United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/ROS-90/142
September 1990
&EPA
Super-fund
Record of Decision
Moss-American Kerr-McGee Oil, Wl
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REPORT DOCUMENTATION ' REPOTT NO 2.
PAGE EFA/RCD/R05-90/142
4. Till* >nd Subtitle
SUPERFUND RECORD OF DECISION
Moss-American Kerr-McGee Oil, wi
First Remedial Action - Final
7. AutNx(a)
». Performing Orgainiialion Name and Address
12. Sponsoring Organization N»me and Addrwa
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 2046C
3. Recipient's Accession No.
S. Report Date
09/2-7/90
6.
8. Performing Organization Rept. No.
10. Protecl/Tssk/Work Unit No.
11. Contract(C) or Cntnt(G) No.
(C)
(O
13. Typ» ol Report 1 Period Covered
800/000
14.
15. Supplementary Hotel
16. Abstract (Limit: 200 word*)
The 88-acre Moss-American Kerr-XcGee Oil site, a former wood preserving facility, is in
Milwaukee, Milwaukee County, Wisconsin. The Little Menomonee River, which flows
through the facility, lies within the 100-year floodplain and is included as part of
the site. A section cf the site is wooded, and wetlands are located near the river
onsite and downstream. A 23-acre portion of the site is presently used as a railroad
loading and storage facility for automobiles, and the remainder of the site is an
undeveloped parkland. An ur.cor.fir.ed shallow aquifer underlies the site. Beginning in
1921, operations consisted cf wood preserving of railroad ties, poles, and fence posts
with a mixture of creosote, which is high in PAHs, and No. 6 fuel oil. The facility
changed names and ownership several times until it ceased operations in 1976. Wastes
were discharged to onsite settling ponds until 1971, when wastewater was discharged
into the sanitary sewer system. In 1971, several people received chemical burns
attributed to creosote while wading three miles downstream of the site. This led to a
State order requiring cleanup of onsite settling ponds by the site owner and operator.
In 1973, EPA dredged 5,OOC feet of the river directly downstream of the site. During
1977 to 1978, 450 cubic yards cf contaminated soil were removed during the dismantling
(See Attached Page)
WI
17. Document Analyaia a. Descriptors
Record of Decision - Moss-American Kerr-McGee Oil,
First Remedial Action - Final
Contaminated Media: soil, sediment, gw
Key Contaminants: VOCs (benzene, toluene, xylenes), other organics (PAHs)
b. Identifiers Open-Ended Terms
c. COSATI Field Group
18, Availability Statement
19. Security Claaa (This Report)
None
20. Security Claaa (Thia Page)
Jsjr ne.
21. No. ol Pages
75
22. Price
(S«« ANSJ-Z33.1SI
See Initructiont on Revent
NAL r-OHM 272 (4-77)
(Formerly NT1S-J5)
Department of Commerce
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EPA/ROD/R05-90/142
Moss-American Kerr-McGee Cil, WI
First Remedial Action - Final
Abstract (continued)
of the facility. Studies conducted before 1980 indicated that extensive creosote
contamination was present in the scil and ground water onsite as well as in the
sediment of the Little Menorr.cnee River. This Record of Decision (ROD) provides a
final remedy and addresses source and ground water remediation. The primary
contaminants of concern affecting the soil, sediment, and ground water are VOCs
including benzene, toluene, and xylenes; and other organics including PAHs .
The selected remedial action for this site includes rerouting 5 miles of the river
channel onsite parallel to the existing channel, followed by excavating highly
contaminated sediments from the old channel; mitigating wetland areas; treating 5,200
cubic yards of river sediment, and 80,000 cubic yards of contaminated onsite soil
using onsite soil washing and bioslurry technologies; separation and dewatering of
residues followed by redeposit ion onsite; covering treated material with 2 feet of
clean soil, 6 inches cf tcpscii, followed by revegetation; recycling or treatng
slurry water onsite before discharge tc a publicly owned treatment works (POTW) or
the river; constructing a synthetic geomembrane barrier to prevent movement of
contaminated ground water into the river; collecting ground water using a drain and
interceptor system, followed by treatment using an oil/water separator and granular
activated carbon, with discharge of treated water to a POTW or to the river; removing
pure-phase liquid wastes for cffsite incineration; and ground water monitoring. The
estimated present worth cost for this remedial action is $26,000,000, which includes
an annual O&M cost of S13C,CCO fcr 10 years.
STANDAP^S OP. G~ALS : Goals are designed to reduce the excess lifetime
cancer risk for carcinogens tc iO""1 or less. For non-carcinogens, cleanup levels
will reduce the Hazard Index (HI) to 1 or less. Chemical-specific goals for ground
water include benzene 0.0£"7 ug/1 [State Preventive Action Level (PAL)], toluene
68.6 ug/1 (State PAL), and xylenes 124.0 ug/1 (State PAL). The chemical-specific
goal for soil and sediment is ?AHs (carcinogenic) 6.1 mg/kg (State).
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DECLARATION
for the
RECORD OF DECISION
Moss-American Site, Milwaukee, Wisconsin
Statement of Basis and Purpose
This decision document presents the selected remedial action for
the Moss American Site, in Milwaukee County, Wisconsin, which was
chosen in accordance with the requirements of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980
(CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA) and, to the extent
practicable, the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP). This decision document explains the
factual and legal basis for selecting the remedy for this Site.
The Wisconsin Department of Natural Resources concurs with the
selected remedy. The information supporting this remedial
action decision is contained in the administrative record for
this Site.
Assessment of the Site
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action
selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare,
or the environment.
Description of the Selected Remedy
The selected remedy will be the final remedy at the Site and
addresses three contaminated media, on-site soil, on-site
groundwater, and sediment1 of the Little Menomonee River. The
selected remedy uses treatment to address the principal threats
to human health and the environment posed by conditions at the
Site. The remedy combines source removal and treatment with
containment and short-term site access restrictions, thus
reducing the threats significantly.
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-2-
The major components of the selected remedy include the
following:
Removal and treatment of 5,200 cubic yards of contaminated
sediment and 80,000 cubic yards of soil by on-site
bioremediation, covering remaining soil and treatment
residue for a total of 210,000 cubic yards, on-site.
Rerouting river parallel to existing channel, filling in and
covering existing channel.
Collecting and treating contaminated groundwater.
On-site disposal of residue from treatment of Northeast
Landfill soil in RCRA compliant unit within the area of
contamination.
Specifically, the river will be rechanneled; highly contaminated
on-site soil and sediment from the old river channel will be
excavated and treated by soil-washing and slurry bio-reactor to
health based risk levels of 1 x 10~4 or less. The treatment
residue and low level remaining contamination will be covered on-
site; the old river channel will be covered with soil from th,e
new channel. Extracted groundwater will be treated by oil/water
separator and activated carbon.
Long-Term Management;
The selected remedy provides for continuing monitoring of the
groundwater for at least 5-10 years after the remedial action
is complete. It is anticipated that source removal will reduce
groundwater contamination to acceptable limits within five
years. However, ground-water quality will be evaluated in
increments of 5 years to determine if the remedial action
objectives have been met.
The selected remedy also provides for fencing around the landfill
area, and groundwater monitoring between the old and the new
river channels.
Declaration of Statutory Determinations
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
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-3-
remedial action and is cost-effective. A waiver is justified
pursuant to Section 121(d)(4)(B) for the Subtitle C cap and for
the State double-liner/leachate collection system requirement, on
the basis that an impermeable cap and liner that prevents
flushing of groundwater contaminants will present a greater risk
to health and the environment by prolonging the groundwater
treatment to greater than 200 years. The selected remedy will
comply with the Land Disposal Requirements (LDRs) through a
Treatability Variance for the contaminated soil and debris.
This remedy utilizes permanent solutions and alternative
treatment technologies to the maximum extent practicable, and it
satisfies the statutory preference for remedies that employ
treatment that reduce toxicity, mobility, or volume as their
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.
Regional Administrator
/0ate/'
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RECORD OF DECISION
ROD SUMMARY
Moss-American Site
Milwaukee, Wisconsin
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TABLE OF COOTP7IS
1. Site Description 1
2. Site History ard Enforcement Activities 2
3. Highlights of Coramunity Participation 3
4. Scope and Role of Response Action 4
5. Summary of Site Characteristics 5
6. Summary of Site Risks 6
1. Description of Alternatives 13
8. Summary of Conparative Analysis of Alternatives 26
9. The Selected Remedy 34
10. Statutory Determinations . 39
11. Documentation of Significant Changes 45
12. Responsiveness Summary 47
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FIGURES and TARIFF
Figures
1. Location Map 1
2. Existing Conditions 1
3. 100-Year Flood Plain 1
4. Historical Land Use 2
5. Extent of Soil and Groundwater Contamination 5
6. Sum of Carcinogenic PAHs in Sediments 6
7. Permanent River Relocation 15
8. Alternative 2 15
9. Recommended Groundwater Remedial Action 16
10. Alternative 3-A 17
11. Slurry Bioreactor Conceptual Process Flow Schematic 18
12. Alternative 3-B '22
13. Conceptual Cross Section of Land Treatment Bed 22
14. Alternative 6 25
Tables
1. Potential Contaminants of Concern 7
1-a. Potential Carcinogens 9
l-b. Exposure Assumptions 11
1-c. Summary of Onsite Trespass Risks 11
1-d. Summary of Residential Development Risks '. 12
1-e. Summary of Recreational Use Risk, River 12
2. Water CMality-Based Effluent Limits 16
3. Treatment Levels for the LDR Treatability Variance 19
4. Sediment Quality Criteria 28
5. Estimated Cost of Remedial Action 33
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1. Site Description
The eighty-eight acre Moss-American Site includes the former
location of the Moss-American creosoting facility, five miles of
the Little Menomonee River, a portion of which flows through the
eastern half of the site, and the adjacent flood plain soils.
The Site is located in the northwestern section of the City of
Milwaukee, County of Milwaukee, state of Wisconsin, at the
southeast corner of the intersection of Brown Deer and Granville
roads, at 8716 Granville Road. See Figure 1 for a location map
of the Site. Sixty-five acres of the Site are undeveloped
Milwaukee County park land. Twenty-three acres are owned by the
Chicago and Northwestern Railroad and used as an automobile
loading and storage area. Figure 2 shows current Site use.
The Little Menomonee River, portions of which are defined as part
of the Site, flows through the northeastern portion of the Site,
continuing on through the Milwaukee County Parkway, to the
confluence of the Menomonee River about five miles to the south.
The Little Menomonee River is included in the Milwaukee Estuary
and the Menomonee River Remedial Action Plans (RAP) by virtue of
its inclusion in the Menomonee River watershed. The river is
classified INT-D, which means that it is considered suitable for
intermediate (tolerant) fish and aquatic life. The Site is
located in a moderately populated suburban area of mixed
industrial, commercial, residential, and recreational use. South
Eastern Wisconsin Regional Planning Commission (SEWRPC) estimates
the population at 2,036 persons per square mile. The nature of
current Site and area uses is not expected to change in the near
future.
The Milwaukee County Soil Survey classifies the developed areas
on the Site west of the river as loamy land, land consisting of
fill or cut and borrow areas. The wooded areas on both sides of
the river consist of a poorly drained silty soil underlain by
stratified lacustrine silt and very fine sand. The soil is
moderately permeable with high available water capacity.
Approximately one-quarter of the Site is in the 100-year flood
plain as shown in Figure 3.
The Site overlies a surficial, low yield, Class II aquifer above
a confining bed of dense silty clay till. The confining bed is a
minimum of 40 feet thick and could be as thick as 120 feet.
Below the confining bed lies the regional dolomite aquifer. The
saturated thickness above the till is between 5 and 15 feet.
Groundwater flows at a rate of seven feet per year from west to
east, discharging into the river at an average rate of 8,500
gallons per day. Depth to groundwater varies from zero feet in
the wetlands near the river, to about 12 feet further west on the
Site. The groundwater is not currently used as a source of
drinking water; local residents are connected to a municipal
system.
Elevations at the Site range from 714 to 750 feet. The river
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MOSS-AMERICAN
SITE
BROWN DEER ROAD
GOOD HOPE\ ROAD
FIGURE 1
LOCATION WAP
MOSS-AMERICAN FS
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u h _>.>. v- \
FENCE SUnnoUNDINO
CAR STOMAQE AREA
GRAVEL
FILL
(LIMESTONE!
SITE OOUNOAMY
ICOMf RETE BLAM,
600
SCALE IN FEET
FIGURE 2
EXISTING CONDITIONS: 1987
MO53-AMEniCAN FS
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t A|)urtinur>| i
' ', ' -- -..: - .^ACp ft NORTHWEST,^ ((
• rrtioiiMATE
SCAU IN rr.ET
FIGURT 3
100 • VFAR FLOOD PLAIN
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drains the entire Site, running adjacent to the facility for
about 2,100 feet. Typical base flow water depth of the Little
Menomonee River is 1 to 2 feet, with a corresponding width of
about 20 feet. Flow rate is estimated at an average annual of 10
- 17 cubic feet per second, with a peak rate of 330 - 770 cubic
feet per second. The sediment is typically silt or clay in
composition, soft in some areas and hard packed in others.
2. Site History and Enforcement Activities
In 1921, the T. J. Moss Tie Company established a wood preserving
facility on twenty-three acres of the Site west of the Little
Menomonee River. The plant preserved railroad ties, poles, and
fence posts with creosote, a mixture of 200 or more chemical
compounds derived from coal tar and fuel oil. The process used a
50/50 mixture of creosote and No. 6 fuel oil. There is no
indication that any other chemicals were used at the facility.
Kerr-McGee purchased the facility in 1963 and changed the
facility's name to Moss-American. The name was changed again in
1974 to Kerr-McGee Chemical Corporation—Forest Products
Division.
From 1921 to 1971, the facility discharged wastes to settling
ponds that ultimately discharged to the Little Menomonee River.
These discharges ceased in 1971 when, in response to a City of
Milwaukee order, Moss-American diverted its process water
discharge to the Milwaukee sanitary sewerage system. The
facility closed in 1976. The eastern part of the property was
acquired by Milwaukee County in 1978; Chicago and North Western
Railroad bought the western parcel in 1980. Figure 4 shows
historical Site uses.
State and national attention came to the Site in 1971 when young
people, engaged in an Earth Day clean up of the river, received
chemical burns from a tarry substance while wading more than
three miles down river from the Site. Sampling results indicated
that the tarry substance was creosote and that the Moss-American
facility was the source of the contamination.
Subsequently, under a Wisconsin Department of Natural Resources
(WDNR) order, Kerr-McGee cleaned the eight settling ponds and
dredged about 1,700 feet^of river to remove creosote-contaminated
soil and sediment. The settling ponds were filled with clean
soil, the discharge pipe to the Little Menomonee River was
removed and a twelve foot deep underground clay retaining wall
constructed between the ponds and the river, adjacent to the
facility.
In 1973, United States Environmental Protection Agency (U. S.
EPA) financed the dredging of approximately 5,000 feet of river
between the Site and Bradley Road. As Figure 4 shows, most of
the dredged sediment were contained on Site in the Northeast
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t f
\, \ /
\\ . GRAVEL Fill /
MlSTOniCAL LAUD
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Landfill area and along the west bank of the river.
In 1974, U. S. EPA (under the Clean Water Act) and Milwaukee
County filed a complaint seeking an injunction against Kerr-McGee
Chemical Corporation, and to recover costs incurred for studies
and cleanup. In 1978, the lawsuit was dismissed due to the
discovery that some of the data had been falsified. Milwaukee
County reached a settlement with Kerr-McGee in which it received
a major portion of the property. This property was added to the
existing county park corridor along the Little Menomonee River
south of the Site.
Between 1977 and 1978, the Southeast District of the Wisconsin
Department of Natural Resources (WDNR) regulated the disposal of
demolition waste from the facility as it was dismantled by the
company. This resulted in the removal and off-Site disposal of
450 cubic yards of creosote-contaminated soil.
The water quality and soil/sediment contamination studies done by
U.S. EPA and other agencies between 1970 and 1980 indicated that
gross creosote contamination was present in the soil and
groundwater at the facility as well as in the sediment of the
Little Menomonee River. In 1983, the facility was placed on_the
National Priorities List (NPL) pursuant to Section 105 of the
Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA), 42 U.S.C. Section 9605 with a Hazard Ranking Score
(HRS) of 32.14.
In April of 1985, notice letters were mailed to the potentially
responsible parties (PRPs) which included Kerr-McGee, Chicago and
Northwestern Railroad, and Milwaukee County, inviting them to
negotiate for the conduct of the Remedial
Investigation/Feasibility Study (RI/FS) at the Moss-American
Site. All three PRPs attended the meeting held 8/22/85 but
declined to undertake the RI/FS. Under an existing remedial
contract, U. S. EPA assigned the consulting firm of CH2M Hill the
RI/FS project, which began in 1987. The RI report was completed
in December 1989 and the FS approved in May 1990.
3. Highlights of Community Participation
In October 1987 U.S. EPA hosted a "kickoff" availability session
at Vincent High School in Milwaukee. This informal session was
designed to talk with people in a one-on-one situation about the
pending start of the RI/FS. A community relations plan was
finalized in November 1986. Fact sheets were developed for and
distributed to the community in October 1987, Spring 1988, and
May 1990.
The RI Report was released to the public in December 1989. The
public was informed through a Fact Sheet that summarized the
findings of the RI and invited comments. No comments were
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received. The FS Report and the Proposed Plan for the Moss-
American site were released to the public for comment on June 4,
1990. These two documents were made available to the public in
both the administrative record and an information repository
maintained at the U. S. EPA Docket Room in Region V and at the
Mill Road Library, located at 6431 North 76th Street, Milwaukee,
Wisconsin. The notice of availability for these two documents
was published in the Milwaukee Journal on May 25, 1990. A public
comment period on the documents was held from June 4, 1990 to
July 5, 1990 and extended to August 6, 1990.
In addition, a public meeting was held at Vincent High School on
June 21, 1990. Twenty nine people attended the meeting. Those
in attendance were members of the media, representatives from
Kerr McGee, Chicago and Northwestern Railroad and Milwaukee
County, the potentially responsible parties (PRPs), vendors of
various remedial technologies, State Representative Tom Barrett,
and eight to ten residents of the area. At this meeting,
representatives from U.S. EPA, Wisconsin Department of Natural
Resources (WDNR), and the Department of Health answered questions
about the Site and the remedial alternatives under
consideration. A response to the comments received during this
comment period is included in the Responsiveness Summary, which
is part of this ROD.
The public participation requirements of CERCLA sections 113 (k)
(2) (B) (i-v) have been met in the remedy selection process.
This decision document presents the selected remedial action for
the Moss-American Site, in Milwaukee, Wisconsin, chosen in
accordance with CERCLA, as amended by SARA and, to the extent
practicable, the National Contingency Plan (NCP). The decision
for this Site is based on the administrative record.
4. Scope and Role of Response Action
As with many Superfund sites, the problems at the Moss-American
Site are complex. Remediation at the Site addresses three
contaminated media, on-site soil, on-site groundwater, and
sediment of the Little Menomonee River. A possible fourth
contaminated media, the downstream portion of the flood plain not
included in the soil remedial action, will be investigated
further in the predesign phase. If sampling indicates that
contamination is present above risk levels, it will be addressed
as part of this response action. This response action will be
the final remedy at the Site.
This remedial action addresses the principal threats to human
health and the environment posed by conditions at the Site. The
threats to human health and the environment come from direct or
indirect exposure to Site contaminants in on-site soil or
sediment, by direct contact, inhalation, or ingestion.
Groundwater, while presently not a source of drinking water, is a
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continuing source of contamination to the river. The remedy
combines source removal and treatment with containment and short-
term Site access restrictions, thus reducing the threats
significantly.
Specifically, the river will be rechanneled; highly contaminated
on-site soil and sediment from the old river channel will be
excavated and treated by soil-washing and slurry bio-reactor to
health based risk levels of 1 x 10~4 or less. The treatment
residue and low level remaining contamination are covered on-
site; the old river channel is covered with soil from the new
channel. Extracted groundwater will be treated by oil/water
separator and activated carbon.
The selected remedy provides for continuing monitoring of the
groundwater for 5-10 years after the remedial action is
complete. It is anticipated that source removal will reduce
groundwater contamination to acceptable limits within five
years. However, ground-water quality will be evaluated in
increments of 5 years to determine if the remedial action
objectives have been met. Target compounds for groundwater are
the B-E-T-X compounds: benzene, ethylbenzene, toluene, and
xylene. The groundwater cleanup standards are the preventative
action limits (PALs) for B-E-T-X compounds established by the
State of Wisconsin and described in Section 7.
5. Summary of Site Characteristics
The RI confirmed that polyaromatic hydrocarbons (PAHs),
components of creosote, are the major contaminants at the Site.
Creosote is a coal tar distillate containing over 200 different
compounds, but predominantly composed of PAHs, multi-ringed
organic chemicals. These contaminants contain a Resource
Conservation and Recovery Act (RCRA) listed waste, K001 and U051,
Figure 5 shows the extent of soil and groundwater contamination.
5.1 On-site Soil
The RI determined that, while low levels of contamination are
found throughout the on-site soil on the west side of the river,
roost of the contamination is focused in the former use areas:
the processing area and vicinity, the settling ponds, the
treated storage areas, the southeast landfill, and the northeast
landfill, an isolated area on the east side of the river. PAH
levels as high as 3.2% were found in these areas, and, in
addition, free product was observed in some test pits. Benzene-
Toluene-Xylene (BTX) levels range from .02 to 17 ppm.
Contamination is greatest in the upper 10 feet of soil but may
extend down as far as 20 feet. Additional sampling will be
necessary during predesign to further define both extent and
depth of contamination.
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fnduutry
Fluid
Wnflnml
Uusirlnnttfil Aoortmnnl1)
-.._ *°"o
OBSERVED AREAL
EXTENT Of SOIL
CONTAMINATION \
f/irni n.'l.l
NORTHEASf
UANOFILL '
AREA,'
LEGEND
• — — SITE BOUNDARY
I OISS
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5.2 Groundwater
The nature and extent of groundwater contamination was defined
at the Site through the placement of shallow, intermediate and
deep wells. Contaminants were detected only in the shallow
wells, no contaminants were detected deeper than 20 feet.
Contaminants found in the groundwater are polyaromatic
hydrocarbons (PAHs) and BTXs. Free product was found in two
monitoring wells near the settling pond area; CPAH concentration
in the oil phase of the sample was almost 12%. Additional deep
monitoring wells will be placed during design to monitor the
quality of the regional aquifer. The contaminated plume is
approximately 600 feet across, extending about 100 feet from the
pit and ditch area east to the Little Menomonee River.
Groundwater flow is from west to east, into the Little Menomonee
River, at a rate of 3,000 to 14,000 gallons per day.
5.3 Surface water of the Little Menomonee River
The surface water of the Little Menomonee River does not appear
to be contaminated. No PAH or volatile organic compound (VOC)
values exceeding background were detected. No visible evidence
of surface water contamination was noted during the sampling.
Oil sheens have been observed when sediments are disturbed,
however. This is to be expected, since most PAHs have low
solubility in water and would normally sink to the river bottom.
VOCs would volatilize.
5.4 Sediment of the Little Menomonee River
Contaminants detected in the sediment were similar to those
detected in the soil, with PAHs being the primary contaminants of
concern. Sediment contamination exceeding background (currently
estimated at 18 ppm CPAHs) was found fairly evenly distributed
throughout the five mile reach of the river between the Site and
its confluence with the Menomonee river. Refer to the FS,
Appendix J, for the sediment background sampling method and the
data obtained. PAH levels in the sediment were as high as 5900
ppm and CPAH levels as high as 500 ppm. Figure 6 compares the
sediment CPAH levels in each segment of the Little Menomonee
River.
6. Summary of Site Risks
As part of the RI, a baseline risk assessment was conducted for
the Moss-American Site. A baseline risk assessment evaluates
actual and potential threats to human health and the environment
posed by a site in the absence of any remedial action. It
identifies and characterizes the toxicity of contaminants of
potential concern, potential exposure pathways, potential human
and environmental receptors, and the extent of expected impact or
threat under the conditions defined for the site.
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SAWPLI NO. AND LCX;AT10N (If more then on« temple
token o". c sample location, concent/'otlon la U^e
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IML£T SAMPLE NO. AND LOCATION
C NOT DETCCTLT AT DETECTION UWIT INOICATtD
FIGURE 6
SUM OF CARCINOGENIC
PAHs IN SEDIMENTS
MOSS-AMERICAN FS
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The chemicals of concern at the Site, those the Risk Assessment
is based upon, are eight CPAHs. The CPAHs of concern at the Site
are:
benzo[a]anthracene
benzo[b]fluoranthene
benzo[a]pyrene
dibenzofa,h]anthracene
6.1 Exposure Assessment
chrysene
benzo[k]fluoranthene
indeno[1,2,3-cd]pyrene
benzo[g,h,i]perylene
The Risk Assessment determined that exposure to the chemicals of
concern and other Site-related contaminants in soil and sediment
can occur through three exposure pathways: direct contact,
direct or indirect ingestion, and inhalation of suspended
particles. Exposure scenarios were developed to describe
potential human exposures, via these pathways, under current Site
conditions and future potential Site uses. Potential effects on
the environment were also evaluated.
The Risk Assessment concluded that actual or threatened releases
of hazardous substances from this Site, if not addressed by
implementing the response action selected in this ROD, may
present an imminent and substantial endangerment to public
health, welfare, or the environment.
6.2 Contaminant Identification
Seventy chemicals on the U.S. EPA's Target Compound List (TCL)
were detected at the Moss-American Site. From the 70 chemicals
detected, a subset were identified as contaminants of potential
concern for use in the baseline risk assessment. Table 1 lists
contaminants of potential concern. Chemicals were selected
primarily on the basis of having available toxicity values (i.e.,
cancer potency factors and reference dose values) and
environmental media standards and criteria. Additional chemicals
were included based on factors including toxicity, frequency of
detection, concentration, and environmental fate.
6.3 Toxicity Assessment '
The toxicity assessment addressed both the potential human health
and environmental effects associated with the chemicals of
potential concern.
Carcinogenic Risk: 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)~1, are multiplied by the estimated intake of
a potential carcinogen, in mg/kg-day, to provide an upper-bound
-------
Table 1 (Page 1 of 2)
Potential Contaminants of Concern and Criteria for Selection
Moss-American Site
Selected based
CHEMCAL on critical Selected based on Selected based on
toxicity values toxicity concerns other factors
Acenaphthene d
Acenaphthylene d
Acetone a
Anthracene d
Antimony a
Arsenic b
Barium a
Benzene b c
Benzo[a]anthracene c
Benzo[bjfluoranthene c
Benzo[k]fluoranthene c
Benzo[g,h,i]perylene
Benzo[a]pyrene a
Benzoic Acid a
Beryllium a
bis(2-Ethylexy1)phthalate a/b
2-Butanone a
Cadmium a/b
'Chlorinated dio>dns and furans f
Chloroform a/b
Chromium a/b
Chrysene d
Copper a
Creosote b e
Dibenz[a,h]anthracene c
Dibenzofuran d
1,1-Dichloroethane a/b
2,4-Dinitrophenol a
EthyLbenzene a
Fluoranthene d
Fluorene d
Indeno[1,2,3-cd]pyrene c
Lead a
Manganese a
Mercury a
Methylene chloride a/b
Naphthalene a
Nickel a
Phenanthrene d
Phenol a
Pyrene d
-------
Table 1 (Page 2 of 2)
Potential Contaminants of Concern and Criteria for Selection
Moss-American Site
Selected based
CHEXrCAL on critical Selected based on Selected based on
toxicity values toxicitv concerns other factors
Styrene a
2,3,7,8^TCDD b
Toluene a
1,1,l-Trichloroethane a
Vanadium a
Xylenes a
Zinc a
a. Selected based on having a reference dose value.
b. Selected based on having a cancer potency value.
c. PAHs selected based on potential carcinogenicity.
d. Selected based on frequency of occurrence and relative abundance.
e. Creosote selected because it is the major source material.
f. Dioxins and furans selected based on toxicity.
-------
8
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 or chronic animal
bioassays to which animal-to-human extrapolation and uncertainty
factors have been applied.
Noncarcinoqenic Risk: 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.
6.4 Human Health Effects
The main health effects associated with the major chemical
groups found at the Site are:
Creosote—exposure to creosote liquid or vapor may produce
skin irritation and ulceration, increased salivation,
vomiting, and respiratory difficulties. Some of the PAH
components are known to be carcinogenic.
Polyaromatic hydrocarbons—PAHs, a primary component of
creosote, have been associated with lung, stomach, and skin
cancers. Carcinogenicity has been associated with the 4-
and 5-ring PAHs such as benzo[a]pyrene. Some
noncarcinogenic PAHs appear to enhance the carcinogenic
potential of the carcinogenic PAHs.
BTX Compounds—Benzene is a human and animal carcinogen
associated with leukemia. Toluene and xylene cause
depression of the central nervous system.
Phenolic Compounds—Phenolic compounds are corrosive to
skin and cause severe systemic poisoning.
Inorganic Chemicals—Arsenic is a known human skin and lung
carcinogen. Cadmium is associated with respiratory and
kidney toxicity as well as prostate and lung cancer. Lead
is toxic to the nervous system, blood, and cardiovascular
-------
system. Zinc is associated with fever, nausea, and stomach
disturbances.
Twenty of the contaminants detected at the Site are classified as
known (class A), probable (class Bl and B2), or possible (class
C) human carcinogens by the U.S. EPA Carcinogen Assessment Group
(Table 1-a).
6.5 Environmental Effects
Exposure of birds, terrestrial wildlife, and aquatic plants and
animals can occur through direct contact, or ingestion of
contaminated surface soil or contaminated sediment of the Little
Menomonee River. PAHs were the primary focus of the
environmental effects evaluation because of their abundance in
the soil and sediment at the Moss-American Site. In general, the
information based on the environmental effects of PAHs is not
very extensive. There are no promulgated standards or criteria
for PAHs designed for the protection of aquatic organisms or
terrestrial wildlife.
However, PAHs that are carcinogenic to mammals are generally also
carcinogenic to fish. In many cases, aquatic organisms from PAH-
contaminated environments have a higher incidence of tumors and
hyperplastic disease than those from nonpolluted environments. A
growing body of evidence, mostly circumstantial, links PAHs to
cancer in fish populations, especially bottom dwelling fish from
areas with sediment heavily contaminated with PAHs. The State
of Wisconsin has developed Sediment Quality Criteria (SQC) for
the Little Menomonee River based on the equilibrium partitioning
approach. The SQC, shown in Table 4, set a level of 3 ppm for
CPAHs in sediment. This equates to a human health risk of
approximately 1 x 10~*>.
Data are unavailable on acute and chronic toxicity for avian
wildlife, reptiles, or amphibians. Numerous PAH compounds are
distinct in their ability to produce tumors in the skin and most
epithelial tissues of animal test species. These effects are
likely a concern for mammalian wildlife exposed to PAHs.
6.6 Public Health Risk Characterization
This section summarizes the results of the risk characterization.
It includes the quantified carcinogenic risks for each
contaminant of concern in each exposure medium for each exposure
pathway; the combined carcinogenic risks reflecting all
contaminants and pathways reasonably expected to affect a given
population; and the potential for noncarcinogenic effects as
identified by the hazard quotient for each contaminant of concern
in each exposure medium for each exposure pathway.
-------
10
Table 1-a
POTENTIAL CARCINOGENS
U.S. EPA Carcinogen Assessment Group Classification (a)
CHEMICAL
Arsenic
Benzene
Benzo [ a ] anthracene
Benzo[b] f luoranthene
Benzo [k] f luoranthene
Benzo[a]pyrene
Beryllium
bis(2-Ethyhexyl)phthalate
Cadmium
Chloroform
Chromium (hexavalent)
Chrysene
Creosote
1, 1-Dichloroethane
Indeno[l,2, 3-cd]pyrene
Methylene Chloride
Nickel
N-Nitrosodiphenylamine
Tetrachloroethene
Inqestion
A
A
B2
B2
B2
B2
D
B2
D
B2
D
B2
Bl
C
C
B2
D
B2
B2
Inhalation
A
A
B2
B2
B2
B2
B2
D
Bl
D
A
B2
Bl
D
D
B2
A
D
B2
(a) U.S. EPA Carcinogen Assessment Group Classification (IRIS
database 2-1-1988)
A: Human carcinogen - Sufficient evidence from epidemiological
studies.
Bl: Probable human carcinogen - Limited evidence of
carcinogenicity to humans.
B2: Probable human carcinogen - Sufficient evidence in animals
and inadequate or no human evidence.
C: Possible human carcinogen - Limited evidence in animals
and the absence of human data.
D: Not Classified - Inadequate or no evidence to classify.
-------
11
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., 1 x 10~6 or 1E-6). An excess lifetime cancer risk of 1 x
10~° 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.
Based on the exposure assessment, three exposure scenarios were
defined to describe potential human exposures for current Site
conditions and potential future uses. The exposure scenarios
used to evaluate the health risks from the Moss-American Site
were:
Current conditions—site trespass scenario
Current conditions—river recreational use scenario
Potential future use—residential development scenario
The exposure assumptions associated with each of these scenarios
are detailed in Table 1-b. For each scenario two sets of risk
estimates were made. One evaluated risks based on the highest
detected concentrations, and the other estimated risks based on
geometric mean concentrations. For evaluation purposes, the
Site was divided into areas either east or west of the Little
Menomonee River.
1. Current conditions—site trespass scenario, soil
The risks associated with Site trespass are summarized in Table
1-c. Excess lifetime carcinogenic risks from soil ingestion for
the eastern portion of the Site range from 3 x 10~4 (based on
the highest detected concentrations) to 5 x 10~^ (based on mean
concentrations). Excess lifetime carcinogenic risks from soil
ingestion for the western portion of the Site range from 5 x 10~4
(based on the highest detected concentrations to 2 x 10~5 (based
on mean concentrations). The CPAHs are the major chemicals
contributing to the risks.
Inhalation exposures for both portions of the Site have risks
less than 1 x 10-7. A comparison of estimated intakes to RfDs
indicated that no RfDs were exceeded in any situation evaluated.
-------
Table 1-b
EXPOSURE ASSUMPTIONS
MOSS-AMERICAN SITE
Targe! Receptor
Trespass Setting
Child
Adult
Individual used tor
liletime cancer risk
estimate
Child
Adult
indivtdua' use-3 to-
lifetime cancer risk
estimate
Residents' Settinc
Toddler
Adult -
Individual used for
lifetime cance' risk
estimate
Recreational Setting
Child
AOull
Individual USe-3 lor
lifetime cancer risk
Route
Ingesiion
Ingestion
Ingesiion
Inhalation
Initiation
Inhalation
Ingestion
Ingestion
Ingestion
ingestion
Ingestion
Ingestion
Intake Rate
0.1 g/day
O.i g/day
O.i o/day
13 l/min
20 I/mm
20 l/min
0.2 g/day
O.i a/day
Age 1-5:
0.2 g/day
Age 6-70:
O.i g/day
O.i g/day
O.i g/aay
O.i g/day
Body Weight
35-kg
70-kg
70-kg
35-kg
70-kg
70-kg
15-kg
70-kc
70-kg
35-kg
70-kg
70-kg
Frequency
-
-
40days/yr
lOyrs
-
-
2 hr/day
<0 days/y:
10 yrs
-
-
365 days/y
70 yrs
-
-
40days/yr
10 ys
estimate
-------
Tnl -c
Summary o( Onsile Trospnss Risks
Moss-Amcricnn Sitn
Noncarcinogonic Risk*
POKIIIO Target
r-otlmg Concnnlfmion Population
Ingwrrtlpn
Ha/nrd Index
Inhnlftlton
Havnrrt Indoir
Chemicals
Ejccoodmg RfD
Dnloctod
fioomol'ic
Child
Child
0 15
0 I 1
0 M
0 OM
Nnno
Mono
Cfl'rinogonic
Tolnl IngoKlion
F^ircofin IJInlimo
Cnnror Hink
Cnrcinoflonic
Mnjoi ChomicnU
Totnf Inhalation
Excotifi Lifntimo
Cnnror Flifik Mnjnr I
Arlull
0 073
0012
Mono
PAIUfn)
Goomotr ic
Mo.ln
Adult
0055
0 01 1
Nonn
PAH«(n|
4F-08
PAMi=(n)
Highosl
Doioctod
Goomolric
Monn
HiQhosl
Doioctod
Mopn
Child
Child
Adult
Adult
2 4
0 24
1 2b
0 12
0023
0 008
0018
0006
Nono
Nono
Nono
2F-05
PAHR(n)
PAHB(«)
3E-06
1E-07
PAHs(a)
PAHs(n)
F»posu'o Aisuniptions
No'ic.iicinogonic Risks - 35 kg body weigh! (child). 70 kg body weight (ndull). 0.1 g'dny soil Inloko
ctiMd inli^lnhon rnto 1 3 l/min. Adult inhalation rule 20 l/mtn
Cmcinoqonic nisks- 70kghody weight. 0.1 g/day soil intake. 2-dfly/wk. 20-wks/yr. 10 yonrs
.1 PAHs inrliido hon;o|a|anthtacone. ben7o|b|lluoi(inthene. ben?o|k|nuocanthone. bon;o|a|pyrono. bon/o|g.h.i|porylono
rh»y;nno dihon7|a.h|anlhfacono. indeno|l.2.3-cd|pyfene
h fIn ifu)ivn1iint rhomical inlako oirceods RFQ Whon ha;ard
(ri'fi>«M-. .mi iii-oMiiii.-iiod hy lin.Tllh ol'oci. no suhmdo*os owceod 1
-------
12
2. Potential future conditions—residential development,
soil
The risks associated with Residential Development are summarized
in Table 1-d. Excess lifetime carcinogenic risks from soil
ingestion for the Site east of the river range from 2 x 10~2
(based on the highest detected concentrations) to 2 x 10~4
(based on mean concentrations). Excess lifetime carcinogenic
risks from soil ingestion for the Site west of the river range
from 4 x lO"^ (based on the highest detected concentrations) to 3
x 10~4 (based on mean concentrations). The carcinogenic PAHs are
the major chemicals contributing to the risks from the Site.
RfDs for lead, cadmium, and 2,4-dinitrophenol, based on highest
detected concentrations, were exceeded for a child's soil
ingestion exposure scenario with a HI of 12.
3. Current Conditions—River Sediment Exposures
The risks associated with river sediment are summarized in Table
1-e. The river was divided into five 1-mile segments (i.e.,
river miles) to better characterize the risks associated with
exposure to individual river locations and are limited to
trespass exposure (most likely to children) resulting from
recreational use of the river. Exposure could result form
inadvertent ingestion of sediment or direct dermal contact.
Carcinogenic PAHs were detected in all segments of the river and
contributed the most to the excess cancer risk levels. Estimated
excess cancer risk levels from ingestion exposures based on the
highest detected concentration ranged from 1 x 10~4 for river
mile 1, to 3 x 10~5 for river mile 5. Cancer risk estimates for
average concentrations were greater than 1 x 10~6 for all
downstream segments. No RfD values were exceeded for
noncarcinogenic exposure at any river mile segment.
The effects of acute dermal exposure to creosote are also a
concern, although this risk cannot be expressed quantitatively.
Skin irritations resulting from contact with sediment have been
documented and are assumed to still exist.
The baseline risk assessment is based on a variety of factors
including:
Sampling and analysis
Fate and transport estimation
Exposure estimation
Toxicological data
Possible synergistic/antagonistic effects
Additional routes of exposure
-------
Table 1-d
Summary o' Residential Development Fli.skr>
Moss-Americ.in Silo
frxpoturfl
f-ollinQ
Fnsl
WnsI
Coficontmlloo
Highnst
Ooloclod
Geometric
Mono
Hlghosl
On'nclod
Goomfllric
Moan'
Highosl
Dolocled
Gsomoltlc
Moan
Higheel
Ooloclsd
Goomol'lc
Menn
Noncfl'cinognnic nii;kf) Cnfcinogonic nifikfl - IngoRtion
Totnl IngoMino
Tnrgnl Ingofition Chomir.nU Ercond tlfolime
Populntino Mn/flrd Indn* Twrooding RfT) Cnnco* Rink Mnjoc ChomicnU
Child 0 !>? Mono
Cluld 0 19 Mono
Adult 0 099 Mono ?P-02 PAHB(n)
AduM 0051 Nonn JE-04 PAHs(n)
Child 1? CndfTiium. lond
?.f>n/o|
cdtysooo. d'bon7|e.b|anlh»acene, lnd«no| 1.?.3-cd|pyrono
) Mo individual chomic«l intake exceeds HFO When ha;aid
mdoiros ato ro-oslim.ilod by heallh ellncl. no Gubindoros oxcood I
j h,i|pnt y
-------
Table 1-e
Summary of Recreational Use Risks
Linie Menomonee River
Sueam Mile Concentration
i Hignesi
Detected
Geomeinc
Mean
Highest
Detected
Geometric
Mean
Hignes:
2 Detected
Geometric
Mean
Hignes:
Detected
Geometric
Wear.
Highest
: Deiectec
Geometric
Mean
Highest
Dei ec tec
Geometric
Mean
Highest
t Detected
Geometric
Mean
Highest
Detected
Geometric
Mean
Highest
i Detected
Geometric
Mean
Hignes:
Detected
Geometric
Mean
Targe'
Population
Child
Child
Adult
Adult
Child
Chile
AOJI:
Aaji:
Child
Child
Adui:
Aduii
Child
Cnilo
Adui:
AOul!
Child
Child j
AOull
Adult
Noncarcinogenic
Ingesiion
Ingesiion
Risks -
Chemicals
Hazard Index Exceeding RfD
0.46
0.16
0.20
0.08
0.21
O.i<
0.10
0.07
0.32
0.26
0.16
0.13
.0.12
0.23
0.06
0.12
0.56
0.47
0.30
0.23
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
Carcinogenic R:sKs - Ingestion
Excess Lifetime
Cancer Risk. Maior Chemicals
-
-
lE-CW PAHS (a)
3E-05 PAHs(a)
-
-
lE-CX PAHs (a)
2E-0; PAHs (a
~
.
1E-CW PAHs(a)
2E-05 PAHs (a)
-
-
5E-05 PAHs (a)
5E-06 PAHsU; -
-
°
-
3E-05 PAHS (a;
3E-06 PAH.sU;
Exposu'6 AssumpnonE
Nonca'Cino^enic Ritke - Chile 35 kg bofly weigh! 0 1 g/flay toil inlake
- Aoul: 70 kj boCy weigni 0 i g;0ay toil intake
Carcmogeni: RISKS - 70 »g t>°Qy ~eig.ru. 0 i a/day soii miaKe
Exposure dotation 2 dayi/weet to.' 20 v»eeki/yea< 10 yea-6
a FA>isin;uaeDen?o
-------
13
Within the limits of these assumptions and factors this risk
characterization presents a conservative representation of the
present and future potential for risk to public health and the
environment posed by the contaminated soil, groundwater and
sediment.
7. Description of Alternatives
The FS, based on information gathered during the RI, evaluated
and screened a wide range of possible technologies to be
considered for the final step of the FS process called the
detailed evaluation of alternatives. The technologies were then
combined into site specific alternatives. The FS identified and
evaluated seven alternatives including a no action alternative.
The option of on-site disposal of the treatment residue from the
Northeast Landfill area was not evaluated in the FS and has been
included in the treatment alternatives to accommodate Wisconsin's
Hazardous Waste Capacity commitment. Soil and sediment volumes
given in the description of alternatives are in-place volumes and
correlate to the volumes described as "highly contaminated" in
the FS.
-------
14
1 . No action
2 . Reroute river
. Cover ccntaminated sediitiait in
. Cover ccntaminated soil
. Collect and treat ccntaminated grcundwater
. Remcve contaminated soil in Northeast Landfill, incinerate
off-site
3A . Remove and treat highly contaminated sediment and soil in
an on-site slurry bioreactor
. Reroute river
. Cover contaminated sediiimt in pi fine
. Collect and treat ccntaminated grcundwater
. Cn-site digrnmi of residue from timlina it of Northeast
Landfill soil
ALHER^UVE 3B . Remove and treat highly cu itdiiiinated sediment and soil
in en-site land treatment beds
. Reroute river
. Cover contaminated sediment in plane
. Cover remaining contaminated soil
. Collect and treat contaminated groundwater
. Cn-site disposal of residue from tmalntrit of Northeast
Landfill soil
AL3ERCOTVE 4
Rancve and toeat aaHfuiMiTt- having ccntaminant
1 x 10"6 targets using on-site
incineration
Replace and cover residue en-site with soil
-------
15
Alternative 1: No Action. A No Action Alternative was evaluated
in detail to serve as a baseline for comparison against remedial
action alternatives. It assumes that no corrective action will
be taken at the site and that no restrictions will be placed on
access or on future use of the site. There are no costs
associated with this alternative.
Alternative 2: Reroute River; Containment of Sediment and Soil;
Treatment of Groundwater; Off-site incineration of the Northeast
Landfill Area.
Time to Implement: 1-2 years
Capital Cost: $15,000,000.00
Annual O&M Cost: $ 130,000.OO
Total Present Worth Cost: $18,000,000.00
Under Alternative 2, a new river channel will be dug parallel to
the existing Little Menomonee River and the old river bed drained
and filled with soil from the new excavation. On-site soil will
be consolidated and covered with no treatment. Figure 8
illustrates the components of Alternative 2.
Rerouting River: Construction of the new river bed will proceed
from the railroad tracks just south of Brown Deer Road to the
confluence of the Little Menomonee River and the Menomonee River
downstream of the site. Sediment in the old channel will be
covered with soil from the new channel.
Because hazardous substances will be left in place, a soil
admixture will be mixed into highly contaminated sediment to
reduce the migration potential of the contaminants. An
appropriate admixture will be determined during design. A low-
permeability backfill will be placed in areas just upgradient of
intersections of the old and new river beds to reduce
preferential migration of contaminants to the new river.
The proposed river realignment, illustrated in Figure 7, will
require a detailed design study to assess the river hydraulics,
effects on the wetland and woodland environment, and the effects
on existing parkland and utilities. Consideration for
enhancement of environmental quality and aesthetics will be
addressed as well in the preliminary design phase. Construction
of the channel will comply with the guidance established by the
WDNR.
Soil: Contaminated on-site soil (about 210,000 cu/yds) will be
consolidated out of the flood plain and contained in place by
covering it with a 2-foot vegetated soil cover. This includes
soil in the 100-year floodplain exceeding the 1 x 10~6 target
concentrations. The permeable nature of the cover is intended to
enhance groundwater treatment by flushing out the contaminants
while preventing direct contact with the contaminated soil and
-------
LEGEND
TING nivpn ALIGNMENT
FIGUnE 7
PERMANENT RIVER RELOCATION
-------
Inrtultrv
Farm FI«M
APPROXIMATE
EXTENT OF
SOIL COVER
nn'lrlnntlftl Ap«rtm*n!t
CONTAMINATED SOIL
REMOVED AND TREATED OFFSETS
Rvtlrtancwt
LEGEND
^- - -' > V *. «r\j •" wr///\^
•s" ^ j \ H 4*\.*^m
****** , \J ^:'':'J ^^
• '-^^^^ /%** '
• "-• ^-^•-.o.; •"-.,.! ••-.
" ; • -S^.:-^;
"•TO
100 . VCAimOOO PLAIN
/SUMP, . . i y - ~
V: -~
APPHOXIMATF.
SCAI r IN Ff rt
FIGURE :
ALTERNATIVE 2 • CONTAINMENT OF
SOIL AND SFOIMFNT AND TRfiATMFNT
OF GfOUNOWATF.R
MO'-v*". »MFntc»n f.
-------
16
sediment.
Contaminated soil in the Northeast Landfill, about 1000 cu/yds,
will be removed and incinerated off-site at a licensed facility
to eliminate the need for long-term maintenance of property east
of the river.
Groundwater treatment; Contaminated groundwater from the west
side of the river will be collected by a series of supplemental
drains that lead into an interceptor drain running parallel to
the river, then flowing into a collection sump. The groundwater
treatment system is illustrated in Figure 9. A vertical
barrier, a synthetic geomembrane liner, will be placed along the
east wall of the main drain trench to prevent discharge of
contaminated materials to the river and recharge from the river
to the collection trench.
The treatment system will be designed to remove nonaqueous phase
liquids using an oil/water separator, and semivolatiles using
granular activated carbon or a comparable method demonstrated in
the predesign phase of remedial design. The treated water will
be discharged to the POTW or the river if the former is not
possible. The treatment system will be designed to achieve the
effluent limits established by the WDNR (see Table 2 below). .
Table 2
Water Quality-Based Effluent Limits for the Moss-American Site
Daily Monthly Annual
Maximum Average Limit Average Limit
Chemical (ppm) flb/dav) f Ib/vear)
Ethylbenzene
2,3,7,8-TCDD
Chloroform
Total CPAHs
45
—
29
—
200
1.9 X 10-9
1.6
1.9 X 10-3
—
6.9 X 10-7
—
0.68
The sewer is located on-site, just east of the river. Discharge
to the sewer, and consequently to the Jones Island POTW, requires
that the total VOC concentration be less than 5 mg/1. A Notice
of Intent to Discharge Industrial Wastewater must be filed with
the POTW.
Pure phase liquids collected will be hauled off-site for
treatment at a RCRA incinerator. The activated carbon will
periodically be removed and recharged off-site, and ultimately
disposed of at a RCRA facility. The time period over which
groundwater treatment will be required is difficult to predict
because of the heterogeneities in subsurface soil, the relatively
low mobility of the contaminants of concern (PAHs), and the low
hydraulic conductivities observed on-site. Since the source will
remain on-site, cleanup could take in excess of 200 years.
Groundwater cleanup standards: The cleanup standards for
-------
• MAIMOIUIN
• SUPPIFMENTM. OOAIN
• VERTICAL BARRIER
AQUIFER REMOVAL
~\ DISSOLVED CONTAMINANT PLUME
PURE PHASE PLUME
APPROXIMATE
SCALE IN FEET
Wnotlud V\ !
FIGURE 9
RECOMMENDED GROUNDWATER
REMEDIAL ACTION
uoss «Mrnir.AN FS
-------
Residential Ap*rtmnnt*
OBSERVED AREAL
EXTENT OF
CONTAMINATION
^ GROUNDWATER
COLLECTION TRENCH
/NEW RIVER CHANNFL
Form Fl.ld \ TREATED RESIDUALS
DISPOSAL ARI
GROUNOWATC
TREATMENT
EXISTING RIVER
CHANNEL BACKFILLED
TEMPORARY
STOCKPILING AREA
TREATED RESIDUALS
TEMPORARY STORAGE
APPROXIMATE
SCALE H FEET
RGURE10
ALTERNATIVE 3A - SLURRY TREATMENT OF
SOIL AND SEDIMENT AND TREATMENT
OF GROUNDWATER
UOSS-AMFRICAN FS
-------
17
groundwater are the preventive action limits (PALs) for the
following B-E-T-X compounds:
ES PAL
fug/1) fug/1)
Ethylbenzene 1360.0 272.0
Benzene 0.67 0.067
Toluene 343.0 68.6
Xylene 620.0 124.0
Groundwater quality will be evaluated in increments of 5 years
to determine if the remedial action objectives have been met.
If, after the ground-water operable unit has been operating for a
minimum of 5 years, it becomes apparent that it is not
technically or economically feasible to achieve the PAL, then a
Wisconsin alternative concentration limit (WACL) may be
established in compliance with the criteria in NR 140.28 of the
Wis. Adm. Code. The WACL that is established may not exceed the
enforcement standard (ES) for that compound. Refer to Section
10.2.3. Chemical Specific ARARs for a discussion of the point of
compliance. The groundwater cleanup standards are the same for
all alternatives.
Under Alternative 2 and the following alternatives, groundwater
monitoring will be conducted in the area of the contained soil.
Four wells will be sampled on a quarterly basis and eight others
will be sampled annually.
Alternative 3A: Reroute River; Partial Removal and Treatment of
Highly Contaminated Sediment and Soil by Bioslurry; Containment
of Remaining Sediment, Soil and Treatment Residue; Treatment of
Groundwater.
Time to Implement: 3-4 years
Capital Cost: $25,000,000
Annual O&M Cost: $ 130,000
Total Present Worth Cost: $26,000,000
Under Alternative 3A, the little Menomonee River will be
rerouted as described in Alternative 2, but the contaminated
sediment will be removed and treated on-site. The remaining
contaminated sediment will be covered in place with the soil
excavated from the new channel. The components of Alternative 3A
are illustrated in Figure 10.
Reroute of River; The new river channel will be constructed
parallel to the existing channel. Construction of the new river
bed will proceed from the railroad tracks just south of Brown
Deer Road to the confluence of the Little Menomonee River and the
Kenomonee River downstream of the site. The river will then be
diverted to the new channel. Following the diversion of the
river, the old channel will be drained and highly contaminated
-------
18
sediment removed by backhoe or end loader before backfilling the
old channel. Refer to Appendix B of the FS for a discussion of
possible construction techniques and approaches. The removal
equipment will load the sediment into a lined truck for hauling
to the site for treatment.
The proposed river realignment, illustrated in Figure 7, will
require a detailed design study to assess the river hydraulics,
effects on the wetland and woodland environment, and the effects
of existing parkland and utilities. Consideration for
enhancement of environmental quality and aesthetics will be
addressed as well in the preliminary design phase. Construction
of the channel will be undertaken in consultation with the WDNR
and the guidance established by the WDNR.
Soil and Sediment removal and treatment: Highly contaminated
soil (80,000 cu/yds) and river sediment (5,200 cu/yds) will be
removed and treated on-site using the slurry bio-reactor
technology. The removal criterion of "highly contaminated soil
or sediment" is defined as an extractable organic (EO) level of
1000 mg/kg or greater, or the presence of tarry or oily material
and/or a creosote odor. The removal of highly contaminated soil
and sediment is expected to remove all contaminated materials
that exceed a risk level of 1 x 10~4, which is defined as 6.1
mg/kg of CPAHs in soil, and 388 mg/kg of CPAHs in sediment. This
criterion was developed with the intent of removing the
contaminated material with the greatest migration potential and
thereby preventing further releases to the environment. The
removal criterion methodology will be further refined in the
design phase of the remedial action. The soil and sediment
removed will be treated to achieve the clean up level of 6.1
mg/kg of CPAHs, the target compound.
The bioslurry treatment, a two-part process, is illustrated in
Figure 11. The soil will be screened to remove oversized debris
and washed in an attrition scrubber. The washed soil that meets
clean up levels will be placed back on-site. Oversize material
will be treated according to Best Management Practices, i.e.,
triple wash or rinse, test/treat wash water in the groundwater
treatment system, and placed back on-site, if possible, in the
unit receiving the treatment residue. The volume of this
material is estimated at 500 - 3000 cu/yds. The remaining soil
will be "slurried", water is added to it to achieve optimum
moisture content, and pumped to the reactor tank along with the
sediment for treatment.
Slurry bioreactors treat contaminated soil by mixing the slurry
with microorganisms in an aerated reactor tank. The reactor
provides a favorable environment for microbial growth and
maintains contact between the contaminants and microorganisms
performing the degradation. As with other biological treatment
processes, temperature, pH, oxygen, and contact between
-------
Gl Or,'.V* FS
3?390
SURFACTANTS CW
AUOU.NEAGFNTS
( AS NECESSARY )
WASHED SANO
TOOtWATEniMG
OOOISFTE
DISPOSAL
DRY REMOVAL
OF SEDIMENT
CONTAMINATED SOIL
STOCKPILE
CONTAMINATED
GROUNDWATER
AIR
SLURRY BIOREACTOR
I
TREATED 'FINES'
FOR ONSITE
DISPOSAL
FIGURED
SLURRY BIOREACTOR
CONCEPTUAL PROCESS
FLOW SCHEMATIC
MOSS AMERICAN FS
-------
19
contaminants and microorganisms are critical factors controlling
the rate of degradation. Because these parameters can be more
easily controlled in an enclosed reactor than in a treatment bed,
slurry bioreactors achieve faster rates of degradation. Figure
11 is a conceptual process flow schematic for a slurry
bioreactor system.
Following degradation in treatment tanks, the slurry will be
piped to a thickener for separation. Solids will be further
dewatered before deposition back on-site, while the liquid phase
will be recycled. Wastewater generated from the dewatering step
will either be recycled for slurrying, or treated on-site prior
to discharge to the river. Activated carbon or filtration may
be employed before discharge if necessary.
The slurry will be discharged to a settling tank and dewatered.
Dewatered soil and sediment (treatment residue) meeting cleanup
levels will be covered on-site, along with the remaining soil,
with two feet of soil, six inches of topsoil, and revegetated as
in Alternative 2. Treatment residue not meeting cleanup levels
will be retreated.
Wastewaste generated from the dewatering step will either be
recycled for slurrying, or treated on-site in the groundwater
treatment system prior to discharge to the POTW or the river.'
Note; Because the contaminated soil and sediment contain a
listed hazardous waste, K001, treatment must comply with Land
Disposal Requirements (LDRs). Because existing and available
data do not demonstrate that the full-scale operation of this
treatment technology can attain the LDR treatment standards
consistently for all soil and debris wastes to be addressed by
this action, this alternative will comply with the LDRs through a
Treatability Variance for the wastes that cannot be treated to
meet the standard, as outlined in 40 CFR 268.44 and OSWER
Directive 9347.3-06FS: wastes will be treated until
concentrations of constituents restricted in the LDRs are below
the limits set by the Treatability Variance, and concentrations
of CPAHs are below health-based targets (1 x 10~4 excess lifetime
cancer risk) for soil (see the FS, Chapter 4 and Table 3 of this
document for specific treatment levels).
Bench-scale testing of a system similar to slurry biotreatment
was performed as part of the RI (see Appendix K of the
Feasibility Study) that indicated a 15-day retention time will
achieve the desired cleanup goal of 6.1 ppm CPAHs. Pilot tests
will be performed during preliminary design to more accurately
determine retention time to achieve cleanup goals. Since the
effectiveness of biological treatment methods is temperature
dependent, it is not expected that treatment will continue
during the winter; the design phase will also lo.ok at methods of
extending the months available for treatment. Other preliminary
-------
Table 3
TREATMENT LEVELS TO BE OBTAINED
TO COMPLY WITH LDR TREATBILITY VARIANCE
Conlamlnanl
LDR CONSTITUENTS FOR K001
Pontachlorophonol
Napihatono
Phonanthrone
Pyrone
Toluene
Xylene
Lead
CONTAMINANTS OF CONCERN
2.4-dlnltrophenol
Cadmium
Chrysene
Benzo(a)anihracene
Benzo(a)pyrene
Benzo(b)Muoranihene
Benzo(H)liuoranlhene
Benzo(ghi)perlyene
Oibenz(ah)anthracene
idono( 1 23cd)pyf one
Reference
Concontrallon
(mo/Kg)
2250
30000
--
225
22500
150000
--
37.5
NA
•
•
•
•
•
•
*
1x10-4 Excess
Llfollmo Cancor
Risk Targol
(mg/Kg)
NA
*
*
•
•
•
•
6.
6.
6.
6.
6
6.
6.
6.1
Observed
Conconirallon
Range (mg/Kg)
RDL
0 019 - 2GOO
0 06 - 4600
0.016- 2000
0.002 - 2.0
0.002- 17
2.3- 519 (TWA)
620
1.6-76
0.038-510
0.069 - 420
0 040 - 230
0 010 - 270
0014- 250
0 044 - 77
0.051 - 24
0.029 - 78
Threshold
Concentration
(mo/Kg)
400 (TWA)
400 (TWA)
400 (TWA)
400 (TWA)
100 (TWA)
100 (TWA)
300 (TCLP)
NA
•
•
•
*
»
•
•
•
•
Concentration
Range
To Be Achieved
(mg/Kg)
95 percent reduction
Of 20 mo/Kg (TWA)
•
•
90 precent reduction
or 10 mg/Kg
3 mg/Kg (TCLP)
NA
NA
90 percent reduction
or sum ol carcinogenic
PAHS< 61 mo/Kg
•
•
•
•
•
Sum ol carcinogenic PAHs 6.1 <0.33 - 1900
NOTES
i Concentration ranges defined In "Superlund LDR Guidance. #6A"; OWSER 9347.3-06FS.
2. Only the concentration range lor LDR constituents lor K001 need lo be attained to comply with LDRs.
3 Contaminants ol concern include only the primary contaminants ol concern icloniidod in the basoime risk assessment
4. Observed concentration range lor soil and sediment.
5 No threshold concentrations developed lor toluene and xylene. Ranges basod on • Oihor Polar Oiqanics' category
6 Tmatabihly Variance applies to Alternatives 3A, 3B. 4, and 5.
-------
20
design tasks include:
* A sampling survey to better define the volume of
contaminated soil and sediment to be managed;
* Additional flood plain sampling to verify extent of
contamination;
* Further characterization of groundwater conditions and
contamination potential on east side of the river;
* Establishment of dewatering design to lower groundwater
for soil removal;
* Further investigate the possible extent of soil and
groundwater contamination in the pit and ditch area;
* Incorporation of results of the seasonal fluctuation
in groundwater elevation study already in progress;
* Refining of verification methods for determining
contamination levels in the field;
* Establishment of background PAH concentrations that
are more in keeping with the SQC values for areas where
the old and new channels tie in to pass under bridges.
* Environmental design studies described under Flood
Plain and Wetland ARARs in Section 10.2.2.
Groundwater Collection and Treatment; Groundwater treatment and
cleanup standards are the same as Alternative 2, but, because
much of the source of groundwater contamination will be removed
for treatment, supplemental drain systems may not be necessary
and the treatment time will be shortened to less than ten years.
In addition, some of the groundwater treatment can be
incorporated into the slurry treatment when the system is in use,
i.e., the collected groundwater can be used to slurry the soil.
As in Alternative 2, the groundwater cleanup standard is the PAL
for the B-E-T-X compounds:
ES PAL
(ug/1) rua/1)
Ethylbenzene 1360.0 272.0
Benzene 0.67 0.067
Toluene 343.0 68.6
Xylene 620.0 124.0
Groundwater quality will be evaluated in increments of 5 years
to determine if the remedial action objectives have been met.
If, after the ground-water operable unit has been operating for a
minimum of 5 years, it becomes apparent that it is not
-------
21
technically or economically feasible to achieve the PAL, then a
WACL may be established. The WACL that is established may not
exceed the ES for that compound.
As described under Alternative 2, groundwater monitoring will be
conducted in the area of the contained soil. Four wells will be
sampled on a quarterly basis and eight others will be sampled
annually.
Northeast Landfill treatment; Contaminated soil in the Northeast
Landfill/ about 1000 cu/yds, will be removed, treated on-site in
the slurry biotreatment unit, and the residue disposed of on-site
within the AOC along with the other treatment residue and
consolidated soil as described in the following paragraph. The
FS evaluated off-site disposal for this alternative. On-site
disposal will accommodate Wisconsin's Hazardous Waste Capacity
commitment and will also provide a disposal unit for debris that
will otherwise require disposal off-site.
Cover: Treatment residue generated from the slurry bioreactor,
and on-site contaminated soil exceeding the 1 x 10~° target
concentrations, a total of about 210,000 cu/yds, will be
contained within the AOC, covered with 2 feet of clean soil and 6
inches of topsoil. The cover will be vegetated to reduce
erosion and improve aesthetics. To further reduce the likelihood
for exposure to the contained soil and residue, deed restrictions
will be placed on the site to prevent its development and the
area of contained soil will be fenced. U.S. EPA has determined
that, while a RCRA-type closure is applicable to waste within the
AOC, because placement has occurred, it is not technically
suitable.
The nature of the waste, its distribution, and the principal
routes of exposure indicate that an impermeable cap, liner, and
leachate collection system would decrease the efficiency of the
groundwater treatment system, prolonging the treatment time and
providing no benefit over the proposed hybrid soil cover -
Proposed NCP page 51446. A hybrid soil cover is considered
equally as effective in limiting soil ingestion, but would permit
natural flushing to the groundwater collection and treatment
system, and encourage biodegradation of hazardous substances in
the vadose zone. If natural flushing does not occur, groundwater
collection and treatment could take in excess of two hundred
years during which time hazardous waste would remain on-site,
posing considerable risk to human health and the environment.
For this reason, pursuant to CERCLA section 121(d), the Greater
Risk to Health and the Environment waiver will be invoked to meet
State RCRA closure requirement for an impermeable cap, liner, and
leachate collection system.
-------
22
Alternative 3B: This alternative is the same as Alternative 3A
except that it uses a biological land treatment system rather
than a slurry bioreactor to treat contaminated soil and
sediment.
Time to Implement: 8-15 years
Capital Cost: $22,000,000
Annual O&M Cost: $ 500,000
Total Present Worth Cost: $26,000,000
Under Alternative 3B, the Little Menomonee River will be
rerouted as described in Alternative 3A. Highly contaminated
soil and sediment will be removed and placed on land treatment
beds to biologically degrade the contaminants of concern: an
estimated 80,000 cu/yds of soil and 5,200 cu/yds of sediment
will be removed and treated over the course of 8 to 15 years.
Figure 12 illustrates the components of Alternative 3B. All
components other than the land treatment beds are the same as
described in Alternative 3A.
Removal and treatment of soil and sediment; The 10 acre
treatment beds will be located west of the river, over the old
storage and disposal areas as illustrated in Figure 12. At a
soil application thickness of 1 foot, it will be possible to
treat about 16,000 cu/yds of soil at a time. Because soil there
is already contaminated, a temporary soil stockpiling area will
be constructed to accommodate the material while the treatment
beds are being constructed. The stockpiling area will be
designed to contain and collect leachate from the pile.
Before stockpiling, soil will be screened to remove oversized
debris. The oversized debris will be treated as in Alternative
3A except for wood chips which will be managed along with the
contaminated soil in the treatment beds.
The land treatment system is depicted in Figure 13. The
treatment beds will consist of a layer of clay overlain by a
synthetic liner in turn overlain by a sand layer, a primary
synthetic liner, and another sand layer. The beds will contain
drains for collecting leachate generated during treatment. A 1-
foot layer of contaminated soil and dewatered sediment placed on
the beds will be periodically tilled to maintain aerobic
conditions in the soil. Sewage sludge, manure, or another
suitable material could be tilled into the soil to provide
nutrients for the micro-organisms. Leachate collected from the
treatment beds will be conveyed to a holding tank where it will
either be recycled to the groundwater treatment unit or
discharged to the sanitary sewer.
Average soil CPAH concentrations are estimated to be 500 to 600
mg/kg and average sediment CPAH concentrations 200 to 400 rog/kg.
Results of a treatability test (see Appendix K) indicate that 6
-------
-
, OBSERVED AREAL
r- I CVT«-»IT f\r
^ GROUNOWATER
• S COLLECTION TRENCH
CM i rn i \jt-
CONTAMINATION
NEW RIVER CMANNEI
EXISTING RIVER
CHANNEL BACKFILLf O
GROUNOWATCR,
TREATMENT
LtCENO
. SlTf BOUNOAP
CONSTRUCTION
SUPPORT
AREA
100 rfAH fiooo PLAIN
STOCKPILING
AND STAGING
AREA
TREATED
RESIDUALS
STORAGE
APPROXIMATE
SCALt IN FEET
FIGURE 1 2
ALTERNATIVE 3B - LAND TREATMENT OF
SOIL AND SEDIMENT AND TREATMENT
OF GROUNOWATER
un-v;-*uf nif»N i •.
-------
PERFORATED PIPE
FOR LEACHATE
COLLECTION'
1' TO 1-1/2'
LAYER OF
CONTAMINATED
SOIL
2' SAND
GEOTEXTILE
GEONET
SYNTHETIC LINER
GEOTEXTILE
V SAND (LEAK
DETECTION)
GEOTEXTLE
SYNTHETIC LINEP
COMPACTED
SECONDARY
SOIL LINER
c
r,
V.
§
L>
I'.
u.
s
FIGURE 13
CONCEPTUAL CROSS SECTION
OF LAND TREATMENT BED
MOSS-AM£RlCA\ 'S
-------
23
to 12 months of treatment will be required to achieve cleanup
levels. Actual residual PAH concentrations and the length of
time it will take to achieve them will be determined by pilot
studies during the remedial design phase. Cold temperatures
will limit the treatment season to May through September.
Treated soil and sediment will be placed in a lined storage bed
west of the river until all contaminated soil and sediment could
be treated. This alternative will comply with LDR treatment
requirements through a Treatability Variance as in Alternative
3A. Once all of the soil and sediment, including that from the
Northeast Landfill area, has been treated, the stockpiled
(treated) soil and sediment will be placed back on the treatment
beds, covered with soil, and planted with vegetation. Leachate
from the treatment beds will continue to be collected, treated,
and monitored.
Groundwater Collection and Treatment; Groundwater will be
collected and treated as in Alternative 3A. Management of
residuals is the same except that oil sludge and skimming could
be treated in the on-site treatment beds.
Alternative 4: Removal and Treatment of Sediment only;
Containment of soil; Groundwater Treatment, does not Reroute-
River.
Time to Implement: 1-2 years
Capital Cost: $17,000,000
Annual O&M Cost: $ 130,000
Total Present Worth Cost: $20,000,000
Under Alternative 4, 33,000 cu/yds of contaminated sediment with
concentrations of contaminants exceeding background CPAH levels
(currently estimated at 18 ppm) will be removed and treated by
slurry bioreactor. Residue from the slurry bioreactors will be
consolidated with contaminated on-site soil and covered. Unlike
Alternatives 3A and 3B, which also excavate and treat sediment,
the Little Menomonee River will not be rechanneled. As with
Alternative 3A, contaminated soil in the Northeast Landfill area
will be treated on-site and the residue disposed of on-site in a
RCRA compliant unit.
Sediment removal and treatment; Removal and treatment of the
sediment uses the same methods as Alternatives 3A and 3B, but,
since no new channel is being constructed, the river will
temporarily bypass segments to be excavated. This will be
achieved by damming the upstream end and bypassing or pumping
water around the area of excavation during the removal (see
Appendix B of the Feasibility Study). The difference between
Alternative 4 and Alternatives 3A and 3B is .that a greater amount
of sediment will be removed because the existing river alignment
will remain the same. Some reconstruction and modifications to
-------
24
the channel will be necessary to provide stable banks and to
mitigate impacts on wetlands. Appendix B of the FS describes the
requirements of channel reconstruction.
Removal of sediment exceeding background CPAH levels will reduce
acute exposure risks to humans to 1 x 10~5 and significantly
reduce both acute and chronic risks to aquatic life. The level
of 18 ppm CPAHs may not be sufficiently protective for aquatic
life. Wisconsin Sediment Quality Criteria, a To Be Considered
(TBC), indicates that 3 ppm, which equates more closely to the 1
x 10~° risk level for sediment, is required. Because of the
irregular distribution of contaminants and physical limitations
of the removal equipment, the actual difference in sediment
volume removed, 18 ppm versus 3 ppm, may not be significant.
More of a problem is that this concentration approaches detection
limits and more exact field verification methods will be
required. This verification will require more sensitive mobile
laboratory detection methods, and that a greater number of
samples be taken to determine if sediment removal was sufficient
to meet criteria.
As in Alternative 3A, Alternative 4 will comply with LDR
treatment requirements through a Treatability Variance and
sediment will be treated until the residue have concentrations
less than the health-based limits (1 x 10~4 excess lifetime
cancer risk) for soil or 6.1 ppm CPAHs.
Soil; All contaminated soil in the AOC, will be consolidated
and contained in place beneath a soil cover. As with Alternative
3A, contaminated soil in the Northeast Landfill area will be
treated on-site and treatment residue disposed of on-site along
with the treatment residue from the sediment.
Groundwater Collection and Treatment; Contaminated groundwater
will be collected and treated as under Alternative 2. Since the
source is still on-site, groundwater collection and treatment
could take more than 100 years.
Alternative 5: Removal and Treatment of Soil and Sediment;
Groundwater Treatment.
Time to Implement: 4-6 years
Capital Cost: $23,000,000
Annual O&M Cost: $ 130,000
Total Present Worth Cost: $24,000,000
Alternative 5 combines components of Alternative 3A and
Alternative 4. The treatment method, target concentration of
treatment residue, and disposal of residue for sediment and soil
is exactly the same as Alternative 3A; also the same is
groundwater treatment, and treatment and disposal of the
Northeast Landfill contents. As in Alternative 4, the river is
-------
25
not rerouted and sediment having concentrations of contaminants
exceeding background CPAH levels are removed and treated.
Sediment Removal and Treatment; The river sediment removal
method, the volume removed, and the treatment is the same as
Alternative 4 and will also comply with LDR treatment
requirements through a Treatability Variance, treating to less
than 6.1 ppro CPAHs.
On-site Soil; The volume of soil, removal and treatment is the
same as Alternative 3A and will also comply with LDR treatment
requirements through a Treatability Variance, treating to less
than 6.1 ppm CPAHs.
Groundwater Collection and Treatment; The groundwater treatment
system and management of residuals is as described for
Alternative 3A. The groundwater treatment period is estimated to
be less than 10 years.
Alternative 6: Incineration of Soil and Sediment.
Time to Implement: 4-5 years
Capital Cost: $89,000,000
Annual C&M Cost: $ 18,000
Total Present Worth Cost: $89,300,000
Alternative 6, proposes to excavate and incinerate all soil
exceeding the 1 x 10~6 risk target concentrations and sediment
exceeding background CPAH levels (currently estimated at 18 ppm)
on-site using mobile incinerators. The river will not be
rerouted. Soil and sediment will be treated to 1 x 10~6, or .06
ppm CPAH. This treatment level will meet LDRs, a Treatability
Variance will not be required. Treated soil and sediment will be
replaced on-site, covered, and delisted. Groundwater collection
and treatment will probably not be required following the removal
of source material. Figure 14 illustrates the components of
Alternative 6.
Sediment Removal; The river will be temporarily rerouted
segment by segment and contaminated sediment removed as in
Alternatives 4 and 5. To decrease the cost of incineration and
to increase the processing rate, the sediment will be dewatered
before incineration. An estimated 33,000 cubic yards of sediment
will be incinerated.
On-site Soil; Soil above the water table with contaminant levels
exceeding the 1 x 10~"6 target risk range, and soil below the
water table with CPAH concentrations greater than 10 mg/kg, about
130,000 cu/yds, will also be excavated and incinerated. This
will include contaminated soil in the Northeast Landfill area.
It is estimated that the maximum depth of excavation will be
about 20 feet.
-------
--
\\". \ \y: - :\~-----.-.--:• I ^-^^^3^- \^r^^/^yr^^^r
THEATtO RESIDUALS
TEMPOHARY STORAGE
»prnoxiM«TE
SCALE IN FEET
\
FIGURE 1 '
ALTERNATIVE 6 • INCINERATION OF
SOIL AND SEDIMENT AND TREATMEU
OF GROUNDWATER
-------
26
Treatment by Incineration of Sediment and On-site Soil; Based
on the large volume of contaminated soil and sediment (about
160,000 cu/yds, two on-site incinerators will be required.
Operation will continue throughout the year. Because the
proposed location for the treatment facility is over contaminated
soil, the first phase of the project will require temporary
relocation (stockpiling) of the soil underneath the area of the
treatment system. As in Alternatives 3B, the stockpile area
will be designed to collect any leachate or runoff from the area,
and to direct the leachate to a treatment system. A conceptual
layout and more specific information about this alternative can
be found in Chapter 3 of the FS. Approximately 100,000 cu/yds
of treated soil (ash) will be generated from the incineration.
Management of Residuals; Treated soil and sediment will be
replaced in the former storage area. Since the concentrations in
soil and sediment will be reduced to below the 1 x 10~6 target
level, long-term management of these residue will not be
required for the protection of human health. The area of
disposal will be covered with soil and planted with vegetation.
Residue generated from the treatment of materials removed from
the Northeast Landfill area will also be disposed of on-site,
since all residuals generated from thermal treatment are expected
to be delisted. Oversized material that could not be incinerated
on-site will be disposed of off-site in a RCRA-compliant
landfill.
Groundwater Collection and Treatment; Since soil at depths of 5
to 10 feet below the water table will be removed, it is
anticipated that groundwater collection and treatment will not be
required beyond the period of remedial action construction.
Groundwater treatment is the same as that described for
Alternative 3A.
8. Summary of Comparative Analysis of Alternatives
The alternatives are evaluated against the nine criteria
contained in the NCP (40 CFR 300.430)(e)(9)(iii), by balancing
long-term effectiveness and permanence, reduction of toxicity,
mobility, or volume through treatment, short term effectiveness
and implementability with the cost of the remedy. This
evaluation determines the most protective and cost-effective
alternative that will meet the objectives of the Feasibility
study at the Moss-American Site. The nine criteria are as
follows:
1) Overall Protection of Human Health and the Environment.
U.S. EPA measures each alternative by how effectively risks
posed by each exposure pathway are eliminated, reduced, or
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27
controlled through treatment, engineering controls, or
institutional controls.
2) Compliance with Applicable or Relevant and Appropriate
Regulations (ARARs).
The alternatives are evaluated for compliance with State and
Federal ARARs determined to be applicable, or relevant and
appropriate to the site or provide grounds for invoking a
waiver.
3) Long-Term Effectiveness and Permanence.
This criterion relates to the degree of residual risk and
the ability of a remedy to maintain reliable protection of
human health and the environment over time, once cleanup
goals have been met.
4) Reduction of Toxicity. Mobility, or Volume through
Treatment.
This criterion relates to the anticipated performance of the
treatment technologies a remedy may employ.
5) Short-Term Effectiveness.
This criterion addresses the period of time needed to
achieve protection against any adverse impacts on human
health and the environment that may be posed during the
remedy's construction and implementation period, until
clean-up goals are achieved.
6) Implementability.
This criterion addresses the technical and administrative
feasibility of a remedy, including the availability of
materials and services needed to implement a particular
option.
7} Cost.
This criterion includes estimated capital costs, operation
and maintenance costs, and present net worth costs.
8) State Acceptance.
This criterion addresses the State's comments.
9) Community Acceptance.
This criterion summarizes the public's general response to
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28
the alternatives described in the proposed plan and RI/FS
report.
1) Overall Protectiveness of Human Health and the Environment
With the exception of the No-Action alternative (Alternative 1),
each of the alternatives is protective of human health and the
environment and will reduce site-related risks to health based
levels and an acceptable risk range of 1 x 10~4 to 1 x 10~6.
The technologies employed for treatment alternatives are
considered reliable, and will be pilot or field tested to refine
their effectiveness. Alternatives 3A, 3B, 5 and 6 reduce all
site risk levels to less than 1 x 10~^ through treatment.
Alternative 2 and 4 do not provide as much overall protectiveness
because soil contamination will be covered but not reduced in
toxicity.
All alternatives will be protective of aquatic habitat and the
river corridor by either removing the contaminated sediment or
providing a clean channel for the river. There is, however, a
greater likelihood that the re-routing alternatives (2, 3A, and
3B) will provide better protection of the aquatic habitat
because, in addition to providing a clean channel that meets '
Wisconsin's SQC, shown in Table 4, the new channel could be
constructed in a way that more closely resembles the historical
stream characteristics, i.e. prior to dredging.
Alternative 2, while adequate, is considered the least reliable
since all the contaminant mass is contained in place.
Contaminants in sediment could migrate back to the new river, and
contaminants in contained soil could be exposed in the future if
deed restrictions are not in effect.
2) Compliance with ARARs
All alternatives except the No-Action Alternative will comply
with ARARs. Alternatives 4, 5, and 6 do not meet Wisconsin's
SQC, which though not ARARs, are TBC. Section 10, the Statutory
Determinations section- discusses ARARs for the Alternative 3A,
the preferred alternative.at the Site.
3) Lonq-Term Effectiveness
All alternatives except the no action alternative will reduce
residual risk to within the acceptable risk range of 1 x 10~4 to
1 x 10~6 through treatment or containment. Alternative 6 reduces
residual risk to less than 1 x 10~6 for all treated media.
Incineration of contaminants and delisting of the ash will
achieve clean closure; no institutional controls or other long
term maintenance will be required at the Site.
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10
12 .
1 3 .
11 .
15.
1 f. .
1 'I
Table t,
Sediment Quality Criteria (SQC) For Little Menomonee River
Based on a Range and Mean Total Organic Content Found in Bottom Sedimento
Moos-American Site
SOC Derived From Water Quality Standards Contained
In Tables 8 and 9, NR 105, and NR 102, Win. Adm. Code
Compound
Polynuclear Aromatic
Hydrocarbons (PAHe)
Fluoranthene
Ethylbenzene
Chloroform
Methylene Chloride
Dl-n-butylphthalate
2,3,7.8-Tetrachloro-
dlbenzo-p-dloxin
Benzo(a)pyrene
Acenaphthene
Naphthalene*
Toluene
Acenaphthene
Phenanthrene
Pyrene
R e n 7. o (a )Anthracene
F1 noranihone
II on 7. o < a ) Py rone
SOC In
Percent Organic
1%
890
12, 160
110,000
27.0
1,260
1.1 x 108
0.0033
890
920
2\
1,700
24, 320
220,000
53.9
2,520
2.2 x 108
0.0066
1,780
1,840
3\
2,670
36,480
330.000
80.9
3,780
3.3 x 10°
0.0099
2,670
2,760
ug/kg Baned on
Carbon In Sediment, (foe)
.Average
3 . 22*
2, 866
39, 155
354, 200
86.8
4,057
3. 6 x 108
0 .0106
2,866
2,962
4\
3,560
48,640
440.000
107 .9
5,040
4.4 x 108
0.0132
3,560
3.680
5\
4,450
60,800
550,000
134.9
6, 300
5.5 x 108
0.0165
4,450
4, 600
6\
5, 340
72.960
660,000
161.9
7, 560
6.6 x 10*
0.0198
5, 340
5,520
SOC Derived From "Quality Criteria For Water 1986", U.S. EPA
12,400
52,500
24,800
105,000
37.200
157,500
39,928
169, 050
49.600
210.000
62.000
262.500
74 , 400
315,000
SOC Daoed on U.S. EPA (1988) Interim SOC
SOC In
Percent Organic
2,
13,
13,
18,
10,
1%
622
896
110
170
030
630
5,
1,
26,
26,
37,
21 .
2%
244
792
220
340
660
260
7,
2,
39,
39,
56 ,
1 1 ,
3%
866
688
.330
510
•ion
(I'M)
ug/kg Based on
Carbon In Sediment (Poc)
3 . 22%
8,
2,
42,
4 2 ,
Ml ,
1-1 .
442
855
214
407
632
7 ,>r>
10,
3,
52,
52,
75 ,
4 ') .
4\
488
584
440
6BO
120
S20
Average
13,
4,
65,
65,
94 .
53 .
110
480
550
850
150
1 50
15,
5,
78,
79 ,
112,
6.1,
732
37 6
660
020
180
780
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29
Alternatives 2, 3A, 3B, 4 and 5 will all reduce residual risks
at the Site to 1 x 10~4 or less. Alternatives 3A, 3B, and 5
will be more effective in the long term than alternatives 2 and
4, as they treat the highly contaminated soil and sediment,
leaving a treatment residue to be contained on-site that does not
exceed health based levels. The risk from contained sediment is
that the contaminants could migrate to the new channel. The
migration potential is thought to be negligible, but will be
addressed in the design phase of the remedial action. If the
potential exists, a cohesive substance will be added to the
remaining sediment to stabilize it; monitoring wells will be
placed between the old and the new channel. Removal of highly
contaminated sediment before re-routing the river, as in
alternatives 3A and 3B, including any with free product, will
reduce this potential greatly.
Failure of the soil cover in the AOC is not likely to cause
increased risks to public health and the environment because 1)
no contamination will be present above the 1 x 10~4 risk level,
2) contaminant migration to groundwater will be contained by the
groundwater collection system, and 3) portions of the Site where
soil will be covered will be fenced off. Alternative 4 does not
provide as much long-term effectiveness as the other
alternatives because none of the soil is treated except the
Northeast Landfill area. It will rely on deed restrictions and
fencing to prevent contact with contaminated soil.
Alternative 2, while it reduces all risks on the Site to health
based levels, has the greatest long-term residual risk as no
treatment is performed and it relies upon containment, fencing
and deed restrictions for long-term effectiveness. The potential
for contaminant movement from buried sediment will be retarded
by an admixture mixed with sediment in the old channel and
monitored by monitoring wells placed between the old and the new
channels.
4) Reduction of Toxicitv. Mobility, or Volume through Treatment
Alternative 6 achieves a slightly greater level of reduction in
toxicity and could achieve the lowest levels of residual
contamination. Incineration is designated as the Best Available
Technology (BAT) for PAHs; it is anticipated that more than 99.99
percent of the contaminant mass in the treated material will be
destroyed by incineration. Volume will not be significantly
reduced as about 75,000 cu/yds of incinerator ash will be
produced.
All the treatment alternatives will achieve significant
reductions in toxicity. Alternatives 3A, 3B, and 5 will achieve
greater reductions than Alternative 4, which does not treat the
on-site soil. Alternative 3A and 3B treat less material than
Alternative 5 and 6, but treat the more heavily-contaminated
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30
sediment and soil and therefore treat a significant fraction of
the contaminant mass. All soil and sediment treated in the
slurry bioreactor and in the land treatment facility will be
treated until residual risk levels are reduced to the cleanup
level for CPAHs of 6.1 ppm or below the 1 x 10~4 risk level.
Alternative 2 will result in the least reduction in toxicity as
only the small Northeast Landfill area will be treated through
off-site incineration.
Groundwater treatment proposed under Alternatives 2 through 5
will reduce contaminant toxicity of contaminants in groundwater.
It will reduce the target B-E-T-X compounds to the clean up
standards discussed in Section 7, through removal of toxic
organic compounds from groundwater by adsorption, and the
destruction of these contaminants during subsequent thermal
treatment of the carbon used for adsorption in the regeneration
phase. Free product from the oil/water separator will also be
destroyed by off-site incineration. Treatment time for
Alternatives 2 and 4 will be extremely prolonged as the source
will not be removed.
5) Short-Term Effectiveness
Short Term Risks to the Community: Because all the alternatives
(except the No Action) involve handling contaminated sediment
and/or soil, a temporary increase in risk to the community
because of the potential for inhalation of windblown soil, or
direct contact with contaminated sediment transported off-site is
common to all. Alternative 2 involves less hazard from
excavation and handling, as it does not provide for removal of
contaminated sediment. The increased risk from contaminated
dust could be mitigated through the use of dust suppressants,
limiting earthmoving and grading activities on windy days, and
downwind monitoring during construction activities. The use of
the old channel as a temporary road will also limit truck
traffic on city streets.
Alternatives 3A, 4 and 5 may have an organoleptic factor (odor)
associated with them, but Alternatives 3B and 6 are expected to
be the greatest nuisance, since land treatment (Alternative 3B)
could result in odors downwind of the Site, and the incinerator
(Alternative 6) could result in a steam plume, potential odors
and a temporary decrease in air quality in the community.
Short Term Risks to Workers: Because worker exposure from direct
contact and dust inhalation is a function of the amount of
contaminated sediment and soil removed, potential for worker
exposure during excavation will be high for Alternatives 3A
through 6 but could be the greatest for Alternative 3B, since
workers will till the contaminated soil periodically for several
years. Standard protection methods, such as adequate safety
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31
clothing and equipment will be employed to ensure no
unacceptable short term risks occur.
Short Term Risks to the Environment: Short-term environmental
impacts to the river and the river corridor will be significant
for all alternatives involving action at the Site, since all
will impact portions of existing aquatic habitats. Alternative
2, 3A, and 3B could have more adverse impact than Alternatives 4,
5, and 6 because the entire 5-mile length of stream habitat and
river corridor will be involved in the construction.
Restoration of these habitats is anticipated to take longer for
alternatives that reroute the river than for alternatives that
use the current channel. Adverse impacts on aquatic life will
be limited to the Little Menoroonee River by controlling
resuspension of sediment and erosion to prevent migration of
contaminants into the Menomonee River. It is anticipated that
long-term benefits will outweigh short-term adverse effects by
significantly increasing both the quality of the aquatic habitat
and the recreational opportunities available in the river
corridor.
An ecological assessment, including aerial photographs, is
currently being performed at the Site. This assessment will be
used in the design phase to develop a plan that will limit
impacts to wetlands as much as possible by designating areas of
least impact, suitable areas for wetland mitigation and
replacement, and determining the quality of existing wetlands.
If it is determined that critical habitats or endangered species
exist in specified areas, then appropriate action will be taken
to avoid impact to these areas, such as limiting activity on the
river to dredging, and/or limited removal of sediment. This plan
will be implemented in the remedial action under Alternatives 2
through 6.
The ecological assessment will also include a survey of fish
communities downstream from the Site that can act as a measure of
remedial action success.
Time until Protection is Achieved: The time required to achieve
remedial action goals for soil and sediment is not significantly
different between alternatives except for Alternative 3B.
Alternative 2 will require the shortest time, 1 to 2 years of
remedial action construction, because pilot testing is not
required and construction techniques are straightforward.
Because preliminary design and design activities for
Alternatives 3A and 4 will require 1 or 2 additional years,
attainment of remedial action goals will require 3 or 4 years.
Alternatives 3B, 5, and 6 will take the longest to achieve
remedial action goals - 5 years for Alternatives 5 and 6, and 15
years for Alternative 3B.
Groundwater standards will probably be achieved during the
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32
construction period for Alternative 6. Alternatives 3A, 3B, and
5 could achieve groundwater standards within 5 to 10 years.
Protection of the river from contaminated groundwater, however,
could be achieved in the first several years of the construction
period for all alternatives except Alternatives 1, 2 and 4.
Since there is no source removal for Alternatives 2 and 4, time
to achieve the groundwater remedial action standards could be in
excess of 200 years.
In summary, none of the alternatives provides significantly
better short-term effectiveness than other alternatives. Each
will have similar adverse short-term environmental impact, and
require several years to achieve remedial action goals for soil,
sediment and groundwater.
6) Implementability
Implementation will be difficult for all alternatives. The most
difficult implementation aspect relates to work on the river,
which is included in all alternatives except no action.
Construction work on the river involves excavating a new channel,
trucking contaminated sediment to the treatment site (for
Alternatives 3A through 6), and restoring the wetlands and
surrounding areas. Work in the river area will require careful
design and planning as well as coordination with numerous
agencies, including Milwaukee County, the Milwaukee Metropolitan
Sewerage District, the City of Milwaukee, and the WDNR. This
difficulty exists for all alternatives except the No Action
Alternative, and to a lesser extent for Alternative 2 since no
sediment will be removed.
Those alternatives that remove sediment to the health-based risk
level of 1 x 10~4 or 388 ppm CPAHs, Alternatives 3A and 3B, will
be easier to implement in the field than alternatives that clean
up to background or lower, such as Alternatives 4, 5, and 6.
While it is possible in theory to develop field detection
methods that will allow removal of sediment contamination to
lower levels, these levels require sample testing at detection
limit levels or lower. Field detection methods become by
necessity more delicate and difficult once there are no physical
indicators of contamination such as color, sheen or smell. If
there is a physical indication of contamination, its presence can
be verified by mobile laboratory methods. If there are no
physical indicators, laboratory verification of contamination
will require that a greater number of samples be taken and sent
off-site for testing. Delays could occur while the contractor
waits for laboratory verification of contamination levels in
order to delineate removal boundaries. This could also result in
the removal of much larger volumes of sediment than anticipated,
not because the sediment is contaminated but because it is too
difficult to prove that it is not contaminated. •
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33
Technology Status: All alternatives use demonstrated
technologies that are readily available. While treatment of
sediment contaminated with PAHs in a slurry bioreactor is
considered an innovative technology, the basic components of the
technology are proven and have been used frequently enough to be
easily designed and implemented. Biodegradation of PAHs has
been practiced for years in land treatment of petroleum
hydrocarbons. Slurry reactors have also been used extensively in
various applications. The use of a slurry bioreactor to treat
sediment is similar to the use of aerobic or anaerobic digester
to treat municipal and industrial waste water. Mining process
applications of slurry reactors have established appropriate
procedures for the materials feeding, slurry mixing, and solid
dewatering components required in a slurry bioreactor
application. Slurry bioreactors have been successfully used to
treat solids contaminated with PAHs at other sites; bench scale
tests conducted in the Treatability Study indicate that the
technology will be effective at the Moss-American Site.
7) Estimated Cost
The estimated costs for remedial actions, listed in Table 5, are
order-of-magnitude estimates with an intended accuracy range of
+50 percent and -30 percent for the identified alternative. .The
estimated cost of the selected remedial action will be further
refined in the final design. Capital costs are the direct and
indirect costs required to initiate and install a remedial
action. Annual operation and Maintenance cost (O&M) include the
annual operating cost for a remedial action incurred and paid on
a yearly basis following implementation of the remedial action.
Present worth analysis (PW) provides a method for evaluating and
comparing costs that occur over different time periods by
discounting future expenditures to the present year.
The No-Action Alternative has no cost but will provide no
protection of human health and the environment. Alternative 2
has the least capital cost of the alternatives that propose
remedial action, and is protective of human health and the
environment as long as the cover remains intact and there is no
disturbance of the covered channel. This alternative, however,
is estimated to incur the highest operation and maintenance costs
due to the lengthy groundwater treatment time. Long-term
management will be significantly reduced or eliminated under
Alternatives 3A and 3B for a moderate increase in capital cost.
Alternatives 4 and 5 are estimated to have costs similar to
Alternatives 3A and 3B but will not provide as much protection
to human health and the environment. Alternative 4 will, like
Alternative 2 require lengthy groundwater treatment.
Alternative 6 provides marginal improvement in protection of
human health and the environment at significantly greater cost.
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34
Table 5
Estimated Cost of Remedial Action
Moss-American Site
Alternative
1
2
3A
3B
4
5
6
Note: O&M =
PW =
Capital Cost Annual O&M
$ o
15,000,000
25,000,000
22,000,000
17,000,000
23,000,000
89,000,000
= Operation and
Present Worth
130,000
130,000
500,000
130,000
130,000
18,000
Maintenance
Total PW
18,000,000
26,000,000
26,000,000
20,000,000
24,000,000
89,000,000
§ 100 yrs.
@ 10 yrs.
@ 10 yrs.
€ 100 yrs.
§ 100 yrs.
§ 30 yrs.
8) State Acceptance.
The State of Wisconsin is in agreement with the selection of
Alternative 3A for remediation of the Moss-American Site and has
provided U.S. EPA with a letter of concurrence.
9) Community Acceptance.
Public response is addressed in the attached Responsiveness
Summary.
9.
The Selected Remedy
Based on the findings of the RI/FS, and the evaluation of the
nine criteria, U.S. EPA and the State of Wisconsin have
identified Alternative 3A as the selected remedial alternative
for the cleanup of the contaminated soil, sediment, and
groundwater at the Moss-American Site. Alternative 3A represents
the best balance among the evaluation criteria and satisfies the
statutory requirements for protectiveness, compliance with ARARs,
cost effectiveness, and the use of permanent solutions and
treatment to the maximum extent practicable.
Alternative 3A
Time to Implement:
Capital Cost:
Annual O&M Cost:
Total Present Worth Cost:
3-4 years
$25,000,000
$ 130,000
$26,000,000
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35
Major components of the selected remedy are the following:
On-site soil
* Remove and treat highly contaminated AOC on-site soil;
* Dispose of treatment residue from soil and sediment
back on-site, cover and revegetate;
* Remove and treat Northeast Landfill soil in treatment
unit along with AOC soil and sediment, dispose of
treatment residue in AOC along with AOC treatment
residue and consolidated soil.
Sediment of the Little Menomonee River
* Construct a new channel for the Little Menomonee River;
* Remove and treat highly contaminated sediment from the
old channel;
* Cover old channel with soil from the new channel,
revegetate;
* Restore and mitigate river corridor, habitat, wetland,
and woodland areas;
Groundwater
* Construction of a groundwater collection and treatment
system that will function both separately and
dependently with the biological treatment system.
The selected remedy provides treatment for all three contaminated
media associated with the Moss-American Site. The treatment
methods proposed address the principal threat at the Site as well
as reduction of all site-related contaminants to health-based
levels. The treatment meets the remediation goals for cleanup of
the soil, sediment and groundwater outlined in the FS.
9 . 1 REMEDIATION GOALS AND CORRESPONDING RISK LEVELS
9.1.1 On-site Soil
The remedial goals for soil are to minimize the threats to human
health and the environment from on-site contaminants via the
exposure pathways of direct contact, inhalation or ingestion and
to prevent further migration into the groundwater and
subsequently into the river. Because no chemical-specific ARARs
have been defined for CPAHs, the concentration level that
correlates to the 1 x 10~4 risk level was selected as the
contaminant specific goal for soil. The contaminants specific
goal, 6.1 ppm CPAHs, falls within the lower concentration range
required by the Treatability Variance.
To achieve these goals, 80,000 cu/yds of "highly contaminated" or
target concentration soil including the Northeast Landfill area,
will be excavated and treated on-site. The removal criterion of
"highly contaminated" soil equates to an EO level of 1000 ppm or
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36
greater, or the presence of tarry or oily material and/or a
creosote odor. The removal of highly contaminated soil is also
expected to remove all material that exceeds a risk level of 1 x
10~4, which equates to 6.1 ppm CPAHs in soil. This criterion
was developed with the intent of removing the contaminated soil
and sediment with the greatest migration potential, that which
contains free or visible product.
The biological treatment proposed will reduce the contaminants
levels in all treated media not only to the range permitted under
the Treatability Variance, but to the specific target cleanup
concentration of 6.1 ppm CPAHs or less. The goal is to reduce
all on-site contamination, including the treatment residue, to
the acceptable risk level of 1 x 10~4 or less.
9.1.2 Sediment of the Little Menomonee River
The remedial action goals for the sediment are to minimize direct
contact or ingestion of contaminants in sediment, minimize acute
and chronic effects on aquatic life posed by contaminants, and to
minimize migration of contaminants downstream to the Menomonee
River and ultimately to the Milwaukee Area of Concern as defined
by the regional draft Remedial Action Plan (RA) submitted to U.S.
EPA by the WDNR.
These goals will be achieved in two ways. A new channel for the
river will prevent contact with, or ingestion of, contaminated
sediment by human or aquatic life. Excavation of 5,200 cu/yds of
sediment in the old channel, and subsequent treatment on-site
with the on-site soil, will not only prevent contact, but also
migration of contaminants downstream.
The target concentrations and the volume of sediment requiring
excavation is, as with the soil, determined by the human health
risk. A risk level of 1 x 10~4 for sediment correlates to 388
ppm CPAHs. This means that CPAH levels for sediment left in
place and covered will be 388 ppm or less. While this level is
acceptable for humans, it may not be sufficiently protective of
aquatic life and far exceeds the SCQ recently developed by the
WDNR. The SCQ, set at 3.0 ppm, correlates more closely with the
1 x 10~6 human risk level. A new channel for the river, even
though it will necessitate a temporary loss of some wetland
areas, will, in the long term, be more protective of aquatic
habit.
9.1.3 Groundwater
The remedial action goals for groundwater are to prevent release
of contaminants through the surficial groundwater aquifer to the
Little Menomonee River surface water or sediment and remove
contaminants from groundwater such that concentrations do not
exceed those established in ch. NR 140 of the Wis. Adm. Code.
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37
These goals will be accomplished by physical means and
treatment. A vertical geophysical barrier placed parallel to the
west bank of the river will prevent groundwater contaminants
from reaching the river while the remedial action is in progress.
During the treatment process, free product will be collected,
removed by an oil/water separator and disposed of in an off-site
incinerator. The extracted groundwater will be treated until the
level of the target compounds, B-E-T-X, are less than the PAL.
Groundwater quality will be evaluated in increments of 5 years to
determine if the remedial action objectives have been met. If,
after the ground-water operable unit has been operating for a
minimum of 5 years, it becomes apparent that it is not
technically or economically feasible to achieve the PAL, then a
WACL may be established. The WACL that is established may not
exceed the ES for that compound.
Groundwater collection and treatment will be required until it
can be demonstrated that the concentration of all groundwater
contaminants have been reduced to levels that do not attain or
exceed applicable NR 140 standards. The period of groundwater
collection and treatment is estimated to be less than 10 years.
Treated water will be discharged to the metropolitan sewer if
possible. Discharge levels for the Jones Island POTW require
that the discharge contain less than 5% VOCs. The POTW must be
in compliance with all applicable environmental regulations in
order to receive the discharge. If it is impossible to discharge
to the sewer at the time the remedy is implemented, treated water
will be discharged to the river. Effluent limits for a river
discharge set by the State of Wisconsin are:
Chemical
Ethylbenzene
2,3,7,8-TCDD
Chloroform
Total CPAHs
Daily
Maximum
ppm
45
29
Monthly
Average Limit
flb/dav)
200
1.9 x 10-9
1.6
1.9 x 10-3
Annual
Average Limit
Qb/vear)
6.9 x 10-7
0.68
9.2 Individual Components of the Proposed Remedial Action
9.2.1 Treatment: The bioslurry treatment is a two part process,
The soil will be screened to remove oversized debris. Next, the
soil is washed in an attrition scrubber and separated from the
rest of the material in the screw classifier. The washed soil
that meets clean up levels will be placed back on-site.
Oversized material will be treated according to Best Management
Practices and disposed of on-site in the RCRA compliant unit.
The volume of this material is estimated at 500 - 3000 cu/yds.
The remaining soil will be pumped to the slurry bioreactor along
with the sediment for treatment.
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38
Slurry bioreactors treat contaminated soil by slurrying it, then
mixing the soil slurry with microorganisms in an aerated
reactor. Nutrients can be added to enhance degradation.
Following degradation in treatment tanks, the slurry will be
dewatered before replacement on-site, while the liquid phase
will be recycled. Dewatered soil and sediment (treatment
residue) meeting cleanup levels will be covered on-site along
with the remaining soil. Treatment residue not meeting cleanup
levels will be retreated.
Treatment residue generated from the slurry bioreactor, and
contaminated soil exceeding the 10~^ target concentrations will
be contained on-site and covered with 2 feet of soil and 6 inches
of topsoil. This will include treatment residue generated from
treatment of contaminated soil from the Northeast Landfill
(approximately 1,000 cu/yds).
9.2.2 Rerouting of the River: The new river channel will be
constructed parallel to the existing channel. Construction of
the new river bed will proceed from the railroad tracks just
south of Brown Deer Road to the confluence of the Little
Menomonee River and the Menomonee River downstream of the site.
The river will then be diverted to the new channel. Following
the diversion of the river, the old channel will be drained and
highly contaminated sediment removed before backfilling the 'old
channel. Refer to Appendix B of the FS for a discussion of
possible construction techniques and approaches. The removal
equipment will load the sediment into a lined truck for hauling
to the site for treatment.
The proposed river realignment, illustrated in Figure 7, will
require a detailed design study to assess the river hydraulics,
effects on the wetland and woodland environment, and the effects
on existing parkland and utilities. Consideration for
enhancement of environmental quality and aesthetics will be
addressed as well in the preliminary design phase. Construction
of the channel will comply with ARARs and guidance provided by
the WDNR.
9.2.3 Soil and Sediment Removal: Highly contaminated soil
(80,000 cu/yds) and river sediment (5,200 cu/yds) will be
removed and treated on-site using the slurry bioreactor
technology. The removal criterion is 6.1 rog/kg of CPAHs in soil
and 388 mg/kg in sediment which correlates to the risk level of
1 x 10~4 for both media. The removal criterion methodology will
be further defined in the design phase of the remedial action.
9.2.4 Cover: Treatment residue generated from the slurry
bioreactor, and on-site contaminated soil exceeding the 1 x 10~6
target concentrations, a total of about 210,000 cu/yds, will be
contained on-site by covering it with 2 feet of.soil and 6 inche
of topsoil. The cover will be vegetated to reduce erosion and
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improve aesthetics. To further reduce the likelihood for
exposure to the contained soil and residue, deed restrictions
will be placed on the site to prevent its development and the
area of contained soil will be fenced. The permeable nature of
the cover is intended to enhance groundwater treatment by
flushing out the contaminants while preventing direct contact
with the contaminated soil and sediment. While State RCRA
closure requirements are applicable, an impermeable cap and/or
double liner and leachate collection system will prolong the
groundwater treatment indefinitely. For this reason, pursuant to
CERCLA section 121(d), the Greater Risk to Health and the
Environment waiver will be invoked concerning these State RCRA
requirements, to provide a permeable cover over the treated
material to decrease the time to meet groundwater cleanup
standards.
9.2.5 Northeast Landfill Treatment: Contaminated soil in the
Northeast Landfill, about 1000 cu/yds, will be removed, treated
on-site, and the residue disposed of on-site in the RCRA
compliant unit described above under 9.2.4.
9.2.6 Groundwater Collection and Treatment: Contaminated
groundwater from the west side of the river will be collected by
a series of supplemental drains that lead into an interceptor
drain running parallel to the river, then flowing into a
collection sump. The groundwater treatment system is
illustrated in Figure 9. A vertical barrier, a synthetic
geomembrane liner, will be placed along the east wall of the
main drain trench to prevent discharge of contaminated materials
to the river and recharge from the river to the collection
trench.
9.2.7 Groundwater Monitoring: Groundwater monitoring will be
conducted in the area of the contained soil. Four wells will be
sampled on a quarterly basis and eight others will be sampled
annually.
9.2.8 Preliminary Design Tasks: Refer to the discussion under
Alternative 3A in Section 7 for a list of investigations to be
performed before or during the design phase of construction.
10. Statutory Determinations
Under its legal authorities, the primary responsibility of U.S.
EPA at Superfund sites is to undertake remedial actions that
achieve adequate protection of human health and the environment.
In addition, Section 121 of CERCLA, establishes several other
statutory requirements and preferences. These specify that, when
complete, the selected remedial action for this Site must comply
with applicable or relevant and appropriate environmental
standards established under Federal and State environmental laws
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unless a statutory waiver can be justified. Pursuant to Section
121 of CERCLA, the selected remedy must be cost effective and
utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable. Finally, this statute includes a preference
for remedies that employ treatment that permanently and
significantly reduces the volume, toxicity or mobility of
hazardous wastes as their principal element. The following
sections discuss how the selected remedy meets these
requirements.
10.1. Protection of Human Health and the Environment
The selected remedy protects human health and the environment by
combining source removal and treatment with containment and
short term Site access restrictions, thus significantly reducing
the risks posed by direct contact, inhalation, or ingestion of
Site-related contaminants.
Highly contaminated soil and sediment will be excavated, and
treated biologically to health based levels. The treatment
residue and consolidated soil will be disposed of on-site in the
AOC and covered to prevent contact. Sediment remaining in the
old river channel after excavation will also be covered. The
groundwater treatment system, oil/water separation and carbon
absorption/biological treatment, will reduce the level of
groundwater contamination to below health based levels which is
also protective of the environment.
The remedy, when implemented will reduce all site-related risks
to human health, currently estimated at 1 X 10-4 to 2 X 10-2, to
health based levels and an acceptable risk range of 1 X 10-4 to 1
X 10-6. The remedy will also be protective of aquatic habitat
and the river corridor by providing a clean channel for the
river.
Any short term risks associated with excavation of contaminated
materials can be controlled by the use of good construction
practices.
10.2. Attainment of ARARs
The selected alternative will meet all Federal and State ARARs
unless waived pursuant to Section 121(d)(4)(B). The major ARARs
are presented below.
10.2.1. Action-specific ARARs:
Action specific ARARs are requirements that define acceptable
treatment and disposal procedures for hazardous substances.
Waste on the Site is listed under RCRA as Hazardous Waste, K001
and U051.
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- RCRA 42 U.S.C. Section 6901 et. sea.
Because soil, debris, and sediment containing listed hazardous
waste will be extracted, treated and redeposited within the AOC
or transferred from the Northeast Landfill area during the
remedial action, placement and disposal will occur triggering
RCRA requirements, including LDR 55 Federal Register 8758. The
selected remedy will comply with standards contained in the State
authorized RCRA program and in the self-implementing Federal
requirements promulgated pursuant to HSWA with the following
exceptions and/or modifications:
Land Disposal Restrictions (LDR) 40 CFR Part 268
For disposal of treatment residue from both the Northeast
Landfill and the AOC, LDRs will be met through attainment of
cleanup levels established through a Treatability Variance
obtained under 40 CFR 268.44. Refer to Table 3 for specific
cleanup levels.
State Minimum Design, Operational, and Closure Requirements,
Wis. Adm. Code s. NR 181.44(10)fhl. 181.42(81. and
181.44 f13)
Since these requirements (part of the State of Wisconsin's
authorized RCRA base program apply) to both new and existing
landfills, they would be considered "applicable" due to the
placement of treated soil and debris within the area of
contamination during the remedial action. A waiver under Section
121(d)(4)(B) of CERCLA 42 U.S.C. is invoked for State
requirements concerning design and operation, and closure of
hazardous waste landfills, Wis. Adm. Code s. NR 181.44(10) (h) ,
181.42(8) and 181.44(13), respectively. The waiver is justified
due to the fact that, assuming that the design requirements in
the FS are met and both the cap and/or liner and leachate
collection system are placed over the area of groundwater
contamination, an impermeable cap and/or liner and leachate
collection system will result in a Greater Risk to Health and the
Environment by significantly delaying and reducing the
effectiveness of the groundwater treatment and therefore reducing
the remedial action's effectiveness in reducing risk. The risks
posed by the consolidated materials have been minimized and the
selected cover, a permeable hybrid cover, will enhance treatment
of groundwater contamination by encouraging a flushing action.
The State of Wisconsin concurs with the waiver.
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The State RCRA requirement will be complied with.1
Discharge to Surface Water; Chapter 147. Wisconsin Statutes
This Statute applies to the discharge of any pollutant to the
waters of the State. The selected remedy will achieve State
ARARs for discharge to surface water through discharge to the
POTW or the Little Menomonee River. Treatment residuals, the
pure phase free product and spent carbon, will be incinerated
off-site. The only requirement for discharge to the POTW is that
VOC levels are below 5% and that the POTW has capacity for the
volume discharged. Wisconsin effluent levels for discharge to
the Little Menomonee River are:
Chemical
Ethylbenzene
2,3,7,8-TCDD
Chloroform
Total CPAHs
Daily
Maximum
(ppm)
45
29
Monthly
Average Limit
rib/davi
200
1.9 x 10-9
1.6
1.9 x 10-3
Annual
Average Limit
flb/vear)
6.9 x 10-7
0.68
Air Emission Treatment Requirements (Wis. Adm. Code Chapter NR
445)
The need for air emission treatment such as vapor phase
activated carbon treatment was evaluated based on requirements of
NR 445 and an evaluation of public health risks. Based on the
relative amounts of VOCs in the sediment and soil (only a few
samples had VOC concentrations greater than a few rog/kg),
emission treatment will probably not be necessary. Emissions
will be reevaluated during predesign and air emission treatment
will be included in the remedial alterative if necessary.
10.2.2. Location-Specific ARARs:
Location-specific ARARs are those requirements that relate to the
geographical position of the Site.
1While NR 181.44(10(c) [which prohibits the disposal of
certain waste types, including K001, in landfills] is not an ARAR
since it was not timely noticed and the prerequisite requirements
of 121(d)(2)(c) have not been met, the WDNR Hazardous Waste
Program has indicated in a letter that an exemption from this
prohibition could be granted, under s. NR 181.05, for a non-
Superfund site under similar circumstances, i..e., the same level
of control and protection is provided and there is no increased
threat to human health and the environment. The State of
Wisconsin concurs with this evaluation.
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Flood Plain and Wetland ARARs 40 CFR 264.18fb). Executive Order
11988 and 11990
The requirements of 40 CFR 264.18(b) and Executive Order 11988,
Protection of Flood Plains, are relevant and appropriate to
actions on the Site. To meet these ARARs, the treatment and
containment systems will be located above the 100-year flood
plain and be protected from erosion damage. Contaminated soil
will be moved out of the flood plain before covering.
Executive Order 11990 (Protection of Wetlands) is an applicable
requirement. The selected remedy includes significant excavation
affecting wetlands adjacent to or downstream of the site. ARARs
regarding these wetlands include Executive Order 11990, which
requires that actions at the Site be conducted in a manner
minimizing the destruction, loss, or degradation of wetlands, and
NR 1.95, 115, 116, and 117 which require wetland and floodplain
assessments to be made and submitted to WDNR for review.
These ARARs will be met through the preparation of an extensive
ecological assessment, including aerial photographs, and a
detailed design study to assess the river hydraulics, effects on
the wetland and woodland environments, and the effects on
existing parkland and utilities. This assessment and the design
study will be used in the design phase to develop a plan that
will limit adverse impacts to wetlands as much as possible by
designating areas of least impact, suitable areas for wetland
mitigation and replacement, and determining the quality of
existing wetlands. Consideration for enhancement or
environmental quality and aesthetics will be addressed as well
in the preliminary design phase. This plan will be implemented
as part of the remedial action.
State of Wisconsin Endangered and Threatened Species Protection
Laws
Section 29.415, Wis. Stats., and ch. NR 27, Wis. Adm. Code, are
State Endangered and Threatened Species protection laws which
prohibit the "taking" or harming of endangered or threatened
wildlife resources. These would be applicable to the remedial
action, in that the poisoning of endangered or threatened
species by site contaminants could be considered a "taking".
10.2.3. Chemical Specific ARARs:
Chemical-specific ARARs regulate the release to the environment
of specific substances having certain chemical or physical
characteristics.
Groundwater Quality Standards (Wis. Adm. Code. NR Chapter 140)
The State of Wisconsin is authorized to administer the
implementation of the Federal SDWA. The State has also
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promulgated ground-water quality standards in Ch. NR 140, Wis.
Adm. Code, which, according to WDNR, is being consistently
applied to all facilities, practices, and activities which are
regulated by the WDNR and which may affect ground-water quality
in the State. Chapter 160, Wis. Stats., directs the WDNR to take
action to prevent the continuing release of contaminants at
levels exceeding standards at the point of standards application.
Groundwater quality standards established pursuant to Ch. NR 140,
Wis. Adm. Code, may be PALs, ESs, and/or WACLs. PALs and ESs,
contained in section NR 140.10, Wis. Adm. Code, are generally
more stringent than corresponding Federal standards and,
therefore, are relevant and appropriate to the Moss-American
Site.
Consistent with the exemption criteria of section NR 140.28, Wis.
Adm. Code, a WACL may be established if it is determined that it
is not technically and economically feasible to achieve the PAL
for a specific substance. Except where the background
concentration of a compound exceeds the ES and consistent with
the criteria in section NR 140.28(4)(B), the WACL that is
established may not exceed the ES for that compound.
Groundwater quality will be evaluated in increments of 5 years to
determine if the remedial action objectives have been met.. If,
after the groundwater operable unit has been operating for a
minimum of 5 years, it becomes apparent that it is not
technically or economically feasible to achieve the PAL, then a
WACL may be established in compliance with the criteria in NR
140.28, Wis. Adm. Code. The WACL that is established may not
exceed the ES for that compound.
The point of standards application for PALs and ESs (or WACLs)
under section NR 140.22, Wis. Adm. Code, is any point beyond the
property boundary or any point beyond the design management zone,
whichever is closer to the waste boundary, or any point of
present groundwater use. However, the NCP, 55 Federal Register
8753, provides that groundwater cleanup standards should
generally be attained throughout the contaminant plume or at and
beyond the edge of the waste management area when waste is left
in place.
The implementation of the selected remedy at the Moss-American
Site will be in compliance with Ch. NR 140, Wis. Adm. Code, in
that PALs will be met unless WACLs are established pursuant to
the criteria in section NR 140.28, Wis. Adm. Code, in which case
the WACLs will be met. These standards will be met in accordance
with the NCP, at the waste boundary or wherever groundwater is
monitored.
10.2.4. To Be Considered (TBC)
In implementing the selected remedy, U.S. EPA has agreed to
consider a procedure that is not an ARAR: compliance with
Wisconsin Sediment Quality Criteria (SQC) as shown in Table 4.
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The selected remedy will achieve Wisconsin SQC in order to
fulfill the statutory mandate for protectiveness.
10.3. Cost-Effectiveness
The selected remedy is cost-effective because it provides a high
degree of overall effectiveness proportional to its costs, the
net present worth being $26,000,000. The estimated cost of the
selected remedy is far less than the estimated cost associated
with the best available technology economically achievable
(BATEA) for treatment of PAHs, incineration, and yet the selected
remedy assures a high degree of certainty that the remedy will be
effective in the long-term due to the significant reduction of
the toxicity of the wastes achieved through source removal,
biological treatment and containment of the contaminants in the
soil, sediment, and groundwater that constitute the principal
threat at the Site.
10.4. Utilization of Permanent Solutions and Alternative
Treatment Technologies or Resource Recovery Technologies
to the Maximum Extent Practicable.
The selected remedy represents the maximum extent to which
permanent solutions and treatment technologies can be utilized in
a cost-effective manner for the final remedial action at the
Moss-American Site. A combination of source removal with
biological treatment and containment will significantly reduce
the inherent hazards posed by the contaminated soil, sediment and
groundwater at the Site. Residual contamination at the Site
will be reduced to such levels that the impact on human health
and the environment will be minimal if the containment system
were to fail.
10.5. Preference for Treatment as a Principal Element
The selected remedy eliminates the principal threats at the Site
through biological treatment of highly contaminated soil and
sediment. Contaminated groundwater is also treated through
absorption and destruction of absorbed contaminants by
incineration.
11. Documentation of Significant Changes
The Proposed Plan for the Moss-American Site was released for
public comment in June 1990. The Proposed Plan identified
Alternative 3A, excavation and biological treatment of sediment
and soil, and groundwater treatment, as the preferred
alternative. U.S. EPA reviewed all written and verbal comments
submitted during the public comment period and determined that
the following change be made to the remedy. Since the time the
Proposed Plan was released to the public, U.S. EPA Headquarters
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has determined that a Minimum Technology RCRA (Federal) unit is
not required for the treatment residue from the Northeast
Landfill. Consequently, the treatment residue from the Northeast
Landfill soil will be consolidated with the treatment residue
from the AOC soil and sediment and disposed of within the AOC as
described under Section 9.2. Section 9 of the ROD, which
describes the preferred alternative, has been modified to reflect
this change.
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12. Responsiveness Summary
This Responsiveness Summary has been prepared to meet the
requirements of Sections 113(k)(2)(B)(iv) and 117(b) of the
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980, as amended by the Superfund Amendments and
Reauthorization Act of 1986 (CERCLA), which requires the U.S. EPA
to respond to "...to each of the significant comments,
criticisms, and new data submitted in written or oral
presentations" on a proposed plan for remedial action. The
Responsiveness Summary addresses concerns expressed by the
public, potentially responsible parties (PRPs), and governmental
bodies in the comments received by U.S. EPA regarding the
proposed plan for remedial action at the Moss-American site.
12.1. PUBLIC RESPONSE TO U.S. EPA'S PREFERRED REMEDY
In general there is not a high level of community interest in
the Moss-American site. Despite press releases and Fact Sheet
mailings, the public meeting was poorly attended by local
residents. The majority of those present at the public meeting,
and from whom comments were received, were potentially
responsible parties (PRPs) at the site and their representatives,
and vendors of potentially applicable technologies such as
incineration. The incineration vendors identified themselves as
"local residents" and their comments are included in the
transcript for the public meeting.
Public response and concerns fall into two diametrically opposed
categories. Those who live in the area or have businesses close
by are generally supportive of the proposed action but some want
to be assured that U.S. EPA is cleaning the site up sufficiently.
Some expressed concern for the aesthetic aspects of the remedy
and the environmental impacts of work on the river. When the PRP
comments became public via the media, many concerned citizens
called U.S. EPA to discuss the PRP allegations of "no risk at the
site." Their main concern was that U.S. EPA might decide to do
nothing at the site. Some mentioned the possibility of applying
for a Technical Assistance Grant (TAG) to prevent this from
becoming a reality.
PRP responses include those received from Kerr-McGee [through
their contractor, Weston Inc., and their attorneys]; Milwaukee
County; and the Chicago and North Western Railroad. The general
theme of PRP comments was that the risks were greatly exaggerated
and that no remedial action was warranted. At the very least
they felt that U.S. EPA should continue investigating the site
until in-depth answers were supplied for all unknowns identified
at the site.
12.2. BACKGROUND ON COMMUNITY INVOLVEMENT
Community interest in the Moss-American site dates to 1971 when a
group of young people, wading in the Little Menomonee River while
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engaged in an Earth Day clean up, received chemical burns from
what was later determined to be creosote contaminated sediments
related to site activities. This event brought state and
national attention to the site and sparked a series of
contamination studies and some limited cleanup activities by
State and Federal agencies. Community involvement since that
time has been sporadic and no key community activists have been
identified.
A significant number of comments were generated during the public
comment period in response to the remedial investigation and
feasibility study (RI/FS) reports and the proposed plan for
remedial action at the site. The U.S. EPA has responded to these
comments by combining those that are similar and addressing them
collectively. These comments are divided into comments on the RI
and Risk Assessment, the FS, and those specific to the proposed
remedial action. The commenter has been identified for the most
part, unless the comment was expressed by a number of
commenters.
12.3. SUMMARY OF PUBLIC COMMENTS AND AGENCY RESPONSES
12.3.1. Comments on the Remedial Investigation Report and Risk
Assessment.
12.3.1.1. General Comments
COMMENT: Several commenters expressed concern that the RI did
not characterize the nature and extent of contamination
sufficiently to evaluate and select an appropriate remedial
action for the site.
U.S. EPA's Response: The purpose of the RI (and FS) as stated in
the National Contingency Plan (NCP) is to assess site conditions
to the extent necessary to select and implement a remedy as soon
as possible in order to be protective of human health and the
environment. The NCP reflects a bias for action. U.S. EPA
believes that, while the remedial investigation does not provide
answers to all questions regarding the nature and extent of
contamination, it was performed to a sufficient level of detail
and was sufficiently comprehensive to determine the need for
remedial action and to evaluate remedial action alternatives.
COMMENT: Some commenters were concerned that the estimated risks
to public health and environment were overly conservative and
therefore exaggerated. Alternatively, other commenters expressed
support for the most conservative approaches to protection of
public health and the environment.
U.S. EPA's Response: Risk characterization involves making a
number of assumptions, many of which are conservative.
Conservative assumptions result in higher estimated risk. It hat.
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been U.S. EPA's policy to adopt conservative assumptions when
matters of public health or protection of the environment are of
concern, and therefore be more protective.
12.3.1.2. Specific Comments
COMMENT: The Risk Assessment was not developed in accordance
with the relevant guidance for assessment of health risks.
The exposure scenarios were unrealistic and overly conservative,
do not follow U.S. EPA guidance, and significantly overstate
health risks. (Kerr-McGee)
The use of maximum soil concentrations to determine an upper
bound of risk is inappropriate and inherently assumes that all
exposure could somehow occur based on the highest detected level
in a single location. This provides inappropriately elevated
risk estimates and conflicts with current U.S. EPA guidelines,
which specifically recommend a reasonable maximum approach.
(Kerr-McGee)
Incidental soil ingestion represents the major pathway of
exposure to soils and sediments. This pathway was not evaluated
in a manner consistent with current U.S. EPA guidance. (Kerr-
McGee)
A residential scenario was assumed in defining possible risks
despite the fact that this property is industrial zoned and is
partially located in the floodplain and wetlands making
residential development exceedingly unlikely. In such
circumstances, U.S. EPA's Risk Assessment Guidance for
Superfund: Human Health Evaluation Manual Part A Interim Final
(July, 1989) specifically states that use of a residential
scenario for risk assessments for that type of property is
inappropriate. (Chicago and Northwestern Railroad)
U.S EPA's Response: The Risk Assessment for the Moss-American
site was in progress prior to the release of U.S. EPA's Risk
Assessment Guidance For Superfund/Human Health Evaluation Manual
Part A Interim Final. July 1989, OSWER (OS-230), 9285.701A Pre-
Publication Copy" (RAGS), and was prepared in accordance with
agency risk assessment guidance available at the time referenced
in the RI.
The use of conservative assumptions with regard to uneven
distribution of hazardous substances is addressed in the current
U.S. EPA guidance, RAGS, in section 6.5.3 pages 6-28. The Moss-
American risk assessment presents risks associated with average
and maximum contaminant concentrations to account for the
expected uneven distribution and the existence of areas of high
concentration accessible by the public.
COMMENT: Potency factors used in the computation of carcinogenic
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risk were overly conservative. U.S. EPA endorses the relative
toxicity approach for assessment of carcinogenic contaminants.
This method was not applied and resulted in significant
overestimation of health risks. (Kerr-McGee)
U.S. EPA's Response; The relative potency approach yields more
realistic estimates of risk and has a more sound biological
basis. Furthermore, the relative potency approach is consistent
with U.S. EPA's (1986) guidelines for the assessment of chemical
mixtures when there is inadequate data to assess the mixture
itself. This guidance has an expected release date of 30
September 1990. In addition, the U.S. EPA is due to release a
draft Drinking Water Criteria document in the very near future
which utilizes the relative potency approach and not the uniform
toxicity approach.
COMMENT: PAHs were determined to be the key pollutant
contributing to the risk estimates and driving the cleanup
criteria. The assumption that all carcinogenic PAHs are as
toxicologically potent as B[a]P represents a vast overestimate of
carcinogenic risk, conflicts with current internal U.S. EPA
guidance, and is inconsistent with the Records of Decision (RODs)
for similar sites. (Kerr-McGee)
The EPA report (ICF 1988) also presents a revised potency factor
for B[a]P, effectively lowering its potency by three to four
times. (Kerr-McGee)
It should be noted that the U.S. EPA, in the Integrated Risk
Information System (IRIS) network, has withdrawn the 11.5 potency
estimate and does not have a currently recommended value. This
is further evidence that the U.S. EPA considers 11.5 to be an
overestimate. (Kerr-McGee)
U.S. EPA's Response; The only published guidance for the use of
relative potency is for dioxins and furans. There is no
currently adopted guidance for a relative potency approach for
the PAHs.
U.S. EPA's recently proposed rule (40 CFR 141) published in the
July 25, 1990 Federal Register 55 FR 143 30370-30448, which is
out for public comment, lists the option of setting the MCLG for
B[a]P at zero and also the option of setting the MCLGs for
benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene,
chrysene, dibenzo[a,h]anthracene, and indeno[l,2,3-cd]pyrene at
zero because there is sufficient data to classify all seven PAHs
as Group B2, probable human carcinogens.
The same proposed rule cited above also contains proposed MCLs
for the PAHs Of 0.0002, 0.0001, 0.0002, 0.0002, 0.0002, 0.0003,
and 0.0004 mg/1 respectively. Given that the establishment of
MCLs is not strictly health based but includes analytical
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capability, these proposed limits may or may not be useful in
determining the relative potencies of the other PAHs. Such a
minute difference between the relative toxicity of the various
carcinogenic PAH would not seem to warrant separate derivation of
risks nor support the rationale of not using the same slope
factor for B[a]P in calculating the risk for all carcinogenic
PAHs found.
The ICF report published as a final report in 1987, with a
proposed B[a]P potency of 6, differs from the interim final
report prepared by ICF in 1988 with a proposed potency of 3. It
is not widely accepted within U.S. EPA that the ICF (1988) report
is the preferred approach to assessment of risk from PAHs.
As of August 20, 1990 the slope factor for B(a)P was still 11.53
as listed in IRIS and has not been withdrawn.
COMMENT: The concentration of PAHs in the lower two reaches of
the Little Menomonee River were lower than U.S. EPA documented
background concentrations. (Kerr-McGee)
The total PAH concentrations in the sediment samples downstream
from the Moss-American site average between 10,700 to
250,000 ug/kg. However, average concentrations of total PAHs in
stream reaches 4 and 5 are 18,400 and 10,700 ug/kg respectively,
which are within the average range reported for background data
in Appendix J of the Feasibility Study. This clearly suggests
that only the first three stream reaches may contain elevated
concentrations of PAHs compared to the background data. EPA
guidance requires consideration of this fact, but EPA has failed
to do so. (Kerr-McGee)
U.S EPA's Response; The key word here is average. While average
PAH concentrations in the last two reaches are less than for the
upstream reaches, data from river reconnaissance suggests that
there may be pockets of highly contaminated sediment, hot spots,
in these latter two reaches. The background level for
carcinogenic PAHs, calculated from samples collected upstream of
the site and from tributaries, was estimated at 18 ppm or 18,000
ug/kg. Sediment samples taken from the two lower reaches of the
river were found to contain carcinogenic PAHs above this level.
The proposed remedial action specifies that additional sampling
be performed to determine what areas will require removal. Refer
to Appendix J of the FS report for details of the background
sediment sampling effort as well as estimates of background
concentrations based on six different groupings of data.
COMMENT: Cursory review of data utilized in the calculation of
risk identified numerous instances where inaccurate concentration
and risk-related data were used that suggesting (sic) fundamental
errors in calculated risk. (Kerr-McGee)
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The original risk assessment calculated soil ingestion without
taking into account certain modifying parameters, such as the
fraction of soil ingestion during a typical day that would be
from the contaminated source. These exposures were recalculated
using the most recent U.S. EPA guidance (EPA, 1989).
Target concentrations calculated by Weston for carcinogenic PAHs
in sediment indicate that remedial action in the Little Menomonee
River is not warranted. (Kerr-McGee)
U.S. EPA's Response: As stated earlier, the risk assessment was
performed in accordance with the guidance that was in effect at
that time. The assumptions used by Weston, specifically the
B(a)P potency value from ICF, have not been peer reviewed and are
not in use in current guidance. The EPA believes that remedial
action for the river is warranted.
COMMENT: A cleanup criteria of 100 ppm for carcinogenic PAHs
(CPAH) in residential soils has been issued by the U.S. EPA at
several sites. This 100 ppm level is higher than the target
cleanup concentrations for soils using the revised exposure
assumptions and toxicity information. This supports the
contention that the revised [Weston] risk assessment is still
conservative. (Kerr-McGee)
U.S. EPA's Response: The development of cleanup criteria is
normally a site-specific procedure. U.S. EPA has not developed
standardized cleanup criteria for PAHs, nor has it been EPA
policy to base cleanup criteria for new sites on criteria used in
preceding RODs. While CPAH levels of 100 ppm or greater have
been applied as cleanup criteria at other sites, these were
usually accompanied by caveats such as institutional controls or
other limitations that reduce potential risk. These should be
noted when citing cleanup levels.
COMMENT: The soil concentration referenced [in the risk
assessment] were the highest detected concentrations without
regard to where these concentrations were detected.
Consequently, the risk assessment hypothesizes direct exposure
and inhalation exposures to surface soils while using subsurface
soil analytical results. (Chicago and Northwestern Railroad)
U.S. EPA/s Response: The exposure scenario assumes that
subsurface soil could be excavated and replaced as surface soil.
Samples not considered representative of surface conditions (or
potential surface conditions) were excluded from use in the risk
assessments.
COMMENT: The risk assessment performed by U.S. EPA acknowledges
that no RfD's were exceeded under any of the postulated exposure
situations. That fact does not appear to have been addressed in
the FS evaluation of remedial alternatives.
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U.S. EPA's Response: The FS focused on the principal threat at
the site, the contaminants of concern, i.e., the carcinogenic
PAHs. The fact that no RfD's were exceeded at the site is
inconsequential to the choice of remedy.
COMMENT: Comparison of the reported data for onsite soils and
sediment with the background data suggests that several of the
[inorganic] contaminants selected as chemicals of concern may not
be site-related (i.e. background levels were not exceeded).
These contaminants should not be included in the risk assessment.
(Kerr-McGee)
U.S. EPA's Response: Inorganics contributed a very small
fraction to the overall risk estimates at the site.
COMMENT: [Current EPA guidance] recommend[s] considering risks
from nonsite-related anthropogenic sources separately so that
decision makers can more appropriately [evaluate risk]. Data
available from a variety of sources throughout the United States
(ATSDR, 1990) indicate that these [PAH] concentrations can be
relatively high. Table 2-3 presents some typical background
soil concentrations reported in the literature... and shows that
for several of these carcinogenic PAHs, the upper end of the
range for the site is lower than the upper end of the range
listed for urban soils. (Kerr-McGee)
U.S. EPA's Response; Aside from the fact that the table
presented by Weston is incomplete in that it does not list
concentrations for 7 PAHs observed at the Moss-American site, it
would seem that the use of values from regions that are hundreds
or thousands of miles from the site is less useful than site-
specific background information collected in the vicinity of the
site. The results of background soil samples taken during the RI
found PAH concentrations near or below the detection limit of the
analyses (p. 3-4 of RI report).
The U.S. EPA recognizes the importance of defining background
levels for sediments and assumed that the grouping that included
samples from tributaries to the Little Menomonee River would be
used in the estimation of background. The EPA also believes that
additional background sampling should be performed if background
levels are used as a basis for remediation. The results obtained
to date are considered adequate for the purposes of the RI/FS.
COMMENT: Although some effort was taken to ensure the background
samples contained high silt, several samples were taken in gravel
and sandy stream segments which would not be expected to have
high natural levels of PAH compounds. As a result, the results
of the background sampling may underestimate, the background
levels in the watershed. (Kerr-McGee)
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U.S. EPA's Response; Not true. The sediment samples described
as being sand are samples SD05, SD07, SD08, SD09, SD10, and SD11.
Except for SD05, these samples were taken from the Menomonee
River and were not used in the background calculation. SD05
exhibited higher values than the samples taken upstream of Brown
Deer Road and cannot be construed as lowering the estimated
background levels.
COMMENT: The recreational scenario assumes that children or
adults may come into contact with contaminated sediment in the
Little Menomonee River...There is no evidence to support the
recreational use of the Little Menomonee River, that EPA has
assumed....Based on a Weston survey by a field team of the river,
the exposure scenario relative to the recreational use of the
river is overly conservative. At a time of year that it might be
expected for local residents to make recreational use of the
river, no evidence could be found, even at the road bridge
crossings, that would support a scenario for ingestion of
0.1 g/day of sediment for 40 days/year for 10 years. The
vegetation cover renders the river virtually inaccessible for
much of the reach downstream of the site to the Menomonee River.
Indeed, the bike paths laid out through the park appeared well
used, but there was no evidence of casual access to the river
leading from these paths through the dense vegetation.
Furthermore, the acknowledged patchy nature of the PAH
contamination and the absence of obvious releases of odor of
supposed deposits, bring into question the acute exposure to PAHs
assumed by the risk scenarios relating to the river. (Kerr-McGee)
U.S. EPA's Response; Weston's observations totally contradict
observations made by U.S. EPA staff during numerous site visits,
the observations made by U.S. EPA contractors during sampling
episodes conducted throughout the river over an extended period
of time, and comments received from local residents regarding
their perceptions of children's access to the river. A well-used
foot path runs along the west side of the Little Menomonee River
adjacent to the site. Numerous foot paths lead from the roads
and bike path to the river in the downstream stretches. Taking
into account first hand observations and comments of residents,
U.S. EPA believes that assumptions regarding casual access are
not overly conservative.
In addition, since the county has plans to develop the site into
a usable park facility as was noted in Weston's comments, the
potential for future development of the parkway to make it even
more accessible is significant. The 3-day observation by the
Weston field team, during a period when rainstorms occurred on
two of the evenings (according to Weston's comments) in which
residents could be reasonably expected to avoid recreating in the
wet and muddy conditions at the site, is not.considered a
reasonable basis to discount the recreational use scenario.
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COMMENT: The repeated references throughout the available
reports to a single incident 20 years ago of skin contact leading
to what is variously described as x*skin burns'' and x*skin
irritations'7 serve to exaggerate the significance of the
potential effect. On the basis of the [Weston] field team visit,
such impacts are very unlikely. (Kerr-McGee)
U.S. EPA's Response; Direct contact dermal exposure, with its
potential for burns, or skin irritations, was not evaluated as a
risk and was not the basis for determining the need for remedial
action on the sediment. Skin irritations and burns, apparently
from exposure to contaminated sediment, were documented in the
past and so were referenced in the RI and FS reports; the
potential for such an occurrence under the no action scenario
remains a concern to the EPA.
COMMENT: The exposure assumptions used in the Risk Assessment
for the Moss-American site should be modified to include:
— Recent U.S. EPA guidance (U.S. EPA, 1989) on
calculating soil ingestion
— Upper 95 percent confidence intervals or some other
reasonable measure of maximum exposure and not maximum
soil concentrations (U.S. EPA, 1989)
— More reasonable maximum exposure assumptions, or at
least appropriate documentation for the ones used.
— The use of a two-hour exposure duration for inhalation
exposure when exposure is assumed for two hours.
— Consideration of carcinogenic metals inappropriately
excluded. (This is more conservative than original
assessment).
— Appropriate noncarcinogenic inhalation criteria.
These recommendations are all based on U.S. EPA guidance or
criteria. The EPA risk Assessment does not follow such guidance
and criteria and must clearly be modified. Such modifications
would result in a proper estimate of the %xreasonable maximum''
risk. The exposure modifications alone yield estimated risks
that are significantly lower than those calculated by the EPA.
Both carcinogenic and non-carcinogenic risks are between one and
three orders of magnitude lower than those presented in the EPA
assessment. (Kerr-McGee)
U.S. EPA's Response; Results of the revised estimates proposed
by Weston do not clearly show that a revised estimate performed
according to the most recent, revised guidance would estimate
risk levels lower than the limits typically assumed to be the
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minimum acceptable risk (i.e., the range of carcinogenic risk is
1 x 10~4 to 1 x 1 x 10~6, with 1 x 10~6 being the point of
departure used by U.S. EPA for determining remediation). The
Weston Table C-3, for example, denotes a revised estimated risk
level of 2.2 x 10~3 based upon maximum concentrations, and
4.9 x 10~5 based upon geometric mean concentrations. It is
unclear whether the use of the 95 percent upper confidence limit
average concentration was employed as Weston had recommended
earlier. Moreover, a cursory comparison of revised target
concentrations (Table 6-1, Weston) against the upper 95 percent
confidence concentrations (Table 2-3, Weston) suggests that the
upper end range values exceed the proposed 1 x 10~4 targets.
12.3.2 Comments on the Feasibility Study Report
12.3.2.1. Specific Comments Related to Groundwater Remediation
COMMENT: The RI previously concluded that there was no real
aquifer so EPA must have defined the vertical component of the
groundwater regime. If the Agency is uncertain as to the nature
of the groundwater flow, then its RI was clearly inadequate and
its proposed pump and treat systems, and associated cost
analyses, can have no validity. (Chicago and Northwestern
Railroad)
U.S. EPA's Response; While some degree of uncertainty exists in
any assessment of the nature of groundwater flow, groundwater
level measurements collected during the RI indicate that
groundwater from the site is flowing to the Little Menomonee
River. The objectives for remediation of groundwater are to
attain ARARs for groundwater quality, and to prevent the
discharge of creosote and dissolved PAHS to the Little Menomonee
River. These objectives are consistent with guidance provided in
CERCLA and the NCP.
The FS recognizes that the dissolved phase of the principal
contaminants of concern in groundwater, i.e., PAHs, will tend to
travel very slowly due to their hydrophobic nature and the low
hydraulic conductivity on the site. Data gathered during the RI,
however, indicates that contaminants are migrating into the
Little Menomonee River, albeit at a very slow rate. Data also
indicates that concentrations of several compounds present in the
groundwater exceed Wisconsin Department of Natural Resources
(WDNR) groundwater quality standards. Based on this information,
the U.S. EPA believes action to remove contaminants, thereby
aiding the rehabilitation of the aquifer and preventing migration
to the river, are warranted.
COMMENT: The treatment system could require operation for tens
of millions of years to achieve cleanup objectives. (Kerr-McGee)
U.S. EPA's Response: Without the removal of source material
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(pure phase), the release of PAHs into the groundwater could
continue for an indefinite period. Therefore, the preferred
alternative provides for removal of much of the source material.
The removal would be performed in conjunction with monitoring to
verify the effectiveness of remediation and determine whether
continued groundwater collection and treatment will be necessary.
The U.S. EPA does not believe, however, that no action should be
taken even if an extended period of groundwater collection were
required.
COMMENT: There is inadequate data to define the area of
(groundwater) contamination. The U.S. EPA should provide a more
detailed and more comprehensive study of groundwater
contamination or explain how the nine point remedial alternative
screening would be affected by variation in volume of
contaminated groundwater.
The major remedial action goal of the proposed cleanup at the
Moss-American site is to prevent the transport of contaminants to
the Little Menomonee River. The present review has identified
the following reasons why the proposed cleanup will not achieve
the stated goal:
• The extent of groundwater contamination has not been
defined.
• The contaminants at the Moss-American site sorb to soil
rather than flowing with groundwater and, therefore,
will migrate much less than implied in the FS.
• The chemistry of DNAPLs assures that complete source
removal is probably impossible by means of excavation.
• The strong affinity of PAHs for soil will require that
the proposed groundwater collection and treatment
system will require millions of years to meet cleanup
objectives.
Because contaminants are nearly immobile, the potential for
expansion of groundwater contamination is not significant...
(and) the proposed groundwater collection system design should be
rejected as unnecessary and ineffective. (Kerr-McGee)
U.S. EPA's Response; it should be noted that the "nearly
immobile" contaminants at the site have, over a period of years,
grossly contaminated the sediment of the Little Menomonee River,
which would indicate that the "potential for expansion of
groundwater contamination" is significant. The RI recognizes
that the extent of groundwater contamination has not been
completely defined. This definition will occur during remedial
design, as will as evaluation of additional groundwater
remediation measures. The nature and extent has been defined
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sufficiently to require that remedial action be performed on the
groundwater, and that the remedial action plan presented in the
FS report would not be altered significantly if the extent of
contamination is greater than currently estimated.
The FS recognizes the strong affinity for the contaminants of
concern for adsorption to soil. U.S. EPA finds no fault in its
own evaluation of contaminant transport. More importantly, the
Weston comment supports U.S. EPA's conclusion that, if left in
place without action, the pure phase creosote will provide a
long-term source of groundwater contamination and therefore
should be removed.
COMMENT: The FS addresses the location of the "contaminant
mass" in relation to the water table inconsistently. Page E-3
states that the large volume of the contaminant mass is below the
high water table and page G-5 reiterates that conclusion.
However, on page H-10, the FS concludes that much of the
contamination is above the high water table. This inconsistency
is significant in that the Agency uses the relationship of the
water table to the contaminant mass as a basis to retain or
reject remedial alternatives. For example, U.S. EPA rejects soil
flushing as an option due to the location of the contaminants
below the water table. (Chicago and Northwestern Railroad)
U.S. EPA's Response; The apparent inconsistency can be clarified
by restating that contaminated soil (with relatively high
contaminant concentrations) exists both above and below the water
table. A more quantitative assessment of the relationship
between contaminant mass and water table was not performed
because a qualitative assessment was adequate to evaluate the
applicability of remedial technologies. Soil flushing, for
example, is not considered an appropriate remedial technology for
this site due to the low permeability of the saturated zone, not
only because contaminant mass was found below the water table.
12.3.2.2. Specific Comments Related to Volume Estimates of
Contaminated Soil and Sediment.
COMMENT: The volume of contaminated soil and groundwater may be
grossly inaccurate, thereby casting the assessment of the
remedial alternatives into doubt. (Kerr-McGee)
The effectiveness of the proposed cleanup plan is highly
dependent upon the volume of contaminated material to be
treated. There are many data gaps and irreproducible numbers in
the EPA volume estimates which, if not resolved, could render
proposed cleanup technologies inappropriate. (Kerr-McGee)
The shortcomings of the RI also render the relative cost analysis
within the FS unsupportable since the volume of materials
addressed under each remedial alternative is impossible to define
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with the available information. (Chicago and Northwestern
Railroad)
U.S. EPA's Response: The degree of uncertainty in the estimated
volume of soil and groundwater requiring remediation will not
impact the choice of the remedial alternative as the volume of
material requiring processing is only one aspect of the
evaluation of remedial alternatives. If the volume of highly
contaminated soil or sediment is substantially greater than
estimated, the estimated cost to perform the remedy would
increase, but the increased volume and associated costs should
not make the proposed remedy any less effective. The cost to
remediate is only one of nine criteria evaluated in the FS and is
less important than the protection of human health and the
environment.
Moreover, Weston's own comments do not to bear out the
relationship between estimated volume and impact on
effectiveness. Weston has acknowledged in the comments that an
independent check on the volume calculations revealed that "To a
reasonable degree of accuracy, the volume figures check,
particularly if selective excavation of visibly contaminated soil
is not especially efficient." This comment suggests that the
volume estimates are reasonable if not conservative.
COMMENT: The proposed cleanup approach has assumed that visible
PAH contamination will be removed from the river bed. No visible
contamination was observed by trained Weston personnel anywhere
downstream from the site during field work in July 1990 and U.S
EPA laboratory data showed concentrations well below levels that
would likely be visible. (Kerr-McGee)
U.S. EPA's Response: Visible contamination in the form of
creosote oil was observed by experienced CH2M Hill geologists and
technical field personnel (U.S. EPA's contractor) during RI
fieldwork and is so noted in the field notes. The stated
objective of Alternative 3A is to remove and treat the most
highly contaminated soil and sediment. The FS used information
as to the observed locations of visible traces of oily materials
as an indication of areas that were likely to be highly
contaminated.
The FS does not establish "visibly contaminated" as the cleanup
criterion. The U.S EPA recognizes that the use of qualitative
criteria could result in dispute between PRPs and the U.S. EPA
during the RA, and has developed a quantitative criterion that
will be further refined during RD. The U.S. EPA assumed in the
FS that the visual measure would be employed unless such a
dispute occurred. The comment provided by Weston serves to
confirm the EPA's conclusion that a more quantitative measure
will be necessary to verify effectiveness of remedial actions.
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COMMENT: The FS also does not contain any discussion of the fact
that much of CNW's portion of the property is already paved with
asphalt and fenced. The fact that there is a clay barrier wall
between the CNW property and the Little Menomonee River is also
totally ignored in the FS. (Chicago and Northwestern Railroad)
U.S. EPA's Response; The FS report, Chapter 1, depicts the
asphalt parking lot and discusses the clay cutoff wall. These
physical characteristics were not addressed in detail as they
were not considered significant impediments to exposure or
transport of contaminants as indicated by the fact that the
contamination is currently moving off-site despite the presence
of the parking lot and cutoff wall. The parking lot covers only
a portion of the contaminated soil, and the clay wall is believed
to span only a small fraction of the cross-sectional area of
contaminated groundwater.
COMMENT: The property which CNW owns is currently zoned for
industrial use and based on the location and setting of the
property, it is anticipated that such use will continue. CNW
itself has no intention of selling the property or significantly
altering its current operations at this location. In fact, in
order to eliminate any concern about potential residential
development of the property, CNW is amenable to entering into
institutional controls, such as deed restrictions if appropriate,
to preclude development in the future. (Chicago and Northwestern
Railroad)
U.S. EPA's Response: The use of institutional controls as a
means of protecting public health was considered as a potentially
applicable approach in the FS. The FS reflects EPA's concern,
however, that the use of institutional controls alone may be
inadequate for long-term protectiveness in an area that continues
to become more developed for residential use.
COMMENT: The methods of limited trench dewatering and excavation
do not provide for discovery or removal of deep hot spots of free
product or contaminated soil and groundwater. (A.F. Gallun and
Sons Company)
U.S. EPA's Response: The U.S. EPA recognizes the need for the
development of more detailed plans for soil removal, including a
detailed plan for verification of attainment of remedial goals.
Dewatering methods and costs assumed in the FS will be identified
in greater detail during the remedial design phase.
12.3.2.3. Specific Comments Related To Wetlands Issues
COMMENT: Neither the adverse environmental impacts to flood
plain and wetlands have been considered nor have the costs for
mitigation and restoration been evaluated. (Kerr-McGee)
In the context of Section 404, avoiding impacts means staying out
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of wetland or other waters of the United States. This will not
be possible in the proposed realignment corridor area since much
of the Little Menomonee flood plain appears to be wetlands.
After careful review of the proposed plan to reroute the Little
Menomonee River, it can be concluded that most, if not all, of
the flood plain wetlands will be destroyed during construction.
Compensation for wetlands impacts usually means restoring
previously converted wetlands, enhancing degraded wetland, or
creating wetlands. In the FS report, minimization of
construction activities in existing wetlands was noted as a
means of mitigating riparian habitat destruction in the design of
the new river channel. However, no discussion was given as to
how the wetlands may be restored after construction. The
proposed realignment does nothing towards meeting any of the
conditions for compensation of wetlands impacts, namely restoring
previously converted wetlands, enhancing degraded wetlands, or
creating wetlands since the new alignment is apparently contained
within existing wetlands. (Kerr-McGee)
The Agency has not taken into account the destruction of the
existing land and aquatic plant and animal populations. Nor has
the Agency taken into account the length of time required for
those ecosystems to recover from such destruction, assuming that
recovery is possible. (Chicago and Northwestern Railroad)
Removal of the sediments and construction of a new channel will
cause widespread destruction of the natural habitat of the
corridor. In addition, artificially designed channel features to
restore aquatic habitats usually are difficult to establish until
the channel develops some form of natural sedimentation/erosion
equilibrium. Establishment of wooded vegetation will take
many years further impacting the long-term value of the subject
property [property of A. F. Gallun & Sons]. (A. F. Gallun &
Sons)
U.S. EPA's Response: The potential for adverse impacts on
wetlands was considered at great length in the FS (see
Appendix B). The NCP requirement for a wetlands evaluation is
not explicit regarding the level of detail for such an analysis.
Guidance was provided by the WDNR as to what might be required
for wetlands restoration. The conceptual design presented in the
FS meets the general intent of the WDNR guidance, by providing
for restoration of riparian habitat. The design would also be
conducive to the development of wetlands areas alongside the
pilot channel. Thus, the costs for some wetlands construction
has been accounted for in the estimates. The FS also states that
efforts would be made to route the river in such a manner so as
to minimize the impact on existing wetlands. The preliminary
analysis suggests that routing the river through areas of high
quality wetlands might be avoided. The U.S. EPA realizes that
the time until this constructed area becomes an established
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community will mean a short-term deficit in wetlands areas, but
believes that the remediated river will provide a superior
habitat for aquatic life over the long-term as well as resulting
in a net gain in wetlands.
COMMENT: The NCP and U.S. EPA policy on flood plains and
wetlands assessments (OSWER Directive 9280.002) requires ... an
environmental assessment (in the remedial planning process). In
addition, the NCP and U.S. EPA policy require that a flood
plain/wetlands assessment be performed and integrated into the
feasibility study. Flood plain/wetlands assessments should
consist of a description of the proposed action, a discussion of
its effect, a description of the alternatives and their effects
on the flood plain and wetland and measures to minimize potential
harm to the flood plain/wetland. If the potential alternative is
likely to impact a flood plain or wetland, the agency shall act
to minimize adverse effects and take steps to restore and
preserve the beneficial effects of flood plains/wetlands. The
Moss-American Administrative Records, including the RI and FS
reports, does not satisfy the NCP or current U.S. EPA policy.
(Kerr-McGee)
U.S. EPA's Response; The wetlands in question were described in
the RI report and the impacts to those wetlands for the various
alternatives were described in the FS report. The OSWER
Directive 9280.0-02 states that "flood plain/wetland assessments
shall consist of a description of the proposed action, a
discussion of its effect on the flood plain/wetlands, a
description of the alternatives considered and their effects on
the flood plains and wetlands, and measures to minimize potential
harm to the flood plain/wetland if there is no practicable
alternative to locating in or affecting flood plain/wetlands."
While the policy directive does not identify more specific
requirements for the analysis, it does identify means of
minimizing possible harm to flood plains. The U.S. EPA believes
that the RI and FS documents do satisfy the requirements of the
NCP and current U.S. EPA policy.
The directive also recognizes that benefits such as maintenance
of water quality standards, maintenance of natural systems,
conservation and long-term productivity of existing flora and
fauna, and other uses of-wetlands, including recreational use are
in the public interest. The U.S. EPA believes that the proposed
alternative will produce more potentially high quality wetlands
than currently exist in the Little Menomonee River corridor.
U.S. EPA, in conjunction with the WDNR and the Southeastern
Wisconsin Regional Planning Commission (SEWRPC), is currently
conducting an ecological study at the site that will include an
analysis of the wetlands/flood plain associated with the Little
Menomonee River. The wetlands will be mapped, and sensitive
areas and/or areas with endangered species will be noted so that
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impact can be avoided. In addition, alternative routes that
would avoid or minimize effects on wetlands will be investigated.
COMMENT: The proposed river realignment cannot be justified in
light of minimal risks, the problems of construction, and
concerns for destruction of wetlands. (Kerr-McGee)
U.S. EPA's Response; Given that the risk assessment was
performed in accordance with the U.S. EPA guidance available at
the time, and that carcinogenic PAHs in sediment exceed WDNR's
proposed sediment quality criteria, action on the river sediment
is considered warranted.
The U.S. EPA recognized that construction of a new river channel
would result in adverse short-term effects on the community. The
EPA believes, however, that these impacts will be more of the
nuisance variety, and of a lesser concern than the long-term
risk and deleterious impact of contaminants in the sediment that
probably exists. The U.S. EPA also believes that the action
wherein sediments are removed without river realignment would
also pose major difficulties in construction and could result in
significant destruction of habitat and wetlands.
COMMENT: The FS contains no indication that U.S. Fish and
Wildlife was involved in the assessment of remedial alternatives
for this site. In addition, the FS does not reflect any input
from the Corps of Engineers with respect to the River relocation.
(Chicago and Northwestern Railroad)
U.S. EPA7s Response: The U.S. Fish and Wildlife Service, along
with numerous other agencies, routinely receives for comment the
draft RI and FS for each Superfund site. The Fish and Wildlife
Service has concurred with the preferred remedial action at the
site in a letter dated 8/22/90. The US Army Corps of Engineers
will perform the remedial action if the PRPs are unwilling, or
provide oversight, including design review, if the remedial
action is performed by the PRPs,
12.3.2.4. Specific Comments Related to the Estimated Cost of the
Proposed Remedial Action
COMMENT: Several comments relate to concerns that the cost
estimate lacks sufficient detail and accuracy to provide
estimates that can be used to select a remedy, and that improper
assumptions or incorrect calculations may have skewed the
selection of the remedy.
U.S. EPA's Response: Because the details of the remedial actions
are not yet established at the feasibility study stage, the true
cost of the remedy may be substantially different from the
estimates presented in the Feasibility Study. The estimates,
however, are not required to have a high level of accuracy since
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cost is only one factor of nine to be assessed in evaluating and
selecting an alternative, and has lesser significance than the
two "threshold criteria." The estimates are used to compare the
costs of different alternatives.
COMMENT: Access roads to the public highways will be developed
as will laydown areas for equipment and materials storage. A
second access may have to be constructed on the other side of the
river in certain areas. Due to the wet nature of the area in
which the roads will be constructed, a geonet will have to be
provided under the gravel to maintain a firm base for the trucks
and equipment to travel on. Clearing and grubbing in the FS
estimate does not include disposal of trees and stumps. The cost
estimate for clearing and grubbing needs to be revised to include
stump and material disposal, grading, and erosion controls.
Excavation of the new river bed is predicated in the FS on using
a 1 cubic yard backhoe for the excavation. A different procedure
needs to be followed employing several machines larger than a
backhoe. Similarly, a 1 cubic yard backhoe selected for
construction of roadway crossing transitions is too small. There
will be modification work to the existing tributaries and
drainage swales that is not included in this FS estimate. There
are only minor allowances for dewatering. A well point system
may be required until the backfilling is complete. The FS does
not include costs for the disposal of gravel and geonet required
for access roads. Weather problems, which can complicate the
river relocation project, have not been addressed in either the
original estimate or in this independent estimate. An escalation
allowance for inflation has not been included. Landscaping the
park area after the completion could be a major cost. (Kerr-
McGee)
U.S. EPA's Response: The U.S. EPA recognizes and expects that
some refinements to the cost estimates would be made in a
predesign level of effort as the details for implementation of a
specific design become established. Cost estimates in the FS are
not intended to dictate the approach to construction. FS cost
estimates are to provide relative estimates of the costs to
perform the alternative remedial actions. The FS states that the
expected level of accuracy for the cost estimates is "order-of-
magnitude," i.e. plus 50 to minus 30 percent.
The cost estimate for the selected alternative also includes
$5.5 million dollars in contingencies to address unexpected costs
such as adverse impacts due to weather or dewatering costs
greater than anticipated.
If the independent cost estimate prepared by Weston is compared
to the U.S. EPA estimate, the cost differential is less than
20 percent if the added $1.5 million Weston assumed for
dewatering and $4 million Weston assumed will be required for
wetlands restoration is subtracted. At this time, there is no
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information that clearly indicates that these costs will be
incurred as part of this action. Only portions of the river will
require sediment removal and it may be possible to remove this
sediment without a well point system during dry weather since the
sediment could be fed directly to the reactor as a slurry. The
$4 million wetlands restoration estimate assumes that the
proposed channel design will not contribute to wetlands
restoration. While the intent of the channel design is to
restore a riparian habitat, the U.S. EPA believes that the
channel design would contribute significantly to wetlands
restoration. The specific needs for wetlands restoration could
not be defined during the preparation of the FS. Escalation
allowances are not included in the cost estimates since cost
estimates are to be prepared on a present worth basis (see
Guidance for Conducting Remedial Investigations and Feasibility
Studies Under CERCLA, pg. 4-26). This type of analysis allows
comparisons between the costs of alternatives, which is the
intent of the cost estimate.
In conclusion, the U.S. EPA believes that the cost difference
presented by Weston falls within the order-of-magnitude accuracy
range expected for feasibility studies.
COMMENT: U.S. EPA has adopted a costing scheme that artificially
decreases certain costs making chosen remedial alternatives
appear less expensive than they realistically would be. In its
cost comparisons, U.S. EPA used differing assumptions depending
on the remedial alternatives being evaluated, despite the fact
that the same cost parameters were being addressed in each
instance. It is not substantially documented that the Health and
Safety impacts of incineration are significantly different than
those of bioremediation The health and safety costs of
incineration should therefore be less than those for
bioremediation since incineration requires less time on site.
.... U.S. EPA's category of "other" costs which includes
administration, service, and permitting costs, should also be
calculated as a function of time and contamination present,
rather than percentages of the remedial alternative
cost....U.S. EPA has not sufficiently explained why the
incineration alternative has substantially higher allowances and
contingencies factored into its cost totals. (Chicago and
Northwestern Railroad)
U.S. EPA's Response; Health and safety costs were estimated
assuming an initial capital expense (training, decontamination
pads, development of safety plans, etc.), and, then, an annual
cost (e.g., for a health and safety officer). The only
alternative with a longer estimated remediation period was
Alternative 3B, which would not have personnel on site for
extended periods, and therefore has a decreased cost for a health
and safety officer. The use of percentages for "other" costs is
considered an acceptable method of estimation for this level of
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detail. The percentages used for bid and scope contingencies
were less than and not greater than other alternatives including
treatment.
COMMENT: The FS cost estimate [for the slurry bioreactor],
Table 1-3, makes use of CORA cost data according to the column of
assumptions.... It appears, therefore, that the CORA model costs
should not be used for the FS — a higher level of accuracy is
expected of an FS. (Kerr-McGee)
U.S. EPA's Response; The basis for the cost estimates shared the
same assumptions recently developed for the CORA model. The
reference to CORA in the FS only summarizes the fact that CORA
served as the basis for assumptions related to the line item
operating costs, and equipment costs. U.S. EPA recognizes that
CORA should not be used when more site-specific information is
available. However, because the slurry bioreactor technology has
limited application history at full-scale, there is little
information from which to base cost estimates. Because a
superior database from which to develop estimates was not
available, these same assumptions were retained and the cost
tables list CORA as the source of these assumptions.
12.3.2.5. Specific Comments Related to the Proposed Treatment of
Contaminated Soil and Sediment
COMMENT: Kerr-McGee concludes that the soil washing approach
advocated by EPA is not feasible for application to the Moss-
American site. EPA has determined that the affected soil on the
site consists of approximately 50 percent fine material. But as
the FS acknowledges, "study of soil washing vendors in Europe
found [soil washing systems] have a practical upper limit for the
fraction of fines in the soil to be treated of 20 to
30 percent." Thus ... the soil-washing technology that EPA
proposes is not appropriate. (Kerr-McGee)
U.S. EPA's Response; The FS never implied that soil washing
alone could be effective at remediating all of the contaminated
soil on site. The proposed alternative includes bioslurry
treatment to address the fines fraction of contaminated soil.
COMMENT: The conceptual model of the slurry bioreactor (FS
Figure H-2) also neglects treatment of several ancillary process
flows. Oversize material is rejected from treatment, yet the
possibility exists that oversize materials may be heavily
contaminated. Wash water from the attrition scrubber has no
provision for treatment in the process schematic, yet if
scrubbing is successful the water will be contaminated. The
treatability study does not reflect the possible toxic effects of
surfactants from the scrubber on the subsequent slurry bioreactor
treatment. (Kerr-McGee)
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U.S. EPA's Response: The FS report indicated that oversize
material and reactor skimmings would be hauled offsite for
disposal in a special waste landfill. The ROD, however, states
that these materials are to be disposed of onsite in a RCRA-
compliant landfill. This decision was made to limit the actions
to the site boundaries.
The U.S. EPA recognizes that the treatability study data is
limited and proposes to conduct a pilot-scale treatability tests
to identify whether or not scrubbing will be beneficial or
deleterious to the removal of PAHs from soil. Pilot studies have
been reported wherein surfactant scrubbing was used prior to
biological treatment without toxic shock of the organisms. This
aspect of treatment feasibility would be evaluated in greater
detail in a pilot study.
COMMENT: The EPA guidance [Superfund LDR Guide No. 6A] for a
treatability variance to EPA's RCRA Land Disposal Restrictions
shows that the bioreactor must be designed for a 99.9 percent
reduction of certain PAHs, and must actually achieve 95 percent
reduction. EPA seems incorrectly to have assumed in the FS that
design for 95% reduction will suffice. (Kerr-McGee)
U.S. EPA's Response: The guidance cites that a 99.9 percent
reduction is required only if the threshold concentration for a
given restricted compound is exceeded. The guidance does not
state that the design must be based on maximum observed
concentrations. The FS assumes that the reduction required would
be based on what is fed to the reactor, as opposed to maximum
concentrations that have been observed onsite. Given that areas
of highly contaminated soil are interspersed with areas of lesser
contamination, the FS assumes that average concentrations of
restricted compounds in the feed material to the reactor would
not exceed threshold levels, and therefore a 95% design would be
sufficient.
Moreover, a treatability variance is required only when the LDR
treatment standard for a restricted constituent cannot be met.
The treatment standards for K001 PAHs are such that a
99.9 percent reduction in the maximum observed concentrations
would yield concentrations less than or approach the treatment
standard. Thus, achieving a 99.9 percent removal would likely
not require a treatability variance. The LDR ARAR can be met by
achieving the desired percentage reduction or reducing the
concentrations of the restricted constituents to 20 ppm.
Although general Superfund program goals are to achieve a
90 percent reduction in the primary contaminants of concern,
specific percentage reductions of carcinogenic PAHs are not
required to meet ARARs.
COMMENT: The soil treatment options are assessed based on the
assumption that the polynuclear aromatic (sic) hydrocarbon (PAHs)
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will migrate from soils into groundwater. At the same time, the
statement is made in the FS that these PAHs are not mobile, but
rather adsorb on soils. That fact is used as the basis for
concluding that burial of sediments in the existing stream
channel is appropriate. It is clearly inconsistent to include
that PAH compounds will not migrate and yet identify a preferred
remedy based on migration. Similarly, it is again inconsistent
to conclude PAHs will not migrate from a permeable stream channel
but will through less permeable site soils. (Chicago and
Northwestern Railroad)
U.S. EPA's Response: The FS acknowledges that PAHs are
relatively immobile when in a dissolved phase. The FS also
states that pure phase creosote could migrate at a faster rate
than dissolved phase, and is controlled by phenomena that are not
well understood. For these reasons, the FS suggests that removal
of the pure phase may be necessary to provide more assurance that
creosote will not migrate in concentrations that could yield
exceedances in water quality criteria. Soil treatment options
are predicated principally on the potential for exposure via
direct contact and ingestion of soil, and not solely on the
potential for creosote to act as a long-term source of
contaminants to groundwater. Groundwater extraction and
treatment may be required only for a period of time sufficient to
achieve state groundwater quality criteria.
COMMENT: The slurry biotreatment that EPA has proposed may prove
neither feasible nor effective and will certainly be far more
costly than EPA has estimated. A residence time of 150 days
would be more reasonable, would have an enormous impact, and the
treatment duration could be extended several decades or 10 times
as much equipment would be used. (Kerr-McGee)
U.S. EPA's Response; The basis for this concern appears to be
predicated on other concerns stated by Weston:
• That the slurry bioreactor has never been proven on a
full scale (Kerr-McGee);
• The treated effluent must be designed for more
stringent regulatory requirements than the FS assumed;
• The degradation rate was measured by CH2M HILL to be
slower than the FS assumed; and
• Numerous design needs have been overlooked including
scrubber-bioreactor interaction, wash water disposal,
and ancillary equipment. (Kerr-McGee)
The Weston comments suggest that, with application of proper
design objectives, the slurry bioreactor would have been screened
out of consideration based on implementability and effectiveness.
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While slurry bioreactor technology does not have as lengthy a
record of performance as some other remedial action technologies,
the statement that it has never been demonstrated on full scale
treatment of PAHs is incorrect. Slurry biotreatment is
considered an innovative technology because it has a limited
number of full-scale applications for treatment of hazardous
wastes, although it employs principles and equipment that have
been used in mining engineering and municipal waste water
treatment. Because U.S. EPA guidance for conducting remedial
investigations and feasibility studies and the NCP specify a
preference for consideration of innovative technologies in cases
where such technologies offer advantages (such as lower costs
for similar performance and fewer adverse impacts), the slurry
bioreactor was retained in the feasibility study for
consideration as a treatment option.
Treatability testing was performed for the purposes of assessing
whether or not the hazardous substances in soil and sediment at
the Moss-American site are amenable to biodegradation. These
tests were not intended, nor were they interpreted, as providing
a basis for design. Moreover, the use of this data as the basis
for design would be contrary to typical engineering practice in
the design of this type of facility. Instead, the U.S. EPA used
the results of the bench-scale testing to assess the relative
biodegradability of the hazardous substances of concern, and the
relative differences in degradation rates between slurry-type
treatment and land-type treatment.
The bench-scale treatability testing did provide information
indicating that the contaminants of concern are degradable, and
the degradation rates with land treatment are significantly
slower than the rates seen in slurry treatment. While the EPA
recognizes the potential for difficulties with implementing
innovative technologies, the NCP states a clear preference for
innovative technologies. U.S. EPA believes that results from
bench-scale testing is most encouraging.
Weston states that the "slurry bioreactor must be designed to
achieve significantly more complete degradation of certain PAHs
than EPA has recognized." The required reductions assumed in
the FS differ from that assumed by Weston who, in their
Table 8-1, assumed that the system would have to be designed to
achieve 99.9% reductions, apparently because some samples
exceeded the threshold values listed in the LDR guidance. The FS
assumes that the concentration in the feed to treatment will be
less than maximums since some mixing of lesser contaminated soil
with the highly-contaminated sediment and soil is expected to
occur. Therefore, the FS assumes that only a 95% reduction or
20 mg/kg in restricted (LDR) constituents would have to be
achieved.
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If a longer period of treatment is required, then costs to treat
will be higher. U.S. EPA, however, does not believe that the
costs could be 10 tiroes more than estimated in the FS, as
suggested by Weston. Costs for a doubling in the retention
period (to 30 days), for example, would be expected to result in
less than a doubling of reactor operating costs and less than a
doubling of equipment capital costs due to economies of scale in
operation of multiple units and due to assumptions regarding how
the equipment depreciates over time. There would be no increase
in other costs, such as materials handling of soil or sediment,
dewatering equipment, soil washing equipment, chemicals, etc.
In summary, the expected increase in the slurry bioreactor system
costs would be less than 100 percent for a doubling in the
required residence time. The U.S. EPA does not consider this
potential increase to be sufficient to warrant selection of an
alternative remedy at this time. Before the slurry bioreactor
technology would be implemented, pilot testing would be conducted
to develop the actual design criteria and refine the facility
costs.
COMMENT: EPA's assumption that a 15-day residence time in the
bioreactor will provide sufficient degradation is completely
unjustified. (Kerr-McGee)
U.S. EPA's Response; The treatability study indicated that, for
PAHs whose initial concentration was at least an order of
magnitude greater than the detection limit, these PAHs were
reduced by 83 to 95 percent within 7 days. Four PAHs were found
to have half-lives of 3 days or less. Although half-lives for
several of the carcinogenic PAHs and LDR-restricted compounds
were calculated to be greater than 15 days, the half-life
calculation (and first order reaction decay constant) were based
on concentrations observed throughout the 56 day incubation
period. Examination of Table K-4 indicates that nearly all of
the PAHs were reduced to concentrations approaching the detection
limit after the first 7 days of the 56 day incubation period, and
fluctuated around that concentration thereafter. Fluctuation
near the quantification limit may have lead to overestimation of
the half-lives (and underestimation of the first-order decay
constant) for several of these compounds. The half-life for
chrysene, for example, is reported to be 53 days even though the
concentration of chrysene was reduced by 75 percent in the first
7 days. Although measurements using soil did not have this
problem since initial concentrations were significantly higher,
the results of the sediment testing were promising and suggested
that similar results might be obtainable in the treatment of
soil.
The FS notes that "The kinetic models did not apply well to the
sediment flask data because the initial contaminant
concentrations were rapidly reduced to levels near or below the
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analytical detection limits. Degradation rates may also have
been inhibited by insufficient substrate to supply enough energy
for metabolic maintenance." (page K-6). Assuming similar
results can be obtained with soil as were observed in sediment,
the 15-day residence time does not appear unreasonable. To
reiterate, the data provided in the treatability test indicate
that biotreatment of sediments is promising, but such data is not
suitable for design. Pilot testing to verify these assumptions
is suggested in the FS and will also be included in the ROD.
12.3.2.6. Specific Comments Related to the Preferred Remedy
(Alternative 3A)
Comment: No effort will be made to provide a continuous vertical
hydraulic barrier and cap. This unsecured landfill will be
subject to groundwater inflow and surface recharge such that
further leaching and migration of contaminants could continue.
The landfill will be of detrimental value to the adjoining
subject property [property of A F Gallun & Sons] because of:
— Its potential to release groundwater and airborne
contaminants to the environment
— Visual incompatibility
— Negative social overtones
— It must rely on continued institutional controls
because of the remaining presence of carcinogens
U.S. EPA's Response: The proposed alternative for the Moss-
American site will reduce all site-related contamination in the
soil and sediment to the health based risk level of 1 x 10~4 or
less and treat the groundwater. So, while the treatment proposed
in the preferred alternative will not result in complete
destruction of all contaminants, residual risk at the site will
be below health based levels. The alternative also includes as
part of the groundwater treatment system, a cutoff wall that will
prevent off site migration of contaminants through groundwater
and a collection sump for the contaminated groundwater.
As far as physical appearance is concerned, the term "landfill"
is misleading. The area in which treated materials will be
redeposited will not be elevated, it will be covered and
revegetated and probably look very much like it does now.
Because the site lies within a county park, aesthetics are of
concern and will be addressed as part of the remedial design.
Issues related to health and safety during construction, e.g.,
control of airborne contaminants, will also be addressed more
fully during the remedial design. Airborne contaminants are only
of concern when the soil/sediment is disturbed, as it will be
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during the remedial action. Once the remedial action is
complete, airborne contaminants will not be a concern. U.S. EPA
is also concerned about reliance on institutional controls over
the long-term, which is one of the reasons a remedy was selected
that treats the highly contaminated soil/sediments and the
groundwater. The treatment minimizes the need for continued
institutional controls; the control measures will be reevaluated
every 5 years following implementation of the remedy and
discontinued when they are no longer necessary.
COMMENTS: Several residents of the area felt they should have
been notified of the proposed remediation and others expressed
concerns about aspects of the proposed alternative. These
concerns included rechanneling the river as opposed to
maintaining the old channel, impact on business and residences,
and impact on the park corridor. All residents who commented
wanted the site cleaned up.
U.S. EPA/s Response; Many of the concerns have been addressed in
the previous portions of the Responsiveness Summary. Public
notification of the on-going RI/FS included Fact Sheets and
newspaper notification. The proposed plan also involved mailings
and notification. In addition, the Milwaukee newspapers carried
several articles about the site and site activities. U.S. EPA
extended the public comment period to allow for as much comment
as possible.
The agency has noted the concerns of residents and is doing as
much as possible to limit impact on the river corridor and
surrounding area. Work on the site will be limited by necessity
to the warmer months of the year. The work will proceed one
segment at a time, from the far north end to the confluence with
the Menomonee River. During the time that work is in progress,
the segment currently undergoing construction will not be open to
the public for a period of a few months. No bridges or streets
will be closed. There will probably be less disruption to the
surrounding area than if road repair or construction were in
progress, as work will be limited to the river area itself.
Environmental concerns were discussed in greater detail
previously. An ecological assessment is now in progress that
will assist us in limiting impact as much as possible.
Construction work will proceed around large trees and wetland
areas as much as possible.
COMMENT: Several residents wanted to go on record as being
opposed to incineration as an alternative and to express their
dismay that incinerator vendors were attempting to pass
themselves off as residents in favor of incineration.
U.S. EPA's Response; Acknowledged.
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COMMENT: Steven Skcavronek representing the Technical Advisory
Committee of the Milwaukee Estuaries Remedial Action Plan
explained the cleanup plan for the Milwaukee harbor and the three
major rivers that empty into it. He expressed concerns with the
planning process rather than the preferred alternative; the fact
that cleanup levels at the site were human health based rather
than environmentally based; that the cleanup did not include the
Menomonee River as well as the Little Menomonee; and "lack of
coordination" with the Great Lakes National Program (GLNPO)
office as well as the Water Division (WD).
U.S. EPA's Response; U.S. EPA looks forward to working with the
RAP group in the upcoming cleanup at the Moss-American site. In
respondence to your concerns, the cleanup levels are human health
based because there are no comparable numbers available for the
environment. U.S. EPA and the State of Wisconsin believe that
the cleanup level proposed is equally protective of the
environment. The Menomonee River was not included as part of
the site because background samples taken upstream in the
Menomonee River and those taken below the confluence of the
Little Menomonee River and the Menomonee River (downstream) have
similar PAH levels. There is no present evidence to indicate
that the site has contributed to the contamination already
present in the river. All activities involving the Moss-American
site have been coordinated with GLNPO and WD as well as many
other offices. The WD has commented on the RI, the FS, and
approved the proposed plan for remedial action at the site.
COMMENT: Several residents expressed appreciation and support
for the remedial action.
U.S. EPA's Response: Acknowledged.
COMMENT: The County of Milwaukee is concerned about the quality
of the data.
U.S. EPA's Response: Data generated by U.S. EPA and its
representatives at this site has been subject to strict quality
assurance/quality control procedures.
COMMENT: The County of Milwaukee expresses concerns regarding
the possible location of" previous dredge materials at the site.
U.S. EPA's Response; U.S. EPA will sample for existing
contamination before determining the route of the river.
COMMENT: The County of Milwaukee raises the possibility of other
alleged ARARs, mentioning the public interest in streams in
Wisconsin, riparian rights, permitting requirements, and
legislative approval.
U.S. EPA's Response: The legal issues, including riparian rights
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are being investigated and will be addressed as appropriate and
required by Federal law. Please note, however, that the Agency
does not believe the issues raised will influence the selection
of a remedial action at the site. Only promulgated State
standards, requirements, criteria, or limitation under a State
environmental or facility siting law, and only those identified
by the State in a timely manner, are ARARs. Moreover, consistent
with Section 121(d) of CERCLA, no Federal, State, or local permit
shall be required for the portion of any remedial action
conducted on-site. In any case, the Wisconsin statute requiring
a permit for changing of stream courses does not apply to
municipal or county-owned lands in counties having a population
of 750,000 or more. Furthermore, U.S. EPA has obtained the
consent of the State of Wisconsin to the selected remedy.
COMMENT: The County of Milwaukee suggests that it may seek
compensation for the affect of the new river upon its riparian
rights.
U.S. EPA's Response: U.S. EPA is acting pursuant to its powers
in rerouting the river, and is increasing the value of the
County's property by replacing a contaminated channel with a new
channel. The question of liability or compensation is not
relevant to the issue of selection of remedy.
COMMENT: The County of Milwaukee favors a delay in selection of
a remedy pending review of wetland related procedures.
U.S. EPA's Response: U.S. EPA is complying with substantive
State and Federal wetland related ARARs. Pursuant to Section
121(e) of CERCLA, 42 U.S.C. Section 9621(e), U.S. EPA is not
required to obtain permits at the site.
COMMENT: The County of Milwaukee incorporates the comments
prepared by Roy. F. Weston for Kerr-McGee.
U.S. EPA's Response; These comments have been addressed above.
COMMENT: Kerr-McGee argues that it is not a PRP.
U.S. EPA's Response: The question of liability is not relevant
to the issue of selection of remedy.
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12.3.2.7. Comments Received from the Wisconsin Department of
Natural Resources:
U.S. EPA received a letter from the WDNR dated July 25, 1990
concerning issues related to the selection of remedy at the Moss-
American site. During the development of this ROD, U.S EPA has
strived to address and resolve the issues identified by the State
of Wisconsin. U.S. EPA has worked closely with the State and
believes it has resolved the outstanding issues as reflected in
the ROD. U.S. EPA appreciates the cooperation displayed by the
State of Wisconsin in coming to terms on a number of complex and
difficult issues. A letter of concurrence has been received from
WDNR.
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