United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R05-91/172
September 1991
SEPA
Superfund
Record of Decision
Motor Wheel, Ml
-------
50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R05-91/172
3. Recipient^ Acceaalon No.
TKMandSubfltl*
'UPERFUND RECORD OF DECISION
Motor Wheel, MI
First Remedial Action - Final
5. Report Date
09/30/91
7. Authof(i)
0. Performing Organization Rept No.
8. Performing Orgalnlzaflon Nam* and AddiM*
Pro|*ct/Taak/Work Unit No.
11. ContracqC) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Nun* and Addr***
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/000
14.
15. Supplementary Note*
16. Ab*tr*ct(Umlt: 200 word*)
The 24-acre Motor Wheel site is an inactive industrial waste disposal site in
Lansing, Ingham County, Michigan. Land use in the area is predominantly industrial.
The site overlies a glacial till and a glacial aquifer. From 1938 to 1978, the Motor
Wheel Corporation used the site for the disposal of solid and liquid industrial
wastes including paints, solvents, liquid acids and caustics, and sludge. Wastes
were disposed of in tanks, barrels, seepage ponds, and open fill operations. An
estimated 210,000 cubic yards of waste fill is in place onsite. As a result of
disposal practices, contaminants have leached through the soil and into the
underlying glacial aquifer and perched zone. Between 1970 and 1982, at least three
onsite clean-up actions were initiated. In 1970, the State required the removal and
offsite disposal of solid wastes, paint sludge, and oils from seepage ponds and
backfilling of excavated pond areas. In 1978, industrial wastes and degraded soil
were excavated and stockpiled onsite under a clay cover. In 1982, the site owners
removed three 10,000-gallon tanks, their contents, and surrounding contaminated soil,
along with contaminated fill material containing an unknown quantity of drums. This
Record of Decision (ROD) addresses the waste mass and ground water contamination in
(See Attached Page)
17. Document Analytic a. Descriptor*
Record of Decision - Motor Wheel, MI
First Remedial Action - Final
Contaminated Media: soil, debris, gw
Key Contaminants: VOCs (benzene, PCE, TCE, toluene, xylenes), organics (PAHs, PCBs,
pesticides), metals (arsenic, chromium, lead)
b. ktentiflers/Open-Ended Term
e. COSATI Reid/Group
Availability Statement
19. Security Claw (Thl* Report)
None
20. Security CU** (Thi* Page)
None
21. No. of Page*
60
22. Price
(See ANSI-Z39.18)
SM Instruction* on Rannt
(Formerly NTIS-3S)
Department of Commerce
-------
EPA/ROD/R05-91/172
Motor Wheel, MI
First Remedial Action - Final
f
.^ostract (Continued)
the perched zone and the glacial aquifer. The primary contaminants of concern affecting
the soil, debris, and ground water are VOCs including benzene, PCE, TCE, toluene, and
xylenes; organics including PAHs, PCBs, and pesticides; and metals including arsenic,
chromium, and lead.
The selected remedial action for this site includes backfilling the northern portion of
the fill area with 125,000 cubic yards of fill; capping the disposal area with a
14.9-acre multi-media cap; installing a slurry wall at the western and southern boundary
of the disposal area; installing ground water recovery wells or trenches downgradient,
and a collection transfer system to deliver water to an onsite treatment facility;
pretreating ground water onsite to remove iron and manganese using aeration,
clarification, and filtration if needed, followed by onsite treatment using air
stripping and carbon adsorption; using activated alumina to remove fluoride from ground
water, followed by offsite discharge of the treated water to a publicly owned treatment
works (POTW); monitoring ground water; and implementing institutional controls including
deed and ground water use restrictions, and site access restrictions such as fencing.
The estimated present worth cost for this remedial action is $30,720,300, which includes
a capital cost of $11,083,300 and an annual O&M cost of $1,277,400 for 30 years.
PERFORMANCE STANDARDS OR GOALS: Ground water clean-up goals are based on State
health-based standards or method detection limits (MDL), whichever is higher.
Chemical-specific goals include benzene 1 ug/1 (State), PCE 1 ug/1 (MDL), TCE 3 ug/1
(State), toluene 800 ug/1 (State), xylenes 300 ug/1 (State), and lead 5 ug/1 (State).
-------
DECLARATION FOR THE RECORD OF DECISION
Site Name and Location
Motor Wheel Disposal Site
Lansing, Michigan
Statement of Basis and Purpose
This decision document represents the selected remedial action for
the Motor Wheel Disposal site, Lansing, Michigan, which was chosen
in accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA) and, to
the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP).
This decision is based upon the contents of the administrative
record for the Motor Wheel Disposal site.
The State of Michigan concurs with the selected remedy.
Assessment of the Site
Actual or threatened releases of hazardous substances from the
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 Remedy
This operable unit addresses remediation of ground water and source
control by reducing the potential for continuing ground water
contamination from the on-site waste mass and reducing the threat
from contaminated ground water through treatment.
The major elements of the selected remedy include:
* Installation of an approximately 11.3 acre Michigan Act 64
cap over the disposal area;
* Back-filling to cover exposed fill areas and to establish
an acceptable slope in the excavated area of the site for
extension of the cap;
* Extraction of contaminated ground water from the perched
zone and the glacial aquifer and treatment of the ground water
by air stripping, granular activated carbon, and alumina
-------
reaction on-site and treatment of the off gases;
* Site deed restrictions to limit development and land use
and to prevent installation of drinking water wells or other
intrusive activity at the site; and
* Ground water monitoring to assess the state of the
remediation.
* A slurry wall will be installed to facilitate the
dewatering of the perched zone aquifer.
Statutory Determinations
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable and satisfies the
statutory preference for remedies that employ treatment that
reduces toxicity, mobility, or volume as a principal element. As
this remedy will result in containment of waste on-site and
initially result in hazardous substances remaining on-site above
health-based levels during the remediation of ground water, a
review will be conducted within five years after commencement of
remedial action to ensure that the remedy continues to provide
adequate protection of human health and the environment.
Date
'Regional7Administrator
U.S. EPA - Region V
-------
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
MOTOR WHEEL DISPOSAL SITE
LANSING, MICHIGAN
I. SITE NAME. LOCATION AND DESCRIPTION
Motor Wheel is a 24 acre site located on the northeast edge of the
City of Lansing within the NE k, SV \, Section 3 of Lansing
Township (T.4N.,R.2W.), Ingham County, Michigan (Figure 1). The
site is bordered by abandoned Michigan Central Railroad tracks to
the west and north, by the W.R. Grace & Co. plant (formerly
Michigan Fertilizer Company) to the south, and by the Lansing/
Lansing Township boundary to the east. The Granger/North Lansing
Sanitary Landfill is located to the northeast of the site, Paulson
Street Landfill (currently a park) is located to the north, the
Friedland Iron and Metal Company lies to the northwest, and the
North Lansing Fill No. 2 Board of Water and Light is located to the
southwest. Figure 2 shows the bordering properties and the current
land usage near Motor Wheel. No use of perched zone or glacial
aquifer ground water has been identified in the vicinity of the
site.
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES
The property was used by Motor Wheel Corporation as a disposal site
for industrial wastes from 1938 until about 1978. The types of
disposed wastes included, solid and liquid industrial wastes,
including paints, solvents, liquid acids and caustics, sludges and
other wastes. Wastes were disposed of on the property in tanks,
barrels, seepage ponds and open fill operations.
Between 1964 and 1986 Motor Wheel Corporation was a wholly owned
subsidiary of Goodyear Tire and Rubber Company. Because of this
ownership, Goodyear Tire and Rubber Company is associated with the
site and is a respondent to the Motor Wheel Consent Order.
Between 1970 and 1982 at least three cleanup actions were initiated
which resulted in the excavation of and off-site disposal of waste
materials. In 1970 the Michigan Department of Natural Resources
(MDNR) requested that the Motor Wheel Corporation remove solid
wastes, paint sludges, and oils from seepage pond areas for
disposal off-site. Some of the excavated materials were disposed
of off-site and the former pond areas were backfilled.
In 1978, following acquisition of the property by MSV Associates,
while stripping overburden from the on-site sand and gravel
deposits, industrial wastes and degraded soils were exposed. The
exposed materials were excavated, stockpiled on the western part of
the site and covered with clay.
In December of 1982 there was a removal of three 10,000 gallon
tanks and their contents, and degraded fill material from several
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c
)
Area of Investigation
Motor Wheel Disposal Site
T.4N., R.2W.
Lansing Township
Ingham County
Lansing, Michigan
FIGURE!
City of
Lansing
Area of
Investigation
ngham
County
BRAVING SUPPLIED BYi HUNTER/KECK INC.
GRAVM
JDG
4/24/90
RCV:SC>
4-l>w_ / 0
-------
t
Shecidon Rood
FIGURE2
Clin'0" Coun'r
Doggett's
Cot/My
Granger North Lansing
Sanitary Landfill
Paulson St.
j
Paulson
Street
Landfill
Friedland Iron
a Metal
Company
Motor Wheel
Disposal Site
W.R. Grace
a Company
f « 750' (approximately)
Drawing supplied by: HUNTER /KECK INC.
North Lansing Fill No. 2
Board of Water a Light
Oovid St.'
Adjacent Land Use Sketch
Motor Wheel Disposal Site
Section 3, T.4N..R.2W.,
Lansing Township,
Ingham County, Michigan
[ORAVM
CDH
em C»UU.TV« on OCVCUM
4/35/90
RCVlSCfr
NUMlC*
3144-002
icv
-------
locations on the site. The three tanks and approximately 800 cubic
yards of contaminated soil and fill surrounding them, and
approximately 350 cubic yards of fill material containing an
unknown number of drums were disposed of off site.
All operations at the site were discontinued in 1987. The entire
site is currently inactive.
MSV Associates, which purchased the site in 1978 and mined sand and
gravel in the northeast portion of the property until 1987, is the
current owner of the property.
The key surface feature of the site, the sand and gravel pit
extending over the northern portion of the site, is the result of
earlier quarrying activities. The pit area, excavated to a depth
of 50 feet, has relatively steep sided walls and a slope ranging
from 2:1 (horizontal:vertical) to near vertical. There are several
small ponds in the eastern part of the pit bottom. The remainder
of the site has been covered with fill from stripping and gravel
washing operations.
The unmined portion of the site is relatively flat, with occasional
abrupt changes in topography resulting from the filling operations
that took place during overburden stripping. Vegetation on the
unmined portion of the site consists mainly of small trees, brush,
and dense indiscriminate ground cover growth. The site contains no
structures.
The site was placed on the National Priorities List (NPL) on
October 4, 1986 (50 FR 41015). On June 26, 1987 Motor Wheel
Corporation, W.R. Grace & Co., and Goodyear Tire and Rubber Company
signed an Administrative Order by Consent agreeing to conduct a
Remedial Investigation (RI) and Feasibility Study (FS) at the Motor
Wheel site.
III. COMMUNITY RELATIONS HISTORY
An RI kick-off meeting was held June 16, 1988. At the meeting the
U.S. EPA and MDNR discussed the activities which would take place
during the RI. The RI Report for the Motor Wheel site was released
to the public on May 15, 1990. A public meeting was held May 22,
1991 at which U.S. EPA and MDNR discussed the findings of the RI.
The FS and the Proposed Plan were released July 18, 1991. A fact
sheet summarizing the Proposed Plan and remedial alternatives was
released to the public at that time. These documents and other
supporting documents were made available to the public in the
administrative record maintained in the U. S. EPA Docket Room in
Region 5 and the information repository at the Lansing Public
Library in Lansing, Michigan. The notice of availability for the
RI/FS Report and the Proposed Plan was published in the Lansing
Journal on July 17, 1991. A thirty day public comment period was
-------
held from July 18, 1991 through August 19, 1991. In addition, a
public meeting was held on July 24, 1991. At this meeting,
representatives of the U.S. EPA and NDNR answered questions about
problems at the site, the remedial alternatives under
consideration, and accepted formal comments from the Public
regarding the proposed alternative and other alternatives analyzed
in the FS. A response to these comments and to written comments
received during the comment period is included in the
Responsiveness Summary, which is part of this Record of Decision.
No request for an extension of the public comment period was
received and the public comment period ended August 19, 1991.
This decision document presents the selected remedial action for
the Motor Wheel site, in Lansing, Michigan, chosen in accordance
with CERCLA, as amended by SARA and, to the extent practicable, the
National Contingency Plan. The decision for the selected remedial
action is based on the administrative record.
IV. SCOPE AND ROLE OF OPERABLE UNIT WITHIN BITE STRATEGY
This ROD addresses remedies for the waste mass and the ground water
contamination in the perched zone and the glacial aquifer at the
Motor Wheel site. The waste mass represents a principal threat as
a source for contamination of ground water in the perched zone and
the glacial aquifer. The ground water represents a primary threat
to human health and the environment due to ingestion of and contact
with water from the contaminated portions of the perched zone and
the glacial aquifer that contains contaminants at concentrations
above the Maximum Contaminant Levels (MCLs) established by the Safe
Drinking Water Act and/or Michigan Act 307 standards.
U.S. EPA and MDNR will evaluate risks posed by the Motor Wheel site
to the Saginaw bedrock aquifer in a second operable unit. The
signatories to .the 1987 Administrative Order by Consent are
currently conducting an investigation to evaluate the impact of the
site on the Saginaw aquifer which is the source for the Lansing
public water supply. The signatories have agreed to install
monitoring wells to determine water quality in the Saginaw aquifer
below the site and to evaluate the integrity of the shale unit of
the Saginaw which may act as an aquitard between the glacial
aquifer and the bedrock. These data will be used to determine the
need for remediation of the bedrock aquifer through a subsequent
operable unit.
V. SUMMARY OP SITE CHARACTERISTICS
Site Geology and Hydrology
The Motor Wheel site lies in level to gently rolling topography
produced by depositional processes associated with the continental
glaciation during the Pleistocene epoch. The glacial deposits rest
unconformably on the Pennsylvanian sediments of the Grand River and
-------
Saginaw formations. The Grand River and Saginaw formations are the
uppermost members in the Michigan Basin.
The Grand River formation is composed principally of sandstone and
red and black shale. The formation occurs mainly as remnants in
surface structures of the Saginaw. The Grand River formation is
known to be present approximately one mile north of the site where
it is 125 feet thick in some areas but is not present beneath the
Motor Wheel site.
The Saginaw, in places more than 300 feet thick, underlies most of
the Lansing area. It is composed mainly of sandstone and shale
with thin beds of coal and limestone of limited lateral extent.
Immediately below the Motor Wheel site the Saginaw consists of
alternating stream channel sands, river flood plain silts and
clays, shallow water marine or tidal swamp shales and limestones,
and coal seams. Thickness of this complex varies in the region,
but is projected to be approximately 450 feet thick in the vicinity
of the site. Regionally, the top of the Saginaw dips northward and
may consist of sandstone, shale, coal or limestone, with sandstone
and shale being most common.
Where present the thickness of the shale across the area varies
between 4 feet and more than 140 feet. The shale layer appears to
have extreme undulation of the top and bottom surfaces, and
demonstrates dramatic changes in thickness over short distances.
The Motor Wheel site is located on the western flank of the Mason
esker. The glacial deposits range between clay, silt, sand, and
gravel, and include various mixtures of these size fractions. The
predominant sediments and their generic classification are: clay
and silt (lacustrine); silty-clay and sandy-clay containing
pebbles, cobbles, and boulders (till); and stratified, fine to
medium, buff-tan sands containing beds of gravel (esker). The
sediments are quite variable laterally. The site is beyond the
floodplain of the Grand River. No wetlands have been identified at
the site. '
An upper till unit, ranging in thickness from 10 to 45 feet,
underlies most of the site south and west of the excavated area.
The till generally thickens to the southwest however, in one area
the till is absent and the waste and soil fill rest directly on
clayey sand and gravel. The Mason esker sand and gravel underlies
till or lacustrine clay beneath the entire site, with the exception
of the excavated area.
The Saginaw formation contains an aquifer which is the principal
source of water for the region. This generally confined aquifer is
recharged mainly in places where it is directly overlain by glacial
aquifers. Wherever the Saginaw shale, a Quaternary clay, or
glacial till occurs on the top of the Saginaw sandstone, the local
recharge is limited or non-existent.
-------
Transmissivities of the Saginaw aquifer in the Lansing area, as
shown in the RI/FS, range from 535 square feet per day (ft2/d) to
10,628 ft2/d with the average value 3128 ft2/d. Storage
coefficients range from 2.5X10~5to 4.3X10~3with the average value
of 3.8X10"4.
At the Motor Wheel site and vicinity there are two water bearing
zones in the glacial deposits. There is a perched zone and an
unconfined aquifer in the sediments of the Mason esker.
The perched zone, although limited in the northeast portion of the
site and interrupted by a local discontinuity in the south central
part of the site, appears to be continuous over the site to the
south and west (Figure 3). The vertical hydraulic conductivity of
the perching bed ranges from 3.2X10~8centimeters/second (cm/s) to
1.0X10~7cm/s. The direction of ground water flow in the perched
zone under the site is controlled by the excavated area which
intercepts the perching layer. A ground water divide is present in
the southwest part of the site. North of this divide ground water
flow is to the northeast toward the excavation. South of the
divide the flow direction is toward the southwest, which is the
direction of regional flow in the glacial aquifer (Figure 4). This
interpretation of flow direction is confirmed by the presence of
intermittent seeps in the south and west walls of the excavation at
the approximate elevation of the perching clay.
Ground water in the glacial aquifer flows toward the south-
southwest across the site. The average horizontal hydraulic
gradient across the site is 0.001 (Figure 5). There is variation
in the central part of the site because of the influence of the
excavated area. Vertical gradients across the site vary from 0.037
to 0.035. The glacial aquifer is recharged from the perched zone
and through the bottom of the gravel pit where it intercepts the
water table.
Mature and Extent of Contamination
Waste Mass and Soil
A significant waste fill mass has been identified in the non-mined
portion of the site (Figure 6). The waste fill is in the upper
glacial drift in a mass up to 25 feet thick covering nearly 10
acres, and is covered by a layer of silty-clay soil derived at
least in part as a byproduct of the sand and gravel washing
operation.
An estimated 210,000 cubic yards of waste fill is in place at the
site. Materials identified in the fill matrix are soils, railroad
ties, tires, vesicular and glassy slag, demolition debris, asphalt,
plastic, and glass fragments. Along with the solid wastes, liquid
wastes are known to have been disposed of on the site. The upper
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FIGURE3
Perched Zone Extent
Motor Wheel Disposal Site
Lansing, Michigan
• S«ep
• Monitor Well
^ Soil Boring
S8-J4.A.
MW-II Y
Extent of parched Aquifer
.. •
• '•' • '•' • '•'. • '• '• •'•'• '•**''* '
123 150 fMt
ORAVNi
COM
DAlt' 4/25/90
PSJJLtl
NUHlCRt
3H4-002J 0
-------
FIGURE A
Perched Zone, Water Level
Contours; Dec. 8, 1989
Motor Wheel Disposal Site
Lansing, Michigan
WW-20
ww-il
• Monitor Wall
© Staff Gauge
Contour Interval: V
Datum in f««t relative
to N.C.V.D.
UW-12S
• 864. J1
BRAVH, EDH
RCVlSCDi .. 13144-003
-------
FIGURE 5
Glacial Aquifer
Watei—Table Contours
Dec. 8, 1989
Motor Wheel Disposal Site
Lansing, Michigan
• Monitor Well
• Staff Gouge
Contour Interval: .2*
Datum in fe«t relative
to N.C.V.O.
S14.0J
UW-12S
UW-120
813.86
(Ml
DRAWN.
EDH
' 4/25/90
Revise*
3i«4-ooalo
-------
FIGURE 6
Approximate Area
Waste Disposal
of
uw-20
Motor Wheel Disposal Site
Lansing, Michigan
UW-19
Monitor Well
Limit of Waste Fill
ea of Waste
' X X X X X X/
Disposal^1
MW-13S
MW-1
N
>2S 250 f««t
a
eatrxnic «n
DRAWN. £DH (BATE. 12/19/90
RCVKEB-
3144-002
-------
12
portions of the waste mass are unsaturated. The lower portion is
saturated with leachate produced by infiltration from the surface
due to the proximity of the perching layer. Analyses of waste mass
material and soil are summarized in Tables 1, 2, 3, 4, and 5.
Saturated waste fill material and soils at depths greater than 4
feet contain significant levels of 1,2-dichloroethane,
trichloroethene, toluene, ethylbenezene, and xylenes. Pesticides
and PCBs are present sporadically across the site. Semivolatile
compounds are present in soils in the waste mass area at depths
generally greater than 10 feet and sporadically in the interval
shallower than 10 feet.
Ground Water
Results from analysis of ground water from the perched zone are
summarized in Table 6. 1,2-dichloroethene and bis(2-ethylhexyl)
phthalate were commonly detected in concentrations ranging from 26
ppb to 330 ppb and from 11.1 ppb to 19.5 ppb respectively.
Secondary water quality standards for nitrate, chloride, fluoride,
and sulfate are exceeded in samples from several of the perched
zone and glacial aquifer wells.
Results of analysis of ground water from the glacial aquifer are
summarized in Table 7. Detections of trichloroethene, vinyl
chloride, 1,2-dichloroethene, and benzene are centered in the south
central part of the site.
The primary route of movement of contaminants detected on-site is
with the ground water. Constituents have been identified in the
glacial aquifer and extending off the site generally in a south-
southwest direction. Infiltration of precipitation through the
unsaturated zone to the waste mass forms leachate which has
migrated into the glacial aquifer even though the rate of migration
may be somewhat -reduced by the presence of the perching clay in
some locations. The potential also exists for contaminants in the
perched zone ground water to move laterally as evidenced by the
presence of seeps along the south and west walls of the sand and
gravel pit.
VI. SUMMARY Of SITE RISKS
During the course of an RI/FS the U.S. EPA requires that a risk
assessment be prepared according to U.S. EPA policy and guidelines.
At Motor Wheel, PRP contractors prepared a risk assessment under
the 1988 Administrative Order for the RI and FS. This risk
assessment provides U.S. EPA with a basis for selection of a remedy
which would be protective of public health, welfare, and the
environment. The risk assessment, prepared by the PRP contractor,
utilizing available information is consistent with the U.S. EPA
policy and guidance. It provides an estimate of the health or
environmental problems that could result if the waste mass,
contaminated soil and sediments and the contaminated ground water
-------
TAPLF 1
Summary of Metals Analysis In Soils at MWOS
SORPACS SEDIMENT SAHPLES MC/KC (ppa) DRY WT .
L- J
L- 4
L- S
DASH (-
Location
::::::=:
SB- 1
CD 9 A
50-24
SB-26
DASH (-
Location
:::::=::
SB- 7
SB- 9
SB-19
SB-23
C& 9H
30 fcw
en n
30-3 J
DASH ( -
Location
::sss:rs
SB-IS
SB-19
SB-21
SB-23
en_i «
3O— J I
en. H
• 30-J«J
Surf.
Surf.
Surf. 14.2
-) indicates analysis
Depth Sb As
:::::::: ::::::=:::::
0'-2-
0--2"
-) indicates analysis
Depth Sb As
:;:::::: ::::s:s=s:ss
2 '-4- — 4«.2
2'-4'
2'-4'
2'-4'
-) indicates analysis
Depth Sb As
r:::::ss :ss:::r==s=:
4'-6'
• -e •
•-10' -- 33.6
-.10'
* a*
"
— ^
3.8
was
SOIL
Be
-----
..
—
was
SOIL
Be
sssss
..
..
"
"
was
SOIL
Be
-----
•..
--
*9.t
«
122.0 171.9 BS.B
36.3
190.5 254.6 118.4 0.15 71.5
below the selected cut-off value listed
BORIHC SAHPLES 0'-2' HG/KC (PP«) DRY
Cd Cr Cu Pb He Nt
:::::::::::::«::=:=: ::s:::::s::::ssss:::
99.7 92.0 125.6 0.45
57.2 — 0.16
below the selected cut-off value listed
BORIHC SAMPLES 2'-4' (1C /KG (ppei) DRY
Cd Cr Cu Pb He HI
:::::zx::::s:::93s:::::r=:s:3:::ss::::rz
64.5 70. 8 0.22
194.6 302.5 ?20.1 0.28 90.1
215.0 228.0 299.3 0.20 50.0
*- 132.1 173.0 144.7 0.21 66.6
below the selected cut-off value listed
BODING SAHPUS 4' -10" nG/XG (pp«) DBT
Cd Cr Cu Pb He Hi
s:s:st:sssssssssssisstssissssiiissii::i:
9.1 130.0 150.0 294.0 0.50
164.0 308.0 107.9 — 92.0
153.0 528.0 4090.0 — 157.0
106.3 197.1 141.6 0.65 54.7
0.3 1.9
0.5 3.8
froe Table 4
WT.
Se AC
s:srsiss:::s
0.9 —
0.3 1.0
froe, Table 4
WT.
Se AC
IISTSSSSSSS:
1.0
0.6 4.1
0.7
fro* Table 4
WT.
Se AC
ss:s::::::x:
0.4
0.4
--
0.6
0.2 1087 S
203.7
. 1
Tl Zn :
isi::i:s::::::-
244 T :
01
.1 ~ •
03 U< S .
.1
Tl Zn
::::::::::::::
66.0
106 1
214 0
01 A \& f
. J * J3 . C
.1
Tl Zn
SSSSSSSZSSSS5£
447.0
2iT :
:£9.c .
01
.1 * "
o.i :l4 :
Ot
.1 • •
o.i
DASH (--) indicates analysts was below the selected cut-off value listed froei Table 4.1
SOIL BORIHC SAUPLtS > 10' HC/KC (pjm) DRY WT.
Location
SB- 1
SB- 2
SB- 2
SB- 6
SB- 6
SB- 9
SB- 9
SB-IS
5B-ZZ
SB-26
58-29
5B-Z9
SB-30
SB-32
Depth
13--19'
16--18"
22'-2«'
lf-13'
13--1S'
9--12'
16'-18-
10'-12"
10'-12'
10'-12'
-«4
20 '-22-
14--16"
Sb
7.1
14.0
8n
--
"
"
Aa
41.5
59.6
141.0
"
--
"
Be
—
—
--
—
Cd
19.3
1.7
5.2
39.3
5.0
—
--
-•
Cr Cu Pb
-- 1125. T 5019.1
427.0 360.4 206.7
169.7 144.7 92.2
53.4 48.3
397.1 547.0 180.1
316.7 508.9 572.0
366.7 1038.7 495.6
— 175.0 113.0
139.9 1538.9 403.0
— 226.8
90.8 443.3
263.2 484.9
Hf Hi
0.6
— 73.4
0.5 173 8
0.6 106.4
2.1 146.1
0.2
1.1 85.2
0.3
--
Se
1.7
1.7
0.6
1.1
1.4
23.6
0.8
A<
—
4.4
2.3
1.1
2.0
--
2.0
Tl
0.2
0.1
o :
f; . \
Zr.
::oi .-
: :o «
62. e
t i ^ •
i-:oo :
P53 •.
284. 0
-.89 8
24: i
'.: i
*1f
08
oo
15
DASH (--) Indicates analysts was below the selected cut-off v«lu« listed Jro« T«bl« 4.1
-------
TABLE 2
Summary of Pesticides and PCS Analysis in Soils at MWDS
SORFACl SEDIMENT SAflPLES Hlcrocr«na/KG (ppb) DRY WT.
Location
------=-
L- 1
L- 2
L- 3
L- 4
L- 5
Depth
szzszzzss
Surf.
Surf.
Surf.
Surf.
Surf.
PCB-
1254
zzzz:
0
0
o
0
0
PCB-
1260
--------
0
0
0
u
0
4,4'- 4.4'
COD DDE
z:zz::=z::
0 0
0 3.
0 0
31.93 0
0 0
- 4.4'-
DDT
--------
0
10 2.43
0
39.06
0
ALDRIN
zzzszsz
116.04
0
12.19
216.35
0
DIEL-
DRIN
:z:z::z.
520.31
0
129.22
737.14
15.66
ENDRIN
••-f-"-
0
0
0
0
0
ENDOSOLFAN
SULFATS
szzszssszzzz
0
0
0
0
0
HEPTA-
CHLOR
z::zzsz
5.07
0
0
59.04
0
LIN-
DANE
:::«:=:::
0
0
0
u
u
0 : Below detection Halt
SOILS 0'-2' HicrotT«»a/KG (.ppb) DRT WT.
Location
--------
SB- 1
SB-26
Depth
zssszzzsz
0'-2'
0--2"
PCB-
1254
Z33SZ3
0
0
PCB-
1260
----=-
0
0
4.4'- 4.4'-
DDO ODE
zsszzsszzzzzz
0 0
26.78 71.54
4,4'-
DDT
-=----
a
50.14
ALDRIN
------
a
0
DIEL-
DRIN
-------
6.38
60.16
ENDRIN
--------
0
0
ENDOSOLFAN
SOLFATE
zssrzzsszziz
0
0
HEPTA-
CHLOR
--------
0
0
LIN-
DANE
s:z::::=
0
0
0 s Below detection li«it
SOILS 2'-4' Hlcrt>crau/KC (ppb) DRY WT.
Location
SB- 7
SB- 9
SB- 19
SB-23
S8-30
SB-33
Depth
2'.
2'-
2 •
2'-
2'-
2'-
PCB-
12S4
402.
172.
0
0
0
0
PCB-
1260
8 0
S 0
193.2
0
0
0
4.4'- 4.4'
ODD DDE
0 0
0 0
0 0
0 0
0 0
0 0
- 4.4'-
DDT
0
0
0
0
0
0
ALDRIN
0
0.
0
0
0
0
DIEL-
DRIN
0
21.4
0
0
1563.65
0.85
EHDRIN
0
0
0
0
0
0
ENDOSOLFAN
SOLFATE
319.0
0
0
0
0
0
HEPTA-
CHLOR
0
0
31.2
53.4
0
0
LIN-
DANE
0
0
0
0
n
0
0 * Below detection liait
SOILS 4--10' Hierecr«M/XG (ppb) DRY WT.
Location
SS3SS333
SB-IS
SB-18
SB-19
SB-25
SB-28
SB-31
58-32
SB-33
D<
sss:
4
6
8
ipth
ssss:
r-«
-10
'-8
'-8
-10
'-8
•-8
•-«
is
PCS- PCS- 4.4'- 4.4'- 4.4*- DIEL- CNDOSOLFAN HIFTA- LIN-
1254 1260 ODD DDE DDT ALDRIN DBIM SNDRIN SOLFATI CHLOR DANE
3S33C3S3s>s:s3S3Ssc:sssS3ssz33:3: = s:3S33a3933z:3S33::33ss = 3S33Z3:333:ss::x:s::::
0 . 0 378.0 277.0 0000 000
0 4ST.7 000000 0 0 0
0 104.9 000000 0 0 0
0 0 0 0.6 2.4 000 0 5.9 0
00000 27. 40 n 0 0 U
00000 0 11.8 0 000
0 0 1.4 T.9 0 0 0 0 0 0 0
0 0 1.2 0 0 0 7.1 0 0 0 0
0 s Below detection limit
MILS > 10' Hicrocr«**/KG (ppb) DRY WT.
Location
ssssssss
SB- 4
SB- S
SB- 9
SB- 9
SB- IS
S8-21
SB-24
S8-26
SB-29
SB-29
SB-30
SB-32
Depth
SSSSSSS3S
f-11*
14'-H"
9"-12"
18"-IS"
10--12'
19--21'
12"-14"
10"-12*
10--12*
22'-24'
20'-22'
14--16'
PCB- PCB-
1254 1280
sssassstsssss
0 0
0 0
4583. 0 0
9444.5 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
4.4'.
000
szssz:
0
0
0
0
308.0
0
0
0
4.9
0
0
4.3
4.4'-
DOE
sssrs*
0
0
0
0
0
0
0
0
0
0
9.5
2.7
4.4'
DOT
ssss
0
0
0
0
426.
0
0
0
2.
0
3.
0
.
ALDRIN
ssss r »r ss
0.26
0
0
0
0 0
0
0
0
2 0
0
4 0
0
DIEL-
DRIN
33S3SS::
0.87
0
0
0
0
0
0
13324.9
7.4
0
0
0
ENDRIN
SSSSSS*
0.71
0
0
0
0
0
0
0
0
0
0
0
ENDOSOLFAN
SOLFATE
!3£3sss:s:s<
0
0
0
0
0
0
0
0
0
U
0
0
MEPTA-
CHLOR
;«2S~£S *•
0.33
0.67
0
0
0
1.70
0
0
0
0
0
U
LIN-
DANE
E S "S£ = S
0.26
0
0
0
0
0
2.0
0
0
U
0
U
08
oo
U - Below detection Unit
-------
TAPLF 3
POLYNUCLZAR AROMATIC HYDROCARBONS
GROOPED BY RING STRUCTURE
(PAH Compounds Detected in Soils at MWDS)
Two Ring PAHs
Acenaphthene
Naphthalene
2-Methylnaphthalene
Three Ring PAHs
Phenanthrene
Anthracene
Fluorene
Oibenzofuran
Four Ring PAHs
Benzo(a)anthracene
Chrysene
Fluoranthene
Pyrene
Five Ring PAHs
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(Jc)fluoranthene
Dibenzo (a, hj.anthracene
Six Ring PAHs
Benzo(g,h,i)perylene
Indeno(1,2,3-cd)pyrene
-------
TABLE A
Summary of Semivolatiles Analysis in Soils at MWDS
S08JTACS SEDIMENT SAMPLES Mlcrofr.ms/KC (ppb) DRY WT.
Location
:z::::::
I- 2
I- 3
Depth
:s:«r:::
Surf.
Surf.
DEHP
rsssrsss
270.21
Q
DKBP
0
0
DIBSNZO-
FURAN
0
0
2-RIHC
PAH's
0
0
3-RING
PAH's
U
U
4-RING
PAH's
0
323.39
S-RIHC
PAH'j
0
a
S-RING
PAH' a
0
0
SOILS 0'-2'
U - Below detection limit
Hicrocriu/KC (ppb) DRY HT.
Location
SB- 1
Depth
ssssssss
0'-2'
DEHP
zssssxsss;
1308.40
DNBP
0
DIBENZO-
FORAN
0
2-RIHC
PAH's
::===:::=:
0
3-RINC
PAH's
:=::=:::::?==
0
4-RING
PAH's
0
S-RING
PAH's
0
6-RINC
PAB's
asasssassasss
0
0 : Below detection Halt
SOILS 2'-4' Bicrocraas/XG (ppb) DRY HT.
Location
=::»:::
SB- 7
SB- 9
SB- 19
Depth
ssssssss
2'-4'
2'-4'
2'-4'
DEHP
sssssssss
0
372.21
0
DNBP
nrss=ss
0
0
0
DIBENZO-r
FORAN
333S2S3S33.
0
0
0
2-RING
PAH's
:s:s:ss::s::
1370.38
0
270.54
3-RINC
PAH's
sssssssssss
2788.78
0
225 . 39
4-RIHC
PAH's
!=s=as2S3
53666.09
514.74
2471.40
S-RIHC
PAH'S
==:::=:=:=:
24424.31
211.28
2937.13
S-RING
PAH's
::::r:s=:::=
0
0
1952.37
U : Below detection liaut
SOILS 4'-10' Hlerocrams/KG (ppb) DRY WT.
Location
:::==:::
SB- 15
SB-23
Depth
S33SS33S
S'-IO'
DCHP
32Z3S3
0
0
DNBP
S333SCSSS23
0
0
DIBCNZO-
rORAH
sassasssss
0
0
2-IING
PAH's
S3S3S3233S::
0
0
3-RING
PAH's
•sasssasss:::
339.00
12311.36
4-RINC
PAH's
:2:ssssa2a:
3636.00
24743.93
S-RIHC
PAH's
;:::£;::=:::
0
0
6-RINC
PAH's
sssassass
a
0
U s Below detection
SOILS > 10* f!lcro«T»«s/KC (ppb) DRY MT.
Location
:::::a:s
SB- 1
SB- 2
SB- 2
SB- 3
SB- 4
SB- 5
SB- 6
SB- 7
SB- 8
SB- 9
SB-IS
SB-26
SB-29
SB-29
Depth
::s:sss*
13'-15'
16--18*
22'-24'
16"-16*
9"-ll '
14* -16*
11'-13*
10" -12"
13'-15'
9"-l2"
!0'-12"
10'-12'
I0'-l2'
22'-24'
DtHP
:sss*ass:i
1046.46
0
0
976.23
305.36
657.25
0
606 . 08
1229.53
0
0
0
620.68
381.62
DNBP
:2S333ZS9
419.64
0
0
0
0
0
0
0
0
0
0
0
0
0
DIBENZO-
rORAH
::=£=:=::r:
0
0
18261.47
0
0
0
0
0
0
0
678.00
0
0
U
2-RING
PAH's
:s33SE3:::
1452.03
1867.12
46604 ..SO
0
0
0
0
0
956.17
0
715.00
1752.41
0
285.61
3-RINC
PAH's
SSSISSSSSSX
7398 96
2117.92
170180.04
U
U
U
0
0
5874.97
0
4802.00
0
272.39
1325.32
4-RIHC
PAH's
:::::::::::
18290.55
U
194036.18
0
0
0
978.02
0
13056.65
111656.69
0
0
372.72
3202.52
S-RING
PAH's
::r=::=s:i:s
3629.94
0
19690.91
U
U
0
0
U
U
64764.34
U
0
U
3172.69
6-RIMG :
PAH i
::i = "iss: :
1386 22
0
3310.04
0
U
3
0
0
U
16706. SS
U
0
0
1207 TO
08
53
OC
0 : Below detection Uait
-------
TABLE 5
Summary of Volatile Organic Compound Analysis in Soils at MWDS
SOILS 2'-4'
VOLATILE OHGANIC OOKPOACS
/H; (ppb) DRY vfT.
Location
SB-23
SB- 30
Depth
2'-4'
2'-4'
PENTA-
1.2-Dcs TCE VINYL CHLOBQ- Z-BUTA- Z-HBCA- Z-POTTA- ACE- CASSX ETHYL- ».?.o-
10' Hierocms/KC (ppb) CRY
Location
SB- 1
SB- 2
SB- 2
SB- 6
SB- 8
SB- 9
SB- 9
SB-IS
SB-IS
SB- 19
SB- 19
SB-20
SB-21
SB-21
SB-26
SB- 27
SB-29
SB-30
SB-31
Depth
13--1S-
16"-18"
22"-24'
Il'-l3"
13--1S-
9'-12"
16* -18*
10*-12"
36*-38"
28'-30'
33' -35'
20' -22*
UT-12'
19 ' -21 '
10'-12'
18 '-20-
20--22'
31 '-3I*1
1.2-DCE TCE
(TU)
1274.1 29S.O
U 0
0 0
29.8 0
10.3 U
116.3 0
8047.1 U
0 0
70. S 284.6
119.6 30.4
24.0 0
0 50.0
60.0 7.0
76.0 746.0
1287.4 8.4
0 0
0 0
917.6 52.5
1£7r*£ £ Cl
VINYL
Cl-
0
0
0
0
0
11.2
0
0
0
U
U
0
0
0
18.0
U
0
U
•«* u
PENTA-
CKLOfiO-
PKEHOL
U
0
0
0
u
19775.0
0
U
U
0
0
U
U
U
U
U
0
0
u
2-8UTA-
NONE
0
0
U
U
0
0
U
0
0
U
U
U
0
U
U
U
U
69.7
U
2-HEXA-
NONE
0
U
u
u
u
C.9
U
U
U
0
u
0
u
u
u
0
u
u
II
4-H.
2-PSKTA-
NONK
U
0
U
28.6
0
8.3
968.9
0
0
0
0
u
u
u
0
0
0
u
u
ACE-
TONE
0
0
U
U
U
190.
0
U
0
0
0
0
U
0
0
0
0
u
II
CARBON
OI-Ss
U
U
0
9.8
0
4 0
0
0
0
0
0
U
0
U
0
0
0
123.3
11
BENZENE
0
U
U
U
0
0
U
U
0
0
0
u
0
u
u
u
u
u
II
ETHYL- a.p.o-
BEKZEXE TOLOENE XYLEXES
U U 1703.7
0 U 26.1
U 0 15.5
19.9 13.7 31.1
215.7 39.6 305.6
72.0 94.2 193.9
U 139.592 229.917
U 0 29.0
42.1 35.9 21.0
20.6 5.9 32.6
16.9 U '.1.6
U 0 U
U U U
0 U U
1267.1 20.6 1226.4
U 16.4 U
U U U
176.9 154.5 444.9
1..1E+6
-------
TABLE 6
Summary of Analysis of Perched Zone Ground Water at MWDS
ORGANIC COMPOUNDS
WATER SAKPLING PHASE 1
PARTS PER BILLION
(Perched Zone)
COHPOOMO
ssszszsssszszszszzszzszzszsss
l.l-DICHLOROETHANE
1.1-DICHLOROETHENE
1.2-DICHLOROETHANE
1.2-DICHLOROETHENE (TOTAL)
2-BOTANONE
2-HEXANOHE
2.4.S-TRICHLOROPHENOL
4-HETHYL-2-PENTANONE
CHLOROETHANE
CHLOHOFORH
BENZENE
8IS(2-ETKYLKEm> PHTHAUTE
ETHTLBENZENE
NAPHTHALENE
TETRACHLOROETHENS
THICHLOROETHE.HE
TOLOENE
VINYL CHLORIDE
•.p.o-XYLSNSS
METHVI FNE CHLORIDE
nw-2S
::::::=::
0
0
u
900.0
U
43.0
9.0
100.0
0
0
0
12.7
0
12.6
U
0
0
90.0
es.o
u
INORGANIC COMPOUNDS
WATER SAMPLING PHASE i
PARTS PER .1ILIION (ppa)
(Perched Zone)
Parameter
ZINC
NITRITE. (N02)
NITRATE. (M03)
CHLORIDE. (CD
FLUORIDE. (F)
SOLFATE. (S04)
tlw-25
..
..
482.0
65.2
376.0
(--) = B«Jow OSEPA's Hinlsua Acceptable Concentration
0 : Below detection Halt
INORGANIC COMPOUNDS
WATER SAMPLING PHASE 2
PARTS PER MILLION
(Perched Zone)
P*.r«Mtc
:ss:zxs»s
ZZNC
NITRATE!
CHLORIDE.
FLUORIDE.
SOLFATE.
r
szszsz
(N03)
(CD
(F)
(S04)
HW-2S
MW-llS
HW-12S
HW-13S HW-lS
HH-16
HW-17
HW-18
szzzezszzzzisszszszzzzzzzzzzssszzzizzzzszzzszszzszzzzzzz
—
_—
424
85
328
0
2
0
1.5
28.3
120.0
04
165.0
7.8
_v
—
—
••
—
11
633
--
••
—
4
0
• -
-•
--
1250
1280
67
1700
0
0
2
0
--
..
107.0
18.3
•"
"
—
378.0
6.8
~"
(--) - B«lo« USEPA'i ntni«u« Acceptable Concentration
ORGANIC COMPOUNDS
UATES SAMPLING PHASE 2
PARTS PER BILLION (pool
(P*rch«4 Zone)
COMPOOKO
izszssszisstzszzzzzzszzzzriss
1 . 1 -OICHLOROCTHANE
1.1-DICHLOROCTHEHE
1.2-OICHLOROETHANE
1.2-DICHLOROETHENE (TOTAL)
2-80TANONE
2-HEXANONE
4-METHYL-2-PENTANONE
4.4--DDT
BEMZKHC
BIS(2-ETHYLHEXYL) PHTHAUTE
CHLOBOKTHANE
CHLOROrORfl
ETHTLBENZENE
NAPHTHALENE
TETRACHLOROETHENE
TRICHLOROETHENE
TOLOENE
VINYL CHLORIDE
M^frlYLENE^LORIDE
HW-2S
szzsszsz
0
6.6
0
330.0
g
0
0
0
12.0
11. 1
0
0
170.0
15.9
0
0
27.0
48.0
"5:8
BW-HS
zszszszs
0
0
U
U
U
0
0
u
u
0
0
0
0
u
0
0
u
0
0
MM- 125
::::::::
0
u
u
0
0
u
u
0
0
0
0
0
u
0
0
u
u
u
0
HM-13S
z:s::z:s
U
U
(I
0
u
0
u
a
a
15.0
u
u
u
u
0
u
u
0
u
HH-1S
zszssssz
U
u
0
u
0
0
0
0
u
19.4
U
0
U
0
0
0
0
a
0
KU-16
:zs:z:z::
U
U
u
u
u
0
u
u
u
u
u
u
u
u
u
u
u
u
a
SX-17
::::«:
U
U
U
63 0
11.0
U
41.0
U
28 0
14.6
U
U
86 0
U
53
U
300.0
10.0
150 0
J1W-18
::z:::::t:
<3
U
U
26 0
U
U
U
U
U
U
U
u
u
u
u
8.3
a
u
u
"D
08
OD
U - B«lou detection
-------
TABLE 7
Summary of Analysis of Glacial Aquifer Ground Water at MWOS
ORGANIC COMPOUNDS
WATER SAF.PLING PHASE 2
PARTS PER BILLION (?pb)
(Glacial Aquifer)
COMPOUND
1.1-DlCHLOROSTHANS
1.1-DICKLOROETHENS
1.2-DICHL080ETHANE
1.2-DICHLOROETHENE (TOTAL)
2-BUTANONE
2-HEXANONE
4-HETHYL-2-PENTANONE
BENZENE
BIS(2-ETKYLHEXYL) PHTHALATE
CHLOROETHANE
CHLOROFORM
ETHYLBENZENE
NAPHTHALENE
TETRACHLOROETHENE
TRICHLOROETHENE
TOLUENE
VINYL CHLORIDE
ME?HYLENE CHLORIDE
COMPOUND
1,1-DICHLOROCTHANE
1.1-DICHLOROCTHENE
1.2-DICHLOROeTKANE
1.2-DICHLOROETHENE (TOTAL)
2-BUTANONE
2-HEXANONE
4-HETHYL-2-PENTANONE
BENZENE
BIS(2-ETKYLHEXYL) PHTHALATE
CHLOROETHANE
CHLOROFORM
ETHYLBENZENE
NAPHTHALENE
TETRACHtOBOETHENE
TRICHLOeOETHENE
TOLUENE
VINYL CHLORIDE
•.p.o-XYLSNES
METHYLENE CHLORIDE
HM-1
97.0
0
U
U
0
0
0
U
U
230
0
0
0
0
0
0
0
0
u
HH-9
U
a
0
u
0
T
0
a
9.7
0
0
0
0
0
0
0
0
0
u
HW-20
0
0
7.8
1400
0
u
u
S.2
9.3
0
0
0
0
0
100
0
290
U
nv-io
a
a
0
18.0
0
a
0
0
67.1
0
0
0
0
6.7
0
0
0
0
10.0
Dp- 20
0
0
5.6
960
0
0
0
0
41.7
0
0
0
0
0
96.0
0
300
8
HV-llD
0
0
0
0
0
0
0
0
84.3
0
0
0
0
0
0
0
0
0
u
Av-20
0
0
6.1
1193
U
0
a
S.I
2S.5
U
U
0
0
0
98.0
0
263
I
nw-120
U
0
0
u
u
0
0
0
122
0
0
u
0
7.7
0
U
U
0
U
MW-3
U
6.3
U
1TOO
U
0
0
6.S
29.5
U
0
a
0
u
380
0
790
3
U s Be
BW-13D
U
U
U
500
U
U
a
s.o
11.4
0
0
0
0
7.9
30.0
0
160
0
U
HW-4
U
U
6.3
0
U
0
0
0
13.7
U
0
U
0
U
12.0
0
0
12°.0
LOU Det4
Dp- I 3D
U
0
0
440
U
0
a
s.o
44.9
0
0
a
0
0
29.0
0
160
0
HW-S
0
U
U
0
u
0
u
0
17.5
U
9.7
U
U
U
12.0
0
0
S
let Ion
Av-130
0
a
a
470
0
u
0
s.o
26.2
0
0
U
0
6 . S
29. S
0
170
0
9
n-6
0
0
52
160
0
U
0
u
u
u
u
0
u
0
7.1
0
150
ft
Lieut
«V-l«
U
0
U
U
U
a
U
a
10.4
0
u
u
u
0
S.I
0
u
u
u
HW-7
0
0
5.4
u
u
u
u
u
16.3
U
U
0
U
U
u
a
u
J
*.-l9
U
U
u
u
0
a
u
0
26.2
0
0
u
u
0
28:7
0
0
a
u
««-6 !
0
u
u
0
u
5.3
U
U
64.3
U
U
U
U
J
U
U
0
uu
•
nw-20
U
U
U
y
u
0
0
0
12.1
0
u
u
•J
u
u
u
0
1)
u
0 = B«lov Detection Ll»l".
INORGANIC COMPOUNDS
HATtl SAMPLING PHASE 2
PARS PER MILLION (ppa)
(Gl«ct*l Aquifer)
p^.^t^r
SSSSS3SSSSSSSX3S
ZTMC
U T TV ITS t HO2 1
NITBATI. (NO3)
CHLOilDE. (Cl)
FLUORIDE. (F)
SULFATB. (S04)
IW-1
:«:::::
*.
--
--
-™
HV-20
.-..3::
..
609.0
101.0
414.0
BM-3 HW-4
s::::::::::::
676.0
462.0
46.6
• • ••
tiM-s nw-6
:s:sssssssss3s:
•• ••
1960.0
86.0
1510.0
IW-7
• e.
_.
_.
"-
nw-a
SS3"S
'
- —
_.
..
--
(•-> > B«lo« USEPA's HlnlnuB Acceptable Concentration
P.r.-t.
==========
ZINC
UTTftfTiT
UfTBATC
CHLOilDE.
FLUORIDE.
SULFATE.
r
:::*"
(MO21
f NO3 1
(Cl)
(F)
(S04)
BW-9
33:33::
-—
RW-iO
nw-uo
nw-120
ttw-130 nw-14
nw-i9
::::::* :::7::3:::::::3::::::::3::::3:333::
._
_»
8.
4
— ^
^_
4
1
nu-20
33:333:
3.3
-—
..
311.0
..
--
467.0
..
..
291.0
»—
4.
370.
6
0
274
7
435
0
2
S
_.
392
0
_,
,_
403.0
(--) - Below USEPA's ninlnua Acceptable Concentration
o
oo
3D 33
OO
-------
20
were left untreated. This analysis, commonly referred to as a
baseline risk assessment, is documented in the draft Risk
Assessment for the Motor Wheel Disposal Site, October 1990 and the
Technical Memorandum dated December 21, 1990.
The baseline risk assessment for the Motor Wheel site evaluated the
risk from different areas or units independently. The following
units were evaluated:
0 Surface soil and potentially eroded waste mass material
« Surface water sediments
* Surface water
# Perched zone ground water
0 Glacial aquifer ground water
0 Glacial aquifer phthalates
Although the fugitive dust pathway was not evaluated in the Risk
Assessment the selected remedy will reduce the potential exposure
through this pathway by capping the unexcavated areas of the site.
Toxicity Assessment
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 J^jare
multiplied by the estimated intake of a potential carcinogen in
mg/kg-day and the expected duration of chronic exposure, to provide
an upper-bound -estimate of the excess lifetime cancer risk
associated with exposure at that intake level. Values for these
parameters are included in Table 8 for the chemicals used in the
Risk Assessment. 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.
Reference doses (RfDs) have been developed by U.S. 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
-------
TABLE 8
DRAFT
ENS
Summary of U.S. EPA Dose-Response Data Used In the MWDS Risk
Assessment
Chemical
Arsenic
Copper
Chromium (VI)
Nickel
Lead
Potentially Carcinogenic PAH
Reference Doee (mg/kg/day) Slope Factor {mg/kg/day)"1
Oral Oral
1E-3(a)
5E-3(a)
' 2E-2(a)
Noncarcinogenic PAH O.OW(b)
4,4-000
4.4-ODE
4,4-DDT SE-4(a)
AMrin 3E-5(a)
Owldrin 5E-5(a)
Heptachlor 5E-4(a)
Bis-{2-ethylhexy1)phthalate 2E-2(a)
1,2-dichloroethene
1^-dichloroethane
Benzene
Tetrachloroethene
Trichloroethene
Vinyl Chloride
2-butanone • 5E-2
2-taxanon* 5E-2
4H7>ethyl-2-pentanone 5E-2(a)
Ethylberuene lE-1(a)
Toluene 3E-1(a)
Xyterws 2E+0(a)
1.1-dichloroethane lE-1(a)
Naphthalene 4E-3(a)
(a) U.S. EPA HEAST. 4th quarter, 1969.
(b) The value for naphthalene was used.
(c) The value for benzo(a)pyrene was used. ;
H.5(c)
3.4E-1(a)
l.7E-H(a)
1.6E*1(a)
4.5E+0(a)
1.4E-2(a)
9.lE-2(a)
2.9E-2(a)
S.lE-2(a)
1.lE-2(a)
2.3E+0(a)
9.lE-2(a)
Motor WhMl/314*408-224
5-2
OctotMrigoo
-------
22
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. Values for these
parameters are included in Table 8 for the chemicals used in the
Risk Assessment.
Pathway and Risk Assessment
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). An excess lifetime cancer risk of 1 X 10~6
indicates that, as a plausible upper bound, an individual has a one
in one million chance of developing cancer as a result of site
related exposure to a carcinogen over a 70 year lifetime under the
specific exposure conditions at the 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 exposure within a single
medium or across media.
Soil
The soil concentrations used to evaluate baseline risk were those
considered accessible or potentially accessible to a transient
visitor to the site. Surface soil samples, soil borings to a depth
of 2 feet, and waste mass samples from banked areas with the
potential for erosion were considered. Exposure routes were dermal
contact and inadvertent ingestion. The following chemicals were
selected based on their toxicity and frequency of occurrence:
* arsenic * PAHs
« dieldrin « heptachlor
« 4,4-DDT » zinc
* bis(2-ethylhexyl)phthalate
Potential adverse human health effects were estimated for two types
of chemicals: those with noncarcinogenic effects and those with
-------
23
carcinogenic effects. Risks from potential carcinogens are
expressed as a probability, e.g., 1 in 1 million (1 x 10~6). The
hazard index (HI) risk from noncarcinogenic chemicals is expressed
as a fraction of the estimated dose divided by a regulated
acceptable dose. An HI greater than 1 is considered unacceptable.
The sum of the dermal contact and ingestion pathways excess
lifetime cancer risk (ELCR) was 1.46 X lO'^for soil. The HI risks
for adults and children are 1.44 X lO'^and 6.91 X lO'Vespectively.
Sediments and Surface Water
Concentrations of contaminants in the four on-site ponds were used
to determine risk due to exposure to sediments and surface water.
A scenario in which an adult may swim in the pond seven times and
a child four times per year was assumed to provide the visitation
rate at the site. Both ingestion and dermal contact were the
assumed exposure routes. The following compounds were selected for
evaluation based on their toxicity and frequency of detection:
« 4,4-DDE
* 4,4-DDT
The ELCR from contact with sediment via dermal contact and
ingestion at the pond was 1.50 X 10~ . The His for adults and
children was 1.92 X 10~5and 6.07 X 10~4,respectively. The ELCR
from surface water by dermal contact and ingestion was 6.59 X lO'11,
Summed His were 4.79 X 10~7for an adult and 9.1 X 10~7for a child.
Perched Zone Ground Water
For the purposes of this risk assessment it was assumed that the
perched zone ground water may flow into the glacial aquifer and be
consumed. Two exposure routes were considered: the ingestion of
drinking water and dermal contact while bathing. Both adults and
children were considered. The following chemicals were selected
based on their toxicity and frequency of detection in the perched
zone:
« 1,2-dichloroethene
» 1,2-dichloroethane
B benzene
« tetrachloroethene
« trichloroethene
» 2,4,6-trichlorophenol
* 1,1-dichloroethene
« 4-methyl-2-pentanone
« ethylbenzene
* toluene
* methylene chloride
* di-n-octylphthalate
-------
24
« fluoranthene
* pyrene
» vinyl chloride
* bi(2-ethylhexyl)phthalate
* 2-butanone
» chloromethane
« naphthalene
* 2-methyl naphthalene
* xylenes
« nitrate
« sulfate
The ELCR from dermal contact with and ingestion of water from the
perched zone is 7.16 X 10~ . The summed His for the same exposure
routes for adults and children are 3.85 X 10~1and 6.28 X 10""1
respectively. The majority of the risk from the perched zone
ground water is via ingestion. Vinyl chloride, makes up the
majority of the risk, 92%, or a risk of 6.61 X 10
-4
Aoruifer Ground Water
For the purpose of risk assessment, theoretical exposure routes
were assumed since the glacial aquifer is not currently a source of
drinking water in the vicinity of the site. Ingestion and dermal
contact while bathing were considered in this analysis. Both
adults and children were considered. The following chemicals were
selected for use in the analysis based on their toxicity and
frequency of detection:
« 1,1-dichloroethene
* bromomethane
* chloroform
» 1,2-dichloroethene
* benzene
* 2-hexanone
a tetrachloroethene
* nitrate
* chloroethene
* 1,2-dichloroethane
« bis(2-ethlyhexly)phthalate
* vinyl chloride
« 1,1-dichloroethane
« trichloroethene
« methylene chloride
« sulfate
The ELCR from dermal contact with and ingestion of glacial aquifer
ground water is 5.47 X 10". The summed His for the same exposure
routes for adults and children are 9.60 X 10~1and 1.56 X 10 ,
respectively. The majority of the risk associated with the glacial
aquifer is due to ingestion. Vinyl chloride makes up 98.7 % of the
risk.
-------
25
Risks for the pathways considered in the assessment are summarized
in Table 9.
Ecological Impacts
The site consists of the excavated pit area, which has some
vegetative cover that offers only minimal habitat for wildlife, and
the unexcavated area, which contains sparse grasses, indiscriminate
scrub vegetation, and bushes. The Motor Wheel site is a small
animal habitat. Transient deer, geese, ducks, and domestic animals
have been noted on and in the vicinity during site visits. No
evidence of adverse environmental effects, in the form of damaged
or killed vegetation, loss of habitat, loss of food sources, and
toxic effects to terrestrial and/or aquatic ecosystems were
documented during site investigations. A U.S. Department of the
Interior Fish and Wildlife Service conducted species/sensitive
environment search did not indicate the presence of endangered
species in the vicinity of the Motor Wheel site.
Bis(2-ethylhexyl)phthalate, the chemical of potential concern in
surface water, was reported at a concentration of 5 /ig/liter in
surface water at the site based on the detection limit for the
compound.
The acute and chronic ambient water quality criteria (AWQC) for the
protection of aquatic life for bis(2-ethylhexyl)phthalate are 11
Mg/liter and 3 /ig/liter respectively. The present concentration of
this compound is above the chronic AWQC. Since the chronic AWQC
for phthalate is determined for sensitive species living in streams
and rivers and since none of these species have been identified on
site no environmental risk is assigned for surface water.
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.
VII. DESCRIPTION OF ALTERNATIVES
The alternatives analyzed for the remedial action at the Motor
Wheel Disposal site are presented below. These are numbered to
correspond with the numbers in the RI/FS Report. The alternatives
which have been assembled to include remedial activities which
address both the ground water contamination and waste mass area are
as follows:
-------
DRAFT
TABLE 9
Risk Summary Table
Expoaure Pathway
Excess Lifetime Cancer Risk
HI Adurt
HI Child.
Soil
Sediment
Surface Water
Dermal Contact
Ingestion
Dermal Contact
Ingestion
Dermal Contact
Ingestion
Summed Riak for Surface Ex-
poaure
Groundwater Perched Zone
Dermal Contact
Ingestion
Groundwater Glacial Aquifer
Dermal Contact
Ingestion
Glacial Groundwater Phthalate
Dermal Contact
Ingestion
5.79 x 1
-------
27
» Alternative 1:
a Alternative 2:
» Alternative 3:
» Alternative 4:
* Alternative 5:
» Alternative 6:
« Alternative 7:
« Alternative 8:
ALTERNATIVE 1:
NO ACTION
No Action
Access Restrictions and Ground Water
Monitoring
Capping of Disposal Area and Natural
Attenuation of Ground Water
Capping of Disposal Area with Collection
and Treatment of Ground Water from the
Glacial Aquifer
Capping of Disposal Area with Collection
and Treatment of the Ground Water from the
Perched Zone and Glacial Aquifer
Removal of VOCs in the Fill Mass by Soil
Vapor Extraction, Capping of the Disposal
Area, and Extraction and Treatment of the
Ground Water from the Perched Zone and
Glacial Aquifer
Excavation and Disposal of Fill Material
with Extraction and Treatment of Ground
Water from the Perched Zone and Glacial
Aquifer
Excavation and Incineration On-site of the
Fill Mass with Extraction and Treatment of
the Ground Water from the Perched Zone and
Glacial Aquifer
Capital Cost: $5,000
Annual Operation and Maintenance (O&M) Costs:
Net Present Worth (PW): $1,941,200
$125,950
The Superfund program requires that the "No Action" alternative be
evaluated at every site to establish a baseline for comparison.
Under this alternative no further action would be undertaken to
prevent exposure to the soil, sediment, or groundwater at the site
or to prevent migration of the contamination off site.
Although no further remedial activities would be required a
quarterly ground water monitoring program would be established for
at least nine of the existing wells to evaluate ground water
migration from the site. This ground water monitoring program
would be implemented as a part of all alternatives.
-------
28
ALTERNATIVE 2:
ACCESS RESTRICTIONS AND GROUND WATER MONITORING
Capital Costs: $140,600
Annual O&M Costs: $154,950
Net PW: $2,522,600
The limited action alternative provides institutional controls,
access restriction and ground water monitoring in the perched zone
and the glacial aquifer. Components of the alternative are:
» Necessary improvements in the current fencing and
additional fencing around the perimeter of the
unexcavated waste disposal area to restrict access,
thereby reducing potential exposure and risk to human
health and safety,
* Use of deed restrictions to limit the development and
use of land and groundwater on the Motor Wheel Site,
* Installation of additional monitoring wells in the
glacial aquifer, and
* Monitoring at selected perched zone and glacial
aquifer wells.
ALTERNATIVE 3:
CAPPING OF DISPOSAL AREA AND NATURAL ATTENUATION OF GROUND WATER
Capital Costs: $7,207,700
Annual O&M Costs: $168,900
Net PW: $9,804,100
This alternative'would include placing a multi-media cap over the
entire fill area. Cost for the cap in this description and in the
following alternative descriptions is based on the specifications
of Michigan Act 64 as presented in the FS. This cap also meets and
exceeds the requirements of the RCRA Subtitle C cap. It may be
appropriate to modify the FS cap design and still meet the
performance standards of Michigan Act 64 and RCRA Subtitle C.The
cap over the fill area would cover about 11.3 acres. To ensure
proper design and installation of the cap, it may be necessary to
extend the cap past the landfill property boundaries. Access to
adjacent property may be required.
Backfilling would be necessary where the northern portion of the
fill area is exposed in the excavation. A 4 to 1 slope would be
established and the cap extended over the slope. Approximately
125,000 cubic yards of backfill material would be needed. In order
to maintain the integrity of the cap, the backfilled portion will
also be included under the cap. The cap area would therefore be
expanded to about 14.9 acres. The landfill boundary as well as the
-------
29
backfill area and pit would be fenced to restrict access. Design
and construction of the cap would take approximately 1 year.
No ground water treatment would be required for this alternative.
Natural attenuation and degradation of contaminants would be relied
upon to remediate the ground water. Although a time within which
ground water standards would be achieved by natural attenuation can
not be determined, it would be a very long time. Ground water
monitoring as described in Alternative 2 would be implemented as
part of this alternative and for the purpose of cost estimation
will continue for at least thirty years.
The fencing and ground water monitoring elements of Alternative 2
would also be implemented for this alternative.
Site maintenance would consist of mowing and regular inspections of
the cap for signs of damage or deterioration. Depending on the
magnitude of the damage or deterioration excavation of the cover
soil and repair of the barrier may be necessary.
ALTERNATIVE 4:
CAPPING OF DISPOSAL AREA WITH COLLECTION AND TREATMENT- OF THE
GLACIAL AQUIFER
Capital Costs: $10,127,000
Annual O&M Costs: $1,055,500
Net PW: $26,352,600
This alternative combines the capping of the disposal area and
backfilled area as in Alternative 3 with extraction and treatment
of ground water from the glacial aquifer. As with alternative 3 an
Act 64 cap is used for cost estimation.
The ground water from the glacial aquifer will be extracted by
installing recovery wells or trenches downgradient of the disposal
site where compounds of concern were detected in ground water. It
is estimated that approximately 1.66 X 109 gallons of water will
have to be recovered and treated by air stripping to meet the
objectives of the ground water cleanup. The time to meet these
objectives is estimated to be 9 years assuming a linear removal
rate from an extraction well system. In practice however, there is
substantial doubt that cleanup goals could be achieved within this
time. Costs included here assume 30 years of treatment.
The glacial aquifer extraction system would include four 6 inch
extraction wells screened at a depth of 55 to 75 feet. A buried
collection and transfer system would carry the extracted ground
water to the on-site treatment facility. The exact number of
wells, and their location, depths, and pumping rates, would be
determined based on ground water flow and transport modeling and
aquifer pump tests. An option to install ground water collection
-------
30
trenches could be investigated during the detailed design phase.
Pre-treatment of ground water to remove iron and manganese by
aeration, clarification and filtration may be necessary. This
system would reduce iron and manganese to acceptable concentrations
and also remove sufficient total suspended solids to meet discharge
requirements.
Removal of organics from the ground water would be accomplished by
air stripping and carbon adsorption. Air stripping would be used
to remove the volatile organics from the ground water through mass
transfer to the gaseous phase and collection by carbon adsorption
for subsequent destruction. Aqueous phase carbon adsorption would
be used for removal of non-volatile organic compounds from the
ground water. Fluoride would be removed from the ground water by
reaction with activated alumina. The process yields calcium
fluoride which can be disposed as solid waste. The treated ground
water will be discharged to the Lansing wastewater treatment plant
(POTH). Monitoring would be implemented to ensure compliance with
POTW pretreatment requirements and other State and Federal water
quality criteria.
ALTERNATIVE 5:
ACT 64 CAP AMD COLLECTION AMD TREATMENT OF THE PERCHED AND GLACIAL
AQUIFERS
Capital Costs: $11,083,300
Annual O&M Costs: $1,277,400
Net PW: $30,720,300
This alternative consists of capping the disposal area with an Act
64 cap as described in Alternative 3 and extracting and treating
the perched zone and the glacial aquifer ground water. The capping
would significantly reduce leachate generation due to surface water
infiltration through the landfill. A slurry wall would be
installed at the western and southern boundary of the disposal area
to act as a barrier to block the movement of off-site ground water
toward the disposal area, thus shortening the time for dewatering
of the perched zone.
The slurry wall would be installed to a depth below the fill
material. The slurry wall would be approximately 2,000 feet long
and 35 to 40 feet deep depending on the depth to the clay layer
supporting the perched zone.
Ground water would be collected from both the perched zone and the
glacial aquifer and treated as described for Alternative 4.
The contaminated ground water in the perched zone would be
extracted by placing the collection wells into the fill.
Essentially, the objective would be to dewater the landfill by
applying a retroactive leachate recovery system. The conceptual
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31
design would include five extraction wells screened at depths of 25
to 35 feet.
ALTERNATIVE «
ACT 64 CAP, SOIL VAPOR EXTRACTION AND GROUND WATER TREATMENT OF
PERCHED AND GLACIAL AQUIFERS
Capital Costs: $12,533,000
Annual O&M Costs: $1,277,400
Net PW: $32,169,800
This alternative provides the sane elements for the capping of the
waste mass and the collection and treatment of ground water from
the perched zone and the glacial aquifer as Alternative 5.
Alternative 6 adds a soil vapor extraction system (SVE). SVE
removes VOCs from the subsurface through a series of extraction
wells by application of vacuum on soil above the water table. The
VOC vapors are collected and processed through a liquid-vapor
separator. Collected liquids would be either: (1) treated in a
vacuum assisted aeration unit, causing the VOCs to volatilize so
that they can be processed through an activated carbon substrate,
or; (2) transported to the ground water treatment system for
processing with the ground water from the perched zone and the
glacial aquifer. The objective of the SVE is to reduce the
transfer of VOCs into the perched zone and glacial aquifer thereby
shortening the time required to meet ground water cleanup goals.
The SVE treatment system would be continued until a significant
reduction in the amount of VOCs being recovered by the system was
achieved. The time to reach this point of reduction is uncertain
since development of quantitative monitoring procedures would have
to be developed.
ALTERNATIVE 7A
EXCAVATION AND DISPOSAL OF FILL OFF-SITE AND GROUND WATER TREATMENT
OF THE PERCHED AND GLACIAL AQUIFER
Capital Costs: $140,987,000
Annual O&M Costs: $1,292,400
Net PW: $160,854,400
This alternative consists of excavating and disposing of fill
material at an off-site RCRA compliant facility and extracting and
treating ground water from the perched zone and the glacial aquifer
as described for Alternative 5.
Excavation of all fill material would result in 256,000 cubic yards
requiring disposal. This total volume considers increase of the
volume of 210,000 cubic yards of waste due to handling and addition
of reagents. It is estimated that approximately 427 days would be
required to complete the excavation and shipment of all waste.
Waste would be treated at the facility if necessary to meet land
disposal restrictions. This work would probably take 1.5-2.0 years
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32
to accomplish. The excavated area would be backfilled following
completion of the excavation and shipment of waste.
Ground water in the perched zone and in the glacial aquifer would
be treated in the same manner as for Alternative 5.
ALTERNATIVE 7B
EXCAVATION AND DISPOSAL OF FILL ON-SITE IN RCRA CELL, GROUND WATER
TREATMENT OF PERCHED AND GLACIAL AQUIFERS
Capital Costs: $21,466,000
Annual O&M Costs: $1,292,400
Net PW: $41,313,400
This alternative consists of excavation of the same volume of fill
material as for Alternative 7A and extraction and treatment of the
perched zone and glacial aquifer ground water as for Alternative 5.
Excavated waste will be disposed of on-site in a disposal cell
which meets the requirements of RCRA Subtitle C/Act 64. Waste will
be treated as needed to meet land disposal restrictions. Disposal
cells of this nature are designed with double liners and double
leachate collection systems. The cell will cover approximately
5.75 acres. Construction of the on-site cell is expected to take
3-4 years.
ALTERNATIVE 8
EXCAVATION AND INCINERATION OF FILL ON-SITE AND GROUND WATER
TREATMENT OF PERCHED AND GLACIAL AQUIFERS
Capital Costs: $117,270,600
Annual O&M Costs: $3,567,400
Net PW: $154,590,100
This alternative consists of excavating fill material and treating
it in an on-site incinerator, and extracting and treating ground
water from the perched zone and the glacial aquifer as in
Alternative 5.
Excavated waste would be incinerated on-site in a mobile rotary
kiln incinerator. It is estimated to take approximately 10 years
to incinerate the waste mass using a rotary kiln with a capacity of
120 tons/day. Disposal of some residue at an off-site disposal
facility or in an on-site RCRA Subtitle C/Michigan Act 64 disposal
cell might be required depending on the composition of the residue.
VIII. SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES ANALYSIS
This section profiles the performance of the preferred alternative
against the nine criteria, noting how it compares to the other
options under consideration. The nine criteria are as follows:
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33
0 Overall Protection of Hunan Health and Environment addresses
whether or not a remedy provides adequate protection and describes
how risks posed through each pathway are eliminated, reduced, or
controlled through treatment, engineering controls or institutional
controls.
« Compliance with ARARs addresses whether or not a remedy will
meet all of the applicable or relevant and appropriate requirements
of other Federal and State environmental statutes and/or provide
grounds for invoking a waiver.
o Long-ten Effectiveness and Permanence refers to the magnitude
of residual risk and the ability of a remedy to maintain reliable
protection of human health and the environment over time once the
cleanup goals have been met.
0 Reduction of Toxicity, Mobility, or Volume Through Treatment is
the anticipated performance of the treatment technologies that may
be employed in a remedy.
« Short-term Effectiveness refers to the speed with which the
remedy achieves protection, as well as the remedy's potential to
create adverse impacts on human health and the environment that may
result during the construction and implementation period.
0 Implementability is the technical and administrative feasibility
of the remedy, including the availability of materials and services
needed to implement the chosen solution.
0 Cost includes capital and operation and maintenance costs.
0 state Acceptance indicates whether, based on its review of the
RI/FS and Proposed Plan, the State concurs with, opposes, or has no
comment on the preferred alternative.
0 Community Acceptance is assessed in this Record of Decision
following review of the public comments received on the RI/FS
report and the Proposed Plan.
GROUND WATER
1. Overall Protection of Human Health and the Environment
The "No-Action" alternative (Alternative 1) does not provide
overall protection of human health and the environment because it
allows continued migration of the plume. Alternatives 2 and 3 will
not provide overall protection of human health and the environment
because these also allow continued ground water migration. The
ground water component of Alternative 4 may not provide adequate
protection since the contaminants in the perched zone will not be
collected and treated. Alternatives 5 through 8 will be protective
of human health and the environment because they completely address
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34
the ground water threat by capturing and treating all of the ground
water contamination.
2. Compliance with ARARs
Groundwater ARARs include the requirements of the federal Safe
Drinking Water Act, 1929 Michigan Public Act (HPA) 245, as amended;
1979 MPA 399, as amended; and 1982 MPA 307, as amended. The
cleanup standards for ground water are the Michigan Act 307 Type B
standards, which treat each contaminant to the IxlO"6 level or the
Human Lifecycle Safe Concentration (HLSC), and Federal Drinking
Water Standards (MCLs).
Alternatives 5 through 8 would comply fully with the ground water
ARARs. As Alternative 4 does not capture all of the ground water
contamination plume, it does not meet ground water ARARs in the
perched zone. Since Alternatives 1 through 3 do not actively
restore the aquifer, and rely on natural attenuation, dispersion
and degradation, these will not meet ARARs, within a reasonable
time frame.
Air ARARs include the requirements of 1965 Michigan Act 348, as
amended and the Federal Clean Air Act. All Alternatives which rely
on the operation of the air stripper will comply with both of these
ARARs.
Since the ground water components of Alternatives 1 through 3 are
not considered protective of human health and the environment and
are not expected to meet ARARs within a reasonable time frame, they
are not available for selection and will not be discussed through
the remainder of this analysis.
3. Long-term Effectiveness and Permanence
Alternatives 5 through 8 all provide a high degree of long-term
effectiveness and permanence at the site by collecting and treating
the contaminated ground water and assuring that the contaminated
ground water does not impact the Saginaw Formation. Alternative 4
would only be capable of capturing most of the plume as opposed to
the entire plume and therefore leaves the risk of contaminated
ground water from the perched zone discharging to the glacial zone.
All alternatives also include "institutional controls" which would
restrict the use of groundwater in the site area until cleanup
levels are met. Ground water monitoring would also be used for
each alternative.
4. Reduction of Toxicity, Mobility, or Volume of the
Contaminants Through Treatment
Alternatives 4 through 8 are all able to sufficiently reduce the
ground water contamination through treatment, although
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35
Alternative 4 relies on natural attenuation, dispersion and
degradation for contaminants in the perched zone. The contaminants
will be removed from the water by several methods including air
stripping and granular activated carbon (GAC). The GAC would be
thermally regenerated at a RCRA compliant facility, thus destroying
the contaminants and reducing the contaminant's mobility, toxicity
and volume.
5. Short-ten effectiveness
Potential risk to remedial workers exists for the pump and treat
alternatives because installation of extraction wells would be
intrusive into the waste mass and could liberate volatile
materials. Risks associated with the operation and maintenance of
the treatment systems would also be present. These risks are
expected to be mitigated through proper health and safety
procedures and operational precautions.
The time required for achievement of remedial action objectives for
groundwater is expected to be long for all alternatives.
Alternatives 4 through 6 are expected to be close to meeting the
groundwater cleanup objectives after 30 years; however, the
asymptotic approach to the cleanup objectives may require greater
remedial time frames or modification of the cleanup strategy for
the site.
6. Implem«ntability
Installation of the pump and treat systems is expected to consist
of available technologies using known construction techniques. O&M
requirements of such systems will require long-term attention on a
daily or weekly basis and must be included in implementation plans.
Ability to obtain approvals from agencies may be difficult for
Alternative 4, which has the potential for downgradient movement of
the constituents from the perched zone while dispersion,
attenuation, and degradation are proceeding. Additionally it may
be difficult to monitor and enforce deed restrictions and ground
water use restrictions during this period.
Effluent from the treatment process would flow to the Lansing POTW.
Monitoring would be implemented to ensure compliance with POTW
requirements. The regulated parameters, discharge standards and
monitoring frequency will be determined during the remedial design.
7. COSt
Costs for each alternative are presented earlier in "The Summary of
Alternatives". The present worth cost differential to treat the
glacial aquifer (Alternative 4) as compared to merely monitoring
the release (Alternative 3) is $16,548,500. The incremental
present worth cost required to treat both the perched and the
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36
glacial aquifer (Alternatives 5-8) as compared to Alternative 4 is
$4,367,700.
SOURCE CONTROL
1. Overall Protection of Hunan Health and the Environment
Alternatives 1 and 2 for source control would not control exposure
to the waste fill and would allow for continued migration of fill
contaminants into ground water. These alternatives would therefore
not be protective of human health and the environment. Since these
alternatives do not provide adequate protection to human health and
the environment, they are not available for selection and will not
be discussed through the remainder of this source control analysis.
The source control component of Alternatives 3 through 6 is
protective of human health and the environment because it reduces
the migration of contaminants from the fill to groundwater. These
alternatives also reduce direct human contact risks. Alternative
6 provides some additional benefit in that SVE will reduce the
total mass of VOCs in the vadose zone of the landfill, thus
potentially decreasing the time required to treat the glacial
aquifer.
Alternatives 7A and 7B are protective of human health and the
environment because these require the removal of contaminated soil
which would minimize the risk of contaminant migration to ground
water. The risk of human exposure would also be eliminated. The
difference is that for Alternative 7A, disposal occurs off-site,
while Alternative 7B involves construction of an on-site
containment cell.
Alternative 8 is protective of human health and the environment,
since the waste will be excavated and incinerated. The risk due to
direct contact with the waste and migration to the ground water is
eliminated.
2. Compliance with ARAR*
The major source control ARARs are Michigan Acts 307 and 64.
Alternatives 3 through 6 include an Act 64 hazardous waste cap.
Alternatives 7A and 8 are expected to meet Act 307, Type B
standards, since the source will be removed and disposed of off-
site or incinerated on-site. These standards are based on the
levels required to protect ground. water from the migration of
contaminants from the fill and levels required to protect against
unacceptable risk through direct human contact with contaminants in
the fill.
Alternative 7B is capable of complying with ARARs since the
containment cell will be designed to meet the requirements of Act
64. Alternatives 3 through 6 and 7B would be considered
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37
Type C cleanups under Act 307 because waste is being left on-site.
3. Long-Ten Effectiveness and Permanence
Alternatives 7A and 8 will result in a low magnitude remaining risk
and high degree of permanence once the treatment or off-site
removal is completed. Each may leave some residual soil
contamination but at levels which would be protective of human
health and the environment.
Alternative 7B will result in a low magnitude residual risk since
the waste is fully contained on-site. The RCRA-cell will provide
a higher degree of control than capping alone due mainly to the
underliner system and leachate collection system in the RCRA cell.
Alternatives 3 through 6 will reduce the chance of direct human
contact as long as the cap is maintained but because these only
cover, not remove, the contamination, a moderate long term risk of
continued impact on human health and the environment remains.
Alternative 6 may provide slightly greater long-term effectiveness
since the VOCs are treated. The long-term effectiveness of
Alternatives 3 through 6 depends on maintenance of the cap.
4. Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternatives 6 and 8 treat the contaminated fill and thereby reduce
the toxicity, mobility and volume.
In Alternative 8, incineration is expected to provide the greatest
degree of reduction of toxicity, mobility, and volume of the waste
mass, since organic constituents present in the waste mass will be
destroyed. The process is effective and irreversible. Residuals
from the process will include gasses, ash, and water that require
subsequent treatment. It is expected that the ash volume will
roughly be equivalent to the volume of material incinerated. Such
residuals may require disposal, possibly as hazardous waste.
In Alternative 6, SVE would be employed to remove VOC materials
from the vadose zone in the fill mass. The amount of constituents
that would be removed or destroyed is difficult to assess because
the performance of the SVE system is dependent on many site-
specific factors such as location of significant volume of VOCs in
the fill mass, the heterogeneity of the fill mass, and other
issues. The degree of reduction is not expected to be great, since
the majority of the constituents to be removed were identified in
groundwater beneath the fill mass. SVE will not be effective for
removal of VOGs in the perched or glacial aquifers.
The source control component of Alternatives 3,4,5 and 76 do not
involve treatment and therefore do not satisfy the criteria to
reduce the toxicity, mobility, or volume of the contaminated fill.
Alternative 7A removes the contaminated soil from the site but does
not reduce toxicity, mobility, or volume of the soil if treatment
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38
is not required prior to disposal at the off-site facility.
5. short-Tent Effectiveness
All of the alternatives involve construction and have a degree of
risk associated with potential exposure to dust, vapors, and
contaminated waste. This potential would be minimized, as much as
possible, through good construction practices and engineering
controls.
The short-term exposures associated with Alternatives 3 through 6,
and 7B would come about during construction of the cap or RCRA-
cell.
The greatest potential for short-term exposure is associated with
Alternatives 7A, 7B and 8. These alternatives involve excavating
the waste and either incinerating it or landfill ing the waste on or
off-site, which could result in increased dust, vapors, and the
potential for direct contact with contaminated waste. Alternative
7A involves negative short-term impacts since contaminated material
will be transported off-site. Alternative 6 poses some short-term
risk due to extraction of VOCs from the fill.
For Alternatives 3 through 6, it is expected that construction will
take approximately 1 year. The SVE portion of Alternative 6 is
expected to operate approximately 3-5 years. Alternative 7A will
take 2-3 years to off-site dispose all the waste. Alternative 7B
will take 3-4 years to construct a RCRA-cell. It is expected to
take over 10 years to incinerate the waste under Alternative 8.
6. implementability
For Alternatives 3 through 5, the ease of construction, operation,
and ability to undertake additional remedial actions (if necessary)
are not expected1 to present constraints to implementation. The
ability to monitor the effectiveness of the alternatives is also
expected to be easily achieved. The implementability of cap
installation may present some technical challenges due to the
topography of the fill mass and the presence of the adjacent sand
and gravel pit. These challenges can be overcome with available
technologies. Installing a hanging slurry wall could be difficult
due to topography and geology.
For Alternative 6, successful operation of installing an SVE system
would be difficult due to the heterogeneous nature of the waste.
Also, the success of SVE would be highly dependent on the degree to
which distinct volumes of materials containing VOCs could be
located within the waste mass. For Alternative 7B, implementation
is more difficult. From a technical perspective, it is possible to
excavate the waste mass and construct a RCRA cell on-site. Where
excavation is concerned, the monitoring requirements will be
extensive and will require that the excavation be halted and
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39
engineering controls be implemented if VOC or dust concentrations
exceed allowable criteria. The implementation of a RCRA cell on-
site also provides some technical difficulties; for example, the
cell will have to be over 30 feet deep with a bottom liner of clay
that is 14 feet thick to be placed on-site.
Incineration capacity may limit the implementation of Alternative
8. In addition, there will be some difficulty in that the waste
will be handled prior to incineration, and the ash will need to be
properly disposed. The substantive permit requirements will also
pose some difficulty.
7. COSt
Costs for each alternative are presented earlier in the "Summary of
Alternatives". The PW cost differential to treat the VOCs via SVE
in Alternative 6 over just capping in Alternative 5 is
approximately $1.5 million. The incremental PW cost above
Alternative 5 to off-site dispose of the fill material (Alternative
7A) is $130,134,100, to build an on-site cell (Alternative 7B) is
$10,593,100, and to incinerate on-site (Alternative 8) is
$123,864,800.
Ground Water and Source Control
8. State Acceptance
The State of Michigan has indicated that it concurs with the
selected remedy for the Motor Wheel site. A letter from the
Michigan Department of Natural Resources indicating this support is
attached.
9. Community Acceptance
In general, the community accepts the selected remedy. Comments
from both the residents of the local community and the regulated
community are addressed in the Responsiveness Summary which is
attached.
II.
The FS examined eight alternatives, and evaluated them according to
the evaluation criteria outlined in the NCP. From these
alternatives, U.S. EPA has selected Alternative 5 for remediation
of the Motor Wheel Site. The alternative includes collection of
ground water from the perched zone and the glacial aquifer and
treatment of the contaminated ground water by air stripping,
granulated activated carbon and activated alumina. The ground
water collection system will include a slurry wall to enhance the
dewatering of the perched zone.
Ground water remediation will continue until the cleanup standards
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40
shown in Table 10 are met. These standards were determined
according to procedures set forth in Rule 299.5709 of the Michigan
Environmental Response Act (Act 307), for compliance with type B
criteria for ground water in aquifers, based on individual risk for
each compound. The risk-based levels may be below the current
analytical detection levels for these chemicals. Therefore, the
cleanup levels for these indicator chemicals will be determined by
the available analytical procedures or the risk-based levels
defined above, which ever is higher. Method detection limits
("MDL") applied here are based on Analytical Detection Level
Guidance for Environmental Contamination Response Activities under
Act 307 Rules (memorandum of James G. Truchan, MDNR, April 1, 1991)
using best practical judgement based on the capabilities of the
reference method and capabilities of government and commercial
labs.
The goal of the ground water element of this remedial action is to
restore ground water to its beneficial use, which is, at this site,
use for residential purposes. Based on information obtained during
the remedial investigation and on a careful analysis of all
remedial alternatives, U.S. EPA and the State of Michigan believe
that the selected remedy will achieve this goal. It may become
apparent, during implementation or operation of the ground water
extraction system, that contaminant levels have ceased to decline
and are remaining constant at levels higher than their remediation
goal. In such a case, the system performance standards and/or the
remedy may be reevaluated.
The operating system may include:
a) discontinuing operation of extraction trenches in areas
where cleanup goals have been attained;
b) alternating .pumping at trenches to eliminate stagnation
points; and
c) pulse pumping to allow aquifer equilibration and
encourage adsorbed contaminants to partition into ground
water.
A cap will be installed over the waste mass area to control
infiltration through the waste and to reduce risk of exposure to
the waste. The cap will be designed and constructed to meet the
specifications of the Michigan Act 64. The cap will cover a total
of about 14.9 acres including the slope of the mined out area.
The cost of the preferred remedy is estimated to be:
Capital Costs: $11,083,300
Annual O&M Costs: $1,277,400
Net PW: $30,720,300
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10
CONTAMINANTS
VOCs
1 , 1 -Dichloroethene
1 ,2-Dichloroethane,
1 ,2-Dichloroethene
2-Butanone
2-Hexanone
4-Methyl-2-pentanone
Benzene
Chloroethane
Chloroform
Chloromethane
Ethylbenzene
Methylene Chloride
Naphthalene
Tetrachloroethene
Trich loroethene
Toluene
Vinyl Chloride
Xylenes (total)
Semi-VOCs
Bis(2-ethylhexyl)phthalate
2,4,5-Trichlorophenol
Inorganics
Ammonia
Chloride
Fluoride
Iron
Lead
Nitrate
Sulfate
Zinc
MEAN
CONC.
3.06 -
2.6
258.38
5.75
- >
9.5
6.9
11.48
-
4.9
33.9
4.13
6.75
2.81
33.43
42.75
85.10
38.13
19.36
22.19
_
401,470
22,286
3,190
-
161,851
432,800
2,600
MAX.
CONC.
7
7
1,700
11
43
41
28
230
9.7
5
170
10
16
5
380
300
790
150
122
25
453.000
1 ,380,000
101,000
-
300
1,249,600
1 ,700,000
10,000
MCL
7
5
70
-
-
-
5
-
-
-
-
-
-
-
5
-
2
-
-
-
.
-
4,000
-
.
10,000
-
-
MCLG
7
0
70
-
-
-
0
-
-
-
-
-
-
-
0
-
0
-
-
-
.
-
4,000
-
10,000
-
-
SMCL
.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
.
250,000
2,000
300
-
-
250,000
5,000
Exceeded 1 x 10* Lifetime
Incremental Cancer Risk
YES
YES
NA
NA
NA
NA
YES
NA
NA
NO
NA
NA
NA
YES
YES
NA
YES
NA
YES
YES
NA
NA
NO'
NA
NA
NA
NA
NA
MI. Act 307
TypeB
7
0.4
70
400
5
400
1.0
9.0
6.0
3.0
700"
5.0
40
0.7
3.0
800"
0.02
300
2
700
34,000
250,000
2,000
300
5
10,000
250,000
1,000
MDL
r
1
1
1
5
5
5
5
5
.
- '
-
-
3
-
-
20
All concentrations in Mg'L MCL: Maximum Contaminant Level MCLG: Maximum Contaminant Levels Goals
SMCL: Secondary MCL MDL: Method Deletion Limit (-) : Not established
NA: No slope factor available for these compounds, therefore cancer risk was not calculated.
*: Exceeded Hazard Index (HI) of I for noncarcinogenic effects in adult and child.
**: Michigan Act 307 Type B Secondary Maximum Contaminant Level or taste/odor threshold value, if lower than toxicologically-based standard.
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42
Based on current information, this remedy appears to provide the
best balance of trade-offs among the alternatives with respect to
the nine criteria that EPA uses to evaluate alternatives.
Z. STATUTORY DETERMINATIONS SUMMARY
l. Protection of Hunan Health and the Environment
The selected remedy provides adequate overall protection of human
health and the environment, by capping the waste mass area and by
pumping and treating the contaminated ground water in the perched
zone and in the glacial aquifer. Institutional controls including
deed and usage restrictions will be sought in addition to the
engineered controls, to implement and maintain risk reduction due
to the waste fill mass and during the period of active ground water
remediation.
Short term risks associated with the installation of ground water
recovery wells and collection system and the operation of the air
stripper will be managed through the use of good engineering
practice and monitoring of appropriate media.
No environmental impacts have been identified for the site. This
is largely due to the fact that impacts from the site have been to
the ground water, soil, and sediment in the site areas where
disposal activities took place.
2. Attainment of ARARs
The selected remedy will be designed to meet all applicable or
relevant and appropriate requirements (ARARs) of Federal and more
stringent state environmental laws. The following discussion
provides the details of the ARARs that will be met by the selected
alternative.
Action-Specific ARARs;
Clean water Act (CWA) of 1977, as amended [33 D.8.C.
1251]
40 CFR 122 and 40 CFR 125 - The National Pollutant
Discharge Elimination System (NPOES), which specifies the
scope and details of the NPOES permit applications,
including limitations, standards, and other permit
conditions which are applicable to all permits including
specified categories of NPDES permits. Also specifies
schedules of compliance and requirements for recording
and reporting monitoring results. Administered by MDNR
under 1929 Michigan Public Act 245, as amended, Part 21.
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43
Michigan Act 348 of the Public Acts of 1965, as amended:
Air Pollution Act
Part 2 - Air Use Approval, which specifies information
required for a permit to install, construct, reconstruct,
relocate, or alter any process, fuel burning or refuse
burning equipment, or control equipment which may be a
source of air contamination.
Parts 3, 7 and 9 - Emissions, which specifies emission
limitations for particulates, fugitive dust, VOCs, and or
contaminants which may be injurious to or adversely
affect human health or welfare, animal life, vegetation,
or property, or interfere with normal use and enjoyment.
Part 10 - Intermittent Testing and Sampling, requirements
which may require performance of acceptable performance
tests.
Resource conservation and Recovery Act/ Subtitle C (RCRA),
1976; U.S.C. 6901; 1979 Michigan Hazardous Waste Management
Act, PA 64
40 C.F.R. 264 - Ground Water Protection Standards, which
provide technical requirements for long-term monitoring
while the ground water treatment element is active and
for at least the first five year review period following
completion of the ground water cleanup.
Chemical-Specific ARARs:
Clean Water Act (CWA) of 1977, as amended [33 U.S.C.
1251]
40 CFR 129 - Toxic Pollutant Effluent Standards, which
establish toxic pollutant effluent standards and
prohibitions of specific compounds for specified
facilities discharging into navigable waters. 40 CFR
129.104 sets the ambient water criterion in navigable
waters.
Public Health Service Act: Title XIV, as amended by the
Safe Drinking Water Act [42 U.S.C. 300] and 1979 Michigan
Safe Drinking Water Act, Act 399
40 CFR 141 - National Primary Drinking Water Regulations,
which specify maximum chemical contaminant levels (MCLs)
of public water systems for inorganic and organic
chemicals, maximum contaminant goals (MCLGs) of public
water systems for organic chemicals, and establishes
national revised primary drinking water regulations of
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44
MCLs for organic chemicals. Public Act 399 incorporates
the MCLs for a public drinking water supply system, which
includes ground water used as a drinking water supply.
Clean Air Act of 1963, a* amended [42 U.8.C. 7401]
40 CFR 50 - National Primary and Secondary Ambient Air
Quality Standards, which establish national primary and
secondary ambient air quality standards. The appendices
provide methods and procedures for measuring specific air
pollutants.
40 CFR 61 - National Emission Standards for Hazardous Air
Pollutants, which identifies substances that have been
designated hazardous air pollutants, and for which a
Federal Register notice has been published, and specifies
prohibited activities, describes procedures for
determining whether construction or modification is
involved, prescribes methods of applying for approval,
and covers the manner in which start-up notification is
to be provided.
Act 245 of the Public Acts of 1929, as amended: Water
Resources Commission Act
Part 4, Rule 57 - Water Quality Standards (Surface Water
Quality Standards), which establishes limits for all
waters of the State for the following components:
dissolved solids, pH, taste and odor producing
substances, toxic substances, total phosphorous and other
nutrients, and dissolved oxygen.
Rule 98 - Antidegradation, requires maintenance and
protection of existing waters when water quality is
better than water quality standards.
Part 22 - The State has identified this rule as an ARAR.
The State concurs with the remedy selected, and has
stated that in applying Act 307 requirements to the
ground water treatment, the remedy selected will satisfy
the requirements of Act 245. The United States disagrees
that Act 245, as interpreted and applied by the State in
this matter, is an ARAR. This issue is the subject of
litigation in U.S. v. Akzo Coatings of America, appellate
case numbers 89-2902 and 80-2137, and may be reassessed
after a decision has been rendered.
Act 348 of the Public Acts of 1965, as amended: Air
Pollution Act
Part 3 - Emission Limitations and Prohibitions
Particulate Matter, which establishes standards for the
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45
density of emissions and emission of particulate matter.
Act 307, Michigan Environmental Response Act. The rules
promulgated pursuant to the Act set requirements for
evaluating remediation of hazardous waste sites in
Michigan. There are three types of remediation specified
by this act; Type A, B, and C.
Act 347 of the Public Acts of 1972: Soil Erosion and
Sedimentation Control Act
Part 17 - Soil Erosion and Sedimentation Control -
Establishes general soil erosion and sedimentation
control procedures and measures. Also, specifies earth
change requirements and soil conservation district
standards and specifications.
3. Cost-Effectiveness
The selected remedy provides overall cost-effectiveness. An
adequate degree of permanence is achieved by containment of the
waste fill mass by capping and by extraction and treatment of the
contaminated ground water.
4. Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the
Maximum Extent Practicable
The selected remedy provides the best balance with respect to the
nine evaluation criteria as described in Section IX of this Record
of Decision. Treatment technologies are utilized to the maximum
extent practicable by treatment of contaminated ground water by
pump and treat, which includes treatment of stripped volatiles.
This alternative is further balanced with respect to the nine
criteria because a permanent solution which utilizes treatment
technologies for the ground water is being selected. The ground
water monitoring component of the selected remedial action will
assure that concentrations of contaminants do not increase during
implementation.
5. Preference for Treatment as a Principal Element
By treating the contaminated ground water the selected remedy
satisfies the statutory preference for remedies that employ
treatment of primary threats and which permanently and
significantly reduces toxicity, mobility, or volume of hazardous
substances as a principal element.
The selected remedy reduces the primary threat at the site, direct
contact with and ingestion of contaminated ground water. Because
treatment of the threats due to the waste fill mass was not found
to be practicable, this element of the remedy does not satisfy the
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46
statutory preference for treatment as a principal element.
Treatment is a principal element of the ground water remedy which
reduces the risk of exposure through ingestion and direct contact
with the contaminated ground water by use of pump and treat
technology.
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RESPONSIVENESS SUMMARY
MOTOR WHEEL DISPOSAL SITE
Overview
At the start of the public comment period which began July 15, 1991
the United States Environmental Protection Agency (EPA) proposed a
remedial alternative which addressed both groundwater and soil
contamination at the Motor Wheel Disposal site ("Motor Wheel11),
Lansing, Michigan. The alternative, as specified in the proposed
plan, called for capping of the on-site waste mass area and for the
extraction of contaminated groundwater from the perched zone and
the glacial aquifer with treatment via air stripping. Capping of
the waste mass area is projected to take approximately one year
and extraction and treatment of the groundwater was projected to
last for at least 30 years. In addition, the Motor Wheel proposed
plan required fencing of the site area, land use restrictions,
groundwater monitoring and long-term maintenance of the air
stripper. Comments received by the EPA and those voiced at the
public meeting in Lansing expressed concern about some of the
details of the proposal.
This Responsiveness Summary addresses the concerns expressed by the
public and the potentially responsible parties (PRPs) in written
and oral comments received by EPA at the public meeting and during
the public comment period.
The responsiveness summary is divided into the following sections:
A. Background on community involvement;
B. Summary of comments received during the public comment
period, including responses to the comments;
C. Other comments received by the EPA.
A. Background on CoroMinity Involvement
Community interest in the Motor Wheel site was strong at the start
of the RI/FS but has been somewhat inconsistent since that time.
There is no formal citizens' group specifically for Motor Wheel.
However, the site has been included as a topic for attention by the
north Lansing citizens information committee which meets
periodically to discuss environmental problems associated with
several sites in the north Lansing area. The Ingham County
Department of Public Health (ICDPH) and the Michigan Department of
Public Health (MDPH) participate in the citizen's information
committee as well.
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The most significant early community relations issue was the
concern over the length of time that was required to begin clean up
at the site.
B. Summary of Comments Received Purina the Comment Period
The public comment period on the proposed plan for the Motor Wheel
site was held from July 18, 1991 to August 19, 1991. Comments
received during this public comment period are listed below. Some
of the comments have been paraphrased so they could be more
effectively summarized in this document. For original comments in
their entirety, the reader is referred to the public meeting
transcript and written comments which are available for review at
the public information repository at Lansing Public Library in
Lansing, Michigan.
A response follows each comment. Comments and responses have been
divided into three sections and are further categorized by topic
within each section where appropriate. The three sections are:
1. summary of comments from the local community, including written
and oral comments submitted during the July 24, 1991 public
meeting;
2. Comments of the Ingham County Health Department;
3. Comments from elected government officials; and
3. Summary of comments from the potentially responsible parties
(PRPs).
1. Summary of Coipments from Residents
COMMENT: A commenter expressed opposition to Alternative 8 of the
Feasibility Study (FS) which included incineration of the waste
mass material.
U.S. EPA R«spon»«: The U.S. EPA evaluated all alternatives
described in the FS, including incineration, using appropriate
guidance and the criteria for comparative analysis in the National
Contingency Plan (NCP). The results of this analysis indicated
that the proposed plan alternative is appropriate to meet the
remedial objectives at the site. It is not the intention of U.S.
EPA to incinerate any of the waste mass material from the Motor
Wheel site.
Comment: A commenter at the public meeting expressed concern that
the Risk Assessment was incomplete since it did not evaluate the
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potential for contamination of the Saginaw aquifer in the vicinity
of the site especially since the RI indicated that the shale
aquitard may be discontinuous to the south and southwest of the
site. Additionally the commenter was critical of the length of
time that elapsed from the recognition of need for further
investigation of the bedrock aquifer in the Remedial Investigation
Report and the start of field work to evaluate the continuity and
integrity of the shale aquitard and the water quality in the
Saginaw aquifer near the site.
U.S. EPA Response: U.S. EPA recognizes the need to evaluate the
potential for contamination of the Saginaw aquifer which is the
source of the Lansing public water supply. At the direction of
U.S. EPA and MDNR an investigation was designed to provide data for
the evaluation of the current impact of the Motor Wheel site on
this aquifer and the potential for future impact on the aquifer if
no action is taken at the site. The study includes the
installation of four wells into the sandstone member of the Saginaw
formation. Core samples will be examined to determine the
thickness and competence of the shale and the nature and
permeability of the sandstone. Water samples will be collected and
analyzed during well installation to evaluate water quality in all
geologic horizons and to determine the optimum depth for well
completion. Samples will then be analyzed to fully evaluate water
quality in that portion of the Saginaw aquifer.
The planning and execution of an investigation of this significance
required several months after all parties to the RI/FS
Administrative Order recognized the need for the investigation.
During this period of discussion and planning, monitoring of the
ground water from the Lansing Board of Water and Light (BW&L) wells
in the vicinity confirmed that water quality at those locations is
currently not being impacted by constituents from the site.
Monitoring of the BW&L water quality will continue until the
investigation is complete.
COMMENT: A commenter was concerned that the proposed alternative
for capping of the waste mass area would not adequately reduce the
risk for continued contamination of the ground water and that
because there could be drums present in the waste mass the threat
to the ground water would continue unless treatment was perpetual.
The commenter recommended Alternative 7B requiring excavation of
the waste mass and containment on-site in a hazardous waste cell as
the most appropriate remedy.
U.S. EPA Response: Capping is commonly selected at Superfund sites
to reduce ground water degradation caused by infiltration of
precipitation through heterogeneous waste. Analysis of the
performance of these remedies indicate a high degree of long-term
effectiveness in protecting human health and the environment by
reducing the production of leachate caused by this infiltration.
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Evaluation of alternatives indicates that a high degree of long-
term effectiveness can also be expected at the Motor Wheel site by
installation of an Act 64 cap and continuation of appropriate
operation and maintenance.
At sites where there are many drums mixed with low-level
heterogeneous waste it is beneficial to remove these drums prior to
capping. Investigation has indicated that significant numbers of
drums are not present at the Motor Wheel site, since drums were
not found during recent on-site test pitting in the vicinity of
several geophysical anomalies it is not likely that the long-term
effectiveness of the Act 64 cap will be reduced or that perpetual
treatment of the ground water will be necessary.
Containment of the waste in an on-site cell offers only marginal
increase in the long-term effectiveness over capping because of
circumstances at the Motor Wheel site. Infiltration reduction is
similar since the cap design is the same for both alternatives.
Although some advantage in the restriction of movement of
contaminants may be demonstrated for the liner, initially this
advantage is reduced because the selected alternative also includes
treatment of the perched zone ground water. Movement of
contaminants from this zone will be essentially precluded after
installation of the slurry wall and dewatering of the perched zone.
Attainment of this marginal increase in long-term effectiveness is
not cost-effective since it would cost $10.5 million more, while
producing very limited additional benefit.
COMMENT: A comment suggested that U.S. EPA include monitoring of
the local residents during any cleanup and consider a buy out of
some of the residents. He also suggested that U.S. EPA consider
recommendations in the recent Michigan State University report
regarding risks.
U.S. EPA Response: Before U.S. EPA considers any action at a
Superfund site a site specific risk assessment is completed
following guidance developed by the Agency for that purpose. The
assessment evaluates both the current and potential risk to human
health and the environment associated with the site. The
assessment examines all reasonable exposure scenarios. Because of
the uncertainties involved, assumptions which must be made in this
evaluation are very conservative. This assessment is used by U.S.
EPA in making cleanup decisions including decisions regarding the
need for long-term health monitoring or residential buyouts.
Although U.S. EPA appreciates and understands the local residents
concerns regarding their health and property values, assessment at
the Motor Wheel site has not indicated risks of the nature that
could require either long-term health monitoring or buyout of
residential property.
The report referenced by the commenter discusses the need to
address those environmental problems which represent the highest
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risk in order to achieve the greatest benefit. Superfund sites,
which are included on the National Priorities List, fit the
category of environmental problems which represent a high degree of
risk. Further, U.S. EPA agrees with the philosophy of getting the
most from the funds which are available by choosing remedies at
Superfund sites that are cost effective.
2. Comments from the Inaham County Health Department
Mary Hultin of the Ingham County Health Department (ICHD) presented
comments at the July 24, 1991 meeting and submitted the same as
written comments during the public comment period.
COMMENT: The ICHD expressed a preference for Alternative 6 since
the soil vapor extraction (SVE) element may provide more long-term
effectiveness than the selected alternative since it would
potentially reduce the time required to treat the glacial aquifer,
by reducing the total mass of VOCS.
U.S. EPA Response: U.S. EPA maintains that the selected remedy is
appropriate for the site. Remedy selection involves balancing the
trade-offs between alternatives as compared to criteria set forth
in the National Contingency Plan. While U.S. EPA recognizes that
Alternative 6 may provide advantage in short-term effectiveness by
potentially shortening the time for attainment of ground water
cleanup goals and provide some reduction of contaminant volume, the
NCP requires comparative evaluation of alternatives against all
criteria. Additionally the cost effectiveness of Alternative 6 is
uncertain since it is doubtful that the volume reduction could be
accurately determined. Implementation of Alternative 6 also may be
questionable because of the heterogeneous nature of the waste at
Motor Wheel.
COMMENT: Although use of indicator compounds may be appropriate if
carefully chosen the commenter felt that it is important that the
ground water be periodically monitored for all compounds detected
in the glacial and perched aquifers.
D.8. EPA Response: Indicator compounds were selected for the Motor
Wheel risk assessment using criteria described in Risk Assessment
Guidance for Superfund (RAGS). December 1989. Indicator compounds
were determined to be of greatest concern because of their
toxicity, level of concentration, and wide spread occurrence. Some
of these indicator compounds were subsequently used in the baseline
risk assessment to determine need for remediation at the site.
U.S. EPA may periodically monitor for all compounds on the
Hazardous Substance List and TCL. The frequency and parameters
will be determined during design. It is understood that
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determination of compliance with all cleanup standards will be
required for completion of the ground water remedial action.
COMMENT: Fluoride is not considered in the risk assessment
although it is listed as a primary noncarcinogenic concern.
U.S. EPA Response: Risk associated with fluoride was evaluated in
a Technical Memorandum Addendum to the Risk Assessment. Risk
associated with the presence of fluoride in the ground water is
above acceptable levels. The selected remedy includes treatment
with activated alumina for reduction of fluoride concentrations to
Act 307 standards.
3. Comments from Elected Officials
Lynne Martinez, Ingham County Commissioner, District 20, submitted
comments supporting Alternative 6 and the comments regarding long-
term monitoring which were submitted by the Ingham County Health
Department.
COMMENT: The commenter supports Alternative 6 for remediation at
the site rather than Alternative 5. The uncertainty of
implementability of SVE notwithstanding the commenter feels that
the additional cost ($1.5 million) seems a relatively small
additional expense and would offer some benefit in assuring a
reduction in the level of VOCs.
U.S. EPA Response: U.S. EPA maintains that the selected remedy is
appropriate for the site. Remedy selection involves balancing the
trade-offs between alternatives as compared to criteria set forth
in the National Contingency Plan. While U.S. EPA recognizes that
Alternative 6 may provide advantage in short-term effectiveness by
potentially shortening the time for attainment of ground water
cleanup goals and provide some reduction of contaminant volume, the
NCP requires comparative evaluation of alternatives against all
criteria. Additionally the cost effectiveness of Alternative 6 is
uncertain since it is doubtful that the volume reduction could be
accurately determined. Implementation of Alternative 6 also may be
questionable because of the heterogeneous nature of the waste at
Motor Wheel.
COMMENT: The commenter agreed with the comment of the Ingham
County Health Department regarding the inclusion of regular
periodic screening for a broad spectrum of toxic compounds.
U.S. EPA Response: Indicator compounds were selected for the Motor
Wheel risk assessment using criteria described in Risk Assessment
Guidance for Superfund (RAGS). December 1989. Indicator compounds
were determined to be of greatest concern because of their
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toxicity, level of concentration, and wide spread occurrence.
These indicator compounds were subsequently used in the baseline
risk assessment to determine need for remediation at the site.
U.S. EPA may periodically monitor for all compounds on the
Hazardous Substance List and TCL. The frequency and parameters
will be determined during design. It is understood that
determination of compliance with all cleanup standards will be
required for completion of the ground water remedial action.
COMMENT: The commenter requested that the design specifications
for the slurry wall and the clay cap should assure that the two are
contiguous in such a way as to provide for the greatest enclosure
possible of the contaminated mass.
U.S. EPA Response: U.S. EPA does not agree with the commenter that
the slurry wall and the cap should provide contiguous enclosure of
the waste mass since remedial objectives for the site do not
include containment of the waste mass and the two components are
not intended for that purpose. Containment could be provided by
Alternative 7B of the FS which calls for excavation of the waste
mass and containment in an on-site Michigan Act 64 hazardous waste
cell, however, that alternative has not been determined to be
appropriate to address the threat to human health and the
environment at the Motor Wheel site.
4. Comments from Potentially Responsible Parties fPRPs)
Comments from PRPs express concerns in two general areas: concerns
about the selection of the appropriate cap for the waste mass area
and issues concerning collection and treatment of contaminated
ground water.
Cap Requirements
COMMENT: The commenter asserts that Act 64 is neither applicable
nor relevant and appropriate for the capping alternative at the
site.
U.S. EPA Response: U.S. EPA has not identified Act 64 as
applicable at the Motor Wheel site. However, the Agency has
identified Act 64 as relevant and appropriate under the
circumstances at the site. Act 64 is relevant since hazardous
wastes, constituents, and substances are known to have been
disposed of at the site and have been identified in the waste mass
at the site in high concentrations. The types of disposed wastes
identified on the property are primarily solid industrial wastes,
including fly ash, paints, solvents, liquid acids and caustics,
sludges and other wastes. Wastes were disposed of on the
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8
property in tanks, barrels, seepage ponds and open fill operations.
In identifying Act 64 as appropriate at the site U.S. EPA
considered the remedial goals which include source control for the
reduction of contamination of ground water in the perched zone and
the glacial aquifer. Maximum reduction of infiltration is achieved
by capping to meet the Act 64 design requirements.
It is not suitable to consider the circumstances at this site in
the same manner as circumstances at large landfills or large mining
waste sites. The Motor Wheel site can more favorably be compared
to a regulated unit in that the waste mass area can be well defined
both laterally and vertically and estimates of the effectiveness of
the cap in reducing infiltration and generation of leachate can
reasonably be made.
COMMENT: The commenter contends that even if Act 64 is determined
to be an ARAR at the site, the circumstances warrant a waiver. The
circumstances which support a waiver include the ability of an Act
641 cap or a RCRA cap to attain performance standards similar to an
Act 64 cap and result in a significant reduction in the cost of the
preferred remedy, the inconsistent application of the requirements
of an Act 64 cap, and the potential for the Motor Wheel site to be
a fund-financed site in order to preserve the fund.
U.S. EPA Response: U.S. EPA does not agree with the commenter's
contention that a waiver of Act 64 is warranted. The MDNR has
consistently applied Michigan Act 64 to landfills that have
accepted hazardous substances and waste containing hazardous
constituents which have been on the National Priorities List (NPL).
Solid industrial wastes, including fly ash, paints, solvents,
liquid acids and' caustics, sludges and other wastes have been
disposed of at the site. These wastes were disposed of on the
property in tanks, barrels, seepage ponds and open fill operations.
Michigan Act 641 and Act 64 are not considered conflicting
requirements but ones that are in succession to one another. For
this site since hazardous substances were disposed of and ground
water is contaminated by the wastes within the site, Act 64 should
and does take precedence over Act 641 if the facility has accepted
hazardous substances. If these hazardous materials were disposed
of after 1980, then Act 64 is applicable; if these hazardous
substances were disposed of prior to 1980, then Act 64 is relevant
and appropriate. Act 64 is relevant and appropriate for the Motor
Wheel site. This is consistent with the requirements of the NCP.
U.S. EPA disagrees that the performance of an Act 64 cap is equaled
or exceeded by an Act 641 cap. Clearly, the Act 64 cap is designed
to prevent infiltration to a significantly greater degree, as it
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was designed to be used at sites or facilities that disposed of
concentrated hazardous materials. There clearly is not a basis for
waiving the ARAR based on equivalent standard of performance.
Although less costly, U.S. EPA cannot select the 641 cap at this
site, due to considerations including degree of effectiveness,
reliability into the future and protection of human health and the
environment.
COMMENT: The commenter contends that Act 64 should be waived to
preserve the Fund because of the possibility the site may revert to
a Fund financed remedy.
U.S. EPA Response: U.S. EPA considers the possibility of the Motor
Wheel site requiring Fund financing remote since a viable group of
PRPs has been identified that has performed the RI/FS and has
subsequently indicated interest in participating in discussions
regarding the performance of the remedy in their response to
General Notice.
In addition, the fund-balancing waiver would not be considered at
this site even if it were to be a fund-financed site. The fund-
balancing waiver is considered at sites where the cost required to
meet an ARAR will not provide a balance between the need for
protection of human health and the environment at the site and the
availability of funds to respond to other sites that may present a
threat to human health and the environment. The lowest cost where
fund balancing is to be considered would be based on an amount
significantly greater than the cost of remediating similar
problems.
COMMENT: The commenter contends that a final design of a cap at
the site can meet the requirements of Act 64 but not conform to the
design criteria in the proposed plan and the Feasibility Study.
U.S. EPA Response: U.S. EPA agrees with the commenter that the
design specifications in the FS exceed the requirements of Michigan
Act 64 and RCRA Subtitle C for closure of a hazardous waste cell.
The Agency would reasonably expect that a cap design different from
the design shown in the FS could meet relevant and appropriate
requirements of Michigan Act 64 and RCRA Subtitle C for closure and
be protective of human health and the environment at the site since
the FS design includes an additional liner not specified in the
RCRA closure guidance of Act 64 regulations.
COMMENT: The commenter asserted that Alternatives 6 through 8 do
not enhance the public health and the environment and are not cost-
effective. Alternative 6 is not appropriate because SVE would not
be effective based on the conditions at the site. Alternative 7A
is inappropriate because excavation of the waste mass and off-site
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10
disposal poses unreasonable short-term risks without any
appreciable long-term benefit. Alternative 7B is inappropriate
because excavation of the waste mass poses unreasonable short-term
risks and an on-site Act 64 cell is not necessary for the
protection of human health and the environment. Alternative 8
poses the same short-term concerns as Alternatives 7A and 7B, with
the additional problems of the siting requirements and community
acceptance of an incinerator, and the disposal of large quantities
of ash.
D.8. EPA Response: U.S. EPA agrees with the commenter assessment
of the merits of Alternatives 6 through 8. Comparative analysis of
alternatives indicates that the selected remedy provides a better
balance when compared against Alternatives 6 through 8 under the
nine criteria. As the commenter correctly points out the
implementability of Alternative 6 may be difficult because of the
heterogeneous nature of the waste mass. Short-term effectiveness
of Alternatives 7A and 7B is low because of the risks associated
with excavation and handling of the waste. Other less costly
alternatives provide a similar level of long-term effectiveness as
Alternatives 7A and 7B. The high cost with limited benefit
provided by Alternative 8 make it not cost-effective.
COMMENT: The point of compliance for attainment of ground water
cleanup objectives should be the boundaries of the site.
U.S. EPA Response: Because of uncertainties about the level and
source of contamination in the vicinity of the Motor Wheel site
U.S. EPA disagrees that the point of compliance should be the
boundaries of the site. The U.S. EPA's Superfund goal is to return
usable ground waters to their beneficial uses and to protect
against current and future exposure within a timeframe that is
reasonable given .the particular circumstances of the site. The NCP
directs "that for ground water, remediation levels 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".
Further Michigan Act 307 requires that for Type B criteria "the
point of exposure shall be presumed to be any point in the affected
aquifer".
U.S. EPA recognizes that there are other sites in the vicinity of
Motor Wheel which may be potential contributors of contaminants to
the aquifer and that at a future time other strategies may be
feasible and effective in addressing this wider contamination.
However, until uncertainties about these sources have been reduced,
the point of compliance shall be as indicated in the NCP And
Michigan Act 307.
COMMENT: A term for operation for any ground water treatment
system should not be specified since existing knowledge on ground
water treatment indicates that the effectiveness of any ground
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11
water treatment system varies over time and deviates dramatically
based upon certain operational parameters.
U.S. EPA Response: U.S. EPA acknowledges that research into and
experience with ground water pump and treat remedies have suggested
that, in certain instances, low level cleanup goals cannot be
achieved within the estimated time frame. Uncertainty in meeting
cleanup objectives in a specified time is, however, an insufficient
reason for not setting these goals. Progress toward cleanup will
be evaluated after the ground water extraction system is
implemented and, if it is determined that cleanup objectives cannot
be achieved, consideration will be given to alternative methods to
provide protection of human health and the environment.
However, until it is shown that the selected technologies cannot
achieve cleanup goals for this site, the remedy must be designed to
be protective of human health and the environment and comply with
ARARs. Since the stated cleanup goals are based on protection and
ARARs, U.S. EPA believes that this approach to evaluating
effectiveness of ground water remediation is consistent with
Section 300.430(e) of the NCP.
COMMENT: The commenter asserts that Michigan Act 307 Type B
criteria for ground water cleanup are inappropriate since the
remedial goals in the FS indicate that appropriate residual risk
should be in the 10~*to 10~6 range and further that the Type C
standards identified in the FS are the proper ARAR for this site.
The Type C cleanup standards are appropriate at this site because
there is no known current (or foreseeable future) residential or
commercial use of the glacial aquifer. The perched aquifer will be
dewatered and, therefore, is not of concern for future human
consumption.
U.S. EPA Response: In the Superfund process, cleanup remedies are
selected that reduce the threat from carcinogenic contaminants at
sites such that the excess risk from the medium (i.e., soil or
ground water) to an individual exposed over a lifetime generally
falls within a risk range from 10"4to 10~6. U.S. EPA's preference
is to select remedies that are at the more protective end of the
risk range. In fact the NCP suggests that the 10~6risk level be
used for determining remediation goals at sites with multiple
contaminants or exposure pathways (NCP 300.430(e)(2)(i)(A)(2).
Therefore, Michigan Act 307 rules, ARARs for this site, are
consistent with cleanup objectives corresponding to 10~*for ground
water at Type B sites.
As specified in Act 307, the application of Type A, B, or C cleanup
in the State of Michigan is made on a case-by-case basis,
considering the site-specific information. The Type B cleanup
objectives at the site are justified because of the potential
future use of the ground water, the rate and direction of ground
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12
water movement, and the overall mobility and toxicity of the
contaminants. U.S. EPA has determined that Type C cleanup
objectives are not appropriate for this site given the potential
future use of the ground water migrating from the source area. The
U.S. EPA policy under the Safe Drinking Water Act (SDWA) is to
restore ground water resources to beneficial used where
practicable. The target residual risk under the SDWA is consistent
with a Type B cleanup.
COMMENT: Design flexibility should be included for the slurry wall
installation due to concerns over the efficacy of slurry walls.
Flexibility should allow for modification or abandonment of the
slurry wall to account for implementability concerns that may arise
during the design and construction phase of the remedial action.
U.S. EPA Response: The slurry wall was included in the Proposed
Plan as a part of the ground water treatment system based on the
engineering analysis provided in the Feasibility Study (FS)
prepared by the PRPs1 engineer. The FS is an essential data
resource in remedy selection and a major document of record. U.S.
EPA has relied on the FS, among other documents to support its
remedy selection and comparative analysis of alternatives at the
Motor Wheel site. U.S. EPA recognizes that new data may be
presented during detailed design that suggests changes that may
provide greater effectiveness in the implementation of the remedy.
U.S. EPA maintains however, that available data indicates that a
slurry wall is a desirable and necessary adjunct to that ground
water collection system and will be included as part of the
selected remedy.
COMMENT: The ground water treatment technologies and disposal
options for treated water should not be specified.
r
U.S. EPA Response: Wherever possible remedial alternative
processes are described as specifically as possible. U.S. EPA
recognizes that uncertainty is present in these data /that are the
basis for selection of remedial alternatives at Superfund sites.
This uncertainty regarding details of some of the alternatives is
accepted as necessary so that progress toward cleanup can continue.
U.S. EPA disagrees that this specific information should no^, be
used in the selection of a remedial alternative. It does recognize
however, that data, which become available during implementation,
indicating that the selected technology may; be inappropriate,
should be considered. • ''-••'*' '-^ -'"'
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