United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R05-89/111
September 1989
Superfund
Record of Decision
Ott/Story/Cordova Chemical, Ml
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R05-89/111
3. Recipient1* Acceeaion No.
4. Title and Subtitle
SUPERFUND RECORD OF DECISION
Ott/Story/Cordova Chemical, MI
First Remedial Action
5. Report Date
09/29/89
7. Author(«)
8. Perioimlng Organization Rept No.
». Performing Organization Nairn and Addrae*
ia Pro|ect/Tuk/WorkUnltNo.
11. Contnct(C) or Gnnt(G) No.
(C)
(G)
12. Sponsoring Organization Nun* *nd Addram
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
IX Type of Report ft Period Covered
800/000
14.
15. Supplementary Note*
16. Abetrut (Limit: 200 word*)
The Ott/Story/Cordova site is in Dalton Township, Muskegon County, Michigan. Beginning
in 1957, various specialty organic chemical manufacturers operated at the site, producing
intermediate items used in making Pharmaceuticals, dyestuffs, and agricultural chemicals.
Soil and water contamination was noted as early as the 1960s, probably resulting from
discharge of production vessel clean out wastes and wastewaters to onsite unlined
lagoons, and drums of waste that were accumulated onsite. In 1977 several thousand cubic
yards of lagoon sludges and several thousand drums were removed by the State, and in 1982
an alternate water supply was provided to residents in the vicinity of the site.
Subsequent investigations detected significant degradation of Little Bear Creek and its
unnamed tributary, which flow past the site to the east, as a result of contaminated
ground water. Due to the complexity of the site the cleanup will be organized into two
distinct operable units. This first operable unit addresses the interception of
contaminated ground water entering the Little Bear Creek system. The second operable
unit will address contaminated soil, possible ground water remediation, source control,
and air and water monitoring. The primary chemicals of concern affecting the ground
water and surface water are VOCs including benzene, PCE, TCE, toluene, vinyl chloride,
and xylene; other organics including PCBs and pesticides; and metals including
arsenic.(See Attached Sheet)
17. Document An*ly*J« a. Descriptor*
Record of Decision - Ott/Story/Cordova Chemical, MI
First Remedial Action
Contaminated Media: gw, sw
Key Contaminants: VOCs (benzene, PCE, TCE, toluene, xylene), other organics (PCBs,
pesticides), metals (arsenic)
6. ldentifier»/Open-EndedT«
c. COSAT1 Reid/Group
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EPA/ROD/R05-89/111
Ott/Story/Cordova Chemical, MI
First Remedial Action
16. Abstract (continued)
The selected remedial action for this site includes pumping and treatment of ground
water that would otherwise enter the Little Bear Creek system using UV-oxidation, carbon
adsorption, biological treatment (activated sludge), and filtration with discharge to
surface water; and environmental monitoring. The estimated present worth cost for this
remedial action is $11,751,000, which includes estimated annual O&M costs of $1,500,000
to 1,600,000 for years 1-5.
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DECLARATION FOR THE RECORD OF DECISION
Statutory preference for treatment as a principal element of this Record of
Decision is met; five-year site review is required
SITE NAME AND IDCATION
Ott/Story/Oordova Site
North Muskegon, Michigan
STATEMENT. OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the
Ott/Story/Oordova Site, in North Muskegon,. Michigan, developed in accordance
with CERCIA, as amended by SARA, and to the extent practicable, the National
Contingency Plan. This decision is based on the administrative record file
for this site.
The State of Michigan concurs on the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not
addressed by implementing the response action selected in this ROD, present an
inninent and substantial endangermant to public health, welfare, or the
environment.
DESCRIPTION OF THE SELECTED REMEDY
This operable unit is the first of two planned for the site. The first
operable unit addresses the contamination of the Little Bear Creek system.
The function of this operable unit is to intercept the flow of contaminated
groundwater into Little Bear Creek and its unnamed tributary, and to provide
adequate treatment of groundwater thus collected. While the remedy does
address one of the principal threats at the site, the second unit will involve
possible remediation of contaminated site soils, remediation of possible
continuing sources of contaminants, possible remediation of the downgradient
contaminant plume, and accompanying air and water monitoring so as to properly
monitor remediation/recovery efforts. This first operable unit is consistent
with achieving a permanent remedy.
The major components of the current selected remedy include:
- Installation of extraction wells to intercept flow of contaminated
groundwater which would otherwise enter the Little Bear Creek system;
- Provide for adequate treatment of groundwaters thus collected such that the
resultant discharge will meet NPDES limitations as imposed by the program
administered by the State of Michigan;
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- Conduct environmental monitoring to ensure the effectiveness of the
remedial action.
DECLARATION OF STATUTORY
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 this site, and satisfies the statutory
preference for remedies that employ treatment that reduces toxicity, mobility,
or volume as a principal element.
Because this remedy will result in hazardous substances remaining on-site
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 of human health and the environment.
Date « I Signature (Regional Aftninistrffior)
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RECORD OF DECISION
DECISION SUMMARY
1. SITE NAME. LOCATION. AND DESCRIPTION
The Ott/Story/Cordova site is located in Dalton Township, Muskegon County,
Michigan, approximately five miles north of the City of Muskegon (see Figure
1) . The site is in what may be termed the northernmost vicinity of the Greater
Muskegon area.
2. SITE HISMORY AND PJJ?OHfPME^^ ACTIVJ.'!' I >*!S
Site operations began approximately 1957. The site was host to various
specialty organic chemical manufacturers. Products made over the span of
active operations included intermediate items used in the making of
Pharmaceuticals, dyestuffs, and agricultural chemicals.
Production vessel clean out wastes and wastewaters were all initially
discharged to on-site unlined lagoons and allowed to dissipate by seepage. The
accumulation of drums of waste was also allowed to occur.
By the 1960s, signs of water and soil contamination were .beginning to be noted.
A program, later characterized by sane Michigan Department of Natural Resources
(MDNR) members as largely ineffectual, to slow the spread of a plume of
groundwater contamination, was begun.
By 1977, with the then site owner bankrupt, a removal program was undertaken by
the State of Michigan and financed by the new site owner. Several thousand
drums and cubic yards of lagoon sludges were removed.
In 1982, the site was placed on the National Priorities List. Also in 1982, an
alternate water supply was installed in the vicinity of the site by the parent
company of a former site owner in settlement of a citizens' suit. In January
1988, U.S. EPA's REM IV contractor began RffmRdial Investigation (RI) field work
at the site.
Three distinct sets of site owner/operators have occurred. The Ott Chemical
Company began operations at the site in the 1950s as an independent company.
In 1965, Corn Products Company, now CPC International, purchased all stock of
Ott Chemical. In 1972, CPC sold assets that comprised Ott operations to story
Chemical. In late 1976-«arly 1977, Story began bankruptcy proceedings. In
late 1977-early 1978, Cordova Chemical Company of Michigan purchased the site
after entering into an agreement with the State of Michigan. The agreement
called for Cordova to destroy or neutralize phosgene gas supplies left at the
site, and to finance Michigan so as to remove drums of waste and lagoon
sludges. In return, Michigan agreed to limit Cordova's liability for future
site releases caused by past activities.
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0 2000
SCALE IN FEET
OSC SITE
*:?3
Lake
Michigan S
Figure 1
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The Ott/Story/Cordova Site, circa 1970.
Note the lagoons in the center background.
View is facing north.
IffWTV,
if?'-1
'i*A
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In 1985, a notice letter advisory of potential site liability and offer to
conduct a site RI/FS was sent to Cordova and CPC by U.S. EPA. No settlement
was reached over private conduct of the RI/FS; hence in May 1986, U.S. EPA
informed these PRPs in writing of the Agency's decision to perform the RI/FS.-
In March 1989, U.S. EPA sent demand letters for cost recovery purposes to CPC
and Cordova. In May 1989, U.S. EPA informed Aerojet-General and Swanton-Story
Corporation of potential liability as regards this site and sent demand letters
to these firms. Both Aerojet-General and Swanton-Story Corp. are considered as
PRPs. Aerojet owns Cordova Chemical. Swanton-Story is what remains of Story
Chemical after bankruptcy proceedings.
In August 1989, PRPs were given notice via a Section 122 (a) letter of the
availability of the Proposed Plan Focused Feasibility Study, and the start of
public comment period.
3. COMMUNITY PARTICIPATION
A RI/FS "Kickoff" availability session was held near the site in November 1987.
Upon its completion in April 1989, a copy of the RI report was made available
to the public at the information repository maintainpd at the Dalton Township
Public Hall and also the Walker Memorial Library in North Muskegon. The RI was
also made a part of the administrative record file Tnaint-.a-itvaH in Region 5 and
at the local facilities noted above. The Focused Feasibility Study (FFS)
notice of availability was published in the *f »i«ff*y*v Chronicle on July 27, 1989
to initiate a public comment period on the alternatives from August 1, 1989 to
August 31, 1989. In addition, a public meeting was held on August 16, 1989.
At this meeting, representatives from EPA and the Michigan Department of
Natural Resources answered questions about site conditions, problems, and
remedial alternatives under consideration. Subsequently, EPA extended the
period for receipt of written comment to September 19, 1989. A response to the
comments received during this period is included in the Responsiveness Summary,
which is part of this Record of Decision. This decision document presents the
current selected remedial action for the Ott/Story/Cordova Site in North
Muskegon, Michigan, chosen in accordance with CERCXA, as amended by SARA, and
to the extent practicable, the National Contingency Plan. The decision for
this site is based on the administrative record file.
4. SCOPE AND ROLE OF OPERATE "OTTC1
As with many Superfund sites, the problems at the Ott/Story/Cordova site are
complex. As a result, U.S. EPA proposes to organize the work into two distinct
units. These are:
- An operable unit (OU) which will adrimw the interaction of contaminated
groundwaters presently entering and degrading the Little Bear Creek system.
To the degree practicable, this OU will not be inconsistent with other
possible site remedial action.
- A second operable unit which will address the ispav»s of contaminated site
soils, possible groundwater remediation, source control, and air/water
monitoring efforts needed to evaluate effectiveness and duration of remedial
actions.
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This Record of Decision concerns the first operable unit noted for the
Ott/Story/Cordova site. RI data show that Little Bear Creek and its unnamed
tributary are degraded by the discharge of contaminated groundwater. The '
Ott/Story/Cordova site served and continues to serve as the principal source
of the groundwater contaminants. Little Bear Creek has been degraded to the
point that the Michigan Department of Public Health found it necessary to
request the Muskegon County Health Department to post signs in the stream bed
warning potential users of contaminated water.
The second OU will consider the threats posed by site soils/ and will consider
what if any restoration efforts should be undertaken for the contaminated
aquifer. This aquifer once served as a drinking water supply, but in its
present state poses a threat to potential future users.
5. SUMMARY OF SITE CHARACTERISTICS
An important site characteristic at Ott/Story/Cordova is the sandy nature of
site soils which result in a high permeability. Fast waste seepage practices
and subsequent plant spills/releases have resulted in many increments of
pollutant introduction into the groundwater system. The RI revealed over 90
different organic compounds in the groundwater, of which 32 are classified as
priority pollutants. Surface and subsurface soils at Ott/Story/Cordova were
also found to be contaminated.
The surface water samples collected from Little Rpar Creek and its unnamed
tributary were found to be contaminated with many of the same compounds found
in other contaminated media at the site. The sources of the surface water
contamination are seeps of upwelling groundwater located along Little Bear
Creek and its unnamed tributary. The following table shows higher contaminant
concentrations at various spots in soil, groundwater, and surface water around
the Ott/Story/Cordova site:
SURFACE SOIL
(results in ug/kg)
POINT
SF-02W
SF-20
SF-6
Benzoic Acid
4,4'-DDT
1,2-Dichlorobenzene
Benzoic Acid
4-Chloroaniline
OQNC.
6000
25000
11000
75000
1200
SUBSURFACE SOIL
(results in ug/kg)
SB-07
SB-24
1,1,1-Trichloroethane 17000
xylene 79000
Toluene 1600
1,4-Dichlorobenzene 7600
1,2-Dichlorobenzene 13000
Hexachlorobenzene 7800
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GROUNDWftTER
(results in ug/1)
CW-12(near unnamed
tributary)
Vinyl Chloride 50000
1,1-Dichloroethene 1100
1,1-Dichloroethane 2400
1,2-Dichloroethane 110000
Toluene 3200
Benzoic Acid 1300
GRCUNDWftTER
(results in ug/1)
SURFACE WATER
(results in ug/1)
POINT
OW-9
(about 1/3 distance
from former plant
to Creek)
Near confluence of
unnamed tributary
and Little Bear
Creek
Vinyl Chloride 130000
1,1-Dichloroethene 7900
1,1-Dichloroethane 6300
1,2-Dichloroethane 21000
Chloroform 85
Vinyl Chloride 52
1,1-Dichloroethane 26
1,2-Dichloroethane 140
Benzene 26
Toluene 22
Aniline 17
Tentatively Identified Oonujoupd-'g (TXCs)
N-Methyl Benezeneamine 24
N,N-Dimethyl Benzeneamine 100
N-Ethyl Benzeneamine 27
6. SUMMARY OF SITE PTgK?
Introduction
Numerous chemical compounds were detected during the course of Ott/Story/
Cordova field investigations. As is explained in further detail in the
Remedial Investigation report, some 90 organic compounds were detected in
groundwater, 15 in surface water samples, and over 200 organic compounds were
detected in site soil samples. Inorganic compounds were also detected in these
same environmental media. Data sets were evaluated to consider those chemicals
above background levels, toxicity constants for noncarginogens and carcinogens
were reviewed, and the degree of occurrence of a given substance at the site
was considered.
Based on this evaluation, twenty two indicator chemicals were selected at the
Ott/Story/Cordova site which appeared to not only to be present in- significant
concentrations, but also exhibit the potential for relatively high toxicity.
These substances are:
1,1,2-Trichloroethane
1,2-dichloroethane
1,1-dichloroethene
trichloroethene
carbon tetrachloride
benzene silver
heptachlor epoxide barium
xylene zinc
toluene copper
4,4'-DDr nickel
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vinyl chloride PCB cyanide
chloroform dichloromethane arsenic
tetrachloroethene
EXPOSURE ASSESSMENT
During early production periods at the site, releases of contaminants occurred
either to the air or soil. Since production activities have now been
curtailed, it is assumed that all present releases from the site resulted from
previous releases to soil.
Once in soil, further releases can occur by movement of contaminants into
grcundwater and the subsequent discharge to surface water, volatilization into
the air or suspension of contaminated dusts into the air, or runoff of surface
water that may carry contaminated soils. Because of the porous nature of soils
at Ott/Story/Cordova, soil runoff to surface water is considered as minor
pathway for contaminant movement. However, contamination of grcundwater and
its resultant movement is of major concern at Ott/Story/Cordova.
The movement of contaminated grcundwater poses several exposure pathways.
Users of grcundwater are considered a potentially exposed population.
Formerly, several residents near the site were supplied by individual
grcundwater wells. In 1982, consequent to a settlement of a citizens' suit, a
past owner/operator of the site funded an extension of an alternate water
supply to the area. In recent years, the Muskegon County Health Department has
found it necessary to warn residents near the site not to use groundwater for
watering lawns or gardens; such usage can present either an ingestion or
inhalation pathway.
Other pathways are presented when a portion of the contaminated grcundwater
upwells into the Little Bear Creek system. Consequently, aquatic organisms are
exposed to pollutants. Volatilization of contaminants from surface water into
the air represents a pathway. Ingestion or denial contact with surface waters
by human populations is also a route of exposure. Signs warning potential
users of contaminated water in the stream have been posted by the Muskegon
County Health Department at the request of the Michigan Department of Public
Health. Although the number of workers at the existing plant now consists of a
minimal "skeleton crew", contaminants in soils onsite may lead to exposure via
dermal contact or ingestion to those workers.
The grcundwater at Ott/Story/Cordova may be classified as a Class II supply.
Prior to the present contamination, groundwater once served as a source of
drinking water.
In developing exposure scenarios, both "base case" and "high exposure case"
were considered. The base case represents an estimate of average exposures,
using average concentrations and contact rates. The high exposure case uses
highest detected environmental concentrations and higher than normal contact
rates. The number of base exposure visits per year were estimated at 0 (ages
0-1), 2 (age 1-6) and 10 (age 6-76). High exposure visits were estimated at 0
(ages 0-1), 4 (ages 1-6), and 20 (ages 6-76). Base exposure visits were
assumed to last 3-4 hours; high exposure visits 6-8 hours. Pending age group,
air inhalation was assumed to be from 7.5 m3/day to 20 m3/day. Soil ingestion..
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s
rates for base cases were 50 mg/day for all age groups except children aged 1-
6 years. For this group, the rate of soil ingestion was 100 ing/day.
TDXICTIY
The degree of toxicity which may be posed by a given chemical may be described
in part by its acceptable intake for subchronic exposure (AIS) , its reference
dose or acceptable intake for chronic exposure (AIC) , and in the case of
carcinogens by its carcinogenic potency factor. Values for AIS and AIC are
derived from information available from studies on animals or human
epidemiologic studies. These values are normally reported in mg/kg body
weight/day/ and generally represent the highest calculated exposure level below
which the given adverse effect will not occur. A carcinogenic potency factor
is expressed as lifetime cancer risk per mg/kg body weight/day/ a™* is
estimated at the upper 95 percent confidence limit of the carcinogenic potency
of a given chemical.
Cancer potency factors (CPFs) have been developed by EPA's carcinogenic
Assessment Group for estimating excess lifetime cancer risks associated with
exposure to potentially carcinogenic chemicals. CPFS, which are expressed in
units of (mg/kg-day) "*, are multiplied by the estimated intake of a potential
carcinogen, in 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 CPF. Use of this approach makes underestimation of the actual cancer risk
highly unlikely. Cancer potency factors are derived from the results of human
epidemiological studies of chronic animal bioassays to which animal-to-human
extrapolation and uncertainty factors have been applied.
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. 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.
The following two tables describe AIC, AIS, and carcinogenic potency factors
for indicator chemicals at the Ott/Story/Cordova site. The third table lists
the weight of evidence for the various categories of potential carcinogens.
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AIC AND AIS VALUESIFOR INDICATOR
CHEMICALS AT THE OTT/STORY/CQRDOVA SITE
Aocentatole Intake
Inoestion Route
Inhalation Route
Indicator chemical
1,2-Dichloroethane
1,1-Dichloroethene
Arsenic
Carbon Tetrachloride
Vinyl Chloride
Chloroform
Tetrachloroethene
Benzene
1,1,2-Trichloroethane
Heptachlor EprHtixip
Silver
Barium
Zinc
Copper
Nickel
Trichloroethene
toluene
Cyanide
Methylene chloride
Xylene
4,4'-DDT
PCS
Subchronic
(AIS)
0.21
0.037
0.02
0.43
0.1
Chronic
(AIC)
ma/to/day
0.009
0.0007a
0.01
O.Ola
0.004a
0.0000133
0.003
O.OSa
0.21
0.037
0.02a
0.30
0.02
0.06
2a
0.0005
Subchronic
(AIS)
mg/ko/dav
Chronic
(AIC)
0.0014
0.1
1.5
0.69
0.00014
0.01
1.5
0.4
Primary Source: USEPA, 1986a
a - Source: RfD; EPA IBIS database (12/1/88)
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10
CARCINOGEN POTENCY FACTORS FOR INDICATOR
CHEMICALS AT THE OTT/STOPY/CORDOVA SITE
Indicator Chemical
1,2-Oichloroethane
1,1-Dichloroethene
Arsenic
Carbon tetrachloride
Vinyl Chloride
Chloroform
Tetrachloroethene
Benzene
1,1,2-Trichloroethane
Heptachlor Epoxide
Silver
Barium
Zinc
Copper
Nickel
Trichloroethene
Toluene
Cyanide
Methylene chloride
Xylene
4,4'-DDT
PCB
Ino»stion Route
Potency
Factor EPA Weight
fmct/loa/d) "^ of Evidence
Inhalation Route
0.091
0.58
1.65b
0.13
2.3
0.0061a
0.051
,029a
.0573
0.
0.
9.1
B2
C
A
B2
A
B2
B2
A
C
B2
0.011
0.0075
0.34
7.7
A
B2
B2
B2
B2
Potency
Factor
fna/ker/d)"1
0.09la
1.16
15a
0.13a
0.295a
0.08la
0.0033a
0.029a
0.057a
9.1
1.19
0.013a
0.0143
EPA Weight
of Evidence
B2
C
A
B2
A
B2
B2
A
C
B2
A
B2
B2
B2
B2
Primary Source: EPA, 1986
a - Source: RfD; EPA IRIS database (revised 12/1/88)
b - USEPA, 1987
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11
EPA WEIGHT OF EVIDENCE
CATEGORIES FOR POTENTIAL CARCINOGENS
EPA Description
of Group P9grrpi.ptj.on of Evidence
Group A Human Carcinogen Sufficient evidence from
epidemiologic studies to support a
causal association between
exposure and cancer •
Group Bl Probable Human T.Jm-it-ori evidence of
Carcinogen carcinogenicity in humans from
epidemiologic studies
Group B2 Probable Human Sufficient evidence of
Carcinogen carcinogenicity in animals,
inadequate evidence of carcino-
genicity in humans
Group c Possible Human Limited evidence of carcino-
Carcinogen genicity in animals
Group D Not Classified Inadequate evidence of
carcinogenicity in animals
Group E No Evidence of No evidence of carcinogenicity
Carcinogenicity in at least two adequate animal
in Humans tests or in both epidemiologic and
animal studies
7. RISK CHARACTERIZATION
Excess lifetime cancer risks are determined by multiplying the intake level
with the cancer potency factor. These risks are probabilities that are
generally expressed in scientific notation (e.g. , IxlO""6 or 1E-6) . An excess
lifetime cancer risk of IxKT6 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.
Potential concern for noncarcinogenic effects of a single contaminant in a
single medium is expressed as the hazard quotient (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.
-------
12
The Agency considers excess cancer risk in the range of 10"4 to lo""7 as
protective of human health. The risk level of 10"^, which represents a
probability of one in one million that an individual could contract cancer
under the conditions of exposure, is often used as a "benchmark" of protection.
Given the relative proximity of potential receptors to the site, a risk level
of 10"6 appears appropriate for this site.
Given current land usage, the estimated excess cancer risks for three indicator
chemicals are greater than 10"6 under base exposure assumptions. These are:
PATHWAY INDICATOR CHEMICAL CANCER RISK (base case)
inhalation 1,2-dichloroethane 7 x 1(T5
inhalation 1,1-dichloroethene i x 10~5
inhalation benzene 2 x 1CT5
Hence, a potential health risk is posed due to inhalation of ambient air.
Given current land usage, excess cancer risks were greater than 10~6 under high
exposure assumptions for six indicator chemicals. These are:
PATHWAY INDICATOR CHEMICAL CANCER RISK (high exposure case)
inhalation 1,2-dichloroethane 6 x lO"4
inhalation 1,1-dichloroethene 2 x KT4
inhalation benzene 1 x 10"4
inhalation 1,1,2-trichloroethane 1 x 10""6
ingestion Arsenic 1 x 10""6
ingestion PCS 6 x 10~^
Hence, a potential-health risk is posed due to inhalation of ambient air for
the first four rmrounds given above, while a health risk due to incidental
ingestion of soils at the facility is posed by the last two. It should be
noted that volatilization of chemicals from surface water is a source of air
pollutants. Additive excess cancer risk due to inhalation of indicator
chemicals is 1 x 10"4 for base exposure and 9 x 10"4 under high exposure
conditions.
Regarding future land usage, it was areaTmpd that the site might undergo either
residential or commercial development. For residential development, ingestion
of DOT contaminated soil may pose a problem under high exposure conditions. A
chronic hazard index of 1.67 (XL) was calculated for children ages 1-6. Future
residential developmental of the site would also pose a potential soil
ingestion health risk for carcinogenic substances as shown below:
PATHWAY INDICATOR CHEMICAL CANCER RISK (base) (high)
ingestion Arsenic 3 x 10"6 3 x 10"5
ingestion PCB 4 x 10"6 4 x 10"4
ingestion 4,4'-DDT - 3 x 10"5
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13
For future commercial development of this site, a potential soil ingestion
health risk for carcinogenic substances in posed under a high exposure scenario
as shown below:
INDICATOR CHEMICAL CftNfPTl RISK
Arsenic 2 x KT6
PCS 3 x 10~5
4,4 '-DDT 2 x KT6
Risks to potential ground water users were also calculated. Risks were
estimated assuming that a given monitoring well served as a water supply
source. Chronic hazard index values and base case cancer risks were estimated
for indicator chemicals found in each well.
The chronic hazard index value exceeded unity in 19 monitoring wells, {fence,
were the groundwater used in its present state, it may pose a health risk with
regard to noncarcinogenic chemicals.
With regard to carcinogenic indicator chemicals, cancer risks for at least one
compound exceeded 1 x 10"6 in 22 wells. Particularly striking were results
obtained in monitoring wells OW12 and OW9. vinyl chloride concentrations in
these wells were found to be at such levels that the excess cancer risk from
this compound alone was found to approach 1. Eight other wells exhibited
instances of either vinyl chloride or 1,2-dichloroethane exceeding cancer risks
of 1 x.10'1.
These results indicate that any potential ingestion of groundwater from certain
areas at the Ott/Story/Oordova site poses significant health risks.
The above discussions indicate that the risks from current and potential
exposure to contaminated groundwater, soil, and surface water are unacceptable.
Actual or threatened releases of hazardous substances from this site, if not
addressed by implementing the response action selected in this Record of
Decision, present an imminent and substantial endangerment to public health,
welfare, or the environment.
8. DEr^CRIPl'lON OF
Alternative 1 - No Action
Section 300. 68 (f) (1) (v) of the National Contingency Plan requires that the no
action alternative be carried forward for consideration in the detailed
analysis of alternatives as a baseline for comparison of other alternatives.
Under this alternative, no funds would be expended for monitoring, control, or
cleanup of contamination associated with the Little Bear Creek system.
Discharges of contaminated groundwater will continue to enter the unnamed
tributary and Little Bear Creek if no action is taken.
The no action alternative does not provide protection of human health and the
environment, and does not comply with applicable or relevant and appropriate
Federal and State requirements (ARARs) .
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14
Alternative 2 — Extraction. Organic Cont'aipiT'^nt Remove ~j ^gprption. Biological
Trg'rVtanent . Stream Discharge
The major features of this alternative include locating groundwater extraction
wells in the vicinity of entry of seeps of contaminated groundwater into Little
Bear Creek and its unnamed tributary, physical-chemical treatment to provide
initial removal of organic contaminants, filtration to provide further
contaminant and suspended solids removal, and biological treatment so as to
yield enhanced removal of organics prior to -stream discharge.
Modeling suggests that an appropriate combined extraction rate would be
approximately 400 gpm. This should provide effective interception of
contaminated groundwater within the unconfined aquifer.
The specific types of physical-chemical organic contaminants removal (e.g. , UV-
oxidation, air stripping) , filtration (e.g. granular activated carbon) , and
biological treatment (e.g. activated sludge) , will be determined in the
Remedial Design phase through engineering design and analysis and the
competitive bidding process.
Effluent quality must meet conditions as imposed by the Michigan-administered
NPDES permit system. Air emissions must be shown to be in compliance with
Michigan Air Rule 901 as demonstrated by Air Rule 203. Solids/sludges
generated during wastewater treatment would be handled in accordance with RCRA
rules on evaluation and management on and off site. Technical requirements
imposed will be complied with, but since the action is on-site, Section 121 (e)
of CERCLA does not require compliance with administrative procedures.
It is estimated that this alternative would take approximately 18 to 20 months
to implement. Its capital cost is $5,030,000 and present worth cost is
$11,750,000. Cost may vary somewhat depending on carbon adsorption system
selected, as well as physical-chemical treatment chosen.
Alternative 3 — Sl^1]^^ Wa^l- Extraction. Organic Contsp^^ia^t Removal.
Biological Trp^atmpnt. Stream
This alternative would utilize most features of Alternative 2. A principal
difference is the installation of a slurry wall of approximately 1000 feet in
length and 90 feet deep near Little ppar Creek. A primary benefit of such a
wall would be the expected drop in volume of groundwater requiring treatment.
Fewer extraction wells, with a total pumping rate of approximately 150 gpm,
would be required.
The total time required to bring this alternative on line is estimated at
between 19 and 21 months. Its capital cost is placed at $4,760,000, and its
present worth is estimated as $9,500,000. Such costs may vary somewhat
depending on design selection of carbon adsorption or physical chemical
treatment chosen.
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15
Alternative 4 — Extraction. Oroanic Contaminant Removal. Adsorction. POTW
This alternative would utilize most of the features of Alternative 2, with the
exception of no biological treatment and discharge would be routed to the local
POIW. Acceptable priority pollutant pretreatment conditions have been received
from Muskegon County officials responsible for publicly operated treatment
works (POIW) compliance. It is believed that such conditions can be met
through employment of initial organic contaminant removal and filtration steps.
Construction tine for this alternative is estimated at 18-20 months. Capital
costs are placed at $3,140,000, with a present worth of $8,840,000.
Alternative 5 ~ P^^TTY Wall. Extraction. Organic Contamir>ant Removal.
Adsorption. POIW Discharge
This alternative combines features of Alternatives 3 and 4. Via slurry wall
construction and employment of extraction wells, approximately 150 gpm of water
would be discharged into the POIW- system after initial treatment for organic
contaminant removal and adsorption. Construction time for this alternative is
estimated at 19-21 months. Capital costs are placed at $3,600,000, with a
present worth of $7,380,000
Alternative 6 - Trench Interceptor. Stream Di«vfrarqe.
This proposal considers the installation of a french drain system of about 1000
feet in length placed on the west bank of the Little Bear Creek system. Trench
backfill permeability would be on the order of 1 x 10"1 ft/sec, which would
allow some 450 gpm of groundwater to enter the trench. Sloping would be from
north to south, such that water collected would drain to a wet well equipped
with a submersible pump. As advocated by one of the site PRPs, such flow would
then be routed into the Muskegon County POIW. This alternative as originally
proposed did not have a provision for pretreatment. As originally proposed by
the FRP, this alternative would not have met ARARs, and would have
cost approximately $1,000,000. In order to give this concept full review, the
Agency assumed a treatment system as noted in Alternative 2. Capital costs
then are placed at $5,500,000, with a present net worth of $12,200,000. Time
for installation is placed at 19-21 months.
SUMMARY OF COMPARATIVE ftfl&EYSIS OF ALTERNATIVES
It is now appropriate to discuss some of the relative strengths and weaknesses
of the alternatives given above. Later, each of the alternatives will be
reviewed as to how well they compare to the criteria of overall protection of
human health and the environment, compliance with ARARs, long-term
effectiveness and permanence, reduction of taxicity, mobility, or volume
through treatment, short-term effectiveness, implementability, cost, state
acceptance, and conraunity acceptance.
It should be noted that of the criteria listed above, overall protection of
human health and the environment and compliance with ARARs are considered as .
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16
threshold. If an alternative fails to meet these two criteria, it will not be
considered further. The other criteria will be used to evaluate further those
alternatives that are protective and are in compliance with ARARs.
Alternative 1 - No Action
As we have seen, signs warning of contaminated water have been placed in Little
Bear Creek. A risk has also been identified with air inhalation at points
within the stream's valley, and a chloroform level in Little Bear Creek
exceeded the appropriate ambient water criterion by a factor of nearly two-
fold. Additionally, levels of benzene, vinyl chloride, and 1,2-dichloroethane
exceed drinking water criteria within Little Bear Creek. Vinyl chloride levels
also exceed by over a sixteen-fold a Michigan criterion on the presence of
toxic substances at levels which are or may become injurious to the public
health, safety, or welfare. Benzene levels in Little Bear Creek exceed U.S.
EPA ambient water quality criteria for carcinogenic protection of ingestion of
water and organisms by nearly forty-fold. Such conditions are not protective
of human health and the environment. Consequently, the No-Action alternative
is not appropriate for this site.
Alternative 2 ~ Extraction. Organic Con^nujprit PeT**1**?!, ^gprption. Biological
stream
This alternative utilizes a ground water pumping and treatment scenario, and
then discharge into Little Bear Creek for interception of the contaminant
plume.
Back in the days of Ott Chemical operation, purge wells and some water supply
wells had to be abandoned (or suffered greatly curtailed pumping capacity) due
to fouling. Such fouling may have been caused by the pollutants in the
groundwater. However, it is now felt that establishing a regularly - scheduled
program of well maintenance and downtime would help to avoid such problems.
The extraction wells envisioned by this alternative would presumably be of 8"-
10" diameter.
Moreover, if a well was inoperable during maintenance, the remaining wells
could be pumped at higher rates to try to extend their zones of coverage.
Alternative 3 — Sl^^rrv w^llj Extraction. Organic Corrt^iflirpnt Removal.
Absorption. Biological Treatment. Stream Disch?rq*»
From strictly engineering terms, this alternative has certain advantages over
Alternative 2. Although initial capital cost is slightly higher, volume of
water to be treated is substantially reduced. This results in lower
maintenance costs through reduced power demands and dosage requirements. Solid
waste handling costs would also be lower, due to reduced spent carbon and
sludge generation.
However, Alternative 3 also has drawbacks. In arranging access, it is easier
to secure a few well installation points as opposed to a continuous strip of
land some 1000' long. Moreover, most of this strip of land would be behind
residential properly along Central Road. Possible air emissions may be created
in excavating for the slurry wall. Given that one would be working in a zone ,
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17
Also, the slurry wall integrity once in place, nay have sane cause for concern.
Given the complex nature of the overall contaminant blend in the groundwater,
the materials in the groundwater could pose sane possibility of attack or
breakthrough of the slurry wall.
JV€ _
Contaminant Reroov*!, ^g^rption. POIW Discharge.
Compared to Alternatives 2 and 3, both of these alternatives offer significant
capital cost savings, since it is assumed that biological treatment can be
provided by the POIW and not built in to the alternative.
However, Alternatives 4 and 5 both pose drawbacks as well. As RI fieldwork was
proceeding in 1988, local newspapers carried accounts of by-passing of the
Muskegon County POIW. Moreover, it is proposed that this POIW undergo a large
expansion of nearly 10 mgd. However, the Muskegon County Wastewater Division
is not receptive to dedicating any of this planned expansion to accept flows
from the Ott/Story/Cordova site. Instead, separate financial commitment for
additional capacity may be required before this remedy can be implemented.
6 ~ Trench/French Drain. S^"r*y*m Disctv^roe
As initially proposed to U.S. EPA by the PRP, this alternative would not have
met ARARs because it had no provision for treatment of water collected.
In terms of implementability, this alternative poses access problems as noted
in the Alternative 3 discussion above. Extensive excavation in soils in which
the groundwater is highly contaminated may pose an air emissions problem for
nearby residents. If excavated soils are highly contaminated a considerable
solid waste management issue is posed.
Maintenance of the trench so as to promote continued high rates of infiltration
over time are not explored by the stated alternative. It can be theorized that
biological fouling of the trench may be possible. If so, the rate of
infiltration into the trench would be reduced. If infiltration rates were
reduced sufficiently, the trench would not serve as an effective means of
intercepting contaminated groundwater, and pollution of Little Bear Creek would
resume. Furthermore, underdrain installation would result in bypass of a
portion of the existing stream bed, resulting in possible greater disturbance
to natural habitat.
APPT.T(7ART1«| OP PFT||^VANr AND APPROPRIATE REQUIREMENTS
FOR THE OTT/STDRY/ODRDOVA SITE
CERCLA Section 121 requires that remedial actions comply with the requirements
of all Federal and duly established State environmental regulations. Those
pertinent regulations are referred to as Applicable or Relevant and Appropriate
Requirements (ARARs).
Applicable requirements mean those cleanup standards, standards of control, and
other substantive environmental protection standards, requirements, criteria,
or limitations promulgated under Federal and State law that specifically
-------
IS
address a hazardous substance, pollutant, contaminant, remedial action,
location, or other circumstances at a CERdA site. Applicable requirements are
specific to the conditions present on the site for which all of the
jurisdictional prerequisites of the law are satisfied.
Relevant and appropriate requirements are those cleanup standards promulgated
under Federal and State regulation, that, while not "applicable", address
problems or situations sufficiently similar to those encountered at the CERCXA
site that their use is well suited to the particular site. A requirement that
is judged to be relevant and appropriate receives the same degree of compliance
as if it were applicable.
To-be-considered (TBC) materials are non-promulgated advisories or guidance
issued by Federal or State government that are not legally binding and do not
have the status of ARARs. However, in many circumstances TBCs will be
considered along with ARARs as part of the site risk assessment and may be used
in determing the necessary level of cleanup for protection of human health for
the environment.
ARARs apply to actions or conditions located onsite and off site. Qnsite
actions implemented under CERdA are exempted from having to meet
administrative requirements of Federal and State regulations such as permits as
long as the substantive requirements of the ARARs are met. Offsite- actions are
subject to the full requirements of the applicable standards or regulations,
including all administrative and procedural requirements.
CHEMICAL-SMJCLFIC ARARs
Chemical-specific ARARs include those laws and regulations governing the
release of materials possessing certain chemical or physical characteristics,
or containing specified chemical compounds. These requirements generally set
health or risk-based concentration limits or discharge limitations in various
environmental media for specific hazardous substances. Examples include
drinking water standards, and ambient air quality standards.
IDCATTON-SPECIFIC ARARS
Location-specific ARARs are design requirements or activity restrictions based
on the geographical or physical position of the site and its surrounding area.
Examples include areas in a flood plain, a wetland, or a historic site.
ACTION—SPECIFIC ARARs
Action-specific ARARs are technology-based and establish performance, design,
or other similar action-specific controls or regulations on activities related
to the management of hazardous substances or pollutants. An example includes
RCRA incineration regulations.
The charts following on pages 19 - 24 summarize ARARs for this site. The
charts following on pages 25 to 29 list TBC's for this site.
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19
QBflCAL SPECIFIC AVRS
Standard, Racj-rinaiBt,
Criteria, or Limitation
FEDERAL:
Safe Clinking water Act
National Frirary Drinking
Water Standards
National Secondary Drinking
Mate* Standards
Maxmrn Cartarrinart La/el
Goals
Citation
40 U.SX. Sect. 300
40 C.F.R. Fart 141
40C.F.R. tot 143
Clean Water Act
Water Quality Criteria
Ri>. L. N>. 93-339
100 Stat. 642 (1986)
33 U.SX. Sect.
1251-1376
40 CJFJR. Fart 131
Description
Establishes health-based standards
for piriic water system (maxmm
contarrinant levels).
Establishes welfare-base standards
for public water system (secondary
naxiiunoontaninant levels).
Establishes drinking water cpality
goals set at levels of no knon or
anticipated adverse health effect.
Sets criteria for water quality
based on toxicity to aquatic
and hunan health.
Applicable/
Relevant and
Appropriate
ft/Yes
NVN3
WYes
CuinuiL
The rCLs for organic and in-
organic oontaninants are
relevant and appropriate for
water at the site since it is
a potential drinking water source.
The secondary Mis tor in-
organic oontaninants in grand
water are
gjidelires.
Proposed ld& for organic and
and inorganic oontaninants nay be
relevant and appropriate for
grand water potentially used
for drinking water.
The AJQC tor organic and in-
organic oontarrinants are
relevant and appropriate.
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2.0
OfiflCflL SPECIFIC MRS (CONINE))
Standard, Requirement,
Criteria, or Lim'tation
STATE;
Michigan Water Resources
Comrissim Act
toter quality Standard
Citation
R323.1D65
fd MS
Part4
Rule 55
Rule 57
Rule 82
Rule 90
Rule 96
Description
/tolicable/
Relevant and
Appropriate
Establishes water qjallty re-
qjirenents applicable to all
surface waters of Michigan
which protect public health
and environiBit.
Regjlates taste and orbr
producing substances
Yes/Tb
NtfYes
Prohibits within waters
of the state toxic substances at specific
levels injurious to various water uses Yes/No
Defines mixing Tones
Specifies water quality standards
Specifies coiplianoe with water
qjality standards
WYes
Yes/It)
Yes/tto
CoillBlt
Gjidelf/ies for allowable
levels of toxic organic
and inorganic oonpands
in surface water after a
discharge is nrixsd with a
receiving stnean.
CitiTen cotplaint of ortr
fron Little Bar Cneek
Variajs pollutants in
Little flaar Crtsk fond in
excess of levels in Rile obe
to influx of contaninated
Relevant to consiobr in
reoeiving strean belcw effluent
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21
UEATIOWPECIFIC rms
Standard, Requirement,
Criteria, or Limitation
FEDERAL:
Resource Conservation and
Recovery Act (as aiended)
Location Standards
Fish and Wildlife Coordination
Act
Floodplain ttragenent
Executive Order
Citation
42 U.SX. 6901
40C.F.R. 254.18(b)
16 U.SX. 661-666
Executive Oxter 11988
40 CJFJR. 6.302
Uplands Protection
Executive Oxter 11990
40 C.F.R. 6, Appendix A
Description
Applicable/
Relevant and
Appropriate
A TSD facility nust be designed,
constructed, operated, and main-
tained to avoid washout.
NVYes
Actions that are to occur in
floodplain should avoid adverse
effects, miniirize potential ham),
restore and preserve natural and
beneficial value.
Requires that Em oordrt activities
to avoid, to the extent possible,
the Ion}- and short-term adverse
irpacts associated with the de-
destruction or modification of
wetlands.
Yes/to
Yes/to
Qjinut
tatential nanedies alternatives
within the 100-year floodplain.
RojjiraiHt is relevant and
appropriate.
Raredial actions are to prevent
incursion of contaninated ground
water onto forested floodplain.
Ranedial actions to irpact site,
directly by stopping incursion
of ocntairinated gnound water
into wetlands area associated
with Little Bear Creek.
-------
LOCATION-SPECIFIC ARARS (CONIINED)
Standard, Reqjirerent,
Oriteria, or Limitation
STAJE
Upland Protection Act
Endangered Species Act
Thomas J. Anderson, Gordon
Rxkvell ErvironrBtal
Protectioi Pet
Water Resources Act
Water Resources Act
Soil/Sedimentation
Control Act
Inland Lakes/Streams Act
Air tolluticn Act
Citation
PA 203, R281.701
/tt HB, R299.1021-
R299.1028
At 127.P.A. 197D
323.6
Sec. 6(a)
Act 245.
Part 21
A* 347
Act 346
Act 348
Description
Provides for preservation,
managaiEnt, protection, and use
of wetlanofc by prohibiting
certain activities, reqirirlng a
permit to alter wetlands, and
irpsing penalties and fees
for violation of the act.
Provides for protection of
endangered or threatened fish,
wildlife, and plant species.
/tt is to protect air, water,
and other resources and the
pj)lic trust in State from
pollution, tpainrmt, and
destruction.
Unlawful to discharge to waters of
State injurious substances
Establishes NttS discharge
standards for effluent to stream
Plan to control erosion within
500 feet of lake or stream
Involves acts vJrich construct,
remove, or place structures on bottomland
Involves sources of air contaminants
Applicable/
Relevant and
Appropriate
Yes/It)
to/to
Yes/to
Yes/fa
WYes
rtyYes
to/Yes
Cuiliui
Ranedial actions to impact site
directly by stopping incursion
of contain'rated grcunctater into
wetlands area associated with
Little Bear Greek.
ND State endangered or threatened
species were identified in or near
site.
Act directly appl icable to envi ron-
nental degradation found at the site.
Carpi iance with this ARAR decronstrata
via carpi iance with Act 245, fert 21
Carpi iance with teonical reqjirarents
of tfiis Part necessary;
not for adm'rristrative conditions for
onsite rsredial action
(Sate as above)
(Sane as above)
(Sane as above)
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23
CTT/SIOW/CCRDOVA
SuMWY CF OWN) UVTCR FMMNGS and /KflRs
Compound
Volatile frames
Acetone
Benzene
ChlorobenzBne
Chloroethane
1,1-dlchloroethenB
UKlichloroethane
1,2-dichlonoethane
1,2-didiloroethane (total)
^t%^en^ Chloride
Toluene
Trichlorosthene
Viryl Chloride
Sanl-Volatlle Orgnics
AnlHre
Bis(2-€thylhesyl)phtha1ate
Benzole Acid
Baizyl Alcohol
Butyl Baizyl phthalate
4-Chloroaniline
2-Chlorcphenol
N-NJtrosodlphen/lairine
Corcentration
Detected
1600
3800
110
34
7900
6300
110000
140
2300
38000
110
130000
6003
91
47000
3000
2
1200
2100
1200
19
Drinking t&er
Standard ttonmm
Contaminant Level
ML
Excess Lifetime
Groer Risk -10*
Exposure Fran
Ingestion Residential
Exposure
7
5
5
2
0.05
0.4
4.7
3.2
0.02
51
ItavCancinpgaiic
Risk Reference
Dose Concentration
Hidiest Risk
Age QKMP. 0-6 frs
1000
270
1200
3000
7.1
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24
SW«Y OF GROIN) WWER FINMNSS «J /WRs
(ug/1, ppb)
. Excess Lifeline Wn-Carcinogmic
Drinking toter Canoer Risk - Mr6 Risk Reference
ftwrnm aandand fbdmun Exposure Fran Dose Oonoertration
Conoatration Ccntairinart Level Ingesticn ftesidatial Highest Risk
Oanxmd Detected fO. _ Exposure flga Qnoup, 0€ frs
testicides
Expopdde 0.49 - CUM
4.4-OD 0.13 -
Inorganics
Arsenic 92 50 0.02
Bariun 1680 1000 - 500
Copper 119 370
Chramun 7^ 90 - 50
Leai 101 50 - 14
Seleniun 2.4 10 - 30
Silver 1070 50 - - X
Zinc 2230 2100
Qyanide 616 200
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25
(TBC) WIERMLS
PRGPQSH) NOTION. PRIMARY CRIMING tflTBl REflJLATICNS
Contaminants
INWMCS
Asbestos
Bariun
Cadniun
QironJun
ttrcury
Nitrate
Nitrate
Seleniun
Drinking Water
Health Effects
Benign tutors
Circulatory systan
effects
Kidney effects
Gastrointestinal
effects
Kidney effects
fbtharoglobinania
('blue baby" syndrcne)
ftrtharcglobinania
("blue baty" syrdrtne)
Naunological effects
Proposed Current
HUG ML
(mg/L) (mgA.)
7 million
fibers/liter
5
OJB5
0.1
0.02
10
1
OU£
-
1
0.01
0.05
0.002
10
-
ojn
Proposed
m
(mg/L)
7 million
fibers/liter
5
0.005
0.1
OJS2
10
1
OJB
Sources
Qoological, asbestos
oarant pipe
Geological
Geological, mining
and smelting
Geological
Used In manufacture
of paint, paper, vinyl
chloride; used In
fungicides; geological
Fertilizer, savage,
feedlots
Fertilizer, savage,
feedlots
Geological, mining
Analytical
Methods2
m
(FM;
DV\A;ICP
CFM;
ICP
(FAA;
DWA;ICP
rcv^cv
fCR;IC;ISE
/CR^VR
^jIC
flCRjfCR
(FM^m
BAT3
CVF^F;
Qf&
IE;LS;
RO
IE;RO;
C/Fd^
PVFjIE;
LSjRO
GflCi^
(VF^O;
FAC
lE^O
lEdtt
MdJS,
(VF^O
VOLATILE (HMCS(Solvents)
cis-l,2-0ichloroe- Nervous systen,
tnylene liver, kidney
00)7
0.07
Extraction solvent,
dyes, perfuiBS,
phanrBceuticals, laoopers
502.1;502.2; PTA;GflC
508.1;524.1;521.2
-------
26
TO-BE-CONSIDERED (1BC) WIERMLS
PROPOSED NOTICWL FRWRY DRINONG MCTER REFLATIONS (CCNTINUH))
Contani nants
INRGWCS
1,2-Didiloropropane
Ethylbenzene
toujilorcbenaene
O-Dichlorcbenaene
Styrene
Tetrachloroethylene
Toluene
trans-1,2-
Dichloroathylene
pylons
Proposed Current Proposed
Drinking Water MUG fa ML
Health Effects (ng/i) (npA) (nq/L)
Liver toxin, lung
and kidney effects
Liver, kidney effects
Respiratory, nervous
systen, liver,
kidney effects
fervous systan,
lung, liver, kidney effects
Possible cancer,
liver, central nervous
systen effects
Probable cancer
tervous systen,
lung, liver effects
Nervous systen,
liver, kidney effects
Central nervous
system effects
0 0.005
0.7 - 0.7
0.1 - 0.1
0.6 - 0.6
OAU1 - QJJ&JO.l
0 - 0.005
2 2
0.1 - 0.1
10 - 10
Aialytical
Sources rfethods2 BAT3
Pesticide, solvent (Aialytical Methods and BAT at
the sane for all volatile
organics)
rbnrfacture of styrene
Solvent, pesticide
Industrial solvent,
pesticide
1 tturufacture of
polystyrene plastic
Dry cleaning solvent
Solvent, gasoline additive
Extraction solvent, dyes,
perfunes, Pharmaceuticals,
lacqjers
Solvent; used to manufacture
paints, dyes, actesives,
detergents; fuel additive
-------
27
TME-CCNSIDERB) (TBC) MATERIALS
FRQPQGED NOTION*. FRJWY DRINOfG WVTHt REQIAT106 (CCNTINJB))
Contaninants
PESnCDESABfilCIDES
Alachlor
Aldicarb
Aldicarb sulfoxide
Aldicarb sulflone
Atrazine
Cartofuran
Chlordane
BCRGANICS
Dibrcmcchloropropane
(KP)
w
Ethylene dibrtnride
Proposed Qiment Proposed
Drinking Water HUG KI MCL
Health Effects (ng/L) (mg/L) (ng/L)
/RBs
Probable cancer 0
fervous systen toddty 0.01
Nervous systen toddty 0.01
tervous systsn toddty 0.04
Narvcus systsn, 0.003
liver, heart effects
Nervous systsn, 0.04
reproductive effects
fervous systsn, 0
liver effects
Probable cancer 0
Liver, kidney effects 0.07
Probable cancer 0
0.002
0.01
OJE
OM
Qjcm
0.04
0.02
OJCtXZ
0.1 OJOf
OJB005
Analytical
Sources tethods2
Herbidde
Pestidde, herbidde,
restricted in seme areas
Pestidde, herbidde,
restricted in sore areas
Pestidde, herbidde,
restricted in sore areas
.Herbicide
Pestidde, herbidde
Pestidde, herbidde,
nost uses barred in 1990
Pestidde, cancelled
in 1977
ferbidde
Gasoline additive
505^07
531.1
531.1
531.1
505^07
531.1
505^03
504
515.1
504
BAT3
GAC
GAC
GAC
GAC
GAC
GAC
GAC
GAC
GAC
GAC
soil fum'gant, solvent, most
pesticide uses restricted in 1991
-------
28
TOff-CONSIDERB) (TBC) WIERMLS
PRQRBED NOTION. FR1WRY NINONS WTER RBaiATlONS (CQNTINJB))
Gartani rents
Hqptachlor
teptachlor epoxide
Lindane
ffettogchlor
PCBs
Pertachlorophenol
Toxaphene
2,4,5-IP (Sllvex)
Proposed
Drinking Mater fCLG
Health Effects (mg/L)
Probable cancer
Prcbable canoer
Neurological, liver,
kidiey effects
Central nervous
system effects
Probable cancer,
reproductive effects
Organ central nervous
system, fetal effects
Probable cancer
Liver, ki*ey effects
0
0
0.0002
0.4
0
0.2
0
0.05
Ojrrent Proposed
ML Ml
(ng/L) (mg/L)
0.0X4
0.0002
0.004 0.0002
0.1 0.4
- . 0.0005
0.2
0.006 0.006
0.01 0.05
Sources
Insecticide,
ircst uses restricted in 1963
Insecticide,
rrost uses restricted in 1983
/talytical
fethods2
505;508
905;508
Insecticide to control fleas, 506^03
lice, tides, sore uses restricted
in 1983
Insecticide
vfery persistent, transformers,
capacitors; production banned
in 1977
Wood preservative;
non-wood uses barred in 1987
Pesticide, herbicide,
most use cancelled in 1977
Herbicide, cancelled in 1933
505;508
506;
508(screen mly);
5084
515.1
505
515.1
B«r3
GAC
GAC
GAC
GAC
GAC
GAC
GAC
GAC
ORIN
-------
29
proposes a dual MCLG/MCL for styrene.
single MCLG and MCL will be set.
After public raiment, a
2Analytical Methods key:
TEH -Transmission Electron Microscopy
GFAA -Graphite Furnace Atonic /Absorption
DAAA -Direct Aspiration Atomic /bsorption
ICP -Inductively Coupled Plasma
fCV -Manual Cold Vapor
ACV -Automated Cold Vapor
GHAA -Gaseous Hydride Atomic Absorption
MCR -Manual Caomium Reduction
ACR -Automated Cadnium Reduction
AW -Automated tfydrazine Reduction
ISE -Ion Selective Electrode
1C -Ion Chromatography
SP -Spectrophotmetric
Analytical Methods Numbers to EPA methods
.%est Available Technology (BAT) key:
AA -Activated Alumina
C/F -Coagulation/Filtration
CC -Corrosion Control
DF -Direct Filtration
DMF -Dlatcmite Filtration
PAC -Powered Activated Carton
GAC -Granular Activated Carbon
IE -Ion Exchange
LS -Lime Softening
RO -Reverse Osmosis
PTA -Packed Tower Aeration
PAP -Polymer Addition Practices
^Treatment technique requiranent limits
the amount of the chemical which is used
to treat drinking water.
-------
30
OGMPARATTV AN^SIS OF
1.
CRITERION:
OVERATJL PROTECTION OF HUMAN HFAT.TTT
AND THE ENVIRONMEN
Alternative 1
Alternative 2
(Groundwater Extraction,
Oorganics Pretreatment,
Filtration, Biological
Treatment, Stream Dishcarge)
Alternative 3
(Slurry wall with
Groundwater Extraction
Filtration, Biological
Treatment, Stream Discharge)
Alternative 4
(Groundwater Extraction,
Organics Pretreatroent,
Filtration, POIW
Discharge)
Alternative 5
(Slurry wall with
Groundwater Extraction,
Organics Pretreatment,
Filtration, POTW
As we have seen, signs warning of contaminated
water have been placed in Little Bear Creek. A
risk has also been identified with air
inhalation at points within the stream's valley,
and a chloroform level in Little Bear creek
exceeded the appropriate ambient water criterion
by a factor of nearly two-fold. Additionally,
levels of benzene, vinyl chloride, and 1,2-
dichloroethane exceed drinking water criteria
within Little Rpar Creek. Vinyl chloride levels
also exceed by over a sixteen-fold a Michigan
criterion on the presence of toxic substances at
levels which are or may become injurious to the
public health, safety, or welfare. Benzene
levels in Little Bear Creek exceed U.S. EPA
ambient water quality criteria for carcinogenic
protection of ingestion of water and organisms
by nearly forty-fold. Such conditions are not
protective of human health and the environment.
Consequently, the No-Action alternative is not
appropriate for this site.
This alternative will prevent contaminated
discharge from entering the Little Bear Creek
system to the extent necessary to adequately
protect human health and the environment.
This alternative will prevent contaminated
groundwater discharge from entering the Little
Bear Creek system to the extent necessary
to adequately protect human health and the
envir
nt.
This alternative will prevent contaminated
groundwater discharge from entering the
Little P*>«r creek system to the extent necessary
to adequately protect human health and the
environment.
This alternative will prevent
contaminated groundwater discharge from
entering the Little Bear Creek system to the
extent necessary to adequately protect human
health and the environment.
-------
31
Alternative 6
(Trench Intercept, No
Treatment, POIW Discharge)
Alternative 1
Alternative 2
Alternative 3
Alternative 4
Alternative 5
Alternative 6
Alternative 1
Alternative 2
Alternative 3
This alternative will prevent
contaminated groundwater discharge from
entering the Little Bear Creek system to the .
extent necessary to adequately protect human
health and the environment.
2. OCMPr.TANCE WITH ARARs
Alternative 1 will not comply
with federal/state ARARs.
This alternative complies with
federal/state ARARs.
This alternative complies with
federal/state ARARs.
This alternative complies with
federal/state ARARs, if no bypass
condition occurs.
This alternative complies with
federal/state ARARs, if no bypass
condition occurs.
Alternative 6 does not comply
with federal/state treatment ARARs as originally
proposed. For comparison purposes, U.S. EPA
j»g.«?nnioH treatment was performed. Alternative 6
may not meet requirement for protection of
wetlands and flcodplains.
3. IONS-TERM
AND PERMANENCE
Taking no action will result in significant
risk remaining from contaminated groundwater
entering the stream and posing problems of
surface water contact and air inhalation.
It is expected that several years of groundwater
extraction and treatment may leave residual
contamination in groundwater. Dealing with such
residuals will be an objective of the full site
feasibility study.
Sa**=» as Alternative 2, however, the conplex
nature of the groundwater contaminants may pose
a long-term threat to impermeable nature of
slurry wall.
-------
32
Alternative 4
Alternative 5
Alternative 6
Alternative 1
Alternative 2
Alternative 3
Alternative 4
Alternative 5
Alternative 6
Sane as Alternative 2; however, potential for
POttW bypass exists.
Sane as Alternative 3; however, potential for .
POIW bypass exists.
Same as Alternative 2, but potential loss of
underdrain permeability due to biological
growths over time and lack of containment of
contaminated groundwater exists. Greater
disruption of habitat in stream floodplain is
also possible.
Maintenance of the trench so as to promote
continued high rates of infiltration over time
are not explored by the stated alternative. It
can be theorized that biological fouling of the
trench may be possible. If so, the rate of
infiltration into the trench will be reduced.
If infiltration rates were reduced sufficiently,
the trench would not serve as an effective means
of intercepting contaminated groundwater, and
pollution of Little Bear Greek would resume.
4.
No
OF TDXlLU/nf.
OR VOIIJME THROUGH TREATMENT
would be treated.
Approximately 210 million gallons per year of
contaminated groundwater would be extracted and
treated, and up to 165,000 pounds of total
organic contaminants would be removed from
groundwater over a year's time. Approximately
400-500 tons per year of residual solids from
filtration/wastewater treatment may be created.
Approximately 79 million gallons per year of
contaminated groundwater would be extracted and
treated, and up to 80,000 pounds of total
organic contaminants would be removed from
groundwater over a year's time. Some 200-300
tons per year of residual solids from
filtration/wastewater treatment may be created.
Same as Alternative 2, above.
Same as Alternative 3, above.
Approximately 210 million gallons of groundwater
would be extracted and treated per year.
-------
33
5. SHDRP-TEPM
Alternative 1
Alternative 2
Alternative 3
Alternative 4
If no action is taken, significant risk will
remain £rcui contaminated groundwater entering
the stream and peeing problems of surface water
degradation, resource impairment, and air
inhalation.
Alternative 2 would take about 18-20 months for
Installation completion. Construction is
expected to result in srry minimal disturbance
to the community. A program of health and
safety training and usage of protective gear is
expected for workers. Environmental impacts are
expected to be slight; dust control measures
would likely be necessary, contaminated soil
cuttings would be dispospd according to RCRA.
Groundwater extraction may result in reduced
stream flow, notably in the unnamed tributary.
Alternative 3 would take about 19-21 months for
installation completion. Usage of a slurry wall
will increase disturbance to the community due
to increased volatile air emissions during
excavation. Temporary residential relocation
may be required. More disturbance to
vegetation/ potential habitat is likely due to
slurry wall excavation. Such excavation would
also present further health/safety factors for
which workers must be made aware. On the other
hand, employment of a slurry wall could likely
reduce sludges created by wastewater treatment.
However, Alternative 3 also has drawbacks. In
arranging access, it is easier to secure a few
well installation points as opposed to a
continuous strip of land some 1000 ' long.
Moreover, most of this strip of land would be
behind residential properly along Central Road.
Possible air emissions may be created in
excavating for the slurry wall. Given that one
would be working in a zone of contaminated soils
and groundwater, one should consider the
possible effects on nearby residents as well as
workers. Air emissions from well boreholes
would appear to pose less of a problem to
residents.
Alternative 4 would take about 16-18 months for
installation completion. Other short-term
effectiveness features are as in Alternative 2,
above.
-------
34
Alternative 5
Alternative 6
Alternative 1
Alternative 2
Alternative 3
Alternative 5 would take about 18-20 months for
installation completion. other short-term
effectiveness features are as in Alternative 3,
above.
Sane as Alternative 3, but habitat disturbance
would be more pronounced and no reduction in
residuals generated would occur.
6.
Not applicable to a no-action alternative
The groundwater extraction and treatment
facilities are readily constructed. While pilot
testing is likely needed to yield best
performance, implementation of this alternative
would not make any future remedial actions
significantly more difficult to undertake.
Monitoring effectiveness can be done through
groundwater - surface water sampling and
analysis; biological monitoring may be needed to
help judge performance and stream recovery. One
type of pretreatment for organics that could be
utilized is somewhat innovative; (i.e.
ultraviolet oxidation) all other technologies
envisioned are conventional. This will require
access arrangements for piping, as will all
other Alternatives except Alternative 1.
Back in the days of Ott Chemical operation, some
water supply and purge wells had to be abandoned
or suffered greatly curtailed pumping capacity
due to fouling. Such fouling may have been
caused by the pollutants in the groundwater.
However, establishing a regularly - scheduled
program of well maintenance and downtime would
help to avoid such problems. The extraction
wells envisioned by this alternative would
presumably be of 8 * * —10 * ' diameter.
Moreover, if a well became inoperable during
maintenance, the remaining wells could be pumped
harder to try to extend their zones of coverage.
Alternative 3 presents much the same components
of implementability as Alternative 2. However,
usage of a slurry wall would pose a more
difficult construction task than Alternative 2,
and arranging access for a 1000' continuous
strip of land would be more difficult.
-------
35
Alternative 4
Alternative 5
Alternative 6
Alternative 1
Also, slurry wall integrity, once in place,
becomes an issue. Given the complex nature of
the overall contaminant blend in the
grcundwater, the materials in the groundwater '
could pose some possibility of attack or
breakthrough of the slurry wall.
Alternative 4 presents ouch the same components
of implementability as Alternative 2.
However, physical checking of pipeline integrity
would need to be enhanced. Also, institutional
considerations may play a role in
implementability. Negotiation over capital
share with the POIW would prove necessary.
However, Alternatives 4 and 5 both pose
drawbacks as well. As RI fieldwork was
proceeding in 1988, -local newspapers carried
accounts of by-passing of the Muskegon County
FOTW. Moreover, it is proposed that this POIW
undergo a large expansion of nearly 10 mgd.
However, the Muskegon County Wastewater Division
is not receptive to dedicating any of this
planned expansion to accept flows from the
Ott/Story/Oordova site. Instead, separate
financial commitment for additional capacity may
be required before this remedy can be
implemented.
Alternative 5 presents much the some component
of implementability as Alternative 3 and 4
combined.
Same as Alternative 3; however the need to
provide for trench dewatering during
struction adds a further factor.
7. COST
(NOTE - Cost estimates are order-of-magnitude
level with an expected accuracy of plus 50
percent to minus 30 percent. All estimates and
present worth calculations are rounded to no
more than three significant figures.)
Capital Costs $0
Operation/Maintenance $0
(over 5 years)
Total Present Worth $0
-------
36
Alternative 2 . Capital Costs $ 5,030,000
Operation/Maintenance $ 7,000,000
Total Present Worth $11,700,000
Alternative 3 Capital Costs $5,620,000
Operation/Maintenance $4 , 090 , 000
Total Present Worth $9,500,000
Alternative 4 Capital Costs $3,140,000
Operation/Maintenance $2,082,000
Total Present Worth $8,840,000
Alternative 5 Capital Costs $3,600,000
Cperation/Maintenanoe $3,750,000
Total Present Worth $7,380,000
Alternative 6 Capital Costs $ 5,500,000
Cperation/Maintenanoe $ 7,700,000
Total Present Worth $12,200,000
STATE ACX-'K CHANCE and OCMONITY
The MENR has expressed concern to U.S. EPA over the "severe surface water
degradation" in Little Pear Creek "below the point where the contaminated
groundwater enters the stream.11 MCNR has urged U.S. EPA to act "as quickly as
possible" to stop the contamination from this site from entering the Little
Bear Creek system. To the best of U.S. EPA's knowledge and belief, Michigan
favors Alternative 2.
At the August 16, 1989 public meeting, no area resident expressed disapproval
of action to control surface water contamination. Several residents commented
that U.S. EPA should move aggressively not only on this aspect, but also on
the issue of remediation of contaminated soils.
These criteria will be considered in more detail in the responsiveness summary
commentary of this report.
9. THE
Based upon consideration of the requirements of CERdA, the detailed
evaluation of the alternatives, and public comments, both EPA and the State of
Michigan have ctetyntnTigd that Alternative 2 fGroundwatPT Extraction. Organics
Removal. Filtration. Biological Treatopnt. Stream Dishf^aw*) is the most
appropriate remedy (first operable unit) for the Ott/Story/Cordova Site in
North Muskegon, Michigan.
A series of extraction wells in the vicinity of Little Bear Creek and its
unnamed tributary will intercept approximately four hundred gallons per
minuate of contaminated groundwater from entering these surface water bodies
prior to treatment. Contaminants in the groundwater will be addressed through
-------
37
first removing organics by physical - chemical means, employing filtration for
subsequent organic contaminant, suspended solids, and color removal, and then
utilizing biological treatment to bring about further reduction in degradable
organics. Waters thus treated will then be discharged into Little Bear Creek,
or the North Branch of the Muskegon River. Effluent quality will be dictated
by values as established by the NFCES program administered by the Michigan
Department of Natural Resources. As a result of engineering undertaken in the
Remedial Design and construction process, some changes may occur in certain
remedy elements.
The response objectives for this operable unit are to intercept and contain
contaminated groundwater within the unconf ined groundwater system, eliminate
potential surface water and air exposure routes by preventing contaminated
groundwater discharge into Little Bear Creek and its unnamed tributary, and to
ensure that this operable unit is fundamentally compatible with future
remedial actions at the Ott/Story/Cordova site. In determining an acceptable
stream effluent, the applicable or relevant and appropriate requirement
(ARARs) of environmental laws were reviewed. These values are presented on
page 41 in this text as "Michigan Limits on Stream Discharge".
The intrusion of contaminated groundwater into Little Bear Creek and its
unnamed tributary has resulted in the degradation of portions of those bodies
of water. Undertaking the selected remedy will bring about a recovery in
stream quality, and will also reduce risk associated with contact with surface
water and inhalation of volatile organics.
-------
38
COST SUtWRY FOR THE SELECTED REMEDY
(1 = 5 percent)
COST COMPONENT
FOUR EXTRACTION WELLS
UV-OXIDATION
CARBON ADSORPTION
ACTIVATED SLUDGE **
FILTRATION .
STREAM DISCHARGE
MISCELLANEOUS
TOTAL CAPITAL COSTS
YEAR COST
INCURRED
0
1 thru 5
0
1 thru 5
0
1
2
3
4
5
0
1
2
3
4
5
0
1 thru 5
0
1 thru 5
0
1 thru 5
ANNUAL OPERATION & MAINTENANCE
PRESENT WORTH
CAPITAL
COST($)
(TABLE)
470,000
1,180,000
650,000
1,190,000
120,000
200,000
1,220,000
$5,030,000
YEAR1
YEAR2
YEAR3
YEAR4
YEARS
ANNUAL
OSM($)
(TABLE>
32,000
233,000
210,000
190,000
171,000
154,000
187,000
180,000
173,000
167,000
161,000
4,000
0
726,000
$1,605,000
$1,575,000
$1,548,000
$1,523,000
$1,500,000
PRESENT
WORTH
FACTOR
1.0000
4.3295
1.0000-
4.3295
1.0000
0.9524
0.9070
0.8638
0.8227
0.7835
1.0000
0.9524
0.9070
0.8638
0.8227
0.7835
1.0000
4.3295
1.0000.
4.3295
1.0000
4.3295
PRESENT
WORTH ($)
470,000
139,000
1,180,000
1,831,000
650,000
222,000
190,000
164,000
141,000
121,000
1,190,000
178,000
163,000
149,000
137,000
126,000
120,000
17,000
200,000
0
1,220,000
3,143,000
$11,751,000
** Costs for activated sludge include the costs associated with
residuals managenent (sludge dewatering and disposal).
-------
39
10. STATUTORY. DETERMDlflTIONS
PROTECTION OF HUMAN HEAUH AND THE ENVIRONMENT:
Surface water samples collected from Little Bear Creek and its unnamed
tributary were found to be contaminated with the coqpounds whose source was
seeps of upwelling ground water. Signs warning of contaminated water have
been posted in the stream bed by Muskegon County Health Department upon
recommendation of the State of Michigan. Entry of contaminated groundwater
into the streams also presents an air inhalation problem, due to the volatile
nature of several of the contaminants. Residents near Little P^gr Creek and
the unnamed tributary are exposed to excess lifetime cancer risks ranging from
1 x 1CT6 to 1 x 10~4 for high inhalation exposures, and are being deprived of
full usage opportunity of a water resource.
Hie selected remedy protects human health and the environment through
interception of contaminated groundwater in the vicinity of Little E*»ar Creek
and subsequent treatment of organics removal, filtration, and biological
treatment. Such treatment will eliminate the major source of hazardous
substance contamination of the Little Bear Creek system in the vicinity of the
Ott/Story/Cordova site. It is believed that any short-term threats associated
with the selected remedy can be readily controlled. Design of the selected
remedy will be such that a cross-media problem (e.g. air emissions that could
result from volatile contaminants in groundwater) will be controlled.
POST—
**>'t* '.ELM.'!
The selected remedy is cost-effective because it has been determined to
provide overall effectiveness proportional to its costs, the net present worth
value being $11,750,000. The selected remedy effectively reduces the hazards
posed by the site contaminants. The cost-efficiency of the selected remedy
will be furthered by engineering conducted during remedial design. While
apparent costs of POTW discharge options are less than the selected remedy,
the selected remedy avoids the uncertainty of POIW capacity and related
capital assessments for this site, as well as the future user fee and bypass
questions.
CCMPT.TANCE WITH APPLICA
APPROPRIATE REQU.L**» fARARs)
The selected remedy of groundwater extraction, organics removal, filtration,
biological treatment, and stream discharge will attain all ARARs pertinent to
effluent discharges and stream standards. This operable unit does not address
the final remediation of groundwater restoration, which will be addressed as
site remediation proceeds through the RI/FS process. ARARs pertaining to
groundwater restoration are not arklressed in this operable unit, but will be
considered in the overall site Feasibility Study. Key ARARs for this project
are effluent and stream quality limitations provided by the State of Michigan.
These are given below:
-------
40
MICHIGAN LIMITS ON STREAM DISCHARGE (Act 245, Fart 21; Rule 57)
N03ELS for parameters to be treated and discharged fron the Ott/Story/Cordova Chemical Conpany site, Muskegon County, Michigan NPOES
termit 0MI0048145 - Proposed alternative discharge sites located on Little Bear Creek or H Channel Mjskegon River at discharge rates of
either 0.57 or 2.47 MGD.
UATER QUALITY BASED EFFLUENT LIMITS
ESTIMATED (30-DAY AVERAGE LIMITS)
GROUNEWATER BAT* ACUTE RULE 57(2) OPTION* OPTION* OPTION* OPTION*
CONCENTRATION LIMITS VALUES VALUES 1234
PARAMETERS (ug/1) (ug/1) (ug/1)
vinyl chloride **
1,1-dichlorethane
1,1-dichloroethene **
benzene **
toluene
chloroform **
methyl ene chloride **
1,2-dichloroethane **
chloroebenzene
MIBK (4-aethyl ,2-hexanone)
acetone (2-propanone)
benzyl alcohol
0-cresol (4-methyl phenol)
2-chlorophenol
n-methyl aniline
2-ethyl aniline
4-chloroaniline
tetraethyl urea
camphor
benzole acid
tetrahydrofuran
bis (2-ethyl hexyl)
phthalate **
12000 3
1700
250 2
350 5
803 5
500
500
250000 10
50
50
600
200
50
50
4500
2000
300
50
2500
300
200
50
INSUFFICIENT
3000
5300
4800'
3600
2640
12700
3200
(ug/i)
3.1
Comnent* (ug/1)
TLSC BAT
(ug/1)
BAT
(ug/l) (ug/1)
BAT
BAT
INFORMATION
2.6
60
100
43
59
560
71
52000 1155
2000
140
440
500
44
3
10
CRV BAT
TLSC BAT
ACV 225
CRV BAT
ACV BAT
CRV 1260
ACV 160
ACV 2599
TLSC 1125
ACV 99
ACV 7
ACV 22
BAT
BAT
129
BAT
BAT
721
91
1487
644
57
4
13
BAT
BAT
10327
BAT
BAT
BAT
7332
119280
51636
4544
310
1033
BAT
BAT
2450
BAT
BAT
BAT
1739
28296
12249
1078
73
245
INSUFFICIENT INFORMATION
1234
240
7200
9368
5000
4520
27
5
533
60
208
11
100
ACV 61
ACV 11
ACV 1199
ACV 135
ACV 468
ACV 25
ACV BAT
35
6
928
77
268
14
BAT
2789
516
27788
6196
21481
1136
BAT
661
122
13059
1471
5096
269
• BAT
-------
41
PARAMETERS
ESTIMATED
GROUNDWATER
CONCENTRATION
(m/D
BAT*
LIMITS
(ug/D
MICHIGAN LIMITS ON STREAM DISCHARGE (Act 245, fert 21; Rale 57)
ACUTE
VALUES
(ug/1)
RULE 57(2)
VALUES
(ug/1)
OPTION*
1
Garment* (ug/1)
(30-DAY AVERAGE LIMITS)
OPTION* OPTION* OPTION*
234
(ug/1) (ug/1)
arsenic
cadniim
chroniun
copper
cyanide A
lead
nickel
seleniun
zinc
30
60
20
20
1500
184
0.7
93
40
4
10
148
. 22
177
241
0.9
121
51
5
11
191
29
229
197
0.7
99
42
4
10
157
24
189
4863
18
2435
977
105
130
3666
585
4435
* Option 1 = 0.57 MGD discharge to Little Bear Creek with a 95% exceedance flow of 1.1 cfs.
Option 2 = 2.47 MGD discharge to Little Bear Creek with a 95% exceedance flow of 1.1 cfs.
Option 3 = 0.57 MGD discharge to N. Channel of the Mjskegon River with a 95% exceedance flow of 360 cfs.
Option 4 = 2.47 MGD discharge to N. Channel of the Muskegon River with a 95% exceedance flow of 360 cfs.
BAT = BEST AVAILABLE TREATMENT
CRV = CANCER RISK VALUE
ACV = AQUATIC CffiONIC VALUE
TLSC = TERRESTRIAL LIFE CYCLE SAFE VALUE
1259
4.7
631
255
27
37
956
151
1155
**
CARCINOGEN
-------
UTILIZATION OF PERMANENT SOIITTIONS
TO 1HE MAXIMUM EXTENT
42
U.S. EPA and the State of Michigan have determined that the selected remedy
represents the maximum extent to which permanent solutions and treatment
technologies can be utilized in a cost-effective manner for the operable unit
at the Ott/Story/Oordova site, of those alternatives that are protective of
human health and the environment and comply with ARARs. U.S. EPA and the
State have determined that this selected remedy provides the best balance of
trade offs in terms of long-term effectiveness and performance, reduction in
toxicity, inability, or volume achieved through treatment, short-term
effectiveness, implementability, and cost, considering the statutory
preference for treatment as a principal element and considering State and
community acceptance.
The selected remedy will significantly reduce the hazards now posed by the
entry of contaminated groundwaters into Little Bear Creek and its unnamed
tributary. The selected remedy will treat this contaminated groundwater
through removal of organics and solids such that the resultant effluent can be
discharged into Little Bear Creek and meet substantive requirements of the
NPDES system as administered by the State of Michigan.
The selected remedy provides for less disruption and requires less time to
implement than do options involving a slurry wall or trench.
FOR 'iVHATyFTn* AS A
By intercepting and treating contaminated groundwater prior to its entry into
surface water streams, the selected remedy addresses one of the principal
threats posed by the site through the use of treatment technologies.
As noted previously in discussion of Alternative 1 (No-Action) , Little Bear
Creek fails to meet certain relevant and appropriate water criteria due to the
influx of contaminated groundwater originating from the Ott/Story/Cordova
site. Elimination of such threat will aid in stream recovery. The treatment
process noted in the earlier discussion of Alternative 2 will aid in the
removal and destruction of various pollutants. Therefore, the statutory
preference for remedies that employ treatment as a principal element is
satisfied.
-------
OTT/STORY/CORDOVA SITE
NORTH MUSKEGON. MICHIGAN
USPOHSIVZNB88 SUMMARY
INTRODUCTION
The purpose of this responsiveness summary is to document the comments
received during the public comment period, and the response of the United
States Environmental Protection Agency (U.S. EPA) to these comments. All
of the comments summarized in this document were considered prior to U.S.
EPA's final decision. The responsiveness summary is divided into two
sections. The Site Overview and Background on Community Involvement
section provides a brief site history, and notes concerns expressed by
citizens at various points. The Summary of Public Comments Received During
The Public Comment Period and U.S. EPA Responses section summarizes citizen
oral and written comments, followed by U.S. EPA response. In some
instances, recurring comment* addressing a common subject will be grouped
according to issue, and responded to together.
SITE OVERVIEW AND BACKGROUND ON COMMUNITY INVOLVEMENT
The Ott/Story/Cordova Superfund site it a former specialty organic
chemical production facility located at the eastern end of Agard Road in
Dalton Township, Michigan. A distinctive part of the site from 1958-1977
was the usage of lagoons to accept industrial wastewaters and for a time
high strength waste "heels1 following vessel cleanout.
The Remedial Investigation (RI) noted significant pollution of
groundwater beneath and downgradient of the site. At least a portion of
this contaminated aquifer is discharging into Little Bear Creek and its
unnamed tributary, located about one-half mile southeast of the site.
While consideration must be given to restoration of a Class II aquifer and
certain site areas where soil contamination is prominent, the basic
objective of this interim action is to halt the movement of contaminated
groundwater into the Little Bear Creek system.
-------
A* noted in the Administrative Record, community involvement with the
Ott/Story/Cordova site began as far back as the 1970's. As an example,
a letter transmitted in August 1975 from the Muskegon County Health
Department relayed citizen concern over odor problems attributed to the
site. The spread of contaminated groundwater eastward from the site and
its possible effects upon residential well water supplies further
heightened community involvement. In the late 1970's, certain citizens
filed suit against a person they believed to be a former site owner. The
Administrative Record indicates that in 1981, this suit was settled, the
outcome being extension of an alternate water supply into the area. In
1982, the site was placed on the National Priorities List. In November
1987, U.S. EPA conducted a Remedial Investigation 'kick-off availability
session at the Dalton Township Hall, located near the site. Both the
Dalton Township Hall and the Walker Memorial Library in North Muskegon
have served as local information repositories throughout the Remedial
Investigation/Feasibility Study (RI/PS) process. Concerns expressed to
U.S. EPA by citizens during the RI process arei
Concern over property value and illiquidity.
A frustration of "enough study • it is time to get on with the
business of cleanup*.
On August 16, 1989, the U.S. EPA conducted an availability session and
a formal public hearing to discuss key RI findings, and to present the
Proposed Plan for remedial action, as generated by the Focused Feasibility
Study (FFS). The public comment period was initiated on August 1, 1989.
An advertisement was placed in the "Muskegon Chronicle* announcing the
beginning of the comment period, the local availability of the Proposed
Plan and FFS report, and the time and place of the availability session and
public meeting.
-------
!tY OP PUBLIC COK
SCEIVED PORING THE PUBLIC COMMENT PERIOD
ORAL COMMENTARY RECEIVED AT THE PUBLIC MEETING
COMMENT 1: Mr. Gollach, area resident, commented that he did not favor
Alternative 6 or 7, and fears that discharges routed to the
local public operated treatment works (POTW) may cause
problems with or overload that system.
RESPONSE: U.S. EPA takes careful note of these views. While routing a
discharge from the Ott/Story/Cordova (0/S/C) site to the
POTW may be physically possible, U.S. EPA believes that such
a choice imposes a burden on it to demonstrate that an
effluent leaving the 0/S/C site will not impair or interfere
with POTW performance. Given the numerous compounds
associated with the 0/S/C site, such demonstration would be
a complex undertaking. Further, to the beat of U.S. EPA's
information and belief, the Muskegon County POTW is
considering physical expansion. However, such expansion did
not include a sizeable discharge of treated groundwater from
the 0/S/C site. Hence, if such discharge from the site to
the POTW were to occur, U.S. EPA believes it would be
necessary to negotiate for an incremental share of such
expansion. For these reasons, U.S. EPA believes a stream
discharge, rather than a POTW discharge, is appropriate.
COMMENT 2s Mr. Hughes, area resident, expressed concern about
contaminated ground and expressed concern that U.S. EPA
address treatment of such ground in addition to groundwater
cleanup.
RESPONSEi U.S. EPA believes this citizen raises a valid point. The RI
conducted for the site noted several instances of
contaminated soils. U.S. EPA agrees that it is appropriate
to consider whether such areas could act as potential
-------
sources of new releases into the groundwater system. U.S.
EPA will consider this question in the Feasibility Study
(FS) now in preparation for this site, and intends to
explore its findings and recommendations with the public.
COMMENT 3: Mr. Vogel identified himself as a former resident living
nearby the site. He expressed the desire to see U.S. EPA
conduct a health study of the area, as well as undertake
groundwater cleanup.
RESPONSE: U.S. EPA will consider carefully the citizen's views on
groundwater cleanup. As to the health study, U.S. EPA notes
that when the "Superfund' statute was reauthorized, Congress
required the Agency of Toxic Substances and Disease Registry
to perform a health assessment of all NPL sites, of which
0/S/C is one. Pending determinations made within this
health assessment, ATSDR may recommend more study or medical
monitoring of a given area/population. One such outcome may
be a health study. While U.S. EPA does not perform health
assessments/studies, U.S. EPA will be pleased to make your
views known to the ATSDR representatives stationed in
Chicago.
COMMENT 4i Mr. Gollach notes that he is submitting written material to
U.S. EPA to forward to ATSDR and supports the view that a
health study be performed.
RESPONSE! As noted in the previous response, U.S. EPA will relay the
views of citizens to ATSDR as with regard to the matter of a
health study.
COMMENT 5: Mr. Weisner, former employee and current resident, expressed
concern that U.S. EPA only took soil samples to a depth of
six inches and missed site areas he believes may be high in
-------
pollutants. Mr. Veisner believes that U.S. EPA should move
aggressively to get rid of polluted soils, such as by
incineration while also treating groundwater. This citizen
identified himself as a former site worker, and recalled
spills and waste disposal in the vicinity of former site
buildings. Mr. Weisner observed that it is his belief that
some trees on the site died because of pollutants. This
citizen further noted past management may have misled
workers as to the potentially harmful effects of working
with certain site chemicals. This citizen believes U.S. EPA
should follow a similar course of action as was developed by
Uniroyal, and believes elements of that plan included
provision for incineration of polluted soil.
RESPONSE: U.S. EPA notes with care the views expressed on the
instances of spillage during times of plant operation.
U.S. EPA wishes to point out that soil sampling was not
confined to shallow samples only. Indeed, during the RI
five borings to depths of approximately 150-170 feet were
performed and instances of pollutants appearing at
substantial depth were noted. As noted in other responses,
U.S. EPA will relay to ATSDR view* expressed on health
matters. As noted in the response to Mr. Hughes, U.S. EPA
most definitely will consider the matter of contaminated
soils, and the possible need to treat or bring about
disposal of such soils. In reviewing documents concerning
this site, U.S. EPA has noted instances of the Uniroyal
discussions with the State of Michigan, and has placed
documents dated 11/27/76. 01/03/77, and 01/17/77 in to the
Administrative Record for this site. U.S. EPA also notes
with care the commenter's view* on the need to treat site
groundwater, and views on possible damage to site vegetation
caused by past site waste management practices.
-------
COMMENT 6: Mr. Gollach noted that he is aware U.S. EPA samples were
also taken at depth.
RESPONSE:
No further response is required of U.S. EPA at this time.
COMMENT 7: Ms. Kirk, counsel representing CPC, objects to the lack of a
comment period for the RI. to the insufficient time period
for review of the FFS, and the failure of U.S. EPA to allow
access to certain studies and data.
RESPONSE: Via numerous Freedom of Information Act (FOIA) requests,
U.S. EPA has received from Ms. Kirk's firm. U.S. EPA has
supplied voluminous data concerning the site. U.S. EPA
denies that it has wrongfully failed to provide access to
site data. U.S. EPA is not bound to conduct a public
comment period on the RI. U.S. EPA supplied a copy of the
RI to Ms. Kirk's firm when supplies were made available last
spring. U.S. EPA has received numerous comments and
submittals from Ms. Kirk's firm on the conduct of the RI and
other site related information. U.S. EPA has placed a
tremendous amount of such information in the Administrative
Record for this site. Further, while Ms. Kirk's firm is the
only party stating that the public comment period is
insufficient, U.S. EPA has nonetheless extended receipt of
written comment concerning the Proposed Plan.
COMMENT 8: Ms. Robblns, area resident, notes that she wishes U.S. EPA
every euccess on our cleanup efforts at 0/S/C, but regrets
that such efforts are over ten years and numerous cancer
deaths too late.
RESPONSE: In all honesty, U.S. EPA cannot make a fitting response to
this comment.
-------
COMMENT 9:
COMMENT 10:
Mr. Gollach notes a past citizens' suit to try to get a
water supply extended to the area. He states that he
disagrees with Ms. Kirk's comments.
Ms. Kirk notes in settlement of such suit her client
contributed close to a million dollars for construction of
such supply, and further notes denial of responsibility for
operating the site.
COMMENT 11:
Mr. Weisner notes he believes significant pollution took
place when Ott Chemical operated independently.
RESPONSE:
No further response is required of U.S. EPA at this time.
COMMENT 12t
Mr. Gollach believes U.S. EPA should not overlook Mr. Ott in
the final responsibility for the problem brought here.
RESPONSES
U.S. EPA will consider this comment with care.
COMMENT 13t
RESPONSE:
Mr. Pringle, a citizen living near the site, notes that at
one time Ott Chemical had a plan for deep well injection of
wastes, but never executed this plan, and this nay account
for the pollution problem that now exists.
U.S. EPA appreciates the information provided by this
citizen.
COMMENT 14t
Ms. Harrison, area resident, notes three main areas of
concern: (a) her belief that a health study is badly
needed, (b) a concern that U.S. EPA's sampling effort did
not go far enough to the south, and (c) a hope for a meeting
forum that will include more questions and answers so that
the public may better pose comments.
-------
RESPONSE: Aa noted In the response to Mr. Vogel and others, U.S. EPA
will relay citizen concerns for a health study to ATSDR.
U.S. EPA also appreciates this citizen's views on sampling
extent. The charts and graphs U.S. EPA used in discussing
key RI findings did not include all wells sampled, but
rather those that seemed of more significance. Of relevance
to this commenter's point. U.S. EPA notes a sharp
distinction between upgradient wells somewhat northwest of
the site and site wells. The upgradient wells showed a
virtual absence of pollutants; site wells in numerous cases
were heavily polluted. Ideally, one would like to find that
same distinction point to the south. While some wells on
River Road south of the site were relatively clean, others
were still highly polluted. While U.S. EPA believes
sufficient knowledge has been gained to undertake the action
discussed in the Proposed Plan, further refinement of the
southern limits of contamination may be needed. U.S. EPA
also is appreciative of this citizen's views on the need to
have better 'give and take*. U.S. EPA notes that earlier in
the day, we did conduct a less formal availability session
in an attempt to serve this purpose. If some people's
personal schedules prevented them from attending, please be
assured we are a phone call or a letter away. Also,
U.S. EPA doee maintain local information repositories, so
that information can be reviewed in more depth.
COMMENT 15i
Mr. Vogel, area resident, notes that more detailed
information would help citizens comment.
RESPONSE: U.S. EPA refers to the response given on the third part of
the previous comment.
COMMENT 16:
Mr. Gollach notes he believes the extraction wells will be
in the creek.
-------
RESPONSE:
COMMENT 17:
This is not correct. U.S. EPA envisions extraction wells
set back somewhat from the creeks.
Mr. Velsner suggests the possibility of 'well mobility* in
going from one pocket of highly contaminated groundwater to
another.
RESPONSE: Regrettably, U.S. EPA is not aware of how we may make the
wells mobile. However. U.S. EPA believes this comment hits
upon an important point. While U.S. EPA sees a clear role
to be served by extraction wells in the vicinity of the
creek acting to intercept contamination before it enters the
creek system, U.S. EPA sees value in other wells located
near areas of high contamination, and will explore this
concept in the Feasibility Study (PS) for the site.
COMMENT 18>
Mi. Hamil, area resident, notes that she finds it
implausible for all of the contaminated groundwater to run
into the Little Bear Creek system, and is concerned about
possible movement to the west.
RESPONSE: U.S. EPA notes that upon review of site information, we too
express doubt in the view, expressed by certain PRP
representatives, that Little Bear Creek is the ultimate
receptor of groundwater flow from the site. It appears to
U.S. EPA that Little Bear Creek's influence on the
groundwater regime in the area must be finite. While Little
Bear Creek does appear to receive a considerable loading of
pollutants from shallower aquifer portions, there must be a
subsurface depth below which Little Bear Creek cannot
influence flow. U.S. EPA is evaluating ground water
remediation for the entire site in the PS currently in
preparation. This PS will deal with groundwater flow
besides that in the Little Bear Creek area.
-------
COMMENT 19: Ms. Ames, area resident, regrets the lack of a question and
answer session during the comment session.
RESPONSE:
COMMENT 20:
RESPONSE:
U.S. EPA notes that many citizens took advantage of a
question and answer session held immediately afterwards.
Ms. Harrison expressed concern over the fate of the water
table, and whether well users should be concerned.
Please refer to the response below to Mr. Gollach's written
comments (see Written Comment No. 2), which touched on a
similar point.
COMMENT 21:
Mr. Gollach observed that he hopes the drinking water
available to the panelists was not from the site, because
we'll never get the place cleaned-up if it is.
RESPONSE: U.S. EPA notes that we are still here. Evidently, the
water's source was elsewhere.
WRITTEN COMMENTARY RECEIVED DURING PUBLIC COMMENT PERIOD
COMMENT 1: August 18, 1989 — Mr. Veisner recommends the dredging out
of sand/sediments in the vicinity of the Bowmen's Club.
RESPONSE: We believe that the act of Intercepting contaminated
groundwater and providing adequate treatment will allow
opportunity for stream recovery. We do not believe removal
of sediments is necessary initially. However, U.S. EPA does
not rule out the possibility of future sediment removed to
enhance stream recovery. Any such action though must be
carefully considered so as not to cause undue siltation
problems. The effectiveness of the groundwater
interception and impact upon stream recovery will be
10
-------
carefully monitored, and, if deemed necessary in the future,
sediment removal will be considered.
COMMENT 2: Mr. Gollach delivered written material to U.S. EPA at the '
August 16, 1989 public meeting. Mr. Gollach urged that a
health study be done, and expressed concern over the zone of
influence of extraction wells.
RESPONSES U.S. EPA shares Mr. Gollach's concerns about human health.
The Agency for Toxic Substances and Disease Registry (ATSDR)
is aware of the circumstances surrounding this site and is
evaluating the need for this study. The U.S. EPA has
modelled the influence of the extraction wells on the water
table of the upper aquifer. Based upon the modelling
results, the cone of influence created by the pumping wells
along the unnamed tributary and Little Bear Creek is
approximately 3,000 feet at its maximum radial distance.
The upper aquifer in the vicinity of the 0/S/C site has a
relatively high transmissivity (40.000-60.000 gpd/ft).
Wells pumping at the Nor-Am Chemical site, 5,000 feet south
of the 0/S/C facility, pump approximately 200-500 gpm
without causing a significant (less than 1 foot) decrease in
the groundwater table. The proposed extraction wells will
have no significant influence on the water table in the one
to three mile radius.
COMMENT 3: August 21, 1989 from U.S. Dept. of the Interior (DOI)--Pish
and Wildlife -- Letter urges U.S. EPA to consider placement
of the extraction wells on higher ground away from the
creeks such that construction in the floodplain/wetlands
area is minimized and that seeps within the floodplain can
also be intercepted. It is also recommended that the level
of treatment specified in the NPDES permit be consistent
with the recipient water body's designation as a trout
stream. U.S. DOI also urges discharge to Little Bear Creek
11
-------
of treated water at a relatively upgradient position in
order to supply water to preserve wetlands and help •flush"
the creek.
RESPONSE: U.S. EPA appreciates the comments from the Fish and Wildlife
Service. As the extraction system is envisioned, the impact
and zone of influence of the pumping wells will indeed
provide protection to the flooded wetlands, as well as the
impacted areas of the two creeks. Extraction wells will
definitely be placed upgradient out of the
floodplain/wetlands. Only minor construction is envisioned
for the surface water discharge location. We intend to
supply such information to the selected contracting firm
that develops the Remedial Design Plans for this action.
U.S. EPA will also note these concerns in the Statement of
Work it will supply to such design contractor.
COMMENT 4< August 24, 1989 from counsel for CPC, International. Letter
notes that U.S. EPA is creating two groundwater treatment
plans, that this first plan only has an envisioned life of
five years, that there can be no conclusion of imminent and
substantial endangerment with regard to this action, that
air quality data is unusable and conclusions made from its
usage not appropriate, and that the only toxicity problems
in Little Bear Creek are related to certain metals not
associated with the site.
RESPONSEi U.S. EPA is not creating two groundwater remedial actions.
This action is to alleviate a surface water contamination
problem while other evaluation proceeds. U.S. EPA perceives
that a portion of the overall contaminated groundwater
system, namely that portion in the vicinity of Little Bear
Creek, is the source of the surface water problem. Hence,
this is a limited action to control that source. The goal
at this time is not one of groundwater remediation, but of
12
-------
stream recovery and the protection of human health. The
assertion that there is no imminent and substantial
endangerment is incorrect. The results p'f the endangerment
assessment show that contaminants entering .the ambient air
from the groundwater discharges pose excess lifetime cancer
risk to human populations. Clearly the organic pollutants
found in the Little Bear Creek system match the pollutants
in the monitoring wells at 0/S/C. As shown in the following
table, the levels of certain hazardous substances found in
Little Bear Creek and derived from the entry of contaminated
groundwater, exceed drinking water criteria (benzene, vinyl
*
chloride, 1,2-dichloroethane), Michigan ambient water
quality criteria (chloroform and vinyl chloride), and
U.S. EPA criteria for water-organism ingestion (benzene).
Further, all these organic compounds noted above are known
or probable human carcinogens.
Benzene
Chloroform
1,2-dichloroethane
Vinyl chloride
DSEPA
MCL
(ug/1)
S
.
S
2
Michigan
Rule 57
Water Quality
Guidelines
(ug/1)
51
43
560
3.1
Ambient
Water
Quality
Criteria
Ingast-
ion of
Water
& Pish
(ug/1)
0.66
0.19
0.9A
2
Observed Stream
Concentration
(ug/1)
26
85
140
52
U.S. EPA clearly identified within the RI that copper and
mercury levels were high throughout the stream valley and
not lite related. The assertion that these metals are the
only substances of a toxic nature is incorrect, given the
carcinogenic behavior of the organics discussed. U.S. EPA
believes these findings of surface water quality in itself
justifies a conclusion that there is an imminent and
13
-------
substantial endangerment. Given the volatile nature of
many of these compounds, U.S. EPA also perceives that their
entry into the air from the stream creates an exposure
pathway for persons nearby. U.S. EPA believes that the
11/13/86 MDNR memorandum from R. Teoh—placed in the
Administrative Record--justifies usage of certain MDNR air
data.
The consultant for CPC, Mr. Lodge, notes that "it is clear
that these compounds are leaving the water and entering the
atmosphere*.
The validity of the methods used in the RSI report in its
air model is in question, as noted in Mr. Teoh's review, the
results and conclusions, however, are interesting. The RSI
report concludes that the result, generated by using
•actual* field data, show the air concentrations are below
MDNR air standards and there is 'no risk*. The following is
a table showing RSI calculated air concentrations!
AMBIENT AIR CONCENTRATION (ug/m3)
Setting/Standard Bentene Vinyl Chloride 1.2-dichloroethane
3 m mix height , 0.00725 O.OS59 0.231
Michigan AAC (1x10 ) 0.14 0.4 0.09
U.S. EPA notes that the RSI figures related above shows the
predicted concentration for 1,2-dichloroethane is 2.6 times
the Michigan AAC, not below, as stated. Interestingly, the
modelled data concurs with the conclusions generated in the
RI's Endangerment Assessment. Risks calculated by U.S. EPA
using the EA's exposure assumption are shown below:
14
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Compound
Benzene
1,2-dichloroethane
Vinyl chloride
Modelled
RSI Air Concentrations
0.00725
0.231
0.0559
Excess Lifetime
Cancer Risk
Due to Inhalation
5.5 z
5.5 x
10
10
4.3 x 10
-8
-6
-6
AGGREGATE RISK:
9.8 x 10
-6
U.S. EPA often considers an excess cancer risk of 1 x 10"6
as a 'benchmark* of protection. U.S. EPA is concerned when
a risk is found to be greater than this level. Hence, your
figures clearly demonstrate an excess cancer risk factor
greater than 1 x 10~ for the current use air inhalation
pathway. Hence, U.S. EPA believes that taking any action to
help eliminate such a pathway is fully justified.
COMMENTS 51
August 25, 1989 from counsel for CPC, Int'l. This letter
resubmits ten previous letters to U.S. EPA from CPC, Int'l.
counsel and indicates they be given consideration in U.S.
EPA's responsiveness summary. While the primary purpose of
the public comment period is to receive comment on the
Proposed Plan, however items written prior to the public
comment period cannot be written with that purpose in mind,
therefore, U.S. EPA will respond as follows»
(1) February 10, 1989 -- CPC, Int'l. counsel protests U.S.
EPA not providing via POIA request a certain draft
statement of work and certain residential air sampling
data.
RESPONSEi U.S. EPA does not release draft work products. U.S. EPA was
requested by ATSDR to gather certain air data in the
vicinity of the 0/S/C site. In this matter, U.S. EPA feels
it is inappropriate to release such data prior to ATSDR's
having had an opportunity to review and comment upon data it
requested. ATSDR often views data it requests as medically
related and upon consultation with ATSDR, U.S. EPA believes
it acted properly in this matter.
15
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RESPONSE:
(2) February 13, 1989 — CPC, Inf1. counsel notes certain
items as to sale and transfer of Story Chemical to
Cordova Chemical, and notes certain instances of
incinerator explosion at the site.
For the purpose of considering relevant comment on the
Proposed Plan, no response is required.
(3) February 14, 1989 — CPC, Infl. counsel writes to U.S.
EPA stating that the creek interceptor has merit if it
stands alone, but if further aquifer remediation is
considered then the interceptor is inappropriate
because it is "inconsistent* with the final remedy.
RESPONSE: CPC's contention that the interceptor system is a viable
option for the full site remediation is unfounded. The
objective of the PFS is not restoration of the aquifer, as a
whole, put prevention of groundwater discharges into the
creek system. The creek interceptor does not address the
highly polluted groundwater at the site as evidenced by Well
W101D, nor does it address the southerly component of the
groundwater contaminant plum*. To state that the proposal
action is inconsistent is to ignore the overall scope of
actions required for the full site. The creek interceptor
is but one component of the overall remedial action.
(4) February IS, 1989 — CPC, Inf1. counsel write to U.S.
EPA objecting to U.S. EPA referring to Little Bear
Creek as a fishery resource.
RESPONSE: Please refer to the 07/28/89 memorandum prepared by V. Davis
of U.S. EPA and the 12/11/87 letter from the Department of
Interior placed in the Administrative Record for a more
detailed response. For the purposes of this Responsiveness
Summary, U.S. EPA believes the State of Michigan is correct
16
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in classifying a stream baaed on its potential for usage and
not ita current degraded state. U.S. EPA further notes that
it does not feel bound to concur with the methodology and/or
conclusions of any study in which it did not have an
opportunity to have meaningful input as to scope or
objective.
(5) March 1, 1989 — CPC, Int'l. counsel demand $3,022,105
for CPC incurred response costs at the 0/S/C site.
RESPONSE: Please refer to U.S. EPA'a demand letter of March 3, 1989
placed in the Administrative Record for this site as being
indicative of U.S. EPA response. Please note that the U.S.
EPA demand for approximately $1,300,000 la substantially
leas than CPC'a alleged expenditure through December 1988 of
approximately $1,673,830 for *recoverable' attorney's fees.
(6) March 14, 1989 — CPC Int'l counsel takes exception to
the uae of MDNR air data and diaagreea with the
comparison of the ATSDR air data with MDNR air data.
RESPONSE! U.S. EPA addresses the iaaue of MDNR air data in the
responae to Written Comment 4. CPC misconstrues our
inclusion of the ATSDR reference. U.S. EPA included the
reference In the RI to ATSDR samples aa a point of
completeness. Sample holding time excedencea prevented
inclusion of the data in the report. U.S. EPA has never
attempted to compare ATSDR data to MDNR air data aa stated
by CPC.
It la important to consider the reason, however, why ATSDR
decided to request reaidential sampling. ATSDR became
concerned over the preaence of certain organic compounds in
the sump water of a reaidence along Central Road. The
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sample collection and analysis was performed by CPC
consultants and the results of the 2/16/88 sampling have
been placed in the Administrative Record. In particular,
ATSOR was concerned over the presence of vinyl chloride,.
because it is a known human carcinogen capable of posing a
threat via the air inhalation pathway. Further, to the best
of U.S. EPA's knowledge and belief, these analytical results
were not forwarded to state or federal authorities by your
representatives, but rather by a concerned citizen.
(7) March 14, 1989 -- CPC, Int'l. counsel notes a series of
studies they have performed, instances where they
allege U.S. EPA is making use of such studies, and
conclude by asking if CPC shall continue this oversight
activity and to confirm authorization to incur costs.
RESPONSE: As noted above, U.S. EPA does not feel bound to concur with
methodology and/or conclusions of any study in which it did
not have opportunity to have meaningful input as to scope or
objective. U.S. EPA notes that your usage of the term
•oversight* is highly inventive.
(8) March 14, 1989 — CPC, Int'l. counsel states to U.S.
EPA that a Michigan DNR letter to U.S. EPA misstates
facts as to when off-site migration of a plume of
contaminated groundwater occurred.
RESPONSE! U.S. EPA notes that establishing when such event occurred is
not germane to the task of selecting a remedy which will
protect human health and the environment as a result of such
groundwater plume movement and subsequent entry into surface
waters of a portion of such plume.
(9) July 11, 1989 — CPC, Int'l. counsel provides certain
information concerning off-site dumping related to the
0/S/C site.
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RESPONSE: Other than to place this document in the Administrative
Record, no further response is required of U.S. EPA.
(10) July 26, 1989 letter from CPC, Int'l. counsel
criticizing numerous elements within the RI.
(a) Counsel states that there is a limited analysis of
existing data and information on the site in the RZ and
precludes an interim remedy.
RESPONSE! U.S. EPA disagrees with CPC's contention that an interim
remedy is precluded at this stage because of a lack of
information, such as groundwater quality. Indeed, given
CPC's past stance on the matter - that all substantive
matters are known on the site, that the data point to no
action or an alternative limited to occasional monitoring,
and that past U.S. EPA suggestions that there may be data
gaps are merely a 'schizophrenic attempt* to avoid the
obvious conclusion of no action - it is interesting that CPC
would now tell us that a lack of information should preclude
U.S. EPA from recommending a prudent first course action.
(b) CPC states that the issue of deep aquifer flow and
extent of contamination remain unresolved and that to
continue with the actions at Little Bear Creek will
•contradict, overlap, or duplicate* the interim action.
RESPONSE: U.S. EPA will address the issue of contamination of deeper
portions of the aquifer in the overall site feasibility
study, now undergoing preparation. U.S. EPA perceives that
the majority of pollutants in groundwater near the Little
Bear Creek system are in hydrogeologic zones 'A* and *B',
as noted within the Remedial Investigation. Deep wells
towards old production areas do appear contaminated.
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U.S. EPA will consider how to deal with such deeper lying
contaminants; care must be given to avoid drawdown of more
grossly polluted shallow aquifer groundwater into deeper
zones.
(c) CPC states that it will be impossible to select a
treatment system without further identification (of
unknown contaminants) or a treatability study.
RESPONSEi U.S. EPA recognizes the complex nature of the groundwater
contamination problem. As you well know, the list of raw
materials and products made at this site read like an
organic chemistry textbook. As you further know, the
analytical procedures employed by U.S. EPA laboratories and
its contract laboratories are geared toward the more
commonly used chemicals in commerce, out of a universe of
literally hundreds of thousands of such compounds. We then
arrive at a complex question: Do we postpone a decision at
a site, ignoring the clear risks posed by the positively
identified hazardous substances, and wait until all
compounds are known, or do we declare that a sufficient body
of information is known and that our duty is to act to
protect public health and the environment?
U.S. EPA believes that the risks posed by compounds
positively identified are serious enough to warrant
recommendation of a course of action as is developed in the
Focused Feasibility Study. This is not to say that U.S. EPA
dismisses the question of compounds only tentatively
identified. Indeed, your assumption is correct. U.S. EPA
will develop a treatability study to deal with the issue of
how best to treat the complex mixture of groundwater
contaminants at Ott/Story/Cordova. U.S. EPA also believes
that reliance only on standard physical-chemical criteria
may not be sufficient to adequately judge treatment of so
complex a mixture.
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(d) CPC strongly takes issue with the characterization of
the risks presented by air emissions at the site.
RESPONSE! The 1986 MDNR air data was discredited, as you term it, by
you and your consultant. We also note that MDNR reviewed
the 'RSI* study you point to, and found considerable fault
with it. It seems prudent to U.S. EPA to note the cdncerns
of state agencies charged with protecting the well being of
their citizens.
Please also refer to the response to Written Comment 4 which
address this issue.
(e) CPC contests the concept of "buried drums or waste" at
the site, stating that plant records do not support
this scenario.
RESPONSEt U.S. EPA, in reviewing data gathered in the RI's, saddened
and dismayed to note the astonishingly high levels of
contaminants in soils and groundwater near central portions
of the old production areas. Contentions raised by some,
that all of the material that could have entered the
groundwater has long since done so and that there is nothing
new to find out about the site because the last remnants of
this contamination are now bleeding off into Little Bear
Creek, appear to be in serious doubt. If all materials have
long since entered the groundwater and moved downgradient,
why then did U.S. EPA's well cluster W101, installed north
of Agard Road turn up such a large variety of contaminants
at such high levels? What can account for their presence?
U.S. EPA has received accounts from citizens of supposed
waste disposed at various points around the plant. In an
effort to investigate such reports in a cost-effective
manner. U.S. EPA has performed geophysical investigations at
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the site. We have found two areas yielding unusual
anomalies just south of Agard Road and south of the
equalization basin. These areas are in no way related to
utility lines, and U.S. EPA reserves the right to perform
exploratory borings as a part of feasibility study
development. Further, the concept of * source" of additional
groundwater pollutants is not limited to buried drums. We
perceive that the soils themselves in central areas of the
site pose a threat of further release of contamination.
(f) CPC has been given no opportunity to comment on a draft
RI before Region V announced it was final.
RESPONSE:
The U.S. EPA does not release draft documents to the public.
(g) CPC states that the only risks presented in the RI's
Endangerment Assessment arc premised on unrealistic
future use scenarios with flawed baseline data. CPC
argues that the contaminated groundwater plume has been
moving southeast from the site and discharging to the
unnamed tributary and Little Bear Creek since mid-1975,
and that some degree of natural recovery is occurring
in Little Bear Creek.
RESPONSE! 'Unrealistic future use scenarios'? We remind you that
once, before it was so hideously defiled, this aquifer
served as a potable drinking water supply, and as such
deserves protection as a Class II aquifer. Perhaps it
disturbs you that we bothered to calculate the degree of
risk that may be posed if on* happened to use groundwater
from the Ott/Story/Cordova site for a water supply. As you
know, as an Agency, we become concerned if a certain
incremental health risk to the public exceeds one in a
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million. But as the RI now points out, if a person used the
aquifer at well points OV9 or OV12 as a water supply, he
does not face a 1 in 1,000,000 or a 1 in 100,000 chance of
developing disease; no - he faces a risk of 99 out of 100
that he will develop cancer if he used such water to drink
over the course of a lifetime.
Further, we express doubt over your contention that it was
only since mid-1975 that the plume was moving southeast from
the site.
(h) CPC states that it is worth noting that, as indicated
in the attached (York Services, July 1989), the RI has
so far confirmed that the plume is purging itself over
a period of years (estimated to end between 1990 and
2019) and that 'simply put. Little Bear Creek appears
to be effectively volatilizing/assimulating the
contaminants of concern*.
RESPONSEt U.S. EPA notes that CPC's consultant refers to his
calculations yielding the years cited as 'speculative*.
U.S. EPA is surprised your letter of 7/26/89 did not also
advise of the speculative nature of the calculations.
U.S. EPA also takes note that your own consultant, again in
Exhibit 3, was not able to conclude that Little Bear Creek
is the ultimate barrier/receptor to all groundwater flow
from the Ott/Story/Cordova titt. This appears to bear out
similar concerns raised by U.S. EPA.
COMMENT 61 August 28, 1989 from counsel for CPC, Int'l. Counsel
alleges that the Administrative Record is seriously
deficient and notes that Section 117 of SARA calls for
reasonable opportunity for written and oral comment upon the
proposed remedy. Counsel further notes that U.S. EPA should
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extend the public comment period. Counsel further notes
that a public meeting must be held and the transcript made
available. Counsel further notes that the Administrative
Record be made available at or near the specific site.
Counsel alleges U.S. EPA has not prepared an index for
materials in the Record. Counsel reminds U.S. EPA of the
need to provide for participation of interested persons in
development of the Administrative Record. Counsel again, as
per earlier comment, objects to U.S. EPA withholding certain
residential indoor air sampling results despite FOIA
requests for all records. In a similar manner. Counsel
alleges the absence of information about the ultraviolet
oxidation process.
RESPONSE: U.S. EPA notes again the obvious: That a public meeting was
held August 16. 1989 in the Dalton Township Hall to consider
comment upon the Proposed Plan. As noted earlier despite
the fact that U.S. EPA hat received only one request to
extend the public comment period (from counsel for
CPC, Int'l), U.S. EPA extends the time for receipt of
written commentary. U.S. EPA sent on August 31 to
CPC, Int'l. counsel a copy of the Administrative Record
Index at it existed through Augutt 10, 1989. Obviously,
U.S. EPA will adjust this Index to reflect receipt of
comment. U.S. EPA notes that the entire Record is indeed
available at or near the site, namely at the Walker Memorial
Library in North Muskegon. U.S. EPA emphatically denies
that the Record it seriously deficient, or that U.S. EPA has
precluded participation of interested persons in Record
development. U.S. EPA cites the voluminous inclusion of
materials tent to U.S. EPA by CPC, Int'l. counsel in the
Administrative Record.
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U.S. EPA again states that it does not feel bound to accept
the conclusions of reports or studies in which it had no
opportunity for meaningful participation. Finally, U.S. EPA
again denies that it wrongfully withheld data, and cites its
response to the August 25 comment noted above.
COMMENT 7: August 28, 1989 letter from CPC, Int'l. counsel listing
various questions concerning the RI/FFS.
(1) Are any of the wetlands characterized or otherwise
identified?
RESPONSEt The RI report extensively discusses and characterizes the
Little Bear Creek and the unnamed tributary. The concept of
floodplains and wetlands are basic to any impact or remedial
action discussion. Items supplied in the administrative
record reflect the impacted areas classification as flooded
wetlands and protected ecosystems (Memot 12/11/87, U.S.
Dept. of Interior - Fish & Wildlife Service)
(2) Are performance standard protocols available for
physical, chemical, and biological indicators?
RESPONSES The performance standard protocol to be used to verify the
effectiveness of the remedial actions are to be based upon
the stated goals and objectives of the FFS. Detailed
monitoring protocol are dtvtloptd in tht Work Plan for the
Remedial Design. It is inappropriate in the FFS or Proposed
Plan to develop this detail.
(3) Have the water quality and quantity and flow dynamics
of the surface waters been characterized sufficiently
to determine the impacts from the proposed stream
discharge?
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RESPONSE: The U.S. EPA has provided details of the proposed stream
discharge to MDKR for consideration in the development of
the NPDES limits. Included in this information are proposed
discharge rates and locations as noted in the appendices.
Sufficient information is available to proceed with the
discharge limit development.
RESPONSE]
The FPS continues to suggest the presence of buried
wastes as contaminant sources. Is there any date to
support this continuing assertion?
Please refer to Written Comment 5.10.e.
(5) The groundwater modelling does not allow for adsorption
or retention in the soil/groundwater matrices. How
does this fact affect the suggested size, shape and
concentration profile of the plume?
RESPONSE: The modelled size of the groundwater contaminant plume was
approximately 15 percent greater than suggested in the RI.
However, the concentration of contaminants and the general
shape of the plume are the same as discussed in the-.RI.
(6) Why is the 'shorthand* sum of organic constituents used
to express plume definition rather than the analytic-
ally measured (TOO) parameter?
RESPONSE: The use of the 'total organic contaminant* is the summation
of actual analytically measured individual groundwater
contaminants. The parameter, the commentor suggests be
used, TOG (Total Organic Carbon), although an analytical
measure, ie a gross indicator parameter of general
contamination, and is not as meaningful as the actual
contaminant totals in defining the level of pollution found.
26
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(7) Has any theory or explanation been forwarded to explain
why OW-12 contamination is orders of magnitude greater
than similarly situated wells?
RESPONSE: A comparison of monitoring well screened at 'similarly
situated* geologic intervals and depths as OW-12 in the
contaminant plume did indeed have similar magnitudes of
contamination. These wells include OV23, OW9D, W24, W25,
and K280. It is interesting to note that OW-12 is locally
known as the "root beer* well because the dark amber color
of the groundwater and of its foaming action when sampled.
(8) Can Little Bear Creek accept a 400 gpm discharge
without erosion or other negative in-stream impacts?
RESPONSE! The impact of erosion on the stream due to discharge at
Little Bear Creek will be minimal. As cited in your
•Exhibit 3* of your July 26 RI review, Little Bear Creek has
an approximate flow of 9.2 ft /second and an 'average plume
discharge* of 0.31 to 0.97 ft /sec. The proposed discharge
of 400 gpm (0.99 ft /sec) would have minimal impact on the
receiving stream. The engineered discharge structure would
prevent erosion by minimizing the discharge velocity.
(9) How are meaningful evaluations of treatment options
being considered when 85Z of the TOC contamination is
undefined? Are the result! of bench and/or pilot scale
testing available for various treatment train components?
RESPONSE! The U.S. EPA believes that given the high BOD level found in
several wells, conventional biological treatment has a role
to play, provided initial treatment steps help eliminate the
toxicity problems associated with the pollutants. Various
bench-scale studies have been performed on 0/S/C groundwater
previously (Shuckrow, Pajak, Oseka, and James, 1980;
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Touhill, Shuckrow and Associates, Inc., 1979; James,
Shuckrow and Pajak, 1981). The U.S. EPA has also initiated
preliminary bench-scale testing of the UV enhanced oxidation
process using groundwater from the site. The results of the
bench-scale testing are currently being evaluated.
(10) How were treatment modules paired with extraction/
collection modules?
RESPONSE: The methodology we used to- combine treatment technologies
with extraction/collections modules were defined in the FFS.
We refer the commentors to this document.
(11) What is the status of the UV pilot/bench scale testing
in? Are the results available?
RESPONSE: Please refer to comments supplied above in Written
Comment 7.9.
(12) What are the current FS plans for POTW use?
RESPONSE: U.S. EPA, as noted in the FFS, is considering the impacts of
discharge upon the POTW, potential capital improvements
required for the additional flows and indications from POTW
officials that the discharge may not be accepted. In light
of these issues, the POTW use for the FS is not being
considered.
(13) What are the expected effects of FFS remedial plan on
stream flow regimes? How do they effect stream biota?
Is the drying-up of the streams detrimental to natural
systems including wetlands?
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RESPONSE: Elimination of the groundwater discharge to Little Bear
Creek and the unnamed tributary will reduce stream flow.
Surface water flow to the tributary would be reduced to
runoff due to precipitation. The effect may be detrimental.
to the wetlands. For this reason, U.S. EPA is carefully
considering the commentary provided by U.S. 001 - Fish and
Wildlife Service on stream locations in an effort to
preserve the wetlands.
(14) What are the NPDES discharge objectives under consider-
ation by MDNR? How do they compare to the POTW require-
ments?
RESPONSE! The U.S. EPA has received from MDNR the requirements for the
NPDES discharge. They are available in the Administrative
Record for your review and comparison.
(15) If MCL standards do not apply to the surface water
discharge, and NPDES standards will be developed at a
later date, and current levels are below USEPA WQC,
what effluent levels were used for treatability
technology screening analysis in the FFS?
RESPONSE: The commentor incorrectly uses the current surface water
analytical results to compare to limitations placed upon a
treatment technologies discharge. As can be seen in
Appendix B of the FFS, the U.S. EPA Water Quality Criteria
and the Michigan Surface Water Quality Guidelines were used
in considering these technologies.
(16) Has a complete inventory of all existing monitoring
well data been completed?
RESPONSE: An inventory of known monitoring well data is supplied in
the RI/FS Work Plan.
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(17) Why hasn't the creek underflow issue been resolved?
RESPONSE! The U.S. EPA firmly believes that Little Bear Creek has
only a limited ability to influence groundwater movement •
particularly in Zone C. Groundwater in the semi-confined
system, Zone C, is not expected to be significantly
influenced by the creeks and therefore continues to flow
east/southeast below the creek.
(18) Are seep sources located and quantified?
RESPONSE: Ground water seeps to Little Bear Creek are evident from the
confluence of the unnamed tributary and Little Bear Creek to
south of River Road. Seeps to the unnamed tributary are
evident from the dam of the pond behind Bowman's Club to the
confluence of the unnamed tributary and Little Bear Creek.
It it alto probable that seeps occur beneath the surface
waters of the tributary, and Little Bear Creek. While
quantification of the number of seeps has not been made, it
is not necessary to know the number to proceed with the
remedial action.
(19) Is permanent stream flow instrumentation planned?
RESPONSE: The U.S. EPA is not currently contemplating installation of
permanent stream flow instrumentation. MDNR currently
maintain ttaff guages in the creek. We do reserve the right
to implement such instrumentation in the future.
(20) It a 400 GPM purge rate necessary? Rather than dewater
the tributary would a reverse hydraulic gradient from
the tributary to pump-out wells be adequate?
RESPONSE: U.S. EPA believes, based upon our analysis of the ground-
water system, the 400 gpm it necettary and appropriate to
achieve the objectives of the Proposed Plan.
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(21) Could the treatment facilities be relocated from the
0/S/C Site closer toward the purge and discharge point
(i.e., near River Road) to reduce costs for piping and
pumping?
RESPONSE: U.S. EPA believes a treatment site nearer to the 0/S/C
facility may be more implementable because it imposes less a
burden on residentially held land near the streams.
(22) Explain the air sampling programs that provided data
for use in the RZ and endangerment assessments. Are
QA/QC available? Are the ATSDR results available for
the 1988 samples?
RESPONSE! The commentor is referred to response to Written Comment 4,
which addresses this issue.
(23) Why were institutional controls as an independent
interim measure not fully evaluated?
RESPONSEt U.S. EPA believes it is inappropriate to speak in terms of
•institutional controls' to address surface water
degradation problems in streams where, to the best of U.S.
EPA's knowledge and belief, the stream bank land is not
owned by potentially responsible parties connected with this
site. The citizens living in the vicinity of River,
Central, and Russell Roads near this site have been denied
for years full usage opportunity of a stream which is
rightfully theirs, due to a problem caused not by their own
doing, but by releases having their origin at the 0/S/C
site. The Muskegon County Health Department (MCHD), upon
the recommendation of the Michigan Center for Environmental
Health Study, placed warning signs in Little Bear Creek some
2-3 years ago, warning potential users of contaminated
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water. During the public availability session on August 16,
one MCHD representative was heard by U.S. EPA to remark that
it is time to order new warning signs, as the existing ones
are becoming too weathered. U.S. EPA sincerely hopes this
will be the last time such an order is necessary.
(24) Explain the 'data verification* program.
RESPONSE: The 'data verification* program used by U.S. EPA at 0/S/C is
described in the Quality Assurance Program Plan for the RI
Work Plan.
(25) How were Modflow and Hocflow models selected for use
for this site? The assumptions and calibration used
for site modeling art not presented. Are they
available?
RESPONSE: Both the Modflow and Hocflow models have been utilized and
documented extensively in the literature. The principal
components of the modelling process have been included in
the supporting documents which are voluminous.
(26) Has the groundwater modeling identified the hydraulic
relationship between the unconfined and semi-confined
aquifers near the stream? If so, what is the hydraulic
regime in this area?
RESPONSE: In the vicinity of the streams little or no hydraulic
connection between the layers was possible as evidenced by
the large difference in hydraulic head between the layers.
Based on both existing groundwater data and the results of
the modeling effort, the groundwater flow system and the
fate and transport of contaminants can be characterized as
follows:
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Groundwaters in the unconfined zone approach the
streams to the east driven by a steep hydraulic
gradient. This hydraulic gradient is created by a
40 foot drop in topography from the 0/S/C site to .
the bottom of the unnamed tributary and Little
Bear Creek. Most of the groundwater in the
unconfined aquifer from the 0/S/C site flows south
below the existing stream channel following the
groundwater flow created by the unnamed tributary
and Little Bear Creek.
Groundwaters in the semi-confined zone approach
the streams to the east/southeast, but are driven
by a much smaller hydraulic gradient. Confining
layers between the two aquifers limits leakage
between the aquifers, thus as groundwaters in the
semi-confined aquifer approach the streams to the
east/southeast the hydraulic heads decrease at a
much slower rate than the hydraulic heads in the
unconfined zone. This creates a steep upward
hydraulic gradient between the two zones in the
vicinity of the streams.
Groundwater contaminants (dissolved) in the
unconfined aquifer will flow east/southeast until
they reach the stream channel. At the stream
channel the contaminants will either enter the
streams as groundwater seepage or flow south below
the stream channel. The limited number ground-
water contaminants detected in wells screened in
the unconfined aquifer east of the unnamed
tributary and the presence of fairly high levels
of groundwater contaminants in wells OW-12, and
OV-23 supports this conclusion.
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o Groundwater contaminants in the semi-confined zone
will continue to flow east/southeast remaining
relatively unaffected by topographic features.
This conclusion is supported by the presence of
semi-volatile groundwater contaminants in wells
east of the unnamed tributary.
(27) Have the groundwater models suggested fate and
transport regimes for various plume contaminants?
RESPONSES
Please refer to the above written comment.
(28) Was constructing the purge wells along the axis of the
plume considered?
RESPONSE! Capture the plume beyond eliminating seepage of contaminated
groundwater was not the objective of the FFS pumping wells.
Placement of the extraction wells perpendicular to the axis
of the plume at the creek is the most effective method of
intercepting groundwater discharges.
(29) What is the sensitivity of treatment costs and
effectiveness based on influent groundwater contaminant
levels?
RESPONSEi Influent ground water contaminant levels have been predicted
based on ground water modeling of the flow regime at the
site coupled with current analytical results of samples
taken from onsite ground water monitoring wells. The
resulting influent concentrations that were predicted are
expected to compare closely with the actual influent
concentrations from the extraction options. The sensitivity
of treatment costs and effectiveness of treatment will
therefore be minimal. The recommended treatment process
train has been formulated to be able to handle not only
small fluctuations in concentration but also the larger
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RESPONSE:
changes in concentration that are expected to occur over
time. The effects are most noticeable in carbon adsorption
costs which are expected to decrease with time as dilution
effects are encountered. The carbon adsorption unit will
act as a buffer to the other treatment options. As
concentrations increase the carbon unit will remove more
contaminants and vise versa for a decrease in influent
concentration.
(30) Why does the interim remedy have a 5-year design life?
Cost evaluations for remedial alternatives in the
PPS were based upon a 'five year design life'. As stated in
the FFS, this is because future remedial actions at the
0/S/C site may have a major impact upon operational and
maintenance cost over the lifetime of the remedial action.
The cost consideration may require re-evaluation once the
full site remediation has begun. The actual 'working life*
of the proposed FFS action is far longer than 5 years.
(31) Will any of the proposed interim stream remediation
plans reduce surface H.O or sediment metal
concentrations?
RESPONSE! The U.S. EPA believes that concentrations of metals in the
surface water and sediments are related to background
concentration! and as such, require no remediation on this
basis.
(32) How are the preferred FFS alternatives considered
•fundamentally compatible* with the probable FS
remedies?
RESPONSE: U.S. EPA perceives three problems at 0/S/C — Contaminated
soils, contaminated groundwater, and contaminated surface
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water caused by a portion of the contaminated groundwater.
Thii action will address the latter instance of contamina-
tion.
COMMENT 8: August 30, 1989 letter from CPC, Int'l. counsel to U.S. EPA
noting that "as you know* CPC initiated the concept of a
Little Bear Creek interceptor remedy in 1987, U.S. EPA'a
groundwater pump and treat scheme is wholly unjustified,
that U.S. EPA violates its own guidance, and that no
imminent hazard exists at the 0/S/C site.
RESPONSES U.S. EPA, for reasons stated above in the response to CPC's
letter of August 24. 1989, notes that an imminent and
substantial endangerment exists at the 0/S/C site; hence, a
plan to alleviate certain of those hazards associated with
contaminated surface water is justified. U.S. EPA notes
that the citation provided by CPC counsel, p. 3-8, is
incorrect. The quotation noted by CPC may be found on p.
3-4. U.S. EPA believes CPC assertion, that the zones of
contamination are closely interconnected and "defy
compartmentalization* is also incorrect.
U.S. EPA believes the geological zones cited in the RI are
sufficiently different, and that contamination in shallower
zones near the creeks may be addressed. U.S. EPA also notes
that p. 3-4 cites other factors that "... can help to
identify potential operable units...' One of these is
•Presence and location of hot spots — Can a remedial action
be implemented to reduce or eliminate hot spots without
adversely affecting the overall plume?...* In this case.
the answer ie Yes I U.S. EPA perceives the surface water
contamination caused by the influx of a portion of the plume
as such a *hot spot*I
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U.S. EPA is also eager to respond to the comment, "As you
know... in 1987*1 No, U.S. EPA did not know of this
proposal in 1987, although CPC was apparently negotiating
with the State of Michigan over implementing an underdrain
collection system with no provision for treatment of the
contaminated groundwater. Indeed, as the Administrative
Record shows, a February 17, 1988 letter from counsel for
Aerojet to counsel for CPC suggested that maybe it would be
a good idea to eventually let U.S. EPA know what it was that
CPC had been discussing with Michigan. U.S. EPA also have
come to understand that one condition of Michigan acceptance
of this proposal was to have forbade Michigan from ever
providing its 10 percent matching share for any remedy U.S.
EPA might at some later point in time think appropriate.
U.S. EPA believes Michigan acted wisely in rejecting such a
condition.
COMMENT 9: Document generated by Wenck Associates and York Corporation
for CPC titled 'Technical Review, Focused Feasibility Study
for Ott/Story/Cordova Site, Muskegon, Michigan* dated August
1989.
(1) Section II, Review of Objectives
(a) The reviewers state that there has been no definitive
evidence presented in the RI or FFS indicating a
significant threat to tht environment.
RESPONSEi The U.S. EPA has reviewed all documents pertaining to the
impact of contaminated groundwater discharges to the Little
Bear Creek. The RI report documents extensively the
degradation of environmental quality in the impacted area.
We seriously disagree with the assumption that there is not
a significant threat to the environment due to surface water
contamination.
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(b) The reviewer asserts that alternative options 'notably
the institutional controls option* have been neglected
in the FFS.
RESPONSE:
Please refer to the response to Written Comment 5.10.
(c) The reviewer states that the 'risks identified" do not
necessarily indicate the need that a PFS be performed
for the groundwater operable unit at Little Bear Creek
and its unnamed tributary.
RESPONSE: The U.S. EPA proceeded with the FPS at this location to
control the source of contaminant input to the creek, most
notably the contaminated groundwater. To state that the
risks do not indicate the need for the FFS is unjustified by
fact.
(d) The review takes exception to inclusion of the stream
underflow in the objects and notes that the issue of
creek underflow is related to the semi-confined
aquifer.
RESPONSES The U.S. EPA agrees that the issue of stream underflow is
related to the semi-confined zone. However, analytical
results during the RI do indicate that contamination has
traveled east of Little Bear Creek in the unconfined system.
RESPONSE:
(f) The reviewer questions the •integrity and
applicability* of the air data used to generate the
endangerment assessment.
Please refer to the response to Written Comment 4 which
addresses this issue.
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(g) The reviewer comments that the risk assessment used
•qualitative terms* when discussing the calculated risk
at Little Bear Creek.
RESPONSE: The U.S. EPA, in describing the health risks at Little Bear
Creek, did indeed use qualitative descriptions of the
serious risk incurred by volatile emissions at the Creek.
We also backed up these qualitative description with actual
quantitative results which the review has overlooked.
(h) The review asserts that the risks identified in the FFS
associated with the use of groundwater as a potable
source are not justifications that a *PFS be
performed*.
RESPONSE:
Please refer to the response to Written Comment S.lO.g.
(1) The reviewer questions why the institutional controls
option, while returned for inclusion of each response
action, is not and of itself referred to as an interim
option.
RESPONSEt
Please refer to the response to Written Comment 5.10.
(2) Section III - Compatibility with Long-term Remedies
(a) Tht reviewer questions the compatability of the
pump-out system with any long-term solution at the site
and states the system may actually make the situation
worse.
RESPONSE: The U.S. EPA questions how this situation could actually
become much worse than it is. The pump-out wells were
considered as an interim action which would be compatible
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with any remedial action that will be implemented at the
site.
(b) The reviewer contends that the RI did not contain ample'
hydrological data to analyze the complex hydrogeology
of the site.
RESPONSEt The volume of hydrogeological data available in the RI was
more than sufficient to calibrate both groundwater flow
models to existing site conditions.
(c) The reviews state that the presentation of four
stratigraphic zones (A through D) as presented in the
RI is an oversimplification and obscures the complexity
and variability of the underlying lithology at the
0/S/C site.
RESPONSE: The simplification of complex settings is practiced in
virtually every branch of science and engineering in order
to allow the development of solutions to problems.
Hydrogeologic data collected at the 0/S/C site to date
indicates that the four units outlined in the RI report do
have local variability, but they can be correlated across
the site. In addition, it is common practice in complex
hydrogeologic environments to group similar geologic units
together and derive equivalent vertical and horizontal
conductivities bated on derivations of Darcy's law.
(d) The review questions how the groundwater models used
could provide a realistic representation of the site
during remediation and how applicable the models are to
the site.
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RESPONSE: Using the available hydrogeologic data it was possible to
calibrate both Modflow and Mocflow to existing site
conditions. Modflow and Mocflow are both United States
Geological Survey groundwater flow programs that have been
used extensively over the past decade to model a large
variety of hazardous and non-hazardous waste sites with
various degrees of complexity. Both models are marketed by
one of the largest groundwater modeling centers in the
nation, the International Groundwater Modeling Center in
Indianapolis, Indiana and extensive documentation, and
verification of both models is readily available.
(c) The reviewer questions the placement of the pumping
wells.
RESPONSE: The objective of the pumping well* proposed in the PPS was
not to remove contaminants from the most contaminated
portions of the plume at the facility, but to prevent
groundwater discharge into the creeks. Development of
optimal well configurations for the removal of contaminated
groundwater for the full site will be addressed in PS
report.
(f) Given the proposed configuration of the extraction well
locations, it is unclear if the extraction wells will
truly keep groundwater contaminants out of the stream
and meet the objectives of the PPS.
RESPONSE} The capture zone of the groundwater extraction system
outlined in the PPS extends north beyond OW-12. The plume
boundary outlined in the RI is an approximate boundary north
of OW-12. No groundwater seeps have been documented north
of OW-12. The groundwater flow direction (southeast) will
complement the well locations by enhancing groundwater
movement to the extraction well.
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(g) The review speculates that it may not be necessary to
extract groundwater at a rate of 400 gpm. It may be
only necessary to reverse the hydraulic gradient from
the tributary back to the extraction well. It may not-
be necessary to draw groundwater down below the
streambed.
RESPONSEt The U.S. EPA believes, based upon the modelling, that the
pumping rate of 400 gpm is necessary to prevent groundwater
seepage into Little Bear Creek and the unnamed tributary.
(h) The reviewer states that the construction of the slurry
wall may not be compatible with a long-term solution
because of the essential irreversibility of the action.
RESPONSEt The U.S. EPA agrees with the commentor about the potential
impacts of the slurry wall on the groundwater flow regime
and upon the remedies for the full site.
(i) The review questions by the configuration of the
extraction wells associated with the slurry wall and
whether it would be effective in capturing the
contaminated groundwater.
RESPONSE: The groundwater modelling of the slurry wall with two
extraction wells indicates that it would be effective in
meeting the objectives of the EPS.
(j) The reviewer notes that the clay zone that the slurry
wall is to be keyed into is not necessarily continuous
or well-defined across the area.
RESPONSE i The concerns of the reviewer are noted. The base of the
clay zone does vary across the site and there are some
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uncertainties associated with the construction of the slurry
wall. However, the slurry wall, to a depth of 90 feet, when
combined with extraction, was determined by modeling to be
effective in preventing migration of contaminants into the
creeks.
(k) The reviewer takes issue with the 'new* subject of
•wetlands* and the impacts of remedial actions.
RESPONSEi Discussions concerning the 'wetlands* associated with the
site are not new. Documents contained in the Administrative
Record (U.S. Department of Interior, 12/11/87) document the
Department of Interior-Fish & Wildlife Services concerns
about the impact of contaminated groundwater discharges on
the wetlands area.
(a) The reviewer believes the discussion of the negative
impacts on Little Bear Creek should have included other
studies.
RESPONSE:
Please refer to the response to Written Comment 9.1.a.
(3) Treatment/Disposal Technologies and Processes.
(a) The review questions why the rein jection/ infiltration
option was eliminated in the screening and wants to
know why it is 'not directly applicable to actions* at
Little Bear Creek.
RESPONSE! Th« U.S. EPA believes that the implementation of the
rein jection/ infiltration scheme to the remedial action at
Little Bear Creek is inappropriate because, at this time, it
is potentially incompatible with future actions at the 0/S/C
facility. The cost effectiveness of a limited reinjection/
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infiltration scheme is questionable. The review is correct
in noting that Figure 3-2 incorrectly retains the
reinjection/infiltration option.
(b) The review questions why the disposal option chosen in
the Proposed Plan is surface water discharge and not
the POTV. Further, an interim receipt of treated
groundwater may be allowed, according to an unnamed
official at the POTV.
RESPONSE! The U.S. EPA believes that the ultimate disposal of treated
groundwater should ultimately be surface water discharge
because it should not place the responsibility of final
treatment and ultimate disposal upon the Muskegon County
Waatewater Division (MCWD). Although the cost analysis and
comparison of alternatives in the FFS indicate that the POTW
is slightly leas costly, the choice of discharge location
considers not only costs but the interest of the community
and administrative feasibility. Concerns by MCWD about
their ability to handle the pretreated groundwater is
justified by previous bad experiences with 0/S/C discharges
to the POTV. The MCWD has stated that it would require a
substantial fee to help with the capital expansion to handle
the additional flow. This fee was not included with the
capital costs of the POTW analysis.
(c) The reviewer expresses concern over the 'inherent
uncertainties in implementation* of the UV-oxidation
process. The present worth costs for the UV-oxidation
option could be significantly greater than estimated.
The expected VOC removal efficiency are extremely
variable.
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RESPONSE: The UV-oxidation process is a relatively new and innovative
treatment process, as the review noted. The effectiveness
of the UV-process is dependent on the individual chemical
constituents molecular structure. As a pretreatment
process, the UV-process is very effective in eliminating
those volatile organics that are most toxic to biological
treatment systems. The commentor notes that present worth
cost for this process may vary significantly. This is also
true for other potential treatment processes as well.
(d) If the influent contaminant levels were significantly
different, will this impact the selection of available
treatment schemes?
RESPONSE: The U.S. EPA believes that the influent concentrations used
to develop the remedial technologies are very similar to
what will be encountered once the 'twitch is flipped* on the
extraction scheme. Any variety in influent concentration,
however, would have no impact upon the remedy selection.
(e) The commentor's notes on results of treatability
studies could have a major impact upon the treatment
processes that have been retained as viable
alternatives.
RESPONSE: As part of the screening process of treatment alternatives
for tht PPS, U.S. EPA reviewed a variety of published
treatability studies. including those performed on
contaminated groundwater from 0/S/C. This information was
used in eliminating those treatment processes that were
ineffective in dealing with contaminants similar to those
found at the site. U.S. EPA is currently conducting, a
bench-scale treatability study on 0/S/C groundwater using
the UV-enhanced oxidation process. Results of the tests are
currently being evaluated.
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(f) The reviewer states that not all groundwater treatment
options have been reviewed and screened by the FFS.
The review suggests three, including institutional
controls, one similar to Alternative 8 but with POTW.
discharge, and groundwater extraction followed by
wetlands treatment.
RESPONSE: The U.S. EPA feels that it has not been remiss in the
screening of treatment options. As previously stated in the
Responsiveness Summary, the concept of institutional
controls by itself is currently in use at the site and is
very ineffective in protecting the public or environment.
The second alternative, like Alternative 8, provides the
limitation inherent to the underdrain as discussed in the
FFS. The U.S. EPA considers the groundwater extraction
followed by wetlands, treatment by itself, as exactly what is
happening currently at the creeki.
(g) The reviewer suggests further varieties of the wetland
treatment scheme, but with pretreatment of the
extracted groundwater.
RESPONSE: The U.S. EPA considers a wetland treatment scheme as
inappropriate with the objectives of the FFS and with Little
Bear Creek'• designation as a trout stream.
(4) Conclusions
(a) The reviewer reiterates objections to the FFS and the
Proposed Plan.
RESPONSE: Based upon the responses given to the comments in this
•Review* document and upon the merit of the FFS and Proposal
Plan, U.S. EPA believes it completed a 'proper and thorough
analysis* of all options to meet the objective of the FFS.
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COMMENTS 10t
Document titled 'Cordova Chemical Company of Michigan's
Comments on the Focused Feasibility Study and the Proposed
Plan for the Ott/Story/Cordova Superfund Site' by Cordova
Chemical Company and Fishback, Thompson, Carr & Huber.
(1) There is not justification for conducting an interim
remedy at the site, the air data relied upon as a basis is
flawed.
(a) The FFS does not provide sufficient Justification for
performing a partial groundwater operable remedy. The
only apparent basis for proceeding with the interim
remedy is the MDNR air data.
RESPONSE! U.S. EPA acknowledges Cordova's concerns about the
performance of the FFS. However, we believe that the
proposed remedial actions are justified by the long history
of groundwater contaminant migration into Little Bear Creek
and the unnamed tributary, the degradation of a stream that
at one time was a haven to trout fisherman, and the risks
posed to humans by the volatilization of carcinogenic
organic compounds. As previously expressed in this
document, the U.S. EPA upon review of the Water Quality
Criteria, have noted that several WQC for volatile organics
have been exceeded by contaminants detected during the RI.
The U.S. EPA is concerned about the welfare and peace of
mind of residents in the vicinity of the creeks who are
tired of the delay in actions which would protect them.
(b) The air data is flawed... .
RESPONSE: Please refer to the response to Written Comment 4 which
addresses this issue.
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(c) Cordova disagrees that the ambient air quality in the
vicinity of the unnamed tributary and LBC is accurately
characterized by the arithmetic mean as used in the
Endangerment Assessment. The sampling results are
better represented by a modelled concentration or a
geometric mean and dispersion and vertical
stratifications occur in the vicinity.
RESPONSE: The U.S. EPA believes that results generated by actual field
sampling are far superior to modelled results. The use of
air modelling (see Comment 4 on RSI modelling) has only
confirmed that an excess lifetime cancer risk exists at the
site. The use of the geometric mean on air sampling results
also confirms the U.S. EPA's assertion that there is an
imminent health risk at the site. Using the geometric mean
of data used in the EA, we recalculated the excess cancer
risk poitd by inhalation of volatile organics at the creeks
).
-6
(Benzene: 3.1 x 10 and l,2-dichloro«th*nei 2.7 x 10
As can be seen, this exceeds the *benchmark* of 1 x 10
excess lifetime cancer risk.
(d) Cordova states that the selection of remedy is flawed
because it does not improve the degraded quality of air
in homes caused by the contaminated groundwater flow
underneath the homes.
RESPONSE! The objective of the PFS to prevent contaminated groundwater
from discharging into the creek system, not to prevent air
contamination via vadose zone migration into homes. The
U.S. EPA ie concerned that the volatilization of
carcinogenic organic compounds at the seep and from the
creeks present a serious health hazard justifying this
action.
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(2) The FFS includes a misleading description of the site
history.
RESPONSE: The U.S. EPA notes Cordova's conments. The relevancy of
this history of ownership and who did what is not germane to
the Proposed Plan. U.S. EPA will not comment on the subject
at this time.
(3) The selected Remedial Alternative does not address
stated objectives.
the
(a) Cordova states that none of the criteria of the
objectives are met by the remedial alternative.
RESPONSE: The U.S. EPA would once again like to remind the readers
that, before the shallow aquifer was polluted, it was used
as a potable water source. Although not the primary
objective of the FFS, restoring the shallow groundwater
system to its original, non-carcinogenic state is in the
public interest. By removing contaminants from the source
of the surface water contamination, namely the groundwater
entering Little Bear Creek, the major objective of FFS is
quite sufficiently met. As has been shown in the RI and
reiterated in the FFS, the contaminated groundwater
discharge is placing the resident in the vicinity of the
discharge at unnecessary risk to their health and well being.
RESPONSE}
(b) The FFS does not evaluate how the selected remedial
alternatives satisfies either the first or third
objective as noted.
Cordova Chemical and its consultant have selectively
overlooked the evaluations provided in the FFS. U.S. EPA
recommends review of Appendix A concerning groundwater
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extraction alternatives at Little Bear Creek and the unnamed
tributary. The extraction alternatives clearly meet the
first remedial action objective by intercepting and/or
containing the contaminated groundwater of the unconfined
system. The U.S. EPA. in addressing the third objective,
would like to ask Cordova Chemical how this alternative is
not compatible with potential actions at site? Any
reduction of the amount of contaminants contained in the
voluminous groundwater plume will only help in remedial
efforts. Actions being considered currently in the
development of the site PS must be compatible with the
interceptor at Little Bear Creek in order to be cost
effective, as well as remedially effective.
(4) The PPS does not properly evaluate Remedial
Alternatives and inexplicably eliminates some alternatives.
(a) Cordova believes that additional data is needed in
order to accurately analyze the effectiveness of the
remedial alternatives, residual production,
reliability, administrative feasibility and costs.
Further, sludge generation rates and carbon utilization
rate* are clearly speculative.
RESPONSE: U.S. EPA believes that there is sufficient data available to
proceed with the detailed evaluation of alternatives. We
believe it it not necessary to "reinvent the wheel* each
time an engineered action is to occur. Data concerning most
of the items are available in the literature and through
standard engineering estimation techniques. Treatability
studies have been performed previously on groundwater from
the 0/S/C site. U.S. EPA, as stated, is evaluating the
results of bench-scale testing of the UV-process currently.
U.S. EPA believes that Cordova Chemical expects a detailed
design, at this stage, when in actuality, this is a
feasibility study.
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(b) Cordova Chemical believes the modelling approach in
Appendix A, Groundwater Extraction Alternatives, using
total organic contaminants of groundwater is
inconsistent with Appendix B, Groundwater Treatment
Evaluation.
RESPONSE: The difference in approach used in the Appendices is a
function of their purpose. Appendix A. evaluating the
dynamics of the groundwater system and the impact of the
extraction system, used the total organic contaminant
concentration (not "TOC") because of the extremely large
number of pollutants found in the ground. It is impractical
and unnecessary to model each contaminant separately.
Appendix B, however, evaluated treatment technologies
applicable to the waste stream (contaminated groundwater).
The concentration and mass of the individual contaminants,
as well as their physical/chemical properties, are essential
to the technology evaluation. The U.S. EPA sees no
incompatibilities in the use of each approach.
(c) There is an arbitrary determination to pretreat the
waste for a broader range of organics and to higher
quality than required by the Muskegon County Wastewater
System.
RESPONSEi The U.S. EPA believes that In evaluating the requirement for
treatment (and pretreatment), all applicable discharge
requirements is necessary, as provided in the FFS. As
stated in the NCP, a reduction of the toxicity and volume of
contaminants is necessary. The choice of the treatment
strategy is not arbitrary.
(d) The FFS fails to adequately consider and evaluate
discharge to the POTW.
RESPONSE! Please refer to the response to Written Comment 9.3.b.
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(e) The PFS does not consider land application beyond
biological treatment.
RESPONSE: Land treatment of the waste was initially considered and
screened out in the first screening. Previous experience by
the POTW with 0/S/C wastewater has demonstrated that the
complex organics, namely aniline compounds, are not degraded
in the land treatment system.
(f) Cordova feels the treatment method included in the
selected remedial alternative is questionable because
it does not address metals, inorganics and the
unidentified organics. It appears that the granular
activated carbon will exhaust rapidly and is
economically prohibitive.
RESPONSEt The U.S. EPA believes that metals concentrations are related
to background concentrations. We do not believe that
inorganics in the groundwater will have an effect upon the
proposed treatment scheme. Evaluating a treatment scheme
which will remove and destroy the 'unknown1 contaminants is
definitely a challenge. U.S. EPA believes that the unknowns
will be removed in the proposed treatment scheme. The cost
associated with the use and regeneration of activated carbon
have been considered in the PFS.
RESPONSE!
(S) The selected groundwater purge operation is based on
inadequate data and inaccurate assumptions.
(a) There is insufficient information in the FFS and
supporting documents to justify the simulated purge
rates and the predicted effectiveness of the purge
alternatives.
Please refer to the response to Written Comment 5.10.
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(b) There is no evaluation of the impact of the selected
remedial alternative on the flow of Little Bear Creek,
the unnamed tributary and the surrounding "wetland*.
RESPONSE: The U.S. EPA believes that the evaluation of the impacts of
contaminated groundwater on Little Bear Creek, the unnamed
tributary, and the surrounding 'wetlands* far outweighs the
impacts caused by reduced flow and reduced contaminant
input. The elimination of groundwater discharge in the
unnamed tributary will reduce flow to that supplied by
excess precipitation. The most notable change in the
unnamed tributary will be the reduction in slime growth
associated with the stream pollution. Surface water flow in
Little Bear Creek will be reduced by that attributable to
groundwater discharge. The majority of surface water flow
in Little Bear Creek is associated with upgradient surface
water runoff. The impact of the elimination on the
surrounding wetland must be determined by emperical data.
A baseline study, performed during the remedial design phase
of this action, will evaluate the current status of the
ecosystem on specific ecological end-points to be
determined. As suggested by the U.S. EPA Environmental
Services, the baseline study will be compared to data
generated during the remedial action, taking into account
seasonal variations. The remedial actions are anticipated
to have a positive effect upon the aquatic ecosystem and
surrounding wetland which will be quantifiable.
(c) Cordova Chemical states that the groundwater purge well
concentrations are based upon insufficient data nd
inaccurate assumptions. The modelling programs used
for the evaluation are also inappropriate.
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RESPONSE: The U.S. EPA notes Cordova Chemical's concern about influent
groundvater concentrations and the models used. We,
however, believe that the assumptions and models used in the
FPS to be appropriate for the evaluation of remedial actions
for this site. We believe that Cordova's assertion that
insufficient data is presented for their evaluation is
untrue. Please refer to the response to Written Comment
7.25.
(6) The ARARs Analysis is vague and erroneous in several
respects.
(a) RCRA and Michigan Hazardous Waste Management Act
standards are not applicable because Cordova did not
dispose of any hazardous wastes at the site and
received clean closure certification for its storage
facility in 1987.
RESPONSE: U.S. EPA is in receipt of material included in the
Administrative Record for this site wherein the State of
Michigan specifically lists Acts 64 and 243 as ARARs for the
Ott/Story/Cordova site. U.S. EPA concurs with the State of
Michigan in this regard.
(b) The ARAR's analysis is based upon the erroneous
assumption that the affected aquifers are actual or
potential drinking water sources.
RESPONSEi U.S. EPA reminds Cordova Chemical that before this aquifer
was contaminated by operators of the facility, groundwater
was used at the sole drinking water source. IP it were not
for this reason, local residents would still be using the
groundwater as a drinking supply. We consider these ARAR's
as relevant and appropriate.
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RESPONSE:
(c) The FPS erroneously applies certain state rules as
ARARs.
Please refer to the response to Written Conment 11.6.a. -
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