United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R07-91/051
September 1991
Superfund
Record of Decision
Shaw Avenue Dump, IA
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50272-101
REPORT DOCUMENTATION 11. REPORT NO.
PAGE EPA/ROD/R07-91/051
I ~
3. Recipient's Acceaalon No.
4. Tille and Subtitle
SUPERFUND RECORD OF DECISION
Shaw Avenue Dump, IA
First Remedial Action
7. Author(a)
5. Report Date
09/26/91
6.
8. Perfonning Organization Repl No.
9. Perfonning Orgainization Name and Address
10. ProjectlTaaklWork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
1~ Sponsoring Organization Name and Address
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report a. Period Covered
Agency
800/000
14.
15. Supplementary Noles
.-
16. Abstract (Limit: 200 wolda)
The 26-acre Shaw Avenue Dump site is a chemical waste site in Charles City, Floyd
County, Iowa. Land use in the area is predominantly residential. Part of the site
lies within the 100-year floodplain of the Cedar River, and a wetlands area is
located approximately 600 feet south of the site. From 1899 to 1964, Charles City
used the site as a municipal landfill for waste incineration, and disposal of liming
sludge from the city's publicly owned treatment works (POTW) and asphaltic materials
cont~nue to be disposed of in the landfill. Additionally, from 1949 to 1953,
chemical wastes generated by chemical batch processing of arsenic and compounds used
in the production of animal pharmaceuticals at Salsbury Laboratories were disposed of
on site. Between 1977 and 1981, the State issued reports based on studies of the site
and surface water that documented elevated levels of metals in an abandoned gravel
pit near the site. Approximately 14,000 to 28,000 cubic feet of chemical waste and
10,000 tons of solid waste from the POTW, including sludge containing hazardous waste
from Salsbury Laboratories, and associated contaminated soil are currently present
on site. Leaching of contaminants, especially arsenic, from 370 cubic yards of
chemical fill and adjacent soil into ground water is thought to be the pricipal
(See Attached Page)
17. Document Analysla a. Deacriptors
Record of Decision - Shaw Avenue Dump, IA
First Remedial Action
Contaminated Media: soil, debris
Key Contaminants: VOCs (benzene, toluene,
(arsenic, lead)
xylenes), other organics (PARs), metals
b. Identifiera/Open-Ended Terms
c. COSA 11 RelcflGroup
18. Availabitity Statement
19. Security Class (This Report)
None
20. Security ClUB (ThIs Page)
M"no
21. No. of Pages
47
I
~ Price
(See ANSl-Z39.18)
See IlIIttrucliolllt on Re-
272 (4-77)
(Formerty NTIS-35)
Department of Commerce
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EPA/ROD/R07-91/051
Shaw Avenue Dump, IA
First Remedial Action
Abstract (Continued)
threat at the site. A 200-gallon underground storage tank (UST) is located within the
vicinity of the chemical fill, and also is considered to be a possible source of onsite
contamination. This Record of Decision (ROD) addresses the chemical fill and
surrounding contaminated soil, and the underground gasoline tank as Operable Unit 1
(OU1). A future ROD will address contaminated ground water as OU2. The primary
contaminants of concern affecting the soil and debris are VOCs including benzene,
toluene, and xylenes; other organics including PARs; metals including arsenic and lead;
and other inorganics.
The selected remedial action for this site includes treating the chemical fill and soil
using in-situ fixation and stabilization, followed by constructing a low permeability
cap over the fixed and stabilized fill; conducting treatability studies to determine the
effectiveness of the treatment, and if treatment is not effective, issuing an ESD and
disposing of the waste offsite; removing and disposing of offsite the underground
gasoline tank; monitoring ground water quality; and implementin~ institutional controls
including deed restrictions, and site access restrictions including fencing. The
estimated present worth cost for this remedial action is $513,400, which includes an
annual present worth O&M cost of $65,550.
PERFORMANCE STANDARDS OR GOALS: Action-specific soil clean-up goals are based on State
and Federal standards, RCRA Land Disposal Restrictions, OSHA, RCRA Toxic Characteristic
Leachate Procedure, and UST regulations, and include arsenic 50 mg/kg and cadmium
20 mg/kg.
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RECORD OF DECISION
SHAW AVENUE DtJKP
CHARLES CITY, IOWA
Declaration
1.0
Site Name and Location
Shaw Avenue Dump site
Charles City, Floyd County, Iowa
Statement of Basis and Purpose
1.1
This decision document presents the selected remedial action
for the chemical fill and contaminated soil at the Shaw Avenue
Dump Site, located in Charles City, Floyd County, Iowa, and was
developed in accordance with the requirements of 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, the National oil and Hazardous Substances Pollution
Contingency Plan (NCP), 40 CFR Part 300 (1990). This decision
document explains the factual and legal basis for selecting the
remedy for this Site.
The Iowa Department of Natural Resources (IDNR) concurs with
the selected remedy. The remedial action decision is based on
the Administrative Record, which is available for public review
at the Charles City Public Library, 106 Milwaukee Mall, Charles
City, Iowa, and at the u.S. Environmental Protection Agency (EPA)
Regional Office located at 726 Minnesota Avenue, Kansas City,
Kansas.
1.2
Assessment of the site
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare,
or tQe environment.
1.3
Description of the Selected Remedy
EPA has decided to divide this site into two operable units.
Operable unit one will address the chemical fill and surrounding
contaminated soil. Operable unit two will address contaminated
ground water. The remedy involving the first operable unit is
presented in this ROD. The remedy involving the second operable
unit will be presented in a future ROD.
The chemical fill and surrounding contaminated soil present
the principal threat at the Shaw Avenue Dump site and are
considered the source of contamination in the ground water. The
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2
major components of the selected remedy for soil, which is
designed to address the chemical fill and soil contamination,
include the following:
-Fixation/stabilization of chemical fill and contaminated
soil;
-Installation of a low permeability cap to protect the
fixated/stabilized material: and
-Ground water monitoring will be continued during and after
implementation of the fixation/stabilization remedy to
determine the effectiveness of the remedy in preventing
leaching of contaminants to the ground water.
If treatability testing shows that stabilization/fixation is
ineffective for the chemical fill and contaminated soil then this
material will be excavated and removed to a RCRA approved
landfill as described in alternative 7.1.3 in the Description of
Alternatives contained in this ROD.
1.4
Declaration of statutory Determinations
The selected remedy is protective of human health and the
environment, complies with federal and state requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment technologies to the
maximum extent practicable for the chemical fill and contaminated
soil, and it satisfies the statutory preference for remedies that
employ treatment that reduces toxicity, mobility, or volume as
their principal element. The contingency remedy complies with
all of the statutory requirements with the exception that under
the current land disposal restrictions it does not require
treatment to reduce toxicity, mobility, or volume. However, in
May of 1992 the Land Disposal Restrictions will require treatment
prior to disposal of these materials.
Because this remedy will result in hazardous substances
remaining onsite above health-based levels, a review will be
conducted within five years after commencement of remedial action
to ensure that the remedy continues to provide adequate
protection for human health and the environment.
n
Mor' Kay
Regional Administrator
u.s. EPA. Region VII
1~!e~(
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DECISION SUMMARY
1.0
Site Name, Location and Description
The Shaw Avenue Dump Site (Site) is located on the
southeastern edge of Charles City, Iowa, approximately 600 feet
from the Cedar River, near the intersection of Shaw Avenue and
Clark Avenue (Figures 1 and 2). The Site occupies approximately
twenty-four acres of the Cedar River 100-year flood plain. The
site is owned by the City of Charles City. The Charles City
waste water treatment plant (POTW) is immediately east of the
site.
The site runs northeast to southwest with a ~ength of
approximately 2,000 feet and a width of approximately 525 feet.
The Iowa Terminal Railroad tracks bound the site to the west.
The site is fenced on the north and east sides and is bordered by
the Cedar River to the south. Figure 3 presents the locations of
private wells near the Site.
2.0
Site History and Enforcement Activities
Charles City purchased the northern portion of the Site in
1899 and continued to acquire sections of it until 1964. A
municipal landfill was operated on the site from sometime prior
to 1949 until 1964 and the Site continues to be used for disposal
of liming sludge from Charles City's POTW. The Site was also
used by Salsbury Laboratories, Inc., (now Solvay Animal Health,
Inc.), from 1949 to 1953 to dispose of chemical waste generated
by chemical batch processing of arsenic and compounds used in
Salsbury's production of animal pharmaceuticals. On December 31,
1989, Salsbury Laboratories, Inc. merged with Solvay Veterinary,
Inc. to form Solvay Animal Health, Inc.
Liming sludge from the Charles City POTW was disposed of at
the site from 1949 to 1964. The City's POTW received liquid
industrial waste from Salsbury during the period the City
disposed of its sludge at the site. Salsbury's liquid waste
during this period included arsenic, nitrophenol,
orthonitroaniline, nitrobenzene, and 1,l,2-trichloroethane.
There is no evidence that anyone but Salsbury Laboratories sent
hazardous waste to the City's POTW. Therefore, salsbury's waste
was present in the sludge disposed of by the City at the Site.
The quantity of chemical waste disposed of by Salsbury at the
Site is estimated to be between 14,000 and 28,000 cubic feet and
the quantity of solid waste disposed of at the site from the
City's POTW for the period from 1949 to 1964 is estimated to be
~o,OOO tons.
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The site was identified as a potential hazardous waste site
by the Iowa Department of Environmental Quality (IDEQ) in 1977.
The IDEQ studied the Site and documented arsenic contamination in
surface water in an abandoned gravel pit near the Site in several
reports issued between 1977 to 1981.
The site was placed on the National Priorities List (NPL) in
July 1987. A Remedial Investigation/Feasibility Study (RI/FS)
was initiated in ~u1y 1988 and field work was completed in June.
1990. The RI report was finished in June 1990 the Risk
Assessment was completed in April 1991 and the FS report was
completed in June 1991.
3.0
Highlights of community participation
The Administrative Record and the Proposed Plan for the Shaw
Avenue Dump Site were released to the public for comment on July
12, 1991. The RI and FS Reports were made available to the
public in the Administrative Record at both an information
repository maintained at the EPA Docket Room at the Region VII
offices and at the Charles City Public Library, Charles City,
Iowa. The notice of availability for these two documents was
published in The Charles City Press on July 12, 1991. The public
comment period on the Proposed Plan ran from , July 12, 1991, to
August 12, 1991. In addition, a public meeting was held in
Charles City, on July 24, 1991. At this meeting, representatives
from EPA, Iowa Department of Natural Resources (IDNR), Iowa
Department of Health (IDOH) and the Agency for Toxic Substances
and Disease Registry (ATSDR) presented information and answered
questions about the Site and the remedial alternatives under
consideration. Responses to the comments received during the
public comment period are included in the Responsiveness Summary,
which is part of this ROD. The decision for this Site is based
on the Administrative Record.
4.0
Scope and Role of Response Action within site strategy
As noted above, on July 12, 1991, EPA issued the Proposed
Plan for the Shaw Avenue Dump Site. The Proposed plan presented
EPA's preferred remedial alternative for both the chemical fill
and surrounding contaminated soil as well as the contaminated
ground water at the site. EPA has reviewed all of the public
comments received during the public comment period and on the
basis of those comments has decided to separate the remedy for
this Site into two operable units. Operable unit one will
address the chemical fill and surrounding contaminated soil.
Operable unit two will address contaminated ground water. This
sequencing of the operable units will allow the chemical fill and
contaminated soil to be addressed resulting in a significant risk
reduction. Ground water monitoring will continue during and'
after implementation of the first operable unit. After ground
water monitoring data is analyzed following implementation of the
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first operable unit the plans for the second operable unit will
be finalized. This ROD contains EPA's selected remedy for
operable unit one. At some point in the future, EPA will issue
another Proposed Plan that will present EPA's preferred remedial
alternative for operable unit two. At that time, the public will
be given an opportunity to comment on all of the alternatives
presented in the Proposed Plan.
As with many Superfund sites, the problems at the Shaw
Avenue Dump site are complex. The chemical fill and contaminated
soil present the principal threat at the site as a result of
leaching of contaminants to ground water and the possible risk of
exposure to future residents or onsite workers. The selected
remedy uses fixation/stabilization to address the principal
threat. The Remedial Investigation identified the source of
contamination at the Site to be the chemical waste disposed of at
the Site by Salsbury Laboratories. The threat posed by the
present levels of arsenic in soil and ground water is of
particular concern.
The response action selected in this ROD addresses the
principal threat posed by the chemical fill and contaminated soil
at the Site and is intended to constitute final action for the
chemical fill and contaminated soil at this site.
The cleanup objectives of this remedial action are to
eliminate or reduce to an acceptable level the risks posed by
exposure to the contaminated soil and chemical fill and to
eliminate or reduce the potential migration of contaminants into
ground water. To accomplish this objective the contaminated soil
and chemical fill will be fixated/stabilized or excavated and
removed to a RCRA landfill to prevent further releases of
hazardous substances as well as exposure to the hazardous
substances. These risks were identified by the baseline risk
assessment performed for the Shaw Avenue Dump Site.
5.0
Summary of site Characteristics
. The nature and extent of contamination of chemical. fill and
soil at the Shaw Avenue Dump Site is summarized in this section.
This summary is based primarily on data generated by the work
performed pursuant to the RI/FS. Detailed information regarding
the nature and extent of contamination is contained in the final
RI report (June 1990), which is part of the administrative record
for this Site.
5.1
soil and Chemical Pill
The areal and vertical extent of chemical fill and
associated soil contamination was estimated by. analyzing samples
from soil borings, monitoring wells and trenching conducted
during the RI/FS. Chemical fill was identified in three waste
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cells around a city-owned maintenance facility located in the
northern portion of the Site. The chemical fill is located
approximately two to three feet below the ground surface and
extends vertically to bedrock. The thickness of the chemical
fill encountered ranges from .5 to 9.5 feet. The total volume of
chemical fill was calculated to be 370 cubic yards with
additional contamination in the adjacent soil.
The chemical fill exhibits characteristics of process wastes
generated by Salsbury Laboratories from 1949 to 1953. Analyses.
of samples collected from the chemical fill during the RI
revealed high levels of arsenic, cadmium, chromium, lead and
volatile and semi-volatile organic compounds including methylene
chloride, 1, 1, 2-trichloroethane, and orthonitroaniline as
detailed in Table 4. Concentrations of metal contaminants were
highest in the waste material itself, with lesser, but still
elevated, concentrations in the soil around the chemical fill.
The chemical fill and contaminated soil is considered to be the
source of contamination in the ground water.
A 200 gallon underground gasoline storage tank is located in
the vicinity of the chemical fill. The tank is owned by the city
and used as a fuel source for City vehicles. It is considered to
be a possible source of benzene, toluene, xylene, apd manganese
in soil and ground water.
The chemical fill is located in the alluvium that overlies
the Upper Cedar Valley formation. The Cedar Valley is a
limestone formation. An extremely fractured and weathered
limestone layer exists at the surface of the Cedar valley
formation. The Upper Cedar Valley formation is hydrologically
separated from the Lower Cedar valley formation by a relatively
impermeable shale unit. The Upper Cedar Valley aquifer underlies
the entire site. There is also an unconfined alluvial aquifer in
the southern portion of the site.
Analyses of surface soil samples showed high levels of
polycyclic aromatic hydrocarbons (PAHs) and heavy metals
in~luding arsenic, beryllium, and cadmium as detailed in' Table 2.
Analyses of subsurface soil samples showed high levels of PAHs
and metals including arsenic, cadmium, and lead as detailed in
Table 3. The concentrations of PAHs are typical of those
resulting from the burning of municipal wastes and the disposal
of asphaltic materials and are in the area of the Site where
municipal wastes were burned and asphaltic materials were
disposed by the city. Adqitional sampling and analysis will be
conducted during the remedial design to determine the extent of
contamination in the surface soils since these concentrations
were based on composite sampling.
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5.2
Ground water
Ground water flow direction in the Upper Cedar Valley
aquifer is typically west to southwest along the northern and
southwestern portions of the site and to the south along the
southeastern portion of the site to the Cedar River. During
periods of heavy snow melt or heavy precipitation, a temporary
ground water flow divide is created in the northern portion of
the Site and flow direction is both west/southwest and
east/northeast. Ground water flow in the unconfined alluvial
aquifer is generally towards the Cedar River. However, during
periods of high river flow, the flow direction in the northern
portion of the site will reverse and the alluvial aquifer will be
recharged by the Cedar River. The Cedar River is the discharge
point for the unconfined alluvial aquifer and the Upper Cedar
Valley aquifer. -
"
Borings completed at the Site revealed several hydraulically
separate water bearing units. These include a local perched
aquifer at the northern end of the Site, an unconfined alluvi~
aquifer, an unconfined upper bedrock aquifer (the Upper' Cedar
Valley), and a lower bedrock aquifer (the Lower Cedar Valley).
The Upper and Lower Cedar Valley formations are separated by the
Chickasaw Shale which acts as a confining unit, preventing flow
from the upper unit to the lower unit. An upward hydraulic head
also prevents flow from the upper to the lower bedrock aquifer.
Fifteen monitoring well nests were installed at the site
during the RI/FS. The location of the well nests are illustrated
in Figure 4. The investigations conducted during the RI
identified distinct areas of ground water contamination at the
Site. High levels of volatile organic compounds including vinyl
chloride, 1,1-dichloroethene, 1,2-dichloroethane, and 1,1,2-
trichloroethane were detected in ground water monitoring wells at
the southern end of the site. In the northern and central
portions of the Site, the ground water was contaminated with
heavy metals including arsenic. Benzene, toluene, and xylene
were also detected in the northern portion of the site. The
benz~ne, toluene and xylene may come from an underground storage
tank'located on the site. A complete list of compounds detected
in the ground water is presented in Table 1. EPA's selected
remedial alternative for the contaminated ground water will be
presented in a Proposed Plan to be issued some time in the
future. '
6.0
Summary of site Risks
6.1
overview of Baseline Risk Assessment
A baseline risk assessment was conducted as required by
CERCLA to evaluate the potential impacts to human health and the
environment posed by Site contaminants absent a remedial action
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(i.e., if the site were not cleaned up). Both current and future
land use scenarios were evaluated. An ecological assessment was
also performed as a companion to the baseline human health risk
assessment. This section summarizes the findings of the risk
assessment. The complete risk assessment is presented in the RA
Report which is contained in the Administrative Record. The risk
assessment consisted of an identification of chemicals of
potential concern, an exposure assessment, a toxicity assessment,
and a risk characterization.
6.2
Contaminants of Concern
Contaminants of concern (COCs) are contaminants that have
been detected at the Shaw Avenue site that have inherent toxic or
carcinogenic effects and which are likely to pose the greatest
concern with respect to the protection of human health and the
environment. Forty individual compounds in addition to a group
of similar polycyclic aromatic hydrocarbons (PAHs) were
identified as potential chemicals of concern in the soil, surface
water, ground water, and chemical fill at the Shaw Avenue Dump
site. Toxicity information for all the. chemicals of concern was
evaluated including, where applicable, slope factors and criteria
for non-carcinogenic effects.
The potential compounds of concern detected within each
media of concern are listed in Tables 1-4. Sixteen of these
compounds as well as several of the PAHs are human carcinogens.
Exposures to potential chemicals of concern were identified
based on reasonable assumptions about current and future uses of
the Shaw Avenue Dump site. For current land use conditions,
exposures were evaluated for current residents living adjacent to
the Site and current workers at the site. In the evaluation of
future land use, scenarios involving residences built on the
Site, workers at the site and recreational uses were considered.
6.3
Toxicity Assessment
The toxicity assessment characterized available hu~anhealth
and environmental criteria for the contaminants of concern, and
qualitatively related potential chemical exposure (dose) to
expected adverse health effects (response)'. Included in this
assessment are the pertinent standards, criteria, advisories and
guidelines developed for the protection of human health and the
environment. An explanation of how these values were derived and
how they are applied is presented below.
Slope factors have been developed by EPA's Carcinogenic
Assessment Group for estimating excess lifetime cancer risks
associated with exposure to potentially carcinogenic chemicals.
Slope factors, which are expressed in units of (mg/kg-day)-~, are
multiplied by the estimated intake of a potential carcinogen, in
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mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate
of the risks calculated from the slope factor. Use of this
approach makes underestimation of the actual cancer risk highly
unlikely. Slope factors are derived from the results of human
epidemiological studies or chronic animal bioassays to which
animal-to-human extrapolation and uncertainty factors have been
applied. Slope factors for contaminants of concern at the site
are presented in Table 5.
Reference doses (RfDs) have been developed by EPA for
indicating the potential for adverse health effects from exposure
to chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg-day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals, that
are likely to be without an appreciable risk of adverse health
effects. Estimated intakes of chemicals from environmental media
(e.g., the amount of a chemical ingested from contaminated
drinking water) can be compared to the RfD. RfDs are derived
from human epidemiological studies or animal studies to which
uncertainty factors have been applied (e.g., to account for the
use of animal data to predict effects on humans). These
uncertainty factors help ensure that the RfDs will not
underestimate the potential for adverse noncarcinogenic effects
to occur. RfDs for contaminants of concern are presented in
Table 5.
6.4
Exposure Assessment
The exposure assessment identified potential pathways and
routes for contaminants of concern to reach the receptors and the
estimated contaminant concentration at the points of exposure.
Exposure pathways by which humans could be exposed to chemicals
of concern were identified based on reasonable assumptions about
current and future uses of the Site. Risks associated with
direct contact with surface soils were evaluated for both workers
and recreational users, since these represent both current and
future land uses. Residential use was also considered to be a
potential future land use. Possible routes of exposure include
ingestion, inhalation and dermal from surface water, ground
water, and soil.
Contaminant release mechanisms from environmental media,
based on relevant hydrologic and hydrogeologic information (fate
and transport, and other pertinent site-specific information,
such as local land or water use) were also presented. Potential
exposure pathways evaluated include ingestion of surface soils,
direct contact with surface soils, inhalation of dust', ingestion
of ground or surface water, inhalation of volatiles from surface
or ground water, and direct contact with surface or ground water.
Other routes include consumption of ,fish from the Cedar River or
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vegetables grown in contaminated soil. For each potentially
significant exposure pathway, exposure assumptions were made for
reasonable maximum exposures.
A reasonable maximum exposure (RME) represents a situation
which is more conservative than an average case but is not a
worst case scenario. As explained in guidance published by EPA
in October 1988 for conducting r~medial investigations and
feasibility studies, the RME scenario is developed to reflect the
types and extent of exposures that could occur based on the
likely or expected use of the Site in the future.
6.5
Risk Characterization
The risk characterization quantifies present and/or
potential future risks to human health that may r~sult from
exposure to the contaminants of concern found at the Site.
site-specific risk values were estimated by incorporating
information from the toxicity and exposure assessments.
When sufficient data is available, two quantitative
evaluations are made: the incremental risk to the individual
resulting from exposure to a carcinogen; or, for noncarcinogens,
a numerical index or ratio of the exposure dose level to an
acceptable reference dose. A description of the evaluation is
contained below.
The
6.5.1
Risks From Non-carcinogenic compounds
The EPA has developed standards, guidelines, and criteria
that provide levels of intakes considered to protect human
populations from possible adverse effects resulting from chemical
exposures. A ratio of the estimated chemical intake to the
Reference Dose (RfD) provides a numerical measure of the
potential that adverse health effects may result. This ratio is
referred to as the chronic hazard quotient (HQ). For
noncarcinogenic risks, the term "significant" is used when the
chronic HQ is greater than one. In the absence of federal
standards, the HQ is compared to the most applicable criteria or
guideline.'. .
Calculated chemical intakes, as describ~d previously, were
compared to chemical intakes associated with the most applicable
standard or guideline. The estimated chronic chemical intake, in
mg/kg-day, is estimated using the exposure assumptions and actual
site data. The chemical intake is then compared to the RfD .
(l.isted in Table 5 for contaminants of concern at this site) to
determine if chronic exposure to the contaminated medium presents
a risk. Because certain standards are derived for protection
against either subchronic or chronic exposures, chemical intakes
for noncarcinogens were developed for subchronic and chronic.
exposures and the associated risks were assessed as appropriate.
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Potential concern. for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the HQ (or the
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 media. .
In general, hazard indices greater than one are associated
with potentially increased health risk. The baseline risk
assessment indicated total hazard indices ranging from less than
one to 185. Indices were calculated for vinyl chloride, benzene,
1,1-dichloroethene, 1,2-dichloroethane, 1,1,2-trichloroethane,
arsenic, beryllium, cadmium, manganese, nickel, t~luene, and
xylene. A summary of the noncarcinogenic hazard indices are
presented in Table 6.
6.5.2
Risks From carcinogenic Compounds
For carcinogens or suspected carcinogens, a quantitative
risk assessment involves calculating risk levels considered to
represent the probability or range of probabilities of developing
additional incidences of cancer under the prescribed exposure
conditions. carcinogenic risk estimates, expressed as additional
incidences of cancer, are determined by multiplying the slope
factor by the projected exposure dose level. It is the slope
factor, expressed in (mg/kg/day)-' which converts the estimated
exposure dose level,. expressed in (mg/kg/~ay), to incremental
risk. These risks are probabilities that are generally expressed
in scientific notation (e.g., lX10-6). An excess lifetime cancer
risk of 1xlO-6 indicates that, as a plausible upper bound, an
individual has a one in one million chance of developing cancer
as a result of site-related exposure to a carcinogen over a
70-year lifetime under the specific exposure conditions at a
site. EPA has determined that remedial actions should minimize
the risk a~ the site so that it falls within a range of. 10-' to
10-6. The Agency considers this to be a generally acceptable
risk range.
The carcinogenic risk assessment for the site indicated that
under reasonable maximum exposure scenarios cancer risks for
future residential use range from 1xlO-3 to 6xlO-2 (one additional
person out of a thousand to six additional persons out of a
hundred are at risk of developing cancer). The risk assessment
also indicated a cancer risk of 3X10-3 from the chemical fill for
workers on the site. A summary of the results of calculations of
carcinogenic risks evaluated for the site are presented in
Table 6.
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6.5.3
Bnvironmental Evaluation
Environmental and ecological risks associated with the
presence of contamination at the Site were also evaluated as part
of the risk assessment and were determined to be minimal. The
ecological portion of the Risk Assessment determined that there
were no critical habitats or endangered species affected by
contamination present at the site. The impact on the Cedar River
was determined to be minimal. The arsenic concentration in the
Riv~r resulting from contamination at the site was estimated to .
be one part per million (ppm), which is below background and
below the concentration contributed by a nearby site which is
contributing a mean of twenty ppm to the River. There is
currently no use of the contaminated ground water.
6.5.4
Uncertainties
"
Regardless of the type of risk estimate developed, it should
be emphasized that all estimates of risk are based upon numerous
assumptions and uncertainties. In addition to limitations
associated with site-specific chemical data, other assumptions
and uncertainties that affect the accuracy of the site-specific
risk characterization result from the extrapolation of potential
adverse human effects from animal studies, the extrapolation of
effects observed at high dose to low dose effects, the modeling
of dose response effects, and route-to-route extrapolation.
The use of acceptable levels (established standards,
criteria, and guidelines) and unit cancer risks which are derived
from animal studies introduce uncertainty into the risk
estimates. In addition, the exposure parameters used in
estimating chemical intakes are often associated with
uncertainties. As such, these estimates should not stand alone
from the various assumptions and uncertainties upon which they
are based. In developing numerical indices of risk, an attempt
is made to evaluate the effect of the assumptions and limitations
on numerical estimates. When the assumptions and uncertainties
outweigh the meaningfulness of a risk assessment, a qualitative
as~essment of risk is performed. .
6.5.5
Conclusion
In conclusion, based on the results of the risk assessment,
EPA has determined that actual or threatened releases of
hazardous substances from this Site, if not remediated may
present an imminent or substantial endangerment to public health,
welfare, or the environment.
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7.0
Description of Alternatives
Chemical pill and contaminated 80il
7.1
The baseline risk assessment for the chemical fill and
contaminated soil at the Site indicated the potential for a
significant health threat to humans. The chemical fill and
contamination in the soil represents the principal threat at the
Shaw Avenue Dump site because it is the source of contamination
in the ground water. A full range of remedial alternatives for
contamination in soil and the chemical fill was evaluated in the
FS and Proposed Plan. Based on public comment EPA has decided to
divide the remedy for this Site into two operable units.
Operable unit one will address the chemical fill and surrounding
contaminated soil. Operable unit two will address contaminated
ground water. The selected remedy for the first operable unit is
presented in this ROD. The remedy involving the ~econd operable
unit will be presented in a future ROD. However, for
informational purposes the ground water alternatives presented in
the Proposed Plan are described in Section 7.2 of this ROD. .
7.1.1
No Action
The National Contingency Plan requires that the "no action"
alternative be evaluated for every site. This alternative
provides a baseline for comparing the effectiveness of the other
remedial alternatives. Under this option, no further action
would be taken at the site to prevent exposure to contaminated
soils or migration of contamination from the site. The Site
would remain in its present condition. There would be no costs
associated with this alternative. This alternative would not
comply with ARARs and would not be protective of human health and
the environment. .
Deed Restrictions, Access Control, capping, and
Monitoring
This alternative would include removal of the underground
gasoline tank, installation of a Resource Conservation and
. Recovery Act (RCRA) cap over the chemical fill, implementation of
deed restrictions, installation of a fence and markers around the
chemical fill, and ground water monitoring. The RCRA cap would
consist of (from bottom to top) a 2-foot compacted clay layer, a
high-density polyethylene (HDPE) liner, a I-foot drainage layer,
a 2-foot fill layer, 6 inches of topsoil, and a vegetative cover.
The RCRA cap would minimize infiltration of surface water through
the fill, thereby, minimizing contaminant migration out of the
chemical fill. Restrictions would be placed on the property deed
to inform any future property owners of the presence of the
chemical fill, limit future use of the Site, prevent the
potential use of the ground water beneath the Site, and protect
the integrity of the cap. A security fence and warning markers
7.1.2
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would be installed outside the boundaries of the cap covering the
fill to prevent unauthorized site entry. Ground water quality
monitoring would be conducted to assess the effectiveness of the
cap in preventing migration of the contaminants. This
alternative would require long-term maintenance and monitoring.
site inspections would be required on a regular basis along with
maintenance of the cap, including necessary repairs. Sampling of
existing monitoring wells would be conducted to monitor ground
water quality.
Institutional controls at the site under this alternative
would consist of deed restrictions placed on the landfill
property. This would require the city of Charles city, the
owners of the Site, to submit for recording by the Recorder of
Deeds, Floyd county, state of Iowa a restrictive covenant which
would run with the property comprising the Site an~ which would
prohibit the construction, installation, maintenance, or use of
any wells on the site for the purposes of extracting water for
human drinking, bathing, or swimming purposes or for the
irrigation of food or feed crops as well as any construction or
intrusive activities at the Site. The city would also submit for
recording with the Recorder of Deeds, access easements, which
would run with the property comprising the site and which reserve
such access as may be necessary for the city and Solvay to
implement the remedial action and for conducting .O&M. The city
would also provide access to EPA to oversee these activities.
This alternative would not reduce the toxicity, mobility or
volume of the chemical fill contaminants through treatment.
Five-year reviews would be required to assess the effectiveness
of the alternative because the contaminants would be left onsite.
No chemical or location-specific ARARshave been identified
for this alternative. Major action-specific ARARs for this
alternative include RCRA closure requirements (40 CFR Part 264),
the underground storage tank regulations (40 CFR Part 280,
subpart G), OSHA, and the Iowa Rules for Determining Cleanup
Actions and Responsible Parties (I.A.C., Chapter 567-133). This
alternative would meet these ARARs.
Implementation of this alternative would. take less than six
months. The estimated capital cost and the present worth of the
O&M costs, based on a 5 percent discount rate over a 30-year
period, are $79,700 and $65,550, respectively, meaning the total
estimated present worth cost for this alternative is $145,250.
7.1.3
Chemical Fill Excavation and Offsite Disposal
This alternative would consist of excavation and removal of
the underground gasoline tank and excavation and disposal of the
chemical fill material and contaminated subsurface soil. The
excavated material would be disposed of at an offsite RCRA
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permitted disposal facility. The excavated area would then be
backfilled with clean material.
This alternative would not reduce the toxicity, mobility, or
volume of the contaminants because no treatment technology would
be used. No chemical or location-specific ARARs have been
identified for this alternative. Major action-specific ARARs for
this alternative include the RCRA requirements located in 40 CFR
Part 264, the underground storage tank regulations (40 CFR Part
280, Subpart G), OSHA, and the Iowa Rules for Determining Cleanup
Actions and Responsible Parties (I.A.C., Chapter 567-133). All
Department of Transportation regulations applicable to
transportation of hazardous waste would have to be observed.
This alternative would also have to meet RCRA Land Disposal
Restrictions (40 C.F.R. Part 268) which require treatment of the
hazardous waste prior to disposal in a RCRA-authorized hazardous
waste landfill. The type of treatment would be dictated by
requirements of the RCRA Land Disposal Restrictions. Under
current regulations this material does not require treatment
prior to disposal. However, in May of 1992 the Land Disposal.
Restrictions will require treatment prior to disposal of these
materials. .
Implementation of this alternative would take less than six
months. No O&H costs would be associated with this chemical fill
alternative because there would be no O&H for the soils.
However, a five-year review and therefore, ground water
monitoring would be required because of ground water
contamination. The estimated capital costs and present worth of
this alternative is $845,000.
7.1.4
Deed Restrictions, Access Control, In situ
Fixation/stabilization, Capping, and Monitoring
This alternative would include in situ fixation/
stabilization of the chemical fill, construction of a low-
permeability cap over the fixated/stabilized fill, implementation
of deed restrictions, installation of a fence and markers around
the capped fill, and monitoring of the ground water quality. In
addition, the underground gasoline tank would be removed and
disposed of.
In situ fixation/stabilization would be accomplished through
the addition of a reagent (a cement-like material) to the wastes
that mechanically locks the contaminants within the solidified
matrix. The type and application rate of the reagent would be
determined by a laboratory bench-scale study. The in situ
fixation/stabilization would consist of mixing the reagent
(generally in the form of a slurry) directly with the. chemical
fill and contaminated soil in situ. One method of mixing the
materials which is appropriate for wastes that extend deeper than
three to four feet involves adding the reagent to the waste in
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1-foot increments. Upon fixation/stabilization of the 1-foot
layer, the fixated material would be scraped to the side within
the excavation and the process repeated on the next layer. When
the last layer has been fixated/stabilized, all the treated
material would be recompacted in the excavation.
Following fixation/stabilization, the soil mass would be
covered to prevent human contact and to protect the
fixated/stabilized mass. A low-permeability cap consisting of
either a 2-foot clay layer covered by a 2-foot fill and vegetated
layers or an 8-inch thick reinforced concrete slab would be
placed over the waste. FOllowing construction of the soil cap,
vegetation would be established to prevent erosion. The best
fixation/stabilization method would be determined during the
laboratory bench-scale study.
Institutional controls at the site under this alternative
would consist of deed restrictions placed on the landfill
property. This would require the City of Charles City, the
owners of the Site, to submit for recording by the Recorder of
Deeds, Floyd County, State of Iowa a restrictive covenant which
would run with the property comprising the Site and which would
prohibit the construction, installation, maintenance, or use of
any wells on the site for the purposes of extracting water for
human drinking, bathing, or swimming purposes or for the
irrigation of food or feed crops as well as any construction or
intrusive activities at the Site. The City would also submit for
recording with the Recorder of Deeds, access easements, which
would run with the property comprising the site and which reserve
such access as may be necessary for the City and Solvay to
implement the remedial action and for conducting O&M. The City
shall also provide access for EPA to oversee these activities. A
security fence and warning markers would be installed outside the
boundaries of the capped and fixated/stabilized fill to prevent
unauthorized Site entry.
Ground water quality monitoring would be conducted to assess
the effectiveness of the fixation/stabilization in preventing
migration pf the .contaminants.
This alternative would reduce the mobility of the chemical
fill contaminants through treatment. However, the toxicity would
not be reduced and the volume would actually increase as a result
of the addition of the reagent. No chemical- or location- .
specific ARARs have been identified for this alternative. Major
action-specific ARARs for .this alternative are the underground
storage tank regulations (40 CFR Part 280, Subpart G), OSHA, and
the Iowa Rules for Determining Cleanup Actions and Responsible
Parties (I.A.C., Chapter 567-133). This alternative would meet
these ARARs. This alternative would require long-term
maintenance and monitoring. Site inspections would be.required
pn a regular basis along with maintenance of the cap. Sampling
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of existing monitoring wells would be conducted to monitor ground
water quality. '
Implementation of this alternative would take ,less than
twelve months. The estimated capital costs and the present worth
of the O&M costs, based on a 5 percent discount rate over a
30-year period, are $447,850 and $65,550, respectively, making
the total estimated present worth cost for this alternative is
$513,400.
Because this alternative would result in contamination
remaining on the site, CERCLA requires that the Site would be
reviewed every five years.
7.2
Ground Water
The baseline risk assessment for the ground water at the
Site indicated the potential for a significant health threat to
humans. Therefore, a full range of remedial alternatives for
contamination in the ground water was evaluated. These
alternatives would have to meet all ARARs. The alternatives are
described below. As noted above, after consideration of the
public comments submitted in this matter, EPA has decided to '
separate the remedy for this site into two operable units. The
EPA preferred alternative for the operable unit involving ground
water contamination will be presented in a Proposed Plan at some
time in the future. The public will be given the opportunity to
comment on the Proposed Plan. Although the ground water
alternatives will not be implemented, they are reviewed briefly
here. These alternatives are discussed in detail in the FS which
is part of the Administrative Record for this site.
7.2.1
No Action
The NCP requires that the no action alternative be evaluated
for every site to provide a baseline for comparison to the other
alternatives. Under the no action alternative, no action would
be taken to prevent or reduce ground water contamination.
, '
Ground water samples would be collected from existing onsite
monitoring wells and analyzed for volatile organics and total
metals. Sampling would be conducted on a quarterly basis during
the first five years and would be subsequently conducted
annually.
Because this remedy would result in hazardous substances
'remaining onsite above health-based levels, a review would be
conducted within five years after commencement of the remedial
action to ensure that the remedy continues to provide adequate
protection of human health and the environment.
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Costs for the no action alternative would include costs for
the collection and analysis of ground water samples for ten
years. The total present worth of the no action alternative is
estimated to be $34,000.
7.2.2
Ground Water xonitoring
Under this alternative, ground water quality samples would
be collected from existing onsite monitoring wells and analyzed.
The. samples would be collected and analyzed on an annual,
semiannual, quarterly, or monthly basis from monitoring wells,
depending on well location and parameter of concern as proposed
in Table 7. This is different than the ground water sampling
under the no-action alternative which is simply the monitoring
required to conduct a five year review. Because ~he contaminants
would remain onsite, five-year reviews would also be required for
this alternative.
Institutional controls at the site under this alternative
would be identical to those required for the chemical fill and
contaminated soil alternatives.
Because this remedy would result in hazardous substances
remaining onsite above health-based levels, a review would be
conducted within five years after commencement of the remedial
action to ensure that the remedy is providing adequate protection
of human health and the environment. .
Chemical-specific ARARs applicable to this alternative
include the federal Maximum Contaminant Levels (MCLs) and Maximum
Contaminant Level Goals (MCLGs) and Iowa Rules for Determining
Cleanup Actions and Responsible Parties (I.A.C., Chapter 567-
133). These ARARs would have to be met before the Site could be
deleted from the NPL.
Costs for this alternative would include the Operation and
Maintenance (O&M) costs for the collection and analysis of ground
water samples and the five-year reviews. . The total present worth
of,this alternative, based ona five percent discount rate .over
30 years, is estimated to be $65,550.
7.2.3
Ground Water Extraction and ~reatment at the PUblicly
Owned Treatment Works (POR)
This alternative would involve extraction of ground water
from beneath and down gradient from.the Shaw Avenue Dump Site to
hydraulically contain the contaminant plume thereby preventing
further migration of contaminants toward the Cedar River. Four
bedrock extraction wells would be installed to remove ground
water at a total extraction rate of 80 gallons per minute (gpm)
or 115,200 gallons per day. Approximately 42 million gallons of
ground water would be extracted each year. The extracted ground
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water would be pumped through a new force main to the Charles
City POTW for treatment.
The POTW is designed to treat a wastewater flow of
2.44 million gallons per day (MGD), but is able to handle a
maximum flow of 6.1 MGD. Treatment of wastewater at the POTW
consists of the following operations: screening, flow monitoring
and grit removal, settling in two primary clarifiers, biological
degradation of organic compounds in a single-stage trickling
filter, settling in a secondary clarifier, wastewater sampling at
two sampling stations, and discharge of treated effluent to an
outfall on the Cedar River. Sludge from the primary and
secondary clarifiers would be further treated in two aerobic
digesters. The trickling filter would be the primary means of
treating ground water extracted from the Shaw Avenue Dump Site.
It is not anticipated that the metals, specifically arsenic and
magnesium, present in the ground water would be tr.eated by the
POTW.
This alternative would also involve establishing a
hydraulic monitoring system, a ground water quality monitoring
system, and a ground water extraction monitoring system at the
Site. Hydraulic monitoring would involve the collection of water
levels on a quarterly basis to plot ground water contours in
order to define ground water flow patterns. The hydraulic
monitoring would demonstrate the hydraulic containment provided
by the ground water extraction system. Ground water quality
monitoring would include the collection of ground water samples
on an annual, semiannual, quarterly, or monthly basis from
monitoring wells, depending on well location and parameter of
concern. The goal of the ground water quality monitoring would
be to assess the effectiveness of 'source.control remediation, to
monitor the progress of ground water remediation, and to
determine the redistribution of contamination in response to the
pumping of ground water. Ground water extraction monitoring
would include collection and analysis of samples from extraction
wells and the combined well influent to the POTW to assess
treatment efficiency and to monitor the progress of ground water
. remediation.
Institutional controls at the site under this alternative
would be identical to those required for the chemical fill and
contaminated soil alternatives.
This alternative would take twelve months to be operational.
It is anticipated that the restoration of bedrock ground water
would take more than 30 years. The capital cost of this
alternative is estimated to be $168,100. The O&M costs are
anticipated to be $53,000 each year. The total present worth of
this alternative, assuming a 30-year remedial action, is
estimated to be $990,800. .
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Because this remedy would result in hazardous substances
remaining on-site above health-based levels, a review would be
conducted within five years after commencement of the remedial
action to ensure that the remedy is providing adequate protection
of human health and the environment. These five-year reviews'
would also be used to assess the progress of ground water
remediation.
The primary federal and state ARARs for this ground water
alternative are chemical or action-specific regulations. The
MCLs and MCLGs specified by the Safe Drinking Water Act (SDWA)
are relevant and appropriate for remediation of ground water at
the Site. Iowa Water Quality (I.A.C., Chapter 567-133) standards
are applicable to contaminant levels present in the Cedar River
from the recharge of contaminated ground water from the Site.
The General Pretreatment Regulations for Existing ~nd New Sources
of Pollution [40 Code of Federal Regulations (CFRj 403.5] would
be applicable to the discharge of ground water to the POTW.
Discharge of treated effluent from the POTW would have to
continue to comply with the City's National Pollutant Discharge
Elimination System (NPDES) permit after, discharge of ground water
to the wastewater treatment plant began. The Occupational Safety
and Health Act (OSHA) would be applicable during construction and
operation of this alternative. This alternative would satisfy
all ARARs, but does not satisfy the CERCLA preference for
treatment. Pretreatment of the ground water for arsenic and
manganese before discharging it to the POTW is 'necessary, because
according to the EPA guidance IICERCLA site Discharges to POTWs",
a contaminant passes through the POTW untreated if a POTW does
not specifically treat for that particular contaminant.
Pretreatment is required even if the discharge limits (in this
case, the limits stated in the POTW's NPDES permit) for this
contaminant are not exceeded.
7.2.4
Ground Water Extraction, Pretreatment by Chemical
precipitation, and Treatment at the POTW
This ground water alternative would be identical ,to the
ground water alternative described in Section 7.1.3 with the
exception that the ground water would be pretreated before being
discharged to the POTW. Chemical precipitation would be used to
remove arsenic and manganese from the ground water prior to being
discharged to the POTW. In this process, flocculent agents would
be added to the ground water to aid in the formation of floc that
are large enough to settle out of the ground water. An iron
coprecipitation process would be used to treat the ground water
because it has a greater removal efficiency that conventional
alkaline precipitation. During this process, heavy metals are
trapped in an insoluble iron matrix. Entrapment occurs when the
heavy metals that are coprecipitated with iron are rapidly
removed from the ground water. The ground water would be '
clarified before being discharged to the POTW. System components
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would include an equalization tank, a reactor module, a
clarification and flocculation module, a sludge dewatering
system, a polymer blending and addition system, and a bulk
chemical handling, storage, and addition system. The process
would produce approximately 19.6 pounds of sludge per day, or
3.6 tons per year, and may require disposal at a hazardous waste
facility.
This alternative would take no longer than twelve months to
be operational. It is anticipated that the restoration of
bedrock ground water to a usable state would take more than
30 years. The capital cost of this alternative is estimated to
be $294,100. The present worth of the O&M costs are anticipated
to be $68,840 annually. The total'present worth of this
alternative, assuming a 30-year remedial action, is estimated to
be $1,352,400. -
.-
Because this remedy would result in hazardous substances
remaining onsite above health-based levels, a review would be
conducted within five years after commencement of the remedial
action to ensure that t~e remedy is providing adequate protection
of human health and the environment. These five-year reviews
would also be used to assess the progress of ground water
remediation.
The primary federal and state ARARs for this ground water
alternative are chemical or action-specific regulations. The
MCLs and MCLGs specified by the SDWA are relevant and appropriate
for remediation of ground water at the site. Iowa Water Quality
standards (I.A.C., Chapter 567-133) are applicable to contaminant
levels present in the Cedar River from the recharge of
contaminated ground water from the site. The General
Pretreatment Regulations for Existing and New Sources of
Pollution (40 CFR 403.5) would be applicable to the discharge of
ground water to the POTW. Discharge of treated effluent from the
POTW would have to continue to comply with the NPDES permit
currently held by the city's POTW after discharge of ground water
to the wastewater treatment plant began. OSHA rules and
regulations would be applicable during construction and.operation
of this alternative. .
8.0
Summary of comparative Analysis of Alternatives
Nine evaluation criteria have been developed by EPA to
address CERCLA statutory requirements and technical, cost, and
institutional considerations which the Agency has determined
appropriate. The evaluation criteria serve as the basis for
conducting detailed analysis during the FS and for subsequently
selecting an appropriate remedial action~ Attachment A provides
a glossary of the evaluation criteria. This comparison will be
conducted only for the chemical fill and contaminated soil
alternatives since this ROD addresses that operable unit.
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The preferred alternative for the cleanup of contaminated
soils and chemical fill at the Shaw Avenue Dump Site is in situ
fixation/stabilization and capping. Based on current
informati~n, this alternative appears to provide the best balance
among the alternatives with respect to the evaluation criteria.
The preferred alternative is described below in relation to the
evaluation criteria and is compared to the other alternatives
under each criterion.
8.1.1
overall protection of Human Health and Bnvironment
The in situ fixation/stabilization alternative would be
protective of human health and the environment. Fixation/
stabilization and capping of the contaminated soils and chemical
fill would reduce direct contact exposure to protective levels
and also minimize the potential for contaminant m~ration.
Ground water monitoring would be conducted to assess the
performance of this alternative in preventing contaminant
migration.
with the exception of the no action alternative, all the
other alternatives provide protection to human health and the
environment by removing, reducing, or controlling risk through
treatment, engineering controls, or institutional controls.
8.1.2
compliance with ARARs
The fixation/stabilization alternative will comply with all
federal and state ARARs, including the Iowa Responsible Parties
Cleanup Regulations (I.A.C., Chapter 567-133) and OSHA.
All the other alternatives except for the no action
alternative would comply with all identified ARARs.
8.1.3
Long-Term Effectiveness and Permanence
Implementation of the in situ fixation/stabilization and
capping alternatives would effectively reduce the long-term risks
associated with direct contact with the contaminated soil and
chemical fill and potential contaminant migration at the Shaw
Avenue Dump site. Long-term controls would be required to ensure
the integrity of the remedy. All of the soil/chemical fill
alternatives, except no action, would be effective in reducing
the long-term risks associated with direct contact with the.
contaminated soil and chemical fill and potential contaminant
migration.
8.1.4
Reduction of Toxicity, Hobility, or volume Through
Treatment
Only the in situ fixation/stabilization alternative would
.employ treatment to reduce the mObility of the contaminants.
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However, in situ fixation/stabilization would actually increase
the volume of contaminated material. None of the alternatives
would reduce the toxicity or volume of the contaminants in the
chemical fill. In May of.1992, Land Disposal Restrictions will
require treatment prior to disposal of these materials.
Therefore, if the materials are excavated and removed pursuant to
Alternative 7.1.3 after May of 1992, treatment would be required.
8.1.5
Short-Term Effectiveness
The short-term risks associated with the in situ
fixation/stabilization alternative include worker exposure to
contaminants and possible exposure of the public and workers at
the site to fugitive dust and surface runoff. These potential
exposures can be effectively minimized and contr~lled by
compliance with the action-specific ARARs and the implementation
of engineering controls such as dust suppressants.-and berms.
All the other soil/chemical fill alternatives (except the
no-action alternative) would present the same short-term risks
identified above in relation to onsite construction, excavation,
and loading. .
8.1.6
Implementability
Implementation of the in situ fixation/stabilization
alternative would involve conventional techniques that are
readily available, proven, and reliable. Bench scale
treatability tests would be performed to determine the type and
application rate of the fixation/stabilization reagent to be
used. There are no anticipated significant administrative
issues, such as permitting, that would affect the
implementability of this alternative.
Implementation of the other alternatives would also involve
conventional technologies that would not present any technical or
administrative impediments.
8.1."
~ost
The present worth of the soil/chemical fill alternative is
approximately $513,400. The estimated present worth of the no-
action alternative is $34,800. The present worth of the capping
alternative is $145,250. The estimated present worth of the
removal alternative is approximately $845,000.
8.1.8
State Acceptance
The state of Iowa supports the preferred alternative for the
cleanup of contaminated soils and chemical fill at the Shaw
Avenue Dump Site.
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8.1.9
community Acceptance
Community acceptance of the soil and chemical fill
alternative of in situ fixation/stabilization has been evaluated
following the Public Meeting held on July 24, 1991, and
conclusion of the public comment period on August 12, 1991. The
results of this evaluation are presented in the attached
Responsiveness Summary.
8.2.
Ground Water Alternatives
After consideration of the public comments, EPA has decided
to separate the remedy for this Site into two operable units.
Operable unit one will address the chemical fill and surrounding
contaminated soil. Operable unit two will address the
contaminated ground water. The remedy for operable unit one is
presented in this ROD and the selected remedy for operable unit
two will be presented in a Proposed Plan to be issued at some
time in the future. The public will be given an opportunity to
comment on the Proposed Plan. Since this ROD addresses the
remedy for the chemical fill and contaminated soil the
comparative analysis of the ground water alternatives is not
presented here. This comparison is presented in detail in the FS
and the Proposed Plan which is part of the Administrative Record
for this site.
9.0
Selected Remedy
Based on the Risk Assessment for the Site, EPA has
determined that elevated levels of contaminants including arsenic
exist at the Site above levels of concern for human health and
the environment.
On the basis of an evaluation of the relative performance of
each alternative utilizing the evaluation criteria contained in
the NCP, the EPA has determined that the in situ fixation/
stabilization and capping alternative presents the best balance
among the alternatives for remediation of the contaminated soils
and chemical fill. This selected alternative will satisfy the
statutory requirements in CERCLA section 121, which states that
the remedy should be protective of human health and the
environment, be cost-effective, and utilize permanent solutions
and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable. However, the
full effectiveness of the technology employed by the selected
remedy cannot be determined until treatability studies are
performed during the design phase. If it is determined through
treatability testing that the technology will not be adequate,
al.ternative 7.1.3 (Excavation and Offsite Removal) will be
implemented. Alternative 7.1.3 complies with all the statutory
requirements with the exception that under current regulations it
would not require treatment. However, in May of 1992 the Land
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Disposal Restrictions will require treatment prior to disposal .of
these materials. The fixation/stabilization remedy is the only
remedy considered for operable unit one that utilizes treatment.
A decision to change the remedy from fixation/stabilization to
alternative 7.1.3 would be accomplished in an Explanation of
significant Differences which would be published in a local
newspaper of general circulation.
This alternative will include in situ fixation/stabilization
of the chemical fill, construction of a low-permeability cap over
the fixated/stabilized fill, implementation of deed restrictions,
installation of a fence and markers around the capped fill, and
monitoring of the ground water quality. In addition, the
underground gasoline tank would be removed and disposed of.
This alternative will fixate/stabilize all of the soils and
chemical fill contaminated above health-based leve~s in the area
of the three waste cells identified near the city's maintenance
building. This will prevent and/or minimize hazardous waste
leaching into the ground water, thereby reducing the potential
for contaminant migration. Also, any contaminated surface soils
. will be fixated/stabilized at the same time.
The selected alternative will not pose any unacceptable
short-term impacts to human health and the environment during its
implementation.
In situ fixation/stabilization is accomplished through the
addition of a reagent (a cement like material) to the wastes that
mechanically locks the contaminants within the solidified matrix.
Before implementation of this remedial alternative, a laboratory
bench-scale study will be performed to determine the type and
application rate of the fixation/stabilization reagent to be
used. If the laboratory bench scale test indicates that
fixation/stabilization is not effective on the wastes at the Shaw
Avenue Dump Site, the contaminated chemical fill and soil will be
excavated and disposed of at an offsite, RCRA permitted disposal
facility. The best fixation/stabilization method will be
.. dete~ined during the laboratory bench-scale study. One method
of mixing the materials which is appropriate for wastes that
extend deeper than three to four feet involves adding the reagent
to the waste in l-foot increments. Upon fixation/stabilization
of the I-foot layer, the fixated material is scraped to the side
within the excavation and the process is repeated on the next
layer. When the last layer has been fixated/stabilized, all the
treated material is recompacted in the excavation.
Following fixation/stabilization the soil mass will be
covered to prevent direct contact and to protect the solidified
mass. A low-permeability cap consisting of either a 2-foot clay
layer covered by a 2-foot fill and vegetated layers or an 8-inch
thick reinforced concrete slab would be placed over the waste.
-------
26
Following construction of the soil cap, vegetation would be
established to prevent erosion.
Institutional controls at the site for the selected
alternative would consist of deed restrictions placed on the
landfill property. This would require the City of Charles City,
the owners of the Site, to submit for recording by the Recorder
of Deeds, Floyd county, State of Iowa, a restrictive covenant
which would run with the property comprising the Site and which
would prohibit the construction, installation, maintenance, or
use of any wells on the Site for the purposes of extracting water
for human drinking, bathing, or swimming purposes or for the
irrigation of food or feed crops as well as any construction or
intrusive activities at the Site. The City would also submit for
recording with the Recorder of Deeds, access easements, which
would run with the property comprising the site and which reserve
such access as may be necessary for the City and.Solvay to
implement the remedial action and for conducting O&M. The City
shall also provide access for EPA to oversee these activities. A
security fence and warning markers will be installed outside the
boundaries of the capped and fixated/st~bilized fill to prevent
unauthorized Site entry.
The selected alternative will satisfy all federal and state
ARARs. It will comply with I.A.C. Chapter 567-133 which requires
remedial actions in the State of Iowa to address soil
contamination which may adversely affect ground water, OSHA, and
with the underground storage tank regulations (40 CFR Part 280,
Subpart G). There are no chemical-specific or location-specific
ARARs for the contaminants in the soil and the chemical fill.
The selected alternative will also utilize permanent solutions
and treatment technologies to the maximum extent practicable.
The determination of the maximum extent to which permanent
solutions and treatment can be practically used takes into
consideration a number of factors including long-term and short-
term effectiveness of the alternative, implementability, and
cost.
Groun4 water quality monitoring will be conducted ~o assess
the effectiveness of the fixation/stabilization in preventing
migration of the contaminants. Sampling of existing monitoring
wells will be conducted to monitor ground water quality. The
selected alternative would reduce the mobility of the chemical
fill contaminants through treatment. However, the toxicity would
not be reduced and the volume would actually increase from the
addition of the reagent. Because the contaminants will be left
onsite, five-year reviews will be required by CERCLA to assess
the effectiveness of the alternative in protecting human health
and the environment. This alternative will require long-term
maintenance and monitoring. Site inspections will be required on
a regular basis along with maintenance of the cap.
-------
27
Implementation of this alternative will take less than
twelve months. The estimated capital costs and the present
of the O&M costs, based on a 5 percent discount rate over a
30-year period, are $447,850 and $65,550, respectively. The
total estimated present worth cost for this alternative is
$513,400. See Table 9 for details.
worth
Concentrations of contaminants in soil which would be
protective of human health and the environment were determined in
the baseline risk assessment for several contaminants of concern
at the Shaw Avenue Dump Site. The protective concentrations are
based on the conservative residential exposure scenarios for both
an average and maximum case. The protective soil concentrations
were determined to represent a reasonable maximum exposure. For
arsenic and cadmium, soil cleanup levels are 50 parts per million
(ppm) and 20 ppm, respectively. Therefore, all soil or chemical
fill containing arsenic or cadmium above these levels will be
fixated/stabilized to where they do not fail the Toxic
Characteristic Leachate Procedure (TCLP). .
10.0
statutory Det~rminations
Under its legal authority, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that achieve
adequate protection of human health and the environment. In
addition, Section 121 of CERCLA establishes several other
statutory requirements and preferences. These specify that when
complete, the selected remedial action for this site must comply
with applicable or relevant and appropriate environmental
standards established under federal and state environmental laws,
unless a statutory waiver is justified. The selected remedy also
must be cost effective and utilize permanent solutions and
alternative treatment technologies or resource recovery
technologies to the maximum extent practicable. Finally, the
statute includes a preference for remedies that employ treatment
that permanently and significantly reduce the volume, toxicity,
or mobility of hazardous wastes as their principal element. The
following sections discuss how the selected remedy meets these
statutory requirements.
10.1
Protection of Human Health and the Bnvironment
The selected remedy protects human health and the
environment through containment and treatment of the contaminants
by fixation/stabilization of the contaminated soil and chemical
fill into a solid matrix that will bind and/or entrap the
contaminants thereby immobilizing them and preventing future
releases.
Fixation/stabilization will also eliminate any threat posed
by direct contact with the chemical fill or contaminated soil .as
well as threats posed to any future residential users of the site
-------
28
or adjacent land areas. By preventing direct contact with the
contaminants, and immobilizing the contaminants, the Hazard
Indices (HI) and the Site related cancer risks would be reduced.
There are no short-term threats associated with the selected
remedies that cannot be readily controlled. In addition, the
remedy is not anticipated to result in any adverse cross-media
impacts.
The contingency remedy would also be protective of human
health and the environment and eliminate any direct contact
threats from the chemical fill and contaminated soil. There
would be no short term threats associated with the contingency
remedy.
10.2
Compliance with Applicable or Relevant and Appropriate
Requirements
,-
Both the selected remedy and the contingency remedy will
comply with all identified federal and state ARARS. There are no
identified chemical-specific or location-specific ARARS.
Both alternatives for the chemical fill
soil comply with I.A.C Chapter 567-133 which
actions in the State of Iowa to address soil
may adversely affect ground water.
and contaminated
requires remedial
contamination that
10.3
Cost-Effectiveness
The selected remedy is cost effective because it has been
determined to provide overall effectiveness proportional to its
cost. The net present value of the remedy is approximately
$513,000. The selected remedy is the least costly of remedies
that were deemed to be equally protective of human health and the
environment. The contingency remedy is the second most cost
effective remedy that provides protection to human health and the
environment equal to fixation/stabilization.
10.4
utilization of Permanent Solutions and Alternative
Treatment (or resource recovery) Technologies to
the xaximum Bxtent Practicable
The EPA has determined that permanent solutions and
treatment technologies are utilized in a cost-effective manner
for the Shaw Avenue Dump site by the selected remedy to the
maximum extent possible. Further, of the alternatives that are
protective of human health. and the environment and comply with
ARARs, the EPA and the State of Iowa have determined that the
selected remedy provides the best balance in terms of long-term
effectiveness and permanence, reduction in toxicity, mobility or
volume achieved through treatment, short-term effectiv~ness,
implementability, and cost. The EPA also factored in the
-------
29
statutory preference for treatment and considered input from the
community in balancing the remedial alternatives.
The chemical fill/contaminated soil alternatives involving
institutional controls with capping and excavation/offsite
disposal do not satisfy the CERCLA preference for treatment. In
terms of long-term effectiveness the institutional controls with
capping and excavation/offsite disposal alternatives provide
equal protection to human health and the environment. Therefore
the selected remedy was determined to be the most appropriate
solution for the contamination at the Shaw Avenue Dump site.
Under current regulations the contingency remedy would not
require treatment to reduce toxicity, mobility, or volume.
However, in May of 1992 the Land Disposal Restrictions will
require treatment prior to disposal of these materials.
.-
10.5
Preference for Treatment as a principal Element
The selected remedy addresses the principal threat of the
chemical fill and contaminated soil by fixation/stabilization.
Therefore, the statutory preference for remedies that employ
treatment as a principal element is satisfied. The contingency
remedy would not currently satisfy the preference for treatment.
However, in May of 1992, the Land Disposal Restrictions will
require treatment prior to disposal of these materials pursuant
to Alternative 7.1.3.
11.0
Documentation of Significant changes
The Proposed Plan for the Shaw Avenue Dump Site was released
for public comment on July 12, 1990. It identified EPA's
preferred remedial alternatives to be extraction, pretreatment
and discharge to and treatment by the POTW for the ground water
and fixation/stabilization of chemical fill and surrounding
contaminated soil and capping the Site. The EPA reviewed all
comments received during the public comment period and after
consigeration of these comments decided to implement the remedy
at the Site through two operable units. The first operable unit
will address the chemical fill and surrounding contaminated soil
and the second operable unit will address the contaminated ground
water.
EPA has selected the fixation/stabilization alternative as
the remedy for operable unit one. EPA has decided, after
consideration of the public comments, that at some point in the
future it will issue another Proposed Plan that will contain
EPA's preferred alternative for operable unit two. At that time,
the pUblic will be given the opportunity' to comment on EPA's
preferred alterative as well as the other alternatives considered
by EPA.
-------
30
ATTACBKENT A
GLO~SARY OF EVALUATION CRITERIA
The following criteria were developed by EPA to address
CERCLA statutory requirements and technical, cost, and
institutional considerations. The evaluation criteria serve as
the basis for conducting detailed analyses during the FS and for
subsequently selecting an appropriate remedial action.
OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
Alternatives are assessed to determine if they can provide
adequate protection from risks above health-based levels posed by
contamination present at the Shaw Avenue Dump site by
eliminating, reducing, or controlling exposures. -
COMPLIANCE WITH ARARs
.-
The alternatives are assessed to determine if they attain
applicable or relevant and appropriate requirements (ARARs) or
comply with other federal and state environmental and public
health laws, or provide grounds for invoking a waiver.
LONG-TERM EFFECTIVENESS AND PERMANENCE
The magnitude of risk remaining after implementation of the
alternatives is evaluated. The adequacy and reliability of
controls used to manage treatment residuals or untreated wastes
that remain at the Shaw Avenue Dump Site are also assessed.,
REDUCTION OF TOXICITY, MOBILITY, AND VOLUME THROUGH
TREATMENT
The degree to which the alternatives employ treatment that
reduces toxicity, mobility, or volume through treatment is
assessed.
SHORT-TERM EFFECTIVENESS
The alternatives are evaluated regarding their effects on
human health and the environment during implementation of the
alternative. The amount of time until protectiveness is achieved
is also an assessment factor.
IMPLEMENTABILITY
The technical and administrative feasibility of implementing
an alternative and the availability of services and materials
required to implement an alternative are evaluated.
-------
31
COST
Direct and indirect capital costs and operation and
maintenance costs incurred over the life of the project are
identified.
STATE ACCEPTANCE
Technical and administrative issues and concerns the state
may have regarding the alternative are assessed.
COMMUNITY ACCEPTANCE
The issues and concerns of the public regarding the
alternatives are assessed.
.-
-------
&'1''1'AC'EKD': .
~%Gt7U8
. ,
L-
.'
-
-------
~
.
.
CIT~
..
~tFE~r:N:E: SHAW AVE NIJ!:-SIT£ . RI/ n, JUNE tit! .
FIGURE I
SITE LOCATION
SI'l~W AV£~U£ SIT£
'~O~SEO '~&N
-------
. .
fi1"
. . -
-
. .
.,
LEGEND.
---
A~ftnO'CIMATt
SIT[ ROUftOAR"I
!JounC[: [OO£H[ A. "lCkOIC AND ASSoe'aTtS fttPO'tT ..,1.,
FIGURE 2
I\PPR01CIMATE SITE bOONOARY
SH". "VENUE SITE
PRoPOSED Pt.AN
-------
- .. - ...
.
.
I
I'
.
.
.
) ;.,. j i1
. -..
"~
.,
.
-
--
~.
rstVA TE M:U. LCCI.T.c:IH
uP~ox. .~~., CP'
s-J. WI' A't1)(Jt &,NCrU.
.
~\\\\~
.
~H.t"tN:t: S!UW AvtN'Jt SITE:. ~I/" ,.ruNt ..tl.
FIG\JRE J
PRIVATE WELL LOCATIONS
$KAW AVEHUE SJTE
'RO~~SED ,..",.N
-------
8f"
. . -
-
~,
..
[GENt) LL lOCATIOIt
. fttNOWf:
. MOMI'.:.t.E LOCAT1OfI
. 80M
FIGURE "NO WELL AND
MON'WRIE lOCATIONS
OOREt«)L NU£ SITE
SHAW .V",(O Pt.""
PAOfIOS't'
-------
J.'1'tAC'EXEft C
~UU8
.-
-------
Table 1
, Potential Chemicals of Concern - Ground Water
Shaw Avenue Dump Site
Range Arithmetic Maximum MCl fit ' MetG" Iowa Action
Frequency (JLg/l) Mean (t.2) (JLg/1) (...g/1) (...g/1) level
(JLg/1 ) (p.g/1 )
Viny1 Chloride 8/115 5 - 408 12.5 408 2 0 0.015 13)
1,l-Dich10roethene 17/115 2.5 - 166 6.2 166 ., 1 7(4)
1,2-Dichloroethane 7/115 2.5 - 44. 7 3.2 44.7 5 0 0.4' m
1,I,2-Trich10roethane 12/115 2.5 - 64.5 4.1 64.5 -- -- 3 (4'
Denzene 6/101 2.5 - 3180 139.2 3180 5 0 1 C3J
Toluene 6/101 2.5 - 2600 110 2600 1000 1000 1000 (4)
Xylene. 6/101 2.5 - 1610 81 1610 ' 10000 10000 10000 (4)
2-Nftroanf1ine 7/120 25 - 1600 47.1 1600 --
Arsenic 33/118 2.5 - 23000 585.6 23000 50 50 0.03 C3J
Cadmi"m 7/118 2.5 - 64.8 3.7 64..8 5 5 5(4)
Manganese' 88/118 7.5 - 3120 353.2 ,3120 -- --
Notes:
~on-detects were assumed to equal the detection limit when calculating mean concentrations for wel1s
which also exhibited positive detections.
(2) Non-detect~ were assumed to equal half the detection limit when calculating mean concentrations for
wells which 11 so exhibited positive detections. \ I
(3) Iowa actio" level is based on the "egligible Risk level (NRl) which is the one in a .i11ion
cancer risk level.
I:J Iowa action leve1 is based on the lifetime Health Advisory leve1 (HAL).
Federa1 maximum contaMinant 1eve' (MCl) and maximum contaminant 'eve' gOl1 (MClG).
-------
"'U
08
~:D
(;)0
-c:
z»
>,....
1-
~
"
table 2
Potent tal CheMtcals of Concern Surface Sotl
ShaM Avenue Dump Stte
t::..\ r:::.:. ....., (111,' r::.l, t:::.:, ,~, .::tr:, ......." ..... 1M .....
'"'''' j;,\'iC ...,.., boot .,...1
- - j"",,-
""'tt It ... .., ... ... .,. ... . .i, ... " ..
......,.... I.'. I. ... , ,. r. .11 t . ,... .... .... .
,....... f.'. I. U , ,. f. .11 , . Jr.' II ,If.' It
~". ,.. ,. " , ,. ,. '" , . '" .11 1ft, "'
'tdt' It ,.. '" u " .,. ,.. . " n " ..
~ JIII'-8l JI~ Jrt~ JrtI'.-I1 -"""I.. -"eA,1 -. ~t.. ~ -I*'tt.
ft. - ,....... ft., ,.. .. ". It ". " . ,.. II "' ...
''-M'" ... .. .. . ... ,.. '" .. .... "' '" "'
...... ... .. .. ... ,.. '" .. . ... lit '" III
.......~_.. II. n It . ft. .. ,It II ... . .. ...
....... .. . II . ft. ,. '" II.,. . .. 811
~~. .
1'1 ... t ,.., .1IM............t ..... ~.. ,.... .. "tnt,..... ,.. - ,................. '
, ... .."...., ,....... ,.. ..,.... ,--..t....... ... ,.. --... -, .... ,. ".....,. ,... - (_.......-4t-
, - ,.. ..-..... -..., ..... ... ........ ....,..,. -
. . " -..,,,' ....., ,.. line'"'' -".t ..... .....,..., ,... MIC'''' 'te" - ,.. ........., """'".
. .' ... -'''' .... """Hm..., ,.. -... If . ~.., - "" ,_t.. ,.. -- ..... "."'''''11.......... ""'... tilt ........ '"
... - ,.. _''''''1.... .. '... .....,,, It. ..... - .... ,..., ,.. ...,.,.. ...... '''''''-.'fIr ".. -"".... ,.. -...-..."'..
I. ........... ............ fir ..,...... ,....... ... ,." ....,....., ..... .' .
~
"
-------
. Tah1r. 3
Potent'.1 t~fC31~ of Conc~rn - 5ub~urf3ce Sol1
Shaw Ayenue Dump Site
111M .. ... .-.c' ... ...~ c:'~. .......~ ...... .... ...
,""'.., ,..,.., ,..,.., -l!;r:. ,..,," ...".. ,,......., :i;A'iC ...,... ......~.
- -'" _ -1!1~
...." n n ,. u. .ft ~ '1.1 '" '1.'. N .- ,. III
t..... , . , . " , u ~ ... U. '" .... " t.' " n
t..... . I.' I.' '.. ... ~ I' ~ 'It I.'.'" II 1M '.
,... ,. " It n ., '" ~ 'It n. tn "' ., III
A #III" .. . ., "' ~ "' , ,.., .., ~ .,. ... - ... . I.
.. ... . It ' . , " , tit' "" 'It II .... 1ft ... .
-""!d.. JdM .L ...... - ~ ""~J1 Jrt'!Jl ..IIt~ ~ .Jrt~ JdI'...JJ. ....,..L'
,....... .... ",. ,.. . ",. .... '11. "' ,.. ..- ... ... 1..,
........... .- "'. ,.. . "'. ... ,.. ." ,.. ..- .... ... ....
......... ... "'. ,.. . ",. ... '11. ." ,...- ,... .... In"
'''''''~1''' ..... ... ,.. . "'. '" ,..., tit ,.. ...... ... .... '1tN1
. I
'''''' ..... ... ,.. . "'.. ... '" . '" ,.. ..... .. ...... ....
.......,........ ...... ",., ,.. . "'. ... ,.. ." ,.. ..... "'" .... .....
~ .... "'. ,.. . "'. ... ,.. ." .,....... ..... .... ...
.........,..,.,...... ....., "'., ,..., - , ... ,.. ." ,.. ..... mt ..... ....
.....,,~ ,utfINI ... ... ,.. . ",.' ". ,... '" ,.. ..... ""' .... ,...
.....ca 'f1.,..... ...1"" .... ... . "' . "'. .. .'." ,It ,.. .... . ''''' ... ....
.......",.... .. "'. ,.. . "'. ... ,... ,,, ,.. ..... .... .... ....
.........t.~ .... "'. ,.. . .... ... ,.. ." ,.. . .... .... .... .... .
,""'..'~." 11M "'. ,.. . ".. ... ,... ,,, ,.. . II. - .... ....
.....c..,. ''''''''!iI .. "'. III . .... ,.. "... ,,, ,.. . ".', '" .. ...
."
08
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(50
ZC
» ),>
r--
r- -'-'.
...~
!-!!!1
1'1 ... "teet ......... "-' ....,...... ....... ..... ..... ft"''''''' ,fit - c...M'''''.
, ... ""1(818 ....... ,.. "..... .-..,...... .. ,lit ... ....... - .... .. ..te."'. ,.. - «,..4...A....".
. ,... .....,.... _ke ......... ",..,.. ""'''''
.. . . -...,.., ".... ,.. "_..... -.... ..,.. ..,...... ... ....... ..... fA .fIt ........., .........
......
-------
Tah1! 4
Potent'.1 Ch~.c.1s 01 tonc~rn - Ch~Ic.1 Ft11
'Shaw Avenue Dump Site
... ... ..... r:;. 1M' ......, .......
..., ..... .... J::rt ':'if.t t ......
...,.., ...,..t c..,..t c..".. c:f' ,..".1 ,... '''''''' .J~h. t.""", .
c.., .. ,..' .1 c..,... C..,...
. ... - -
........ ,.. ." ... ., '" ",. '" 'N-. ,m .ft m. '"
..,...... .. ... .. .". ".. ... '" ... ..'" 'N .l1li .,..,
"-tc ..... -. , .... It.- .. "" .... , '" -.. ..... 11tM ..... 11ft.
""'" h.I " 'U .9.1 ,.., ".. '" h.l. It.' . It.' .
t...... ,. It.. m 'N ,.. ,.. , '" ..... .- .n UII I..
te 't'" """, ... , t,.. , ",.. , "'"" , ".. , '" I,... "" ..... ....... .....
ttoo-... '1.' II .... .., .... ".' '" I.'. .... If .... -
t"'t ..". t.t . '.1. .... . .., ... I" .... ,.. I U .
t-..w II." '" .... , ., , Mt ' ,v , '" II.' - III .. ... ..
.... ,... me h" ... ."" , I'. ' '" ..... ... .. ... ""
,... '''' "1 .,.. '" "' .J8 ' '" .... ". .. III ,ft
......... '. I'" . "1 .., II' "'' '" M. ,... II' ".. I",
fila II A II .. ".. ".1 .., ... .~ , '" ..... '" .. .. ..
~, ':"8 I.' I." . ... . . ... "' 1.11. I.' " ., I
''''.' ... I.' ,U JU '11 '" '" .... .. .. .. III
........ .. .. ,.. "' ra' ,. '" I". " '" .. .. .
,,,- 1.1 1.1 . I.' . ... . . ... , '" I... '.", . ... I '
. ...... II' I.. - .... .... "1.1 '" lit. 1M ItN .... 1m
,..n.. ... II.' 1.1 . r.' It.. ... I" 1.1. . n.1 . If.' II
....... .t I.' ''' ... . II.' ... WI . I.'. 11.1 . 18.1 .
.- ... ..... I'" III ." .. , '" .... - .. .. -
. t,..... - II." ... ... . . I.' W' I... ".1 . ".1 I
-"'~ -r.t~ ~ .fie!. -:Jrt~L. ~ -Irt!!IL --Irt~ ~ ~ """'1. .fIel ~L
'''r....~'' 11- .. ".,.. .. IMOIIII , 8100IIII .. . IIIICIII8 .. .."""" II . "1 II. -.- II.'. ,,,... ...""
I.'''''''''' ...... .- . -"'. ,,..... , """ . '1_ . '''. ..... ~ ".,"' ,..... .,.,."
,..,._IIt.. ..., ...... , ......, ..... , ....... , ....... , lit _..- -- -- -"..
.
1.1'''' ...; ..., - ,. "'., ..., "'." " W. - I8t.I - ...
"
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1" .......",.................,..... ........ 'WI .... ","tat... ... - """"'"'...
, ,... "'''e8t. ,_",. ,.. ..,~ ~......,.. ef .... ,.. ...... - .... .. t.'ce"'. ,... -- t8lllWt......
. .~ ."8('.'" _,elt ..... II .. ",..,.. ......",
. . ,.. ..,. " --..,. ..........,... -,.. ..,..- ,.
.. . . _."'M' ft'''' .. "18("'" _rlt.1..... ,...n..tt ... "'"1" ,.... fII ... ........, ..........
. . . -...'''. ",.., ... 1118('8t" -.rlt., ..... ......... ... ....., .. ,.." .. ... ........., .,.......,.
POOR QUAL\TY
ORIGINAL
-------
t3b1~ 4 (tont.nu~d) .
Pot~nttl1 th~tca1$ 0' tonc~rn . theM'ca. F'1.
Shaw A,enue Dump Site
""' ...., ......, .... .....
... .... ..... ..., '"' "' tr' c:',1:. c .....
,..,.,. ,..,.,. ,..,. I'''r' c..,... 1''''[' c..,... I.., , '''''''' .~ ,..,.., t800f ..."".
C.., .. . C..,.t ''''''''
. 1 - ....,..t.
...,.~..... fttw... It.. ....., IJ .... ... ."', II . It.. "I .. ... I'.' ... ..
11(.,- ., ..... ". ... II. II "'. "., N.' "I II. . ".n . ,.
1.'-'"''''.''''' .. .., ... , m N' If ' . lilt , II . II" ,It II. ttt N.' ,.. "'
~....,- .t.. ...., " .11 f.. . lit' II .. It.. "' f. .. ".1 .. ..
..,....,,-...... .... ..., ~ " " f.. ''I' II .. It. ,It f. .. n.' .. If
'....-t,tc.......... 't.. .N ' 'It tI., II 'N' If " lit . II. ,.. .... ,.. JJI
..,- .... ...., ... ." f. ,., II . 1t. .1t f. ... .... ... ...
,..""...... .,. ..., " "' f.. ''I' II . 1t. .1t I. .. II .. If
"'- ... ...., " .., f. .' .... It. lit II. " ... N .
ta.1&J !"'..4-. ... ...., .. ., , " II . It. lit f. " ... ... "'
""........ .... ..., .. ..., II III '1 .. It.. lit II. ... W.. ... ".
.,.... C'''',, ..- - , - ,., ... ..., ., It. lit II. - .... - lit
-u
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ffio
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,-r-
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1'1 """'te'''''''''''''''''''''' till....... I"" .... ....."'.. till - ..............
7 .... ",''c,,, I_I". ,.. 8''''' c-......-., ,.. ,.. IIIIIIJ'" - .... I. Clke"" ,.. - c--.......
. ... ."..,.... -,tI' ..... .. .. .1'''''' ""'''''
- be ..,. " ........ c......,..,.....,.. .....- .
.. . . -...'"' ....., lip "88("'" _...1 ..lilt f.""" tit ..."'... ,.... ., ... ........., ",,",".
, . . -,'''tel """ ... "1tC'"'' ~tc.. ..... ........ tilt "'te'''' ..... .. ,.. ....,..., ..,.......
-------
Tab1e 5
Toxicity Va1ues for Chemica1s of Concern
Shaw Avenue Dump Site
08tc118 r~ fA'. "'ma ... \It tn 1l1li \lUll ..,.....
II," IfD
(tt-..,/I8) (181tt-.,) (tt-..,/I8) (18/t~,)
At. ,-
Mt.., ..0[001 IUI
...." 1.l(tOO 1.0004J CWIIAST '.0[041 lUST
"'18 '.0[042 811 1.0[001 lUST
It,., 1118 '..tOO '.o[04J IIAST 11&11 ...1 tOO lUST
CIa.. '.0[001 811 '.UtOO IIAST
Cl1C'.
01,.,. (WI) '.O[..a 811 ..11041 811
,*1t .'
c."., PI042 (e)
INn
&.88d '.0[042 1."04J (Pi 111m) '.0[042 '..001 '" III
111,,,-
-"II"" &.01-02 illS 1.0[001 IIAST
titre.,., '-OJ 001 IIAST
. tu,t 1.0[-02 IIAST '."-01 IlASt
""'II'.
I tift" 1.0004J 1111
SK'.
'" "'.
"..". , .00-oJ IIAST
2tIC 1.0(.02 IIAST
CSIIftt.. 1.0004J illS
'.&'41 1.".01 1.0(001 illS 1.".01 1111
_t~,,,.. atOl". 7.l1..a '.0(-02 1111 I.".oz 1111
".,t CUOl"" I.. tOO IIAST 1...01 IIASt
Ac8~. 1.0[.01 8lS
1.I00tcUOPOtt.ll8. '.0[.01 '.O[.OJ 1111 1.lItOO illS
C8 ,,",fm '.U..a 1.0[-02 8U '.U.oz 8U
1.1.0 tea \O"'9t.118. Ut 042 IIU '.II.oz IUS
1.1.1."tca ,."..u.. Ulo42 ..O[..a 811 '.7I.oz 811
Itue. 1.11.01 illS I...oz illS
T.t,eca IOI'ott.ll8. 1.11042 1.0[.02 IIAST IlIlS I....a lIAS'
~
11 IS . IIIt'ret,e It.. .lIfo-t tOft ')'It.
ill' . IIIII:~ Ift.ct A.a"I.~' 5-., Tat1t_. 111'" OIl",," n 10 .
&) . Eat\.~, r;: Ult~1':t! fl'Gl till p"'OCClt~ "\~\ft; ..:.. r"~OI.'lf 1.'-18".
t) . if;! c.a 1~~1at'd " IMT fOl' ca" ......nt ....e K ,I"t,*,- ~IIC ~ If ..02 88". (tU. t. IDt ., O£ """...
I~.) .
12
~...J
-1<
-
OCJ
-
a: a:
00
a
a..
-------
Tab'e 5 (Continued)
Toxicity Va1ues for Chemica's of Concern
Shaw Avenue Dump Site
011""" Or8' fA' .... \8U.. ... 'IU..
S '''' 1If...... II.,. 'ro 1If..-
(".",188' (."...,) ('''11,/11) (III'....,)
,.,.. 1,0(.01 1111 1.71.01 1111
0""*". 1...02 JUI
IU"..,.. 1...01 1111
.,,,. ("\Iff) 1..000 1111 '.11.02 IIASf
In...... ...... 1111
1.11\"'-'
I""".'U.
,,.,... "..02 IIASf
,...IIt.,.. "
utPtCt. 1.0(.01 1111
"."8.\"'. ,.0(.02 illS
PJ"'. 1.0(.02 illS
""0(1 )11It~"tC..
0,.,...
'U(2~\ft,11\UJ1)pII\III1tU 1.81.02 1.0(.02 JIll
It''IO(.)flllO''"\'''''
ItftJo(&)f 1010"88\11'"
1_~( I. I. J.u),,.....
18120(1 ),,....
0'''120(8.' )1.\11"8""
ItftJo(I.~.I)".,lt"
. .
..
~
illS - 11It.~.td II., ,"'O"Wttofl SJrt.
nWT - ...W. [ffro\ ~"I_..t S~.,1.t1.., '''I'f OoI!"\t" " to .
. - s~ 1.:( Irt C8'tw1.~.: 'rat \- J"*": ,,'1'1& 'lIS .U". ",.....-, 01' 1.1 ft.
.J .If~ ul;w1t\la .,IMT f., sau ....._M ....e II ~_s f"IPC" ~"I,a 1011.
.~,) . .'
"
"
POOR QUAL\TY
OR\G'NAL
--
11'" ,. - I. (fA Wl'UttG
13
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Tab1e 6 .
Risk Charaeterzation Sumnary (1)
Shaw Avenue Dump Site
III (d,nts, Tr,sp.ss,,.s, .nd ',e,." t Ion Se,n,,.,os
Chronic Hazard Index Excess
Scenario (by age group) Cancer
0-1 1.6 6-30 Risk
Lifetime
Current Resident/Trespasser ,~, <1 <1 <1 ::'.9£-06:.:.:::.
Future Residentl (3) Bedrock A .Bl..31 ':.:-,::.76.98 :--::::::.:::.23 .19 .. 3£-02: ..
now Unit Bedrock B 185.64 '178.85 ":':::.:::"54.49 '6E-02 "
Bedrock C ::.64.14 .:::::::::::60.81' '.::.:::::::/::18.28 ':5£-02 .:-:-::::.
Bedrock D {::::::;:::3;12 :::::::;:::::;:;::3.:32. <1 ::...::1£-03 ':'/::::::'
Bedrock E :::::.:.:.:;:::'2.49 '::::::::::::::::2.:72: <1 -:::::'.:-1E-D3 ::::::::::
Bedrock F "''':''309 '''::'::'329 <1 :.:".lE~~3 :::-:.::.:
:. ",:.:";;. '.:.:.::.:.:.::: .
Bedrock G :::.:.25.89 :::::..:31 .09 :::.:::::/:::::::':9.86. .:..:.1£~G2 ..
Alluvium B ':::.:.3.49 ':.:.:::::::::.:3.:67: <1 :.::1 £-03:..::.:
Alluvium C ::::::.:.:.:.4~14 ::::::.:::::::..4.84 .::::::::::::::::':::1.25 ':"..2E -03:::.::
Alluvium D :':...0.472 :::::::.:.,:::4.83 .:.:.:.:/,:::::.::1.2S :.:..:3£ -~3 . ..
Alluvium E :""':.3.67 ::':\:: 3. 83 <1 ":.:.1£-03..:.:::.:
Alluvium F ''''''''328 .:::.::::3 47. <1 ..::::1£-03..::::.
. .':- '.'::. :"'::':.' "
RecreaHon ,.., <1 <1 <1 : 7£ -05
."
Work,r Sc,n,rlos
. .
: Excess
Scenarios/Media Chronic Hazard Index Cancer
Risk
Lifetime
Current Surface So;l <1 6E-GS
Subsurface son <1 ''':1£-05
future Surfece Soi1 <1 :...:.:..1 E -05 "
" ...
Subsurface son .. . 1 21' . . .:::::.::lE-G3. :..:..:
':::::::~:::.:~::::::::::::::::::~::::~/:::::::::::::::- -~ -[[[
. . .
!2!w.
~ Shaded aT"lls repl"tSlM a ,,111: c:tIron'c."'zl", 1,*1 FIlter thin 1 Dr ucess ClftC8I' "lit Of
f"Mt.r &bin 1£-06.
- .
(2) Chrontc Mil", 1n:Se1 Ind IICtSS Clnc.r r"tsts fw tilt Cutftnt t'lstdent/tl"tSpuStr USI lcenarto
t'lpf"t"nt ttIe Cil8iMd rlKs associated .fUl uposure U tile lurlace IOU. surface ..t.r .111
ground 8t8r. .
U) Chron'c "'%1", trlfel Ind ucess Clncer ..tlh fw the future NS'denttl1 USt lC8na,.to
represent the CCIIIbtl'8d rtsh assoc'ated .,tl1 uposure U tile lurface IOn. surface water .111
the FC"nd ..ttr frce tile ftOlr unit 1tst8d. ."' . ~. ."..
(C) Ctlr"Ontc hUIP1S 'Illu Ind 'lcesS Clncer risks fw the future I"'tCP'Mtton use lcel'llr'o f'8Pf"tsent
-------
%AILE 7
,.oposm MO~"TTOJltNC ']lOCUM
SIiA "'. A VENU1 sm
Villyl CAloriM P. ,.~,.,., ff ~lfVrrcN
2,1 .DieJalfIf"NtIww .....,
2,2.Dielsl""oduw r....
Nnlfori"l Will J,2,2.rrie"'oronuw X,- J.NitronlJiwl .... "'_,8raa,
U- Wells
NW1 SIA - - SIA 'A
N\\'2 SIA - - 'SIA A
NW3 - - - SIA It.
NW4 - - - SIA It.
).fW6 -, SIA SIA SIA It.
).fW7 - - - SIA It.
NW9 - - - - SIA It.
t-M10 - - - .~S/A A
N\\11 - - - SIA A
MW12 - - SIA A
M\\13 - 5/1.. - SIA A
MW14 - 5/1.. SIA A
MW15 SIA A
M\\'16 5/1.. 5/1.. A
MW1' 5/1.. 5/1.. A
MW18 5/1.. A
~blol14tr: W,l1s
M\\'lA A A A
M\\'lB A - A A
MW2A A - It. A
MW3A - It. A
MW4A A A
).M'4B - ;.. A A
MW6A, A A
)1.\\'114 - A A
MW15A It. A
M\\'l58 - It. A
NW17A - - - It. It.
~fT""'ml S)'If"
~'.I'CPropoted) 011.. 011.. 011.. 011.. It.
~.2 CPropolld) 011.. 011.. 011.. 011.. It.
EW.3 CPropoted) 011.. 0/1..'" ' 011.. 011.. It.
,
EW-t crrOo~) 011.. 011.. 011.. 011.. It.
T...tznent Inf1Ul'ftt N N M N N
Pretrutznent Elfiuent Q)
(i! te1ected) NO> NO) NO> NO) NO>
-
Nois
A . S&~p1e IMua1I)'.
5/1... Sa:np1t ~zni"Mua1l)' lor two )'1&.8$, 8NluaD)' the:r-.ft.er.
Q/A. S&=Ip1. qu-.rwr1)' lor two )'1&.8$, annuall)' tnm8kc.
M . Sa:7\pJt znontily 10'1 two )'un, q\W1eT1)' thereafter
(1) . SatnpJt wte1r.1y 10'1 finl quarter.. '
QJ . Iina1 ,Inutflf IoI.:\pJin& ccmdu~td as part or PCm\'lI.7I)£S znonitcninS'
-------
TABLE 8
CHEMICAL FILL 1tEM'EDlAl
COST EST1MATE
DEED RESTRICTIONS
ACCESS CO~"TJlOL.IN.SmJ
f1XA nONlSOLtDInCA nON, CAPPING
AA'D MO~1TOJUNG
SHAW A VENtJE SITE
Estimlltt4 Cost rn
PrlMflt
Cqi&.r A-MAr Wordl 0/ 1"o,.r
~ DncriptiOfl c.lt c.., (2) A_lUll Co.t Prtlftlt Worth
.'
]. Deed ftStrictioN S '.2S0 S 0 S 0 S '.250
2. Excavate Underground
GuoUne Tank 5 4JOO $ 0 5 0 5 4.900
3. bI SiN r~tion/
Solic!ific:a:ion 5 .co6,400 S 0 S 0 S .co6,400
~. Uj) (includes II:CeSS control) S 30.300 S 2.QOO S 30,150 S 61.050
3. ~ Year Re',ew
(510,£:00/5 years) S 0 S 2.'/55 S 34.&."O 5 ~.8DO
Su~:otals S ~7 .!SO S 4.'/55 S 6~.550
TOTAL 1MrL.I.ME.''TAT10S COST FOR ALTER.'ZA'I'TVE ~ S 513 4..."(\ .
JWots
t1)
m
See Appendix E for demiled CDSt.
A vmge &Mual eosts over 30 yem, aCtual costs INY vary for specific yem.
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