
Sur f ,ir o Si> i 1
R.itigu of H.ui(;e (if
Kiui|. of Detected Detect Ion* •' '
Detection V.ilne:,. MI;, kn limit', in/', kc.
Clu-inical
llen^ene
Bromodi. It l»i IHII.-I h.inc
Bromofoim
Ctirhon t et t .ichlni nle
Chloroi oini
Dibromocli l.n onn-'l li.iiie
Dichloroethane, 1. 1
Dichloroethylene, 1.2, Total
Diclilotoetliylcne. 1 , 1
Kthy H..-II.'. i.i-
Hexanune, .!
Methyl-2- t'entanuiie, 4-
Tetrachloroethylene
Toluene
Ivj Trjchloiotl li.me . 1 . 1 , 1 -
1 Trlchloroethan^.1,1,2-
Trlchloroethylene
Xylenes, Total
Hits
0
0
0
0
0
0
0
1
0
0
0
0
u
0
0
0
2
0
Total Min
.,
21
21
21
21
21
21
21 0.083
21
21
21
21
21 0.018
21
21
21
21 0.016
21
M.ix Min
II Ihli.i.
0 UOi.l.
0 0066
00006
0 00i,6
O.OUOb
0 0066
0.083 0 0066
0 0066
0 Ollf. 6
001]
0.013
2.8 O.OOBJ
0.0066
0.0066
0.0066
0.12 0 0066
0.0066
M.ix
„ ,,,...
0 II H
0.014
0.014
0 .014
0 II H
0014
0.014
0.014
0014
0 O.'.ll
0.028
0.014
0.014
0 014
0.014
0.014
0 014
K l tf c
Subsui face Sui 1
Range of
I ot Dulcet cd
)>etecl.ion
Hits
0
0
0
0
1
0
0
1 .
1
0
0
0
12
0
1
1
2
1
Total
41
41
41
41
41
41
41
41
41
41
41
41
41
41
41
41
41
41
V.I 1 III!
Mln
0.014
0.048
0.78
0.0065
3.1
0.033
0.03
0.005?
Range of
Dot.«cl Ion
Fr»q. of
Groiindw.itiM
Range of
Dot ocl...l
i mii/rfi 1 mills. itiH/kii Detection v.i|u,>
Max
0.014
0.048
0.78
9.200
3.1
0.033
4.4
0.0057
Mln
il OO1).!
0 0052
0 0052
0 0052
0 0052
0 0052
0 0052
0.0052
0.0052
0 0052
0 01
0 01
0.0052
0.0032
0.0052
0.0052
0 0052
0.0052
Max
0 OH
0 014
0.014
0.014
0.0098
0.014
0 014
0.0098
0.0098
23
0.0.!7
0.027
0.008?
23
0.0098
0.0098
0.0098
23
(fit*
2
3
4
1
3
2
4
5
4
4
1
1
16
5
6
6
8
3
Jotal
32
32
32
32
32
32
32
32
32
32
32
32
32
32
32
32
32
Mm
0 002
0.001 1
0.0008
0.005
0.001 (.
O.OOI
0.002
0.0028
0.002
0.003
0.005
0.012
0.0032
0.0009
0.002
0.002
0.002V
0.0017
. '»!* '
0 (!.'
0 Oil 1
0.007
0.005
0.017
0 002/
0.0091
0.16
0.037
0.028
0 005
0 012
150
0.45
0.54
0.012
0.41
1.7
Range of
Del
-------
-------
------- |