United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R05-89/112
September 1989
&EPA
Superfund
Record of Decision
Hedblum Industries, Ml
-------
50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R05-89/112
3. Recipient1* Acceasion No.
4. TWe and Subtitle
SUPERFUND RECORD OF DECISION
Hedblum Industries, MI
First Remedial Action - Final
5. Report Date
09/29/89
7. Author(s)
8. Performing Organization RepL No.
8. Performing Organization Name and Address
10. Pro|ect/Taak/Work Unit No.
11. Contncl(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Nun* and Addraw
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. Abstract (Umlt: 200 words)
Hedblum Industries site, an automotive parts manufacturing plant, is approximately one
mile southwest of the town of Oscoda, in AuSable Township, losco County, Michigan. In
addition to the plant, the site consists of a ten-acre industrial park, a wetland area,
and residences including the AuSable Heights subdivision. Ground water flows beneath the
plant and subdivision and discharges via a bayou into the AuSable River. Between 1968
and 1972 the previous plant operators discharged cooling water, rinse water, and
approximately 4,000 gallons of waste TCE onto the ground. In 1973 VOCs were detected in
residential wells in the AuSable subdivision. Contaminated wells were replaced with
deeper wells which by 1977 also showed traces of contamination. Subsequently, the Oscoda
Township Municipal Supply System was extended to residents through the installation of a
new water main. An underground storage tank containing TCE, TCA, and PCE was removed
from the site in 1980. The primary contaminants of concern affecting the ground water
are VOCs including benzene, toluene, xylenes, TCE, and PCE; and metals including lead.
The selected remedial action for this site includes ground water pumping and treatment
using activated carbon adsorption with discharge to the bayou; and ground water and soil
monitoring. The estimated present worth cost for this remedial action is $1,379,000,
which includes an annual O&M cost of $264,000 over 4-5 years.
MI
17. Document An»ly»!» a. Descriptor*
Record of Decision - Hedblum Industries,
First Remedial Action - Final
Contaminated Media: gw
Key Contaminants: VOCs (benzene, toluene, xylenes, TCE, PCE), metals (lead)
b. Identifiers/Open-ended Tern*
c. COSATI Held/Group
IB. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No. of Page*
56
22. Price
(See ANS1-Z39.18)
See Instructions on Revene
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
-------
DECLARATION
SITE
Hedblum Industries
Oscoda, Michigan
OF BASI
decision document presents- the selected remedial action for the
Hedblum Industries site developed in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980, 42
U.S.C. 9601, as amended by the Superfund Amendments and Reauthorization
Act of 1986 and consistent with the National Oil and Hazardous Substances
Pollution Contingency Plan to the extent practicable.
This decision is based upon the contents of the administrative record for
the Hedblum Industries Site.
The State of Michigan does not concur with the U.S. EPA's Record of
Decision. The Michigan Department of Natural Resources (MEWR) has
indicated that they agree with the remedial technology selected by U.S.
EPA to remediate the Hedblum Industries site. However, the State of
Michigan does not concur with the cleanup level for Trichloroethene
specified in the Decision Summary.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if
not addressed by implementing the response action selected in this ROD,
may present a current or potential threat to public health, welfare, or
t_he environment.
OF THE
The selected remedy for the site was developed to protect public health
and the environment by preventing ingestion and inlialation of
contaminants found in the groundwater, and by restoring the contaminated
aquifer.
The major components of the selected remedy are as follows:
4 Installing an extraction well system in the AuSable Heights
subdivision and one well downgradient from the plant.
' Pumping extracted water to the site for treatjnent using activated
carbon.
-------
-2-
4 Discharging effluent water from the treatment using activated carbon.
/•
1 Manitoring groundwater quality at the subdivision throughout the
extent of the implementation of the remedy.
1 Abandoning the six MCNR monitoring wells on site.
The selected remedy is protective of human health and the environment,
attains Federal and State applicable or relevant and appropriate
requirements, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment to the maximum extent practicable for
this site.
This remedy involves groundwater restoration, therefore the remedy will
not result in hazardous substances remaining on site above health-based
levels.
Date
Valdas V.
Regional
U.S. EPA, Re
di^X
lion V
-------
DBCXSIGN SDMMQf
BedbiuB Industries Site
The Hedblum Industries Site, 1000 AuSable Road (Old U.S. 23), is
located approximately one mile southwest of the town of Oscoda in
AuSable Tbwnship, losco County, Michigan (Figures i and 2) . The
AuSable River is approximately 0.8 miles to the east and flows into
Lake Huron which is located 1.2 miles to the east of the site. The
site consists of the area in Figure 2 identified as the Hedblum
Industries Plant, as well as adjacent areas where contaminated
groundwater is presently located or was, at one time, located. The
site includes approximately ten acres area designated as an industrial
park. The site also includes an adjacent subdivision where
contaminated groundwater is presently located or was, at one tine,
located, and the swampy area adjacenthat to the bayou. The Plant has
open access as there are no fences or markings to distinguish the
property boundaries. The Plant is bordered on the east by the Detroit
and Mackinaw Railroad tracks, which are used 2-3 times per week. There
are scattered residences around the site, with most of them in the
AuSable Heights subdivision, located to the east and northeast.
The geology of the site area is characterized by glacial deposits of
two distinct units: clay and overlying sand and gravel. The sand and
gravel deposits were found to range between 45 and 50 feet in depth at
the site and the subdivision. The clay unit is believed to be at least
20 feet thick at the site. The hydraulic connection between the
bedrock and the sand and gravel unit is considered insignificant.
Groundwater flows in a northeasterly direction from the Plant, through
the subdivision and toward a bayou to the east of the subdivision.
This bayou empties into the AuSable River. The aquifer is estimated to
flow at a rate of 12.5 feet per day.
II. SITE HE?irav Map aflCR
The Plant was owned by Dasco Products from 1958 to 1985, during which
time it leased the property to several industrial firms that
manufactured various parts for the automotive industry. In September
1985, the title to the property was transferred to Aircraft Tool Supply
(ATS) , the current owner.
The site first cane to the attention of regulatory agencies during a
1972 Michigan Department of Natural Resources (MCNR) inspection which
noted that the Thomson Corporation, which operated at the site from
1968 to 1972, was discharging cooling and rinse water onto the ground.
The plant manager informed the MCNR inspectors that waste
trichloroethylene (TCE) was routinely dumped from a loading dock on the
northwest side of the building onto the ground from 1968 to 1972. An
estimated 4,000 gallons of TCE was rHqpoBPri of in this manner.
-------
: ; W*
AT. rot tjt T jljjf
•~ i T .•; 1- - '
.1 'HwT
-------
Hedblum
Industries
Plant
AuSabfe Heights Subdtvtelon
SITE LOCATION
FIGURE 2
-------
-4-
Begiming in 1973, volatile organic compounds (TOCs), primarily TCE,
were detected in residential walls to the east and northeast of the
plant in the AuSable Heights subdivision. In 1973, residential well
sampling revealed contamination at two locations, one with 10.0 mg/1
and the other with 1.0 mg/1 TCE. The more contaminated well was
replaced with a dapper well which showed no detectable TCE. In 1975,
two more wells became contaminated. Again, the more contaminated well
was replaced with a deeper one.
In 1976, a groundwater study commissioned by Amtel, Inc., which
purchased Thomson Corporation in 1974, concluded that the groundwater
contamination in the area was attributable to the dumping of TCE at
•the plant.
In 1977, contamination was found in the water supply wells at the site
and in the cooling water discharged to the ground. Also, the deeper
residential replacement wells and three additional residential wells
showed traces of contamination. Subsequently, the Osccda Township
Municipal Supply System was extended to residents through the
installation of a new water main. At the time, 69 out of 90 residents
were connected to the system. (Presently, 80 of the 90 residents are
connected.)
Samples taken during a 1980 plant inspection trip revealed that an
underground storage tank at the site contained TCE; 1,1,1-
trichloroethane (TCA); and, tetrachloroethylene (PCE). This tank was
excavated and eventually removed from the site. In May 1981, the MENR
constructed seven shallow monitoring wells (each well a maximum of 25
feet total depth) on and adjacent to the site. Soil samples taken
during the well installation revealed the presence of TCE and PCE.
Water samples taken contained TCE, PCE, TCA, and chloroform. The
water levels indicated a northeasterly direction of groundwater
movement toward the subdivision.
In 1982, the Hedblum Industries site was placed on the National
Priorities List. After offering the Potentially Responsible Parties
the opportunity to perform a Remedial Investigation/Feasibility Study
(RI/FS), the U.S. Environmental Protection Agency (U.S. EPA) assigned
the site to Camp Dresser & McKee, Inc., a U.S. EPA remedial
contractor, in 1986 via contract number 68-01-6939 to perform the
work. The RI was conducted from January 1987 through August 1987 and
included topographical and geophysical surveys; sampling of soils,
surface water, and sediments; installation of monitoring wells; and,
sampling of groundwater from monitoring, residential, and municipal
wells. The FS, completed in May 1989, developed and evaluated several
alternatives for addressing contamination problems at the Hedblum
Industries site.
-------
-5-
Historically, public interest with the Hedblum Industries site has
fluctuated. Hie 1973 discovery of TCE contamination of private wells
resulted in nuch connunity interest. At the time, the source of the
contamination was not known. After deeper replacement wells were
installed to provide an alternate water supply, cannjnity concern
subsided. Then, in 1977, when these replacement wells were also found
to be contaminated, public interest increased greatly. In August
1977, the AuSable Township Board sponsored a occraunity meeting to
notify residents of the contamination problem. The meeting was well
attended, as the MCNR and local health officials explained the problem
and reccranended that the Osooda Township municipal water supply system
be extended to serve the AuSable Heights subdivision. Most residents
were in favor of the proposal. However, some objected to the cost of
connecting to the system. By the end of 1978, the Oscoda Township
water supply system was extended and sixty-nine cut of ninety houses
connected. Subsequently, more residences have hooked up though there
are still 10 residences which rely on private wells for water. After
the municipal water supply was extended to the subdivision, public
interest once again diminished. Local officials have received very
few inquiries regarding the TCE contamination since then.
As part of the oomnunity relations program, two information
repositories have been established near the site, one at the AuSable
Township Hall and the other at the Oscoda Public Library. The work
plan, ccnnunity relations plan, fact sheets, RI and FS reports,
proposed plan, responsiveness summary, and any other site-related
materials that make up the administrative record have been placed in
the repositories.
U.S. EPA notified the local umtmnity, by way of the Proposed Plan, of
the preferred remedial alternative for the Hedblum Industries site.
To encourage public participation in the selection of a remedial
alternative, U.S. EPA scheduled a public cement period fron July 24
to August 23, 1989. In addition, U.S. EPA held a public meeting on
August 10, 1989, to Hicr^iag the Proposed Plan. U.S. EPA's responses
to ocnments received during the public meeting and to written cements
received during the public ocnment period, including cements that
were submitted on September 6, 1989 with U.S. EPA's approval, are
included in the Responsiveness Summary.
IV. SCOPE OF RESPONSE ACTION
The selected remedy for the Hedblum Industries site addresses the
contaminated groundwater and the associated public health risks from
ingesticn of the groundwater and inhalation of vapors. Groundwater
treatment will be utilized to reduce the levels of VOCs in the aquifer
under the AuSable Heights subdivision by pumping and treating the
contaminated groundwater.
-------
-6-
The r«Mdy also calls for additional soils investigation work to be
performed during the pre-design stage in order to verify the extent and
magnitude of soil contamination. The remedial investigation included
sane soils testing which revealed relatively low levels of subsurface
contamination at 15 to 40 foot depth. At the present time, a "no
action" remedy has been selected for the subsurface soil. If the
additional investigation reveals soil contamination that poses a public
health risk, this record of decision will be amended to include
subsurface soil remediation.
v. srns
The RI, consisting of en-site scientific studies and laboratory
analyses to determine the nature and extent of contamination at the
site, has been completed. RI activities were conducted from January
1987 to August 1987 and included the installation of monitoring wells,
and the sampling of groundwater, soils, surface water, and sediments.
The 1985 populations of Osccda and AuSable Townships were 11,386 and
2,380, respectively. The population within one half mile radius of the
Hedblum Industries site is estimated to be between 300 and 500 persons.
The results of the RI are summarized below.
Groundwater
Underlying the Hedblum Industries site and the surrounding area are
glacio-lacustrine deposits 200 to 300 feet thick, which overlie bedrock
formations of shale, sandstone, and limestone. Specifically, in the
study area, glacial deposits consist of two distinct units: clay and
overlying sand and gravel. The sand and gravel deposits were found to
range from 45 to 50 feet in depth at the site and the adjoining
subdivision. The clay unit is believed to be at least 20 feet thick at
the site. The hydraulic connection between the bedrock and the sand
and gravel unit is considered insignificant. The aquifer of concern is
the unconfined sand and gravel unit. Groundwater flows in a
northeasterly direction from the site, through the subdivision and
toward a bayou to the east of the subdivision. This bayou empties
into the AuSable River which in turn flows into Lake Huron (See Figure
2) . The velocity of the groundwater is estimated to be 12.5 feet per
day. Several residences down-gradient of the site still have private
wells tapped into this sand and gravel formation.
As part of the investigation, 11 groundwater monitoring wells were
installed at the site, W-8 through M4-18 (see Figure 3) . These wells
include 5 well-nests and one single background well. The deep wells
were screened in the lowest 10 feet of the aquifer, while the screened
interval of the shallow wells varied based on organic vapor analyzer
results but are generally in the upper 10 feet of the aquifer. These
wells complement 7 groundwater monitoring wells installed in 1981 by
the MENR.
Grcundwater samples were taken from the 18 monitoring wells, 5 Osccda
city wells and various residential wells, in two separate sampling
-------
MONITORING WELL LOCATIONS
FIGURE 3
-------
-8-
roundB in March/April 1987 and in July 1987. Parameters included full
organics and inorganics, including filtered and unfiltered metals and
cyanide, total dissolved and total suspended solids. In addition,
samples were analyzed for amnonia, nitrate, and nitrite to determine if
nearby septic systens had impacted the groundwater. Also, field
measurements of pH, specific conductanoe, and temperature were taken
and recorded in the field log book.
Some heavy metals were detected at concentrations exceeding drinking
water standards in the groundwater samples from both on-site and off-
.site monitoring wells. Elevated levels of lead and zinc were found in
on-site MCNR monitoring wells. Elevated levels of antimony, manganese,
and mercury were found in monitoring wells to the northeast of the
site. Arsenic and chromium, previously found during the MENR's study,
were not detected during this investigation of the site.
The presence of high concentrations of lead and zinc in the MENR wells
is probably due to well construction. There is no evidence that any
inorganic contamination found in the groundwater at or near the site
is attributable to site activities.
Nitrates, nitrites, and anracnia from septic systems do not appear to
have an adverse impact on the groundwater. The sandy soils in the site
area would not be expected to provide organic carbon or nutrients for
biodegradation of organic compounds to occur. However, the septic
systems do *rT«v*r t° be providing a nutrient source and a reducing
environment.
VDC contamination in the groundwater, primarily TCE and TCA, is present
at the site and the AuSable Heights subdivision. These concentrations
range from low parts per billion (ppb) to 4880 ppb and 3080 ppb for TCE
and TCA, respectively. The U.S. EPA primary drinking water standards
for these compounds are 5 ppb for TCE and 200 ppb for TCA.
Groundwater contamination was found at the site just east of the plant
and in the eastern section of the AuSable Heights subdivision.
However, the residential wells sampled between these two areas did not
show any contamination. Also, the contaminant concentrations in the
subdivision are higher than those at the site. This information does
not suggest that the subsurface contamination at the site is an on-
going source responsible for the groundwater contamination presently
found under the subdivision. Figure 4 shows the spacial distribution
of the groundwater contamination plume.
Groundwater sampling results at the subdivision indicate that moderate
levels of VDC, 4880 ppb TCE and 3080 ppb TCA, have persisted over a
time period inconsistent with sinple transport of a slug of dissolved
contaminants. If solvents dumped at the site entered solution and were
-------
OflCXtOWATER COKTAMNATON PLIAC
HED8LLM NDUSTRCS STTE
FIGURE 4
O O- 10
O 1O- 100
0 10O-IOOO
• > IOOO
-------
-10-
carried with the groundwater at a velocity of 12.5 feet per day, they
would have traveled to, or below, the bayou in less than 100 days, if
solvent dumping was stopped in 1972, all VDC contamination should
theoretically have paaood through the study area. Adsorption and
desorption processes should not have significantly slowed the
contamination pluae migration. All evidence suggests that the aquifer
contains very little organic carbon, which is the primary factor in
causing adsorption of organic compounds to the soil.
There are two possible explanations of the observed distribution of
groundwater contamination and its persistence in the site area. One
explanation is that clay lenses may be present in the aquifer, which
contain higher organic carbon content. These clay lenses would adsorb
organic contaminants and act as a physical barrier to VDC solute
migration. VOCs could form small pools in localized clay lense
depressions in relatively high concentrations and slowly re-dissolve in
the groundwater or could be flushed by the clay barrier. This would
account for the moderate levels of contamination on the eastern side of
the subdivision.
Another explanation is that VOCs at the leading edge of the contaminant
plume may have diffused out of active pore spaces into dead (inactive
or unused) pore spaces in the aquifer. Solutes in the dead pore
spaces, which are thought to comprise one-quarter to one-third of the
total pore space in the aquifer, are essentially trapped and would not
move with the groundwater. Once the contaminant plume has moved
through the aquifer, the trapped solutes in the dead pore space would
slowly move back into the active pore space along a concentration
gradient.
Soil
Subsurface soil samples were taken with a power auger at 8 locations
from depths of 2, 5, and 10 feet (See Figure 5). Also, split spoon
soil samples were taken to depths of approximately 50 feet during the
installation of deep monitoring wells (See Figure 6). A total of 56
soil samples were collected and analyzed. Since no regulated chemical
criteria exists for soils, the analytical results were compared to
background concentrations. There does not appear to be any inorganic
contamination resulting from the site activities, as the sample results
were within expected ranges when compared to background values.
Samples from SL07 and SL08, which were taken to confirm findings from
the 1981 MENR study showing total chromium and arsenic, did not show
inorganics exceeding normal concentrations.
Low levels of TCE and PCE were detected in en-site soil samples taken
near the old loading dock (SL01). Also, low levels of TCE, PCE, and
TCA were found in the vicinity of the former buried storage tank (SL04
-------
OLD u.s. aa
HEOBLUM INDUSTRIES SITE
POWER-AUGER SOIL SAMPLES
FIGURE 5
-------
MONITORING WELL LOCATIONS
SPLIT-SPOON SOIL SAMPLING
rIGURE 6
-------
-13-
and SL05). Most split apocn samples taken shewed no or only low levels
(low ppb) of WC contamination. Oily 1*108, placed near the former
underground storage tank location, showed appreciable VOC
contamination. In this boring, TCE contamination was found between 15
and 50 feet. The highest concentration was 11 parts per million (ppn)
at 20 feet.
Figure 7 shows surface water features in the Hedblum Industries area.
Because of the sandy soils, transport of contaminants from the site is
largely through the groundwater system. Discharge of grourdwater is to
nearby surface waters. The AuSable River Bayou is believed to be the
primary discharge point for the contaminated groundwater.
A total of four surface water samples were collected from the AuSable
River Bayou, three samples were taken downgradient of the site and one
up-gradient as a background sample. Analytical parameters included
full inorganics including filtered and unfiltared metals and cyanide,
full organics, total dissolved and total suspended solids and
nitrate/nitrite. Field parameters tested included pH and temperature,
which were recorded in the field sampling log book.
TCE appears to be discharging into the bayou. Surface water sanples
SW02 and SW03 show TCE, vinyl chloride, and trans-1,2 dichloroethylene
in the low ppb range. The latter two ccrpounds are suspected
biodegradation products. Vinyl chloride, especially, can be found
associated with TCE in reducing environments such as the swampy area of
the bayou where the samples were taken.
Inorganics in the surface water are not a problem, as the sample
results are within expected ranges when compared with background
concentrations.
Four sediment samples were collected at the same locations where
surface water samples were taken (See Figure 7). Two of the sediment
samples were grab samples and two were composites taken across the
width of the bayou. Analytical parameters included full organic and
inorganic priority pollutant scan. Neither organics nor inorganics in
the sediment are a problem.
IV. SCMJARY OF SITE RIS*
As part of the RI/FS, a public healtVervironmental risk assessment was
conducted that addressed the potential impacts to human health or the
environment associated with the Hedblum Industries site in the absence
of remedial action. This assessment follows U.S. EPA guidance for risk
assessment in general and for Super-fund sites in particular as
-------
SURFACE WATER * SEDIMENT SAMPLE LOCATIONS
swoi/300i«SAMPLE NO i LOCATION
FIGURF 7
-------
-15-
in: Guidelines for Estimating Exposures, Fed. Rag. 51:
34042 - 34054; Guidelines for Carcinogen Risk Assessment, Fed. Reg. 51:
33992 - 34003; Guidelines for the Health Risk Assessment of Chemical
Mixtures, Fed. Reg. 51: 34014 - 34023; and, Superfund Public Health
Evaluation Manual, EPA 540 1-86-060.
The purpose of identifying chemicals of potential concern is to ensure
that only those chemicals that are attributable to the site and that
are likely to contribute to risk are carried through the risk
assessment. However, since under U.S. EPA guidance, the toxic effect
of chemicals nay be considered additive, a conservative approach was
adopted which retains chemicals for evaluation if there is not clear
evidence of their lack of association with the site. Tables 1 through
5 list the chemicals of potential concern by media: groundwater
(sampling rounds 1 and 2), soil, surface water and sediment. These
tables identify the frequency of detection, the detected
concentrations (mean and maximum), and background levels.
The chemicals of potential concern have been evaluated to determine the
level of risk they pose to public health and the environment.
Groundwater provides different potential routes of exposure. The
primary one is the ingestion of groundwater, as there are residential
wells downgradient of the Hedblum Industries site. Additionally,
inhalation and Apr**] exposures to contaminants may occur through daily
use of water for activities such as cooking, bathing, showering, and
washing of rfi«>>«*« and clothes. Exposure pathways considered to have a
low potential for substantial exposure include: direct contact and
inhalation from watering lawns, gardens, or washing cars as the
exposure is periodic and of short duration; and, uptake by vegetables
with subsequent ingestion by humans, as contaminants are expected to
volatilize during sprinkling and soil ana null at ion will be minimal.
Potential routes of exposure through the soils include direct contact
with rfoi-ina] absorption and incidental ingestion. Not only are workers
at the plant on site potential receptors but trespassers also, since
the site is not fenced. More soil investigation needs to be conducted
to better determine the contamination concentrations.
Air exposures can occur through the inhalation of dust or vapors.
Exposure of on-site workers and trespassers is not considered
significant because the coarse grained soil at the site will not easily
be entrained by the wind, and air monitoring during RI activities did
not detect organic vapor during non-intrusive activities. There is
potential exposure of residents to air contaminants from groundwater
seeps on the banks of the bayou downgradient from the site.
-------
T&HTF i - Chemicals of
ORGANIC
Methylene Chloride
Acetone .
1,1-Dichloroethene
1,1-Dichloroethane
Trans-1,2-Dichloroethene
1,1,1-Trichlorethane
Carbon Tetrachloride
Tri chloroethene
Te trachl oroethene
Toluene
Xylenes
Bis (2-Ethylhexyl) ttithalate
INORGANIC (filtered)
Aluminum
Lead
Mercury
Zinc
INORGANIC funfiltered)
Aluminum
Iron
Zinc
*xenuai tenet
regueiicy of
2/32
1/32
1/32
3/32
s 1/32
5/32
V32
16/32
5/32
4/32
4/32
ite 17/32
12/32
13/32
2/32
21/32
8/20
20/20
12/20
tin in uroumBu
CLnukiiciataon
2.1
3.6
2.6
2.5
2.7
3.0
2.9
7.4
3.0
2.6
2.3
3.5
98.3
2.5
0.1
100
112
385
150
Sanple (Round 1)
6.7
104
14
20
16.5
3080
423
4880
58
125
50
14
400
381
3.9
24,870
862
13,100
24,300
Background
fug/1)
< 5
< 5
< 5
< 5
< 5
< 5
< 5
< 5
< 5
< 5
3
<200
< 1
<0.2
< 10
97
224
-------
THLE_2 - OsBcals of Mattel dram In OtuiWtEr Saples (RON) 2)
f Qmrt/atkr
Oetactw nan (igl) •« WD
Alcrin.r. • 14/23 151 2630
Lfiac 17/73 7.6 2P
Zlt. 23/23 ' 331 27.1T
JOWIC
e Chlorict 1/Z3 .2.4 330 < 5
3/23 9.3 OC 15TD
l,l-0ioilon«hene 1/23 2.R ^ < 5
l.lOicJiloroethane 1/23 2.^ 5.7 < 5
Trans-l,2-[)ichloroetriene 2yZ3 2.3 6.7 < 5
Oilorofom 1/23 - 0.13 < 5
1,1,1-TridilaToetnane 4/23 3.° 210G < 5
TricnloraeOrene 11/23 y»5 34171 < =
.asnasne 3/23 2.5 y < 5
Tetrachl jroetrene 3/23 2.3 13 < 5
Toluene 12/23 3.2 J. < 5
^-•-autvl =>TtrBlate 1/23 1.4 y < 2
Ss(2-ctnvlne(yl} =hrva1ate 4/23 2.° 1^ 4
-------
3 - Qabcals
-------
4 - Oartals of feterttol Qrcem in Srface tffcr Stofes
•M^»
Fmuncyof Qimtr*.kn
fc*)
ORGWIC
Vinyl Chloride 2/3 5.9 14 <10
Trans-1 ^-Oictilaraecriene 2/3 14.2 91 < 5
Trichlcrrsthene 2/3 '15.1 fi7 < 5
Fhttelate 3/3 4.4 5.3 4J
J-estiiata
T?a£5 - Chawcals of Fttntial Conosm in Ssttert Saoles
FfHjjency of Qit
Oancal DBtec±xn near (i^.) n» (u^.) (t^.)
3/3 75.3 250 129
Trans-1,2-3; chloroetrEre 1/3 2.9 4 < 5
Toluene 1/3 3.5 7 5.S
Pit^late .3/3 530 890 3Z7
-------
-20-
Surfao* %»ter and sediment exposure is ocnfined to the bayou.
Potential exposure is through A^-mal absorption and incidental
ingestion while swimming and oontaminant uptake via fish consumption.
For risk assessment purposes, individual pollutants are separated into
two categories of chemical toxicity depending on whether they exhibit
noncarcinogenic or carcinogenic effects.
Health criteria for chemicals exhibiting noncarcinogenic effects are
generally developed using reference docos (RfDs) developed by the
U.S. EPA RfD Work Group or RfDs obtained from Health Effects
Assessments. The RfD, expressed in units of ng/kg/day, is an estimate
of the daily exposure to the human population, including sensitive
subpopulations, that is likely to be without an appreciable risk of
deleterious effects during a lifetime.
Cancer potency factors, developed by the U.S. EPA's Carcinogen
Assessment Group for potentially carcinogenic chemicals, expressed in
units of (ing/kg/day)'1, are derived from the results of human
epidemiological studies or chronic animal bioassays.
Table 6 and 7 present the health effects criteria values for site -
related chemicals in the groundwater and surface water.
of
To quantitatively assess the potential risks to human health associated
with the current exposure scenarios, the concentrations of chemicals
present in relevant environmental media at potential exposure
concentrations are converted to chronic daily intakes (GDIs) . GDIs
are expressed as the amount of a substance taken into the body per unit
body weight, per unit time or mg/kg/day. For potential carcinogens,
excess lifetime cancer risks are obtained by multiplying the GDI by its
cancer potency factor. U.S. EPA has implemented actions under
Superfund which after remediation leave a total cancer risk ranging
from 1 x 10~4 to 1 x 10~7, i.e., the probability of one excess cancer
is one in 10,000 or 10,000,000, respectively, under the conditions of
exposure. A risk level of 1 x 10"^, representing a probability of one
in 1,000,000 people contracting cancer due to exposure to the potential
carcinogen, is used as a point of departure for establishing the
criteria for remediating a site.
Potential risks for noncarcinogens are presented as the ratio of the
GDI exposure to the RfD (GDI: RfD.) . The sum of all the ratios of
chemicals under consideration is called the hazard index. This
-------
TABLE 6
«AlTH EFFECTS CRITERIA f» ORAL EXPOSUSi TO CH£MICAL$ Of CONCE**
Cr*«>ca'
Aceton*
Eenjene
S:*i2-ethy 'heiyllcritna late
Caroon tetraciior >ae
Cn lorof or—
;.;-Cicri'oroetnane
i.i-D'criicroetriene
trans -1 ,2-Oicnloro«tri«ne
Ii-n-outyl ontrvalate
Hetfiy'ene cnlo-ice
Tetracn ieroetriy ie*e
Toluene
1 ; '. • t~ ~'f 'o'setnane
~ • :c*. 'e'oet ri«^e
viry: Cr.'i:-'ce
i, ie"es lime:.
8a-i.-"
Cay •-•
C ,f •. :e
'. rz~
Leac
Mg - c w * v
.-•-.c
Reference Oose
(Rfc;
1E-1
... *
2E-2
7E -t
1E-2
—
9E-3
1E-2
1E-1
6E-2
'.£-2
3E-1
9E-2
7 4£-3*
...
2
5E-2
5£-4*
2E-2
...
6E-4 (d)
2r -3
2E-1
Unce-:a •-•..•
fac:cr la:
l.OOC
i . :••::
: . sec
i.oc:
—
:.GOC
l.OOC
l.OCC
100
:.o:c
:oc
: . oo:
1 . OCC
—
:cc
"ix
iC
ICC
1000
iC
2 * *»
IRIS
IRiS
IRIS
;R:S
IRIS
is:s
HA
IR!S
IR.'S
ISIS
IRIS
IRiS
nA .
IRIS
;s:s
hA
is;s
—
...
ME A
M£ A
£»t/C*o Cance-
Pc:e-:y faetcr
(mc.»;;oa,)- :
...
2 9£-J
1 «E-2
1 3t • ;
6 1E-3
9 1E-2
0 £
...
...
7 5E-3
5.1E-2'
—
—
1 !E-2
2 3
...
...
—
—
—
—
—
...
*»« '• 0 - 1 C *
...
t
E?
B?
C ?
^
^
82
E2
—
—
82
A
...
...
C
B<
—
...
.t -.-ce-:« ••:.» 'actc-s u*ec ts Oeveloc reference doses consist c' mult isles of 10. ea:" factcr representing t ssec-'
a-ea c' uncertainty inherent m the data availa&le. The stan;arc uncertainty factors include
t 10-'elc 'act;' tc account for the variation in sensitivity among the oemoers o' tne nuinar. poou'atie-.
A i;-'eie fact:- te •csci.-n: for the uncertainty IP eitraooiat mg animal data tc the case o? nuwans.
' '.C-'clc fa:tc- tc account for uncertainty m eitraso ia:'ng from less than cnronic «OA£iS tc cnronic » ^rormenta'• erotec:'Cr
ice-:.. ;E*A; ;S£7 ««':* AOvisones (H»). Office o' D"n«mg wate'. w«snm;tar<. C C . «a-c" 3:. 1987.
;•; -£i > {-, '-onmerta 1 Protection Agency (EPA). 1988 June Quarterly uooate for H£A ane «i£C Chemicals
{-. "ormer-.a . Criteria ane Asscssmtnt Office. Cincinnati Ohio Ju'y 15. 1968
»«;--. s' *y-oe^ce c lass •'icat ion sche»«t fer carcinogens A---umjn Carcmogei. su"'cie": e«'oe^ce '?v iur.a-
e:-c«-4c lec •:*'• s'.uc-.es. 61--prooa6l* «uman Carcinogen, inritec e»'0eice f 'er ecifle^'clos^ca ; s:.c es a-c t:ez.i:
e- re"ce '-r- «r es. S2--*rsca3le "um*r Care mcce- --ases-ate e»ioence '~vr- ei'De^'c :.c; ica '• s:.c-es »•-
t:t-.t:t «v'Cfc* '-vr j-'m<: stuC>«s. C--?ess'C'e •%/«• 't-: "ege- '. isn tec evice-:* •* a-"rj's c ". •
-ffe-;e Z;jf 'c' '>eao is Da sec or th* oio Proscsec "',.'.
««*!•« p«-c -c
*-.(.< ite• >« a»a < Ufile
-------
TABLE 7
NCMTN EFFECTS C«ITE«M FOt IHIU1.ATIOM CJWOSUIE TO CMCMICALS Of CONCEtN
Che»ical
•eferenc* 6o*e
<«fO>
(aig/ig/day)
uncertainty
Factor (•}
IfO
Source (6)
EPA/CA6 Caret r
Potency 'actor
pnthalate
Caroo* tetrecnlono*
Chloroforn
1, 1-DieMoroethene
1, 1-DicMorp*tn*ne
trans- 1,2-Oichloroethene
Oi-n-txrtyl pnthelate
Mfhylene chloride
Tetrecriloroethylene
Toluene
1,1, l-Triehloroethane
Vinyl
(cued)
Aiunirun
Iron
1
3€-1
1E-4
100
1,000
1,000
1,000
N£A
MCA
MCA
1.2
3.JE-3*
4.6C-3
2.95C-1
6.1
12
12
12
II
C
12
(j) uncertainty factor* used to develoc reference dMM eontiit of •jltipte* of 10. e»eh factor repretenting «
• re* of ureert«inty imerent In th« dat« •vaitcbl*. The itOTdarti incertunty factort inelnle:
. A 10-fold factor to •ccotsit for the variation in i«r»itivtty ••one the MBOcrt of tfie ht/wn pocul«tior;
. A 10- fold factor to account for tKe tnctrtalnty In titrapetatlne aniMl data to the ea*e of hiMns;
. « 10- fold factor te account for uncertainty in extrapolating froM te«» than chronic *OAEi.i to cnronic «CAE.S;
•ne;
. A 10- fold factor te accoirtt for tne incertainty in eitrapolating fro* tCMELt to
Oo»e (B'8) Source:
ane NEE; ChemicaK. Envir
KIA • tr>viroi»intit Protaction Ae«rey . 1988.
tal Criteria and Aate*»a»nt Office. Cincinnati, OTiio.
Ouart«riy uea«te to<- *£»
July 15, 1908.
(c) weight e' evidence classification acftea* for carcinogenc A--Human Carcinogen, sufficient evidence from
eciow"oiosic«i studies; I1--*rooable Muwn Carcinogen, (iaited evidence fro* epioemotogicti studies and
evio*nce from eniMi studies; 12--Probable Hunan Carcinogen, inadequate evidence fro* epidmioiogicai stuC'es *ne
aoeouttr eviaence fro» aniaal studies; C--Po««fDle Nuaan Carcinogen, liaited evidence in aninwis in th« tott-ft c'
rttrier oita; 0--«ot Classified as to fttMtn carcinogenictty; and £--Evidenee of •oncarcinogenicity.
• « »evie» pending.
••• ' no criteria available.
-------
-23-
hazaxd index is useful as a reference point for gauging the potential
effects of environmental exposures to complex mixtures. In general,
hazard indices which are less than one are not likely to be associated
with any health risks. However, all hazard indices less than one
should not be categorically considered acceptable because of the
uncertainty associated with estimates of GDI and RfD.
In accordance with U.S. EPA guidelines for evaluating the potential
toxicity of complex mixtures, it is assumed that the toxic effects of
the site related chemicals are additive. The lifetime excess cancer
risks and the GDI: RfD ratios are q^rnoH for each exposure scenario to
indicate the potential risks associated with mixtures of potential
carcinogens and noncarcinogens, respectively. These risk estimates
are presented in Table 8 for ingest ion of grcundwater, Table 9 for
inhalation of volatile chemicals near the groundwater seeps, and Table
10 for dermal absorption and incidental ingestion of surface water.
The primary risks are associated with ingestion of volatile organics
in the groundwater as both average and plausible maxim im exposure
scenarios result in upperbcund lifetime excess cancer risks that
exceed 1 x 10"6. The plausible maximum scenario used to evaluate
exposure and risk via ingestion of fish from the bayou resulted in an
upperbcund lifetime excess cancer risk that exceeds 1 x 10"6.
However, the risk is likely to be overestimated based on the
bioconcentration factors used in estimating concentrations in fish,
assumptions made regarding the persistence of measured concentrations
year round and into the future, and the assumption that predicted
concentrations in fish are present at the tima of ingestion. It
should be noted that all of the estimates of risk to human health are
conservative, as they assume much more extensive contact with site
contaminants than is currently occurring. Thus, the exposure and
risks tend to be overestimated but are useful in determining whether
to take remedial action at the Hedblum Industries site.
VII. DESCRTPncN OP
Technologies to *
-------
TABLE 8
ESTIMATED EXPOSURE AMD USE ASSOCIATED WITH THE
tHCCSTIOi Of &OUNOWATEI: CUMENT LAND-USE
HCMLUPI INDUSTRIES SITE
CHRONIC DAILT
INTAKE (COD VIA .
INCEST ION
CHEMICALS OF
POTENTIAL CONCERN
POTENTIAL CARCINOGENS
Organic*
METHTLENE CHLORIDE
1,1-OICHLOROETHENE
1,1-OICHLOROETHANE
CHLOROFORM
CAR ION TETRACHLORIDE
TRICHLOROETNENE
IEN2ENE
TETRACMLOR06THENE
IISC2-ETHTLHEXTL) PNTNALATE
NON CARCINOGENS
Org«mcs
METHYLENE CHLORIDE
ACETONE
1,1-OICHLOROETMENE
TRANS- 1 ,2-DICHLOROETHEN£
1.1,1-TRICHLOROETHAME
CARBON TETRACMLORIDE
TETRACKLOROETNEiiE
TOLUENE
B:S(2-ET*'l.HEXTL ) PHTMALATE
ci-N-ii,'T»i PNTHALATE
ME R CUR?
.£*:
Inorganics (iTtf i I ttred)
:IN:
AVERAGE
PLAUSIBLE
MAXIMUM
COMBINED
ESTIMATED 6!
SC
TOXICITT PLAUSIBLE
CRITERIA AVERAGE MAXIMUM
CANCER
POTENCT
FACTOR UPPERBOUNC LIFETIME
(•B/kg/day)-1 EXCESS CWrCEl RISC
1.BOE-OS 9.436-03
2.206-05 9.14E-04
2.04E-05 5.71E-04
3.71E-06
2.20E-05 1.21E-02
4.5n-05 1.39E-01
2.04E-05 8.00E-04
2.20E-OS 1.66E-03
2.61E-05 4.576-04
6.2* -05 9.43E-03
1.51E-04 1.72E-02
7.71E-05 9.14E-04
7. HE-OS 4.71E-04
6. 864-05 3.71E-06
9.43E-OS a.BOE-02
7.71E-05 1.21E-02
1.60E-04 1.39E-01
7.71E-OS 1.666-03
8.00E-05 3.S7E-03
6.866-0) 1.43E-03
9.14E-OS 4. 576-04
8. 296-05 1.31E-03
3.48E-06 1.11E-04
4.73E-03 7.74E-01
1.14E-CU 1.09E-02
TOTAL (org«r>ics »r
-------
TABLE 9
ESTIMATED EXPOSURE AMD tISt ASSOCIATED WITH EXPOSURE 0' CUttEMT RESIDENTS
TO CO* T AM IN A* TS VOLATILIZED 'ROM TNE GROUK0WATER SEEP
CURRENT LANO-USE/HEDBLU" INDUSTRIES. MICHIGAN
CHRONIC OAILT
UTAtE (COD VIA
INHALATION
AVERAGE
PLAUSIBLE
MAXIMUM
TOXICSTT
CRITERIA
COMBINED
EST1HATEC RISi
AVERAGE
PLAUSIBLE
MAX ; •«.•»
PCTExTIAL CARCINOGENS
VlNH
TRICH'.OROCTHENt
3.70E-07
I.UE-Oc
3.9M-06
1.23E-05
CANCER
POTENCT
FACTOR
(mg/kg/d*y)-1
2.95E-01
4.6E-OJ
TOTAL :
OPPEtBOUNC
EXCESS CANCER RISK
U-07
5E-09
1E-07
1E-06
6E-CE
U-06
1 ,2-OICM|.C*OeTMENE
4. 16E-06
4.0CE-06
3.96E-10
1.28E-C5
1.23E-05
1.22E-09
REFERENCE
DOSE (RtD)
2.0E-02 (•)
7.4E-03 (•)
l.OE-01 (§)
TOTAL:
2E-04
JE-04
4E-09
6E-C-
2E-C3
IE-OS
2E-C3
(*; ic cjr
-------
TABLE 10
ESTIMATED EXPOSURE AMD RIST ASSOCIATED WITH EXPOSURE Of SWIMMERS 11 TNE IATCU
10 CONTAMINATED SURFACE WATER
TNtQUCN DEIMl ABSORPTION AMD INCIDENTAL INGEST ION
CUtlEMT lAMD-USE/NEDBLUM INDUSTRIES. MICHIGAN
CHRONIC DAILY
INTAKE (COI) VIA
DERMAL ABSORPTION
(•g/kg/day)
CHEMICAL
POTENTIAL CARCINOGENS
Organic!
VINTL CHLORIDE
TRICMLOROETHENE
MONCARCINOCENS
Organics
rtAWS- 1.2-DICNLOROETNENE
rRICHlOROETHfHE
AVERAGE
8.S6E-10
3.23E-09
3.23E-08
6.34E-07
PLAUSIBLE
MAXIMUM
1.67E-08
1.3AE-07
1.64E-06
1.ME-06
7.35E-06
CHROMIC DAILY
INTAKE (CDI) VIA
INCIDENTAL INCEST ION
(«g/kg/d«y)
AVERAGE
2.06E-08
4.52E-08
4.23E-07
4.52E-07
1.31E-07
PLAUSIBLE
MAXIMUM
1.67E-07
8.01E-07
1.09E-05
8.0U-06
6.34E-07
TOXICITT
CRITERIA
CANCER
POTENCY
FACTOR
(*9/kg/day]
2.3
1.1E-02
REFERENCE
DOSE (RfD)
(*9/kg/d«y]
1.0E-02
7.4E-03
1.0E-01
COH8IHED
Si
AVEStCE H*«i
UPPER80UWO i |(fi
1- ' E«CESS CAHCEB »:
5E-OS
56-10
TOTAL SE-Ofl
1 CDI:»fC
Sf-CS ^*
7E-OS ^H
Kf-Oi ^B
H
-E
1
TOTAL TE-04
3E
-------
-27-
Alterrwtive 1 - Sito Ifcwutorirn
Capital Cost: $ 60,400
Annual O6M Cost: $ 6,000
Total Present Worth Cost: $132,400
Alternative 1 provides for the continued monitoring of oonditicns at
the site. No action to remediate contamination in any of the media is
included. This alternative involves: 1) abandoning six of seven MENR
monitoring wells currently located at the site (saving the triple well
nest near the northeast corner of the plant for continued monitoring) ;
2) installing one additional well nest at the southeast corner of the
subdivision to monitor for contaminant plume migration in this
direction; 3) performing quarterly groundwater monitoring for the first
year and semi-annually thereafter for an additional 29 years; 4)
performing additional monitoring of subsurface soils at the site in
both the saturated and unsaturated zones to further define the
magnitude and extent of contamination; and, 5) performing a site
evaluation every five years for a 30 year period to determine if site
conditions are changing and if so, evaluate what actions are needed to
address these changes.
Alternative 2 ~ Ouig^*?t t*> Qarrrfa Vfat^*r Ifain
Capital Cost: $ 98,300
Annual O&M Cost: $ 6,000
Total resent Worth Cost: $170,000
Time to Implement: 1-2 months
Alternative 2 provides the residents in the subdivision, currently
using groundwater as their potable water supply, with an uncontaminated
source of potable water. Because no action will be taken to remediate
contamination, continued site monitoring will be required. This
alternative involves: 1) connecting all residents in affected areas
of AuSable Heights subdivision (along Franklin and River Roads), who
are not currently connected, to the Qscoda municipal water main; 2)
abandoning six of seven MENR monitoring wells on the site (saving the
triple well nest near the northeast corner of the plant for continued
monitoring); 3) installing one additional well nest at the southeast
corner of the subdivision to monitor for contaminant plume migration in
this direction; 4) performing quarterly monitoring of groundwater
quality the first year and send-annually thereafter for 29 additional
years; 5) performing additional subsurface soils investigation to
further define the magnitude and extent of contamination; and, 6)
performing a site evaluation every five years for a period of 30 years
to determine if the site conditions change and if so, evaluate what
actions are needed to address these changes.
-------
-28-
Capital Cost: $ 434,000
Annual O&M Cost $ 264,000
Total Present Worth cost: $1,379,000
Tine to Implement: 4-5 years
Alternative 3 treats contaminated groundwater in the aquifer under the
site to reduoe the levels of volatile organic compounds (MXs) . This
alternative includes: 1) installing an extraction well system in the
AuSable Heights subdivision and an extraction veil on the site property
downgradient of the plant; 2) pumping extracted water to the site for
treatment to MCTfi using activated carbon; 3) discharging effluent water
from the treatment process to the bayou; 4) monitoring groundwater at
the subdivision during the treatment process; 5) abandoning six of
seven MDNR monitoring wells on the site (saving the triple well nest
near the northeast corner of the plant for continued monitoring) ; and,
6) performing additional monitoring of subsurface soil at the site in
both the saturated and unsaturated zones to further define the
magnitude and extent of contamination.
AlteTnative 4 — Expavat"^ and Treat
Capital Cost: $652,800
Annual O&M Cost: $ 6,000
Total Present Worth Cost: $724,800
Time to Implement: 3-6 months
Alternative 4 excavates and treats contaminated subsurface soils
located on-site using a mobile on-site thermal volatilization treatment
system. Because contaminated groundwater will be left in the aquifer,
continued monitoring will be required. This alternative involves: 1)
excavating contaminated subsurface soils on-site to an approximate
depth of 35 feet using conventional excavation techniques; 2) treating
contaminated soils on site with a thermal volatilization treatment
system and backfilling the excavated pit with treated soils; 3)
treating groundwater pumped from the pit during excavation on site with
activated carbon and discharging to the bayou; 4) abandoning six of
seven MDNR monitoring wells on site (saving the triple well nest near
the northeast corner of the plant) ; 5) installing one additional well
nest at the southeast corner of the subdivision to monitor for
contaminant plume migration in this direction; 6) performing quarterly
monitoring of groundwater quality in the aquifer the first year and
semi -annually thereafter for an additional 29 years; 7) performing
additional monitoring subsurface soils at the site in the unsaturated
zone to further define the magnitude and extent of contamination; and
8) performing a site evaluation every five years for a period of 30
years.
-------
-29-
t Contaminated
a
Capital Cost: $ 969,000
Annual O&M Cost: $ 264,000
Total Present Worth Cost: $1,914,200
Time to Implement: 4-5 years
Alternative 5 includes actions to address the contaminated
grcundwater and ocntaminated soils. This alternative involves:
1) installing an extraction well system in the AuSable Heights
subdivision and an extraction well on the site dcwngradient from the
plant; 2) pumping extracted water to the site for treatment to the
Mds using activated carbon; 3) discharging effluent water frcn the
treatment process to the bayou; 4) monitoring groundwater quality at
the subdivision during the treatment process and quarterly for one
year after site closure; 5) abandoning six of seven MCNR monitoring
wells on site (saving the triple well nest the northeast corner of
the building) ; 6) excavating contaminated subsurface soils on site to
a depth of approximately 35 feet; 7) treating contaminated soils on
site using a thermal volatilization treatment unit and backfilling
the excavated pit with treated soils; 8) treating groundwater pumped
frcn the excavated pit using activated carbon; 9) performing
quarterly groundwater monitoring from eleven monitoring wells on
site and in the subdivision during the first year after site closure;
and, 10) monitoring subsurface soils at the site in the unsaturated
zone to further define the magnitude and extent of contamination.
Alternative 6 - _ No Action
Capital cost: $0
Annual O&M Cost: $0
Total Present Worth Cost: $0
Time to Implement: none
Alternative 6 is the no action alternative. Under this alternative,
no actions to remediate environmental contamination at the site or in
the subdivision will be performed. All monitoring and residential
wells will be left as is, no monitoring will be performed.
VIII. CnHPRRATIVE AMU"-V?>IS CF AT.TCTNATIVES
A detailed analysis was performed on the six alternatives using the
nine evaluation criteria in order to select a site remedy. The
following is a summary of the comparison of each alternative's
strength and weakness with respect to the nine evaluation criteria.
These nine criteria are: 1) overall protection of human health and
the environment, 2) compliance with applicable or relevant and
appropriate requirements (ARARs) , 3) short-term effectiveness, 4)
long-term effectiveness and
-------
-30-
5) cost, 6) reduction of toxicity, mobility and volume,
7) iaplementability, 8) State acceptance, and 9) community
and the
Evaluation of the overall protect! veness of each alternative focuses
en how the alternative achieves protection over time and how the
risks are eliminated, reduced and controlled through treatment,
engineering controls or institutional controls. Alternative 5,
which treats contamination in the groundwater and soils would provide
the highest degree of protection to the public health and the
environment. Raping and treating contaminated groundwater should
reduce the levels of VOC contamination in the aquifer to those
required by Michigan Act 399 of 1976. Excavating and treating
contaminated soils on site will remove this possible source of
groundwater contamination though exposure to this source was not
positively identified as a potential health risk in the public health
assessment. Alternative 3 treats the contaminated groundwater as in
Alternative 5, to levels required by Act 399 of 1976 and is
protective of public health and the environment. Alternative 4
treats the contaminated on-site soils but since the residential wells
directly east of the site do not show elevated levels of VOC and
indicate that the soils are not an on-going source of contamination,
this alternative will have minimal protective effect on human health.
Alternative 2 will eliminate ingestion of and incidental contact with
contaminated groundwater for those residents connected to the water
main but it does not treat contamination in the environment and
therefore is not protective of future well users or the environment.
Alternatives 1 and 6 are not protective of public health and the
environment because they do not treat contamination in the
environment.
Compliance with ARARs
Each alternative is evaluated for compliance with ARARs, including
chemical -specific, action-specific and location specific ARARs.
These ARARs are presented in Table 11 with the alternatives to which
they apply. All of the alternatives, except the no action
alternative, will meet their respective ARARs with the following
exception: Alternatives 1, 2, and 4 do not comply with the Safe
Drinking Water Act of 1987 and Act 399 of 1976 which set primary
drinking water standards.
Effect!
This evaluation focuses on the effects on human health and the
environment which aay occur while the alternative is being
implemented and until the remedial objectives are met. The following
-------
I ABIE 11
CONPUANCE UIIN APPLICABLE OR RELEVANT AHO
APPROPRIATE REQUIREMENTS
AT TNE HEDBILM IHDUSIRIES SHE
REGULATION. POLICT Ot LAW
APPLICABILITY
ALTERNATIVES
RESPONSE
Chemical-Specific ARARs
Safe Water Drinking Act
of 1987
Act 399 of 1976
(Safe Drinking Water Act)
Supplying potable
water
Potable water,
grounduater
Sets primary drinking
water standards
TCE Sppb
TCA 200 ppb
Establish MCLs for
drinking water in
Michigan
Action-Specific ARARs
federal Requirements
Clean Water Act
Regulates discharge
of water into rivers
State of Michigan has NA
jurisdiction over issuance
of NPOES permits
NA
NA
X: In compliance with ARAR
Nul in (ompllance with ARAR
NA Nut nppl M uliI P
-------
TAB1E 11 (Continued)
COMPLIANCE IIITN APPLICABLE OR RELEVANT ADD
APPROPRIATE REQUIREMENTS
AT THE NEDILUN INDUSTRIES SITE
REGULATION. POLICY OR LAW
APPLICANILIIT
RESPONSE
1 Z S 4 5 A
Resource Conservation and
Recovery Act (RCRA)
40 CFR 264.114
Closure of haiardous
waste facilities
Closure of hazardous
waste fac iIi t ies
Requires grounduater
monitoring after closure
Requires equipment to
be decontaminated or
disposed upon facility
closure
X NA NA X X
HA NA NA X X
State Requirements
Act 64 of 1979 Part 2
Contaminated soils
Requires identification
of haiardous wastes
X NA NA X X
Act 245 of 1929 Rule 57
Contaminated soils
Prohibits the presence
of toxic substances at
levels which may be
injurious to the public
health
NA NA X X X NA
-------
TAILE 11 (Continued)
'LIANCE WITH APPLICABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS
AT THE NEONLUN INDUSTRIES SITE
REGULATION. POLICY OR LAW
APPLICABILITY
RESPONSE
1 2 I 4 5 6
Act 245 Part 9
Act 315 of 1968
Act 368 of 1978
Contaminated
groundwater
Contaminated
water, potable
water supply
Haintain quaIity
groundwater in
usable aquifers,
defines the
requirements for
hydrogeologic study
and groundwater
moni tor ing
Requires proper
abandonment of all
groundwater moni-
toring wells
X X X X X
X X X X X
Act 245 Part 21
Requires NPDES
permit for waste
effluent into
waters of the
state
NA X X X X NA
Requires reporting
of wastewater
discharging into
waters of the state
NA X X X X NA
-------
IABIE 11 {Continued)
COMPLIANCE WITH APPLICABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS
AT THE HEOBLUN INDUSTRIES SITE
REGULATION. POUCT OR LAW
APPLICABILITY
RESPONSE
ALTERNATIVES
1 2 3456
Act 98 of 1913
(Waterworks and Sewerage
System Act)
Contaminated
groundwater and
soils treatment
Provides for
supervision and
control over
discharge of
industrial Iiquid
wastes
NA NA X X X NA
Act 399 of 1976
(Safe Drinking
Water Act)
Supplying potable
water
Establish MCLs for
organic chemicals
Act 348 of 1965
(Ihe Air Pollution)
Contaminated soils
on-site treatment
Controls emission
air contaminants to
safe levels,
requires air
monitoring
NA NA NA X X NA
Act 347 of 1972
(SoiI Erosion and
Sedimentation Act)
Contaminated soiIs
excavation and
treatment
Soil erosion
and sedimentation
NA NA NA X X NA
-------
TABLE 11 (Continued)
COMPLIANCE WITH APPLICABLE 0* RELEVANT AMD
APPROPRIATE REQUIREMENTS
AT THE HEDBLUM INOUSIRIES SITE
REGULATION, POLICY OR LAW
APPLICABILITY
RESPONSE
1 2 3 454.
Act 64 of
(The Hazardous Waste
Management Act)
Contaminated soils
and groundwater
treatment
Requires permits for
hazardous waste treatment,
storage or disposal
fac iIi t ies
NA NA NA X X NA
Incinerator Performance
Standards
NA NA NA X X NA
Act 345 of 1965
(Air Pollut ion Act)
Contaminated soils
Treatment
Requires permit
to construct
or relocate equipment
which may create air
poIlut ion
Specifies information
and data to be
included in application
for permit.
NA NA NA X X NA
NA NA NA X X NA
Act 345 of 1965
Mule 901
Contaminated
soils treatment
Controls emissions
of air contaminants
which may cause
injury to human health
and the environment or
proper t y
NA NA NA X X NA
-------
TABLE 11 (Continued)
COMPLIANCE WITN APPLICABLE Of RELEVANT
APPROPRIATE REQUIREN
AT THE HEDBLUN INDUSTRIES SITE
REGULATION. POLICY OR LAW
APPLICABILITY
RESPONSE
ALTERNATIVES
12345 6
loot i on-Spec i f ic ARARs
Act 203 of 1979
(The Goemaere-Andenon
Wetland Protection Act)
Act 346 of 1972
(Inland Lake* and Streams
Act of 1972)
Contaminated ground-
water and soils
treatment
Contaminated ground-
water and soiIs
treatment
Requires permit to con-
struct in a wetland.
Specifies technical
information for permit.
Requires permit to con-
struct surface water
discharge piping to
inland lakes and streams.
Specifies technical
information for permit.
NA NA X X X NA
MA NA X X X NA
1
X: In compliance with ARAR
•: Not in compliance with ARAR
NA: Not applicable
-------
-37-
factoxB were used to evaluate the short-term effectiveness of each
alternative: protection of the community during remedial actions,
protection of workers during remedial actions, environmental impacts
from implementation of alternatives, and tirnp until remedial
objectives are net.
With respect to protection of the community, Alternatives 1 through 5
will not pose risks to the local connunity, though there nay be
temporary inconveniences. Alternatives 4 and 5 which involve
excavation nay result in increased dust generation but this can be
controlled through conventional dust suppression techniques.
Risks to workers during remedial action in Alternatives 1 through 5
can be controlled with safe working practices. Alternatives 4 and 5
nay expose workers to VOCs from excavated soils but the levels should
be within applicable FELs and TLVs.
With respect to environmental impacts, Alternatives 1, 2, 3, and 6
will have continued migration of contaminated groundwater at the site
and under the subdivision as they do not address groundwater
contamination. Alternatives 3, 4, and 5 will result in a temporary
change in groundwater flow from extraction and pit dewatering and a
temporary increase in the flow rate in the bayou from the discharged
groundwater. Alternatives 4 and 5 could result in the release of low
levels of VDC to the air from the soils excavation.
Evaluation of the time until protection is achieved reveals the
following estimates: Alternative 2 should take a few weeks to a few
months, Alternative 4 should take 5-6 months, and Alternatives 3 and
5 should take 4-5 years. Alternatives 1 and 6 will not achieve
protection.
This evaluation focuses on the results of a remedial action in terms
of the risk remaining at the site after response objectives have been
met. The following factors are addressed for each alternative:
magnitude of regaining risk, adequacy and reliability of controls.
The primary risk identified at the site by the public
health/environmental risk assessment is from the ingestion of
contaminated groundwater. Alternatives 3 and 5 offer the greatest
degree of permanence as they minimize the risks from ingestion of and
incidental contact with contaminated groundwater by removing the
contaminants with treatment. Alternative 5 also treats subsurface
soils on-site. However, the soils were not found to pose an
unacceptable risk. Alternative 2 eliminates the risks from ingestion
and incidental contact with contaminated groundwater by supplying
-------
-38-
iidorts .connected to the water main with a clean source of potable
water. However, the contaminated groundwater would still persist
with this alternative. Alternative 4 reduces the risks from contact
with subsurface soils but also does not address the contamination of
the groundwater. Alternatives 1 and 6 will not mitigate any of the
risks presently associated with the site.
With respect to adequacy and reliability of controls, Alternatives 3
and 5 both use a reliable method to reduce and possibly eliminate
groundwater contamination. Total elimination of VOC contamination
will depend on its distribution in the aquifer. If the system
conponents mechanically fail, they may be replaced or repaired
without much ispact on the residences. The excavation and treatment
of on-site soils in Alternatives 4 and 5 should remove this possible
source of groundwater contamination. If the excavation or treatment
system mechanically fail, they may be replaced or repaired with no
exposure of the local oomunity to contaminants. Alternative 2 uses
connections to the water main to eliminate risks from groundwater
which has a low potential for failure.
This evaluation examines the estimated costs for implementing the
remedial alternatives. Capital and annual O&M costs are used to
calculate estimated present worth costs for each alternative.
Alternative 3, pimping and treating contaminated groundwater, has a
moderate capital cost and high annual cost which results in an
estimated present worth of $1,379,000. Alternative 4, excavating and
treating on-site soils has a high capital cost but since there is a
short implementation time, annual costs are low. This results in an
estinated present worth cost of $724,800. Alternative 5, which
combines Alternatives 3 and 4, has the highest capital and annual
cost. Estimated present worth costs total $1,914,000 for Alternative
5. The remaining 3 alternatives which provide less overall
protection of public health and the environment cost less than the
already mentioned alternatives. Alternative 6, no action, is
considered to have no associated costs. Alternative 1, continued
monitoring at the site and subdivision, has low capital and annual
costs. The estimated present worth costs is $132,400. Alternative
2, connecting affected residents to the Oscoda water main and site
monitoring, also has low capital and annual worth costs total
$170,250.
This evaluation addresses the statutory preference for selecting
remedial actions that enploy treatment, technologies which permanently
and significantly reduce toxicity, mobility, or volume of the
hazardous substances. This preference is satisfied when treatment is
-------
-39-
used to reduce the principal threats at a site through destruction of toxic
contaminants, irreversible reduction in contaminant mobility, or reduction
of total volume of contaminated media.
For Alternatives 3 and 5, the volume of contaminants in the groundwater
will be irreversibly reduced by extraction and treatment. The contaminant
plume mobility will be affected during treatment but any remaining residual
contamination will have the same mobility once pumping and treating has
stopped. Alternatives 4 and 5 will eliminate the toxicity, volume, and
mobility of contaminants in the soil. However, the en-site soil
contamination does not appear to be an on-going cause of groundwater
contamination under the subdivision. Each of these three alternatives will
treat some groundwater, extraction from the aquifer in Alternatives 3 and 5
and dewatering the excavation pit in Alternatives 4 and 5. The resulting
effluent water would meet discharge criteria and will be monitored to
verify this. The water treatment process will generate spent carbon that
may be considered hazardous waste and must be handled accordingly (by the
carbon supplier and regenerator). The other three alternatives, 1, 2, and
6, provide no treatment, and thus, do nothing to affect toxicity, mobility
or volume.
Tmpl ementabil ity
This evaluation addresses the technical and administrative feasibility of
implementing the alternatives and the availability of the various services
and materials required during its implementation.
Technically, the placement of the extraction well system in Alternatives 3
and 5 is dependent on the location of objects and structures in the
subdivision and the residents' willingness to have a well placed on their
property. Otherwise, the system can be readily constructed or leased and
operated. The excavation in Alternatives 4 and 5 can be accomplished with
conventional techniques but this may be difficult due to the close
proximity of the plant and the railroad trades. The treatment unit can be
easily constructed or leased and operated. For both the groundwater
extraction and the soil treatment, a pre-design study will be needed to
verify system performance. The connection to a water main in Alternative 2
is a common technology proven to be reliable. Alternative 1 only requires
installing a monitoring well and Alternative 6 has no actions.
Administratively, Alternative 2 will require tap-in fees to connect to the
Oscoda water main.
For all alternatives which include some type of action, all equipment,
services and specialists are available locally or from national vendors.
-------
-40-
State Acceptance
The Michigan Department of Natural Resources (MCNR) does not concur
with the U.S. EPA's selection of Alternative 3 as the preferred
remedial alternative for the.Hedblum Industries site as presented in
the next section. The MDNR agrees with the technology selected in
Alternative 3, but does not agree with the targeted cleanup level for
TCE. The MDNR wants a lower cleanup level for TCE, l ug/1, than that
indicated in the preferred reraedial alternative, 5 ug/1. Since the
groundwater will be cleaned so as not to exceed an excess risk level
of 1 x 10~* and the groundwater will meet all mavimmt contaminant
limits (MCLs), this remedy has been determined to be protective of
human health and the environment (see Reduction of Site Risks below).
Community response to the alternatives is presented in the
responsiveness sunmary which addresses comments received during the
public Garment period.
IX. SELECTED
Based upon consideration of the requirements of CERCLA, the detailed
evaluation of the alternatives, current information, and public
comments, the U.S. EPA has determined that Alternative 3: Punp and
Treat Contaminated Groundwater is the most appropriate remedy for the
Hedblum Industries site near Oscoda, Michigan. The major components
of this remedy include:
- Installation of an extraction well system in the AuSable Heights
subdivision (3 wells) and one extraction well on-site directly
downgradient of the plant. Each well will extract 150 gallons per
minute.
- The extracted groundwater will be pumped to the site and treated
using granular activated carbon adsorption. The effluent from
this treatment process will be analyzed to verify that it meets
discharge limits and will be discharged to the bayou. Groundwater
quality in the aquifer will be monitored during the treatment
process. Spent carbon will be handled as a hazardous waste by the
carbon supplier and regenerator.
- Additional subsurface soil monitoring will be performed on-site in
both the saturated and unsaturated zones to further define the
magnitude and extent of soil contamination and to determine if
there is a need for soil remediation.
-------
-41-
The selected remedy addresses the primary risk, ingestion of
contaminated groundwater, for the Hedblum Industries site as
identified in the public health/environnental risk assessment. The
selected remedy will pump and treat the contaminated groundwater
until the chemicals of potential concern have an additive
risk level of 1 x 1CT6. For those chemicals of potential concern
with established MQfi, as promulgated under the Safe Drinking Water
Act, these standards will be 'met at a mini man. The substanitve
requirements of the National Pollution Discharge Elimination System
(NPEES) will also be met by the discharged effluent to the bayou.
MCLs for the chemicals of concern are presented in Table 12. Those
affected residents with operating wells will have their wells
monitored and if it is found that these wells pose a threat to public
health at any time during the remediation, appropriate action will be
taken to supply the residents with an alternate supply of potable
water.
TABLE 12 — »fa vi mm Contaminant T.-im-itg for Chemicals of Potential Concern
Federal Primary Drinking Water
- Pinal KFL (UO/1)
Acetone -
Benzene 5
Bis (2-ethylhexyl) phthalate -
Carbon tetrachloride 5
Chloroform 100 (a)
Di-n-butyl phthalate -
1 , 1-Dichloroethane —
1 , 1-Dichloroethene 7
trans-l,2-Dichlorethene -
Methylene Chloride -
Tetrachloroethylene —
Ttoluene -
1,1, 1-Trichlorcethane 200
Trichloroethene 5
vinyl Chloride 2
Xylenes (total) —
Aluminum — —
Barium 1,000
Iron —
Lead 50 (5 proposed)
Mercury 2
Zinc -
— No Criteria
(a) The value of 100 ug/liter is for total trichalomethanes (i.e.,
the sum of chloroform, bttanochl oromethane , and bromoform) .
-------
-42-
The estimated capital exist for Alternative 3 is $434,000. Estimated
annual costs are $264,000, with a present worth of $1,001,000 (at 10%
over 5 years). Including in a salvage value for the equipment, the
estimated total present worth of Alternative 3 is $1,379,000. A
breakdown of these costs can be found in Table 13.
The remedial action selected for implementation at the Hedblum
Industries site satisfies the statutory requirements of OERCXA Section
121. The selected remedy protects public health and the environment,
attains ARARs, is cost effective, is a permanent solution, and reduces
the volume of wastes.
The selected remedy protects public health and the environment through
the use of activated carbon adsorption to treat contaminated
groundwater to levels required by Act 399 of 1976 of the Michigan Water
Resources Commission. The implementation of the remedy should not pose
any short-term risks that cannot be readily controlled nor any adverse
cross-media impacts. Residents with operable wells will be monitored
and appropriate action to supply an alternate source of potable water
will be taken in the event that contamination exists in their drinking
water at unacceptable levels.
With ARARS
The selected remedy of pumping and treating the contaminated
groundwater will attain ARARs. All potential ARARs for each of the
alternatives were presented in Table 11 in the Comparative Analysis of
the Alternatives section. The ARARs for the selected alternative are
presented below.
U.S. EPA will meet the substantive requirements for all ARARs that may
require permits. Permits will be secured for all activitites that are
determined to be off site. The procedural requirement of obtaining a
permit is not required for on-site activities pursuant to Section
121 (e) of CEKCLA.
FHERAL ARARS
Maximum Contaminant Levels established under the Safe Drinking Water
Act are ARARs at this site. MCLs are the navSimm contaminant
concentrations allowed in a regulated public water supply. These
levels apply at the point of distribution ("at the tap") to public
water systems having at least 15 service connections or regularly
serving at least 25 individuals. Levels are based on a chemical's
toxicity, treatability (including cost considerations) , and analytical
limits of detection.
-------
TABLE 13
ALTERATIVE 3
PUMP AND TREAT CONTAMINATED GBCUNDWATER
COST ESTIMATE
ITEM
Capital Costs:
Install 4 Extraction Wells $ 18,800
Install Header and Pipes to Site 36,400
Install Pipe from Site to Bayou 17,000
2 10 ft. Carbon Units 132,'oOQ
Initial Carbon (40,000 Ib.) 30,'oOO
Installation 10,'oOO
Construct Enclosure for Carbon Units 60,'000
Abandon 6 MDNR Monitoring Wells 3,'000
On-Site Soil Monitoring 26,'900
Contingency (15%) 50,'000
Engineering (15%) 50,000
TOTAL CAPITAL COSTS $434,000
Annual Costs:
Carbon Replacement $190,000
Labor . 2,'000
Monitoring and Sample Analyses (treatment effluent) 10,000
Maintenance 10,300
Enclosure Maintenance 6,'000
Punp Maintenance 5,'000
Groundwater Sampling 1,'200
Laboratory Sample Analyses 5,'000
Contingency (15%) 34,'OOP
TOTAL ANNUAL COSTS $264,000
Present Worth Analysis (10% over 5 years) $1,001,000
Salvage Value (56,000)
Total Present Worth $1,379,000
-------
-44-
MCLs are relevant and appropriate at Hedblum for groundwater protection
because the aquifers underneath the site and subdivision are considered
drinking water aquifers, and MCLs are the enforceable drinking water
standard for public water supplies. Since MOLs apply to water at the
point of use, these levels are appropriate for establishing water
quality in the drinking water aquifers at the site and the subdivision.
These standards will be applied to the groundwater itself to ensure
safe levels in the groundwater underneath the site and subdivision.
The CWA is an ARAR at this site since the treated groundwater will be
discharged to the surface water body (bayou) northeast of the site.
The AWQC are established for protection of freshwater aquatic
organisms. AWQC will be net at the point of groundwater discharge to
the bayou. Additionally, Section 404 of the CWA regulates construction
in a wetland. To the extent the swampy area and bayou are determined
to be a wetland, and to the extent the placement of the groundwater
intake and discharge pipes in the wetland is determined to be
construction, the appropriate substantive requirements of Section 404
will be met.
STKTE ARARs
Act 245 Part 4 P»i«* 57 prohibits the presence of toxic substances at
levels which may be injurious to the public health safety or welfare.
This rule establishes the procedure for developing allowable levels of
toxic substances in the surface waters of the State. The Rule 57(2)
Guidelines are utilized in making water-quality based permit
ranendations. The substantive requirements of these guidelines will
be met by the discharge to the bayou.
Act 245 Part 9 defines the requirements for hydrogeologic study and
groundwater monitoring. The substantive requirements will be complied
with when installing the groundwater monitoring wells.
Act 245 Part 21 requires an NPDES permit for waste effluent into the
waters of the State, and reporting of the wastewater discharge. The
substantive requirements of this Act will be met without
administratively acquiring a permit. CEPCIA section 121(e) exempts on-
site activities from obtaining permits. The purpose of this exemption
is to allow CERCXA response actions to proceed without the delays that
could result while waiting for other offices or agencies to issue a
permit.
-------
-45-
Act 315 Administrative Rules and Act 368 require that test wells be
permitted, constructed properly, recorded, and properly plugged upon
abandonment. These Acts are ARARs and the substantive requirements of
these Acts will be net.
C. Act 203 of 1979 (The Wetland Protection Act)
Act 203 requires a permit before construction can begin in a wetland.
The Act specifies the technical information that must be included
before the permit will be granted. The piping for the groundwater
system will be placed in the swampy area adjacent to the bayou. If the
placement of those pipes is considered construction, and the swampy
area is considered a wetland, the appropriate substantive requirements
of this Act will be met.
D. Act 346 Of 1972
This Act also requires a permit to construct surface water discharge
piping to inland lakes and streams. The substantive requirements of
this Act will be met.
E. Act 98 of 1913 Hhe Waterworks and Sewerage System Act)
Act 98 regulates the construction of industrial waste treatment plants.
To the extent that the groundwater treatment unit can be characterized
as such a treatment plant, the substantive requirements of the Act will
be met.
Oast Effective
The selected remedy is cost effective because it has been determined to
provide overall effectiveness proportional to its costs, the estimated
total present worth being $1,379,000. Alternative 3 and Alternative 5
provide the most permanent overall protection of public health and the
environment by treating contaminated groundwater and eliminating the
primary risk identified by the public hftal th/environmental risk
iirrrnmnfnf.. However, Alternative 5 includes soil remediation which
according to the presently available information and the risk
i i nrna nl does not pose an unacceptable risk (though additional soil
investigation will be conducted to verify the nature and extent of the
contamination). This soil remediation, which is presently deemed to be
unnecessary, costs an extra $535,000.
Utilization of
Srtliit-irn arvf Alt
The selected remedy has been determined to represent the maximum extent
practicable to which permanent solutions and treatment technologies
can be utilized. For the most part, each of the alternatives are
-------
easily ij*>lementable with no unusual short tern problems. Alternative
3 will reduce and possibly eliminate the groundwater contamination
depending on the distribution of VOC contamination in the aquifer.
Vtoereas, Alternative 2 and Alternative 5 also offer comparable degrees
of permanence, Alternative 2 does not offer protection of the
environment and Alternative 5 is not as cost effective as Alternative
3. Alternatives 1, 4, and 6 provide considerably less protection of
the environment than Alternative 3, as they do not remediate the
contaminated groundwater.
The statutory preference for remedies that employ treatment which
permanently and significantly reduces the tenacity, mobility or volume
of hazardous substances as a principal element is satisfied by
Alternative 3. The principal risk identified by the risk assessment is
the ingestion of and incidental contact with the contaminated
groundwater. The selected remedy extracts the groundwater and treats
it using activated carbon adsorption to reduce the toxicity and volume
Of hazardous
-------
VI
DCCBTKCBS SHE
The United States Environmental Protection Agency (U.S. EPA) has
reoently completed a Remedial Investigation/Feasibility Study (RI/FS)
regarding the Hedblum Industries site located near Oscoda, Michigan.
During the RI/FS, information was collected en the nature and extent of
contamination at Hedblum Industries and alternatives for appropriate
remedial action were developed 'and evaluated. At the conclusion of the
FS, a Proposed Plan was finalized by U.S. EPA which identified the
preferred remedial alternative for the Hedblum Industries site. U.S.
EPA held a public ojumaiL period from July 24 to August 23, 1989 for
interested parties to uuuutait on the U.S. EPA's May 1989 Feasibility
Study Report and the Proposed Plan. Oannents were also submitted on
September 6, 1989 with U.S. EPA's approval.
The purpose of this Responsiveness Summary is to document the conments
received during the public comment period and U.S. EPA's responses to
the comments. All of the comments suntnarized in this document were
considered prior to U.S. EPA's final decision.
SOMAFY OVERVIEW
The feasibility study identified and evaluated alternative remedial
actions for the Hedblum Industries site. Six detailed alternatives were
evaluated based on the nine criteria analysis as described in the
Decision Summary. Based upon this detailed evaluation, available
information, and public comments, the U.S. EPA has determined that the
most appropriate remedy for the Hedblum Industries site is Alternative
3: Pump and Treat Contaminated Groundwater.
The major components of the selected remedy include:
Installation of an extraction well system in the AuSable Heights
subdivision (3 wells) and one extraction well on-site directly
downgradient of the plant. Each well will extract 150 gallons per
minute.
The extracted groundwater will be pumped to the site and treated
using granular activated carbon adsorption. The effluent from this
treatment process will be analyzed to verify it meets discharge
limits and will be discharged to the bayou. Groundwater quality in
the aquifer will be monitored during the treatment process.
Affected operating residential wells will also be monitored and
appropriate action will be taken to supply an alternate source of
potable water in the event that contamination exists in the wells
at unacceptable levels. Spent carbon from the treatment process
will be handled as a hazardous waste by the carbon supplier and
rater.
-------
-2-
Additional subsurface soil investigation will be perfonnad on-site
in both the saturated and unsaturated zones to further define the
•agnitude and extent of soil contamination and to determine if
there is a need for soil remediation.
Historically, public interest with the Hedblum Industries site has
fluctuated. The 1973 discovery of TCE contamination of private wells
resulted in much coanunity interest. This concern subsided with the
replacement of contaminated wells with deeper wells which supplied an
alternate water supply. In 1977, these replacement wells also bee
.run
contaminated and ccmunity interest increased greatly. In August 1977,
the AuSable Ttwnship Board held a public meeting to inform the residents
about the contamination problem. At this well attended meeting, the
MENR and local health officials described the problem and reconnended
that the Oscoda Ttwnship municipal water supply system be extended to
serve the AuSable Heights subdivision. Most of the residents favored
the proposal. However, some objected to the cost of connecting to the
system. Presently, eighty of the ninety residences are connected to the
water system. After being supplied with a safe drinking water supply,
public interest once again diminished. Local officials have received
few inquiries regarding the TCE contamination since then.
As part of the ccmnunity relations program, two information repositories
have been established near the site, one at the AuSable Township Hall
and the other at the Oscoda Public Library. The administrative record
has been placed in the repositories for public review.
U.S. EPA notified the local conBunity, by way of the Proposed Plan, of
the preferred remedial alternative for the Hedblum Industries site. To
encourage public participation in the selection of a remedial
alternative, U.S. EPA scheduled a public eminent period from July 24 to
August 23, 1989. In addition, U.S. EPA held a public meeting on August
10, 1989, to discuss the Feasibility Study and the Proposed Plan. Four
people attended this meeting. Ocmnents received during the public
meeting and the public ccmnent period, including oomnents submitted on
September 6, 1989 with U.S. EPA's approval, are included in this
Responsiveness Sunnary, along with U.S. EPA's
-------
-3-
III.
Cbmnents raised during the Hedblun Industries public
summarized below*
it period
1.
North Central, Inc., at the direction of Amtel, Inc. (a
potentially responsible party); a local citizen; and, the Michigan
Department of Public Health would like to have the remaining residents
still using private wells in the AuSable Heights subdivision connected
to the xounicipal water system.
U.S. EPA'S RESPONSE;
U.S. EPA is confident that the public health will be protected through
the monitoring of the private wells that are still being used for
drinking water. To ensure that these wells are safe, U.S. EPA
Emergency Response personnel will be conducting residential well
sampling in October 1989. During the remediation at the Hedblum
Industries site, groundwater quality and movement will be monitored,
including these residential wells still in use. If at any time it is
revealed that there is a threat to the public health from the use of
these private wells, action will be taken to supply those affected
residences with an alternate supply of potable water.
The Michigan Department of Public Health is
red with the
potential hydraulic interference with the Qscoda Township municipal
water wells caused by the installation and operation of extraction
wells called for in the remedy,
U.S. EPA'S RESPONSE;
The actual design and placement of the extraction wells will take this
concern into account during the remedial design phase of the project.
3.
A local citizen is concerned about the H-jspn*ai of carbon front the
carbon adsorption process.
o.s.
'S
The spent carbon from the carbon adsorption water treatment process
will be handled as a hazardous waste by the carbon supplier and
regenerator. This spent carbon will be taken off of the site and
regenerated.
-------
-4-
4.
A local citizen had a oonoern about the discharge of phosphates or
other nutrients into the bayou through the water treatment process.
U.S. EEfr'S RKiKJGE:
It is not anticipated that through the carbon adsorption treatment of
the contaminated grounduater there would be the addition of phosphates
or other nutrients which would be discharged into the bayou.
5.
A local citizen was concerned about the contaminants in fish front the
bayou.
The Public Health/Environmental Risk Assessment, performed as part of
the Remedial Investigation, evaluated the potential exposure to local
residents of ingesting fish caught in the bayou. Under the average
case, it is assumed that 113 grams of fish are consumed once every two
weeks for seven months over a five year period. The total potential
lifetime excess cancer risk is below U.S. EPA's point of departure of
1 x 10~* for this average exposure scenario. Under the plausible
maximum case, it is assumed that 340 grams of fish are consumed once a
week for seven months over a period of twenty years. The carcinogenic
risk is 3 x 10~5, which exceeds the U.S. EPA point of departure of 1 x
10""6. However, this risk is likely to be overestimated based on
bioconcentraticn factors used in estimating concentrations in fish,
assumptions made regarding the persistence of measured concentrations
year round and into the future, and the assumption that predicted
concentrations in fish are present at the time of ingest ion.
EFM North Central, Inc. has expressed a concern that the Remedial
Investigation/Feasibility Study is lacking in information and more
study it needed. They believe that the assumptions led to erroneous
conclusions and predictions.
U.S. g*'S MSH1BE;
U.S. EPA believes that the Remedial Investigation/Feasibility Study
contains sufficient information for the agency to make a decision with
regard to selecting a remedy for the Hedblum Industries site. The
information gathered is for this decision-making purpose and is not
necessarily sufficiently detailed enough to base the actual design
upon. U.S. EPA agrees that more data needs to be gathered to support
the no action soils ranedy and to design the groundwater remedy.
-------
7.
EEVf North Central, Inc. has expressed a concern that the soil borings
analysis was not available before the monitoring wells were installed
and could have provided valuable insight to the installation. They
believe that some wells nay have been aciumod below the depth of
maximm contamination and nay not accurately reflect the existing
contaminant concentrations.
U.S. ETA'S
During monitoring well installation, split-spoon samples were
collected at the deep wells in each well nest and at the background
well. These samples were collected for lithologic description and
analytical purposes. Borehole gamma logging was originally proposed
for all wells to assist in screen placement. However, due to the
homogeneous nature of the site soils, gamma logging was not necessary.
The deeper wells were screened in the lowest 10 feet of the aquifer
and the shallower wells were screened based on organic vapor analyzer
results but generally were in the upper 10 feet of the aquifer.
8.
EW! North Central, Inc. expressed a concern about whether the contours
of the water table have substantiating data which results in a
northeasterly groundwater flow direction rather than a more easterly
or east-northeasterly direction. If the flow is more easterly, the
placement of the monitoring. wells could potentially have only
delineated half of the contaminant plume.
U.S. EPfr'S RESPCKSE;
Water table contours for the Hedblum Industries site were constructed
from July 1987 water level data for the twenty three groundwater
monitoring points listed in Table 4-2 of the Remedial Investigation
Report. This data indicates that groundwater flows in a northeasterly
direction toward the bayou. Other studies have also indicated that
the groundwater flow is to the northeast. A groundwater contamination
studWMpared by Soils and Materials Engineers, Inc. in 1976 took
grm •ail i i' elevation measurements in November 1975 and January 1976
which resulted in an indicated groundwater gradient of 73.8 x 10~4
ft/rt sloping downward at north, 57 degrees east. In a 1982 MCKR
hydrogeological study/ water levels were taken in January 1982 and in
May 1982 which showed groundwater moving northeast towards the AuSable
Heights residences. Thus, it is likely that the contaminant plume has
been characterized with the placement of the monitoring wells based
upon this information.
-------
-6-
9. oamrr:
ERf North Central, Inc. believes that the cleanup time is
D.S. Bft'S MffiiKJHSgr
The estimated implementation. time of four to five years for the
selected remedy/ Pump and Treat, includes an estimated pumping time of
approximately two and a half years. It is recognized that the
estimated calculations made are preliminary in nature and have been
based upon a limited data set and a number of simplifying assumptions.
As additional data hnmnps available, the calculations may prove to be
inaccurate. The more detailed data that needs to be gathered for the
design of the remedy may allow for a more accurate calculation of the
cleanup time than the present estimate. U.S. EPA believes that the
time estimates were adequate for glaring the remedial alternatives
and for selecting a remedy.
10. OJHEtir:
The Michigan Department of Natural Resources (MCKR) submitted a letter
dated September 27, 1989, which stated that MCNR concurs with the
remedial technology selected for the Hedblum Industries site, but does
not concur with the target cleanup level for Trichlorcethene (TCE) .
U.S.
The U.S. EPA welcomes the State's concurrence on the remedial
technology proposed for the site. However, the MCKR raises
significant issues regarding compliance with State laws. MCKR
specifically cites Act 245, and its rules. These rules restrict
degradation of waters of the State, and apply to indirect or direct
"addition of materials to groundwater from any facility or operation
which acts as a discrete or diffuse source...11 R323.2202(j) . The MCKR
further asserts that, "...to reflect Act 245 and Part 22, the target
groundwater cleanup level for TCE should be set at 1 ppb rather than 5
ppb..."
Section 121 (d) (2) (A) of the amended CERCLA states that remedies must
comply with "any promulgated standard, requirement, criteria, or
limitation under a State environmental or facility siting law that is
more stringent than any Federal standard, requirement, or limitation"
if applicable or relevant and appropriate to the hazardous substance
or release in question. General State goals that are contained in a
promulgated statute and implemented via specific requirements found in
-------
-7-
the statute or in other promulgated regulations are potential ARARs.
Vtoare such promulgated goals are general in scope, e.g. a general
prohibition against discharges to the waters of the State, compliance
oust be interpreted within the context of implementing regulations,
the specific circumstances at the site, and the remedial alternatives
being considered.
The U.S. EPA accepts that a nondegradaticn lav can be an ARAR.
However, the specific regulations which implement a general goal are
key in identifying what compliance with the goal means. If a state
has not promulgated implementing regulations, then the U.S. EPA would
have considerable latitude in determining how to comply with the goal.
The U.S. EPA may consider guidelines the state has developed related
to the provision, as well as state practices in applying the goal, but
such guidance would not be ARAR.
The State of Michigan contends that Act 245 is an ARAR for this site.
The State cites that "these rules restrict degradation of waters of
the State of Michigan, are more stringent than MCXfi, and apply to
indirect or direct 'addition of materials to groundwater fron any
facility or operation which acts as a discrete or diffuse source...'"
A literal reading of the Act and its rules indicates that the law is
prospective and is intended to prevent degradation of groundwater
quality. The remedy at the Hedblum Industries site consists of
extracting contaminated groundwater, treating (removing) the
contaminants, and discharging the treated water into a surface water
body. Therefore, the U.S. EPA does not find Act 245 and its Part 22
Rules to be ARAR. However, U.S. EPA fully supports the State's goal
to ensure that the waters of the State are protective of the public
health and welfare.
The State asserts that its 1 ppb cleanup goal for TCE is based on Act
245, and Part 22. Unfortunately, neither Act 245, nor the Part 22
Rules, provide specific remediation goals for the contaminants of
concern. We note that the only discussion regarding specific
concentration levels found in Part 22 Rules appears in 323.2205(3)
which states: "Materials at concentrations that exceed the maximum
contaminant levels for inorganic and organic chemicals.. .which are
promulgated pursuant to the safe drinking water act 42 U.S.C. 300f,
shall not be discharged into ground waters in usable aquifers..."
Therefore, even if Act 245 and Part 22 Rules were considered to be
ARAR, the rules do not provide specific criteria or numerical
standards which could be applied in establishing remedial cleanup
goals. Consequently, U.S. EPA established the cleanup goals for the
Hedblum Industries site.
-------
-8-
The U.S. EPA has developed a consistent policy regarding remediation
goals for ojroundwater. This policy nay be found in the rvnpmhpr 21,
1988 proposed revisions to the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). The U.S. EPA has stated its policy
that for surface or grounduater that is or nay be used for drinking,
MCLs are generally relevant and appropriate as cleanup standards. The
basis for this policy was that MCLs are protective of human health and
represent the level of water quality that U.S. EPA believes is
acceptable for over 200 million Americans to consume every day from
public drinking water supplies. As the enforceable standard for
public water supplies, MCLs are fully protective of human health and,
for carcinogens, fall within an acceptable lifetime risk range of 1 x
1CT4 to 1 x 10~7. When MCLs do not exist for contaminants identified
in the groundwater at a site, the Superfund program will use other
standards, advisories or criteria to determine if the response action
will achieve a level of protection within a range of 1 x 10~4 to 1 x
10~7 individual lifetime excess cancer risk.
The remedy proposed for the Hedblum Industries site establishes
cleanup goals for several contaminants. For example, U.S. EPA
proposes to use MCLs as the target cleanup levels for Trichloroethene
(5ppb), Benzene (5 ppb), Carbon Tetrachloride (Sppb), and Vinyl
Chloride (2 ppb). If one were to express the risks posed by these
contaminants, at these concentration levels, one would find that 5 ppb
of TCE represents a lifetime risk of 1.5 x 10"*, Benzene represents a
4.1 x 10"* risk, Carbon Tetrachloride represents a 1.8 x 10~5 risk,
and Vinyl Chloride represents a 1.3 x 10"4 risk. Although the MCNR
letter states: "MCNR does not support the use of MCL's as target
cleanup levels..," there is no discussion regarding the cleanup
levels for contaminants other than TCE. The State simply argues that
the MCL for TCE is unacceptable, without providing any supporting
documentation, or evidence of an overarching rationale for selecting
more stringent cleanup goals for particular contaminants. A 1 ppb
concentration level for TCE represents a 3.14 x 10~7 lifetime risk.
This risk, rVrmrrl acceptable by the MCNR for TCE, is an order of
magnitude less than the risks iVnmod acceptable for the other
contaminants. The U.S. EPA recognizes that there may be circumstances
when individual cleanup goals may be adjusted to ensure that a remedy
provides a level of protectiveness within the U.S. EPA's accepted risk
range. The remedy selected for the Hedblum Industries site does not
exceed the risk range, so adjustments to the cleanup goals are not
required. Given the inherent inconsistencies presented by the State's
insistence on a 1 ppb cleanup level for TCE at this site, the U.S. EPA
maintains that MCLs are protective, and declines to adopt a 1 ppb
cleanup goal for TCE.
------- |